diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block | 34 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-css | 35 | ||||
| -rw-r--r-- | Documentation/block/data-integrity.txt | 327 | ||||
| -rw-r--r-- | Documentation/ftrace.txt | 134 | ||||
| -rw-r--r-- | Documentation/ioctl-number.txt | 1 | ||||
| -rw-r--r-- | Documentation/sound/alsa/ALSA-Configuration.txt | 17 | ||||
| -rw-r--r-- | Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl | 4 |
7 files changed, 484 insertions, 68 deletions
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index 4bd9ea53912..44f52a4f590 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -26,3 +26,37 @@ Description: I/O statistics of partition <part>. The format is the same as the above-written /sys/block/<disk>/stat format. + + +What: /sys/block/<disk>/integrity/format +Date: June 2008 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Metadata format for integrity capable block device. + E.g. T10-DIF-TYPE1-CRC. + + +What: /sys/block/<disk>/integrity/read_verify +Date: June 2008 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Indicates whether the block layer should verify the + integrity of read requests serviced by devices that + support sending integrity metadata. + + +What: /sys/block/<disk>/integrity/tag_size +Date: June 2008 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Number of bytes of integrity tag space available per + 512 bytes of data. + + +What: /sys/block/<disk>/integrity/write_generate +Date: June 2008 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Indicates whether the block layer should automatically + generate checksums for write requests bound for + devices that support receiving integrity metadata. diff --git a/Documentation/ABI/testing/sysfs-bus-css b/Documentation/ABI/testing/sysfs-bus-css new file mode 100644 index 00000000000..b585ec258a0 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-css @@ -0,0 +1,35 @@ +What: /sys/bus/css/devices/.../type +Date: March 2008 +Contact: Cornelia Huck <cornelia.huck@de.ibm.com> + linux-s390@vger.kernel.org +Description: Contains the subchannel type, as reported by the hardware. + This attribute is present for all subchannel types. + +What: /sys/bus/css/devices/.../modalias +Date: March 2008 +Contact: Cornelia Huck <cornelia.huck@de.ibm.com> + linux-s390@vger.kernel.org +Description: Contains the module alias as reported with uevents. + It is of the format css:t<type> and present for all + subchannel types. + +What: /sys/bus/css/drivers/io_subchannel/.../chpids +Date: December 2002 +Contact: Cornelia Huck <cornelia.huck@de.ibm.com> + linux-s390@vger.kernel.org +Description: Contains the ids of the channel paths used by this + subchannel, as reported by the channel subsystem + during subchannel recognition. + Note: This is an I/O-subchannel specific attribute. +Users: s390-tools, HAL + +What: /sys/bus/css/drivers/io_subchannel/.../pimpampom +Date: December 2002 +Contact: Cornelia Huck <cornelia.huck@de.ibm.com> + linux-s390@vger.kernel.org +Description: Contains the PIM/PAM/POM values, as reported by the + channel subsystem when last queried by the common I/O + layer (this implies that this attribute is not neccessarily + in sync with the values current in the channel subsystem). + Note: This is an I/O-subchannel specific attribute. +Users: s390-tools, HAL diff --git a/Documentation/block/data-integrity.txt b/Documentation/block/data-integrity.txt new file mode 100644 index 00000000000..e9dc8d86adc --- /dev/null +++ b/Documentation/block/data-integrity.txt @@ -0,0 +1,327 @@ +---------------------------------------------------------------------- +1. INTRODUCTION + +Modern filesystems feature checksumming of data and metadata to +protect against data corruption. However, the detection of the +corruption is done at read time which could potentially be months +after the data was written. At that point the original data that the +application tried to write is most likely lost. + +The solution is to ensure that the disk is actually storing what the +application meant it to. Recent additions to both the SCSI family +protocols (SBC Data Integrity Field, SCC protection proposal) as well +as SATA/T13 (External Path Protection) try to remedy this by adding +support for appending integrity metadata to an I/O. The integrity +metadata (or protection information in SCSI terminology) includes a +checksum for each sector as well as an incrementing counter that +ensures the individual sectors are written in the right order. And +for some protection schemes also that the I/O is written to the right +place on