Commit Graph

11856 Commits

Author SHA1 Message Date
Rafael J. Wysocki 9744997a8a PM / Hibernate: Make snapshot_release() restore GFP mask
If the process using the hibernate user space interface closes
/dev/snapshot after creating a hibernation image without thawing
tasks, snapshot_release() should call pm_restore_gfp_mask() to
restore the GFP mask used before the creation of the image.  Make
that happen.

Tested-by: Alexandre Felipe Muller de Souza <alexandrefm@mandriva.com.br>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
2011-05-11 21:10:43 +02:00
Rafael J. Wysocki 87186475a4 PM: Fix warning in pm_restrict_gfp_mask() during SNAPSHOT_S2RAM ioctl
A warning is printed by pm_restrict_gfp_mask() while the
SNAPSHOT_S2RAM ioctl is being executed after creating a hibernation
image, because pm_restrict_gfp_mask() has been called once already
before the image creation and suspend_devices_and_enter() calls it
once again.  This happens after commit 452aa6999e
(mm/pm: force GFP_NOIO during suspend/hibernation and resume).

To avoid this issue, move pm_restrict_gfp_mask() and
pm_restore_gfp_mask() from suspend_devices_and_enter() to its caller
in kernel/power/suspend.c.

Reported-by: Alexandre Felipe Muller de Souza <alexandrefm@mandriva.com.br>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
2011-05-11 21:10:14 +02:00
Eric W. Biederman 34482e89a5 ns proc: Add support for the uts namespace
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2011-05-10 14:35:35 -07:00
Eric W. Biederman 0663c6f8fa ns: Introduce the setns syscall
With the networking stack today there is demand to handle
multiple network stacks at a time.  Not in the context
of containers but in the context of people doing interesting
things with routing.

There is also demand in the context of containers to have
an efficient way to execute some code in the container itself.
If nothing else it is very useful ad a debugging technique.

Both problems can be solved by starting some form of login
daemon in the namespaces people want access to, or you
can play games by ptracing a process and getting the
traced process to do things you want it to do. However
it turns out that a login daemon or a ptrace puppet
controller are more code, they are more prone to
failure, and generally they are less efficient than
simply changing the namespace of a process to a
specified one.

Pieces of this puzzle can also be solved by instead of
coming up with a general purpose system call coming up
with targed system calls perhaps socketat that solve
a subset of the larger problem.  Overall that appears
to be more work for less reward.

int setns(int fd, int nstype);

The fd argument is a file descriptor referring to a proc
file of the namespace you want to switch the process to.

In the setns system call the nstype is 0 or specifies
an clone flag of the namespace you intend to change
to prevent changing a namespace unintentionally.

v2: Most of the architecture support added by Daniel Lezcano <dlezcano@fr.ibm.com>
v3: ported to v2.6.36-rc4 by: Eric W. Biederman <ebiederm@xmission.com>
v4: Moved wiring up of the system call to another patch
v5: Cleaned up the system call arguments
    - Changed the order.
    - Modified nstype to take the standard clone flags.
v6: Added missing error handling as pointed out by Matt Helsley <matthltc@us.ibm.com>

Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2011-05-10 14:32:56 -07:00
Ingo Molnar 932fed4e2e Merge commit 'v2.6.39-rc7' into perf/core
Merge reason: pull in the latest fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-10 17:05:45 +02:00
Tejun Heo 40ae717d1e ptrace: fix signal->wait_chldexit usage in task_clear_group_stop_trapping()
GROUP_STOP_TRAPPING waiting mechanism piggybacks on
signal->wait_chldexit which is primarily used to implement waiting for
wait(2) and friends.  When do_wait() waits on signal->wait_chldexit,
it uses a custom wake up callback, child_wait_callback(), which
expects the child task which is waking up the parent to be passed in
as @key to filter out spurious wakeups.

task_clear_group_stop_trapping() used __wake_up_sync() which uses NULL
@key causing the following oops if the parent was doing do_wait().

