diff options
Diffstat (limited to 'Documentation')
62 files changed, 4679 insertions, 2356 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX index 2a39aeba146..d05737aaa84 100644 --- a/Documentation/00-INDEX +++ b/Documentation/00-INDEX @@ -86,6 +86,8 @@ cachetlb.txt - describes the cache/TLB flushing interfaces Linux uses. cdrom/ - directory with information on the CD-ROM drivers that Linux has. +cgroups/ + - cgroups features, including cpusets and memory controller. connector/ - docs on the netlink based userspace<->kernel space communication mod. console/ @@ -98,8 +100,6 @@ cpu-load.txt - document describing how CPU load statistics are collected. cpuidle/ - info on CPU_IDLE, CPU idle state management subsystem. -cpusets.txt - - documents the cpusets feature; assign CPUs and Mem to a set of tasks. cputopology.txt - documentation on how CPU topology info is exported via sysfs. cris/ diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index e638e15a889..97ad190e13a 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -41,6 +41,49 @@ Description: for the device and attempt to bind to it. For example: # echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id +What: /sys/bus/pci/drivers/.../remove_id +Date: February 2009 +Contact: Chris Wright <chrisw@sous-sol.org> +Description: + Writing a device ID to this file will remove an ID + that was dynamically added via the new_id sysfs entry. + The format for the device ID is: + VVVV DDDD SVVV SDDD CCCC MMMM. That is Vendor ID, Device + ID, Subsystem Vendor ID, Subsystem Device ID, Class, + and Class Mask. The Vendor ID and Device ID fields are + required, the rest are optional. After successfully + removing an ID, the driver will no longer support the + device. This is useful to ensure auto probing won't + match the driver to the device. For example: + # echo "8086 10f5" > /sys/bus/pci/drivers/foo/remove_id + +What: /sys/bus/pci/rescan +Date: January 2009 +Contact: Linux PCI developers <linux-pci@vger.kernel.org> +Description: + Writing a non-zero value to this attribute will + force a rescan of all PCI buses in the system, and + re-discover previously removed devices. + Depends on CONFIG_HOTPLUG. + +What: /sys/bus/pci/devices/.../remove +Date: January 2009 +Contact: Linux PCI developers <linux-pci@vger.kernel.org> +Description: + Writing a non-zero value to this attribute will + hot-remove the PCI device and any of its children. + Depends on CONFIG_HOTPLUG. + +What: /sys/bus/pci/devices/.../rescan +Date: January 2009 +Contact: Linux PCI developers <linux-pci@vger.kernel.org> +Description: + Writing a non-zero value to this attribute will + force a rescan of the device's parent bus and all + child buses, and re-discover devices removed earlier + from this part of the device tree. + Depends on CONFIG_HOTPLUG. + What: /sys/bus/pci/devices/.../vpd Date: February 2008 Contact: Ben Hutchings <bhutchings@solarflare.com> @@ -52,3 +95,30 @@ Description: that some devices may have malformatted data. If the underlying VPD has a writable section then the corresponding section of this file will be writable. + +What: /sys/bus/pci/devices/.../virtfnN +Date: March 2009 +Contact: Yu Zhao <yu.zhao@intel.com> +Description: + This symbolic link appears when hardware supports the SR-IOV + capability and the Physical Function driver has enabled it. + The symbolic link points to the PCI device sysfs entry of the + Virtual Function whose index is N (0...MaxVFs-1). + +What: /sys/bus/pci/devices/.../dep_link +Date: March 2009 +Contact: Yu Zhao <yu.zhao@intel.com> +Description: + This symbolic link appears when hardware supports the SR-IOV + capability and the Physical Function driver has enabled it, + and this device has vendor specific dependencies with others. + The symbolic link points to the PCI device sysfs entry of + Physical Function this device depends on. + +What: /sys/bus/pci/devices/.../physfn +Date: March 2009 +Contact: Yu Zhao <yu.zhao@intel.com> +Description: + This symbolic link appears when a device is a Virtual Function. + The symbolic link points to the PCI device sysfs entry of the + Physical Function this device associates with. diff --git a/Documentation/ABI/testing/sysfs-class-regulator b/Documentation/ABI/testing/sysfs-class-regulator index 873ef1fc156..e091fa87379 100644 --- a/Documentation/ABI/testing/sysfs-class-regulator +++ b/Documentation/ABI/testing/sysfs-class-regulator @@ -4,8 +4,8 @@ KernelVersion: 2.6.26 Contact: Liam Girdwood <lrg@slimlogic.co.uk> Description: Some regulator directories will contain a field called - state. This reports the regulator enable status, for - regulators which can report that value. + state. This reports the regulator enable control, for + regulators which can report that input value. This will be one of the following strings: @@ -14,16 +14,54 @@ Description: 'unknown' 'enabled' means the regulator output is ON and is supplying - power to the system. + power to the system (assuming no error prevents it). 'disabled' means the regulator output is OFF and is not - supplying power to the system.. + supplying power to the system (unless some non-Linux + control has enabled it). 'unknown' means software cannot determine the state, or the reported state is invalid. NOTE: this field can be used in conjunction with microvolts - and microamps to determine regulator output levels. + or microamps to determine configured regulator output levels. + + +What: /sys/class/regulator/.../status +Description: + Some regulator directories will contain a field called + "status". This reports the current regulator status, for + regulators which can report that output value. + + This will be one of the following strings: + + off + on + error + fast + normal + idle + standby + + "off" means the regulator is not supplying power to the + system. + + "on" means the regulator is supplying power to the system, + and the regulator can't report a detailed operation mode. + + "error" indicates an out-of-regulation status such as being + disabled due to thermal shutdown, or voltage being unstable + because of problems with the input power supply. + + "fast", "normal", "idle", and "standby" are all detailed + regulator operation modes (described elsewhere). They + imply "on", but provide more detail. + + Note that regulator status is a function of many inputs, + not limited to control inputs from Linux. For example, + the actual load presented may trigger "error" status; or + a regulator may be enabled by another user, even though + Linux did not enable it. What: /sys/class/regulator/.../type @@ -58,7 +96,7 @@ Description: Some regulator directories will contain a field called microvolts. This holds the regulator output voltage setting measured in microvolts (i.e. E-6 Volts), for regulators - which can report that voltage. + which can report the control input for voltage. NOTE: This value should not be used to determine the regulator output voltage level as this value is the same regardless of @@ -73,7 +111,7 @@ Description: Some regulator directories will contain a field called microamps. This holds the regulator output current limit setting measured in microamps (i.e. E-6 Amps), for regulators - which can report that current. + which can report the control input for a current limit. NOTE: This value should not be used to determine the regulator output current level as this value is the same regardless of @@ -87,7 +125,7 @@ Contact: Liam Girdwood <lrg@slimlogic.co.uk> Description: Some regulator directories will contain a field called opmode. This holds the current regulator operating mode, - for regulators which can report it. + for regulators which can report that control input value. The opmode value can be one of the following strings: @@ -101,7 +139,8 @@ Description: NOTE: This value should not be used to determine the regulator output operating mode as this value is the same regardless of - whether the regulator is enabled or disabled. + whether the regulator is enabled or disabled. A "status" + attribute may be available to determine the actual mode. What: /sys/class/regulator/.../min_microvolts diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4 new file mode 100644 index 00000000000..4e79074de28 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-fs-ext4 @@ -0,0 +1,81 @@ +What: /sys/fs/ext4/<disk>/mb_stats +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + Controls whether the multiblock allocator should + collect statistics, which are shown during the unmount. + 1 means to collect statistics, 0 means not to collect + statistics + +What: /sys/fs/ext4/<disk>/mb_group_prealloc +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + The multiblock allocator will round up allocation + requests to a multiple of this tuning parameter if the + stripe size is not set in the ext4 superblock + +What: /sys/fs/ext4/<disk>/mb_max_to_scan +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + The maximum number of extents the multiblock allocator + will search to find the best extent + +What: /sys/fs/ext4/<disk>/mb_min_to_scan +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + The minimum number of extents the multiblock allocator + will search to find the best extent + +What: /sys/fs/ext4/<disk>/mb_order2_req +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + Tuning parameter which controls the minimum size for + requests (as a power of 2) where the buddy cache is + used + +What: /sys/fs/ext4/<disk>/mb_stream_req +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + Files which have fewer blocks than this tunable + parameter will have their blocks allocated out of a + block group specific preallocation pool, so that small + files are packed closely together. Each large file + will have its blocks allocated out of its own unique + preallocation pool. + +What: /sys/fs/ext4/<disk>/inode_readahead +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + Tuning parameter which controls the maximum number of + inode table blocks that ext4's inode table readahead + algorithm will pre-read into the buffer cache + +What: /sys/fs/ext4/<disk>/delayed_allocation_blocks +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + This file is read-only and shows the number of blocks + that are dirty in the page cache, but which do not + have their location in the filesystem allocated yet. + +What: /sys/fs/ext4/<disk>/lifetime_write_kbytes +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + This file is read-only and shows the number of kilobytes + of data that have been written to this filesystem since it was + created. + +What: /sys/fs/ext4/<disk>/session_write_kbytes +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + This file is read-only and shows the number of + kilobytes of data that have been written to this + filesystem since it was mounted. diff --git a/Documentation/DocBook/.gitignore b/Documentation/DocBook/.gitignore index c102c02ecf8..c6def352fe3 100644 --- a/Documentation/DocBook/.gitignore +++ b/Documentation/DocBook/.gitignore @@ -4,3 +4,7 @@ *.html *.9.gz *.9 +*.aux +*.dvi +*.log +*.out diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index bc962cda650..58c194572c7 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl @@ -199,6 +199,7 @@ X!Edrivers/pci/hotplug.c --> !Edrivers/pci/probe.c !Edrivers/pci/rom.c +!Edrivers/pci/iov.c </sect1> <sect1><title>PCI Hotplug Support Library</title> !Edrivers/pci/hotplug/pci_hotplug_core.c diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index 256defd7e17..dcf7acc720e 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt @@ -4,506 +4,356 @@ Revised Feb 12, 2004 by Martine Silbermann email: Martine.Silbermann@hp.com Revised Jun 25, 2004 by Tom L Nguyen + Revised Jul 9, 2008 by Matthew Wilcox <willy@linux.intel.com> + Copyright 2003, 2008 Intel Corporation 1. About this guide -This guide describes the basics of Message Signaled Interrupts (MSI), -the advantages of using MSI over traditional interrupt mechanisms, -and how to enable your driver to use MSI or MSI-X. Also included is -a Frequently Asked Questions (FAQ) section. - -1.1 Terminology - -PCI devices can be single-function or multi-function. In either case, -when this text talks about enabling or disabling MSI on a "device -function," it is referring to one specific PCI device and function and -not to all functions on a PCI device (unless the PCI device has only -one function). - -2. Copyright 2003 Intel Corporation - -3. What is MSI/MSI-X? - -Message Signaled Interrupt (MSI), as described in the PCI Local Bus -Specification Revision 2.3 or later, is an optional feature, and a -required feature for PCI Express devices. MSI enables a device function -to request service by sending an Inbound Memory Write on its PCI bus to -the FSB as a Message Signal Interrupt transaction. Because MSI is -generated in the form of a Memory Write, all transaction conditions, -such as a Retry, Master-Abort, Target-Abort or normal completion, are -supported. - -A PCI device that supports MSI must also support pin IRQ assertion -interrupt mechanism to provide backward compatibility for systems that -do not support MSI. In systems which support MSI, the bus driver is -responsible for initializing the message address and message data of -the device function's MSI/MSI-X capability structure during device -initial configuration. - -An MSI capable device function indicates MSI support by implementing -the MSI/MSI-X capability structure in its PCI capability list. The -device function may implement both the MSI capability structure and -the MSI-X capability structure; however, the bus driver should not -enable both. - -The MSI capability structure contains Message Control register, -Message Address register and Message Data register. These registers -provide the bus driver control over MSI. The Message Control register -indicates the MSI capability supported by the device. The Message -Address register specifies the target address and the Message Data -register specifies the characteristics of the message. To request -service, the device function writes the content of the Message Data -register to the target address. The device and its software driver -are prohibited from writing to these registers. - -The MSI-X capability structure is an optional extension to MSI. It -uses an independent and separate capability structure. There are -some key advantages to implementing the MSI-X capability structure -over the MSI capability structure as described below. - - - Support a larger maximum number of vectors per function. - - - Provide the ability for system software to configure - each vector with an independent message address and message - data, specified by a table that resides in Memory Space. - - - MSI and MSI-X both support per-vector masking. Per-vector - masking is an optional extension of MSI but a required - feature for MSI-X. Per-vector masking provides the kernel the - ability to mask/unmask a single MSI while running its - interrupt service routine. If per-vector masking is - not supported, then the device driver should provide the - hardware/software synchronization to ensure that the device - generates MSI when the driver wants it to do so. - -4. Why use MSI? - -As a benefit to the simplification of board design, MSI allows board -designers to remove out-of-band interrupt routing. MSI is another -step towards a legacy-free environment. - -Due to increasing pressure on chipset and processor packages to -reduce pin count, the need for interrupt pins is expected to -diminish over time. Devices, due to pin constraints, may implement -messages to increase performance. - -PCI Express endpoints uses INTx emulation (in-band messages) instead -of IRQ pin assertion. Using INTx emulation requires interrupt -sharing among devices connected to the same node (PCI bridge) while -MSI is unique (non-shared) and does not require BIOS configuration -support. As a result, the PCI Express technology requires MSI -support for better interrupt performance. - -Using MSI enables the device functions to support two or more -vectors, which can be configured to target different CPUs to -increase scalability. - -5. Configuring a driver to use MSI/MSI-X - -By default, the kernel will not enable MSI/MSI-X on all devices that -support this capability. The CONFIG_PCI_MSI kernel option -must be selected to enable MSI/MSI-X support. - -5.1 Including MSI/MSI-X support into the kernel - -To allow MSI/MSI-X capable device drivers to selectively enable -MSI/MSI-X (using pci_enable_msi()/pci_enable_msix() as described -below), the VECTOR based scheme needs to be enabled by setting -CONFIG_PCI_MSI during kernel config. - -Since the target of the inbound message is the local APIC, providing -CONFIG_X86_LOCAL_APIC must be enabled as well as CONFIG_PCI_MSI. - -5.2 Configuring for MSI support - -Due to the non-contiguous fashion in vector assignment of the -existing Linux kernel, this version does not support multiple -messages regardless of a device function is capable of supporting -more than one vector. To enable MSI on a device function's MSI -capability structure requires a device driver to call the function -pci_enable_msi() explicitly. - -5.2.1 API pci_enable_msi +This guide describes the basics of Message Signaled Interrupts (MSIs), +the advantages of using MSI over traditional interrupt mechanisms, how +to change your driver to use MSI or MSI-X and some basic diagnostics to +try if a device doesn't support MSIs. -int pci_enable_msi(struct pci_dev *dev) -With this new API, a device driver that wants to have MSI -enabled on its device function must call this API to enable MSI. -A successful call will initialize the MSI capability structure -with ONE vector, regardless of whether a device function is -capable of supporting multiple messages. This vector replaces the -pre-assigned dev->irq with a new MSI vector. To avoid a conflict -of the new assigned vector with existing pre-assigned vector requires -a device driver to call this API before calling request_irq(). +2. What are MSIs? -5.2.2 API pci_disable_msi +A Message Signaled Interrupt is a write from the device to a special +address which causes an interrupt to be received by the CPU. -void pci_disable_msi(struct pci_dev *dev) +The MSI capability was first specified in PCI 2.2 and was later enhanced +in PCI 3.0 to allow each interrupt to be masked individually. The MSI-X +capability was also introduced with PCI 3.0. It supports more interrupts +per device than MSI and allows interrupts to be independently configured. -This API should always be used to undo the effect of pci_enable_msi() -when a device driver is unloading. This API restores dev->irq with -the pre-assigned IOAPIC vector and switches a device's interrupt -mode to PCI pin-irq assertion/INTx emulation mode. - -Note that a device driver should always call free_irq() on the MSI vector -that it has done request_irq() on before calling this API. Failure to do -so results in a BUG_ON() and a device will be left with MSI enabled and -leaks its vector. - -5.2.3 MSI mode vs. legacy mode diagram - -The below diagram shows the events which switch the interrupt -mode on the MSI-capable device function between MSI mode and -PIN-IRQ assertion mode. - - ------------ pci_enable_msi ------------------------ - | | <=============== | | - | MSI MODE | | PIN-IRQ ASSERTION MODE | - | | ===============> | | - ------------ pci_disable_msi ------------------------ - - -Figure 1. MSI Mode vs. Legacy Mode - -In Figure 1, a device operates by default in legacy mode. Legacy -in this context means PCI pin-irq assertion or PCI-Express INTx -emulation. A successful MSI request (using pci_enable_msi()) switches -a device's interrupt mode to MSI mode. A pre-assigned IOAPIC vector -stored in dev->irq will be saved by the PCI subsystem and a new -assigned MSI vector will replace dev->irq. - -To return back to its default mode, a device driver should always call -pci_disable_msi() to undo the effect of pci_enable_msi(). Note that a -device driver should always call free_irq() on the MSI vector it has -done request_irq() on before calling pci_disable_msi(). Failure to do -so results in a BUG_ON() and a device will be left with MSI enabled and -leaks its vector. Otherwise, the PCI subsystem restores a device's -dev->irq with a pre-assigned IOAPIC vector and marks the released -MSI vector as unused. - -Once being marked as unused, there is no guarantee that the PCI -subsystem will reserve this MSI vector for a device. Depending on -the availability of current PCI vector resources and the number of -MSI/MSI-X requests from other drivers, this MSI may be re-assigned. - -For the case where the PCI subsystem re-assigns this MSI vector to -another driver, a request to switch back to MSI mode may result -in being assigned a different MSI vector or a failure if no more -vectors are available. - -5.3 Configuring for MSI-X support - -Due to the ability of the system software to configure each vector of -the MSI-X capability structure with an independent message address -and message data, the non-contiguous fashion in vector assignment of -the existing Linux kernel has no impact on supporting multiple -messages on an MSI-X capable device functions. To enable MSI-X on -a device function's MSI-X capability structure requires its device -driver to call the function pci_enable_msix() explicitly. - -The function pci_enable_msix(), once invoked, enables either -all or nothing, depending on the current availability of PCI vector -resources. If the PCI vector resources are available for the number -of vectors requested by a device driver, this function will configure -the MSI-X table of the MSI-X capability structure of a device with -requested messages. To emphasize this reason, for example, a device -may be capable for supporting the maximum of 32 vectors while its -software driver usually may request 4 vectors. It is recommended -that the device driver should call this function once during the -initialization phase of the device driver. - -Unlike the function pci_enable_msi(), the function pci_enable_msix() -does not replace the pre-assigned IOAPIC dev->irq with a new MSI -vector because the PCI subsystem writes the 1:1 vector-to-entry mapping -into the field vector of each element contained in a second argument. -Note that the pre-assigned IOAPIC dev->irq is valid only if the device -operates in PIN-IRQ assertion mode. In MSI-X mode, any attempt at -using dev->irq by the device driver to request for interrupt service -may result in unpredictable behavior. - -For each MSI-X vector granted, a device driver is responsible for calling -other functions like request_irq(), enable_irq(), etc. to enable -this vector with its corresponding interrupt service handler. It is -a device driver's choice to assign all vectors with the same -interrupt service handler or each vector with a unique interrupt -service handler. - -5.3.1 Handling MMIO address space of MSI-X Table - -The PCI 3.0 specification has implementation notes that MMIO address -space for a device's MSI-X structure should be isolated so that the -software system can set different pages for controlling accesses to the -MSI-X structure. The implementation of MSI support requires the PCI -subsystem, not a device driver, to maintain full control of the MSI-X -table/MSI-X PBA (Pending Bit Array) and MMIO address space of the MSI-X -table/MSI-X PBA. A device driver should not access the MMIO address -space of the MSI-X table/MSI-X PBA. - -5.3.2 API pci_enable_msix +Devices may support both MSI and MSI-X, but only one can be enabled at +a time. -int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec) -This API enables a device driver to request the PCI subsystem -to enable MSI-X messages on its hardware device. Depending on -the availability of PCI vectors resources, the PCI subsystem enables -either all or none of the requested vectors. +3. Why use MSIs? + +There are three reasons why using MSIs can give an advantage over +traditional pin-based interrupts. + +Pin-based PCI interrupts are often shared amongst several devices. +To support this, the kernel must call each interrupt handler associated +with an interrupt, which leads to reduced performance for the system as +a whole. MSIs are never shared, so this problem cannot arise. + +When a device writes data to memory, then raises a pin-based interrupt, +it is possible that the interrupt may arrive before all the data has +arrived in memory (this becomes more likely with devices behind PCI-PCI +bridges). In order to ensure that all the data has arrived in memory, +the interrupt handler must read a register on the device which raised +the interrupt. PCI transaction ordering rules require that all the data +arrives in memory before the value can be returned from the register. +Using MSIs avoids this problem as the interrupt-generating write cannot +pass the data writes, so by the time the interrupt is raised, the driver +knows that all the data has arrived in memory. + +PCI devices can only support a single pin-based interrupt per function. +Often drivers have to query the device to find out what event has +occurred, slowing down interrupt handling for the common case. With +MSIs, a device can support more interrupts, allowing each interrupt +to be specialised to a different purpose. One possible design gives +infrequent conditions (such as errors) their own interrupt which allows +the driver to handle the normal interrupt handling path more efficiently. +Other possible designs include giving one interrupt to each packet queue +in a network card or each port in a storage controller. + + +4. How to use MSIs + +PCI devices are initialised to use pin-based interrupts. The device +driver has to set up the device to use MSI or MSI-X. Not all machines +support MSIs correctly, and for those machines, the APIs described below +will simply fail and the device will continue to use pin-based interrupts. + +4.1 Include kernel support for MSIs + +To support MSI or MSI-X, the kernel must be built with the CONFIG_PCI_MSI +option enabled. This option is only available on some architectures, +and it may depend on some other options also being set. For example, +on x86, you must also enable X86_UP_APIC or SMP in order to see the +CONFIG_PCI_MSI option. + +4.2 Using MSI + +Most of the hard work is done for the driver in the PCI layer. It simply +has to request that the PCI layer set up the MSI capability for this +device. + +4.2.1 pci_enable_msi + +int pci_enable_msi(struct pci_dev *dev) + +A successful call will allocate ONE interrupt to the device, regardless +of how many MSIs the device supports. The device will be switched from +pin-based interrupt mode to MSI mode. The dev->irq number is changed +to a new number which represents the message signaled interrupt. +This function should be called before the driver calls request_irq() +since enabling MSIs disables the pin-based IRQ and the driver will not +receive interrupts on the old interrupt. + +4.2.2 pci_enable_msi_block + +int pci_enable_msi_block(struct pci_dev *dev, int count) + +This variation on the above call allows a device driver to request multiple +MSIs. The MSI specification only allows interrupts to be allocated in +powers of two, up to a maximum of 2^5 (32). + +If this function returns 0, it has succeeded in allocating at least as many +interrupts as the driver requested (it may have allocated more in order +to satisfy the power-of-two requirement). In this case, the function +enables MSI on this device and updates dev->irq to be the lowest of +the new interrupts assigned to it. The other interrupts assigned to +the device are in the range dev->irq to dev->irq + count - 1. + +If this function returns a negative number, it indicates an error and +the driver should not attempt to request any more MSI interrupts for +this device. If this function returns a positive number, it will be +less than 'count' and indicate the number of interrupts that could have +been allocated. In neither case will the irq value have been +updated, nor will the device have been switched into MSI mode. + +The device driver must decide what action to take if +pci_enable_msi_block() returns a value less than the number asked for. +Some devices can make use of fewer interrupts than the maximum they +request; in this case the driver should call pci_enable_msi_block() +again. Note that it is not guaranteed to succeed, even when the +'count' has been reduced to the value returned from a previous call to +pci_enable_msi_block(). This is because there are multiple constraints +on the number of vectors that can be allocated; pci_enable_msi_block() +will return as soon as it finds any constraint that doesn't allow the +call to succeed. + +4.2.3 pci_disable_msi + +void pci_disable_msi(struct pci_dev *dev) -Argument 'dev' points to the device (pci_dev) structure. +This function should be used to undo the effect of pci_enable_msi() or +pci_enable_msi_block(). Calling it restores dev->irq to the pin-based +interrupt number and frees the previously allocated message signaled +interrupt(s). The interrupt may subsequently be assigned to another +device, so drivers should not cache the value of dev->irq. -Argument 'entries' is a pointer to an array of msix_entry structs. -The number of entries is indicated in argument 'nvec'. -struct msix_entry is defined in /driver/pci/msi.h: +A device driver must always call free_irq() on the interrupt(s) +for which it has called request_irq() before calling this function. +Failure to do so will result in a BUG_ON(), the device will be left with +MSI enabled and will leak its vector. + +4.3 Using MSI-X + +The MSI-X capability is much more flexible than the MSI capability. +It supports up to 2048 interrupts, each of which can be controlled +independently. To support this flexibility, drivers must use an array of +`struct msix_entry': struct msix_entry { u16 vector; /* kernel uses to write alloc vector */ u16 entry; /* driver uses to specify entry */ }; -A device driver is responsible for initializing the field 'entry' of -each element with a unique entry supported by MSI-X table. Otherwise, --EINVAL will be returned as a result. A successful return of zero -indicates the PCI subsystem completed initializing each of the requested -entries of the MSI-X table with message address and message data. -Last but not least, the PCI subsystem will write the 1:1 -vector-to-entry mapping into the field 'vector' of each element. A -device driver is responsible for keeping track of allocated MSI-X -vectors in its internal data structure. - -A return of zero indicates that the number of MSI-X vectors was -successfully allocated. A return of greater than zero indicates -MSI-X vector shortage. Or a return of less than zero indicates -a failure. This failure may be a result of duplicate entries -specified in second argument, or a result of no available vector, -or a result of failing to initialize MSI-X table entries. - -5.3.3 API pci_disable_msix +This allows for the device to use these interrupts in a sparse fashion; +for example it could use interrupts 3 and 1027 and allocate only a +two-element array. The driver is expected to fill in the 'entry' value +in each element of the array to indicate which entries it wants the kernel +to assign interrupts for. It is invalid to fill in two entries with the +same number. + +4.3.1 pci_enable_msix + +int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec) + +Calling this function asks the PCI subsystem to allocate 'nvec' MSIs. +The 'entries' argument is a pointer to an array of msix_entry structs +which should be at least 'nvec' entries in size. On success, the +function will return 0 and the device will have been switched into +MSI-X interrupt mode. The 'vector' elements in each entry will have +been filled in with the interrupt number. The driver should then call +request_irq() for each 'vector' that it decides to use. + +If this function returns a negative number, it indicates an error and +the driver should not attempt to allocate any more MSI-X interrupts for +this device. If it returns a positive number, it indicates the maximum +number of interrupt vectors that could have been allocated. See example +below. + +This function, in contrast with pci_enable_msi(), does not adjust +dev->irq. The device will not generate interrupts for this interrupt +number once MSI-X is enabled. The device driver is responsible for +keeping track of the interrupts assigned to the MSI-X vectors so it can +free them again later. + +Device drivers should normally call this function once per device +during the initialization phase. + +It is ideal if drivers can cope with a variable number of MSI-X interrupts, +there are many reasons why the platform may not be able to provide the +exact number a driver asks for. + +A request loop to achieve that might look like: + +static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec) +{ + while (nvec >= FOO_DRIVER_MINIMUM_NVEC) { + rc = pci_enable_msix(adapter->pdev, + adapter->msix_entries, nvec); + if (rc > 0) + nvec = rc; + else + return rc; + } + + return -ENOSPC; +} + +4.3.2 pci_disable_msix void pci_disable_msix(struct pci_dev *dev) -This API should always be used to undo the effect of pci_enable_msix() -when a device driver is unloading. Note that a device driver should -always call free_irq() on all MSI-X vectors it has done request_irq() -on before calling this API. Failure to do so results in a BUG_ON() and -a device will be left with MSI-X enabled and leaks its vectors. - -5.3.4 MSI-X mode vs. legacy mode diagram - -The below diagram shows the events which switch the interrupt -mode on the MSI-X capable device function between MSI-X mode and -PIN-IRQ assertion mode (legacy). - - ------------ pci_enable_msix(,,n) ------------------------ - | | <=============== | | - | MSI-X MODE | | PIN-IRQ ASSERTION MODE | - | | ===============> | | - ------------ pci_disable_msix ------------------------ - -Figure 2. MSI-X Mode vs. Legacy Mode - -In Figure 2, a device operates by default in legacy mode. A -successful MSI-X request (using pci_enable_msix()) switches a -device's interrupt mode to MSI-X mode. A pre-assigned IOAPIC vector -stored in dev->irq will be saved by the PCI subsystem; however, -unlike MSI mode, the PCI subsystem will not replace dev->irq with -assigned MSI-X vector because the PCI subsystem already writes the 1:1 -vector-to-entry mapping into the field 'vector' of each element -specified in second argument. - -To return back to its default mode, a device driver should always call -pci_disable_msix() to undo the effect of pci_enable_msix(). Note that -a device driver should always call free_irq() on all MSI-X vectors it -has done request_irq() on before calling pci_disable_msix(). Failure -to do so results in a BUG_ON() and a device will be left with MSI-X -enabled and leaks its vectors. Otherwise, the PCI subsystem switches a -device function's interrupt mode from MSI-X mode to legacy mode and -marks all allocated MSI-X vectors as unused. - -Once being marked as unused, there is no guarantee that the PCI -subsystem will reserve these MSI-X vectors for a device. Depending on -the availability of current PCI vector resources and the number of -MSI/MSI-X requests from other drivers, these MSI-X vectors may be -re-assigned. - -For the case where the PCI subsystem re-assigned these MSI-X vectors -to other drivers, a request to switch back to MSI-X mode may result -being assigned with another set of MSI-X vectors or a failure if no -more vectors are available. - -5.4 Handling function implementing both MSI and MSI-X capabilities - -For the case where a function implements both MSI and MSI-X -capabilities, the PCI subsystem enables a device to run either in MSI -mode or MSI-X mode but not both. A device driver determines whether it -wants MSI or MSI-X enabled on its hardware device. Once a device -driver requests for MSI, for example, it is prohibited from requesting -MSI-X; in other words, a device driver is not permitted to ping-pong -between MSI mod MSI-X mode during a run-time. - -5.5 Hardware requirements for MSI/MSI-X support - -MSI/MSI-X support requires support from both system hardware and -individual hardware device functions. - -5.5.1 Required x86 hardware support - -Since the target of MSI address is the local APIC CPU, enabling -MSI/MSI-X support in the Linux kernel is dependent on whether existing -system hardware supports local APIC. Users should verify that their -system supports local APIC operation by testing that it runs when -CONFIG_X86_LOCAL_APIC=y. - -In SMP environment, CONFIG_X86_LOCAL_APIC is automatically set; -however, in UP environment, users must manually set -CONFIG_X86_LOCAL_APIC. Once CONFIG_X86_LOCAL_APIC=y, setting -CONFIG_PCI_MSI enables the VECTOR based scheme and the option for -MSI-capable device drivers to selectively enable MSI/MSI-X. - -Note that CONFIG_X86_IO_APIC setting is irrelevant because MSI/MSI-X -vector is allocated new during runtime and MSI/MSI-X support does not -depend on BIOS support. This key independency enables MSI/MSI-X -support on future IOxAPIC free platforms. - -5.5.2 Device hardware support - -The hardware device function supports MSI by indicating the -MSI/MSI-X capability structure on its PCI capability list. By -default, this capability structure will not be initialized by -the kernel to enable MSI during the system boot. In other words, -the device function is running on its default pin assertion mode. -Note that in many cases the hardware supporting MSI have bugs, -which may result in system hangs. The software driver of specific -MSI-capable hardware is responsible for deciding whether to call -pci_enable_msi or not. A return of zero indicates the kernel -successfully initialized the MSI/MSI-X capability structure of the -device function. The device function is now running on MSI/MSI-X mode. - -5.6 How to tell whether MSI/MSI-X is enabled on device function - -At the driver level, a return of zero from the function call of -pci_enable_msi()/pci_enable_msix() indicates to a device driver that -its device function is initialized successfully and ready to run in -MSI/MSI-X mode. - -At the user level, users can use the command 'cat /proc/interrupts' -to display the vectors allocated for devices and their interrupt -MSI/MSI-X modes ("PCI-MSI"/"PCI-MSI-X"). Below shows MSI mode is -enabled on a SCSI Adaptec 39320D Ultra320 controller. - - CPU0 CPU1 - 0: 324639 0 IO-APIC-edge timer - 1: 1186 0 IO-APIC-edge i8042 - 2: 0 0 XT-PIC cascade - 12: 2797 0 IO-APIC-edge i8042 - 14: 6543 0 IO-APIC-edge ide0 - 15: 1 0 IO-APIC-edge ide1 -169: 0 0 IO-APIC-level uhci-hcd -185: 0 0 IO-APIC-level uhci-hcd -193: 138 10 PCI-MSI aic79xx -201: 30 0 PCI-MSI aic79xx -225: 30 0 IO-APIC-level aic7xxx -233: 30 0 IO-APIC-level aic7xxx -NMI: 0 0 -LOC: 324553 325068 -ERR: 0 -MIS: 0 - -6. MSI quirks - -Several PCI chipsets or devices are known to not support MSI. -The PCI stack provides 3 possible levels of MSI disabling: -* on a single device -* on all devices behind a specific bridge -* globally - -6.1. Disabling MSI on a single device - -Under some circumstances it might be required to disable MSI on a -single device. This may be achieved by either not calling pci_enable_msi() -or all, or setting the pci_dev->no_msi flag before (most of the time -in a quirk). - -6.2. Disabling MSI below a bridge - -The vast majority of MSI quirks are required by PCI bridges not -being able to route MSI between busses. In this case, MSI have to be -disabled on all devices behind this bridge. It is achieves by setting -the PCI_BUS_FLAGS_NO_MSI flag in the pci_bus->bus_flags of the bridge -subordinate bus. There is no need to set the same flag on bridges that -are below the broken bridge. When pci_enable_msi() is called to enable -MSI on a device, pci_msi_supported() takes care of checking the NO_MSI -flag in all parent busses of the device. - -Some bridges actually support dynamic MSI support enabling/disabling -by changing some bits in their PCI configuration space (especially -the Hypertransport chipsets such as the nVidia nForce and Serverworks -HT2000). It may then be required to update the NO_MSI flag on the -corresponding devices in the sysfs hierarchy. To enable MSI support -on device "0000:00:0e", do: - - echo 1 > /sys/bus/pci/devices/0000:00:0e/msi_bus - -To disable MSI support, echo 0 instead of 1. Note that it should be -used with caution since changing this value might break interrupts. - -6.3. Disabling MSI globally - -Some extreme cases may require to disable MSI globally on the system. -For now, the only known case is a Serverworks PCI-X chipsets (MSI are -not supported on several busses that are not all connected to the -chipset in the Linux PCI hierarchy). In the vast majority of other -cases, disabling only behind a specific bridge is enough. - -For debugging purpose, the user may also pass pci=nomsi on the kernel -command-line to explicitly disable MSI globally. But, once the appro- -priate quirks are added to the kernel, this option should not be -required anymore. - -6.4. Finding why MSI cannot be enabled on a device - -Assuming that MSI are not enabled on a device, you should look at -dmesg to find messages that quirks may output when disabling MSI -on some devices, some bridges or even globally. -Then, lspci -t gives the list of bridges above a device. Reading -/sys/bus/pci/devices/0000:00:0e/msi_bus will tell you whether MSI -are enabled (1) or disabled (0). In 0 is found in a single bridge -msi_bus file above the device, MSI cannot be enabled. - -7. FAQ - -Q1. Are there any limitations on using the MSI? - -A1. If the PCI device supports MSI and conforms to the -specification and the platform supports the APIC local bus, -then using MSI should work. - -Q2. Will it work on all the Pentium processors (P3, P4, Xeon, -AMD processors)? In P3 IPI's are transmitted on the APIC local -bus and in P4 and Xeon they are transmitted on the system -bus. Are there any implications with this? - -A2. MSI support enables a PCI device sending an inbound -memory write (0xfeexxxxx as target address) on its PCI bus -directly to the FSB. Since the message address has a -redirection hint bit cleared, it should work. - -Q3. The target address 0xfeexxxxx will be translated by the -Host Bridge into an interrupt message. Are there any -limitations on the chipsets such as Intel 8xx, Intel e7xxx, -or VIA? - -A3. If these chipsets support an inbound memory write with -target address set as 0xfeexxxxx, as conformed to PCI -specification 2.3 or latest, then it should work. - -Q4. From the driver point of view, if the MSI is lost because -of errors occurring during inbound memory write, then it may -wait forever. Is there a mechanism for it to recover? - -A4. Since the target of the transaction is an inbound memory -write, all transaction termination conditions (Retry, -Master-Abort, Target-Abort, or normal completion) are -supported. A device sending an MSI must abide by all the PCI -rules and conditions regarding that inbound memory write. So, -if a retry is signaled it must retry, etc... We believe that -the recommendation for Abort is also a retry (refer to PCI -specification 2.3 or latest). +This API should be used to undo the effect of pci_enable_msix(). It frees +the previously allocated message signaled interrupts. The interrupts may +subsequently be assigned to another device, so drivers should not cache +the value of the 'vector' elements over a call to pci_disable_msix(). + +A device driver must always call free_irq() on the interrupt(s) +for which it has called request_irq() before calling this function. +Failure to do so will result in a BUG_ON(), the device will be left with +MSI enabled and will leak its vector. + +4.3.3 The MSI-X Table + +The MSI-X capability specifies a BAR and offset within that BAR for the +MSI-X Table. This address is mapped by the PCI subsystem, and should not +be accessed directly by the device driver. If the driver wishes to +mask or unmask an interrupt, it should call disable_irq() / enable_irq(). + +4.4 Handling devices implementing both MSI and MSI-X capabilities + +If a device implements both MSI and MSI-X capabilities, it can +run in either MSI mode or MSI-X mode but not both simultaneously. +This is a requirement of the PCI spec, and it is enforced by the +PCI layer. Calling pci_enable_msi() when MSI-X is already enabled or +pci_enable_msix() when MSI is already enabled will result in an error. +If a device driver wishes to switch between MSI and MSI-X at runtime, +it must first quiesce the device, then switch it back to pin-interrupt +mode, before calling pci_enable_msi() or pci_enable_msix() and resuming +operation. This is not expected to be a common operation but may be +useful for debugging or testing during development. + +4.5 Considerations when using MSIs + +4.5.1 Choosing between MSI-X and MSI + +If your device supports both MSI-X and MSI capabilities, you should use +the MSI-X facilities in preference to the MSI facilities. As mentioned +above, MSI-X supports any number of interrupts between 1 and 2048. +In constrast, MSI is restricted to a maximum of 32 interrupts (and +must be a power of two). In addition, the MSI interrupt vectors must +be allocated consecutively, so the system may not be able to allocate +as many vectors for MSI as it could for MSI-X. On some platforms, MSI +interrupts must all be targetted at the same set of CPUs whereas MSI-X +interrupts can all be targetted at different CPUs. + +4.5.2 Spinlocks + +Most device drivers have a per-device spinlock which is taken in the +interrupt handler. With pin-based interrupts or a single MSI, it is not +necessary to disable interrupts (Linux guarantees the same interrupt will +not be re-entered). If a device uses multiple interrupts, the driver +must disable interrupts while the lock is held. If the device sends +a different interrupt, the driver will deadlock trying to recursively +acquire the spinlock. + +There are two solutions. The first is to take the lock with +spin_lock_irqsave() or spin_lock_irq() (see +Documentation/DocBook/kernel-locking). The second is to specify +IRQF_DISABLED to request_irq() so that the kernel runs the entire +interrupt routine with interrupts disabled. + +If your MSI interrupt routine does not hold the lock for the whole time +it is running, the first solution may be best. The second solution is +normally preferred as it avoids making two transitions from interrupt +disabled to enabled and back again. + +4.6 How to tell whether MSI/MSI-X is enabled on a device + +Using 'lspci -v' (as root) may show some devices with "MSI", "Message +Signalled Interrupts" or "MSI-X" capabilities. Each of these capabilities +has an 'Enable' flag which will be followed with either "+" (enabled) +or "-" (disabled). + + +5. MSI quirks + +Several PCI chipsets or devices are known not to support MSIs. +The PCI stack provides three ways to disable MSIs: + +1. globally +2. on all devices behind a specific bridge +3. on a single device + +5.1. Disabling MSIs globally + +Some host chipsets simply don't support MSIs properly. If we're +lucky, the manufacturer knows this and has indicated it in the ACPI +FADT table. In this case, Linux will automatically disable MSIs. +Some boards don't include this information in the table and so we have +to detect them ourselves. The complete list of these is found near the +quirk_disable_all_msi() function in drivers/pci/quirks.c. + +If you have a board which has problems with MSIs, you can pass pci=nomsi +on the kernel command line to disable MSIs on all devices. It would be +in your best interests to report the problem to linux-pci@vger.kernel.org +including a full 'lspci -v' so we can add the quirks to the kernel. + +5.2. Disabling MSIs below a bridge + +Some PCI bridges are not able to route MSIs between busses properly. +In this case, MSIs must be disabled on all devices behind the bridge. + +Some bridges allow you to enable MSIs by changing some bits in their +PCI configuration space (especially the Hypertransport chipsets such +as the nVidia nForce and Serverworks HT2000). As with host chipsets, +Linux mostly knows about them and automatically enables MSIs if it can. +If you have a bridge which Linux doesn't yet know about, you can enable +MSIs in configuration space using whatever method you know works, then +enable MSIs on that bridge by doing: + + echo 1 > /sys/bus/pci/devices/$bridge/msi_bus + +where $bridge is the PCI address of the bridge you've enabled (eg +0000:00:0e.0). + +To disable MSIs, echo 0 instead of 1. Changing this value should be +done with caution as it can break interrupt handling for all devices +below this bridge. + +Again, please notify linux-pci@vger.kernel.org of any bridges that need +special handling. + +5.3. Disabling MSIs on a single device + +Some devices are known to have faulty MSI implementations. Usually this +is handled in the individual device driver but occasionally it's necessary +to handle this with a quirk. Some drivers have an option to disable use +of MSI. While this is a convenient workaround for the driver author, +it is not good practise, and should not be emulated. + +5.4. Finding why MSIs are disabled on a device + +From the above three sections, you can see that there are many reasons +why MSIs may not be enabled for a given device. Your first step should +be to examine your dmesg carefully to determine whether MSIs are enabled +for your machine. You should also check your .config to be sure you +have enabled CONFIG_PCI_MSI. + +Then, 'lspci -t' gives the list of bridges above a device. Reading +/sys/bus/pci/devices/*/msi_bus will tell you whether MSI are enabled (1) +or disabled (0). If 0 is found in any of the msi_bus files belonging +to bridges between the PCI root and the device, MSIs are disabled. + +It is also worth checking the device driver to see whether it supports MSIs. +For example, it may contain calls to pci_enable_msi(), pci_enable_msix() or +pci_enable_msi_block(). diff --git a/Documentation/PCI/pci-iov-howto.txt b/Documentation/PCI/pci-iov-howto.txt new file mode 100644 index 00000000000..fc73ef5d65b --- /dev/null +++ b/Documentation/PCI/pci-iov-howto.txt @@ -0,0 +1,99 @@ + PCI Express I/O Virtualization Howto + Copyright (C) 2009 Intel Corporation + Yu Zhao <yu.zhao@intel.com> + + +1. Overview + +1.1 What is SR-IOV + +Single Root I/O Virtualization (SR-IOV) is a PCI Express Extended +capability which makes one physical device appear as multiple virtual +devices. The physical device is referred to as Physical Function (PF) +while the virtual devices are referred to as Virtual Functions (VF). +Allocation of the VF can be dynamically controlled by the PF via +registers encapsulated in the capability. By default, this feature is +not enabled and the PF behaves as traditional PCIe device. Once it's +turned on, each VF's PCI configuration space can be accessed by its own +Bus, Device and Function Number (Routing ID). And each VF also has PCI +Memory Space, which is used to map its register set. VF device driver +operates on the register set so it can be functional and appear as a +real existing PCI device. + +2. User Guide + +2.1 How can I enable SR-IOV capability + +The device driver (PF driver) will control the enabling and disabling +of the capability via API provided by SR-IOV core. If the hardware +has SR-IOV capability, loading its PF driver would enable it and all +VFs associated with the PF. + +2.2 How can I use the Virtual Functions + +The VF is treated as hot-plugged PCI devices in the kernel, so they +should be able to work in the same way as real PCI devices. The VF +requires device driver that is same as a normal PCI device's. + +3. Developer Guide + +3.1 SR-IOV API + +To enable SR-IOV capability: + int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn); + 'nr_virtfn' is number of VFs to be enabled. + +To disable SR-IOV capability: + void pci_disable_sriov(struct pci_dev *dev); + +To notify SR-IOV core of Virtual Function Migration: + irqreturn_t pci_sriov_migration(struct pci_dev *dev); + +3.2 Usage example + +Following piece of code illustrates the usage of the SR-IOV API. + +static int __devinit dev_probe(struct pci_dev *dev, const struct pci_device_id *id) +{ + pci_enable_sriov(dev, NR_VIRTFN); + + ... + + return 0; +} + +static void __devexit dev_remove(struct pci_dev *dev) +{ + pci_disable_sriov(dev); + + ... +} + +static int dev_suspend(struct pci_dev *dev, pm_message_t state) +{ + ... + + return 0; +} + +static int dev_resume(struct pci_dev *dev) +{ + ... + + return 0; +} + +static void dev_shutdown(struct pci_dev *dev) +{ + ... +} + +static struct pci_driver dev_driver = { + .name = "SR-IOV Physical Function driver", + .id_table = dev_id_table, + .probe = dev_probe, + .remove = __devexit_p(dev_remove), + .suspend = dev_suspend, + .resume = dev_resume, + .shutdown = dev_shutdown, +}; diff --git a/Documentation/RCU/listRCU.txt b/Documentation/RCU/listRCU.txt index 1fd175368a8..4349c1487e9 100644 --- a/Documentation/RCU/listRCU.txt +++ b/Documentation/RCU/listRCU.txt @@ -118,7 +118,7 @@ Following are the RCU equivalents for these two functions: list_for_each_entry(e, list, list) { if (!audit_compare_rule(rule, &e->rule)) { list_del_rcu(&e->list); - call_rcu(&e->rcu, audit_free_rule, e); + call_rcu(&e->rcu, audit_free_rule); return 0; } } @@ -206,7 +206,7 @@ RCU ("read-copy update") its name. The RCU code is as follows: ne->rule.action = newaction; ne->rule.file_count = newfield_count; list_replace_rcu(e, ne); - call_rcu(&e->rcu, audit_free_rule, e); + call_rcu(&e->rcu, audit_free_rule); return 0; } } @@ -283,7 +283,7 @@ flag under the spinlock as follows: list_del_rcu(&e->list); e->deleted = 1; spin_unlock(&e->lock); - call_rcu(&e->rcu, audit_free_rule, e); + call_rcu(&e->rcu, audit_free_rule); return 0; } } diff --git a/Documentation/RCU/rcu.txt b/Documentation/RCU/rcu.txt index 95821a29ae4..7aa2002ade7 100644 --- a/Documentation/RCU/rcu.txt +++ b/Documentation/RCU/rcu.txt @@ -81,7 +81,7 @@ o I hear that RCU needs work in order to support realtime kernels? This work is largely completed. Realtime-friendly RCU can be enabled via the CONFIG_PREEMPT_RCU kernel configuration parameter. However, work is in progress for enabling priority boosting of - preempted RCU read-side critical sections.This is needed if you + preempted RCU read-side critical sections. This is needed if you have CPU-bound realtime threads. o Where can I find more information on RCU? diff --git a/Documentation/RCU/rculist_nulls.txt b/Documentation/RCU/rculist_nulls.txt index 239f542d48b..6389dec3345 100644 --- a/Documentation/RCU/rculist_nulls.txt +++ b/Documentation/RCU/rculist_nulls.txt @@ -21,7 +21,7 @@ if (obj) { /* * Because a writer could delete object, and a writer could * reuse these object before the RCU grace period, we - * must check key after geting the reference on object + * must check key after getting the reference on object */ if (obj->key != key) { // not the object we expected put_ref(obj); @@ -117,7 +117,7 @@ a race (some writer did a delete and/or a move of an object to another chain) checking the final 'nulls' value if the lookup met the end of chain. If final 'nulls' value is not the slot number, then we must restart the lookup at -the begining. If the object was moved to same chain, +the beginning. If the object was moved to the same chain, then the reader doesnt care : It might eventually scan the list again without harm. diff --git a/Documentation/cgroups/00-INDEX b/Documentation/cgroups/00-INDEX new file mode 100644 index 00000000000..3f58fa3d6d0 --- /dev/null +++ b/Documentation/cgroups/00-INDEX @@ -0,0 +1,18 @@ +00-INDEX + - this file +cgroups.txt + - Control Groups definition, implementation details, examples and API. +cpuacct.txt + - CPU Accounting Controller; account CPU usage for groups of tasks. +cpusets.txt + - documents the cpusets feature; assign CPUs and Mem to a set of tasks. +devices.txt + - Device Whitelist Controller; description, interface and security. +freezer-subsystem.txt + - checkpointing; rationale to not use signals, interface. +memcg_test.txt + - Memory Resource Controller; implementation details. +memory.txt + - Memory Resource Controller; design, accounting, interface, testing. +resource_counter.txt + - Resource Counter API. diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index 93feb844448..6eb1a97e88c 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -56,7 +56,7 @@ hierarchy, and a set of subsystems; each subsystem has system-specific state attached to each cgroup in the hierarchy. Each hierarchy has an instance of the cgroup virtual filesystem associated with it. -At any one time there may be multiple active hierachies of task +At any one time there may be multiple active hierarchies of task cgroups. Each hierarchy is a partition of all tasks in the system. User level code may create and destroy cgroups by name in an @@ -124,10 +124,10 @@ following lines: / \ Prof (15%) students (5%) -Browsers like firefox/lynx go into the WWW network class, while (k)nfsd go +Browsers like Firefox/Lynx go into the WWW network class, while (k)nfsd go into NFS network class. -At the same time firefox/lynx will share an appropriate CPU/Memory class +At the same time Firefox/Lynx will share an appropriate CPU/Memory class depending on who launched it (prof/student). With the ability to classify tasks differently for different resources @@ -325,7 +325,7 @@ and then start a subshell 'sh' in that cgroup: Creating, modifying, using the cgroups can be done through the cgroup virtual filesystem. -To mount a cgroup hierarchy will all available subsystems, type: +To mount a cgroup hierarchy with all available subsystems, type: # mount -t cgroup xxx /dev/cgroup The "xxx" is not interpreted by the cgroup code, but will appear in @@ -333,12 +333,23 @@ The "xxx" is not interpreted by the cgroup code, but will appear in To mount a cgroup hierarchy with just the cpuset and numtasks subsystems, type: -# mount -t cgroup -o cpuset,numtasks hier1 /dev/cgroup +# mount -t cgroup -o cpuset,memory hier1 /dev/cgroup To change the set of subsystems bound to a mounted hierarchy, just remount with different options: +# mount -o remount,cpuset,ns hier1 /dev/cgroup -# mount -o remount,cpuset,ns /dev/cgroup +Now memory is removed from the hierarchy and ns is added. + +Note this will add ns to the hierarchy but won't remove memory or +cpuset, because the new options are appended to the old ones: +# mount -o remount,ns /dev/cgroup + +To Specify a hierarchy's release_agent: +# mount -t cgroup -o cpuset,release_agent="/sbin/cpuset_release_agent" \ + xxx /dev/cgroup + +Note that specifying 'release_agent' more than once will return failure. Note that changing the set of subsystems is currently only supported when the hierarchy consists of a single (root) cgroup. Supporting @@ -349,6 +360,11 @@ Then under /dev/cgroup you can find a tree that corresponds to the tree of the cgroups in the system. For instance, /dev/cgroup is the cgroup that holds the whole system. +If you want to change the value of release_agent: +# echo "/sbin/new_release_agent" > /dev/cgroup/release_agent + +It can also be changed via remount. + If you want to create a new cgroup under /dev/cgroup: # cd /dev/cgroup # mkdir my_cgroup @@ -476,11 +492,13 @@ cgroup->parent is still valid. (Note - can also be called for a newly-created cgroup if an error occurs after this subsystem's create() method has been called for the new cgroup). -void pre_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp); +int pre_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp); Called before checking the reference count on each subsystem. This may be useful for subsystems which have some extra references even if -there are not tasks in the cgroup. +there are not tasks in the cgroup. If pre_destroy() returns error code, +rmdir() will fail with it. From this behavior, pre_destroy() can be +called multiple times against a cgroup. int can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, struct task_struct *task) @@ -521,7 +539,7 @@ always handled well. void post_clone(struct cgroup_subsys *ss, struct cgroup *cgrp) (cgroup_mutex held by caller) -Called at the end of cgroup_clone() to do any paramater +Called at the end of cgroup_clone() to do any parameter initialization which might be required before a task could attach. For example in cpusets, no task may attach before 'cpus' and 'mems' are set up. diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt index 0611e9528c7..f9ca389dddf 100644 --- a/Documentation/cgroups/cpusets.txt +++ b/Documentation/cgroups/cpusets.txt @@ -131,7 +131,7 @@ Cpusets extends these two mechanisms as follows: - The hierarchy of cpusets can be mounted at /dev/cpuset, for browsing and manipulation from user space. - A cpuset may be marked exclusive, which ensures that no other - cpuset (except direct ancestors and descendents) may contain + cpuset (except direct ancestors and descendants) may contain any overlapping CPUs or Memory Nodes. - You can list all the tasks (by pid) attached to any cpuset. @@ -226,7 +226,7 @@ nodes with memory--using the cpuset_track_online_nodes() hook. -------------------------------- If a cpuset is cpu or mem exclusive, no other cpuset, other than -a direct ancestor or descendent, may share any of the same CPUs or +a direct ancestor or descendant, may share any of the same CPUs or Memory Nodes. A cpuset that is mem_exclusive *or* mem_hardwall is "hardwalled", @@ -427,7 +427,7 @@ child cpusets have this flag enabled. When doing this, you don't usually want to leave any unpinned tasks in the top cpuset that might use non-trivial amounts of CPU, as such tasks may be artificially constrained to some subset of CPUs, depending on -the particulars of this flag setting in descendent cpusets. Even if +the particulars of this flag setting in descendant cpusets. Even if such a task could use spare CPU cycles in some other CPUs, the kernel scheduler might not consider the possibility of load balancing that task to that underused CPU. @@ -531,9 +531,9 @@ be idle. Of course it takes some searching cost to find movable tasks and/or idle CPUs, the scheduler might not search all CPUs in the domain -everytime. In fact, in some architectures, the searching ranges on +every time. In fact, in some architectures, the searching ranges on events are limited in the same socket or node where the CPU locates, -while the load balance on tick searchs all. +while the load balance on tick searches all. For example, assume CPU Z is relatively far from CPU X. Even if CPU Z is idle while CPU X and the siblings are busy, scheduler can't migrate @@ -601,7 +601,7 @@ its new cpuset, then the task will continue to use whatever subset of MPOL_BIND nodes are still allowed in the new cpuset. If the task was using MPOL_BIND and now none of its MPOL_BIND nodes are allowed in the new cpuset, then the task will be essentially treated as if it -was MPOL_BIND bound to the new cpuset (even though its numa placement, +was MPOL_BIND bound to the new cpuset (even though its NUMA placement, as queried by get_mempolicy(), doesn't change). If a task is moved from one cpuset to another, then the kernel will adjust the tasks memory placement, as above, the next time that the kernel attempts diff --git a/Documentation/cgroups/devices.txt b/Documentation/cgroups/devices.txt index 7cc6e6a6067..57ca4c89fe5 100644 --- a/Documentation/cgroups/devices.txt +++ b/Documentation/cgroups/devices.txt @@ -42,7 +42,7 @@ suffice, but we can decide the best way to adequately restrict movement as people get some experience with this. We may just want to require CAP_SYS_ADMIN, which at least is a separate bit from CAP_MKNOD. We may want to just refuse moving to a cgroup which -isn't a descendent of the current one. Or we may want to use +isn't a descendant of the current one. Or we may want to use CAP_MAC_ADMIN, since we really are trying to lock down root. CAP_SYS_ADMIN is needed to modify the whitelist or move another diff --git a/Documentation/cgroups/memcg_test.txt b/Documentation/cgroups/memcg_test.txt index 523a9c16c40..72db89ed060 100644 --- a/Documentation/cgroups/memcg_test.txt +++ b/Documentation/cgroups/memcg_test.txt @@ -1,5 +1,5 @@ Memory Resource Controller(Memcg) Implementation Memo. -Last Updated: 2009/1/19 +Last Updated: 2009/1/20 Base Kernel Version: based on 2.6.29-rc2. Because VM is getting complex (one of reasons is memcg...), memcg's behavior @@ -356,7 +356,25 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. (Shell-B) # move all tasks in /cgroup/test to /cgroup # /sbin/swapoff -a - # rmdir /test/cgroup + # rmdir /cgroup/test # kill malloc task. Of course, tmpfs v.s. swapoff test should be tested, too. + + 9.8 OOM-Killer + Out-of-memory caused by memcg's limit will kill tasks under + the memcg. When hierarchy is used, a task under hierarchy + will be killed by the kernel. + In this case, panic_on_oom shouldn't be invoked and tasks + in other groups shouldn't be killed. + + It's not difficult to cause OOM under memcg as following. + Case A) when you can swapoff + #swapoff -a + #echo 50M > /memory.limit_in_bytes + run 51M of malloc + + Case B) when you use mem+swap limitation. + #echo 50M > memory.limit_in_bytes + #echo 50M > memory.memsw.limit_in_bytes + run 51M of malloc diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index e1501964df1..a98a7fe7aab 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -302,7 +302,7 @@ will be charged as a new owner of it. unevictable - # of pages cannot be reclaimed.(mlocked etc) Below is depend on CONFIG_DEBUG_VM. - inactive_ratio - VM inernal parameter. (see mm/page_alloc.c) + inactive_ratio - VM internal parameter. (see mm/page_alloc.c) recent_rotated_anon - VM internal parameter. (see mm/vmscan.c) recent_rotated_file - VM internal parameter. (see mm/vmscan.c) recent_scanned_anon - VM internal parameter. (see mm/vmscan.c) diff --git a/Documentation/devices.txt b/Documentation/devices.txt index 62254d4510c..327de162475 100644 --- a/Documentation/devices.txt +++ b/Documentation/devices.txt @@ -1,7 +1,7 @@ LINUX ALLOCATED DEVICES (2.6+ version) - Maintained by Torben Mathiasen <device@lanana.org> + Maintained by Alan Cox <device@lanana.org> Last revised: 29 November 2006 @@ -67,6 +67,11 @@ up to date. Due to the number of registrations I have to maintain it in "batch mode", so there is likely additional registrations that haven't been listed yet. +Fourth, remember that Linux now has extensive support for dynamic allocation +of device numbering and can use sysfs and udev to handle the naming needs. +There are still some exceptions in the serial and boot device area. Before +asking for a device number make sure you actually need one. + Finally, sometimes I have to play "namespace police." Please don't be offended. I often get submissions for /dev names that would be bound to cause conflicts down the road. I am trying to avoid getting in a @@ -101,7 +106,7 @@ Your cooperation is appreciated. 0 = /dev/ram0 First RAM disk 1 = /dev/ram1 Second RAM disk ... - 250 = /dev/initrd Initial RAM disk {2.6} + 250 = /dev/initrd Initial RAM disk Older kernels had /dev/ramdisk (1, 1) here. /dev/initrd refers to a RAM disk which was preloaded @@ -340,7 +345,7 @@ Your cooperation is appreciated. 14 = /dev/touchscreen/ucb1x00 UCB 1x00 touchscreen 15 = /dev/touchscreen/mk712 MK712 touchscreen 128 = /dev/beep Fancy beep device - 129 = /dev/modreq Kernel module load request {2.6} + 129 = 130 = /dev/watchdog Watchdog timer port 131 = /dev/temperature Machine internal temperature 132 = /dev/hwtrap Hardware fault trap @@ -350,10 +355,10 @@ Your cooperation is appreciated. 139 = /dev/openprom SPARC OpenBoot PROM 140 = /dev/relay8 Berkshire Products Octal relay card 141 = /dev/relay16 Berkshire Products ISO-16 relay card - 142 = /dev/msr x86 model-specific registers {2.6} + 142 = 143 = /dev/pciconf PCI configuration space 144 = /dev/nvram Non-volatile configuration RAM - 145 = /dev/hfmodem Soundcard shortwave modem control {2.6} + 145 = /dev/hfmodem Soundcard shortwave modem control 146 = /dev/graphics Linux/SGI graphics device 147 = /dev/opengl Linux/SGI OpenGL pipe 148 = /dev/gfx Linux/SGI graphics effects device @@ -435,6 +440,9 @@ Your cooperation is appreciated. 228 = /dev/hpet HPET driver 229 = /dev/fuse Fuse (virtual filesystem in user-space) 230 = /dev/midishare MidiShare driver + 231 = /dev/snapshot System memory snapshot device + 232 = /dev/kvm Kernel-based virtual machine (hardware virtualization extensions) + 233 = /dev/kmview View-OS A process with a view 240-254 Reserved for local use 255 Reserved for MISC_DYNAMIC_MINOR @@ -466,10 +474,7 @@ Your cooperation is appreciated. The device names specified are proposed -- if there are "standard" names for these devices, please let me know. - 12 block MSCDEX CD-ROM callback support {2.6} - 0 = /dev/dos_cd0 First MSCDEX CD-ROM - 1 = /dev/dos_cd1 Second MSCDEX CD-ROM - ... + 12 block 13 char Input core 0 = /dev/input/js0 First joystick @@ -498,7 +503,7 @@ Your cooperation is appreciated. 2 = /dev/midi00 First MIDI port 3 = /dev/dsp Digital audio 4 = /dev/audio Sun-compatible digital audio - 6 = /dev/sndstat Sound card status information {2.6} + 6 = 7 = /dev/audioctl SPARC audio control device 8 = /dev/sequencer2 Sequencer -- alternate device 16 = /dev/mixer1 Second soundcard mixer control @@ -510,14 +515,7 @@ Your cooperation is appreciated. 34 = /dev/midi02 Third MIDI port 50 = /dev/midi03 Fourth MIDI port - 14 block BIOS harddrive callback support {2.6} - 0 = /dev/dos_hda First BIOS harddrive whole disk - 64 = /dev/dos_hdb Second BIOS harddrive whole disk - 128 = /dev/dos_hdc Third BIOS harddrive whole disk - 192 = /dev/dos_hdd Fourth BIOS harddrive whole disk - - Partitions are handled in the same way as IDE disks - (see major number 3). + 14 block 15 char Joystick 0 = /dev/js0 First analog joystick @@ -535,14 +533,14 @@ Your cooperation is appreciated. 16 block GoldStar CD-ROM 0 = /dev/gscd GoldStar CD-ROM - 17 char Chase serial card + 17 char OBSOLETE (was Chase serial card) 0 = /dev/ttyH0 First Chase port 1 = /dev/ttyH1 Second Chase port ... 17 block Optics Storage CD-ROM 0 = /dev/optcd Optics Storage CD-ROM - 18 char Chase serial card - alternate devices + 18 char OBSOLETE (was Chase serial card - alternate devices) 0 = /dev/cuh0 Callout device for ttyH0 1 = /dev/cuh1 Callout device for ttyH1 ... @@ -644,8 +642,7 @@ Your cooperation is appreciated. 2 = /dev/sbpcd2 Panasonic CD-ROM controller 0 unit 2 3 = /dev/sbpcd3 Panasonic CD-ROM controller 0 unit 3 - 26 char Quanta WinVision frame grabber {2.6} - 0 = /dev/wvisfgrab Quanta WinVision frame grabber + 26 char 26 block Second Matsushita (Panasonic/SoundBlaster) CD-ROM 0 = /dev/sbpcd4 Panasonic CD-ROM controller 1 unit 0 @@ -872,7 +869,7 @@ Your cooperation is appreciated. and "user level packet I/O." This board is also accessible as a standard networking "eth" device. - 38 block Reserved for Linux/AP+ + 38 block OBSOLETE (was Linux/AP+) 39 char ML-16P experimental I/O board 0 = /dev/ml16pa-a0 First card, first analog channel @@ -892,29 +889,16 @@ Your cooperation is appreciated. 50 = /dev/ml16pb-c1 Second card, second counter/timer 51 = /dev/ml16pb-c2 Second card, third counter/timer ... - 39 block Reserved for Linux/AP+ + 39 block - 40 char Matrox Meteor frame grabber {2.6} - 0 = /dev/mmetfgrab Matrox Meteor frame grabber + 40 char - 40 block Syquest EZ135 parallel port removable drive - 0 = /dev/eza Parallel EZ135 drive, whole disk - - This device is obsolete and will be removed in a - future version of Linux. It has been replaced with - the parallel port IDE disk driver at major number 45. - Partitions are handled in the same way as IDE disks - (see major number 3). + 40 block 41 char Yet Another Micro Monitor 0 = /dev/yamm Yet Another Micro Monitor - 41 block MicroSolutions BackPack parallel port CD-ROM - 0 = /dev/bpcd BackPack CD-ROM - - This device is obsolete and will be removed in a - future version of Linux. It has been replaced with - the parallel port ATAPI CD-ROM driver at major number 46. + 41 block 42 char Demo/sample use @@ -1681,13 +1665,7 @@ Your cooperation is appreciated. disks (see major number 3) except that the limit on partitions is 15. - 93 char IBM Smart Capture Card frame grabber {2.6} - 0 = /dev/iscc0 First Smart Capture Card - 1 = /dev/iscc1 Second Smart Capture Card - ... - 128 = /dev/isccctl0 First Smart Capture Card control - 129 = /dev/isccctl1 Second Smart Capture Card control - ... + 93 char 93 block NAND Flash Translation Layer filesystem 0 = /dev/nftla First NFTL layer @@ -1695,10 +1673,7 @@ Your cooperation is appreciated. ... 240 = /dev/nftlp 16th NTFL layer - 94 char miroVIDEO DC10/30 capture/playback device {2.6} - 0 = /dev/dcxx0 First capture card - 1 = /dev/dcxx1 Second capture card - ... + 94 char 94 block IBM S/390 DASD block storage 0 = /dev/dasda First DASD device, major @@ -1791,11 +1766,7 @@ Your cooperation is appreciated. ... 15 = /dev/amiraid/ar?p15 15th partition -102 char Philips SAA5249 Teletext signal decoder {2.6} - 0 = /dev/tlk0 First Teletext decoder - 1 = /dev/tlk1 Second Teletext decoder - 2 = /dev/tlk2 Third Teletext decoder - 3 = /dev/tlk3 Fourth Teletext decoder +102 char 102 block Compressed block device 0 = /dev/cbd/a First compressed block device, whole device @@ -1916,10 +1887,7 @@ Your cooperation is appreciated. DAC960 (see major number 48) except that the limit on partitions is 15. -111 char Philips SAA7146-based audio/video card {2.6} - 0 = /dev/av0 First A/V card - 1 = /dev/av1 Second A/V card - ... +111 char 111 block Compaq Next Generation Drive Array, eighth controller 0 = /dev/cciss/c7d0 First logical drive, whole disk @@ -2079,8 +2047,8 @@ Your cooperation is appreciated. ... 119 char VMware virtual network control - 0 = /dev/vmnet0 1st virtual network - 1 = /dev/vmnet1 2nd virtual network + 0 = /dev/vnet0 1st virtual network + 1 = /dev/vnet1 2nd virtual network ... 120-127 char LOCAL/EXPERIMENTAL USE @@ -2450,7 +2418,7 @@ Your cooperation is appreciated. 2 = /dev/raw/raw2 Second raw I/O device ... -163 char UNASSIGNED (was Radio Tech BIM-XXX-RS232 radio modem - see 51) +163 char 164 char Chase Research AT/PCI-Fast serial card 0 = /dev/ttyCH0 AT/PCI-Fast board 0, port 0 @@ -2542,6 +2510,12 @@ Your cooperation is appreciated. 1 = /dev/clanvi1 Second cLAN adapter ... +179 block MMC block devices + 0 = /dev/mmcblk0 First SD/MMC card + 1 = /dev/mmcblk0p1 First partition on first MMC card + 8 = /dev/mmcblk1 Second SD/MMC card + ... + 179 char CCube DVXChip-based PCI products 0 = /dev/dvxirq0 First DVX device 1 = /dev/dvxirq1 Second DVX device @@ -2560,6 +2534,9 @@ Your cooperation is appreciated. 96 = /dev/usb/hiddev0 1st USB HID device ... 111 = /dev/usb/hiddev15 16th USB HID device + 112 = /dev/usb/auer0 1st auerswald ISDN device + ... + 127 = /dev/usb/auer15 16th auerswald ISDN device 128 = /dev/usb/brlvgr0 First Braille Voyager device ... 131 = /dev/usb/brlvgr3 Fourth Braille Voyager device @@ -2810,6 +2787,16 @@ Your cooperation is appreciated. ... 190 = /dev/ttyUL3 Xilinx uartlite - port 3 191 = /dev/xvc0 Xen virtual console - port 0 + 192 = /dev/ttyPZ0 pmac_zilog - port 0 + ... + 195 = /dev/ttyPZ3 pmac_zilog - port 3 + 196 = /dev/ttyTX0 TX39/49 serial port 0 + ... + 204 = /dev/ttyTX7 TX39/49 serial port 7 + 205 = /dev/ttySC0 SC26xx serial port 0 + 206 = /dev/ttySC1 SC26xx serial port 1 + 207 = /dev/ttySC2 SC26xx serial port 2 + 208 = /dev/ttySC3 SC26xx serial port 3 205 char Low-density serial ports (alternate device) 0 = /dev/culu0 Callout device for ttyLU0 @@ -3145,6 +3132,14 @@ Your cooperation is appreciated. 