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The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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- fix: initialize the robust list(s) to NULL in copy_process.
- doc update
- cleanup: rename _inuser to _inatomic
- __user cleanups and other small cleanups
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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32-bit syscall compatibility support. (This patch also moves all futex
related compat functionality into kernel/futex_compat.c.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Add the core infrastructure for robust futexes: structure definitions, the new
syscalls and the do_exit() based cleanup mechanism.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ulrich Drepper <drepper@redhat.com>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Current sched groups power calculation for allnodes_domains is wrong. We
should really be using cumulative power of the physical packages in that
group (similar to the calculation in node_domains)
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Add a new sched domain for representing multi-core with shared caches
between cores. Consider a dual package system, each package containing two
cores and with last level cache shared between cores with in a package. If
there are two runnable processes, with this appended patch those two
processes will be scheduled on different packages.
On such systems, with this patch we have observed 8% perf improvement with
specJBB(2 warehouse) benchmark and 35% improvement with CFP2000 rate(with 2
users).
This new domain will come into play only on multi-core systems with shared
caches. On other systems, this sched domain will be removed by domain
degeneration code. This new domain can be also used for implementing power
savings policy (see OLS 2005 CMP kernel scheduler paper for more details..
I will post another patch for power savings policy soon)
Most of the arch/* file changes are for cpu_coregroup_map() implementation.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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small schedule() microoptimization.
Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Is a truncation error in kernel/sched.c triggered when the nice value is
negative. The affected code is used in the TASK_INTERACTIVE macro.
The code is:
#define SCALE(v1,v1_max,v2_max) \
(v1) * (v2_max) / (v1_max)
which is used in this way:
SCALE(TASK_NICE(p), 40, MAX_BONUS)
Comments in the code says:
* This part scales the interactivity limit depending on niceness.
*
* We scale it linearly, offset by the INTERACTIVE_DELTA delta.
* Here are a few examples of different nice levels:
*
* TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0]
* TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0]
* TASK_INTERACTIVE( 0): [1,1,1,1,0,0,0,0,0,0,0]
* TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0]
* TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0]
*
* (the X axis represents the possible -5 ... 0 ... +5 dynamic
* priority range a task can explore, a value of '1' means the
* task is rated interactive.)
However, the current code does not scale it linearly and the result differs
from the given examples. If the mathematical function "floor" is used when
the nice value is negative instead of the truncation one gets when using
integer division, the result conforms to the documentation.
Output of TASK_INTERACTIVE when using the kernel code:
nice dynamic priorities
-20 1 1 1 1 1 1 1 1 1 0 0
-19 1 1 1 1 1 1 1 1 0 0 0
-18 1 1 1 1 1 1 1 1 0 0 0
-17 1 1 1 1 1 1 1 1 0 0 0
-16 1 1 1 1 1 1 1 1 0 0 0
-15 1 1 1 1 1 1 1 0 0 0 0
-14 1 1 1 1 1 1 1 0 0 0 0
-13 1 1 1 1 1 1 1 0 0 0 0
-12 1 1 1 1 1 1 1 0 0 0 0
-11 1 1 1 1 1 1 0 0 0 0 0
-10 1 1 1 1 1 1 0 0 0 0 0
-9 1 1 1 1 1 1 0 0 0 0 0
-8 1 1 1 1 1 1 0 0 0 0 0
-7 1 1 1 1 1 0 0 0 0 0 0
-6 1 1 1 1 1 0 0 0 0 0 0
-5 1 1 1 1 1 0 0 0 0 0 0
-4 1 1 1 1 1 0 0 0 0 0 0
-3 1 1 1 1 0 0 0 0 0 0 0
-2 1 1 1 1 0 0 0 0 0 0 0
-1 1 1 1 1 0 0 0 0 0 0 0
0 1 1 1 1 0 0 0 0 0 0 0
1 1 1 1 1 0 0 0 0 0 0 0
2 1 1 1 1 0 0 0 0 0 0 0
3 1 1 1 1 0 0 0 0 0 0 0
4 1 1 1 0 0 0 0 0 0 0 0
5 1 1 1 0 0 0 0 0 0 0 0
6 1 1 1 0 0 0 0 0 0 0 0
7 1 1 1 0 0 0 0 0 0 0 0
8 1 1 0 0 0 0 0 0 0 0 0
9 1 1 0 0 0 0 0 0 0 0 0
10 1 1 0 0 0 0 0 0 0 0 0
11 1 1 0 0 0 0 0 0 0 0 0
12 1 0 0 0 0 0 0 0 0 0 0
13 1 0 0 0 0 0 0 0 0 0 0
14 1 0 0 0 0 0 0 0 0 0 0
15 1 0 0 0 0 0 0 0 0 0 0
16 0 0 0 0 0 0 0 0 0 0 0
17 0 0 0 0 0 0 0 0 0 0 0
18 0 0 0 0 0 0 0 0 0 0 0
19 0 0 0 0 0 0 0 0 0 0 0
Output of TASK_INTERACTIVE when using "floor"
nice dynamic priorities
-20 1 1 1 1 1 1 1 1 1 0 0
-19 1 1 1 1 1 1 1 1 1 0 0
-18 1 1 1 1 1 1 1 1 1 0 0
-17 1 1 1 1 1 1 1 1 1 0 0
-16 1 1 1 1 1 1 1 1 0 0 0
-15 1 1 1 1 1 1 1 1 0 0 0
-14 1 1 1 1 1 1 1 1 0 0 0
-13 1 1 1 1 1 1 1 1 0 0 0
-12 1 1 1 1 1 1 1 0 0 0 0
-11 1 1 1 1 1 1 1 0 0 0 0
-10 1 1 1 1 1 1 1 0 0 0 0
-9 1 1 1 1 1 1 1 0 0 0 0
-8 1 1 1 1 1 1 0 0 0 0 0
-7 1 1 1 1 1 1 0 0 0 0 0
-6 1 1 1 1 1 1 0 0 0 0 0
-5 1 1 1 1 1 1 0 0 0 0 0
-4 1 1 1 1 1 0 0 0 0 0 0
-3 1 1 1 1 1 0 0 0 0 0 0
-2 1 1 1 1 1 0 0 0 0 0 0
-1 1 1 1 1 1 0 0 0 0 0 0
0 1 1 1 1 0 0 0 0 0 0 0
1 1 1 1 1 0 0 0 0 0 0 0
2 1 1 1 1 0 0 0 0 0 0 0
3 1 1 1 1 0 0 0 0 0 0 0
4 1 1 1 0 0 0 0 0 0 0 0
5 1 1 1 0 0 0 0 0 0 0 0
6 1 1 1 0 0 0 0 0 0 0 0
7 1 1 1 0 0 0 0 0 0 0 0
8 1 1 0 0 0 0 0 0 0 0 0
9 1 1 0 0 0 0 0 0 0 0 0
10 1 1 0 0 0 0 0 0 0 0 0
11 1 1 0 0 0 0 0 0 0 0 0
12 1 0 0 0 0 0 0 0 0 0 0
13 1 0 0 0 0 0 0 0 0 0 0
14 1 0 0 0 0 0 0 0 0 0 0
15 1 0 0 0 0 0 0 0 0 0 0
16 0 0 0 0 0 0 0 0 0 0 0
17 0 0 0 0 0 0 0 0 0 0 0
18 0 0 0 0 0 0 0 0 0 0 0
19 0 0 0 0 0 0 0 0 0 0 0
Signed-off-by: Martin Andersson <martin.andersson@control.lth.se>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Williams <pwil3058@bigpond.net.au>
Cc: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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* git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial:
drivers/char/ftape/lowlevel/fdc-io.c: Correct a comment
Kconfig help: MTD_JEDECPROBE already supports Intel
Remove ugly debugging stuff
do_mounts.c: Minor ROOT_DEV comment cleanup
BUG_ON() Conversion in drivers/s390/block/dasd_devmap.c
BUG_ON() Conversion in mm/mempool.c
BUG_ON() Conversion in mm/memory.c
BUG_ON() Conversion in kernel/fork.c
BUG_ON() Conversion in ipc/sem.c
BUG_ON() Conversion in fs/ext2/
BUG_ON() Conversion in fs/hfs/
BUG_ON() Conversion in fs/dcache.c
BUG_ON() Conversion in fs/buffer.c
BUG_ON() Conversion in input/serio/hp_sdc_mlc.c
BUG_ON() Conversion in md/dm-table.c
BUG_ON() Conversion in md/dm-path-selector.c
BUG_ON() Conversion in drivers/isdn
BUG_ON() Conversion in drivers/char
BUG_ON() Conversion in drivers/mtd/
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When kretprobe probes the schedule() function, if the probed process exits
then schedule() will never return, so some kretprobe instances will never
be recycled.
In this patch the parent process will recycle retprobe instances of the
probed function and there will be no memory leak of kretprobe instances.