  BUG: unable to handle kernel NULL pointer dereference at 00000000000002d8
  IP: [<ffffffff810499f9>] child_wait_callback+0x29/0x80
  PGD 1d899067 PUD 1e418067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP
  last sysfs file: /sys/devices/pci0000:00/0000:00:03.0/local_cpus
  CPU 2
  Modules linked in:

  Pid: 4498, comm: test-continued Not tainted 2.6.39-rc6-work+ #32 Bochs Bochs
  RIP: 0010:[<ffffffff810499f9>]  [<ffffffff810499f9>] child_wait_callback+0x29/0x80
  RSP: 0000:ffff88001b889bf8  EFLAGS: 00010046
  RAX: 0000000000000000 RBX: ffff88001fab3af8 RCX: 0000000000000000
  RDX: 0000000000000001 RSI: 0000000000000002 RDI: ffff88001d91df20
  RBP: ffff88001b889c08 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
  R13: ffff88001fb70550 R14: 0000000000000000 R15: 0000000000000001
  FS:  00007f26ccae4700(0000) GS:ffff88001fd00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 00000000000002d8 CR3: 000000001b8ac000 CR4: 00000000000006e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  Process test-continued (pid: 4498, threadinfo ffff88001b888000, task ffff88001fb88000)
  Stack:
   ffff88001b889c18 ffff88001fb70538 ffff88001b889c58 ffffffff810312f9
   0000000000000001 0000000200000001 ffff88001b889c58 ffff88001fb70518
   0000000000000002 0000000000000082 0000000000000001 0000000000000000
  Call Trace:
   [<ffffffff810312f9>] __wake_up_common+0x59/0x90
   [<ffffffff81035263>] __wake_up_sync_key+0x53/0x80
   [<ffffffff810352a0>] __wake_up_sync+0x10/0x20
   [<ffffffff8105a984>] task_clear_jobctl_trapping+0x44/0x50
   [<ffffffff8105bcbc>] ptrace_stop+0x7c/0x290
   [<ffffffff8105c20a>] do_signal_stop+0x28a/0x2d0
   [<ffffffff8105d27f>] get_signal_to_deliver+0x14f/0x5a0
   [<ffffffff81002175>] do_signal+0x75/0x7b0
   [<ffffffff8100292d>] do_notify_resume+0x5d/0x70
   [<ffffffff8182e36a>] retint_signal+0x46/0x8c
  Code: 00 00 55 48 89 e5 53 48 83 ec 08 0f 1f 44 00 00 8b 47 d8 83 f8 03 74 3a 85 c0 49 89 c8 75 23 89 c0 48 8b 5f e0 4c 8d 0c 40 31 c0 <4b> 39 9c c8 d8 02 00 00 74 1d 48 83 c4 08 5b c9 c3 66 0f 1f 44

Fix it by using __wake_up_sync_key() and passing in the child as @key.

I still think it's a mistake to piggyback on wait_chldexit for this.
Given the relative low frequency of ptrace use, we would be much
better off leaving already complex wait_chldexit alone and using bit
waitqueue.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
2011-05-09 14:19:54 +02:00
Oleg Nesterov 2e4f7c7769 signal: sys_sigprocmask() needs retarget_shared_pending()
sys_sigprocmask() changes current->blocked by hand. Convert this code
to use set_current_blocked().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2011-05-09 13:48:56 +02:00
Lai Jiangshan fa4bbc4ca5 perf,rcu: convert call_rcu(swevent_hlist_release_rcu) to kfree_rcu()
The rcu callback swevent_hlist_release_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(swevent_hlist_release_rcu).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-07 22:51:09 -07:00
Lai Jiangshan cb796ff338 perf,rcu: convert call_rcu(free_ctx) to kfree_rcu()
The rcu callback free_ctx() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(free_ctx).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-07 22:51:08 -07:00
Lai Jiangshan 025cea99db cgroup,rcu: convert call_rcu(__free_css_id_cb) to kfree_rcu()
The rcu callback __free_css_id_cb() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(__free_css_id_cb).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-07 22:50:47 -07:00
Lai Jiangshan f2da1c40dc cgroup,rcu: convert call_rcu(free_cgroup_rcu) to kfree_rcu()
The rcu callback free_cgroup_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(free_cgroup_rcu).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-07 22:50:46 -07:00
Lai Jiangshan 30088ad815 cgroup,rcu: convert call_rcu(free_css_set_rcu) to kfree_rcu()
The rcu callback free_css_set_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(free_css_set_rcu).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-07 22:50:45 -07:00
Paul E. McKenney 1217ed1ba5 rcu: permit rcu_read_unlock() to be called while holding runqueue locks
Avoid calling into the scheduler while holding core RCU locks.  This
allows rcu_read_unlock() to be called while holding the runqueue locks,
but only as long as there was no chance of the RCU read-side critical
section having been preempted.  (Otherwise, if RCU priority boosting
is enabled, rcu_read_unlock() might call into the scheduler in order to
unboost itself, which might allows self-deadlock on the runqueue locks
within the scheduler.)