disk. + +Current storage controllers and devices implement various protective +measures, for instance checksumming and scrubbing. But these +technologies are working in their own isolated domains or at best +between adjacent nodes in the I/O path. The interesting thing about +DIF and the other integrity extensions is that the protection format +is well defined and every node in the I/O path can verify the +integrity of the I/O and reject it if corruption is detected. This +allows not only corruption prevention but also isolation of the point +of failure. + +---------------------------------------------------------------------- +2. THE DATA INTEGRITY EXTENSIONS + +As written, the protocol extensions only protect the path between +controller and storage device. However, many controllers actually +allow the operating system to interact with the integrity metadata +(IMD). We have been working with several FC/SAS HBA vendors to enable +the protection information to be transferred to and from their +controllers. + +The SCSI Data Integrity Field works by appending 8 bytes of protection +information to each sector. The data + integrity metadata is stored +in 520 byte sectors on disk. Data + IMD are interleaved when +transferred between the controller and target. The T13 proposal is +similar. + +Because it is highly inconvenient for operating systems to deal with +520 (and 4104) byte sectors, we approached several HBA vendors and +encouraged them to allow separation of the data and integrity metadata +scatter-gather lists. + +The controller will interleave the buffers on write and split them on +read. This means that the Linux can DMA the data buffers to and from +host memory without changes to the page cache. + +Also, the 16-bit CRC checksum mandated by both the SCSI and SATA specs +is somewhat heavy to compute in software. Benchmarks found that +calculating this checksum had a significant impact on system +performance for a number of workloads. Some controllers allow a +lighter-weight checksum to be used when interfacing with the operating +system. Emulex, for instance, supports the TCP/IP checksum instead. +The IP checksum received from the OS is converted to the 16-bit CRC +when writing and vice versa. This allows the integrity metadata to be +generated by Linux or the application at very low cost (comparable to +software RAID5). + +The IP checksum is weaker than the CRC in terms of detecting bit +errors. However, the strength is really in the separation of the data +buffers and the integrity metadata. These two distinct buffers much +match up for an I/O to complete. + +The separation of the data and integrity metadata buffers as well as +the choice in checksums is referred to as the Data Integrity +Extensions. As these extensions are outside the scope of the protocol +bodies (T10, T13), Oracle and its partners are trying to standardize +them within the Storage Networking Industry Association. + +---------------------------------------------------------------------- +3. KERNEL CHANGES + +The data integrity framework in Linux enables protection information +to be pinned to I/Os and sent to/received from controllers that +support it. + +The advantage to the integrity extensions in SCSI and SATA is that +they enable us to protect the entire path from application to storage +device. However, at the same time this is also the biggest +disadvantage. It means that the protection information must be in a +format that can be understood by the disk. + +Generally Linux/POSIX applications are agnostic to the intricacies of +the storage devices they are accessing. The virtual filesystem switch +and the block layer make things like hardware sector size and +transport protocols completely transparent to the application. + +However, this level of detail is required when preparing the +protection information to send to a disk. Consequently, the very +concept of an end-to-end protection scheme is a layering violation. +It is completely unreasonable for an application to be aware whether +it is accessing a SCSI or SATA disk. + +The data integrity support implemented in Linux attempts to hide this +from the application. As far as the application (and to some extent +the kernel) is concerned, the integrity metadata is opaque information +that's attached to the I/O. + +The current implementation allows the block layer to automatically +generate the protection information for any I/O. Eventually the +intent is to move the integrity metadata calculation to userspace for +user data. Metadata and other I/O that originates within the kernel +will still use