Signed-off-by: bibo mao <bibo.mao@intel.com>
Cc: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The nanosleep cleanup allows to remove the data field of hrtimer. The
callback function can use container_of() to get it's own data. Since the
hrtimer structure is anyway embedded in other structures, this adds no
overhead.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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nsec_t predates ktime_t and has mostly been superseded by it. In the few
places that are left it's better to make it explicit that we're dealing with
64 bit values here.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Remove the state field and encode this information in the rb_node similiar to
normal timer.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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nanosleep is the only user of the expired state, so let it manage this itself,
which makes the hrtimer code a bit simpler. The remaining time is also only
calculated if requested.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Cleanup common_timer_get() a little.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Pass current time to hrtimer_forward(). This allows to use the softirq time
in the timer base when the forward function is called from the timer callback.
Other places pass current time with a call to timer->base->get_time().
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The hrtimer softirq is called from the timer softirq every tick. Retrieve the
current time from xtime and wall_to_monotonic instead of calling
base->get_time() for each timer base. Store the time in the base structure
and provide a hook once clock source abstractions are in place and to keep the
code open for new base clocks.
Based on a patch from: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Create compat_sys_adjtimex and use it an all appropriate places.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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If there's an error in load_image() we should return that without checking
snapshot_image_loaded.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Warn if free_irq() is called in IRQ context - free_irq() can execute /proc
VFS work, which must not be done in IRQ context.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
* 'audit.b3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: (22 commits)
[PATCH] fix audit_init failure path
[PATCH] EXPORT_SYMBOL patch for audit_log, audit_log_start, audit_log_end and audit_format
[PATCH] sem2mutex: audit_netlink_sem
[PATCH] simplify audit_free() locking
[PATCH] Fix audit operators
[PATCH] promiscuous mode
[PATCH] Add tty to syscall audit records
[PATCH] add/remove rule update
[PATCH] audit string fields interface + consumer
[PATCH] SE Linux audit events
[PATCH] Minor cosmetic cleanups to the code moved into auditfilter.c
[PATCH] Fix audit record filtering with !CONFIG_AUDITSYSCALL
[PATCH] Fix IA64 success/failure indication in syscall auditing.
[PATCH] Miscellaneous bug and warning fixes
[PATCH] Capture selinux subject/object context information.
[PATCH] Exclude messages by message type
[PATCH] Collect more inode information during syscall processing.
[PATCH] Pass dentry, not just name, in fsnotify creation hooks.
[PATCH] Define new range of userspace messages.
[PATCH] Filter rule comparators
...
Fixed trivial conflict in security/selinux/hooks.c
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* git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: (21 commits)
BUG_ON() Conversion in drivers/video/
BUG_ON() Conversion in drivers/parisc/
BUG_ON() Conversion in drivers/block/
BUG_ON() Conversion in sound/sparc/cs4231.c
BUG_ON() Conversion in drivers/s390/block/dasd.c
BUG_ON() Conversion in lib/swiotlb.c
BUG_ON() Conversion in kernel/cpu.c
BUG_ON() Conversion in ipc/msg.c
BUG_ON() Conversion in block/elevator.c
BUG_ON() Conversion in fs/coda/
BUG_ON() Conversion in fs/binfmt_elf_fdpic.c
BUG_ON() Conversion in input/serio/hil_mlc.c
BUG_ON() Conversion in md/dm-hw-handler.c
BUG_ON() Conversion in md/bitmap.c
The comment describing how MS_ASYNC works in msync.c is confusing
rcu: undeclared variable used in documentation
fix typos "wich" -> "which"
typo patch for fs/ufs/super.c
Fix simple typos
tabify drivers/char/Makefile
...
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This removes the support for pps. It's completely unused within the kernel
and is basically in the way for further cleanups. It should be easier to
readd proper support for it after the rest has been converted to NTP4
(where the pps mechanisms are quite different from NTP3 anyway).
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: Adrian Bunk <bunk@stusta.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Add support for SA_PERCPU_IRQ (only mmtimer.c uses this at this stage).
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch avoids arithmetic on 'signed' types that are slower than
'unsigned'. This saves space and cpu cycles.
size of kernel/sys.o before the patch (gcc-3.4.5)
text data bss dec hex filename
10924 252 4 11180 2bac kernel/sys.o
size of kernel/sys.o after the patch
text data bss dec hex filename
10903 252 4 11159 2b97 kernel/sys.o
I noticed that gcc-4.1.0 (from Fedora Core 5) even uses idiv instruction for
(a+b)/2 if a and b are signed.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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- Moved check for online cpu out of smp_prepare_cpu()
- Moved default declaration of smp_prepare_cpu() to kernel/cpu.c
- Removed lock_cpu_hotplug() from smp_prepare_cpu() to around it, since
its called from cpu_up() as well now.