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-07 22:50:45 -07:00
Linus Torvalds 8b061610da Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf tools: Makefile: Use gcc to determine ARCH
  perf events, x86: Fix Intel Nehalem and Westmere last level cache event definitions
  hw_breakpoints, powerpc: Fix CONFIG_HAVE_HW_BREAKPOINT off-case in ptrace_set_debugreg()
  sh, hw_breakpoints: Fix racy access to ptrace breakpoints
  arm, hw_breakpoints: Fix racy access to ptrace breakpoints
  powerpc, hw_breakpoints: Fix racy access to ptrace breakpoints
  x86, hw_breakpoints: Fix racy access to ptrace breakpoints
  ptrace: Prepare to fix racy accesses on task breakpoints
2011-05-07 13:17:37 -07:00
Kay Sievers b50fa7c807 reboot: disable usermodehelper to prevent fs access
In case CONFIG_UEVENT_HELPER_PATH is not set to "", which it
should be on every system, the kernel forks processes during
shutdown, which try to access the rootfs, even when the
binary does not exist. It causes exceptions and long delays in
the disk driver, which gets read requests at the time it tries
to shut down the disk.

This patch disables all kernel-forked processes during reboot to
allow a clean poweroff.

Cc: Tejun Heo <htejun@gmail.com>
Tested-By: Anton Guda <atu@dmeti.dp.ua>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-06 17:52:32 -07:00
Arjan van de Ven a3a4a5acd3 Regression: partial revert "tracing: Remove lock_depth from event entry"
This partially reverts commit e6e1e25935.

That commit changed the structure layout of the trace structure, which
in turn broke PowerTOP (1.9x generation) quite badly.

I appreciate not wanting to expose the variable in question, and
PowerTOP was not using it, so I've replaced the variable with just a
padding field - that way if in the future a new field is needed it can
just use this padding field.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-06 13:20:59 -07:00
Hillf Danton 7142d17e8f sched: Shorten the construction of the span cpu mask of sched domain
For a given node, when constructing the cpumask for its
sched_domain to span, if there is no best node available after
searching, further efforts could be saved, based on small change
in the return value of find_next_best_node().

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Link: http://lkml.kernel.org/r/BANLkTi%3DqPWxRAa6%2BdT3ohEP6Z%3D0v%2Be4EXA@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-06 09:13:05 +02:00
Rakib Mullick 4934a4d3d3 sched: Wrap the 'cfs_rq->nr_spread_over' field with CONFIG_SCHED_DEBUG
cfs_rq->nr_spread_over is only used when CONFIG_SCHED_DEBUG is set.
So wrap it with CONFIG_SCHED_DEBUG.

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1304528026.15681.3.camel@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-06 09:04:19 +02:00
Gleb Natapov 29ce831000 rcu: provide rcu_virt_note_context_switch() function.
Provide rcu_virt_note_context_switch() for vitalization use to note
quiescent state during guest entry.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-05 23:16:59 -07:00
Paul E. McKenney bad6e1393c rcu: get rid of signed overflow in check_cpu_stall()
Signed integer overflow is undefined by the C standard, so move
calculations to unsigned.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-05 23:16:59 -07:00
Eric Dumazet b554d7de8d rcu: optimize rcutiny
rcu_sched_qs() currently calls local_irq_save()/local_irq_restore() up
to three times.