the automatic generation interface. + +Some storage devices allow each hardware sector to be tagged with a +16-bit value. The owner of this tag space is the owner of the block +device. I.e. the filesystem in most cases. The filesystem can use +this extra space to tag sectors as they see fit. Because the tag +space is limited, the block interface allows tagging bigger chunks by +way of interleaving. This way, 8*16 bits of information can be +attached to a typical 4KB filesystem block. + +This also means that applications such as fsck and mkfs will need +access to manipulate the tags from user space. A passthrough +interface for this is being worked on. + + +---------------------------------------------------------------------- +4. BLOCK LAYER IMPLEMENTATION DETAILS + +4.1 BIO + +The data integrity patches add a new field to struct bio when +CONFIG_BLK_DEV_INTEGRITY is enabled. bio->bi_integrity is a pointer +to a struct bip which contains the bio integrity payload. Essentially +a bip is a trimmed down struct bio which holds a bio_vec containing +the integrity metadata and the required housekeeping information (bvec +pool, vector count, etc.) + +A kernel subsystem can enable data integrity protection on a bio by +calling bio_integrity_alloc(bio). This will allocate and attach the +bip to the bio. + +Individual pages containing integrity metadata can subsequently be +attached using bio_integrity_add_page(). + +bio_free() will automatically free the bip. + + +4.2 BLOCK DEVICE + +Because the format of the protection data is tied to the physical +disk, each block device has been extended with a block integrity +profile (struct blk_integrity). This optional profile is registered +with the block layer using blk_integrity_register(). + +The profile contains callback functions for generating and verifying +the protection data, as well as getting and setting application tags. +The profile also contains a few constants to aid in completing, +merging and splitting the integrity metadata. + +Layered block devices will need to pick a profile that's appropriate +for all subdevices. blk_integrity_compare() can help with that. DM +and MD linear, RAID0 and RAID1 are currently supported. RAID4/5/6 +will require extra work due to the application tag. + + +---------------------------------------------------------------------- +5.0 BLOCK LAYER INTEGRITY API + +5.1 NORMAL FILESYSTEM + + The normal filesystem is unaware that the underlying block device + is capable of sending/receiving integrity metadata. The IMD will + be automatically generated by the block layer at submit_bio() time + in case of a WRITE. A READ request will cause the I/O integrity + to be verified upon completion. + + IMD generation and verification can be toggled using the + + /sys/block/<bdev>/integrity/write_generate + + and + + /sys/block/<bdev>/integrity/read_verify + + flags. + + +5.2 INTEGRITY-AWARE FILESYSTEM + + A filesystem that is integrity-aware can prepare I/Os with IMD + attached. It can also use the application tag space if this is + supported by the block device. + + + int bdev_integrity_enabled(block_device, int rw); + + bdev_integrity_enabled() will return 1 if the block device + supports integrity metadata transfer for the data direction + specified in 'rw'. + + bdev_integrity_enabled() honors the write_generate and + read_verify flags in sysfs and will respond accordingly. + + + int bio_integrity_prep(bio); + + To generate IMD for WRITE and to set up buffers for READ, the + filesystem must call bio_integrity_prep(bio). + + Prior to calling this function, the bio data direction and start + sector must be set, and the bio should have all data pages + added. It is up to the caller to ensure that the bio does not + change while I/O is in progress. + + bio_integrity_prep() should only be called if + bio_integrity_enabled() returned 1. + + + int bio_integrity_tag_size(bio); + + If the filesystem wants to use the application tag space it will + first have to find out how much storage space is available. + Because tag space is generally limited (usually 2 bytes per + sector regardless of sector size), the integrity framework + supports interleaving the information between the sectors in an + I/O. + + Filesystems can call bio_integrity_tag_size(bio) to find out how + many bytes of storage are available for that particular bio. + + Another option is bdev_get_tag_size(block_device) which will + return the number of available bytes per hardware sector. + + + int bio_integrity_set_tag(bio, void *tag_buf, len); + + After a successful return from bio_integrity_prep(), + bio_integrity_set_tag() can