- Removed clearing from cpu_present_map during cpu_offline as it breaks
using cpu_up() directly during a subsequent online operation.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: "Li, Shaohua" <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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in_group_p() and in_egroup_p()
While doing some benchmarks of an Apache/PHP SMP server, I noticed high
oprofile numbers in in_group_p() and _atomic_dec_and_lock().
rank percent
1 4.8911 % __link_path_walk
2 4.8503 % __d_lookup
*3 4.2911 % _atomic_dec_and_lock
4 3.9307 % __copy_to_user_ll
5 4.9004 % sysenter_past_esp
*6 3.3248 % in_group_p
It appears that in_group_p() does an uncessary
get_group_info(current->group_info); /* atomic_inc() */
... /* access current->group_info */
put_group_info(current->group_info); /* _atomic_dec_and_lock */
It is not necessary to do this, because the current task holds a reference
on its own group_info, and this reference cannot change during the lookup.
This patch deletes the get_group_info()/put_group_info() pair from
sys_getgroups(), in_group_p() and in_egroup_p() functions.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Tim Hockin <thockin@hockin.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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A couple of places are forgetting to take it.
The kswapd case is probably unimportant. keventd_create_kthread() was racy.
The whole thing is a bit flakey: you start a kernel thread, get its pid from
kernel_thread() then look up its task_struct.
a) It assumes that pid recycling takes a "long" time.
b) We get a task_struct but no reference was taken on it. The owner of the
kswapd and kthread task_struct*'s must assume that the new thread won't
exit unexpectedly. Because if it does, they're left holding dead memory
and any attempt to control or stop that task will crash.
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Move capable() to kernel/capability.c and eliminate duplicate
implementations. Add __capable() function which can be used to check for
capabiilty of any process.
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This fix prevents re-disabling and enabling of a previously disabled
interrupt. On an SMP system with irq balancing enabled; If an interrupt is
disabled from within its own interrupt context with disable_irq_nosync and is
also earmarked for processor migration, the interrupt is blindly moved to the
other processor and enabled without regard for its current "enabled" state.
If there is an interrupt pending, it will unexpectedly invoke the irq handler
on the new irq owning processor (even though the irq was previously disabled)
The more intuitive fix would be to invoke disable_irq_nosync and
enable_irq, but since we already have the desc->lock from __do_IRQ, we
cannot call them directly. Instead we can use the same logic to disable
and enable found in disable_irq_nosync and enable_irq, with regards to the
desc->depth.
This now prevents a disabled interrupt from being re-disabled, and more
importantly prevents a disabled interrupt from being incorrectly enabled on
a different processor.
Signed-off-by: Bryan Holty <lgeek@frontiernet.net>
Cc: Andi Kleen <ak@muc.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Uninline some massive IRQ migration functions. Put them in the new
kernel/irq/migration.c.
Cc: Andi Kleen <ak@muc.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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param_array() in kernel/params.c can now become static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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MODULE_PARM was actually breaking: recent gcc version optimize them out as
unused. It's time to replace the last users, which are generally in the
most unloved drivers anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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According to the specification the timevals must be validated and an
errorcode -EINVAL returned in case the timevals are not in canonical form.
This check was never done in Linux.
The pre 2.6.16 code converted invalid timevals silently. Negative timeouts
were converted by the timeval_to_jiffies conversion to the maximum timeout.
hrtimers and the ktime_t operations expect timevals in canonical form.
Otherwise random results might happen on 32 bits machines due to the
optimized ktime_add/sub operations. Negative timeouts are treated as
already expired. This might break applications which work on pre 2.6.16.
To prevent random behaviour and API breakage the timevals are checked and
invalid timevals sanitized in a simliar way as the pre 2.6.16 code did.
Invalid timevals are reported with a per boot limited number of kernel
messages so applications which use this misfeature can be corrected.
After a grace period of one year the sanitizing should be replaced by a
correct validation check. This is also documented in
Documentation/feature-removal-schedule.txt
The validation and sanitizing is done inside do_setitimer so all callers
(sys_setitimer, compat_sys_setitimer, osf_setitimer) are catched.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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alarm() calls the kernel with an unsigend int timeout in seconds. The
value is stored in the tv_sec field of a struct timeval to setup the
itimer. The tv_sec field of struct timeval is of type long, which causes
the tv_sec value to be negative on 32 bit machines if seconds > INT_MAX.