1 = /dev/blockrom1 Second ROM card's translation layer interface ... +259 block Block Extended Major + Used dynamically to hold additional partition minor + numbers and allow large numbers of partitions per device + +259 char FPGA configuration interfaces + 0 = /dev/icap0 First Xilinx internal configuration + 1 = /dev/icap1 Second Xilinx internal configuration + 260 char OSD (Object-based-device) SCSI Device 0 = /dev/osd0 First OSD Device 1 = /dev/osd1 Second OSD Device diff --git a/Documentation/fb/00-INDEX b/Documentation/fb/00-INDEX index caabbd395e6..a618fd99c9f 100644 --- a/Documentation/fb/00-INDEX +++ b/Documentation/fb/00-INDEX @@ -11,8 +11,6 @@ aty128fb.txt - info on the ATI Rage128 frame buffer driver. cirrusfb.txt - info on the driver for Cirrus Logic chipsets. -cyblafb/ - - directory with documentation files related to the cyblafb driver. deferred_io.txt - an introduction to deferred IO. fbcon.txt diff --git a/Documentation/fb/cyblafb/bugs b/Documentation/fb/cyblafb/bugs deleted file mode 100644 index 9443a6d72cd..00000000000 --- a/Documentation/fb/cyblafb/bugs +++ /dev/null @@ -1,13 +0,0 @@ -Bugs -==== - -I currently don't know of any bug. Please do send reports to: - - linux-fbdev-devel@lists.sourceforge.net - - Knut_Petersen@t-online.de. - - -Untested features -================= - -All LCD stuff is untested. If it worked in tridentfb, it should work in -cyblafb. Please test and report the results to Knut_Petersen@t-online.de. diff --git a/Documentation/fb/cyblafb/credits b/Documentation/fb/cyblafb/credits deleted file mode 100644 index 0eb3b443dc2..00000000000 --- a/Documentation/fb/cyblafb/credits +++ /dev/null @@ -1,7 +0,0 @@ -Thanks to -========= - * Alan Hourihane, for writing the X trident driver - * Jani Monoses, for writing the tridentfb driver - * Antonino A. Daplas, for review of the first published - version of cyblafb and some code - * Jochen Hein, for testing and a helpfull bug report diff --git a/Documentation/fb/cyblafb/documentation b/Documentation/fb/cyblafb/documentation deleted file mode 100644 index bb1aac04842..00000000000 --- a/Documentation/fb/cyblafb/documentation +++ /dev/null @@ -1,17 +0,0 @@ -Available Documentation -======================= - -Apollo PLE 133 Chipset VT8601A North Bridge Datasheet, Rev. 1.82, October 22, -2001, available from VIA: - - http://www.viavpsd.com/product/6/15/DS8601A182.pdf - -The datasheet is incomplete, some registers that need to be programmed are not -explained at all and important bits are listed as "reserved". But you really -need the datasheet to understand the code. "p. xxx" comments refer to page -numbers of this document. - -XFree/XOrg drivers are available and of good quality, looking at the code -there is a good idea if the datasheet does not provide enough information -or if the datasheet seems to be wrong. - diff --git a/Documentation/fb/cyblafb/fb.modes b/Documentation/fb/cyblafb/fb.modes deleted file mode 100644 index fe0e5223ba8..00000000000 --- a/Documentation/fb/cyblafb/fb.modes +++ /dev/null @@ -1,154 +0,0 @@ -# -# Sample fb.modes file -# -# Provides an incomplete list of working modes for -# the cyberblade/i1 graphics core. -# -# The value 4294967256 is used instead of -40. Of course, -40 is not -# a really reasonable value, but chip design does not always follow -# logic. Believe me, it's ok, and it's the way the BIOS does it. -# -# fbset requires 4294967256 in fb.modes and -40 as an argument to -# the -t parameter. That's also not too reasonable, and it might change -# in the future or might even be differt for your current version. -# - -mode "640x480-50" - geometry 640 480 2048 4096 8 - timings 47619 4294967256 24 17 0 216 3 -endmode - -mode "640x480-60" - geometry 640 480 2048 4096 8 - timings 39682 4294967256 24 17 0 216 3 -endmode - -mode "640x480-70" - geometry 640 480 2048 4096 8 - timings 34013 4294967256 24 17 0 216 3 -endmode - -mode "640x480-72" - geometry 640 480 2048 4096 8 - timings 33068 4294967256 24 17 0 216 3 -endmode - -mode "640x480-75" - geometry 640 480 2048 4096 8 - timings 31746 4294967256 24 17 0 216 3 -endmode - -mode "640x480-80" - geometry 640 480 2048 4096 8 - timings 29761 4294967256 24 17 0 216 3 -endmode - -mode "640x480-85" - geometry 640 480 2048 4096 8 - timings 28011 4294967256 24 17 0 216 3 -endmode - -mode "800x600-50" - geometry 800 600 2048 4096 8 - timings 30303 96 24 14 0 136 11 -endmode - -mode "800x600-60" - geometry 800 600 2048 4096 8 - timings 25252 96 24 14 0 136 11 -endmode - -mode "800x600-70" - geometry 800 600 2048 4096 8 - timings 21645 96 24 14 0 136 11 -endmode - -mode "800x600-72" - geometry 800 600 2048 4096 8 - timings 21043 96 24 14 0 136 11 -endmode - -mode "800x600-75" - geometry 800 600 2048 4096 8 - timings 20202 96 24 14 0 136 11 -endmode - -mode "800x600-80" - geometry 800 600 2048 4096 8 - timings 18939 96 24 14 0 136 11 -endmode - -mode "800x600-85" - geometry 800 600 2048 4096 8 - timings 17825 96 24 14 0 136 11 -endmode - -mode "1024x768-50" - geometry 1024 768 2048 4096 8 - timings 19054 144 24 29 0 120 3 -endmode - -mode "1024x768-60" - geometry 1024 768 2048 4096 8 - timings 15880 144 24 29 0 120 3 -endmode - -mode "1024x768-70" - geometry 1024 768 2048 4096 8 - timings 13610 144 24 29 0 120 3 -endmode - -mode "1024x768-72" - geometry 1024 768 2048 4096 8 - timings 13232 144 24 29 0 120 3 -endmode - -mode "1024x768-75" - geometry 1024 768 2048 4096 8 - timings 12703 144 24 29 0 120 3 -endmode - -mode "1024x768-80" - geometry 1024 768 2048 4096 8 - timings 11910 144 24 29 0 120 3 -endmode - -mode "1024x768-85" - geometry 1024 768 2048 4096 8 - timings 11209 144 24 29 0 120 3 -endmode - -mode "1280x1024-50" - geometry 1280 1024 2048 4096 8 - timings 11114 232 16 39 0 160 3 -endmode - -mode "1280x1024-60" - geometry 1280 1024 2048 4096 8 - timings 9262 232 16 39 0 160 3 -endmode - -mode "1280x1024-70" - geometry 1280 1024 2048 4096 8 - timings 7939 232 16 39 0 160 3 -endmode - -mode "1280x1024-72" - geometry 1280 1024 2048 4096 8 - timings 7719 232 16 39 0 160 3 -endmode - -mode "1280x1024-75" - geometry 1280 1024 2048 4096 8 - timings 7410 232 16 39 0 160 3 -endmode - -mode "1280x1024-80" - geometry 1280 1024 2048 4096 8 - timings 6946 232 16 39 0 160 3 -endmode - -mode "1280x1024-85" - geometry 1280 1024 2048 4096 8 - timings 6538 232 16 39 0 160 3 -endmode diff --git a/Documentation/fb/cyblafb/performance b/Documentation/fb/cyblafb/performance deleted file mode 100644 index 8d15d5dfc6b..00000000000 --- a/Documentation/fb/cyblafb/performance +++ /dev/null @@ -1,79 +0,0 @@ -Speed -===== - -CyBlaFB is much faster than tridentfb and vesafb. Compare the performance data -for mode 1280x1024-[8,16,32]@61 Hz. - -Test 1: Cat a file with 2000 lines of 0 characters. -Test 2: Cat a file with 2000 lines of 80 characters. -Test 3: Cat a file with 2000 lines of 160 characters. - -All values show system time use in seconds, kernel 2.6.12 was used for -the measurements. 2.6.13 is a bit slower, 2.6.14 hopefully will include a -patch that speeds up kernel bitblitting a lot ( > 20%). - -+-----------+-----------------------------------------------------+ -| | not accelerated | -| TRIDENTFB +-----------------+-----------------+-----------------+ -| of 2.6.12 | 8 bpp | 16 bpp | 32 bpp | -| | noypan | ypan | noypan | ypan | noypan | ypan | -+-----------+--------+--------+--------+--------+--------+--------+ -| Test 1 | 4.31 | 4.33 | 6.05 | 12.81 | ---- | ---- | -| Test 2 | 67.94 | 5.44 | 123.16 | 14.79 | ---- | ---- | -| Test 3 | 131.36 | 6.55 | 240.12 | 16.76 | ---- | ---- | -+-----------+--------+--------+--------+--------+--------+--------+ -| Comments | | | completely bro- | -| | | | ken, monitor | -| | | | switches off | -+-----------+-----------------+-----------------+-----------------+ - - -+-----------+-----------------------------------------------------+ -| | accelerated | -| TRIDENTFB +-----------------+-----------------+-----------------+ -| of 2.6.12 | 8 bpp | 16 bpp | 32 bpp | -| | noypan | ypan | noypan | ypan | noypan | ypan | -+-----------+--------+--------+--------+--------+--------+--------+ -| Test 1 | ---- | ---- | 20.62 | 1.22 | ---- | ---- | -| Test 2 | ---- | ---- | 22.61 | 3.19 | ---- | ---- | -| Test 3 | ---- | ---- | 24.59 | 5.16 | ---- | ---- | -+-----------+--------+--------+--------+--------+--------+--------+ -| Comments | broken, writing | broken, ok only | completely bro- | -| | to wrong places | if bgcolor is | ken, monitor | -| | on screen + bug | black, bug in | switches off | -| | in fillrect() | fillrect() | | -+-----------+-----------------+-----------------+-----------------+ - - -+-----------+-----------------------------------------------------+ -| | not accelerated | -| VESAFB +-----------------+-----------------+-----------------+ -| of 2.6.12 | 8 bpp | 16 bpp | 32 bpp | -| | noypan | ypan | noypan | ypan | noypan | ypan | -+-----------+--------+--------+--------+--------+--------+--------+ -| Test 1 | 4.26 | 3.76 | 5.99 | 7.23 | ---- | ---- | -| Test 2 | 65.65 | 4.89 | 120.88 | 9.08 | ---- | ---- | -| Test 3 | 126.91 | 5.94 | 235.77 | 11.03 | ---- | ---- | -+-----------+--------+--------+--------+--------+--------+--------+ -| Comments | vga=0x307 | vga=0x31a | vga=0x31b not | -| | fh=80kHz | fh=80kHz | supported by | -| | fv=75kHz | fv=75kHz | video BIOS and | -| | | | hardware | -+-----------+-----------------+-----------------+-----------------+ - - -+-----------+-----------------------------------------------------+ -| | accelerated | -| CYBLAFB +-----------------+-----------------+-----------------+ -| | 8 bpp | 16 bpp | 32 bpp | -| | noypan | ypan | noypan | ypan | noypan | ypan | -+-----------+--------+--------+--------+--------+--------+--------+ -| Test 1 | 8.02 | 0.23 | 19.04 | 0.61 | 57.12 | 2.74 | -| Test 2 | 8.38 | 0.55 | 19.39 | 0.92 | 57.54 | 3.13 | -| Test 3 | 8.73 | 0.86 | 19.74 | 1.24 | 57.95 | 3.51 | -+-----------+--------+--------+--------+--------+--------+--------+ -| Comments | | | | -| | | | | -| | | | | -| | | | | -+-----------+-----------------+-----------------+-----------------+ diff --git a/Documentation/fb/cyblafb/todo b/Documentation/fb/cyblafb/todo deleted file mode 100644 index c5f6d0eae54..00000000000 --- a/Documentation/fb/cyblafb/todo +++ /dev/null @@ -1,31 +0,0 @@ -TODO / Missing features -======================= - -Verify LCD stuff "stretch" and "center" options are - completely untested ... this code needs to be - verified. As I don't have access to such - hardware, please contact me if you are - willing run some tests. - -Interlaced video modes The reason that interleaved - modes are disabled is that I do not know - the meaning of the vertical interlace - parameter. Also the datasheet mentions a - bit d8 of a horizontal interlace parameter, - but nowhere the lower 8 bits. Please help - if you can. - -low-res double scan modes Who needs it? - -accelerated color blitting Who needs it? The console driver does use color - blitting for nothing but drawing the penguine, - everything else is done using color expanding - blitting of 1bpp character bitmaps. - -ioctls Who needs it? - -TV-out Will be done later. Use "vga= " at boot time - to set a suitable video mode. - -??? Feel free to contact me if you have any - feature requests diff --git a/Documentation/fb/cyblafb/usage b/Documentation/fb/cyblafb/usage deleted file mode 100644 index a39bb3d402a..00000000000 --- a/Documentation/fb/cyblafb/usage +++ /dev/null @@ -1,217 +0,0 @@ -CyBlaFB is a framebuffer driver for the Cyberblade/i1 graphics core integrated -into the VIA Apollo PLE133 (aka vt8601) south bridge. It is developed and -tested using a VIA EPIA 5000 board. - -Cyblafb - compiled into the kernel or as a module? -================================================== - -You might compile cyblafb either as a module or compile it permanently into the -kernel. - -Unless you have a real reason to do so you should not compile both vesafb and -cyblafb permanently into the kernel. It's possible and it helps during the -developement cycle, but it's useless and will at least block some otherwise -usefull memory for ordinary users. - -Selecting Modes -=============== - - Startup Mode - ============ - - First of all, you might use the "vga=???" boot parameter as it is - documented in vesafb.txt and svga.txt. Cyblafb will detect the video - mode selected and will use the geometry and timings found by - inspecting the hardware registers. - - video=cyblafb vga=0x317 - - Alternatively you might use a combination of the mode, ref and bpp - parameters. If you compiled the driver into the kernel, add something - like this to the kernel command line: - - video=cyblafb:1280x1024,bpp=16,ref=50 ... - - If you compiled the driver as a module, the same mode would be - selected by the following command: - - modprobe cyblafb mode=1280x1024 bpp=16 ref=50 ... - - None of the modes possible to select as startup modes are affected by - the problems described at the end of the next subsection. - - For all startup modes cyblafb chooses a virtual x resolution of 2048, - the only exception is mode 1280x1024 in combination with 32 bpp. This - allows ywrap scrolling for all those modes if rotation is 0 or 2, and - also fast scrolling if rotation is 1 or 3. The default virtual y reso- - lution is 4096 for bpp == 8, 2048 for bpp==16 and 1024 for bpp == 32, - again with the only exception of 1280x1024 at 32 bpp. - - Please do set your video memory size to 8 Mb in the Bios setup. Other - values will work, but performace is decreased for a lot of modes. - - Mode changes using fbset - ======================== - - You might use fbset to change the video mode, see "man fbset". Cyblafb - generally does assume that you know what you are doing. But it does - some checks, especially those that are needed to prevent you from - damaging your hardware. - - - only 8, 16, 24 and 32 bpp video modes are accepted - - interlaced video modes are not accepted - - double scan video modes are not accepted - - if a flat panel is found, cyblafb does not allow you - to program a resolution higher than the physical - resolution of the flat panel monitor - - cyblafb does not allow vclk to exceed 230 MHz. As 32 bpp - and (currently) 24 bit modes use a doubled vclk internally, - the dotclock limit as seen by fbset is 115 MHz for those - modes and 230 MHz for 8 and 16 bpp modes. - - cyblafb will allow you to select very high resolutions as - long as the hardware can be programmed to these modes. The - documented limit 1600x1200 is not enforced, but don't expect - perfect signal quality. - - Any request that violates the rules given above will be either changed - to something the hardware supports or an error value will be returned. - - If you program a virtual y resolution higher than the hardware limit, - cyblafb will silently decrease that value to the highest possible - value. The same is true for a virtual x resolution that is not - supported by the hardware. Cyblafb tries to adapt vyres first because - vxres decides if ywrap scrolling is possible or not. - - Attempts to disable acceleration are ignored, I believe that this is - safe. - - Some video modes that should work do not work as expected. If you use - the standard fb.modes, fbset 640x480-60 will program that mode, but - you will see a vertical area, about two characters wide, with only - much darker characters than the other characters on the screen. - Cyblafb does allow that mode to be set, as it does not violate the - official specifications. It would need a lot of code to reliably sort - out all invalid modes, playing around with the margin values will - give a valid mode quickly. And if cyblafb would detect such an invalid - mode, should it silently alter the requested values or should it - report an error? Both options have some pros and cons. As stated - above, none of the startup modes are affected, and if you set - verbosity to 1 or higher, cyblafb will print the fbset command that - would be needed to program that mode using fbset. - - -Other Parameters -================ - - -crt don't autodetect, assume monitor connected to - standard VGA connector - -fp don't autodetect, assume flat panel display - connected to flat panel monitor interface - -nativex inform driver about native x resolution of - flat panel monitor connected to special - interface (should be autodetected) - -stretch stretch image to adapt low resolution modes to - higer resolutions of flat panel monitors - connected to special interface - -center center image to adapt low resolution modes to - higer resolutions of flat panel monitors - connected to special interface - -memsize use if autodetected memsize is wrong ... - should never be necessary - -nopcirr disable PCI read retry -nopciwr disable PCI write retry -nopcirb disable PCI read bursts -nopciwb disable PCI write bursts - -bpp bpp for specified modes - valid values: 8 || 16 || 24 || 32 - -ref refresh rate for specified mode - valid values: 50 <= ref <= 85 - -mode 640x480 or 800x600 or 1024x768 or 1280x1024 - if not specified, the startup mode will be detected - and used, so you might also use the vga=??? parameter - described in vesafb.txt. If you do not specify a mode, - bpp and ref parameters are ignored. - -verbosity 0 is the default, increase to at least 2 for every - bug report! - -Development hints -================= - -It's much faster do compile a module and to load the new version after -unloading the old module than to compile a new kernel and to reboot. So if you -try to work on cyblafb, it might be a good idea to use cyblafb as a module. -In real life, fast often means dangerous, and that's also the case here. If -you introduce a serious bug when cyblafb is compiled into the kernel, the -kernel will lock or oops with a high probability before the file system is -mounted, and the danger for your data is low. If you load a broken own version -of cyblafb on a running system, the danger for the integrity of the file -system is much higher as you might need a hard reset afterwards. Decide -yourself. - -Module unloading, the vfb method -================================ - -If you want to unload/reload cyblafb using the virtual framebuffer, you need -to enable vfb support in the kernel first. After that, load the modules as -shown below: - - modprobe vfb vfb_enable=1 - modprobe fbcon - modprobe cyblafb - fbset -fb /dev/fb1 1280x1024-60 -vyres 2662 - con2fb /dev/fb1 /dev/tty1 - ... - -If you now made some changes to cyblafb and want to reload it, you might do it -as show below: - - con2fb /dev/fb0 /dev/tty1 - ... - rmmod cyblafb - modprobe cyblafb - con2fb /dev/fb1 /dev/tty1 - ... - -Of course, you might choose another mode, and most certainly you also want to -map some other /dev/tty* to the real framebuffer device. You might also choose -to compile fbcon as a kernel module or place it permanently in the kernel. - -I do not know of any way to unload fbcon, and fbcon will prevent the -framebuffer device loaded first from unloading. [If there is a way, then -please add a description here!] - -Module unloading, the vesafb method -=================================== - -Configure the kernel: - - <*> Support for frame buffer devices - [*] VESA VGA graphics support - <M> Cyberblade/i1 support - -Add e.g. "video=vesafb:ypan vga=0x307" to the kernel parameters. The ypan -parameter is important, choose any vga parameter you like as long as it is -a graphics mode. - -After booting, load cyblafb without any mode and bpp parameter and assign -cyblafb to individual ttys using con2fb, e.g.: - - modprobe cyblafb - con2fb /dev/fb1 /dev/tty1 - -Unloading cyblafb works without problems after you assign vesafb to all -ttys again, e.g.: - - con2fb /dev/fb0 /dev/tty1 - rmmod cyblafb diff --git a/Documentation/fb/cyblafb/whatsnew b/Documentation/fb/cyblafb/whatsnew deleted file mode 100644 index 76c07a26e04..00000000000 --- a/Documentation/fb/cyblafb/whatsnew +++ /dev/null @@ -1,29 +0,0 @@ -0.62 -==== - - - the vesafb parameter has been removed as I decided to allow the - feature without any special parameter. - - - Cyblafb does not use the vga style of panning any longer, now the - "right view" register in the graphics engine IO space is used. Without - that change it was impossible to use all available memory, and without - access to all available memory it is impossible to ywrap. - - - The imageblit function now uses hardware acceleration for all font - widths. Hardware blitting across pixel column 2048 is broken in the - cyberblade/i1 graphics core, but we work around that hardware bug. - - - modes with vxres != xres are supported now. - - - ywrap scrolling is supported now and the default. This is a big - performance gain. - - - default video modes use vyres > yres and vxres > xres to allow - almost optimal scrolling speed for normal and rotated screens - - - some features mainly usefull for debugging the upper layers of the - framebuffer system have been added, have a look at the code - - - fixed: Oops after unloading cyblafb when reading /proc/io* - - - we work around some bugs of the higher framebuffer layers. diff --git a/Documentation/fb/cyblafb/whycyblafb b/Documentation/fb/cyblafb/whycyblafb deleted file mode 100644 index a123bc11e69..00000000000 --- a/Documentation/fb/cyblafb/whycyblafb +++ /dev/null @@ -1,85 +0,0 @@ -I tried the following framebuffer drivers: - - - TRIDENTFB is full of bugs. Acceleration is broken for Blade3D - graphics cores like the cyberblade/i1. It claims to support a great - number of devices, but documentation for most of these devices is - unfortunately not available. There is _no_ reason to use tridentfb - for cyberblade/i1 + CRT users. VESAFB is faster, and the one - advantage, mode switching, is broken in tridentfb. - - - VESAFB is used by many distributions as a standard. Vesafb does - not support mode switching. VESAFB is a bit faster than the working - configurations of TRIDENTFB, but it is still too slow, even if you - use ypan. - - - EPIAFB (you'll find it on sourceforge) supports the Cyberblade/i1 - graphics core, but it still has serious bugs and developement seems - to have stopped. This is the one driver with TV-out support. If you - do need this feature, try epiafb. - -None of these drivers was a real option for me. - -I believe that is unreasonable to change code that announces to support 20 -devices if I only have more or less sufficient documentation for exactly one -of these. The risk of breaking device foo while fixing device bar is too high. - -So I decided to start CyBlaFB as a stripped down tridentfb. - -All code specific to other Trident chips has been removed. After that there -were a lot of cosmetic changes to increase the readability of the code. All -register names were changed to those mnemonics used in the datasheet. Function -and macro names were changed if they hindered easy understanding of the code. - -After that I debugged the code and implemented some new features. I'll try to -give a little summary of the main changes: - - - calculation of vertical and horizontal timings was fixed - - - video signal quality has been improved dramatically - - - acceleration: - - - fillrect and copyarea were fixed and reenabled - - - color expanding imageblit was newly implemented, color - imageblit (only used to draw the penguine) still uses the - generic code. - - - init of the acceleration engine was improved and moved to a - place where it really works ... - - - sync function has a timeout now and tries to reset and - reinit the accel engine if necessary - - - fewer slow copyarea calls when doing ypan scrolling by using - undocumented bit d21 of screen start address stored in - CR2B[5]. BIOS does use it also, so this should be safe. - - - cyblafb rejects any attempt to set modes that would cause vclk - values above reasonable 230 MHz. 32bit modes use a clock - multiplicator of 2, so fbset does show the correct values for - pixclock but not for vclk in this case. The fbset limit is 115 MHz - for 32 bpp modes. - - - cyblafb rejects modes known to be broken or unimplemented (all - interlaced modes, all doublescan modes for now) - - - cyblafb now works independant of the video mode in effect at startup - time (tridentfb does not init all needed registers to reasonable - values) - - - switching between video modes does work reliably now - - - the first video mode now is the one selected on startup using the - vga=???? mechanism or any of - - 640x480, 800x600, 1024x768, 1280x1024 - - 8, 16, 24 or 32 bpp - - refresh between 50 Hz and 85 Hz, 1 Hz steps (1280x1024-32 - is limited to 63Hz) - - - pci retry and pci burst mode are settable (try to disable if you - experience latency problems) - - - built as a module cyblafb might be unloaded and reloaded using - the vfb module and con2vt or might be used together with vesafb - diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 5e02b83ac12..39246fc1125 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -255,6 +255,16 @@ Who: Jan Engelhardt <jengelh@computergmbh.de> --------------------------- +What: GPIO autorequest on gpio_direction_{input,output}() in gpiolib +When: February 2010 +Why: All callers should use explicit gpio_request()/gpio_free(). + The autorequest mechanism in gpiolib was provided mostly as a + migration aid for legacy GPIO interfaces (for SOC based GPIOs). + Those users have now largely migrated. Platforms implementing + the GPIO interfaces without using gpiolib will see no changes. +Who: David Brownell <dbrownell@users.sourceforge.net> +--------------------------- + What: b43 support for firmware revision < 410 When: The schedule was July 2008, but it was decided that we are going to keep the code as long as there are no major maintanance headaches. @@ -273,13 +283,6 @@ Who: Glauber Costa <gcosta@redhat.com> --------------------------- -What: remove HID compat support -When: 2.6.29 -Why: needed only as a temporary solution until distros fix themselves up -Who: Jiri Slaby <jirislaby@gmail.com> - ---------------------------- - What: print_fn_descriptor_symbol() When: October 2009 Why: The %pF vsprintf format provides the same functionality in a @@ -311,6 +314,18 @@ Who: Vlad Yasevich <vladislav.yasevich@hp.com> --------------------------- +What: Ability for non root users to shm_get hugetlb pages based on mlock + resource limits +When: 2.6.31 +Why: Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or + have CAP_IPC_LOCK to be able to allocate shm segments backed by + huge pages. The mlock based rlimit check to allow shm hugetlb is + inconsistent with mmap based allocations. Hence it is being + deprecated. +Who: Ravikiran Thirumalai <kiran@scalex86.org> + +--------------------------- + What: CONFIG_THERMAL_HWMON When: January 2009 Why: This option was introduced just to allow older lm-sensors userspace @@ -380,3 +395,35 @@ Why: The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t) have been kept around for migration reasons. After more than two years it's time to remove them finally Who: Thomas Gleixner <tglx@linutronix.de> + +--------------------------- + +What: fakephp and associated sysfs files in /sys/bus/pci/slots/ +When: 2011 +Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to + represent a machine's physical PCI slots. The change in semantics + had userspace implications, as the hotplug core no longer allowed + drivers to create multiple sysfs files per physical slot (required + for multi-function devices, e.g.). fakephp was seen as a developer's + tool only, and its interface changed. Too late, we learned that + there were some users of the fakephp interface. + + In 2.6.30, the original fakephp interface was restored. At the same + time, the PCI core gained the ability that fakephp provided, namely + function-level hot-remove and hot-add. + + Since the PCI core now provides the same functionality, exposed in: + + /sys/bus/pci/rescan + /sys/bus/pci/devices/.../remove + /sys/bus/pci/devices/.../rescan + + there is no functional reason to maintain fakephp as well. + + We will keep the existing module so that 'modprobe fakephp' will + present the old /sys/bus/pci/slots/... interface for compatibility, + but users are urged to migrate their applications to the API above. + + After a reasonable transition period, we will remove the legacy + fakephp interface. +Who: Alex Chiang <achiang@hp.com> diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 4e78ce67784..76efe5b71d7 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -505,7 +505,7 @@ prototypes: void (*open)(struct vm_area_struct*); void (*close)(struct vm_area_struct*); int (*fault)(struct vm_area_struct*, struct vm_fault *); - int (*page_mkwrite)(struct vm_area_struct *, struct page *); + int (*page_mkwrite)(struct vm_area_struct *, struct vm_fault *); int (*access)(struct vm_area_struct *, unsigned long, void*, int, int); locking rules: diff --git a/Documentation/filesystems/caching/backend-api.txt b/Documentation/filesystems/caching/backend-api.txt new file mode 100644 index 00000000000..382d52cdaf2 --- /dev/null +++ b/Documentation/filesystems/caching/backend-api.txt @@ -0,0 +1,658 @@ + ========================== + FS-CACHE CACHE BACKEND API + ========================== + +The FS-Cache system provides an API by which actual caches can be supplied to +FS-Cache for it to then serve out to network filesystems and other interested +parties. + +This API is declared in <linux/fscache-cache.h>. + + +==================================== +INITIALISING AND REGISTERING A CACHE +==================================== + +To start off, a cache definition must be initialised and registered for each +cache the backend wants to make available. For instance, CacheFS does this in +the fill_super() operation on mounting. + +The cache definition (struct fscache_cache) should be initialised by calling: + + void fscache_init_cache(struct fscache_cache *cache, + struct fscache_cache_ops *ops, + const char *idfmt, + ...); + +Where: + + (*) "cache" is a pointer to the cache definition; + + (*) "ops" is a pointer to the table of operations that the backend supports on + this cache; and + + (*) "idfmt" is a format and printf-style arguments for constructing a label + for the cache. + + +The cache should then be registered with FS-Cache by passing a pointer to the +previously initialised cache definition to: + + int fscache_add_cache(struct fscache_cache *cache, + struct fscache_object *fsdef, + const char *tagname); + +Two extra arguments should also be supplied: + + (*) "fsdef" which should point to the object representation for the FS-Cache + master index in this cache. Netfs primary index entries will be created + here. FS-Cache keeps the caller's reference to the index object if + successful and will release it upon withdrawal of the cache. + + (*) "tagname" which, if given, should be a text string naming this cache. If + this is NULL, the identifier will be used instead. For CacheFS, the + identifier is set to name the underlying block device and the tag can be + supplied by mount. + +This function may return -ENOMEM if it ran out of memory or -EEXIST if the tag +is already in use. 0 will be returned on success. + + +===================== +UNREGISTERING A CACHE +===================== + +A cache can be withdrawn from the system by calling this function with a +pointer to the cache definition: + + void fscache_withdraw_cache(struct fscache_cache *cache); + +In CacheFS's case, this is called by put_super(). + + +======== +SECURITY +======== + +The cache methods are executed one of two contexts: + + (1) that of the userspace process that issued the netfs operation that caused + the cache method to be invoked, or + + (2) that of one of the processes in the FS-Cache thread pool. + +In either case, this may not be an appropriate context in which to access the +cache. + +The calling process's fsuid, fsgid and SELinux security identities may need to +be masqueraded for the duration of the cache driver's access to the cache. +This is left to the cache to handle; FS-Cache makes no effort in this regard. + + +=================================== +CONTROL AND STATISTICS PRESENTATION +=================================== + +The cache may present data to the outside world through FS-Cache's interfaces +in sysfs and procfs - the former for control and the latter for statistics. + +A sysfs directory called /sys/fs/fscache/<cachetag>/ is created if CONFIG_SYSFS +is enabled. This is accessible through the kobject struct fscache_cache::kobj +and is for use by the cache as it sees fit. + + +======================== +RELEVANT DATA STRUCTURES +======================== + + (*) Index/Data file FS-Cache representation cookie: + + struct fscache_cookie { + struct fscache_object_def *def; + struct fscache_netfs *netfs; + void *netfs_data; + ... + }; + + The fields that might be of use to the backend describe the object + definition, the netfs definition and the netfs's data for this cookie. + The object definition contain functions supplied by the netfs for loading + and matching index entries; these are required to provide some of the + cache operations. + + + (*) In-cache object representation: + + struct fscache_object { + int debug_id; + enum { + FSCACHE_OBJECT_RECYCLING, + ... + } state; + spinlock_t lock + struct fscache_cache *cache; + struct fscache_cookie *cookie; + ... + }; + + Structures of this type should be allocated by the cache backend and + passed to FS-Cache when requested by the appropriate cache operation. In + the case of CacheFS, they're embedded in CacheFS's internal object + structures. + + The debug_id is a simple integer that can be used in debugging messages + that refer to a particular object. In such a case it should be printed + using "OBJ%x" to be consistent with FS-Cache. + + Each object contains a pointer to the cookie that represents the object it + is backing. An object should retired when put_object() is called if it is + in state FSCACHE_OBJECT_RECYCLING. The fscache_object struct should be + initialised by calling fscache_object_init(object). + + + (*) FS-Cache operation record: + + struct fscache_operation { + atomic_t usage; + struct fscache_object *object; + unsigned long flags; + #define FSCACHE_OP_EXCLUSIVE + void (*processor)(struct fscache_operation *op); + void (*release)(struct fscache_operation *op); + ... + }; + + FS-Cache has a pool of threads that it uses to give CPU time to the + various asynchronous operations that need to be done as part of driving + the cache. These are represented by the above structure. The processor + method is called to give the op CPU time, and the release method to get + rid of it when its usage count reaches 0. + + An operation can be made exclusive upon an object by setting the + appropriate flag before enqueuing it with fscache_enqueue_operation(). If + an operation needs more processing time, it should be enqueued again. + + + (*) FS-Cache retrieval operation record: + + struct fscache_retrieval { + struct fscache_operation op; + struct address_space *mapping; + struct list_head *to_do; + ... + }; + + A structure of this type is allocated by FS-Cache to record retrieval and + allocation requests made by the netfs. This struct is then passed to the + backend to do the operation. The backend may get extra refs to it by + calling fscache_get_retrieval() and refs may be discarded by calling + fscache_put_retrieval(). + + A retrieval operation can be used by the backend to do retrieval work. To + do this, the retrieval->op.processor method pointer should be set + appropriately by the backend and fscache_enqueue_retrieval() called to + submit it to the thread pool. CacheFiles, for example, uses this to queue + page examination when it detects PG_lock being cleared. + + The to_do field is an empty list available for the cache backend to use as + it sees fit. + + + (*) FS-Cache storage operation record: + + struct fscache_storage { + struct fscache_operation op; + pgoff_t store_limit; + ... + }; + + A structure of this type is allocated by FS-Cache to record outstanding + writes to be made. FS-Cache itself enqueues this operation and invokes + the write_page() method on the object at appropriate times to effect + storage. + + +================ +CACHE OPERATIONS +================ + +The cache backend provides FS-Cache with a table of operations that can be +performed on the denizens of the cache. These are held in a structure of type: + + struct fscache_cache_ops + + (*) Name of cache provider [mandatory]: + + const char *name + + This isn't strictly an operation, but should be pointed at a string naming + the backend. + + + (*) Allocate a new object [mandatory]: + + struct fscache_object *(*alloc_object)(struct fscache_cache *cache, + struct fscache_cookie *cookie) + + This method is used to allocate a cache object representation to back a + cookie in a particular cache. fscache_object_init() should be called on + the object to initialise it prior to returning. + + This function may also be used to parse the index key to be used for + multiple lookup calls to turn it into a more convenient form. FS-Cache + will call the lookup_complete() method to allow the cache to release the + form once lookup is complete or aborted. + + + (*) Look up and create object [mandatory]: + + void (*lookup_object)(struct fscache_object *object) + + This method is used to look up an object, given that the object is already + allocated and attached to the cookie. This should instantiate that object + in the cache if it can. + + The method should call fscache_object_lookup_negative() as soon as + possible if it determines the object doesn't exist in the cache. If the + object is found to exist and the netfs indicates that it is valid then + fscache_obtained_object() should be called once the object is in a + position to have data stored in it. Similarly, fscache_obtained_object() + should also be called once a non-present object has been created. + + If a lookup error occurs, fscache_object_lookup_error() should be called + to abort the lookup of that object. + + + (*) Release lookup data [mandatory]: + + void (*lookup_complete)(struct fscache_object *object) + + This method is called to ask the cache to release any resources it was + using to perform a lookup. + + + (*) Increment object refcount [mandatory]: + + struct fscache_object *(*grab_object)(struct fscache_object *object) + + This method is called to increment the reference count on an object. It + may fail (for instance if the cache is being withdrawn) by returning NULL. + It should return the object pointer if successful. + + + (*) Lock/Unlock object [mandatory]: + + void (*lock_object)(struct fscache_object *object) + void (*unlock_object)(struct fscache_object *object) + + These methods are used to exclusively lock an object. It must be possible + to schedule with the lock held, so a spinlock isn't sufficient. + + + (*) Pin/Unpin object [optional]: + + int (*pin_object)(struct fscache_object *object) + void (*unpin_object)(struct fscache_object *object) + + These methods are used to pin an object into the cache. Once pinned an + object cannot be reclaimed to make space. Return -ENOSPC if there's not + enough space in the cache to permit this. + + + (*) Update object [mandatory]: + + int (*update_object)(struct fscache_object *object) + + This is called to update the index entry