Remove irq masking from rcu_qsctr_help() / invoke_rcu_kthread()
and do it once in rcu_sched_qs() / rcu_bh_qs()

This generates smaller code as well.

   text	   data	    bss	    dec	    hex	filename
   2314	    156	     24	   2494	    9be	kernel/rcutiny.old.o
   2250	    156	     24	   2430	    97e	kernel/rcutiny.new.o

Fix an outdated comment for rcu_qsctr_help()
Move invoke_rcu_kthread() definition before its use.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:59 -07:00
Paul E. McKenney 2655d57ef3 rcu: prevent call_rcu() from diving into rcu core if irqs disabled
This commit marks a first step towards making call_rcu() have
real-time behavior.  If irqs are disabled, don't dive into the
RCU core.  Later on, this new early exit will wake up the
per-CPU kthread, which first must be modified to handle the
cases involving callback storms.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:59 -07:00
Paul E. McKenney baa1ae0c9f rcu: further lower priority in rcu_yield()
Although rcu_yield() dropped from real-time to normal priority, there
is always the possibility that the competing tasks have been niced.
So nice to 19 in rcu_yield() to help ensure that other tasks have a
better chance of running.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:59 -07:00
Lai Jiangshan 9ab1544eb4 rcu: introduce kfree_rcu()
Many rcu callbacks functions just call kfree() on the base structure.
These functions are trivial, but their size adds up, and furthermore
when they are used in a kernel module, that module must invoke the
high-latency rcu_barrier() function at module-unload time.

The kfree_rcu() function introduced by this commit addresses this issue.
Rather than encoding a function address in the embedded rcu_head
structure, kfree_rcu() instead encodes the offset of the rcu_head
structure within the base structure.  Because the functions are not
allowed in the low-order 4096 bytes of kernel virtual memory, offsets
up to 4095 bytes can be accommodated.  If the offset is larger than
4095 bytes, a compile-time error will be generated in __kfree_rcu().
If this error is triggered, you can either fall back to use of call_rcu()
or rearrange the structure to position the rcu_head structure into the
first 4096 bytes.

Note that the allowable offset might decrease in the future, for example,
to allow something like kmem_cache_free_rcu().

The new kfree_rcu() function can replace code as follows:

	call_rcu(&p->rcu, simple_kfree_callback);

where "simple_kfree_callback()" might be defined as follows:

	void simple_kfree_callback(struct rcu_head *p)
	{
		struct foo *q = container_of(p, struct foo, rcu);

		kfree(q);
	}

with the following:

	kfree_rcu(&p->rcu, rcu);

Note that the "rcu" is the name of a field in the structure being
freed.  The reason for using this rather than passing in a pointer
to the base structure is that the above approach allows better type
checking.

This commit is based on earlier work by Lai Jiangshan and Manfred Spraul:

Lai's V1 patch: http://lkml.org/lkml/2008/9/18/1
Manfred's patch: http://lkml.org/lkml/2009/1/2/115

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:59 -07:00
Paul E. McKenney 6cc68793e3 rcu: fix spelling
The "preemptible" spelling is preferable.  May as well fix it.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:59 -07:00
Lai Jiangshan 13491a0ee1 rcu: call __rcu_read_unlock() in exit_rcu for tree RCU
Using __rcu_read_lock() in place of rcu_read_lock() leaves any debug
state as it really should be, namely with the lock still held.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:58 -07:00
Paul E. McKenney 7e8b4c7234 rcu: Converge TINY_RCU expedited and normal boosting
This applies a trick from TREE_RCU boosting to TINY_RCU, eliminating
code and adding comments.  The key point is that it is possible for
the booster thread itself to work out whether there is a normal or
expedited boost required based solely on local information.  There
is therefore no need for boost initiation to know or care what type
of boosting is required.  In addition, when boosting is complete for
a given grace period, then by definition there cannot be any more
boosting for that grace period.  This allows eliminating yet more
state and statistics.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:58 -07:00
Paul E. McKenney 203373c81b rcu: remove useless ->boosted_this_gp field
The ->boosted_this_gp field is a holdover from an earlier design that
was to carry out multiple boost operations in parallel.  It is not required
by the current design, which boosts one task at a time.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-05 23:16:58 -07:00
Paul E. McKenney ddeb75814f rcu: code cleanups in TINY_RCU priority boosting.
Extraneous semicolon, bad comment, and fold INIT_LIST_HEAD() into
list_del() to get list_del_init().