Before the hrtimer merge (pre 2.6.16) such a negative value was converted
to the maximum jiffies timeout by the timeval_to_jiffies conversion. It's
not clear whether this was intended or just happened to be done by the
timeval_to_jiffies code.
hrtimers expect a timeval in canonical form and treat a negative timeout as
already expired. This breaks the legitimate usage of alarm() with a
timeout value > INT_MAX seconds.
For 32 bit machines it is therefor necessary to limit the internal seconds
value to avoid API breakage. Instead of doing this in all implementations
of sys_alarm the duplicated sys_alarm code is moved into a common function
in itimer.c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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I seem to have lost this hunk in yesterday's patch. It brings the
coming-online CPU's softlockup timer up to date so we don't get false-positive
tripups during CPU hot-add.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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uevent_seqnum and uevent_helper are only defined if CONFIG_HOTPLUG=y,
CONFIG_NET=n.
(I stole this back from Greg's tree - it makes allnoconfig work).
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Change hand-coded userspace string copying to strndup_user.
Signed-off-by: Davi Arnaut <davi.arnaut@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Make the softlockup detector purely timer-interrupt driven, removing
softirq-context (timer) dependencies. This means that if the softlockup
watchdog triggers, it has truly observed a longer than 10 seconds
scheduling delay of a SCHED_FIFO prio 99 task.
(the patch also turns off the softlockup detector during the initial bootup
phase and does small style fixes)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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If the change of personality does not lead to change of exec domain,
__set_personality() returned without releasing the module reference
acquired by lookup_exec_domain().
Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Document the fact that setrlimit(RLIMIT_CPU) doesn't return error codes when
it should. I don't think we can fix this without a 2.7.x..
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ulrich Weigand <uweigand@de.ibm.com>
Cc: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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At present the kernel doesn't honour an attempt to set RLIMIT_CPU to zero
seconds. But the spec says it should, and that's what 2.4.x does.
Fixing this for real would involve some complexity (such as adding a new
it-has-been-set flag to the task_struct, and testing that everwhere, instead
of overloading the value of it_prof_expires).
Given that a 2.4 kernel won't actually send the signal until one second has
expired anyway, let's just handle this case by treating the caller's
zero-seconds as one second.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ulrich Weigand <uweigand@de.ibm.com>
Cc: Cliff Wickman <cpw@sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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- Whitespace cleanups
- Make that expression comprehensible.
There's a potential logic change here: we do the "is it_prof_expires equal to
zero" test after converting it to seconds, rather than doing the comparison
between raw cputime_t's.
But given that it's in units of seconds anyway, that shouldn't change
anything.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ulrich Weigand <uweigand@de.ibm.com>
Cc: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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It appears that console_setup() code only gets compiled into the kernel if
CONFIG_PRINTK is enabled. One detrimental side-effect of this is that
serial8250_console_setup() never gets invoked when CONFIG_PRINTK is not
set, resulting in baud rate not being read/parsed from command line (i.e.
console=ttyS0,115200n8 is ignored, at least the baud rate part...)
Attached patch moves console_setup() code from inside
#ifdef CONFIG_PRINTK
to outside (in printk.c), removing dependence on said config. option.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Remove a useless variable initialization in cpuset __cpuset_zone_allowed().
The local variable 'allowed' is unconditionally set before use, later on
in the code, so does not need to be initialized.
Not that it seems to matter to the code generated any, as the compiler
optimizes out the superfluous assignment anyway.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Drop the atomic_t marking on the cpuset static global
cpuset_mems_generation. Since all access to it is guarded by the global
manage_mutex, there is no need for further serialization of this value.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Remove a no longer needed test for NULL cpuset pointer, with a little
comment explaining why the test isn't needed.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The hooks in the slab cache allocator code path for support of NUMA
mempolicies and cpuset memory spreading are in an important code path. Many
systems will use neither feature.
This patch optimizes those hooks down to a single check of some bits in the
current tasks task_struct flags. For non NUMA systems, this hook and related
code is already ifdef'd out.
The optimization is done by using another task flag, set if the task is using
a non-default NUMA mempolicy. Taking this flag bit along with the
PF_SPREAD_PAGE and PF_SPREAD_SLAB flag bits added earlier in this 'cpuset
memory spreading' patch set, one can check for the combination of any of these
special case memory placement mechanisms with a single test of the current
tasks task_struct flags.
This patch also tightens up the code, to save a few bytes of kernel text
space, and moves some of it out of line. Due to the nested inlines called
from multiple places, we were ending up with three copies of this code, which
once we get off the main code path (for local node allocation) seems a bit
wasteful of instruction memory.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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