for the specified object. The + new information should be in object->cookie->netfs_data. This can be + obtained by calling object->cookie->def->get_aux()/get_attr(). + + + (*) Discard object [mandatory]: + + void (*drop_object)(struct fscache_object *object) + + This method is called to indicate that an object has been unbound from its + cookie, and that the cache should release the object's resources and + retire it if it's in state FSCACHE_OBJECT_RECYCLING. + + This method should not attempt to release any references held by the + caller. The caller will invoke the put_object() method as appropriate. + + + (*) Release object reference [mandatory]: + + void (*put_object)(struct fscache_object *object) + + This method is used to discard a reference to an object. The object may + be freed when all the references to it are released. + + + (*) Synchronise a cache [mandatory]: + + void (*sync)(struct fscache_cache *cache) + + This is called to ask the backend to synchronise a cache with its backing + device. + + + (*) Dissociate a cache [mandatory]: + + void (*dissociate_pages)(struct fscache_cache *cache) + + This is called to ask a cache to perform any page dissociations as part of + cache withdrawal. + + + (*) Notification that the attributes on a netfs file changed [mandatory]: + + int (*attr_changed)(struct fscache_object *object); + + This is called to indicate to the cache that certain attributes on a netfs + file have changed (for example the maximum size a file may reach). The + cache can read these from the netfs by calling the cookie's get_attr() + method. + + The cache may use the file size information to reserve space on the cache. + It should also call fscache_set_store_limit() to indicate to FS-Cache the + highest byte it's willing to store for an object. + + This method may return -ve if an error occurred or the cache object cannot + be expanded. In such a case, the object will be withdrawn from service. + + This operation is run asynchronously from FS-Cache's thread pool, and + storage and retrieval operations from the netfs are excluded during the + execution of this operation. + + + (*) Reserve cache space for an object's data [optional]: + + int (*reserve_space)(struct fscache_object *object, loff_t size); + + This is called to request that cache space be reserved to hold the data + for an object and the metadata used to track it. Zero size should be + taken as request to cancel a reservation. + + This should return 0 if successful, -ENOSPC if there isn't enough space + available, or -ENOMEM or -EIO on other errors. + + The reservation may exceed the current size of the object, thus permitting + future expansion. If the amount of space consumed by an object would + exceed the reservation, it's permitted to refuse requests to allocate + pages, but not required. An object may be pruned down to its reservation + size if larger than that already. + + + (*) Request page be read from cache [mandatory]: + + int (*read_or_alloc_page)(struct fscache_retrieval *op, + struct page *page, + gfp_t gfp) + + This is called to attempt to read a netfs page from the cache, or to + reserve a backing block if not. FS-Cache will have done as much checking + as it can before calling, but most of the work belongs to the backend. + + If there's no page in the cache, then -ENODATA should be returned if the + backend managed to reserve a backing block; -ENOBUFS or -ENOMEM if it + didn't. + + If there is suitable data in the cache, then a read operation should be + queued and 0 returned. When the read finishes, fscache_end_io() should be + called. + + The fscache_mark_pages_cached() should be called for the page if any cache + metadata is retained. This will indicate to the netfs that the page needs + explicit uncaching. This operation takes a pagevec, thus allowing several + pages to be marked at once. + + The retrieval record pointed to by op should be retained for each page + queued and released when I/O on the page has been formally ended. + fscache_get/put_retrieval() are available for this purpose. + + The retrieval record may be used to get CPU time via the FS-Cache thread + pool. If this is desired, the op->op.processor should be set to point to + the appropriate processing routine, and fscache_enqueue_retrieval() should + be called at an appropriate point to request CPU time. For instance, the + retrieval routine could be enqueued upon the completion of a disk read. + The to_do field in the retrieval record is provided to aid in this. + + If an I/O error occurs, fscache_io_error() should be called and -ENOBUFS + returned if possible or fscache_end_io() called with a suitable error + code.. + + + (*) Request pages be read from cache [mandatory]: + + int (*read_or_alloc_pages)(struct fscache_retrieval *op, + struct list_head *pages, + unsigned *nr_pages, + gfp_t gfp) + + This is like the read_or_alloc_page() method, except it is handed a list + of pages instead of one page. Any pages on which a read operation is + started must be added to the page cache for the specified mapping and also + to the LRU. Such pages must also be removed from the pages list and + *nr_pages decremented per page. + + If there was an error such as -ENOMEM, then that should be returned; else + if one or more pages couldn't be read or allocated, then -ENOBUFS should + be returned; else if one or more pages couldn't be read, then -ENODATA + should be returned. If all the pages are dispatched then 0 should be + returned. + + + (*) Request page be allocated in the cache [mandatory]: + + int (*allocate_page)(struct fscache_retrieval *op, + struct page *page, + gfp_t gfp) + + This is like the read_or_alloc_page() method, except that it shouldn't + read from the cache, even if there's data there that could be retrieved. + It should, however, set up any internal metadata required such that + the write_page() method can write to the cache. + + If there's no backing block available, then -ENOBUFS should be returned + (or -ENOMEM if there were other problems). If a block is successfully + allocated, then the netfs page should be marked and 0 returned. + + + (*) Request pages be allocated in the cache [mandatory]: + + int (*allocate_pages)(struct fscache_retrieval *op, + struct list_head *pages, + unsigned *nr_pages, + gfp_t gfp) + + This is an multiple page version of the allocate_page() method. pages and + nr_pages should be treated as for the read_or_alloc_pages() method. + + + (*) Request page be written to cache [mandatory]: + + int (*write_page)(struct fscache_storage *op, + struct page *page); + + This is called to write from a page on which there was a previously + successful read_or_alloc_page() call or similar. FS-Cache filters out + pages that don't have mappings. + + This method is called asynchronously from the FS-Cache thread pool. It is + not required to actually store anything, provided -ENODATA is then + returned to the next read of this page. + + If an error occurred, then a negative error code should be returned, + otherwise zero should be returned. FS-Cache will take appropriate action + in response to an error, such as withdrawing this object. + + If this method returns success then FS-Cache will inform the netfs + appropriately. + + + (*) Discard retained per-page metadata [mandatory]: + + void (*uncache_page)(struct fscache_object *object, struct page *page) + + This is called when a netfs page is being evicted from the pagecache. The + cache backend should tear down any internal representation or tracking it + maintains for this page. + + +================== +FS-CACHE UTILITIES +================== + +FS-Cache provides some utilities that a cache backend may make use of: + + (*) Note occurrence of an I/O error in a cache: + + void fscache_io_error(struct fscache_cache *cache) + + This tells FS-Cache that an I/O error occurred in the cache. After this + has been called, only resource dissociation operations (object and page + release) will be passed from the netfs to the cache backend for the + specified cache. + + This does not actually withdraw the cache. That must be done separately. + + + (*) Invoke the retrieval I/O completion function: + + void fscache_end_io(struct fscache_retrieval *op, struct page *page, + int error); + + This is called to note the end of an attempt to retrieve a page. The + error value should be 0 if successful and an error otherwise. + + + (*) Set highest store limit: + + void fscache_set_store_limit(struct fscache_object *object, + loff_t i_size); + + This sets the limit FS-Cache imposes on the highest byte it's willing to + try and store for a netfs. Any page over this limit is automatically + rejected by fscache_read_alloc_page() and co with -ENOBUFS. + + + (*) Mark pages as being cached: + + void fscache_mark_pages_cached(struct fscache_retrieval *op, + struct pagevec *pagevec); + + This marks a set of pages as being cached. After this has been called, + the netfs must call fscache_uncache_page() to unmark the pages. + + + (*) Perform coherency check on an object: + + enum fscache_checkaux fscache_check_aux(struct fscache_object *object, + const void *data, + uint16_t datalen); + + This asks the netfs to perform a coherency check on an object that has + just been looked up. The cookie attached to the object will determine the + netfs to use. data and datalen should specify where the auxiliary data + retrieved from the cache can be found. + + One of three values will be returned: + + (*) FSCACHE_CHECKAUX_OKAY + + The coherency data indicates the object is valid as is. + + (*) FSCACHE_CHECKAUX_NEEDS_UPDATE + + The coherency data needs updating, but otherwise the object is + valid. + + (*) FSCACHE_CHECKAUX_OBSOLETE + + The coherency data indicates that the object is obsolete and should + be discarded. + + + (*) Initialise a freshly allocated object: + + void fscache_object_init(struct fscache_object *object); + + This initialises all the fields in an object representation. + + + (*) Indicate the destruction of an object: + + void fscache_object_destroyed(struct fscache_cache *cache); + + This must be called to inform FS-Cache that an object that belonged to a + cache has been destroyed and deallocated. This will allow continuation + of the cache withdrawal process when it is stopped pending destruction of + all the objects. + + + (*) Indicate negative lookup on an object: + + void fscache_object_lookup_negative(struct fscache_object *object); + + This is called to indicate to FS-Cache that a lookup process for an object + found a negative result. + + This changes the state of an object to permit reads pending on lookup + completion to go off and start fetching data from the netfs server as it's + known at this point that there can't be any data in the cache. + + This may be called multiple times on an object. Only the first call is + significant - all subsequent calls are ignored. + + + (*) Indicate an object has been obtained: + + void fscache_obtained_object(struct fscache_object *object); + + This is called to indicate to FS-Cache that a lookup process for an object + produced a positive result, or that an object was created. This should + only be called once for any particular object. + + This changes the state of an object to indicate: + + (1) if no call to fscache_object_lookup_negative() has been made on + this object, that there may be data available, and that reads can + now go and look for it; and + + (2) that writes may now proceed against this object. + + + (*) Indicate that object lookup failed: + + void fscache_object_lookup_error(struct fscache_object *object); + + This marks an object as having encountered a fatal error (usually EIO) + and causes it to move into a state whereby it will be withdrawn as soon + as possible. + + + (*) Get and release references on a retrieval record: + + void fscache_get_retrieval(struct fscache_retrieval *op); + void fscache_put_retrieval(struct fscache_retrieval *op); + + These two functions are used to retain a retrieval record whilst doing + asynchronous data retrieval and block allocation. + + + (*) Enqueue a retrieval record for processing. + + void fscache_enqueue_retrieval(struct fscache_retrieval *op); + + This enqueues a retrieval record for processing by the FS-Cache thread + pool. One of the threads in the pool will invoke the retrieval record's + op->op.processor callback function. This function may be called from + within the callback function. + + + (*) List of object state names: + + const char *fscache_object_states[]; + + For debugging purposes, this may be used to turn the state that an object + is in into a text string for display purposes. diff --git a/Documentation/filesystems/caching/cachefiles.txt b/Documentation/filesystems/caching/cachefiles.txt new file mode 100644 index 00000000000..c78a49b7bba --- /dev/null +++ b/Documentation/filesystems/caching/cachefiles.txt @@ -0,0 +1,501 @@ + =============================================== + CacheFiles: CACHE ON ALREADY MOUNTED FILESYSTEM + =============================================== + +Contents: + + (*) Overview. + + (*) Requirements. + + (*) Configuration. + + (*) Starting the cache. + + (*) Things to avoid. + + (*) Cache culling. + + (*) Cache structure. + + (*) Security model and SELinux. + + (*) A note on security. + + (*) Statistical information. + + (*) Debugging. + + +======== +OVERVIEW +======== + +CacheFiles is a caching backend that's meant to use as a cache a directory on +an already mounted filesystem of a local type (such as Ext3). + +CacheFiles uses a userspace daemon to do some of the cache management - such as +reaping stale nodes and culling. This is called cachefilesd and lives in +/sbin. + +The filesystem and data integrity of the cache are only as good as those of the +filesystem providing the backing services. Note that CacheFiles does not +attempt to journal anything since the journalling interfaces of the various +filesystems are very specific in nature. + +CacheFiles creates a misc character device - "/dev/cachefiles" - that is used +to communication with the daemon. Only one thing may have this open at once, +and whilst it is open, a cache is at least partially in existence. The daemon +opens this and sends commands down it to control the cache. + +CacheFiles is currently limited to a single cache. + +CacheFiles attempts to maintain at least a certain percentage of free space on +the filesystem, shrinking the cache by culling the objects it contains to make +space if necessary - see the "Cache Culling" section. This means it can be +placed on the same medium as a live set of data, and will expand to make use of +spare space and automatically contract when the set of data requires more +space. + + +============ +REQUIREMENTS +============ + +The use of CacheFiles and its daemon requires the following features to be +available in the system and in the cache filesystem: + + - dnotify. + + - extended attributes (xattrs). + + - openat() and friends. + + - bmap() support on files in the filesystem (FIBMAP ioctl). + + - The use of bmap() to detect a partial page at the end of the file. + +It is strongly recommended that the "dir_index" option is enabled on Ext3 +filesystems being used as a cache. + + +============= +CONFIGURATION +============= + +The cache is configured by a script in /etc/cachefilesd.conf. These commands +set up cache ready for use. The following script commands are available: + + (*) brun <N>% + (*) bcull <N>% + (*) bstop <N>% + (*) frun <N>% + (*) fcull <N>% + (*) fstop <N>% + + Configure the culling limits. Optional. See the section on culling + The defaults are 7% (run), 5% (cull) and 1% (stop) respectively. + + The commands beginning with a 'b' are file space (block) limits, those + beginning with an 'f' are file count limits. + + (*) dir <path> + + Specify the directory containing the root of the cache. Mandatory. + + (*) tag <name> + + Specify a tag to FS-Cache to use in distinguishing multiple caches. + Optional. The default is "CacheFiles". + + (*) debug <mask> + + Specify a numeric bitmask to control debugging in the kernel module. + Optional. The default is zero (all off). The following values can be + OR'd into the mask to collect various information: + + 1 Turn on trace of function entry (_enter() macros) + 2 Turn on trace of function exit (_leave() macros) + 4 Turn on trace of internal debug points (_debug()) + + This mask can also be set through sysfs, eg: + + echo 5 >/sys/modules/cachefiles/parameters/debug + + +================== +STARTING THE CACHE +================== + +The cache is started by running the daemon. The daemon opens the cache device, +configures the cache and tells it to begin caching. At that point the cache +binds to fscache and the cache becomes live. + +The daemon is run as follows: + + /sbin/cachefilesd [-d]* [-s] [-n] [-f <configfile>] + +The flags are: + + (*) -d + + Increase the debugging level. This can be specified multiple times and + is cumulative with itself. + + (*) -s + + Send messages to stderr instead of syslog. + + (*) -n + + Don't daemonise and go into background. + + (*) -f <configfile> + + Use an alternative configuration file rather than the default one. + + +=============== +THINGS TO AVOID +=============== + +Do not mount other things within the cache as this will cause problems. The +kernel module contains its own very cut-down path walking facility that ignores +mountpoints, but the daemon can't avoid them. + +Do not create, rename or unlink files and directories in the cache whilst the +cache is active, as this may cause the state to become uncertain. + +Renaming files in the cache might make objects appear to be other objects (the +filename is part of the lookup key). + +Do not change or remove the extended attributes attached to cache files by the +cache as this will cause the cache state management to get confused. + +Do not create files or directories in the cache, lest the cache get confused or +serve incorrect data. + +Do not chmod files in the cache. The module creates things with minimal +permissions to prevent random users being able to access them directly. + + +============= +CACHE CULLING +============= + +The cache may need culling occasionally to make space. This involves +discarding objects from the cache that have been used less recently than +anything else. Culling is based on the access time of data objects. Empty +directories are culled if not in use. + +Cache culling is done on the basis of the percentage of blocks and the +percentage of files available in the underlying filesystem. There are six +"limits": + + (*) brun + (*) frun + + If the amount of free space and the number of available files in the cache + rises above both these limits, then culling is turned off. + + (*) bcull + (*) fcull + + If the amount of available space or the number of available files in the + cache falls below either of these limits, then culling is started. + + (*) bstop + (*) fstop + + If the amount of available space or the number of available files in the + cache falls below either of these limits, then no further allocation of + disk space or files is permitted until culling has raised things above + these limits again. + +These must be configured thusly: + + 0 <= bstop < bcull < brun < 100 + 0 <= fstop < fcull < frun < 100 + +Note that these are percentages of available space and available files, and do +_not_ appear as 100 minus the percentage displayed by the "df" program. + +The userspace daemon scans the cache to build up a table of cullable objects. +These are then culled in least recently used order. A new scan of the cache is +started as soon as space is made in the table. Objects will be skipped if +their atimes have changed or if the kernel module says it is still using them. + + +=============== +CACHE STRUCTURE +=============== + +The CacheFiles module will create two directories in the directory it was +given: + + (*) cache/ + + (*) graveyard/ + +The active cache objects all reside in the first directory. The CacheFiles +kernel module moves any retired or culled objects that it can't simply unlink +to the graveyard from which the daemon will actually delete them. + +The daemon uses dnotify to monitor the graveyard directory, and will delete +anything that appears therein. + + +The module represents index objects as directories with the filename "I..." or +"J...". Note that the "cache/" directory is itself a special index. + +Data objects are represented as files if they have no children, or directories +if they do. Their filenames all begin "D..." or "E...". If represented as a +directory, data objects will have a file in the directory called "data" that +actually holds the data. + +Special objects are similar to data objects, except their filenames begin +"S..." or "T...". + + +If an object has children, then it will be represented as a directory. +Immediately in the representative directory are a collection of directories +named for hash values of the child object keys with an '@' prepended. Into +this directory, if possible, will be placed the representations of the child +objects: + + INDEX INDEX INDEX DATA FILES + ========= ========== ================================= ================ + cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400 + cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...DB1ry + cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...N22ry + cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...FP1ry + + +If the key is so long that it exceeds NAME_MAX with the decorations added on to +it, then it will be cut into pieces, the first few of which will be used to +make a nest of directories, and the last one of which will be the objects +inside the last directory. The names of the intermediate directories will have +'+' prepended: + + J1223/@23/+xy...z/+kl...m/Epqr + + +Note that keys are raw data, and not only may they exceed NAME_MAX in size, +they may also contain things like '/' and NUL characters, and so they may not +be suitable for turning directly into a filename. + +To handle this, CacheFiles will use a suitably printable filename directly and +"base-64" encode ones that aren't directly suitable. The two versions of +object filenames indicate the encoding: + + OBJECT TYPE PRINTABLE ENCODED + =============== =============== =============== + Index "I..." "J..." + Data "D..." "E..." + Special "S..." "T..." + +Intermediate directories are always "@" or "+" as appropriate. + + +Each object in the cache has an extended attribute label that holds the object +type ID (required to distinguish special objects) and the auxiliary data from +the netfs. The latter is used to detect stale objects in the cache and update +or retire them. + + +Note that CacheFiles will erase from the cache any file it doesn't recognise or +any file of an incorrect type (such as a FIFO file or a device file). + + +========================== +SECURITY MODEL AND SELINUX +========================== + +CacheFiles is implemented to deal properly with the LSM security features of +the Linux kernel and the SELinux facility. + +One of the problems that CacheFiles faces is that it is generally acting on +behalf of a process, and running in that process's context, and that includes a +security context that is not appropriate for accessing the cache - either +because the files in the cache are inaccessible to that process, or because if +the process creates a file in the cache, that file may be inaccessible to other +processes. + +The way CacheFiles works is to temporarily change the security context (fsuid, +fsgid and actor security label) that the process acts as - without changing the +security context of the process when it the target of an operation performed by +some other process (so signalling and suchlike still work correctly). + + +When the CacheFiles module is asked to bind to its cache, it: + + (1) Finds the security label attached to the root cache directory and uses + that as the security label with which it will create files. By default, + this is: + + cachefiles_var_t + + (2) Finds the security label of the process which issued the bind request + (presumed to be the cachefilesd daemon), which by default will be: + + cachefilesd_t + + and asks LSM to supply a security ID as which it should act given the + daemon's label. By default, this will be: + + cachefiles_kernel_t + + SELinux transitions the daemon's security ID to the module's security ID + based on a rule of this form in the policy. + + type_transition <daemon's-ID> kernel_t : process <module's-ID>; + + For instance: + + type_transition cachefilesd_t kernel_t : process cachefiles_kernel_t; + + +The module's security ID gives it permission to create, move and remove files +and directories in the cache, to find and access directories and files in the +cache, to set and access extended attributes on cache objects, and to read and +write files in the cache. + +The daemon's security ID gives it only a very restricted set of permissions: it +may scan directories, stat files and erase files and directories. It may +not read or write files in the cache, and so it is precluded from accessing the +data cached therein; nor is it permitted to create new files in the cache. + + +There are policy source files available in: + + http://people.redhat.com/~dhowells/fscache/cachefilesd-0.8.tar.bz2 + +and later versions. In that tarball, see the files: + + cachefilesd.te + cachefilesd.fc + cachefilesd.if + +They are built and installed directly by the RPM. + +If a non-RPM based system is being used, then copy the above files to their own +directory and run: + + make -f /usr/share/selinux/devel/Makefile + semodule -i cachefilesd.pp + +You will need checkpolicy and selinux-policy-devel installed prior to the +build. + + +By default, the cache is located in /var/fscache, but if it is desirable that +it should be elsewhere, than either the above policy files must be altered, or +an auxiliary policy must be installed to label the alternate location of the +cache. + +For instructions on how to add an auxiliary policy to enable the cache to be +located elsewhere when SELinux is in enforcing mode, please see: + + /usr/share/doc/cachefilesd-*/move-cache.txt + +When the cachefilesd rpm is installed; alternatively, the document can be found +in the sources. + + +================== +A NOTE ON SECURITY +================== + +CacheFiles makes use of the split security in the task_struct. It allocates +its own task_security structure, and redirects current->act_as to point to it +when it acts on behalf of another process, in that process's context. + +The reason it does this is that it calls vfs_mkdir() and suchlike rather than +bypassing security and calling inode ops directly. Therefore the VFS and LSM +may deny the CacheFiles access to the cache data because under some +circumstances the caching code is running in the security context of whatever +process issued the original syscall on the netfs. + +Furthermore, should CacheFiles create a file or directory, the security +parameters with that object is created (UID, GID, security label) would be +derived from that process that issued the system call, thus potentially +preventing other processes from accessing the cache - including CacheFiles's +cache management daemon (cachefilesd). + +What is required is to temporarily override the security of the process that +issued the system call. We can't, however, just do an in-place change of the +security data as that affects the process as an object, not just as a subject. +This means it may lose signals or ptrace events for example, and affects what +the process looks like in /proc. + +So CacheFiles makes use of a logical split in the security between the +objective security (task->sec) and the subjective security (task->act_as). The +objective security holds the intrinsic security properties of a process and is +never overridden. This is what appears in /proc, and is what is used when a +process is the target of an operation by some other process (SIGKILL for +example). + +The subjective security holds the active security properties of a process, and +may be overridden. This is not seen externally, and is used whan a process +acts upon another object, for example SIGKILLing another process or opening a +file. + +LSM hooks exist that allow SELinux (or Smack or whatever) to reject a request +for CacheFiles to run in a context of a specific security label, or to create +files and directories with another security label. + + +======================= +STATISTICAL INFORMATION +======================= + +If FS-Cache is compiled with the following option enabled: + + CONFIG_CACHEFILES_HISTOGRAM=y + +then it will gather certain statistics and display them through a proc file. + + (*) /proc/fs/cachefiles/histogram + + cat /proc/fs/cachefiles/histogram + JIFS SECS LOOKUPS MKDIRS CREATES + ===== ===== ========= ========= ========= + + This shows the breakdown of the number of times each amount of time + between 0 jiffies and HZ-1 jiffies a variety of tasks took to run. The + columns are as follows: + + COLUMN TIME MEASUREMENT + ======= ======================================================= + LOOKUPS Length of time to perform a lookup on the backing fs + MKDIRS Length of time to perform a mkdir on the backing fs + CREATES Length of time to perform a create on the backing fs + + Each row shows the number of events that took a particular range of times. + Each step is 1 jiffy in size. The JIFS column indicates the particular + jiffy range covered, and the SECS field the equivalent number of seconds. + + +========= +DEBUGGING +========= + +If CONFIG_CACHEFILES_DEBUG is enabled, the CacheFiles facility can have runtime +debugging enabled by adjusting the value in: + + /sys/module/cachefiles/parameters/debug + +This is a bitmask of debugging streams to enable: + + BIT VALUE STREAM POINT + ======= ======= =============================== ======================= + 0 1 General Function entry trace + 1 2 Function exit trace + 2 4 General + +The appropriate set of values should be OR'd together and the result written to +the control file. For example: + + echo $((1|4|8)) >/sys/module/cachefiles/parameters/debug + +will turn on all function entry debugging. diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt new file mode 100644 index 00000000000..9e94b9491d8 --- /dev/null +++ b/Documentation/filesystems/caching/fscache.txt @@ -0,0 +1,333 @@ + ========================== + General Filesystem Caching + ========================== + +======== +OVERVIEW +======== + +This facility is a general purpose cache for network filesystems, though it +could be used for caching other things such as ISO9660 filesystems too. + +FS-Cache mediates between cache backends (such as CacheFS) and network +filesystems: + + +---------+ + | | +--------------+ + | NFS |--+ | | + | | | +-->| CacheFS | + +---------+ | +----------+ | | /dev/hda5 | + | | | | +--------------+ + +---------+ +-->| | | + | | | |--+ + | AFS |----->| FS-Cache | + | | | |--+ + +---------+ +-->| | | + | | | | +--------------+ + +---------+ | +----------+ | | | + | | | +-->| CacheFiles | + | ISOFS |--+ | /var/cache | + | | +--------------+ + +---------+ + +Or to look at it another way, FS-Cache is a module that provides a caching +facility to a network filesystem such that the cache is transparent to the +user: + + +---------+ + | | + | Server | + | | + +---------+ + | NETWORK + ~~~~~|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + | + | +----------+ + V | | + +---------+ | | + | | | | + | NFS |----->| FS-Cache | + | | | |--+ + +---------+ | | | +--------------+ +--------------+ + | | | | | | | | + V +----------+ +-->| CacheFiles |-->| Ext3 | + +---------+ | /var/cache | | /dev/sda6 | + | | +--------------+ +--------------+ + | VFS | ^ ^ + | | | | + +---------+ +--------------+ | + | KERNEL SPACE | | + ~~~~~|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|~~~~~~|~~~~ + | USER SPACE | | + V | | + +---------+ +--------------+ + | | | | + | Process | | cachefilesd | + | | | | + +---------+ +--------------+ + + +FS-Cache does not follow the idea of completely loading every netfs file +opened in its entirety into a cache before permitting it to be accessed and +then serving the pages out of that cache rather than the netfs inode because: + + (1) It must be practical to operate without a cache. + + (2) The size of any accessible file must not be limited to the size of the + cache. + + (3) The combined size of all opened files (this includes mapped libraries) + must not be limited to the size of the cache. + + (4) The user should not be forced to download an entire file just to do a + one-off access of a small portion of it (such as might be done with the + "file" program). + +It instead serves the cache out in PAGE_SIZE chunks as and when requested by +the netfs('s) using it. + + +FS-Cache provides the following facilities: + + (1) More than one cache can be used at once. Caches can be selected + explicitly by use of tags. + + (2) Caches can be added / removed at any time. + + (3) The netfs is provided with an interface that allows either party to + withdraw caching facilities from a file (required for (2)). + + (4) The interface to the netfs returns as few errors as possible, preferring + rather to let the netfs remain oblivious. + + (5) Cookies are used to represent indices, files and other objects to the + netfs. The simplest cookie is just a NULL pointer - indicating nothing + cached there. + + (6) The netfs is allowed to propose - dynamically - any index hierarchy it + desires, though it must be aware that the index search function is + recursive, stack space is limited, and indices can only be children of + indices. + + (7) Data I/O is done direct to and from the netfs's pages. The netfs + indicates that page A is at index B of the data-file represented by cookie + C, and that it should be read or written. The cache backend may or may + not start I/O on that page, but if it does, a netfs callback will be + invoked to indicate completion. The I/O may be either synchronous or + asynchronous. + + (8) Cookies can be "retired" upon release. At this point FS-Cache will mark + them as obsolete and the index hierarchy rooted at that point will get + recycled. + + (9) The netfs provides a "match" function for index searches. In addition to + saying whether a match was made or not, this can also specify that an + entry should be updated or deleted. + +(10) As much as possible is done asynchronously. + + +FS-Cache maintains a virtual indexing tree in which all indices, files, objects +and pages are kept. Bits of this tree may actually reside in one or more +caches. + + FSDEF + | + +------------------------------------+ + | | + NFS AFS + | | + +--------------------------+ +-----------+ + | | | | + homedir mirror afs.org redhat.com + | | | + +------------+ +---------------+ +----------+ + | | | | | | + 00001 00002 00007 00125 vol00001 vol00002 + | | | | | + +---+---+ +-----+ +---+ +------+------+ +-----+----+ + | | | | | | | | | | | | | +PG0 PG1 PG2 PG0 XATTR PG0 PG1 DIRENT DIRENT DIRENT R/W R/O Bak + | | + PG0 +-------+ + | | + 00001 00003 + | + +---+---+ + | | | + PG0 PG1 PG2 + +In the example above, you can see two netfs's being backed: NFS and AFS. These +have different index hierarchies: + + (*) The NFS primary index contains per-server indices. Each server index is + indexed by NFS file handles to get data file objects. Each data file + objects can have an array of pages, but may also have further child + objects, such as extended attributes and directory entries. Extended + attribute objects themselves have page-array contents. + + (*) The AFS primary index contains per-cell indices. Each cell index contains + per-logical-volume indices. Each of volume index contains up to three + indices for the read-write, read-only and backup mirrors of those volumes. + Each of these contains vnode data file objects, each of which contains an + array of pages. + +The very top index is the FS-Cache master index in which individual netfs's +have entries. + +Any index object may reside in more than one cache, provided it only has index +children. Any index with non-index object children will be assumed to only +reside in one cache. + + +The netfs API to FS-Cache can be found in: + + Documentation/filesystems/caching/netfs-api.txt + +The cache backend API to FS-Cache can be found in: + + Documentation/filesystems/caching/backend-api.txt + +A description of the internal representations and object state machine can be +found in: + + Documentation/filesystems/caching/object.txt + + +======================= +STATISTICAL INFORMATION +======================= + +If FS-Cache is compiled with the following options enabled: + + CONFIG_FSCACHE_STATS=y + CONFIG_FSCACHE_HISTOGRAM=y + +then it will gather certain statistics and display them through a number of +proc files. + + (*) /proc/fs/fscache/stats + + This shows counts of a number of events that can happen in FS-Cache: + + CLASS EVENT MEANING + ======= ======= ======================================================= + Cookies idx=N Number of index cookies allocated + dat=N Number of data storage cookies allocated + spc=N Number of special cookies allocated + Objects alc=N Number of objects allocated + nal=N Number of object allocation failures + avl=N Number of objects that reached the available state + ded=N Number of objects that reached the dead state + ChkAux non=N Number of objects that didn't have a coherency check + ok=N Number of objects that passed a coherency check + upd=N Number of objects that needed a coherency data update + obs=N Number of objects that were declared obsolete + Pages mrk=N Number of pages marked as being cached + unc=N Number of uncache page requests seen + Acquire n=N Number of acquire cookie requests seen + nul=N Number of acq reqs given a NULL parent + noc=N Number of acq reqs rejected due to no cache available + ok=N Number of acq reqs succeeded + nbf=N Number of acq reqs rejected due to error + oom=N Number of acq reqs failed on ENOMEM + Lookups n=N Number of lookup calls made on cache backends + neg=N Number of negative lookups made + pos=N Number of positive lookups made + crt=N Number of objects created by lookup + Updates n=N Number of update cookie requests seen + nul=N Number of upd reqs given a NULL