be used to attach an opaque tag + buffer to a bio. Obviously this only makes sense if the I/O is + a WRITE. + + + int bio_integrity_get_tag(bio, void *tag_buf, len); + + Similarly, at READ I/O completion time the filesystem can + retrieve the tag buffer using bio_integrity_get_tag(). + + +6.3 PASSING EXISTING INTEGRITY METADATA + + Filesystems that either generate their own integrity metadata or + are capable of transferring IMD from user space can use the + following calls: + + + struct bip * bio_integrity_alloc(bio, gfp_mask, nr_pages); + + Allocates the bio integrity payload and hangs it off of the bio. + nr_pages indicate how many pages of protection data need to be + stored in the integrity bio_vec list (similar to bio_alloc()). + + The integrity payload will be freed at bio_free() time. + + + int bio_integrity_add_page(bio, page, len, offset); + + Attaches a page containing integrity metadata to an existing + bio. The bio must have an existing bip, + i.e. bio_integrity_alloc() must have been called. For a WRITE, + the integrity metadata in the pages must be in a format + understood by the target device with the notable exception that + the sector numbers will be remapped as the request traverses the + I/O stack. This implies that the pages added using this call + will be modified during I/O! The first reference tag in the + integrity metadata must have a value of bip->bip_sector. + + Pages can be added using bio_integrity_add_page() as long as + there is room in the bip bio_vec array (nr_pages). + + Upon completion of a READ operation, the attached pages will + contain the integrity metadata received from the storage device. + It is up to the receiver to process them and verify data + integrity upon completion. + + +6.4 REGISTERING A BLOCK DEVICE AS CAPABLE OF EXCHANGING INTEGRITY + METADATA + + To enable integrity exchange on a block device the gendisk must be + registered as capable: + + int blk_integrity_register(gendisk, blk_integrity); + + The blk_integrity struct is a template and should contain the + following: + + static struct blk_integrity my_profile = { + .name = "STANDARDSBODY-TYPE-VARIANT-CSUM", + .generate_fn = my_generate_fn, + .verify_fn = my_verify_fn, + .get_tag_fn = my_get_tag_fn, + .set_tag_fn = my_set_tag_fn, + .tuple_size = sizeof(struct my_tuple_size), + .tag_size = <tag bytes per hw sector>, + }; + + 'name' is a text string which will be visible in sysfs. This is + part of the userland API so chose it carefully and never change + it. The format is standards body-type-variant. + E.g. T10-DIF-TYPE1-IP or T13-EPP-0-CRC. + + 'generate_fn' generates appropriate integrity metadata (for WRITE). + + 'verify_fn' verifies that the data buffer matches the integrity + metadata. + + 'tuple_size' must be set to match the size of the integrity + metadata per sector. I.e. 8 for DIF and EPP. + + 'tag_size' must be set to identify how many bytes of tag space + are available per hardware sector. For DIF this is either 2 or + 0 depending on the value of the Control Mode Page ATO bit. + + See 6.2 for a description of get_tag_fn and set_tag_fn. + +---------------------------------------------------------------------- +2007-12-24 Martin K. Petersen <martin.petersen@oracle.com> diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt index 13e4bf054c3..77d3faa1a61 100644 --- a/Documentation/ftrace.txt +++ b/Documentation/ftrace.txt @@ -2,8 +2,11 @@ ======================== Copyright 2008 Red Hat Inc. -Author: Steven Rostedt <srostedt@redhat.com> + Author: Steven Rostedt <srostedt@redhat.com> + License: The GNU Free Documentation License, Version 1.2 +Reviewers: Elias Oltmanns and Randy Dunlap +Writen for: 2.6.26-rc8 linux-2.6-tip.git tip/tracing/ftrace branch Introduction ------------ @@ -46,7 +49,7 @@ of ftrace. Here is a list of some of the key files: that is configured. available_tracers : This holds the different types of tracers that - has been compiled into the kernel. The tracers + have been compiled into the kernel. The tracers listed here can be configured by echoing in their name into current_tracer. @@ -90,11 +93,13 @@ of ftrace. Here is a list of some of the key files: trace_entries : This sets or displays the number of trace entries each CPU buffer can hold. The tracer buffers are the same size for each CPU, so care must be - taken when modifying the trace_entries. The number - of actually entries will be the number given - times the number of possible CPUS. The buffers - are saved as individual pages, and the actual entries - will always be rounded up to entries per page. + taken