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:58 -07:00
Paul E. McKenney f0a07aeaf8 rcu: Switch to this_cpu() primitives
This removes a couple of lines from invoke_rcu_cpu_kthread(), improving
readability.

Reported-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:57 -07:00
Paul E. McKenney 108aae2233 rcu: Use WARN_ON_ONCE for DEBUG_OBJECTS_RCU_HEAD warnings
Avoid additional multiple-warning confusion in memory-corruption scenarios.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:57 -07:00
Paul E. McKenney 561190e3b3 rcu: mark rcutorture boosting callback as being on-stack
The CONFIG_DEBUG_OBJECTS_RCU_HEAD facility requires that on-stack RCU
callbacks be flagged explicitly to debug-objects using the
init_rcu_head_on_stack() and destroy_rcu_head_on_stack() functions.
This commit applies those functions to the rcutorture code that tests
RCU priority boosting.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:57 -07:00
Mathieu Desnoyers fc2ecf7ec7 rcu: Enable DEBUG_OBJECTS_RCU_HEAD from !PREEMPT
The prohibition of DEBUG_OBJECTS_RCU_HEAD from !PREEMPT was due to the
fixup actions.  So just produce a warning from !PREEMPT.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:57 -07:00
Paul E. McKenney 5ece5bab3e rcu: Add forward-progress diagnostic for per-CPU kthreads
Increment a per-CPU counter on each pass through rcu_cpu_kthread()'s
service loop, and add it to the rcudata trace output.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:57 -07:00
Paul E. McKenney 15ba0ba860 rcu: add grace-period age and more kthread state to tracing
This commit adds the age in jiffies of the current grace period along
with the duration in jiffies of the longest grace period since boot
to the rcu/rcugp debugfs file.  It also adds an additional "O" state
to kthread tracing to differentiate between the kthread waiting due to
having nothing to do on the one hand and waiting due to being on the
wrong CPU on the other hand.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-05 23:16:56 -07:00
Paul E. McKenney a9f4793d89 rcu: fix tracing bug thinko on boost-balk attribution
The rcu_initiate_boost_trace() function mis-attributed refusals to
initiate RCU priority boosting that were in fact due to its not yet
being time to boost.  This patch fixes the faulty comparison.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-05 23:16:56 -07:00
Paul E. McKenney 4a29865689 rcu: make rcutorture version numbers available through debugfs
It is not possible to accurately correlate rcutorture output with that
of debugfs.  This patch therefore adds a debugfs file that prints out
the rcutorture version number, permitting easy correlation.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:56 -07:00
Paul E. McKenney d71df90ead rcu: add tracing for RCU's kthread run states.
Add tracing to help debugging situations when RCU's kthreads are not
running but are supposed to be.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:56 -07:00
Paul E. McKenney 0ac3d136b2 rcu: add callback-queue information to rcudata output
This commit adds an indication of the state of the callback queue using
a string of four characters following the "ql=" integer queue length.
The first character is "N" if there are callbacks that have been
queued that are not yet ready to be handled by the next grace period, or
"." otherwise.  The second character is "R" if there are callbacks queued
that are ready to be handled by the next grace period, or "." otherwise.
The third character is "W" if there are callbacks waiting for the current
grace period, or "." otherwise.  Finally, the fourth character is "D"
if there are callbacks that have been handled by a prior grace period
and are waiting to be invoked, or ".".

Note that callbacks that are in the process of being invoked are
not shown.  These callbacks would have been removed from the rcu_data
structure's list by rcu_do_batch() prior to being executed.  (These
callbacks are also not reflected in the "ql=" total, FWIW.)