parent + run=N Number of upd reqs granted CPU time + Relinqs n=N Number of relinquish cookie requests seen + nul=N Number of rlq reqs given a NULL parent + wcr=N Number of rlq reqs waited on completion of creation + AttrChg n=N Number of attribute changed requests seen + ok=N Number of attr changed requests queued + nbf=N Number of attr changed rejected -ENOBUFS + oom=N Number of attr changed failed -ENOMEM + run=N Number of attr changed ops given CPU time + Allocs n=N Number of allocation requests seen + ok=N Number of successful alloc reqs + wt=N Number of alloc reqs that waited on lookup completion + nbf=N Number of alloc reqs rejected -ENOBUFS + ops=N Number of alloc reqs submitted + owt=N Number of alloc reqs waited for CPU time + Retrvls n=N Number of retrieval (read) requests seen + ok=N Number of successful retr reqs + wt=N Number of retr reqs that waited on lookup completion + nod=N Number of retr reqs returned -ENODATA + nbf=N Number of retr reqs rejected -ENOBUFS + int=N Number of retr reqs aborted -ERESTARTSYS + oom=N Number of retr reqs failed -ENOMEM + ops=N Number of retr reqs submitted + owt=N Number of retr reqs waited for CPU time + Stores n=N Number of storage (write) requests seen + ok=N Number of successful store reqs + agn=N Number of store reqs on a page already pending storage + nbf=N Number of store reqs rejected -ENOBUFS + oom=N Number of store reqs failed -ENOMEM + ops=N Number of store reqs submitted + run=N Number of store reqs granted CPU time + Ops pend=N Number of times async ops added to pending queues + run=N Number of times async ops given CPU time + enq=N Number of times async ops queued for processing + dfr=N Number of async ops queued for deferred release + rel=N Number of async ops released + gc=N Number of deferred-release async ops garbage collected + + + (*) /proc/fs/fscache/histogram + + cat /proc/fs/fscache/histogram + JIFS SECS OBJ INST OP RUNS OBJ RUNS RETRV DLY RETRIEVLS + ===== ===== ========= ========= ========= ========= ========= + + This shows the breakdown of the number of times each amount of time + between 0 jiffies and HZ-1 jiffies a variety of tasks took to run. The + columns are as follows: + + COLUMN TIME MEASUREMENT + ======= ======================================================= + OBJ INST Length of time to instantiate an object + OP RUNS Length of time a call to process an operation took + OBJ RUNS Length of time a call to process an object event took + RETRV DLY Time between an requesting a read and lookup completing + RETRIEVLS Time between beginning and end of a retrieval + + Each row shows the number of events that took a particular range of times. + Each step is 1 jiffy in size. The JIFS column indicates the particular + jiffy range covered, and the SECS field the equivalent number of seconds. + + +========= +DEBUGGING +========= + +If CONFIG_FSCACHE_DEBUG is enabled, the FS-Cache facility can have runtime +debugging enabled by adjusting the value in: + + /sys/module/fscache/parameters/debug + +This is a bitmask of debugging streams to enable: + + BIT VALUE STREAM POINT + ======= ======= =============================== ======================= + 0 1 Cache management Function entry trace + 1 2 Function exit trace + 2 4 General + 3 8 Cookie management Function entry trace + 4 16 Function exit trace + 5 32 General + 6 64 Page handling Function entry trace + 7 128 Function exit trace + 8 256 General + 9 512 Operation management Function entry trace + 10 1024 Function exit trace + 11 2048 General + +The appropriate set of values should be OR'd together and the result written to +the control file. For example: + + echo $((1|8|64)) >/sys/module/fscache/parameters/debug + +will turn on all function entry debugging. diff --git a/Documentation/filesystems/caching/netfs-api.txt b/Documentation/filesystems/caching/netfs-api.txt new file mode 100644 index 00000000000..4db125b3a5c --- /dev/null +++ b/Documentation/filesystems/caching/netfs-api.txt @@ -0,0 +1,778 @@ + =============================== + FS-CACHE NETWORK FILESYSTEM API + =============================== + +There's an API by which a network filesystem can make use of the FS-Cache +facilities. This is based around a number of principles: + + (1) Caches can store a number of different object types. There are two main + object types: indices and files. The first is a special type used by + FS-Cache to make finding objects faster and to make retiring of groups of + objects easier. + + (2) Every index, file or other object is represented by a cookie. This cookie + may or may not have anything associated with it, but the netfs doesn't + need to care. + + (3) Barring the top-level index (one entry per cached netfs), the index + hierarchy for each netfs is structured according the whim of the netfs. + +This API is declared in <linux/fscache.h>. + +This document contains the following sections: + + (1) Network filesystem definition + (2) Index definition + (3) Object definition + (4) Network filesystem (un)registration + (5) Cache tag lookup + (6) Index registration + (7) Data file registration + (8) Miscellaneous object registration + (9) Setting the data file size + (10) Page alloc/read/write + (11) Page uncaching + (12) Index and data file update + (13) Miscellaneous cookie operations + (14) Cookie unregistration + (15) Index and data file invalidation + (16) FS-Cache specific page flags. + + +============================= +NETWORK FILESYSTEM DEFINITION +============================= + +FS-Cache needs a description of the network filesystem. This is specified +using a record of the following structure: + + struct fscache_netfs { + uint32_t version; + const char *name; + struct fscache_cookie *primary_index; + ... + }; + +This first two fields should be filled in before registration, and the third +will be filled in by the registration function; any other fields should just be +ignored and are for internal use only. + +The fields are: + + (1) The name of the netfs (used as the key in the toplevel index). + + (2) The version of the netfs (if the name matches but the version doesn't, the + entire in-cache hierarchy for this netfs will be scrapped and begun + afresh). + + (3) The cookie representing the primary index will be allocated according to + another parameter passed into the registration function. + +For example, kAFS (linux/fs/afs/) uses the following definitions to describe +itself: + + struct fscache_netfs afs_cache_netfs = { + .version = 0, + .name = "afs", + }; + + +================ +INDEX DEFINITION +================ + +Indices are used for two purposes: + + (1) To aid the finding of a file based on a series of keys (such as AFS's + "cell", "volume ID", "vnode ID"). + + (2) To make it easier to discard a subset of all the files cached based around + a particular key - for instance to mirror the removal of an AFS volume. + +However, since it's unlikely that any two netfs's are going to want to define +their index hierarchies in quite the same way, FS-Cache tries to impose as few +restraints as possible on how an index is structured and where it is placed in +the tree. The netfs can even mix indices and data files at the same level, but +it's not recommended. + +Each index entry consists of a key of indeterminate length plus some auxilliary +data, also of indeterminate length. + +There are some limits on indices: + + (1) Any index containing non-index objects should be restricted to a single + cache. Any such objects created within an index will be created in the + first cache only. The cache in which an index is created can be + controlled by cache tags (see below). + + (2) The entry data must be atomically journallable, so it is limited to about + 400 bytes at present. At least 400 bytes will be available. + + (3) The depth of the index tree should be judged with care as the search + function is recursive. Too many layers will run the kernel out of stack. + + +================= +OBJECT DEFINITION +================= + +To define an object, a structure of the following type should be filled out: + + struct fscache_cookie_def + { + uint8_t name[16]; + uint8_t type; + + struct fscache_cache_tag *(*select_cache)( + const void *parent_netfs_data, + const void *cookie_netfs_data); + + uint16_t (*get_key)(const void *cookie_netfs_data, + void *buffer, + uint16_t bufmax); + + void (*get_attr)(const void *cookie_netfs_data, + uint64_t *size); + + uint16_t (*get_aux)(const void *cookie_netfs_data, + void *buffer, + uint16_t bufmax); + + enum fscache_checkaux (*check_aux)(void *cookie_netfs_data, + const void *data, + uint16_t datalen); + + void (*get_context)(void *cookie_netfs_data, void *context); + + void (*put_context)(void *cookie_netfs_data, void *context); + + void (*mark_pages_cached)(void *cookie_netfs_data, + struct address_space *mapping, + struct pagevec *cached_pvec); + + void (*now_uncached)(void *cookie_netfs_data); + }; + +This has the following fields: + + (1) The type of the object [mandatory]. + + This is one of the following values: + + (*) FSCACHE_COOKIE_TYPE_INDEX + + This defines an index, which is a special FS-Cache type. + + (*) FSCACHE_COOKIE_TYPE_DATAFILE + + This defines an ordinary data file. + + (*) Any other value between 2 and 255 + + This defines an extraordinary object such as an XATTR. + + (2) The name of the object type (NUL terminated unless all 16 chars are used) + [optional]. + + (3) A function to select the cache in which to store an index [optional]. + + This function is invoked when an index needs to be instantiated in a cache + during the instantiation of a non-index object. Only the immediate index + parent for the non-index object will be queried. Any indices above that + in the hierarchy may be stored in multiple caches. This function does not + need to be supplied for any non-index object or any index that will only + have index children. + + If this function is not supplied or if it returns NULL then the first + cache in the parent's list will be chosed, or failing that, the first + cache in the master list. + + (4) A function to retrieve an object's key from the netfs [mandatory]. + + This function will be called with the netfs data that was passed to the + cookie acquisition function and the maximum length of key data that it may + provide. It should write the required key data into the given buffer and + return the quantity it wrote. + + (5) A function to retrieve attribute data from the netfs [optional]. + + This function will be called with the netfs data that was passed to the + cookie acquisition function. It should return the size of the file if + this is a data file. The size may be used to govern how much cache must + be reserved for this file in the cache. + + If the function is absent, a file size of 0 is assumed. + + (6) A function to retrieve auxilliary data from the netfs [optional]. + + This function will be called with the netfs data that was passed to the + cookie acquisition function and the maximum length of auxilliary data that + it may provide. It should write the auxilliary data into the given buffer + and return the quantity it wrote. + + If this function is absent, the auxilliary data length will be set to 0. + + The length of the auxilliary data buffer may be dependent on the key + length. A netfs mustn't rely on being able to provide more than 400 bytes + for both. + + (7) A function to check the auxilliary data [optional]. + + This function will be called to check that a match found in the cache for + this object is valid. For instance with AFS it could check the auxilliary + data against the data version number returned by the server to determine + whether the index entry in a cache is still valid. + + If this function is absent, it will be assumed that matching objects in a + cache are always valid. + + If present, the function should return one of the following values: + + (*) FSCACHE_CHECKAUX_OKAY - the entry is okay as is + (*) FSCACHE_CHECKAUX_NEEDS_UPDATE - the entry requires update + (*) FSCACHE_CHECKAUX_OBSOLETE - the entry should be deleted + + This function can also be used to extract data from the auxilliary data in + the cache and copy it into the netfs's structures. + + (8) A pair of functions to manage contexts for the completion callback + [optional]. + + The cache read/write functions are passed a context which is then passed + to the I/O completion callback function. To ensure this context remains + valid until after the I/O completion is called, two functions may be + provided: one to get an extra reference on the context, and one to drop a + reference to it. + + If the context is not used or is a type of object that won't go out of + scope, then these functions are not required. These functions are not + required for indices as indices may not contain data. These functions may + be called in interrupt context and so may not sleep. + + (9) A function to mark a page as retaining cache metadata [optional]. + + This is called by the cache to indicate that it is retaining in-memory + information for this page and that the netfs should uncache the page when + it has finished. This does not indicate whether there's data on the disk + or not. Note that several pages at once may be presented for marking. + + The PG_fscache bit is set on the pages before this function would be + called, so the function need not be provided if this is sufficient. + + This function is not required for indices as they're not permitted data. + +(10) A function to unmark all the pages retaining cache metadata [mandatory]. + + This is called by FS-Cache to indicate that a backing store is being + unbound from a cookie and that all the marks on the pages should be + cleared to prevent confusion. Note that the cache will have torn down all + its tracking information so that the pages don't need to be explicitly + uncached. + + This function is not required for indices as they're not permitted data. + + +=================================== +NETWORK FILESYSTEM (UN)REGISTRATION +=================================== + +The first step is to declare the network filesystem to the cache. This also +involves specifying the layout of the primary index (for AFS, this would be the +"cell" level). + +The registration function is: + + int fscache_register_netfs(struct fscache_netfs *netfs); + +It just takes a pointer to the netfs definition. It returns 0 or an error as +appropriate. + +For kAFS, registration is done as follows: + + ret = fscache_register_netfs(&afs_cache_netfs); + +The last step is, of course, unregistration: + + void fscache_unregister_netfs(struct fscache_netfs *netfs); + + +================ +CACHE TAG LOOKUP +================ + +FS-Cache permits the use of more than one cache. To permit particular index +subtrees to be bound to particular caches, the second step is to look up cache +representation tags. This step is optional; it can be left entirely up to +FS-Cache as to which cache should be used. The problem with doing that is that +FS-Cache will always pick the first cache that was registered. + +To get the representation for a named tag: + + struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name); + +This takes a text string as the name and returns a representation of a tag. It +will never return an error. It may return a dummy tag, however, if it runs out +of memory; this will inhibit caching with this tag. + +Any representation so obtained must be released by passing it to this function: + + void fscache_release_cache_tag(struct fscache_cache_tag *tag); + +The tag will be retrieved by FS-Cache when it calls the object definition +operation select_cache(). + + +================== +INDEX REGISTRATION +================== + +The third step is to inform FS-Cache about part of an index hierarchy that can +be used to locate files. This is done by requesting a cookie for each index in +the path to the file: + + struct fscache_cookie * + fscache_acquire_cookie(struct fscache_cookie *parent, + const struct fscache_object_def *def, + void *netfs_data); + +This function creates an index entry in the index represented by parent, +filling in the index entry by calling the operations pointed to by def. + +Note that this function never returns an error - all errors are handled +internally. It may, however, return NULL to indicate no cookie. It is quite +acceptable to pass this token back to this function as the parent to another +acquisition (or even to the relinquish cookie, read page and write page +functions - see below). + +Note also that no indices are actually created in a cache until a non-index +object needs to be created somewhere down the hierarchy. Furthermore, an index +may be created in several different caches independently at different times. +This is all handled transparently, and the netfs doesn't see any of it. + +For example, with AFS, a cell would be added to the primary index. This index +entry would have a dependent inode containing a volume location index for the +volume mappings within this cell: + + cell->cache = + fscache_acquire_cookie(afs_cache_netfs.primary_index, + &afs_cell_cache_index_def, + cell); + +Then when a volume location was accessed, it would be entered into the cell's +index and an inode would be allocated that acts as a volume type and hash chain +combination: + + vlocation->cache = + fscache_acquire_cookie(cell->cache, + &afs_vlocation_cache_index_def, + vlocation); + +And then a particular flavour of volume (R/O for example) could be added to +that index, creating another index for vnodes (AFS inode equivalents): + + volume->cache = + fscache_acquire_cookie(vlocation->cache, + &afs_volume_cache_index_def, + volume); + + +====================== +DATA FILE REGISTRATION +====================== + +The fourth step is to request a data file be created in the cache. This is +identical to index cookie acquisition. The only difference is that the type in +the object definition should be something other than index type. + + vnode->cache = + fscache_acquire_cookie(volume->cache, + &afs_vnode_cache_object_def, + vnode); + + +================================= +MISCELLANEOUS OBJECT REGISTRATION +================================= + +An optional step is to request an object of miscellaneous type be created in +the cache. This is almost identical to index cookie acquisition. The only +difference is that the type in the object definition should be something other +than index type. Whilst the parent object could be an index, it's more likely +it would be some other type of object such as a data file. + + xattr->cache = + fscache_acquire_cookie(vnode->cache, + &afs_xattr_cache_object_def, + xattr); + +Miscellaneous objects might be used to store extended attributes or directory +entries for example. + + +========================== +SETTING THE DATA FILE SIZE +========================== + +The fifth step is to set the physical attributes of the file, such as its size. +This doesn't automatically reserve any space in the cache, but permits the +cache to adjust its metadata for data tracking appropriately: + + int fscache_attr_changed(struct fscache_cookie *cookie); + +The cache will return -ENOBUFS if there is no backing cache or if there is no +space to allocate any extra metadata required in the cache. The attributes +will be accessed with the get_attr() cookie definition operation. + +Note that attempts to read or write data pages in the cache over this size may +be rebuffed with -ENOBUFS. + +This operation schedules an attribute adjustment to happen asynchronously at +some point in the future, and as such, it may happen after the function returns +to the caller. The attribute adjustment excludes read and write operations. + + +===================== +PAGE READ/ALLOC/WRITE +===================== + +And the sixth step is to store and retrieve pages in the cache. There are +three functions that are used to do this. + +Note: + + (1) A page should not be re-read or re-allocated without uncaching it first. + + (2) A read or allocated page must be uncached when the netfs page is released + from the pagecache. + + (3) A page should only be written to the cache if previous read or allocated. + +This permits the cache to maintain its page tracking in proper order. + + +PAGE READ +--------- + +Firstly, the netfs should ask FS-Cache to examine the caches and read the +contents cached for a particular page of a particular file if present, or else +allocate space to store the contents if not: + + typedef + void (*fscache_rw_complete_t)(struct page *page, + void *context, + int error); + + int fscache_read_or_alloc_page(struct fscache_cookie *cookie, + struct page *page, + fscache_rw_complete_t end_io_func, + void *context, + gfp_t gfp); + +The cookie argument must specify a cookie for an object that isn't an index, +the page specified will have the data loaded into it (and is also used to +specify the page number), and the gfp argument is used to control how any +memory allocations made are satisfied. + +If the cookie indicates the inode is not cached: + + (1) The function will return -ENOBUFS. + +Else if there's a copy of the page resident in the cache: + + (1) The mark_pages_cached() cookie operation will be called on that page. + + (2) The function will submit a request to read the data from the cache's + backing device directly into the page specified. + + (3) The function will return 0. + + (4) When the read is complete, end_io_func() will be invoked with: + + (*) The netfs data supplied when the cookie was created. + + (*) The page descriptor. + + (*) The context argument passed to the above function. This will be + maintained with the get_context/put_context functions mentioned above. + + (*) An argument that's 0 on success or negative for an error code. + + If an error occurs, it should be assumed that the page contains no usable + data. + + end_io_func() will be called in process context if the read is results in + an error, but it might be called in interrupt context if the read is + successful. + +Otherwise, if there's not a copy available in cache, but the cache may be able +to store the page: + + (1) The mark_pages_cached() cookie operation will be called on that page. + + (2) A block may be reserved in the cache and attached to the object at the + appropriate place. + + (3) The function will return -ENODATA. + +This function may also return -ENOMEM or -EINTR, in which case it won't have +read any data from the cache. + + +PAGE ALLOCATE +------------- + +Alternatively, if there's not expected to be any data in the cache for a page +because the file has been extended, a block can simply be allocated instead: + + int fscache_alloc_page(struct fscache_cookie *cookie, + struct page *page, + gfp_t gfp); + +This is similar to the fscache_read_or_alloc_page() function, except that it +never reads from the cache. It will return 0 if a block has been allocated, +rather than -ENODATA as the other would. One or the other must be performed +before writing to the cache. + +The mark_pages_cached() cookie operation will be called on the page if +successful. + + +PAGE WRITE +---------- + +Secondly, if the netfs changes the contents of the page (either due to an +initial download or if a user performs a write), then the page should be +written back to the cache: + + int fscache_write_page(struct fscache_cookie *cookie, + struct page *page, + gfp_t gfp); + +The cookie argument must specify a data file cookie, the page specified should +contain the data to be written (and is also used to specify the page number), +and the gfp argument is used to control how any memory allocations made are +satisfied. + +The page must have first been read or allocated successfully and must not have +been uncached before writing is performed. + +If the cookie indicates the inode is not cached then: + + (1) The function will return -ENOBUFS. + +Else if space can be allocated in the cache to hold this page: + + (1) PG_fscache_write will be set on the page. + + (2) The function will submit a request to write the data to cache's backing + device directly from the page specified. + + (3) The function will return 0. + + (4) When the write is complete PG_fscache_write is cleared on the page and + anyone waiting for that bit will be woken up. + +Else if there's no space available in the cache, -ENOBUFS will be returned. It +is also possible for the PG_fscache_write bit to be cleared when no write took +place if unforeseen circumstances arose (such as a disk error). + +Writing takes place asynchronously. + + +MULTIPLE PAGE READ +------------------ + +A facility is provided to read several pages at once, as requested by the +readpages() address space operation: + + int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, + struct address_space *mapping, + struct list_head *pages, + int *nr_pages, + fscache_rw_complete_t end_io_func, + void *context, + gfp_t gfp); + +This works in a similar way to fscache_read_or_alloc_page(), except: + + (1) Any page it can retrieve data for is removed from pages and nr_pages and + dispatched for reading to the disk. Reads of adjacent pages on disk may + be merged for greater efficiency. + + (2) The mark_pages_cached() cookie operation will be called on several pages + at once if they're being read or allocated. + + (3) If there was an general error, then that error will be returned. + + Else if some pages couldn't be allocated or read, then -ENOBUFS will be + returned. + + Else if some pages couldn't be read but were allocated, then -ENODATA will + be returned. + + Otherwise, if all pages had reads dispatched, then 0 will be returned, the + list will be empty and *nr_pages will be 0. + + (4) end_io_func will be called once for each page being read as the reads + complete. It will be called in process context if error != 0, but it may + be called in interrupt context if there is no error. + +Note that a return of -ENODATA, -ENOBUFS or any other error does not preclude +some of the pages being read and some being allocated. Those pages will have +been marked appropriately and will need uncaching. + + +============== +PAGE UNCACHING +============== + +To uncache a page, this function should be called: + + void fscache_uncache_page(struct fscache_cookie *cookie, + struct page *page); + +This function permits the cache to release any in-memory representation it +might be holding for this netfs page. This function must be called once for +each page on which the read or write page functions above have been called to +make sure the cache's in-memory tracking information gets torn down. + +Note that pages can't be explicitly deleted from the a data file. The whole +data file must be retired (see the relinquish cookie function below). + +Furthermore, note that this does not cancel the asynchronous read or write +operation started by the read/alloc and write functions, so the page +invalidation and release functions must use: + + bool fscache_check_page_write(struct fscache_cookie *cookie, + struct page *page); + +to see if a page is being written to the cache, and: + + void fscache_wait_on_page_write(struct fscache_cookie *cookie, + struct page *page); + +to wait for it to finish if it is. + + +========================== +INDEX AND DATA FILE UPDATE +========================== + +To request an update of the index data for an index or other object, the +following function should be called: + + void fscache_update_cookie(struct fscache_cookie *cookie); + +This function will refer back to the netfs_data pointer stored in the cookie by +the acquisition function to obtain the data to write into each revised index +entry. The update method in the parent index definition will be called to +transfer the data. + +Note that partial updates may happen automatically at other times, such as when +data blocks are added to a data file object. + + +=============================== +MISCELLANEOUS COOKIE OPERATIONS +=============================== + +There are a number of operations that can be used to control cookies: + + (*) Cookie pinning: + + int fscache_pin_cookie(struct fscache_cookie *cookie); + void fscache_unpin_cookie(struct fscache_cookie *cookie); + + These operations permit data cookies to be pinned into the cache and to + have the pinning removed. They are not permitted on index cookies. + + The pinning function will return 0 if successful, -ENOBUFS in the cookie + isn't backed by a cache, -EOPNOTSUPP if the cache doesn't support pinning, + -ENOSPC if there isn't enough space to honour the operation, -ENOMEM or + -EIO if there's any other problem. + + (*) Data space reservation: + + int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size); + + This permits a netfs to request cache space be reserved to store up to the + given amount of a file. It is permitted to ask for more than the current + size of the file to allow for future file expansion. + + If size is given as zero then the reservation will be cancelled. + + The function will return 0 if successful, -ENOBUFS in the cookie isn't + backed by a cache, -EOPNOTSUPP if the cache doesn't support reservations, + -ENOSPC if there isn't enough space to honour the operation, -ENOMEM or + -EIO if there's any other problem. + + Note that this doesn't pin an object in a cache; it can still be culled to + make space if it's not in use. + + +===================== +COOKIE UNREGISTRATION +===================== + +To get rid of a cookie, this function should be called. + + void fscache_relinquish_cookie(struct fscache_cookie *cookie, + int retire); + +If retire is non-zero, then the object will be marked for recycling, and all +copies of it will be removed from all active caches in which it is present. +Not only that but all child objects will also be retired. + +If retire is zero, then the object may be available again when next the +acquisition function is called. Retirement here will overrule the pinning on a +cookie. + +One very important note - relinquish must NOT be called for a cookie unless all +the cookies for "child" indices, objects and pages have been relinquished +first. + + +================================ +INDEX AND DATA FILE INVALIDATION +================================ + +There is no direct way to invalidate an index subtree or a data file. To do +this, the caller should relinquish and retire the cookie they have, and then +acquire a new one. + + +=========================== +FS-CACHE SPECIFIC PAGE FLAG +=========================== + +FS-Cache makes use of a page flag, PG_private_2, for its own purpose. This is +given the alternative name PG_fscache. + +PG_fscache is used to indicate that the page is known by the cache, and that +the cache must be informed if the page is going to go away. It's an indication +to the netfs that the cache has an interest in this page, where an interest may +be a pointer to it, resources allocated or reserved for it, or I/O in progress +upon it. + +The netfs can use this information in methods such as releasepage() to +determine whether it needs to uncache a page or update it. + +Furthermore, if this bit is set, releasepage() and invalidatepage() operations +will be called on a page to get rid of it, even if PG_private is not set. This +allows caching to attempted on a page before read_cache_pages() to be called +after fscache_read_or_alloc_pages() as the former will try and release pages it +was given under certain circumstances. + +This bit does not overlap with such as PG_private. This means that FS-Cache +can be used with a filesystem that uses the block buffering code. + +There are a number of operations defined on this flag: + + int PageFsCache(struct page *page); + void SetPageFsCache(struct page *page) + void ClearPageFsCache(struct page *page) + int TestSetPageFsCache(struct page *page) + int TestClearPageFsCache(struct page *page) + +These functions are bit test, bit set, bit clear, bit test and set and bit +test and clear operations on PG_fscache. diff --git a/Documentation/filesystems/caching/object.txt b/Documentation/filesystems/caching/object.txt new file mode 100644 index 00000000000..e8b0a35d8fe --- /dev/null +++ b/Documentation/filesystems/caching/object.txt @@ -0,0 +1,313 @@ + ==================================================== + IN-KERNEL CACHE OBJECT REPRESENTATION AND MANAGEMENT + ==================================================== + +By: David Howells <dhowells@redhat.com> + +Contents: + + (*) Representation + + (*) Object management state machine. + + - Provision of cpu time. + - Locking simplification. + + (*) The set of states. + + (*) The set of events. + + +============== +REPRESENTATION +============== + +FS-Cache maintains an in-kernel representation of each object that a netfs is +currently interested in. Such objects are represented by the fscache_cookie +struct and are referred to as cookies. + +FS-Cache also maintains a separate in-kernel representation of the objects that +a cache backend is currently actively caching. Such objects are represented by +the fscache_object struct. The cache backends allocate these upon request, and +are expected to embed them in their own representations. These are referred to +as objects. + +There is a 1:N relationship between cookies and objects. A cookie may be +represented by multiple objects - an index may exist in more than one cache - +or even by no objects (it may not be cached). + +Furthermore, both cookies and objects are hierarchical. The two hierarchies +correspond, but the cookies tree is a superset of the union of the object trees +of multiple caches: + + NETFS INDEX TREE : CACHE 1 : CACHE 2 + : : + : +-----------+ : + +----------->| IObject | : + +-----------+ | : +-----------+ : + | ICookie |-------+ : | : + +-----------+ | : | : +-----------+ + | +------------------------------>| IObject | + | : | : +-----------+ + | : V : | + | : +-----------+ : | + V +----------->| IObject | : | + +-----------+ | : +-----------+ : | + | ICookie |-------+ : | : V + +-----------+ | : | : +-----------+ + | +------------------------------>| IObject | + +-----+-----+ : | : +-----------+ + | | : | : | + V | : V : | + +-----------+ | : +-----------+ : | + | ICookie |------------------------->| IObject | : | + +-----------+ | : +-----------+ : | + | V : | : V + | +-----------+ : | : +-----------+ + | | ICookie |-------------------------------->| IObject | + | +-----------+ : | : +-----------+ + V | : V : | + +-----------+ | : +-----------+ : | + | DCookie |------------------------->| DObject | : | + +-----------+ | : +-----------+ : | + | : : | + +-------+-------+ : : | + | | : : | + V V : : V + +-----------+ +-----------+ : : +-----------+ + | DCookie | | DCookie |------------------------>| DObject | + +-----------+ +-----------+ : : +-----------+ + : : + +In the above illustration, ICookie and IObject represent indices and DCookie +and DObject represent data storage objects. Indices may have representation in +multiple caches, but currently, non-index objects may not. Objects of any type +may also be entirely unrepresented. + +As far as the netfs API goes, the netfs is only actually permitted to see +pointers to the cookies. The cookies themselves and any objects attached to +those cookies are hidden from it. + + +=============================== +OBJECT MANAGEMENT STATE MACHINE +=============================== + +Within FS-Cache, each active object is managed by its own individual state +machine. The state for an object is kept in the fscache_object struct, in +object->state. A cookie may point to a set of objects that are in different +states. + +Each state has an action associated with it that is invoked when the machine +wakes up in that state. There are four logical sets of states: + + (1) Preparation: states that wait for the parent objects to become ready. The + representations are hierarchical, and it is expected that an object must + be created or accessed with respect to its parent object. + + (2) Initialisation: states that perform lookups in the cache and validate + what's found and that create on disk any missing metadata. + + (3) Normal running: states that allow netfs operations on objects to proceed + and that update the state of objects. + + (4) Termination: states that detach objects from their netfs cookies, that + delete objects from disk, that handle disk and system errors and that free + up in-memory resources. + + +In most cases, transitioning between states is in response to signalled events. +When a state has finished processing, it will usually set the mask of events in +which it is interested (object->event_mask) and relinquish the worker thread. +Then when an event is raised (by calling fscache_raise_event()), if the event +is not masked, the object will be queued for processing (by calling +fscache_enqueue_object()). + + +PROVISION OF CPU TIME +--------------------- + +The work to be done by the various states is given CPU time by the threads of +the slow work facility (see Documentation/slow-work.txt). This is used in +preference to the workqueue facility because: + + (1) Threads may be completely occupied for very long periods of time by a + particular work item. These state actions may be doing sequences of + synchronous, journalled disk accesses (lookup, mkdir, create, setxattr, + getxattr, truncate, unlink, rmdir, rename). + + (2) Threads may do little actual work, but may rather spend a lot of time + sleeping on I/O. This means that single-threaded and 1-per-CPU-threaded + workqueues don't necessarily have the right numbers of threads. + + +LOCKING SIMPLIFICATION +---------------------- + +Because only one worker thread may be operating on any particular object's +state machine at once, this simplifies the locking, particularly with respect +to disconnecting the netfs's representation of a cache object (fscache_cookie) +from the cache backend's representation (fscache_object) - which may be +requested from either end. + + +================= +THE SET OF STATES +================= + +The object state machine has a set of states that it can be in. There are +preparation states in which the object sets itself up and waits for its parent +object to transit to a state that allows access to its children: + + (1) State FSCACHE_OBJECT_INIT. + + Initialise the object and wait for the parent object to become active. In + the cache, it is expected that it will not be possible to look an object + up from the parent