when modifying the trace_entries. The trace + buffers are allocated in pages (blocks of memory that + the kernel uses for allocation, usually 4 KB in size). + Since each entry is smaller than a page, if the last + allocated page has room for more entries than were + requested, the rest of the page is used to allocate + entries. This can only be updated when the current_tracer is set to "none". @@ -114,13 +119,13 @@ of ftrace. Here is a list of some of the key files: in performance. This also has a side effect of enabling or disabling specific functions to be traced. Echoing in names of functions into this - file will limit the trace to only those files. + file will limit the trace to only these functions. set_ftrace_notrace: This has the opposite effect that set_ftrace_filter has. Any function that is added here will not be traced. If a function exists - in both set_ftrace_filter and set_ftrace_notrace - the function will _not_ bet traced. + in both set_ftrace_filter and set_ftrace_notrace, + the function will _not_ be traced. available_filter_functions : When a function is encountered the first time by the dynamic tracer, it is recorded and @@ -138,7 +143,7 @@ Here are the list of current tracers that can be configured. ftrace - function tracer that uses mcount to trace all functions. It is possible to filter out which functions that are - traced when dynamic ftrace is configured in. + to be traced when dynamic ftrace is configured in. sched_switch - traces the context switches between tasks. @@ -297,13 +302,13 @@ explains which is which. The above is mostly meaningful for kernel developers. - time: This differs from the trace output where as the trace output - contained a absolute timestamp. This timestamp is relative - to the start of the first entry in the the trace. + time: This differs from the trace file output. The trace file output + included an absolute timestamp. The timestamp used by the + latency_trace file is relative to the start of the trace. delay: This is just to help catch your eye a bit better. And needs to be fixed to be only relative to the same CPU. - The marks is determined by the difference between this + The marks are determined by the difference between this current trace and the next trace. '!' - greater than preempt_mark_thresh (default 100) '+' - greater than 1 microsecond @@ -322,13 +327,13 @@ output. To see what is available, simply cat the file: print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \ noblock nostacktrace nosched-tree -To disable one of the options, echo in the option appended with "no". +To disable one of the options, echo in the option prepended with "no". echo noprint-parent > /debug/tracing/iter_ctrl To enable an option, leave off the "no". - echo sym-offest > /debug/tracing/iter_ctrl + echo sym-offset > /debug/tracing/iter_ctrl Here are the available options: @@ -344,7 +349,7 @@ Here are the available options: sym-offset - Display not only the function name, but also the offset in the function. For example, instead of seeing just - "ktime_get" you will see "ktime_get+0xb/0x20" + "ktime_get", you will see "ktime_get+0xb/0x20". sym-offset: bash-4000 [01] 1477.606694: simple_strtoul+0x6/0xa0 @@ -364,7 +369,7 @@ Here are the available options: user applications that can translate the raw numbers better than having it done in the kernel. - hex - similar to raw, but the numbers will be in a hexadecimal format. + hex - Similar to raw, but the numbers will be in a hexadecimal format. bin - This will print out the formats in raw binary. @@ -381,7 +386,7 @@ sched_switch ------------ This tracer simply records schedule switches. Here's an example -on how to implement it. +of how to use it. # echo sched_switch > /debug/tracing/current_tracer # echo 1 > /debug/tracing/tracing_enabled @@ -470,7 +475,7 @@ interrupt from triggering or the mouse interrupt from letting the kernel know of a new mouse event. The result is a latency with the reaction time. -The irqsoff tracer tracks the time interrupts are disabled and when +The irqsoff tracer tracks the time interrupts are disabled to the time they are re-enabled. When a new maximum latency is hit, it saves off the trace so that it may be retrieved at a later time. Every time a new maximum in reached, the old saved trace is discarded and the new @@ -519,7 +524,7 @@ The difference between the 6 and the displayed timestamp 7us is because the clock must have incremented between the time of recording the max latency and recording the function that had that latency. -Note the above had ftrace_enabled not set. If we set the ftrace_enabled +Note