Also, document the new callback-queue trace information.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:56 -07:00
Paul E. McKenney 0ea1f2ebeb rcu: Add boosting to TREE_PREEMPT_RCU tracing
Includes total number of tasks boosted, number boosted on behalf of each
of normal and expedited grace periods, and statistics on attempts to
initiate boosting that failed for various reasons.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:55 -07:00
Paul E. McKenney 67b98dba47 rcu: eliminate unused boosting statistics
The n_rcu_torture_boost_allocerror and n_rcu_torture_boost_afferror
statistics are not actually incremented anymore, so eliminate them.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:55 -07:00
Paul E. McKenney 3acf4a9a3d rcu: avoid hammering sched with yet another bound RT kthread
The scheduler does not appear to take kindly to having multiple
real-time threads bound to a CPU that is going offline.  So this
commit is a temporary hack-around to avoid that happening.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-05 23:16:55 -07:00
Paul E. McKenney e3995a25fa rcu: put per-CPU kthread at non-RT priority during CPU hotplug operations
If you are doing CPU hotplug operations, it is best not to have
CPU-bound realtime tasks running CPU-bound on the outgoing CPU.
So this commit makes per-CPU kthreads run at non-realtime priority
during that time.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:55 -07:00
Paul E. McKenney 0f962a5e72 rcu: Force per-rcu_node kthreads off of the outgoing CPU
The scheduler has had some heartburn in the past when too many real-time
kthreads were affinitied to the outgoing CPU.  So, this commit lightens
the load by forcing the per-rcu_node and the boost kthreads off of the
outgoing CPU.  Note that RCU's per-CPU kthread remains on the outgoing
CPU until the bitter end, as it must in order to preserve correctness.

Also avoid disabling hardirqs across calls to set_cpus_allowed_ptr(),
given that this function can block.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-05 23:16:55 -07:00
Paul E. McKenney 27f4d28057 rcu: priority boosting for TREE_PREEMPT_RCU
Add priority boosting for TREE_PREEMPT_RCU, similar to that for
TINY_PREEMPT_RCU.  This is enabled by the default-off RCU_BOOST
kernel parameter.  The priority to which to boost preempted
RCU readers is controlled by the RCU_BOOST_PRIO kernel parameter
(defaulting to real-time priority 1) and the time to wait before
boosting the readers who are blocking a given grace period is
controlled by the RCU_BOOST_DELAY kernel parameter (defaulting to
500 milliseconds).

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:55 -07:00
Paul E. McKenney a26ac2455f rcu: move TREE_RCU from softirq to kthread
If RCU priority boosting is to be meaningful, callback invocation must
be boosted in addition to preempted RCU readers.  Otherwise, in presence
of CPU real-time threads, the grace period ends, but the callbacks don't
get invoked.  If the callbacks don't get invoked, the associated memory
doesn't get freed, so the system is still subject to OOM.

But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit
moves the callback invocations to a kthread, which can be boosted easily.

Also add comments and properly synchronized all accesses to
rcu_cpu_kthread_task, as suggested by Lai Jiangshan.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:54 -07:00
Paul E. McKenney 12f5f524ca rcu: merge TREE_PREEPT_RCU blocked_tasks[] lists
Combine the current TREE_PREEMPT_RCU ->blocked_tasks[] lists in the
rcu_node structure into a single ->blkd_tasks list with ->gp_tasks
and ->exp_tasks tail pointers.  This is in preparation for RCU priority
boosting, which will add a third dimension to the combinatorial explosion
in the ->blocked_tasks[] case, but simply a third pointer in the new
->blkd_tasks case.

Also update documentation to reflect blocked_tasks[] merge

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:54 -07:00
Paul E. McKenney e59fb3120b rcu: Decrease memory-barrier usage based on semi-formal proof
Commit d09b62d fixed grace-period synchronization, but left some smp_mb()
invocations in rcu_process_callbacks() that are no longer needed, but
sheer paranoia prevented them from being removed.  This commit removes
them and provides a proof of correctness in their absence.  It also adds
a memory barrier to rcu_report_qs_rsp() immediately before the update to
rsp->completed in order to handle the theoretical possibility that the
compiler or CPU might move massive quantities of code into a lock-based
critical section.  This also proves that the sheer paranoia was not
entirely unjustified, at least from a theoretical point of view.

In addition, the old dyntick-idle synchronization depended on the fact
that grace periods were many milliseconds in duration, so that it could
be assumed that no dyntick-idle CPU could reorder a memory reference
across an entire grace period.  Unfortunately for this design, the
addition of expedited grace periods breaks this assumption, which has
the unfortunate side-effect of requiring atomic operations in the
functions that track dyntick-idle state for RCU.  (There is some hope
that the algorithms used in user-level RCU might be applied here, but
some work is required to handle the NMIs that user-space applications
can happily ignore.  For the short term, better safe than sorry.)