object, until that parent object itself has been looked + up. + +There are initialisation states in which the object sets itself up and accesses +disk for the object metadata: + + (2) State FSCACHE_OBJECT_LOOKING_UP. + + Look up the object on disk, using the parent as a starting point. + FS-Cache expects the cache backend to probe the cache to see whether this + object is represented there, and if it is, to see if it's valid (coherency + management). + + The cache should call fscache_object_lookup_negative() to indicate lookup + failure for whatever reason, and should call fscache_obtained_object() to + indicate success. + + At the completion of lookup, FS-Cache will let the netfs go ahead with + read operations, no matter whether the file is yet cached. If not yet + cached, read operations will be immediately rejected with ENODATA until + the first known page is uncached - as to that point there can be no data + to be read out of the cache for that file that isn't currently also held + in the pagecache. + + (3) State FSCACHE_OBJECT_CREATING. + + Create an object on disk, using the parent as a starting point. This + happens if the lookup failed to find the object, or if the object's + coherency data indicated what's on disk is out of date. In this state, + FS-Cache expects the cache to create + + The cache should call fscache_obtained_object() if creation completes + successfully, fscache_object_lookup_negative() otherwise. + + At the completion of creation, FS-Cache will start processing write + operations the netfs has queued for an object. If creation failed, the + write ops will be transparently discarded, and nothing recorded in the + cache. + +There are some normal running states in which the object spends its time +servicing netfs requests: + + (4) State FSCACHE_OBJECT_AVAILABLE. + + A transient state in which pending operations are started, child objects + are permitted to advance from FSCACHE_OBJECT_INIT state, and temporary + lookup data is freed. + + (5) State FSCACHE_OBJECT_ACTIVE. + + The normal running state. In this state, requests the netfs makes will be + passed on to the cache. + + (6) State FSCACHE_OBJECT_UPDATING. + + The state machine comes here to update the object in the cache from the + netfs's records. This involves updating the auxiliary data that is used + to maintain coherency. + +And there are terminal states in which an object cleans itself up, deallocates +memory and potentially deletes stuff from disk: + + (7) State FSCACHE_OBJECT_LC_DYING. + + The object comes here if it is dying because of a lookup or creation + error. This would be due to a disk error or system error of some sort. + Temporary data is cleaned up, and the parent is released. + + (8) State FSCACHE_OBJECT_DYING. + + The object comes here if it is dying due to an error, because its parent + cookie has been relinquished by the netfs or because the cache is being + withdrawn. + + Any child objects waiting on this one are given CPU time so that they too + can destroy themselves. This object waits for all its children to go away + before advancing to the next state. + + (9) State FSCACHE_OBJECT_ABORT_INIT. + + The object comes to this state if it was waiting on its parent in + FSCACHE_OBJECT_INIT, but its parent died. The object will destroy itself + so that the parent may proceed from the FSCACHE_OBJECT_DYING state. + +(10) State FSCACHE_OBJECT_RELEASING. +(11) State FSCACHE_OBJECT_RECYCLING. + + The object comes to one of these two states when dying once it is rid of + all its children, if it is dying because the netfs relinquished its + cookie. In the first state, the cached data is expected to persist, and + in the second it will be deleted. + +(12) State FSCACHE_OBJECT_WITHDRAWING. + + The object transits to this state if the cache decides it wants to + withdraw the object from service, perhaps to make space, but also due to + error or just because the whole cache is being withdrawn. + +(13) State FSCACHE_OBJECT_DEAD. + + The object transits to this state when the in-memory object record is + ready to be deleted. The object processor shouldn't ever see an object in + this state. + + +THE SET OF EVENTS +----------------- + +There are a number of events that can be raised to an object state machine: + + (*) FSCACHE_OBJECT_EV_UPDATE + + The netfs requested that an object be updated. The state machine will ask + the cache backend to update the object, and the cache backend will ask the + netfs for details of the change through its cookie definition ops. + + (*) FSCACHE_OBJECT_EV_CLEARED + + This is signalled in two circumstances: + + (a) when an object's last child object is dropped and + + (b) when the last operation outstanding on an object is completed. + + This is used to proceed from the dying state. + + (*) FSCACHE_OBJECT_EV_ERROR + + This is signalled when an I/O error occurs during the processing of some + object. + + (*) FSCACHE_OBJECT_EV_RELEASE + (*) FSCACHE_OBJECT_EV_RETIRE + + These are signalled when the netfs relinquishes a cookie it was using. + The event selected depends on whether the netfs asks for the backing + object to be retired (deleted) or retained. + + (*) FSCACHE_OBJECT_EV_WITHDRAW + + This is signalled when the cache backend wants to withdraw an object. + This means that the object will have to be detached from the netfs's + cookie. + +Because the withdrawing releasing/retiring events are all handled by the object +state machine, it doesn't matter if there's a collision with both ends trying +to sever the connection at the same time. The state machine can just pick +which one it wants to honour, and that effects the other. diff --git a/Documentation/filesystems/caching/operations.txt b/Documentation/filesystems/caching/operations.txt new file mode 100644 index 00000000000..b6b070c57cb --- /dev/null +++ b/Documentation/filesystems/caching/operations.txt @@ -0,0 +1,213 @@ + ================================ + ASYNCHRONOUS OPERATIONS HANDLING + ================================ + +By: David Howells <dhowells@redhat.com> + +Contents: + + (*) Overview. + + (*) Operation record initialisation. + + (*) Parameters. + + (*) Procedure. + + (*) Asynchronous callback. + + +======== +OVERVIEW +======== + +FS-Cache has an asynchronous operations handling facility that it uses for its +data storage and retrieval routines. Its operations are represented by +fscache_operation structs, though these are usually embedded into some other +structure. + +This facility is available to and expected to be be used by the cache backends, +and FS-Cache will create operations and pass them off to the appropriate cache +backend for completion. + +To make use of this facility, <linux/fscache-cache.h> should be #included. + + +=============================== +OPERATION RECORD INITIALISATION +=============================== + +An operation is recorded in an fscache_operation struct: + + struct fscache_operation { + union { + struct work_struct fast_work; + struct slow_work slow_work; + }; + unsigned long flags; + fscache_operation_processor_t processor; + ... + }; + +Someone wanting to issue an operation should allocate something with this +struct embedded in it. They should initialise it by calling: + + void fscache_operation_init(struct fscache_operation *op, + fscache_operation_release_t release); + +with the operation to be initialised and the release function to use. + +The op->flags parameter should be set to indicate the CPU time provision and +the exclusivity (see the Parameters section). + +The op->fast_work, op->slow_work and op->processor flags should be set as +appropriate for the CPU time provision (see the Parameters section). + +FSCACHE_OP_WAITING may be set in op->flags prior to each submission of the +operation and waited for afterwards. + + +========== +PARAMETERS +========== + +There are a number of parameters that can be set in the operation record's flag +parameter. There are three options for the provision of CPU time in these +operations: + + (1) The operation may be done synchronously (FSCACHE_OP_MYTHREAD). A thread + may decide it wants to handle an operation itself without deferring it to + another thread. + + This is, for example, used in read operations for calling readpages() on + the backing filesystem in CacheFiles. Although readpages() does an + asynchronous data fetch, the determination of whether pages exist is done + synchronously - and the netfs does not proceed until this has been + determined. + + If this option is to be used, FSCACHE_OP_WAITING must be set in op->flags + before submitting the operation, and the operating thread must wait for it + to be cleared before proceeding: + + wait_on_bit(&op->flags, FSCACHE_OP_WAITING, + fscache_wait_bit, TASK_UNINTERRUPTIBLE); + + + (2) The operation may be fast asynchronous (FSCACHE_OP_FAST), in which case it + will be given to keventd to process. Such an operation is not permitted + to sleep on I/O. + + This is, for example, used by CacheFiles to copy data from a backing fs + page to a netfs page after the backing fs has read the page in. + + If this option is used, op->fast_work and op->processor must be + initialised before submitting the operation: + + INIT_WORK(&op->fast_work, do_some_work); + + + (3) The operation may be slow asynchronous (FSCACHE_OP_SLOW), in which case it + will be given to the slow work facility to process. Such an operation is + permitted to sleep on I/O. + + This is, for example, used by FS-Cache to handle background writes of + pages that have just been fetched from a remote server. + + If this option is used, op->slow_work and op->processor must be + initialised before submitting the operation: + + fscache_operation_init_slow(op, processor) + + +Furthermore, operations may be one of two types: + + (1) Exclusive (FSCACHE_OP_EXCLUSIVE). Operations of this type may not run in + conjunction with any other operation on the object being operated upon. + + An example of this is the attribute change operation, in which the file + being written to may need truncation. + + (2) Shareable. Operations of this type may be running simultaneously. It's + up to the operation implementation to prevent interference between other + operations running at the same time. + + +========= +PROCEDURE +========= + +Operations are used through the following procedure: + + (1) The submitting thread must allocate the operation and initialise it + itself. Normally this would be part of a more specific structure with the + generic op embedded within. + + (2) The submitting thread must then submit the operation for processing using + one of the following two functions: + + int fscache_submit_op(struct fscache_object *object, + struct fscache_operation *op); + + int fscache_submit_exclusive_op(struct fscache_object *object, + struct fscache_operation *op); + + The first function should be used to submit non-exclusive ops and the + second to submit exclusive ones. The caller must still set the + FSCACHE_OP_EXCLUSIVE flag. + + If successful, both functions will assign the operation to the specified + object and return 0. -ENOBUFS will be returned if the object specified is + permanently unavailable. + + The operation manager will defer operations on an object that is still + undergoing lookup or creation. The operation will also be deferred if an + operation of conflicting exclusivity is in progress on the object. + + If the operation is asynchronous, the manager will retain a reference to + it, so the caller should put their reference to it by passing it to: + + void fscache_put_operation(struct fscache_operation *op); + + (3) If the submitting thread wants to do the work itself, and has marked the + operation with FSCACHE_OP_MYTHREAD, then it should monitor + FSCACHE_OP_WAITING as described above and check the state of the object if + necessary (the object might have died whilst the thread was waiting). + + When it has finished doing its processing, it should call + fscache_put_operation() on it. + + (4) The operation holds an effective lock upon the object, preventing other + exclusive ops conflicting until it is released. The operation can be + enqueued for further immediate asynchronous processing by adjusting the + CPU time provisioning option if necessary, eg: + + op->flags &= ~FSCACHE_OP_TYPE; + op->flags |= ~FSCACHE_OP_FAST; + + and calling: + + void fscache_enqueue_operation(struct fscache_operation *op) + + This can be used to allow other things to have use of the worker thread + pools. + + +===================== +ASYNCHRONOUS CALLBACK +===================== + +When used in asynchronous mode, the worker thread pool will invoke the +processor method with a pointer to the operation. This should then get at the +container struct by using container_of(): + + static void fscache_write_op(struct fscache_operation *_op) + { + struct fscache_storage *op = + container_of(_op, struct fscache_storage, op); + ... + } + +The caller holds a reference on the operation, and will invoke +fscache_put_operation() when the processor function returns. The processor +function is at liberty to call fscache_enqueue_operation() or to take extra +references. diff --git a/Documentation/filesystems/exofs.txt b/Documentation/filesystems/exofs.txt new file mode 100644 index 00000000000..0ced74c2f73 --- /dev/null +++ b/Documentation/filesystems/exofs.txt @@ -0,0 +1,176 @@ +=============================================================================== +WHAT IS EXOFS? +=============================================================================== + +exofs is a file system that uses an OSD and exports the API of a normal Linux +file system. Users access exofs like any other local file system, and exofs +will in turn issue commands to the local OSD initiator. + +OSD is a new T10 command set that views storage devices not as a large/flat +array of sectors but as a container of objects, each having a length, quota, +time attributes and more. Each object is addressed by a 64bit ID, and is +contained in a 64bit ID partition. Each object has associated attributes +attached to it, which are integral part of the object and provide metadata about +the object. The standard defines some common obligatory attributes, but user +attributes can be added as needed. + +=============================================================================== +ENVIRONMENT +=============================================================================== + +To use this file system, you need to have an object store to run it on. You +may download a target from: +http://open-osd.org + +See Documentation/scsi/osd.txt for how to setup a working osd environment. + +=============================================================================== +USAGE +=============================================================================== + +1. Download and compile exofs and open-osd initiator: + You need an external Kernel source tree or kernel headers from your + distribution. (anything based on 2.6.26 or later). + + a. download open-osd including exofs source using: + [parent-directory]$ git clone git://git.open-osd.org/open-osd.git + + b. Build the library module like this: + [parent-directory]$ make -C KSRC=$(KER_DIR) open-osd + + This will build both the open-osd initiator as well as the exofs kernel + module. Use whatever parameters you compiled your Kernel with and + $(KER_DIR) above pointing to the Kernel you compile against. See the file + open-osd/top-level-Makefile for an example. + +2. Get the OSD initiator and target set up properly, and login to the target. + See Documentation/scsi/osd.txt for farther instructions. Also see ./do-osd + for example script that does all these steps. + +3. Insmod the exofs.ko module: + [exofs]$ insmod exofs.ko + +4. Make sure the directory where you want to mount exists. If not, create it. + (For example, mkdir /mnt/exofs) + +5. At first run you will need to invoke the mkfs.exofs application + + As an example, this will create the file system on: + /dev/osd0 partition ID 65536 + + mkfs.exofs --pid=65536 --format /dev/osd0 + + The --format is optional if not specified no OSD_FORMAT will be + preformed and a clean file system will be created in the specified pid, + in the available space of the target. (Use --format=size_in_meg to limit + the total LUN space available) + + If pid already exist it will be deleted and a new one will be created in it's + place. Be careful. + + An exofs lives inside a single OSD partition. You can create multiple exofs + filesystems on the same device using multiple pids. + + (run mkfs.exofs without any parameters for usage help message) + +6. Mount the file system. + + For example, to mount /dev/osd0, partition ID 0x10000 on /mnt/exofs: + + mount -t exofs -o pid=65536 /dev/osd0 /mnt/exofs/ + +7. For reference (See do-exofs example script): + do-exofs start - an example of how to perform the above steps. + do-exofs stop - an example of how to unmount the file system. + do-exofs format - an example of how to format and mkfs a new exofs. + +8. Extra compilation flags (uncomment in fs/exofs/Kbuild): + CONFIG_EXOFS_DEBUG - for debug messages and extra checks. + +=============================================================================== +exofs mount options +=============================================================================== +Similar to any mount command: + mount -t exofs -o exofs_options /dev/osdX mount_exofs_directory + +Where: + -t exofs: specifies the exofs file system + + /dev/osdX: X is a decimal number. /dev/osdX was created after a successful + login into an OSD target. + + mount_exofs_directory: The directory to mount the file system on + + exofs specific options: Options are separated by commas (,) + pid=<integer> - The partition number to mount/create as + container of the filesystem. + This option is mandatory + to=<integer> - Timeout in ticks for a single command + default is (60 * HZ) [for debugging only] + +=============================================================================== +DESIGN +=============================================================================== + +* The file system control block (AKA on-disk superblock) resides in an object + with a special ID (defined in common.h). + Information included in the file system control block is used to fill the + in-memory superblock structure at mount time. This object is created before + the file system is used by mkexofs.c It contains information such as: + - The file system's magic number + - The next inode number to be allocated + +* Each file resides in its own object and contains the data (and it will be + possible to extend the file over multiple objects, though this has not been + implemented yet). + +* A directory is treated as a file, and essentially contains a list of <file + name, inode #> pairs for files that are found in that directory. The object + IDs correspond to the files' inode numbers and will be allocated according to + a bitmap (stored in a separate object). Now they are allocated using a + counter. + +* Each file's control block (AKA on-disk inode) is stored in its object's + attributes. This applies to both regular files and other types (directories, + device files, symlinks, etc.). + +* Credentials are generated per object (inode and superblock) when they is + created in memory (read off disk or created). The credential works for all + operations and is used as long as the object remains in memory. + +* Async OSD operations are used whenever possible, but the target may execute + them out of order. The operations that concern us are create, delete, + readpage, writepage, update_inode, and truncate. The following pairs of + operations should execute in the order written, and we need to prevent them + from executing in reverse order: + - The following are handled with the OBJ_CREATED and OBJ_2BCREATED + flags. OBJ_CREATED is set when we know the object exists on the OSD - + in create's callback function, and when we successfully do a read_inode. + OBJ_2BCREATED is set in the beginning of the create function, so we + know that we should wait. + - create/delete: delete should wait until the object is created + on the OSD. + - create/readpage: readpage should be able to return a page + full of zeroes in this case. If there was a write already + en-route (i.e. create, writepage, readpage) then the page + would be locked, and so it would really be the same as + create/writepage. + - create/writepage: if writepage is called for a sync write, it + should wait until the object is created on the OSD. + Otherwise, it should just return. + - create/truncate: truncate should wait until the object is + created on the OSD. + - create/update_inode: update_inode should wait until the + object is created on the OSD. + - Handled by VFS locks: + - readpage/delete: shouldn't happen because of page lock. + - writepage/delete: shouldn't happen because of page lock. + - readpage/writepage: shouldn't happen because of page lock. + +=============================================================================== +LICENSE/COPYRIGHT +=============================================================================== +The exofs file system is based on ext2 v0.5b (distributed with the Linux kernel +version 2.6.10). All files include the original copyrights, and the license +is GPL version 2 (only version 2, as is true for the Linux kernel). The +Linux kernel can be downloaded from www.kernel.org. diff --git a/Documentation/filesystems/ext3.txt b/Documentation/filesystems/ext3.txt index e5f3833a6ef..570f9bd9be2 100644 --- a/Documentation/filesystems/ext3.txt +++ b/Documentation/filesystems/ext3.txt @@ -14,6 +14,11 @@ Options When mounting an ext3 filesystem, the following option are accepted: (*) == default +ro Mount filesystem read only. Note that ext3 will replay + the journal (and thus write to the partition) even when + mounted "read only". Mount options "ro,noload" can be + used to prevent writes to the filesystem. + journal=update Update the ext3 file system's journal to the current format. @@ -27,7 +32,9 @@ journal_dev=devnum When the external journal device's major/minor numbers identified through its new major/minor numbers encoded in devnum. -noload Don't load the journal on mounting. +noload Don't load the journal on mounting. Note that this forces + mount of inconsistent filesystem, which can lead to + various problems. data=journal All data are committed into the journal prior to being written into the main file system. @@ -92,9 +99,12 @@ nocheck debug Extra debugging information is sent to syslog. -errors=remount-ro(*) Remount the filesystem read-only on an error. +errors=remount-ro Remount the filesystem read-only on an error. errors=continue Keep going on a filesystem error. errors=panic Panic and halt the machine if an error occurs. + (These mount options override the errors behavior + specified in the superblock, which can be + configured using tune2fs.) data_err=ignore(*) Just print an error message if an error occurs in a file data buffer in ordered mode. diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index cec829bc729..97882df0486 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -85,7 +85,7 @@ Note: More extensive information for getting started with ext4 can be * extent format more robust in face of on-disk corruption due to magics, * internal redundancy in tree * improved file allocation (multi-block alloc) -* fix 32000 subdirectory limit +* lift 32000 subdirectory limit imposed by i_links_count[1] * nsec timestamps for mtime, atime, ctime, create time * inode version field on disk (NFSv4, Lustre) * reduced e2fsck time via uninit_bg feature @@ -100,6 +100,9 @@ Note: More extensive information for getting started with ext4 can be * efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force the ordering) +[1] Filesystems with a block size of 1k may see a limit imposed by the +directory hash tree having a maximum depth of two. + 2.2 Candidate features for future inclusion * Online defrag (patches available but not well tested) @@ -180,8 +183,8 @@ commit=nrsec (*) Ext4 can be told to sync all its data and metadata performance. barrier=<0|1(*)> This enables/disables the use of write barriers in - the jbd code. barrier=0 disables, barrier=1 enables. - This also requires an IO stack which can support +barrier(*) the jbd code. barrier=0 disables, barrier=1 enables. +nobarrier This also requires an IO stack which can support barriers, and if jbd gets an error on a barrier write, it will disable again with a warning. Write barriers enforce proper on-disk ordering @@ -189,6 +192,9 @@ barrier=<0|1(*)> This enables/disables the use of write barriers in safe to use, at some performance penalty. If your disks are battery-backed in one way or another, disabling barriers may safely improve performance. + The mount options "barrier" and "nobarrier" can + also be used to enable or disable barriers, for + consistency with other ext4 mount options. inode_readahead=n This tuning parameter controls the maximum number of inode table blocks that ext4's inode @@ -310,6 +316,24 @@ journal_ioprio=prio The I/O priority (from 0 to 7, where 0 is the a slightly higher priority than the default I/O priority. +auto_da_alloc(*) Many broken applications don't use fsync() when +noauto_da_alloc replacing existing files via patterns such as + fd = open("foo.new")/write(fd,..)/close(fd)/ + rename("foo.new", "foo"), or worse yet, + fd = open("foo", O_TRUNC)/write(fd,..)/close(fd). + If auto_da_alloc is enabled, ext4 will detect + the replace-via-rename and replace-via-truncate + patterns and force that any delayed allocation + blocks are allocated such that at the next + journal commit, in the default data=ordered + mode, the data blocks of the new file are forced + to disk before the rename() operation is + commited. This provides roughly the same level + of guarantees as ext3, and avoids the + "zero-length" problem that can happen when a + system crashes before the delayed allocation + blocks are forced to disk. + Data Mode ========= There are 3 different data modes: diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 830bad7cce0..ce84cfc9eae 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -5,6 +5,7 @@ Bodo Bauer <bb@ricochet.net> 2.4.x update Jorge Nerin <comandante@zaralinux.com> November 14 2000 +move /proc/sys Shen Feng <shen@cn.fujitsu.com> April 1 2009 ------------------------------------------------------------------------------ Version 1.3 Kernel version 2.2.12 Kernel version 2.4.0-test11-pre4 @@ -26,25 +27,17 @@ Table of Contents 1.6 Parallel port info in /proc/parport 1.7 TTY info in /proc/tty 1.8 Miscellaneous kernel statistics in /proc/stat + 1.9 Ext4 file system parameters 2 Modifying System Parameters - 2.1 /proc/sys/fs - File system data - 2.2 /proc/sys/fs/binfmt_misc - Miscellaneous binary formats - 2.3 /proc/sys/kernel - general kernel parameters - 2.4 /proc/sys/vm - The virtual memory subsystem - 2.5 /proc/sys/dev - Device specific parameters - 2.6 /proc/sys/sunrpc - Remote procedure calls - 2.7 /proc/sys/net - Networking stuff - 2.8 /proc/sys/net/ipv4 - IPV4 settings - 2.9 Appletalk - 2.10 IPX - 2.11 /proc/sys/fs/mqueue - POSIX message queues filesystem - 2.12 /proc/<pid>/oom_adj - Adjust the oom-killer score - 2.13 /proc/<pid>/oom_score - Display current oom-killer score - 2.14 /proc/<pid>/io - Display the IO accounting fields - 2.15 /proc/<pid>/coredump_filter - Core dump filtering settings - 2.16 /proc/<pid>/mountinfo - Information about mounts - 2.17 /proc/sys/fs/epoll - Configuration options for the epoll interface + + 3 Per-Process Parameters + 3.1 /proc/<pid>/oom_adj - Adjust the oom-killer score + 3.2 /proc/<pid>/oom_score - Display current oom-killer score + 3.3 /proc/<pid>/io - Display the IO accounting fields + 3.4 /proc/<pid>/coredump_filter - Core dump filtering settings + 3.5 /proc/<pid>/mountinfo - Information about mounts + ------------------------------------------------------------------------------ Preface @@ -940,27 +933,6 @@ Table 1-10: Files in /proc/fs/ext4/<devname> File Content mb_groups details of multiblock allocator buddy cache of free blocks mb_history multiblock allocation history - stats controls whether the multiblock allocator should start - collecting statistics, which are shown during the unmount - group_prealloc the multiblock allocator will round up allocation - requests to a multiple of this tuning parameter if the - stripe size is not set in the ext4 superblock - max_to_scan The maximum number of extents the multiblock allocator - will search to find the best extent - min_to_scan The minimum number of extents the multiblock allocator - will search to find the best extent - order2_req Tuning parameter which controls the minimum size for - requests (as a power of 2) where the buddy cache is - used - stream_req Files which have fewer blocks than this tunable - parameter will have their blocks allocated out of a - block group specific preallocation pool, so that small - files are packed closely together. Each large file - will have its blocks allocated out of its own unique - preallocation pool. -inode_readahead Tuning parameter which controls the maximum number of - inode table blocks that ext4's inode table readahead - algorithm will pre-read into the buffer cache .............................................................................. @@ -1011,1021 +983,24 @@ review the kernel documentation in the directory /usr/src/linux/Documentation. This chapter is heavily based on the documentation included in the pre 2.2 kernels, and became part of it in version 2.2.1 of the Linux kernel. -2.1 /proc/sys/fs - File system data ------------------------------------ - -This subdirectory contains specific file system, file handle, inode, dentry -and quota information. - -Currently, these files are in /proc/sys/fs: - -dentry-state ------------- - -Status of the directory cache. Since directory entries are dynamically -allocated and deallocated, this file indicates the current status. It holds -six values, in which the last two are not used and are always zero. The others -are listed in table 2-1. - - -Table 2-1: Status files of the directory cache -.............................................................................. - File Content - nr_dentry Almost always zero - nr_unused Number of unused cache entries - age_limit - in seconds after the entry may be reclaimed, when memory is short - want_pages internally -.............................................................................. - -dquot-nr and dquot-max ----------------------- - -The file dquot-max shows the maximum number of cached disk quota entries. - -The file dquot-nr shows the number of allocated disk quota entries and the -number of free disk quota entries. - -If the number of available cached disk quotas is very low and you have a large -number of simultaneous system users, you might want to raise the limit. - -file-nr and file-max --------------------- - -The kernel allocates file handles dynamically, but doesn't free them again at -this time. - -The value in file-max denotes the maximum number of file handles that the -Linux kernel will allocate. When you get a lot of error messages about running -out of file handles, you might want to raise this limit. The default value is -10% of RAM in kilobytes. To change it, just write the new number into the -file: - - # cat /proc/sys/fs/file-max - 4096 - # echo 8192 > /proc/sys/fs/file-max - # cat /proc/sys/fs/file-max - 8192 - - -This method of revision is useful for all customizable parameters of the -kernel - simply echo the new value to the corresponding file. - -Historically, the three values in file-nr denoted the number of allocated file -handles, the number of allocated but unused file handles, and the maximum -number of file handles. Linux 2.6 always reports 0 as the number of free file -handles -- this is not an error, it just means that the number of allocated -file handles exactly matches the number of used file handles. - -Attempts to allocate more file descriptors than file-max are reported with -printk, look for "VFS: file-max limit <number> reached". - -inode-state and inode-nr ------------------------- - -The file inode-nr contains the first two items from inode-state, so we'll skip -to that file... - -inode-state contains two actual numbers and five dummy values. The numbers -are nr_inodes and nr_free_inodes (in order of appearance). - -nr_inodes -~~~~~~~~~ - -Denotes the number of inodes the system has allocated. This number will -grow and shrink dynamically. - -nr_open -------- - -Denotes the maximum number of file-handles a process can -allocate. Default value is 1024*1024 (1048576) which should be -enough for most machines. Actual limit depends on RLIMIT_NOFILE -resource limit. - -nr_free_inodes --------------- - -Represents the number of free inodes. Ie. The number of inuse inodes is -(nr_inodes - nr_free_inodes). - -aio-nr and aio-max-nr ---------------------- - -aio-nr is the running total of the number of events specified on the -io_setup system call for all currently active aio contexts. If aio-nr -reaches aio-max-nr then io_setup will fail with EAGAIN. Note that -raising aio-max-nr does not result in the pre-allocation or re-sizing -of any kernel data structures. - -2.2 /proc/sys/fs/binfmt_misc - Miscellaneous binary formats ------------------------------------------------------------ - -Besides these files, there is the subdirectory /proc/sys/fs/binfmt_misc. This -handles the kernel support for miscellaneous binary formats. - -Binfmt_misc provides the ability to register additional binary formats to the -Kernel without compiling an additional module/kernel. Therefore, binfmt_misc -needs to know magic numbers at the beginning or the filename extension of the -binary. - -It works by maintaining a linked list of structs that contain a description of -a binary format, including a magic with size (or the filename extension), -offset and mask, and the interpreter name. On request it invokes the given -interpreter with the original program as argument, as binfmt_java and -binfmt_em86 and binfmt_mz do. Since binfmt_misc does not define any default -binary-formats, you have to register an additional binary-format. - -There are two general files in binfmt_misc and one file per registered format. -The two general files are register and status. - -Registering a new binary format -------------------------------- - -To register a new binary format you have to issue the command - - echo :name:type:offset:magic:mask:interpreter: > /proc/sys/fs/binfmt_misc/register - - - -with appropriate name (the name for the /proc-dir entry), offset (defaults to -0, if omitted), magic, mask (which can be omitted, defaults to all 0xff) and -last but not least, the interpreter that is to be invoked (for example and -testing /bin/echo). Type can be M for usual magic matching or E for filename -extension matching (give extension in place of magic). - -Check or reset the status of the binary format handler ------------------------------------------------------- - -If you do a cat on the file /proc/sys/fs/binfmt_misc/status, you will get the -current status (enabled/disabled) of binfmt_misc. Change the status by echoing -0 (disables) or 1 (enables) or -1 (caution: this clears all previously -registered binary formats) to status. For example echo 0 > status to disable -binfmt_misc (temporarily). - -Status of a single handler --------------------------- - -Each registered handler has an entry in /proc/sys/fs/binfmt_misc. These files -perform the same function as status, but their scope is limited to the actual -binary format. By cating this file, you also receive all related information -about the interpreter/magic of the binfmt. - -Example usage of binfmt_misc (emulate binfmt_java) --------------------------------------------------- - - cd /proc/sys/fs/binfmt_misc - echo ':Java:M::\xca\xfe\xba\xbe::/usr/local/java/bin/javawrapper:' > register - echo ':HTML:E::html::/usr/local/java/bin/appletviewer:' > register - echo ':Applet:M::<!--applet::/usr/local/java/bin/appletviewer:' > register - echo ':DEXE:M::\x0eDEX::/usr/bin/dosexec:' > register - - -These four lines add support for Java executables and Java applets (like -binfmt_java, additionally recognizing the .html extension with no need to put -<!