the above had ftrace_enabled not set. If we set the ftrace_enabled, we get a much larger output: # tracer: irqsoff @@ -570,21 +575,21 @@ vim:ft=help Here we traced a 50 microsecond latency. But we also see all the -functions that were called during that time. Note that enabling -function tracing we endure an added overhead. This overhead may -extend the latency times. But never the less, this trace has provided -some very helpful debugging. +functions that were called during that time. Note that by enabling +function tracing, we endure an added overhead. This overhead may +extend the latency times. But nevertheless, this trace has provided +some very helpful debugging information. preemptoff ---------- -When preemption is disabled we may be able to receive interrupts but -the task can not be preempted and a higher priority task must wait +When preemption is disabled, we may be able to receive interrupts but +the task cannot be preempted and a higher priority task must wait for preemption to be enabled again before it can preempt a lower priority task. -The preemptoff tracer traces the places that disables preemption. +The preemptoff tracer traces the places that disable preemption. Like the irqsoff, it records the maximum latency that preemption was disabled. The control of preemptoff is much like the irqsoff. @@ -696,7 +701,7 @@ Notice that the __do_softirq when called doesn't have a preempt_count. It may seem that we missed a preempt enabled. What really happened is that the preempt count is held on the threads stack and we switched to the softirq stack (4K stacks in effect). The code -does not copy the preempt count, but because interrupts are disabled +does not copy the preempt count, but because interrupts are disabled, we don't need to worry about it. Having a tracer like this is good to let people know what really happens inside the kernel. @@ -732,7 +737,7 @@ To record this time, use the preemptirqsoff tracer. Again, using this trace is much like the irqsoff and preemptoff tracers. - # echo preemptoff > /debug/tracing/current_tracer + # echo preemptirqsoff > /debug/tracing/current_tracer # echo 0 > /debug/tracing/tracing_max_latency # echo 1 > /debug/tracing/tracing_enabled # ls -ltr @@ -862,9 +867,9 @@ This is a very interesting trace. It started with the preemption of the ls task. We see that the task had the "need_resched" bit set with the 'N' in the trace. Interrupts are disabled in the spin_lock and the trace started. We see that a schedule took place to run -sshd. When the interrupts were enabled we took an interrupt. -On return of the interrupt the softirq ran. We took another interrupt -while running the softirq as we see with the capital 'H'. +sshd. When the interrupts were enabled, we took an interrupt. +On return from the interrupt handler, the softirq ran. We took another +interrupt while running the softirq as we see with the capital 'H'. wakeup @@ -876,9 +881,9 @@ time it executes. This is also known as "schedule latency". I stress the point that this is about RT tasks. It is also important to know the scheduling latency of non-RT tasks, but the average schedule latency is better for non-RT tasks. Tools like -LatencyTop is more appropriate for such measurements. +LatencyTop are more appropriate for such measurements. -Real-Time environments is interested in the worst case latency. +Real-Time environments are interested in the worst case latency. That is the longest latency it takes for something to happen, and not the average. We can have a very fast scheduler that may only have a large latency once in a while, but that would not work well @@ -889,8 +894,8 @@ tasks that are unpredictable will overwrite the worst case latency of RT tasks. Since this tracer only deals with RT tasks, we will run this slightly -different than we did with the previous tracers. Instead of performing -an 'ls' we will run 'sleep 1' under 'chrt' which changes the +differently than we did with the previous tracers. Instead of performing +an 'ls', we will run 'sleep 1' under 'chrt' which changes the priority of the task. # echo wakeup > /debug/tracing/current_tracer @@ -924,9 +929,9 @@ wakeup latency trace v1.1.5 on 2.6.26-rc8 vim:ft=help -Running this on an idle system we see that it only took 4 microseconds +Running this on an idle system, we see that it only took 4 microseconds to perform the task switch. Note, since the trace marker in the -schedule is before the actual "switch" we stop the tracing when +schedule is before the actual "switch", we stop the tracing when the recorded task is about to schedule in. This may change if we add a new marker at the end of the scheduler. @@ -992,12 +997,15 @@ ksoftirq-7 1d..4 50us : schedule (__cond_resched) The interrupt went off while running ksoftirqd. This task runs at SCHED_OTHER. Why didn't we see the 'N' set early? This may be -a harmless bug with x86_32 and 4K stacks. The need_reched() function -that tests if we need to reschedule looks on the actual stack. -Where as the setting of the NEED_RESCHED bit happens on the -task's stack. But because we are in a hard interrupt, the test -is with the interrupts stack which has that to be false. We don't -see the 'N' until we switch back to the task's stack. +a harmless bug with x86_32 and 4K stacks. On x86_32 with 4K stacks +configured, the interrupt and softirq runs with their own stack. +Some information is held on the top of the task's stack (need_resched +and preempt_count are both stored there). The setting of the NEED_RESCHED +bit is done directly to the task's stack, but the reading of the +NEED_RESCHED is done by looking at the current stack, which in this case +is the stack for the hard interrupt. This hides the fact that NEED_RESCHED +has been set. We don't see the 'N' until we switch back to the task's +assigned stack. ftrace ------ @@ -1067,10 +1075,10 @@ this works is the mcount function call (placed at the start of every kernel function, produced by the -pg switch in gcc), starts of pointing to a simple return. -When dynamic ftrace is initialized, it calls kstop_machine to make it -act like a uniprocessor so that it can freely modify code without -worrying about other processors executing that same code. At -initialization, the mcount calls are change to call a "record_ip" +When dynamic ftrace is initialized, it calls kstop_machine to make +the machine act like a uniprocessor so that it can freely modify code +without worrying about other processors executing that same code. At +initialization, the mcount calls are changed to call a "record_ip" function. After this, the first time a kernel function is called, it has the calling address saved in a hash table. @@ -1085,8 +1093,8 @@ traced, is that we can now selectively choose which functions we want to trace and which ones we want the mcount calls to remain as nops. -Two files that contain to the enabling and disabling of recorded -functions are: +Two files are used, one for enabling and one for disabling the tracing +of recorded functions. They are: set_ftrace_filter @@ -1094,7 +1102,7 @@ and set_ftrace_notrace -A list of available functions that you can add to this files is listed +A list of available functions that you can add to these files is listed in: available_filter_functions @@ -1133,9 +1141,9 @@ sys_nanosleep Perhaps this isn't enough. The filters also allow simple wild cards. -Only the following is currently available +Only the following are currently available - <match>* - will match functions that begins with <match> + <match>* - will match functions that begin with <match> *<match> - will match functions that end with <match> *<match>* - will match functions that have <match> in it @@ -1187,7 +1195,7 @@ This is because the '>' and '>>' act just like they do in bash. To rewrite the filters, use '>' To append to the filters, use '>>' -To clear out a filter so that all functions will be recorded again. +To clear out a filter so that all functions will be recorded again: # echo > /debug/tracing/set_ftrace_filter # cat /debug/tracing/set_ftrace_filter @@ -1246,8 +1254,8 @@ ftraced As mentioned above, when dynamic ftrace is configured in, a kernel thread wakes up once a second and checks to see if there are mcount -calls that need to be converted into nops. If there is not, then -it simply goes back to sleep. But if there is, it will call +calls that need to be converted into nops. If there are not any, then +it simply goes back to sleep. But if there are some, it will call kstop_machine to convert the calls to nops. There may be a case that you do not want this added latency. @@ -1262,8 +1270,8 @@ mcount calls to nops. Remember that there's a large overhead to calling mcount. Without this kernel thread, that overhead will exist. -Any write to the ftraced_enabled file will cause the kstop_machine -to run if there are recorded calls to mcount. This means that a +If there are recorded calls to mcount, any write to the ftraced_enabled +file will cause the kstop_machine to run. This means that a user can manually perform the updates when they want to by simply echoing a '0' into the ftraced_enabled file. @@ -1315,7 +1323,7 @@ trace entries Having too much or not enough data can be troublesome