--applet> to every applet file). You have to install the JDK and the -shell-script /usr/local/java/bin/javawrapper too. It works around the -brokenness of the Java filename handling. To add a Java binary, just create a -link to the class-file somewhere in the path. - -2.3 /proc/sys/kernel - general kernel parameters ------------------------------------------------- - -This directory reflects general kernel behaviors. As I've said before, the -contents depend on your configuration. Here you'll find the most important -files, along with descriptions of what they mean and how to use them. - -acct ----- - -The file contains three values; highwater, lowwater, and frequency. - -It exists only when BSD-style process accounting is enabled. These values -control its behavior. If the free space on the file system where the log lives -goes below lowwater percentage, accounting suspends. If it goes above -highwater percentage, accounting resumes. Frequency determines how often you -check the amount of free space (value is in seconds). Default settings are: 4, -2, and 30. That is, suspend accounting if there is less than 2 percent free; -resume it if we have a value of 3 or more percent; consider information about -the amount of free space valid for 30 seconds - -ctrl-alt-del ------------- - -When the value in this file is 0, ctrl-alt-del is trapped and sent to the init -program to handle a graceful restart. However, when the value is greater that -zero, Linux's reaction to this key combination will be an immediate reboot, -without syncing its dirty buffers. - -[NOTE] - When a program (like dosemu) has the keyboard in raw mode, the - ctrl-alt-del is intercepted by the program before it ever reaches the - kernel tty layer, and it is up to the program to decide what to do with - it. - -domainname and hostname ------------------------ - -These files can be controlled to set the NIS domainname and hostname of your -box. For the classic darkstar.frop.org a simple: - - # echo "darkstar" > /proc/sys/kernel/hostname - # echo "frop.org" > /proc/sys/kernel/domainname - - -would suffice to set your hostname and NIS domainname. - -osrelease, ostype and version ------------------------------ - -The names make it pretty obvious what these fields contain: - - > cat /proc/sys/kernel/osrelease - 2.2.12 - - > cat /proc/sys/kernel/ostype - Linux - - > cat /proc/sys/kernel/version - #4 Fri Oct 1 12:41:14 PDT 1999 - - -The files osrelease and ostype should be clear enough. Version needs a little -more clarification. The #4 means that this is the 4th kernel built from this -source base and the date after it indicates the time the kernel was built. The -only way to tune these values is to rebuild the kernel. - -panic ------ - -The value in this file represents the number of seconds the kernel waits -before rebooting on a panic. When you use the software watchdog, the -recommended setting is 60. If set to 0, the auto reboot after a kernel panic -is disabled, which is the default setting. - -printk ------- - -The four values in printk denote -* console_loglevel, -* default_message_loglevel, -* minimum_console_loglevel and -* default_console_loglevel -respectively. - -These values influence printk() behavior when printing or logging error -messages, which come from inside the kernel. See syslog(2) for more -information on the different log levels. - -console_loglevel ----------------- - -Messages with a higher priority than this will be printed to the console. - -default_message_level ---------------------- - -Messages without an explicit priority will be printed with this priority. - -minimum_console_loglevel ------------------------- - -Minimum (highest) value to which the console_loglevel can be set. - -default_console_loglevel ------------------------- - -Default value for console_loglevel. - -sg-big-buff ------------ - -This file shows the size of the generic SCSI (sg) buffer. At this point, you -can't tune it yet, but you can change it at compile time by editing -include/scsi/sg.h and changing the value of SG_BIG_BUFF. - -If you use a scanner with SANE (Scanner Access Now Easy) you might want to set -this to a higher value. Refer to the SANE documentation on this issue. - -modprobe --------- - -The location where the modprobe binary is located. The kernel uses this -program to load modules on demand. - -unknown_nmi_panic ------------------ - -The value in this file affects behavior of handling NMI. When the value is -non-zero, unknown NMI is trapped and then panic occurs. At that time, kernel -debugging information is displayed on console. - -NMI switch that most IA32 servers have fires unknown NMI up, for example. -If a system hangs up, try pressing the NMI switch. - -panic_on_unrecovered_nmi ------------------------- - -The default Linux behaviour on an NMI of either memory or unknown is to continue -operation. For many environments such as scientific computing it is preferable -that the box is taken out and the error dealt with than an uncorrected -parity/ECC error get propogated. - -A small number of systems do generate NMI's for bizarre random reasons such as -power management so the default is off. That sysctl works like the existing -panic controls already in that directory. - -nmi_watchdog ------------- - -Enables/Disables the NMI watchdog on x86 systems. When the value is non-zero -the NMI watchdog is enabled and will continuously test all online cpus to -determine whether or not they are still functioning properly. Currently, -passing "nmi_watchdog=" parameter at boot time is required for this function -to work. - -If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel parameter), the -NMI watchdog shares registers with oprofile. By disabling the NMI watchdog, -oprofile may have more registers to utilize. - -msgmni ------- - -Maximum number of message queue ids on the system. -This value scales to the amount of lowmem. It is automatically recomputed -upon memory add/remove or ipc namespace creation/removal. -When a value is written into this file, msgmni's value becomes fixed, i.e. it -is not recomputed anymore when one of the above events occurs. -Use auto_msgmni to change this behavior. - -auto_msgmni ------------ - -Enables/Disables automatic recomputing of msgmni upon memory add/remove or -upon ipc namespace creation/removal (see the msgmni description above). -Echoing "1" into this file enables msgmni automatic recomputing. -Echoing "0" turns it off. -auto_msgmni default value is 1. - - -2.4 /proc/sys/vm - The virtual memory subsystem ------------------------------------------------ - -Please see: Documentation/sysctls/vm.txt for a description of these +Please see: Documentation/sysctls/ directory for descriptions of these entries. +------------------------------------------------------------------------------ +Summary +------------------------------------------------------------------------------ +Certain aspects of kernel behavior can be modified at runtime, without the +need to recompile the kernel, or even to reboot the system. The files in the +/proc/sys tree can not only be read, but also modified. You can use the echo +command to write value into these files, thereby changing the default settings +of the kernel. +------------------------------------------------------------------------------ -2.5 /proc/sys/dev - Device specific parameters ----------------------------------------------- - -Currently there is only support for CDROM drives, and for those, there is only -one read-only file containing information about the CD-ROM drives attached to -the system: - - >cat /proc/sys/dev/cdrom/info - CD-ROM information, Id: cdrom.c 2.55 1999/04/25 - - drive name: sr0 hdb - drive speed: 32 40 - drive # of slots: 1 0 - Can close tray: 1 1 - Can open tray: 1 1 - Can lock tray: 1 1 - Can change speed: 1 1 - Can select disk: 0 1 - Can read multisession: 1 1 - Can read MCN: 1 1 - Reports media changed: 1 1 - Can play audio: 1 1 - - -You see two drives, sr0 and hdb, along with a list of their features. - -2.6 /proc/sys/sunrpc - Remote procedure calls ---------------------------------------------- - -This directory contains four files, which enable or disable debugging for the -RPC functions NFS, NFS-daemon, RPC and NLM. The default values are 0. They can -be set to one to turn debugging on. (The default value is 0 for each) - -2.7 /proc/sys/net - Networking stuff ------------------------------------- - -The interface to the networking parts of the kernel is located in -/proc/sys/net. Table 2-3 shows all possible subdirectories. You may see only -some of them, depending on your kernel's configuration. - - -Table 2-3: Subdirectories in /proc/sys/net -.............................................................................. - Directory Content Directory Content - core General parameter appletalk Appletalk protocol - unix Unix domain sockets netrom NET/ROM - 802 E802 protocol ax25 AX25 - ethernet Ethernet protocol rose X.25 PLP layer - ipv4 IP version 4 x25 X.25 protocol - ipx IPX token-ring IBM token ring - bridge Bridging decnet DEC net - ipv6 IP version 6 -.............................................................................. - -We will concentrate on IP networking here. Since AX15, X.25, and DEC Net are -only minor players in the Linux world, we'll skip them in this chapter. You'll -find some short info on Appletalk and IPX further on in this chapter. Review -the online documentation and the kernel source to get a detailed view of the -parameters for those protocols. In this section we'll discuss the -subdirectories printed in bold letters in the table above. As default values -are suitable for most needs, there is no need to change these values. - -/proc/sys/net/core - Network core options ------------------------------------------ - -rmem_default ------------- - -The default setting of the socket receive buffer in bytes. - -rmem_max --------- - -The maximum receive socket buffer size in bytes. - -wmem_default ------------- - -The default setting (in bytes) of the socket send buffer. - -wmem_max --------- - -The maximum send socket buffer size in bytes. - -message_burst and message_cost ------------------------------- - -These parameters are used to limit the warning messages written to the kernel -log from the networking code. They enforce a rate limit to make a -denial-of-service attack impossible. A higher message_cost factor, results in -fewer messages that will be written. Message_burst controls when messages will -be dropped. The default settings limit warning messages to one every five -seconds. - -warnings --------- - -This controls console messages from the networking stack that can occur because -of problems on the network like duplicate address or bad checksums. Normally, -this should be enabled, but if the problem persists the messages can be -disabled. - -netdev_budget -------------- - -Maximum number of packets taken from all interfaces in one polling cycle (NAPI -poll). In one polling cycle interfaces which are registered to polling are -probed in a round-robin manner. The limit of packets in one such probe can be -set per-device via sysfs class/net/<device>/weight . - -netdev_max_backlog ------------------- - -Maximum number of packets, queued on the INPUT side, when the interface -receives packets faster than kernel can process them. - -optmem_max ----------- - -Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence -of struct cmsghdr structures with appended data. - -/proc/sys/net/unix - Parameters for Unix domain sockets -------------------------------------------------------- - -There are only two files in this subdirectory. They control the delays for -deleting and destroying socket descriptors. - -2.8 /proc/sys/net/ipv4 - IPV4 settings --------------------------------------- - -IP version 4 is still the most used protocol in Unix networking. It will be -replaced by IP version 6 in the next couple of years, but for the moment it's -the de facto standard for the internet and is used in most networking -environments around the world. Because of the importance of this protocol, -we'll have a deeper look into the subtree controlling the behavior of the IPv4 -subsystem of the Linux kernel. - -Let's start with the entries in /proc/sys/net/ipv4. - -ICMP settings -------------- - -icmp_echo_ignore_all and icmp_echo_ignore_broadcasts ----------------------------------------------------- - -Turn on (1) or off (0), if the kernel should ignore all ICMP ECHO requests, or -just those to broadcast and multicast addresses. - -Please note that if you accept ICMP echo requests with a broadcast/multi\-cast -destination address your network may be used as an exploder for denial of -service packet flooding attacks to other hosts. - -icmp_destunreach_rate, icmp_echoreply_rate, icmp_paramprob_rate and icmp_timeexeed_rate ---------------------------------------------------------------------------------------- - -Sets limits for sending ICMP packets to specific targets. A value of zero -disables all limiting. Any positive value sets the maximum package rate in -hundredth of a second (on Intel systems). - -IP settings ------------ - -ip_autoconfig -------------- - -This file contains the number one if the host received its IP configuration by -RARP, BOOTP, DHCP or a similar mechanism. Otherwise it is zero. - -ip_default_ttl --------------- - -TTL (Time To Live) for IPv4 interfaces. This is simply the maximum number of -hops a packet may travel. - -ip_dynaddr ----------- - -Enable dynamic socket address rewriting on interface address change. This is -useful for dialup interface with changing IP addresses. - -ip_forward ----------- - -Enable or disable forwarding of IP packages between interfaces. Changing this -value resets all other parameters to their default values. They differ if the -kernel is configured as host or router. - -ip_local_port_range -------------------- - -Range of ports used by TCP and UDP to choose the local port. Contains two -numbers, the first number is the lowest port, the second number the highest -local port. Default is 1024-4999. Should be changed to 32768-61000 for -high-usage systems. - -ip_no_pmtu_disc ---------------- - -Global switch to turn path MTU discovery off. It can also be set on a per -socket basis by the applications or on a per route basis. - -ip_masq_debug -------------- - -Enable/disable debugging of IP masquerading. - -IP fragmentation settings -------------------------- - -ipfrag_high_trash and ipfrag_low_trash --------------------------------------- - -Maximum memory used to reassemble IP fragments. When ipfrag_high_thresh bytes -of memory is allocated for this purpose, the fragment handler will toss -packets until ipfrag_low_thresh is reached. - -ipfrag_time ------------ - -Time in seconds to keep an IP fragment in memory. - -TCP settings ------------- - -tcp_ecn -------- - -This file controls the use of the ECN bit in the IPv4 headers. This is a new -feature about Explicit Congestion Notification, but some routers and firewalls -block traffic that has this bit set, so it could be necessary to echo 0 to -/proc/sys/net/ipv4/tcp_ecn if you want to talk to these sites. For more info -you could read RFC2481. - -tcp_retrans_collapse --------------------- - -Bug-to-bug compatibility with some broken printers. On retransmit, try to send -larger packets to work around bugs in certain TCP stacks. Can be turned off by -setting it to zero. - -tcp_keepalive_probes --------------------- - -Number of keep alive probes TCP sends out, until it decides that the -connection is broken. - -tcp_keepalive_time ------------------- - -How often TCP sends out keep alive messages, when keep alive is enabled. The -default is 2 hours. - -tcp_syn_retries ---------------- - -Number of times initial SYNs for a TCP connection attempt will be -retransmitted. Should not be higher than 255. This is only the timeout for -outgoing connections, for incoming connections the number of retransmits is -defined by tcp_retries1. - -tcp_sack --------- - -Enable select acknowledgments after RFC2018. - -tcp_timestamps --------------- - -Enable timestamps as defined in RFC1323. - -tcp_stdurg ----------- - -Enable the strict RFC793 interpretation of the TCP urgent pointer field. The -default is to use the BSD compatible interpretation of the urgent pointer -pointing to the first byte after the urgent data. The RFC793 interpretation is -to have it point to the last byte of urgent data. Enabling this option may -lead to interoperability problems. Disabled by default. - -tcp_syncookies --------------- - -Only valid when the kernel was compiled with CONFIG_SYNCOOKIES. Send out -syncookies when the syn backlog queue of a socket overflows. This is to ward -off the common 'syn flood attack'. Disabled by default. - -Note that the concept of a socket backlog is abandoned. This means the peer -may not receive reliable error messages from an over loaded server with -syncookies enabled. - -tcp_window_scaling ------------------- - -Enable window scaling as defined in RFC1323. - -tcp_fin_timeout ---------------- - -The length of time in seconds it takes to receive a final FIN before the -socket is always closed. This is strictly a violation of the TCP -specification, but required to prevent denial-of-service attacks. - -tcp_max_ka_probes ------------------ - -Indicates how many keep alive probes are sent per slow timer run. Should not -be set too high to prevent bursts. - -tcp_max_syn_backlog -------------------- - -Length of the per socket backlog queue. Since Linux 2.2 the backlog specified -in listen(2) only specifies the length of the backlog queue of already -established sockets. When more connection requests arrive Linux starts to drop -packets. When syncookies are enabled the packets are still answered and the -maximum queue is effectively ignored. - -tcp_retries1 ------------- - -Defines how often an answer to a TCP connection request is retransmitted -before giving up. - -tcp_retries2 ------------- - -Defines how often a TCP packet is retransmitted before giving up. - -Interface specific settings ---------------------------- - -In the directory /proc/sys/net/ipv4/conf you'll find one subdirectory for each -interface the system knows about and one directory calls all. Changes in the -all subdirectory affect all interfaces, whereas changes in the other -subdirectories affect only one interface. All directories have the same -entries: - -accept_redirects ----------------- - -This switch decides if the kernel accepts ICMP redirect messages or not. The -default is 'yes' if the kernel is configured for a regular host and 'no' for a -router configuration. - -accept_source_route -------------------- - -Should source routed packages be accepted or declined. The default is -dependent on the kernel configuration. It's 'yes' for routers and 'no' for -hosts. - -bootp_relay -~~~~~~~~~~~ - -Accept packets with source address 0.b.c.d with destinations not to this host -as local ones. It is supposed that a BOOTP relay daemon will catch and forward -such packets. - -The default is 0, since this feature is not implemented yet (kernel version -2.2.12). - -forwarding ----------- - -Enable or disable IP forwarding on this interface. - -log_martians ------------- - -Log packets with source addresses with no known route to kernel log. - -mc_forwarding -------------- - -Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE and a -multicast routing daemon is required. - -proxy_arp ---------- - -Does (1) or does not (0) perform proxy ARP. - -rp_filter ---------- - -Integer value determines if a source validation should be made. 1 means yes, 0 -means no. Disabled by default, but local/broadcast address spoofing is always -on. - -If you set this to 1 on a router that is the only connection for a network to -the net, it will prevent spoofing attacks against your internal networks -(external addresses can still be spoofed), without the need for additional -firewall rules. - -secure_redirects ----------------- - -Accept ICMP redirect messages only for gateways, listed in default gateway -list. Enabled by default. - -shared_media ------------- - -If it is not set the kernel does not assume that different subnets on this -device can communicate directly. Default setting is 'yes'. - -send_redirects --------------- - -Determines whether to send ICMP redirects to other hosts. - -Routing settings ----------------- - -The directory /proc/sys/net/ipv4/route contains several file to control -routing issues. - -error_burst and error_cost --------------------------- - -These parameters are used to limit how many ICMP destination unreachable to -send from the host in question. ICMP destination unreachable messages are -sent when we cannot reach the next hop while trying to transmit a packet. -It will also print some error messages to kernel logs if someone is ignoring -our ICMP redirects. The higher the error_cost factor is, the fewer -destination unreachable and error messages will be let through. Error_burst -controls when destination unreachable messages and error messages will be -dropped. The default settings limit warning messages to five every second. - -flush ------ - -Writing to this file results in a flush of the routing cache. - -gc_elasticity, gc_interval, gc_min_interval_ms, gc_timeout, gc_thresh ---------------------------------------------------------------------- - -Values to control the frequency and behavior of the garbage collection -algorithm for the routing cache. gc_min_interval is deprecated and replaced -by gc_min_interval_ms. - - -max_size --------- - -Maximum size of the routing cache. Old entries will be purged once the cache -reached has this size. - -redirect_load, redirect_number ------------------------------- - -Factors which determine if more ICPM redirects should be sent to a specific -host. No redirects will be sent once the load limit or the maximum number of -redirects has been reached. - -redirect_silence ----------------- - -Timeout for redirects. After this period redirects will be sent again, even if -this has been stopped, because the load or number limit has been reached. - -Network Neighbor handling -------------------------- - -Settings about how to handle connections with direct neighbors (nodes attached -to the same link) can be found in the directory /proc/sys/net/ipv4/neigh. - -As we saw it in the conf directory, there is a default subdirectory which -holds the default values, and one directory for each interface. The contents -of the directories are identical, with the single exception that the default -settings contain additional options to set garbage collection parameters. - -In the interface directories you'll find the following entries: - -base_reachable_time, base_reachable_time_ms -------------------------------------------- - -A base value used for computing the random reachable time value as specified -in RFC2461. - -Expression of base_reachable_time, which is deprecated, is in seconds. -Expression of base_reachable_time_ms is in milliseconds. - -retrans_time, retrans_time_ms ------------------------------ - -The time between retransmitted Neighbor Solicitation messages. -Used for address resolution and to determine if a neighbor is -unreachable. - -Expression of retrans_time, which is deprecated, is in 1/100 seconds (for -IPv4) or in jiffies (for IPv6). -Expression of retrans_time_ms is in milliseconds. - -unres_qlen ----------- - -Maximum queue length for a pending arp request - the number of packets which -are accepted from other layers while the ARP address is still resolved. - -anycast_delay -------------- - -Maximum for random delay of answers to neighbor solicitation messages in -jiffies (1/100 sec). Not yet implemented (Linux does not have anycast support -yet). - -ucast_solicit -------------- - -Maximum number of retries for unicast solicitation. - -mcast_solicit -------------- - -Maximum number of retries for multicast solicitation. - -delay_first_probe_time ----------------------- - -Delay for the first time probe if the neighbor is reachable. (see -gc_stale_time) - -locktime --------- - -An ARP/neighbor entry is only replaced with a new one if the old is at least -locktime old. This prevents ARP cache thrashing. - -proxy_delay ------------ - -Maximum time (real time is random [0..proxytime]) before answering to an ARP -request for which we have an proxy ARP entry. In some cases, this is used to -prevent network flooding. - -proxy_qlen ----------- - -Maximum queue length of the delayed proxy arp timer. (see proxy_delay). - -app_solicit ----------- - -Determines the number of requests to send to the user level ARP daemon. Use 0 -to turn off. - -gc_stale_time -------------- - -Determines how often to check for stale ARP entries. After an ARP entry is -stale it will be resolved again (which is useful when an IP address migrates -to another machine). When ucast_solicit is greater than 0 it first tries to -send an ARP packet directly to the known host When that fails and -mcast_solicit is greater than 0, an ARP request is broadcasted. - -2.9 Appletalk -------------- - -The /proc/sys/net/appletalk directory holds the Appletalk configuration data -when Appletalk is loaded. The configurable parameters are: - -aarp-expiry-time ----------------- - -The amount of time we keep an ARP entry before expiring it. Used to age out -old hosts. - -aarp-resolve-time ------------------ - -The amount of time we will spend trying to resolve an Appletalk address. - -aarp-retransmit-limit ---------------------- - -The number of times we will retransmit a query before giving up. - -aarp-tick-time --------------- - -Controls the rate at which expires are checked. - -The directory /proc/net/appletalk holds the list of active Appletalk sockets -on a machine. - -The fields indicate the DDP type, the local address (in network:node format) -the remote address, the size of the transmit pending queue, the size of the -received queue (bytes waiting for applications to read) the state and the uid -owning the socket. - -/proc/net/atalk_iface lists all the interfaces configured for appletalk.It -shows the name of the interface, its Appletalk address, the network range on -that address (or network number for phase 1 networks), and the status of the -interface. - -/proc/net/atalk_route lists each known network route. It lists the target -(network) that the route leads to, the router (may be directly connected), the -route flags, and the device the route is using. - -2.10 IPX --------- - -The IPX protocol has no tunable values in proc/sys/net. - -The IPX protocol does, however, provide proc/net/ipx. This lists each IPX -socket giving the local and remote addresses in Novell format (that is -network:node:port). In accordance with the strange Novell tradition, -everything but the port is in hex. Not_Connected is displayed for sockets that -are not tied to a specific remote address. The Tx and Rx queue sizes indicate -the number of bytes pending for transmission and reception. The state -indicates the state the socket is in and the uid is the owning uid of the -socket. - -The /proc/net/ipx_interface file lists all IPX interfaces. For each interface -it gives the network number, the node number, and indicates if the network is -the primary network. It also indicates which device it is bound to (or -Internal for internal networks) and the Frame Type if appropriate. Linux -supports 802.3, 802.2, 802.2 SNAP and DIX (Blue Book) ethernet framing for -IPX. - -The /proc/net/ipx_route table holds a list of IPX routes. For each route it -gives the destination network, the router node (or Directly) and the network -address of the router (or Connected) for internal networks. - -2.11 /proc/sys/fs/mqueue - POSIX message queues filesystem ----------------------------------------------------------- - -The "mqueue" filesystem provides the necessary kernel features to enable the -creation of a user space library that implements the POSIX message queues -API (as noted by the MSG tag in the POSIX 1003.1-2001 version of the System -Interfaces specification.) - -The "mqueue" filesystem contains values for determining/setting the amount of -resources used by the file system. - -/proc/sys/fs/mqueue/queues_max is a read/write file for setting/getting the -maximum number of message queues allowed on the system. - -/proc/sys/fs/mqueue/msg_max is a read/write file for setting/getting the -maximum number of messages in a queue value. In fact it is the limiting value -for another (user) limit which is set in mq_open invocation. This attribute of -a queue must be less or equal then msg_max. - -/proc/sys/fs/mqueue/msgsize_max is a read/write file for setting/getting the -maximum message size value (it is every message queue's attribute set during -its creation). +------------------------------------------------------------------------------ +CHAPTER 3: PER-PROCESS PARAMETERS +------------------------------------------------------------------------------ -2.12 /proc/<pid>/oom_adj - Adjust the oom-killer score +3.1 /proc/<pid>/oom_adj - Adjust the oom-killer score ------------------------------------------------------ This file can be used to adjust the score used to select which processes @@ -2062,25 +1037,15 @@ The task with the highest badness score is then selected and its children are killed, process itself will be killed in an OOM situation when it does not have children or some of them disabled oom like described above. -2.13 /proc/<pid>/oom_score - Display current oom-killer score +3.2 /proc/<pid>/oom_score - Display current oom-killer score ------------------------------------------------------------- ------------------------------------------------------------------------------- This file can be used to check the current score used by the oom-killer is for any given <pid>. Use it together with /proc/<pid>/oom_adj to tune which process should be killed in an out-of-memory situation. ------------------------------------------------------------------------------- -Summary ------------------------------------------------------------------------------- -Certain aspects of kernel behavior can be modified at runtime, without the -need to recompile the kernel, or even to reboot the system. The files in the -/proc/sys tree can not only be read, but also modified. You can use the echo -command to write value into these files, thereby changing the default settings -of the kernel. ------------------------------------------------------------------------------- -2.14 /proc/<pid>/io - Display the IO accounting fields +3.3 /proc/<pid>/io - Display the IO accounting fields ------------------------------------------------------- This file contains IO statistics for each running process @@ -2182,7 +1147,7 @@ those 64-bit counters, process A could see an intermediate result. More information about this can be found within the taskstats documentation in Documentation/accounting. -2.15 /proc/<pid>/coredump_filter - Core dump filtering settings +3.4 /proc/<pid>/coredump_filter - Core dump filtering settings --------------------------------------------------------------- When a process is dumped, all anonymous memory is written to a core file as long as the size of the core file isn't limited. But sometimes we don't want @@ -2226,7 +1191,7 @@ For example: $ echo 0x7 > /proc/self/coredump_filter $ ./some_program -2.16 /proc/<pid>/mountinfo - Information about mounts +3.5 /proc/<pid>/mountinfo - Information about mounts -------------------------------------------------------- This file contains lines of the form: @@ -2263,30 +1228,3 @@ For more information on mount propagation see: Documentation/filesystems/sharedsubtree.txt -2.17 /proc/sys/fs/epoll - Configuration options for the epoll interface --------------------------------------------------------- - -This directory contains configuration options for the epoll(7) interface. - -max_user_instances ------------------- - -This is the maximum number of epoll file descriptors that a single user can -have open at a given time. The default value is 128, and should be enough -for normal users. - -max_user_watches ----------------- - -Every epoll file descriptor can store a number of files to be monitored -for event readiness. Each one of these monitored files constitutes a "watch". -This configuration option sets the maximum number of "watches" that are -allowed for each user. -Each "watch" costs roughly 90 bytes on a 32bit kernel, and roughly 160 bytes -on a 64bit one. -The current default value for max_user_watches is the 1/32 of the available -low memory, divided for the "watch" cost in bytes. - - ------------------------------------------------------------------------------- - diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 9f8740ca3f3..26e4b8bc53e 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -12,6 +12,7 @@ that support it. For example, a given bus might look like this: | |-- enable | |-- irq | |-- local_cpus + | |-- remove | |-- resource | |-- resource0 | |-- resource1 @@ -36,6 +37,7 @@ files, each with their own function. enable Whether the device is enabled (ascii, rw) irq IRQ number (ascii, ro) local_cpus nearby CPU mask (cpumask, ro) + remove remove device from kernel's list (ascii, wo) resource PCI resource host addresses (ascii, ro) resource0..N PCI resource N, if present (binary, mmap) resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap) @@ -46,6 +48,7 @@ files, each with their own function. ro - read only file rw - file is readable and writable + wo - write only file mmap - file is mmapable ascii - file contains ascii text binary - file contains binary data @@ -73,6 +76,13 @@ that the device must be enabled for a rom read to return data succesfully. In the event a driver is not bound to the device, it can be enabled using the 'enable' file, documented above. +The 'remove' file is used to remove the PCI device, by writing a non-zero +integer to the file. This does not involve any kind of hot-plug functionality, +e.g. powering off the device. The device is removed from the kernel's list of +PCI devices, the sysfs directory for it is removed, and the device will be +removed from any drivers attached to it. Removal of PCI root buses is +disallowed. + Accessing legacy resources through sysfs ---------------------------------------- diff --git a/Documentation/filesystems/udf.txt b/Documentation/filesystems/udf.txt index fde829a756e..902b95d0ee5 100644 --- a/Documentation/filesystems/udf.txt +++ b/Documentation/filesystems/udf.txt @@ -24,6 +24,8 @@ The following mount options are supported: gid= Set the default group. umask= Set the default umask. + mode= Set the default file permissions. + dmode= Set the default directory permissions. uid= Set the default user. bs= Set the block size. unhide Show otherwise hidden files. diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt index b1b98870124..145c25a170c 100644 --- a/Documentation/gpio.txt +++ b/Documentation/gpio.txt @@ -123,7 +123,10 @@ platform-specific implementation issue. Using GPIOs ----------- -One of the first things to do with a GPIO, often in board setup code when +The first thing a system should do with a GPIO is allocate it, using +the gpio_request() call; see later. + +One of the next things to do with a GPIO, often in board setup code when setting up a platform_device using the GPIO, is mark its direction: /* set as input or output, returning 0 or negative errno */ @@ -141,8 +144,8 @@ This helps avoid signal glitching during system startup. For compatibility with legacy interfaces to GPIOs, setting the direction of a GPIO implicitly requests that GPIO (see below) if it has not been -requested already. That compatibility may be removed in the future; -explicitly requesting GPIOs is strongly preferred. +requested already. That compatibility is being removed from the optional +gpiolib framework. Setting the direction can fail if the GPIO number is invalid, or when that particular GPIO can't be used in that mode. It's generally a bad @@ -195,7 +198,7 @@ This requires sleeping, which can't be done from inside IRQ handlers. Platforms that support this type of GPIO distinguish them from other GPIOs by returning nonzero from this call (which requires a valid GPIO number, -either explicitly or implicitly requested): +which should have been previously allocated with gpio_request): int gpio_cansleep(unsigned gpio); @@ -212,10 +215,9 @@ for GPIOs that can't be accessed from IRQ handlers, these calls act the same as the spinlock-safe calls. -Claiming and Releasing GPIOs (OPTIONAL) ---------------------------------------- +Claiming and Releasing GPIOs +---------------------------- To help catch system configuration errors, two calls are defined. -However, many platforms don't currently support this mechanism. /* request GPIO, returning 0 or negative errno. * non-null labels may be useful for diagnostics. @@ -244,13 +246,6 @@ Some platforms may also use knowledge about what GPIOs are active for power management, such as by powering down unused chip sectors and, more easily, gating off unused clocks. -These two calls are optional because not not all current Linux platforms -offer such functionality in their GPIO support; a valid implementation -could return success for all gpio_request() calls. Unlike the other calls, -the state they represent doesn't normally match anything from a hardware -register; it's just a software bitmap which clearly is not necessary for -correct operation of hardware or (bug free) drivers. - Note that requesting a GPIO does NOT cause it to be configured in any way; it just marks that GPIO as in use. Separate code must handle any pin setup (e.g. controlling which pin the GPIO uses, pullup/pulldown). diff --git a/Documentation/hwmon/lis3lv02d b/Documentation/hwmon/lis3lv02d index 287f8c90265..effe949a728 100644 --- a/Documentation/hwmon/lis3lv02d +++ b/Documentation/hwmon/lis3lv02d @@ -1,11 +1,11 @@ Kernel driver lis3lv02d -================== +======================= Supported chips: * STMicroelectronics LIS3LV02DL and LIS3LV02DQ -Author: +Authors: Yan Burman <burman.yan@gmail.com> Eric Piel <eric.piel@tremplin-utc.net> @@ -15,7 +15,7 @@ Description This driver provides support for the accelerometer found in various HP laptops sporting the feature officially called "HP Mobile Data -Protection System 3D" or "HP 3D DriveGuard". It detect automatically +Protection System 3D" or "HP 3D DriveGuard". It detects automatically laptops with this sensor. Known models (for now the HP 2133, nc6420, nc2510, nc8510, nc84x0, nw9440 and nx9420) will have their axis automatically oriented on standard way (eg: you can directly play @@ -27,7 +27,7 @@ position - 3D position that the accelerometer reports. Format: "(x,y,z)" calibrate - read: values (x, y, z) that are used as the base for input class device operation. write: forces the base to be recalibrated with the current - position. + position. rate - reports the sampling rate of the accelerometer device in HZ This driver also provides an absolute input class device, allowing @@ -48,7 +48,7 @@ For better compatibility between the various laptops. The values reported by the accelerometer are converted into a "standard" organisation of the axes (aka "can play neverball out of the box"): * When the laptop is horizontal the position reported is about 0 for X and Y -and a positive value for Z + and a positive value for Z * If the left side is elevated, X increases (becomes positive) * If the front side (where the touchpad is) is elevated, Y decreases (becomes negative) @@ -59,3 +59,13 @@ email to the authors to add it to the database. When reporting a new laptop, please include the output of "dmidecode" plus the value of /sys/devices/platform/lis3lv02d/position in these four cases. +Q&A +--- + +Q: How do I safely simulate freefall? I have an HP "portable +workstation" which has about 3.5kg and a plastic case, so letting it +fall to the ground is out of question... + +A: The sensor is pretty sensitive, so your hands can do it. Lift it +into free space, follow the fall with your hands for like 10 +centimeters. That should be enough to trigger the detection. diff --git a/Documentation/hwmon/ltc4215 b/Documentation/hwmon/ltc4215 new file mode 100644 index 00000000000..2e6a21eb656 --- /dev/null +++ b/Documentation/hwmon/ltc4215 @@ -0,0 +1,50 @@ +Kernel driver ltc4215 +===================== + +Supported chips: + * Linear Technology LTC4215 + Prefix: 'ltc4215' + Addresses scanned: 0x44 + Datasheet: + http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1163,P17572,D12697 + +Author: Ira W. Snyder <iws@ovro.caltech.edu> + + +Description +----------- + +The LTC4215 controller allows a board to be safely inserted and removed +from a live backplane. + + +Usage Notes +----------- + +This driver does not probe for LTC4215 devices, due to the fact that some +of the possible addresses are unfriendly to probing. You will need to use +the "force" parameter to tell the driver where to find the device. + +Example: the following will load the driver for an LTC4215 at address 0x44 +on I2C bus #0: +$ modprobe ltc4215 force=0,0x44 + + +Sysfs entries +------------- + +The LTC4215 has built-in limits for overvoltage, undervoltage, and +undercurrent warnings. This makes it very likely that the reference +circuit will be used. + +in1_input input voltage +in2_input output voltage + +in1_min_alarm input undervoltage alarm +in1_max_alarm input overvoltage alarm + +curr1_input current +curr1_max_alarm overcurrent alarm + +power1_input power usage +power1_alarm power bad alarm diff --git a/Documentation/ia64/kvm.txt b/Documentation/ia64/kvm.txt index 84f7cb3d5be..ffb5c80bec3 100644 --- a/Documentation/ia64/kvm.txt +++ b/Documentation/ia64/kvm.txt @@ -42,7 +42,7 @@ Note: For step 2, please make sure that host page size == TARGET_PAGE_SIZE of qe hg clone http://xenbits.xensource.com/ext/efi-vfirmware.hg you can get the firmware's binary in the directory of efi-vfirmware.hg/binaries. - (3) Rename the firware you owned to Flash.fd, and copy it to /usr/local/share/qemu + (3) Rename the firmware you owned to Flash.fd, and copy it to /usr/local/share/qemu 4. Boot up Linux or Windows guests: 4.1 Create or install a image for guest boot. If you have xen experience, it should be easy. diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index aeedb89a307..0b7351b0582 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -617,6 +617,9 @@ and is between 256 and 4096 characters. It is defined in the file debug_objects [KNL] Enable object debugging + no_debug_objects + [KNL] Disable object debugging + debugpat [X86] Enable PAT debugging decnet.addr= [HW,NET] @@ -1523,7 +1526,9 @@ and is between 256 and 4096 characters. It is defined in the file noclflush [BUGS=X86] Don't use the CLFLUSH instruction - nohlt [BUGS=ARM,SH] + nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or + wfi(ARM) instruction doesn't work correctly and not to + use it. This is also useful when using JTAG debugger. no-hlt [BUGS=X86-32] Tells the kernel that the hlt instruction doesn't work correctly and not to @@ -1603,7 +1608,7 @@ and is between 256 and 4096 characters. It is defined in the file nosoftlockup [KNL] Disable the soft-lockup detector. noswapaccount [KNL] Disable accounting of swap in memory resource - controller. (See Documentation/controllers/memory.txt) + controller. (See Documentation/cgroups/memory.txt) nosync [HW,M68K] Disables sync negotiation for all devices. @@ -1695,6 +1700,8 @@ and is between 256 and 4096 characters. It is defined in the file See also Documentation/blockdev/paride.txt. pci=option[,option...] [PCI] various PCI subsystem options: + earlydump [X86] dump PCI config space before the kernel + changes anything off [X86] don't probe for the PCI bus bios [X86-32] force use of PCI BIOS, don't access the hardware directly. Use this if your machine @@ -1794,6 +1801,15 @@ and is between 256 and 4096 characters. It is defined in the file cbmemsize=nn[KMG] The fixed amount of bus space which is reserved for the CardBus bridge's memory window. The default value is 64 megabytes. + resource_alignment= + Format: + [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...] + Specifies alignment and device to reassign + aligned memory resources. + If <order of align> is not specified, + PAGE_SIZE is used as alignment. + PCI-PCI bridge can be specified, if resource + windows need to be expanded. pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power Management. @@ -1942,7 +1958,7 @@ and is between 256 and 4096 characters. It is defined in the file relax_domain_level= [KNL, SMP] Set scheduler's default relax_domain_level. - See Documentation/cpusets.txt. + See Documentation/cgroups/cpusets.txt. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area diff --git a/Documentation/md.txt b/Documentation/md.txt index 1da9d1b1793..4edd39ec7db 100644 --- a/Documentation/md.txt +++ b/Documentation/md.txt @@ -164,15 +164,19 @@ All md devices contain: raid_disks a text file with a simple number indicating the number of devices in a fully functional array. If this is not yet known, the file - will be empty. If an array is being resized (not currently - possible) this will contain the larger of the old and new sizes. - Some raid level (RAID1) allow this value to be set while the - array is active. This will reconfigure the array. Otherwise - it can only be set while assembling an array. + will be empty. If an array is being resized this will contain + the new number of devices. + Some raid levels allow this value to be set while the array is + active. This will reconfigure the array. Otherwise it can only + be set while assembling an array. + A change to this attribute will not be permitted if it would + reduce the size of the array. To reduce the number of drives + in an e.g. raid5, the array size must first be reduced by + setting the 'array_size' attribute. chunk_size - This is the size if bytes for 'chunks' and is only relevant to - raid levels that involve striping (1,4,5,6,10). The address space + This is the size in bytes for 'chunks' and is only relevant to + raid levels that involve striping (0,4,5,6,10). The address space of the array is conceptually divided into chunks and consecutive chunks are striped onto neighbouring devices. The size should be at least PAGE_SIZE (4k) and should be a power @@ -183,6 +187,20 @@ All md devices contain: simply a number that is interpretted differently by different levels. It can be written while assembling an array. + array_size + This can be used to artificially constrain the available space in + the array to be less than is actually available on the combined + devices. Writing a number (in Kilobytes) which is less than + the available size will set the size. Any reconfiguration of the + array (e.g. adding devices) will not cause the size to change. + Writing the word 'default' will cause the effective size of the + array to be whatever size is actually available based on + 'level', 'chunk_size' and 'component_size'. + + This can be used to reduce the size of the array before reducing + the number of devices in a raid4/5/6, or to support external + metadata formats which mandate such clipping. + reshape_position This is either "none" or a sector number within the devices of the array where "reshape" is up to. If this is set, the three @@ -207,6 +225,11 @@ All md devices contain: about the array. It can be 0.90 (traditional format), 1.0, 1.1, 1.2 (newer format in varying locations) or "none" indicating that the kernel isn't managing metadata at all. + Alternately it can be "external:" followed by a string which + is set by user-space. This indicates that metadata is managed + by a user-space program. Any device failure or other event that + requires a metadata update will cause array activity to be + suspended until the event is acknowledged. resync_start The point at which resync should start. If no resync is needed, diff --git a/Documentation/misc-devices/isl29003 b/Documentation/misc-devices/isl29003 new file mode 100644 index 00000000000..c4ff5f38e01 --- /dev/null +++ b/Documentation/misc-devices/isl29003 @@ -0,0 +1,62 @@ +Kernel driver isl29003 +===================== + +Supported chips: +* Intersil ISL29003 +Prefix: 'isl29003' +Addresses scanned: none +Datasheet: +http://www.intersil.com/data/fn/fn7464.pdf + +Author: Daniel Mack <daniel@caiaq.de> + + +Description +----------- +The ISL29003 is an integrated light sensor with a 16-bit integrating type +ADC, I2C user programmable lux range select for optimized counts/lux, and +I2C multi-function control and monitoring capabilities. The internal ADC +provides 16-bit resolution while rejecting 50Hz and 60Hz flicker caused by +artificial light sources. + +The driver allows to set the lux range, the bit resolution, the operational +mode (see below) and the power state of device and can read the current lux +value, of course. + + +Detection +--------- + +The ISL29003 does not have an ID register which could be used to identify +it, so the detection routine will just try to read from the configured I2C +addess and consider the device to be present as soon as it ACKs the +transfer. + + +Sysfs entries +------------- + +range: + 0: 0 lux to 1000 lux (default) + 1: 0 lux to 4000 lux + 2: 0 lux to 16,000 lux + 3: 0 lux to 64,000 lux + +resolution: + 0: 2^16 cycles (default) + 1: 2^12 cycles + 2: 2^8 cycles + 3: 2^4 cycles + +mode: + 0: diode1's current (unsigned 16bit) (default) + 1: diode1's current (unsigned 16bit) + 2: difference between diodes (l1 - l2, signed 15bit) + +power_state: + 0: device is disabled (default) + 1: device is enabled + +lux (read only): + returns the value from the last sensor reading + diff --git a/Documentation/networking/vxge.txt b/Documentation/networking/vxge.txt new file mode 100644 index 00000000000..d2e2997e6fa --- /dev/null +++ b/Documentation/networking/vxge.txt @@ -0,0 +1,100 @@ +Neterion's (Formerly S2io) X3100 Series 10GbE PCIe Server Adapter Linux driver +============================================================================== + +Contents +-------- + +1) Introduction +2) Features supported +3) Configurable driver parameters +4) Troubleshooting + +1) Introduction: +---------------- +This Linux driver supports all Neterion's X3100 series 10 GbE PCIe I/O +Virtualized Server adapters. +The X3100 series supports four modes of operation, configurable via +firmware - + Single function mode + Multi function mode + SRIOV mode + MRIOV mode +The functions share a 10GbE link and the pci-e bus, but hardly anything else +inside the ASIC. Features like independent hw reset, statistics, bandwidth/ +priority allocation and guarantees, GRO, TSO, interrupt moderation etc are +supported independently on each function. + +(See below for a complete list of features supported for both IPv4 and IPv6) + +2) Features supported: +---------------------- + +i) Single function mode (up to 17 queues) + +ii) Multi function mode (up to 17 functions) + +iii) PCI-SIG's I/O Virtualization + - Single Root mode: v1.0 (up to 17 functions) + - Multi-Root mode: v1.0 (up to 17 functions) + +iv) Jumbo frames + X3100 Series supports MTU up to 9600 bytes, modifiable using + ifconfig command. + +v) Offloads supported: (Enabled by default) + Checksum offload (TCP/UDP/IP) on transmit and receive paths + TCP Segmentation Offload (TSO) on transmit path + Generic Receive Offload (GRO) on receive path + +vi) MSI-X: (Enabled by default) + Resulting in noticeable performance improvement (up to 7% on certain + platforms). + +vii) NAPI: (Enabled by default) + For better Rx interrupt moderation. + +viii)RTH (Receive Traffic Hash): (Enabled by default) + Receive side steering for better scaling. + +ix) Statistics + Comprehensive MAC-level and software statistics displayed using + "ethtool -S" option. + +x) Multiple hardware queues: (Enabled by default) + Up to 17 hardware based transmit and receive data channels, with + multiple steering options (transmit multiqueue enabled by default). + +3) Configurable driver parameters: +---------------------------------- + +i) max_config_dev + Specifies maximum device functions to be enabled. + Valid range: 1-8 + +ii) max_config_port + Specifies number of ports to be enabled. + Valid range: 1,2 + Default: 1 + +iii)max_config_vpath + Specifies maximum VPATH(s) configured for each device function. + Valid range: 1-17 + +iv) vlan_tag_strip + Enables/disables vlan tag stripping from all received tagged frames that + are not replicated at the internal L2 switch. + Valid range: 0,1 (disabled, enabled respectively) + Default: 1 + +v) addr_learn_en + Enable learning the mac address of the guest OS interface in + virtualization environment. + Valid range: 0,1 (disabled, enabled respectively) + Default: 0 + +4) Troubleshooting: +------------------- + +To resolve an issue with the source code or X3100 series adapter, please collect +the statistics, register dumps using ethool, relevant logs and email them to +support@neterion.com. diff --git a/Documentation/powerpc/dts-bindings/fsl/cpm_qe/qe/firmware.txt b/Documentation/powerpc/dts-bindings/fsl/cpm_qe/qe/firmware.txt index 6c238f59b2a..249db3a15d1 100644 --- a/Documentation/powerpc/dts-bindings/fsl/cpm_qe/qe/firmware.txt +++ b/Documentation/powerpc/dts-bindings/fsl/cpm_qe/qe/firmware.txt @@ -1,6 +1,6 @@ * Uploaded QE firmware - If a new firwmare has been uploaded to the QE (usually by the + If a new firmware has been uploaded to the QE (usually by the boot loader), then a 'firmware' child node should be added to the QE node. This node provides information on the uploaded firmware that device drivers may need. diff --git a/Documentation/powerpc/dts-bindings/mmc-spi-slot.txt b/Documentation/powerpc/dts-bindings/mmc-spi-slot.txt new file mode 100644 index 00000000000..c39ac289195 --- /dev/null +++ b/Documentation/powerpc/dts-bindings/mmc-spi-slot.txt @@ -0,0 +1,23 @@ +MMC/SD/SDIO slot directly connected to a SPI bus + +Required properties: +- compatible : should be "mmc-spi-slot". +- reg : should specify SPI address (chip-select number). +- spi-max-frequency : maximum frequency for this device (Hz). +- voltage-ranges : two cells are required, first cell specifies minimum + slot voltage (mV), second cell specifies maximum slot voltage (mV). + Several ranges could be specified. +- gpios : (optional) may specify GPIOs in this order: Card-Detect GPIO, + Write-Protect GPIO. + +Example: + + mmc-slot@0 { + compatible = "fsl,mpc8323rdb-mmc-slot", + "mmc-spi-slot"; + reg = <0>; + gpios = <&qe_pio_d 14 1 + &qe_pio_d 15 0>; + voltage-ranges = <3300 3300>; + spi-max-frequency = <50000000>; + }; diff --git a/Documentation/scheduler/sched-rt-group.txt b/Documentation/scheduler/sched-rt-group.txt index 3ef339f491e..5ba4d3fc625 100644 --- a/Documentation/scheduler/sched-rt-group.txt +++ b/Documentation/scheduler/sched-rt-group.txt @@ -126,7 +126,7 @@ This uses the /cgroup virtual file system and "/cgroup/<cgroup>/cpu.rt_runtime_u to control the CPU time reserved for each control group instead. For more information on working with control groups, you should read -Documentation/cgroups.txt as well. +Documentation/cgroups/cgroups.txt as well. Group settings are checked against the following limits in order to keep the configuration schedulable: diff --git a/Documentation/slow-work.txt b/Documentation/slow-work.txt new file mode 100644 index 00000000000..ebc50f808ea --- /dev/null +++ b/Documentation/slow-work.txt @@ -0,0 +1,174 @@ + ==================================== + SLOW WORK ITEM EXECUTION THREAD POOL + ==================================== + +By: David Howells <dhowells@redhat.com> + +The slow work item execution thread pool is a pool of threads for performing +things that take a relatively long time, such as making mkdir calls. +Typically, when processing something, these items will spend a lot of time +blocking a thread on I/O, thus making that thread unavailable for doing other +work. + +The standard workqueue model is unsuitable for this class of work item as that +limits the owner to a single thread or a single thread per CPU. For some +tasks, however, more threads - or fewer - are required. + +There is just one pool per system. It contains no threads unless something +wants to use it - and that something must register its interest first. When +the pool is active, the number of threads it contains is dynamic, varying +between a maximum and minimum setting, depending on the load. + + +==================== +CLASSES OF WORK ITEM +==================== + +This pool support two classes of work items: + + (*) Slow work items. + + (*) Very slow work items. + +The former are expected to finish much quicker than the latter. + +An operation of the very slow class may do a batch combination of several +lookups, mkdirs, and a create for instance. + +An operation of the ordinarily slow class may, for example, write stuff or +expand files, provided the time taken to do so isn't too long. + +Operations of both types may sleep during execution, thus tying up the thread +loaned to it. + + +THREAD-TO-CLASS ALLOCATION +-------------------------- + +Not all the threads in the pool are available to work on very slow work items. +The number will be between one and one fewer than the number of active threads. +This is configurable (see the "Pool Configuration" section). + +All the threads are available to work on ordinarily slow work items, but a +percentage of the threads will prefer to work on very slow work items. + +The configuration ensures that at least one thread will be available to work on +very slow work items, and at least one thread will be available that won't work +on very slow work items at all. + + +===================== +USING SLOW WORK ITEMS +===================== + +Firstly, a module or subsystem wanting to make use of slow work items must +register its interest: + + int ret = slow_work_register_user(); + +This will return 0 if successful, or a -ve error upon failure. + + +Slow work items may then be set up by: + + (1) Declaring a slow_work struct type variable: + + #include <linux/slow-work.h> + + struct slow_work myitem; + + (2) Declaring the operations to be used for this item: + + struct slow_work_ops myitem_ops = { + .get_ref = myitem_get_ref, + .put_ref = myitem_put_ref, + .execute = myitem_execute, + }; + + [*] For a description of the ops, see section "Item Operations". + + (3) Initialising the item: + + slow_work_init(&myitem, &myitem_ops); + + or: + + vslow_work_init(&myitem, &myitem_ops); + + depending on its class. + +A suitably set up work item can then be enqueued for processing: + + int ret = slow_work_enqueue(&myitem); + +This will return a -ve error if the thread pool is unable to gain a reference +on the item, 0 otherwise. + + +The items are reference counted, so there ought to be no need for a flush +operation. When all a module's slow work items have been processed, and the +module has no further interest in the facility, it should unregister its +interest: + + slow_work_unregister_user(); + + +=============== +ITEM OPERATIONS +=============== + +Each work item requires a table of operations of type struct slow_work_ops. +All members are required: + + (*) Get a reference on an item: + + int (*get_ref)(struct slow_work *work); + + This allows the thread pool to attempt to pin an item by getting a + reference on it. This function should return 0 if the reference was + granted, or a -ve error otherwise. If an error is returned, + slow_work_enqueue() will fail. + + The reference is held whilst the item is queued and whilst it is being + executed. The item may then be requeued with the same reference held, or + the reference will be released. + + (*) Release a reference on an item: + + void (*put_ref)(struct slow_work *work); + + This allows the thread pool to unpin an item by releasing the reference on + it. The thread pool will not touch the item again once this has been + called. + + (*) Execute an item: + + void (*execute)(struct slow_work *work); + + This should perform the work required of the item. It may sleep, it may + perform disk I/O and it may wait for locks. + + +================== +POOL CONFIGURATION +================== + +The slow-work thread pool has a number of configurables: + + (*) /proc/sys/kernel/slow-work/min-threads + + The minimum number of threads that should be in the pool whilst it is in + use. This may be anywhere between 2 and max-threads. + + (*) /proc/sys/kernel/slow-work/max-threads + + The maximum number of threads that should in the pool. This may be + anywhere between min-threads and 255 or NR_CPUS * 2, whichever is greater. + + (*) /proc/sys/kernel/slow-work/vslow-percentage + + The percentage of active threads in the pool that may be used to execute + very slow work items. This may be between 1 and 99. The resultant number + is bounded to between 1 and one fewer than the number of active threads. + This ensures there is always at least one thread that can process very + slow work items, and always at least one thread that won't. diff --git a/Documentation/sysctl/00-INDEX b/Documentation/sysctl/00-INDEX index a20a9066dc4..1286f455992 100644 --- a/Documentation/sysctl/00-INDEX +++ b/Documentation/sysctl/00-INDEX @@ -10,6 +10,8 @@ fs.txt - documentation for /proc/sys/fs/*. kernel.txt - documentation for /proc/sys/kernel/*. +net.txt + - documentation for /proc/sys/net/*. sunrpc.txt - documentation for /proc/sys/sunrpc/*. vm.txt diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt index f99254327ae..1458448436c 100644 --- a/Documentation/sysctl/fs.txt +++ b/Documentation/sysctl/fs.txt @@ -1,5 +1,6 @@ Documentation for /proc/sys/fs/* kernel version 2.2.10 (c) 1998, 1999, Rik van Riel <riel@nl.linux.org> + (c) 2009, Shen Feng<shen@cn.fujitsu.com> For general info and legal blurb, please look in README. @@ -14,7 +15,12 @@ kernel. Since some of the files _can_ be used to screw up your system, it is advisable to read both documentation and source before actually making adjustments. +1. /proc/sys/fs +---------------------------------------------------------- + Currently, these files are in /proc/sys/fs: +- aio-max-nr +- aio-nr - dentry-state - dquot-max - dquot-nr @@ -30,8 +36,15 @@ Currently, these files are in /proc/sys/fs: - super-max - super-nr -Documentation for the files in /proc/sys/fs/binfmt_misc is -in Documentation/binfmt_misc.txt. +============================================================== + +aio-nr & aio-max-nr: + +aio-nr is the running total of the number of events specified on the +io_setup system call for all currently active aio contexts. If aio-nr +reaches aio-max-nr then io_setup will fail with EAGAIN. Note that +raising aio-max-nr does not result in the pre-allocation or re-sizing +of any kernel data structures. ============================================================== @@ -178,3 +191,60 @@ requests. aio-max-nr allows you to change the maximum value aio-nr can grow to. ============================================================== + + +2. /proc/sys/fs/binfmt_misc +---------------------------------------------------------- + +Documentation for the files in /proc/sys/fs/binfmt_misc is +in Documentation/binfmt_misc.txt. + + +3. /proc/sys/fs/mqueue - POSIX message queues filesystem +---------------------------------------------------------- + +The "mqueue" filesystem provides the necessary kernel features to enable the +creation of a user space library that implements the POSIX message queues +API (as noted by the MSG tag in the POSIX 1003.1-2001 version of the System +Interfaces specification.) + +The "mqueue" filesystem contains values for determining/setting the amount of +resources used by the file system. + +/proc/sys/fs/mqueue/queues_max is a read/write file for setting/getting the +maximum number of message queues allowed on the system. + +/proc/sys/fs/mqueue/msg_max is a read/write file for setting/getting the +maximum number of messages in a queue value. In fact it is the limiting value +for another (user) limit which is set in mq_open invocation. This attribute of +a queue must be less or equal then msg_max. + +/proc/sys/fs/mqueue/msgsize_max is a read/write file for setting/getting the +maximum message size value (it is every message queue's attribute set during +its creation). + + +4. /proc/sys/fs/epoll - Configuration options for the epoll interface +-------------------------------------------------------- + +This directory contains configuration options for the epoll(7) interface. + +max_user_instances +------------------ + +This is the maximum number of epoll file descriptors that a single user can +have open at a given time. The default value is 128, and should be enough +for normal users. + +max_user_watches +---------------- + +Every epoll file descriptor can store a number of files to be monitored +for event readiness. Each one of these monitored files constitutes a "watch". +This configuration option sets the maximum number of "watches" that are +allowed for each user. +Each "watch" costs roughly 90 bytes on a 32bit kernel, and roughly 160 bytes +on a 64bit one. +The current default value for max_user_watches is the 1/32 of the available +low memory, divided for the "watch" cost in bytes. + diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index a4ccdd1981c..f11ca7979fa 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -1,5 +1,6 @@ Documentation for /proc/sys/kernel/* kernel version 2.2.10 (c) 1998, 1999, Rik van Riel <riel@nl.linux.org> + (c) 2009, Shen Feng<shen@cn.fujitsu.com> For general info and legal blurb, please look in README. @@ -18,6 +19,7 @@ Currently, these files might (depending on your configuration) show up in /proc/sys/kernel: - acpi_video_flags - acct +- auto_msgmni - core_pattern - core_uses_pid - ctrl-alt-del @@ -33,6 +35,7 @@ show up in /proc/sys/kernel: - msgmax - msgmnb - msgmni +- nmi_watchdog - osrelease - ostype - overflowgid @@ -40,6 +43,7 @@ show up in /proc/sys/kernel: - panic - pid_max - powersave-nap [ PPC only ] +- panic_on_unrecovered_nmi - printk - randomize_va_space - real-root-dev ==> Documentation/initrd.txt @@ -55,6 +59,7 @@ show up in /proc/sys/kernel: - sysrq ==> Documentation/sysrq.txt - tainted - threads-max +- unknown_nmi_panic - version ============================================================== @@ -381,3 +386,51 @@ can be ORed together: 512 - A kernel warning has occurred. 1024 - A module from drivers/staging was loaded. +============================================================== + +auto_msgmni: + +Enables/Disables automatic recomputing of msgmni upon memory add/remove or +upon ipc namespace creation/removal (see the msgmni description above). +Echoing "1" into this file enables msgmni automatic recomputing. +Echoing "0" turns it off. +auto_msgmni default value is 1. + +============================================================== + +nmi_watchdog: + +Enables/Disables the NMI watchdog on x86 systems. When the value is non-zero +the NMI watchdog is enabled and will continuously test all online cpus to +determine whether or not they are still functioning properly. Currently, +passing "nmi_watchdog=" parameter at boot time is required for this function +to work. + +If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel parameter), the +NMI watchdog shares registers with oprofile. By disabling the NMI watchdog, +oprofile may have more registers to utilize. + +============================================================== + +unknown_nmi_panic: + +The value in this file affects behavior of handling NMI. When the value is +non-zero, unknown NMI is trapped and then panic occurs. At that time, kernel +debugging information is displayed on console. + +NMI switch that most IA32 servers have fires unknown NMI up, for example. +If a system hangs up, try pressing the NMI switch. + +============================================================== + +panic_on_unrecovered_nmi: + +The default Linux behaviour on an NMI of either memory or unknown is to continue +operation. For many environments such as scientific computing it is preferable +that the box is taken out and the error dealt with than an uncorrected +parity/ECC error get propogated. + +A small number of systems do generate NMI's for bizarre random reasons such as +power management so the default is off. That sysctl works like the existing +panic controls already in that directory. + diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt new file mode 100644 index 00000000000..a34d55b6544 --- /dev/null +++ b/Documentation/sysctl/net.txt @@ -0,0 +1,175 @@ +Documentation for /proc/sys/net/* kernel version 2.4.0-test11-pre4 + (c) 1999 Terrehon Bowden <terrehon@pacbell.net> + Bodo Bauer <bb@ricochet.net> + (c) 2000 Jorge Nerin <comandante@zaralinux.com> + (c) 2009 Shen Feng <shen@cn.fujitsu.com> + +For general info and legal blurb, please look in README. + +============================================================== + +This file contains the documentation for the sysctl files in +/proc/sys/net and is valid for Linux kernel version 2.4.0-test11-pre4. + +The interface to the networking parts of the kernel is located in +/proc/sys/net. The following table shows all possible subdirectories.You may +see only some of them, depending on your kernel's configuration. + + +Table : Subdirectories in /proc/sys/net +.............................................................................. + Directory Content Directory Content + core General parameter appletalk Appletalk protocol + unix Unix domain sockets netrom NET/ROM + 802 E802 protocol ax25 AX25 + ethernet Ethernet protocol rose X.25 PLP layer + ipv4 IP version 4 x25 X.25 protocol + ipx IPX token-ring IBM token ring + bridge Bridging decnet DEC net + ipv6 IP version 6 +.............................................................................. + +1. /proc/sys/net/core - Network core options +------------------------------------------------------- + +rmem_default +------------ + +The default setting of the socket receive buffer in bytes. + +rmem_max +-------- + +The maximum receive socket buffer size in bytes. + +wmem_default +------------ + +The default setting (in bytes) of the socket send buffer. + +wmem_max +-------- + +The maximum send socket buffer size in bytes. + +message_burst and message_cost +------------------------------ + +These parameters are used to limit the warning messages written to the kernel +log from the networking code. They enforce a rate limit to make a +denial-of-service attack impossible. A higher message_cost factor, results in +fewer messages that will be written. Message_burst controls when messages will +be dropped. The default settings limit warning messages to one every five +seconds. + +warnings +-------- + +This controls console messages from the networking stack that can occur because +of problems on the network like duplicate address or bad checksums. Normally, +this should be enabled, but if the problem persists the messages can be +disabled. + +netdev_budget +------------- + +Maximum number of packets taken from all interfaces in one polling cycle (NAPI +poll). In one polling cycle interfaces which are registered to polling are +probed in a round-robin manner. The limit of packets in one such probe can be +set per-device via sysfs class/net/<device>/weight . + +netdev_max_backlog +------------------ + +Maximum number of packets, queued on the INPUT side, when the interface +receives packets faster than kernel can process them. + +optmem_max +---------- + +Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence +of struct cmsghdr structures with appended data. + +2. /proc/sys/net/unix - Parameters for Unix domain sockets +------------------------------------------------------- + +There is only one file in this directory. +unix_dgram_qlen limits the max number of datagrams queued in Unix domain +socket's buffer. It will not take effect unless PF_UNIX flag is spicified. + + +3. /proc/sys/net/ipv4 - IPV4 settings +------------------------------------------------------- +Please see: Documentation/networking/ip-sysctl.txt and ipvs-sysctl.txt for +descriptions of these entries. + + +4. Appletalk +------------------------------------------------------- + +The /proc/sys/net/appletalk directory holds the Appletalk configuration data +when Appletalk is loaded. The configurable parameters are: + +aarp-expiry-time +---------------- + +The amount of time we keep an ARP entry before expiring it. Used to age out +old hosts. + +aarp-resolve-time +----------------- + +The amount of time we will spend trying to resolve an Appletalk address. + +aarp-retransmit-limit +--------------------- + +The number of times we will retransmit a query before giving up. + +aarp-tick-time +-------------- + +Controls the rate at which expires are checked. + +The directory /proc/net/appletalk holds the list of active Appletalk sockets +on a machine. + +The fields indicate the DDP type, the local address (in network:node format) +the remote address, the size of the transmit pending queue, the size of the +received queue (bytes waiting for applications to read) the state and the uid +owning the socket. + +/proc/net/atalk_iface lists all the interfaces configured for appletalk.It +shows the name of the interface, its Appletalk address, the network range on +that address (or network number for phase 1 networks), and the status of the +interface. + +/proc/net/atalk_route lists each known network route. It lists the target +(network) that the route leads to, the router (may be directly connected), the +route flags, and the device the route is using. + + +5. IPX +------------------------------------------------------- + +The IPX protocol has no tunable values in proc/sys/net. + +The IPX protocol does, however, provide proc/net/ipx. This lists each IPX +socket giving the local and remote addresses in Novell format (that is +network:node:port). In accordance with the strange Novell tradition, +everything but the port is in hex. Not_Connected is displayed for sockets that +are not tied to a specific remote address. The Tx and Rx queue sizes indicate +the number of bytes pending for transmission and reception. The state +indicates the state the socket is in and the uid is the owning uid of the +socket. + +The /proc/net/ipx_interface file lists all IPX interfaces. For each interface +it gives the network number, the node number, and indicates if the network is +the primary network. It also indicates which device it is bound to (or +Internal for internal networks) and the Frame Type if appropriate. Linux +supports 802.3, 802.2, 802.2 SNAP and DIX (Blue Book) ethernet framing for +IPX. + +The /proc/net/ipx_route table holds a list of IPX routes. For each route it +gives the destination network, the router node (or Directly) and the network +address of the router (or Connected) for internal networks. diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt index 9e592c718af..afa2946892d 100644 --- a/Documentation/sysrq.txt +++ b/Documentation/sysrq.txt @@ -81,6 +81,8 @@ On all - write a character to /proc/sysrq-trigger. e.g.: 'i' - Send a SIGKILL to all processes, except for init. +'j' - Forcibly "Just thaw it" - filesystems frozen by the FIFREEZE ioctl. + 'k' - Secure Access Key (SAK) Kills all programs on the current virtual console. NOTE: See important comments below in SAK section. @@ -160,6 +162,9 @@ t'E'rm and k'I'll are useful if you have some sort of runaway process you are unable to kill any other way, especially if it's spawning other processes. +"'J'ust thaw it" is useful if your system becomes unresponsive due to a frozen +(probably root) filesystem via the FIFREEZE ioctl. + * Sometimes SysRq seems to get 'stuck' after using it, what can I do? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ That happens to me, also. I've found that tapping shift, alt, and control diff --git a/Documentation/vm/numa_memory_policy.txt b/Documentation/vm/numa_memory_policy.txt index 6aaaeb38730..be45dbb9d7f 100644 --- a/Documentation/vm/numa_memory_policy.txt +++ b/Documentation/vm/numa_memory_policy.txt @@ -8,7 +8,8 @@ The current memory policy support was added to Linux 2.6 around May 2004. This document attempts to describe the concepts and APIs of the 2.6 memory policy support. -Memory policies should not be confused with cpusets (Documentation/cpusets.txt) +Memory policies should not be confused with cpusets +(Documentation/cgroups/cpusets.txt) which is an administrative mechanism for restricting the nodes from which memory may be allocated by a set of processes. Memory policies are a programming interface that a NUMA-aware application can take advantage of. When diff --git a/Documentation/vm/page_migration b/Documentation/vm/page_migration index d5fdfd34bba..6513fe2d90b 100644 --- a/Documentation/vm/page_migration +++ b/Documentation/vm/page_migration @@ -37,7 +37,8 @@ locations. Larger installations usually partition the system using cpusets into sections of nodes. Paul Jackson has equipped cpusets with the ability to -move pages when a task is moved to another cpuset (See ../cpusets.txt). +move pages when a task is moved to another cpuset (See +Documentation/cgroups/cpusets.txt). Cpusets allows the automation of process locality. If a task is moved to a new cpuset then also all its pages are moved with it so that the performance of the process does not sink dramatically. Also the pages diff --git a/Documentation/x86/x86_64/fake-numa-for-cpusets b/Documentation/x86/x86_64/fake-numa-for-cpusets index 33bb5665599..0f11d9becb0 100644 --- a/Documentation/x86/x86_64/fake-numa-for-cpusets +++ b/Documentation/x86/x86_64/fake-numa-for-cpusets @@ -7,7 +7,8 @@ you can create fake NUMA nodes that represent contiguous chunks of memory and assign them to cpusets and their attached tasks. This is a way of limiting the amount of system memory that are available to a certain class of tasks. -For more information on the features of cpusets, see Documentation/cpusets.txt. +For more information on the features of cpusets, see +Documentation/cgroups/cpusets.txt. There are a number of different configurations you can use for your needs. For more information on the numa=fake command line option and its various ways of configuring fake nodes, see Documentation/x86/x86_64/boot-options.txt. @@ -32,7 +33,7 @@ A machine may be split as follows with "numa=fake=4*512," as reported by dmesg: On node 3 totalpages: 131072 Now following the instructions for mounting the cpusets filesystem from -Documentation/cpusets.txt, you can assign fake nodes (i.e. contiguous memory +Documentation/cgroups/cpusets.txt, you can assign fake nodes (i.e. contiguous memory address spaces) to individual cpusets: [root@xroads /]# mkdir exampleset |