in diagnosing some issue in the kernel. The file trace_entries is used to modify -the size of the internal trace buffers. The numbers listed +the size of the internal trace buffers. The number listed is the number of entries that can be recorded per CPU. To know the full size, multiply the number of possible CPUS with the number of entries. @@ -1323,7 +1331,7 @@ number of entries. # cat /debug/tracing/trace_entries 65620 -Note, to modify this you must have tracing fulling disabled. To do that, +Note, to modify this, you must have tracing completely disabled. To do that, echo "none" into the current_tracer. # echo none > /debug/tracing/current_tracer @@ -1344,7 +1352,7 @@ it will add them. This shows us that 85 entries can fit on a single page. The number of pages that will be allocated is a percentage of available -memory. Allocating too much will produces an error. +memory. Allocating too much will produce an error. # echo 1000000000000 > /debug/tracing/trace_entries -bash: echo: write error: Cannot allocate memory diff --git a/Documentation/ioctl-number.txt b/Documentation/ioctl-number.txt index 240ce7a56c4..3bb5f466a90 100644 --- a/Documentation/ioctl-number.txt +++ b/Documentation/ioctl-number.txt @@ -117,6 +117,7 @@ Code Seq# Include File Comments <mailto:natalia@nikhefk.nikhef.nl> 'c' 00-7F linux/comstats.h conflict! 'c' 00-7F linux/coda.h conflict! +'c' 80-9F asm-s390/chsc.h 'd' 00-FF linux/char/drm/drm/h conflict! 'd' 00-DF linux/video_decoder.h conflict! 'd' F0-FF linux/digi1.h diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index 0bbee38acd2..72aff61e731 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -753,8 +753,11 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. [Multiple options for each card instance] model - force the model name - position_fix - Fix DMA pointer (0 = auto, 1 = none, 2 = POSBUF, 3 = FIFO size) + position_fix - Fix DMA pointer (0 = auto, 1 = use LPIB, 2 = POSBUF) probe_mask - Bitmask to probe codecs (default = -1, meaning all slots) + bdl_pos_adj - Specifies the DMA IRQ timing delay in samples. + Passing -1 will make the driver to choose the appropriate + value based on the controller chip. [Single (global) options] single_cmd - Use single immediate commands to communicate with @@ -845,7 +848,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. ALC269 basic Basic preset - ALC662 + ALC662/663 3stack-dig 3-stack (2-channel) with SPDIF 3stack-6ch 3-stack (6-channel) 3stack-6ch-dig 3-stack (6-channel) with SPDIF @@ -853,6 +856,10 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. lenovo-101e Lenovo laptop eeepc-p701 ASUS Eeepc P701 eeepc-ep20 ASUS Eeepc EP20 + m51va ASUS M51VA + g71v ASUS G71V + h13 ASUS H13 + g50v ASUS G50V auto auto-config reading BIOS (default) ALC882/885 @@ -1091,7 +1098,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. This occurs when the access to non-existing or non-working codec slot (likely a modem one) causes a stall of the communication via HD-audio bus. You can see which codec slots are probed by enabling - CONFIG_SND_DEBUG_DETECT, or simply from the file name of the codec + CONFIG_SND_DEBUG_VERBOSE, or simply from the file name of the codec proc files. Then limit the slots to probe by probe_mask option. For example, probe_mask=1 means to probe only the first slot, and probe_mask=4 means only the third slot. @@ -2267,6 +2274,10 @@ case above again, the first two slots are already reserved. If any other driver (e.g. snd-usb-audio) is loaded before snd-interwave or snd-ens1371, it will be assigned to the third or later slot. +When a module name is given with '!', the slot will be given for any +modules but that name. For example, "slots=!snd-pcsp" will reserve +the first slot for any modules but snd-pcsp. + ALSA PCM devices to OSS devices mapping ======================================= diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl index b03df4d4795..e13c4e67029 100644 --- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl +++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl @@ -6127,8 +6127,8 @@ struct _snd_pcm_runtime { <para> <function>snd_printdd()</function> is compiled in only when - <constant>CONFIG_SND_DEBUG_DETECT</constant> is set. Please note - that <constant>DEBUG_DETECT</constant> is not set as default + <constant>CONFIG_SND_DEBUG_VERBOSE</constant> is set. Please note + that <constant>CONFIG_SND_DEBUG_VERBOSE</constant> is not set as default even if you configure the alsa-driver with <option>--with-debug=full</option> option. You need to give explicitly <option>--with-debug=detect</option> option instead. |