This proof assumes that neither compiler nor CPU will allow a lock
acquisition and release to be reordered, as doing so can result in
deadlock.  The proof is as follows:

1.	A given CPU declares a quiescent state under the protection of
	its leaf rcu_node's lock.

2.	If there is more than one level of rcu_node hierarchy, the
	last CPU to declare a quiescent state will also acquire the
	->lock of the next rcu_node up in the hierarchy,  but only
	after releasing the lower level's lock.  The acquisition of this
	lock clearly cannot occur prior to the acquisition of the leaf
	node's lock.

3.	Step 2 repeats until we reach the root rcu_node structure.
	Please note again that only one lock is held at a time through
	this process.  The acquisition of the root rcu_node's ->lock
	must occur after the release of that of the leaf rcu_node.

4.	At this point, we set the ->completed field in the rcu_state
	structure in rcu_report_qs_rsp().  However, if the rcu_node
	hierarchy contains only one rcu_node, then in theory the code
	preceding the quiescent state could leak into the critical
	section.  We therefore precede the update of ->completed with a
	memory barrier.  All CPUs will therefore agree that any updates
	preceding any report of a quiescent state will have happened
	before the update of ->completed.

5.	Regardless of whether a new grace period is needed, rcu_start_gp()
	will propagate the new value of ->completed to all of the leaf
	rcu_node structures, under the protection of each rcu_node's ->lock.
	If a new grace period is needed immediately, this propagation
	will occur in the same critical section that ->completed was
	set in, but courtesy of the memory barrier in #4 above, is still
	seen to follow any pre-quiescent-state activity.

6.	When a given CPU invokes __rcu_process_gp_end(), it becomes
	aware of the end of the old grace period and therefore makes
	any RCU callbacks that were waiting on that grace period eligible
	for invocation.

	If this CPU is the same one that detected the end of the grace
	period, and if there is but a single rcu_node in the hierarchy,
	we will still be in the single critical section.  In this case,
	the memory barrier in step #4 guarantees that all callbacks will
	be seen to execute after each CPU's quiescent state.

	On the other hand, if this is a different CPU, it will acquire
	the leaf rcu_node's ->lock, and will again be serialized after
	each CPU's quiescent state for the old grace period.

On the strength of this proof, this commit therefore removes the memory
barriers from rcu_process_callbacks() and adds one to rcu_report_qs_rsp().
The effect is to reduce the number of memory barriers by one and to
reduce the frequency of execution from about once per scheduling tick
per CPU to once per grace period.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:54 -07:00
Paul E. McKenney a00e0d714f rcu: Remove conditional compilation for RCU CPU stall warnings
The RCU CPU stall warnings can now be controlled using the
rcu_cpu_stall_suppress boot-time parameter or via the same parameter
from sysfs.  There is therefore no longer any reason to have
kernel config parameters for this feature.  This commit therefore
removes the RCU_CPU_STALL_DETECTOR and RCU_CPU_STALL_DETECTOR_RUNNABLE
kernel config parameters.  The RCU_CPU_STALL_TIMEOUT parameter remains
to allow the timeout to be tuned and the RCU_CPU_STALL_VERBOSE parameter
remains to allow task-stall information to be suppressed if desired.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-05-05 23:16:54 -07:00
Ingo Molnar 4d70230bb4 Merge branch 'master' of ssh://master.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into perf/urgent 2011-05-06 08:11:28 +02:00
Anton Blanchard 228e548e60 net: Add sendmmsg socket system call
This patch adds a multiple message send syscall and is the send
version of the existing recvmmsg syscall. This is heavily
based on the patch by Arnaldo that added recvmmsg.

I wrote a microbenchmark to test the performance gains of using
this new syscall:

http://ozlabs.org/~anton/junkcode/sendmmsg_test.c

The test was run on a ppc64 box with a 10 Gbit network card. The
benchmark can send both UDP and RAW ethernet packets.

64B UDP

batch   pkts/sec
1       804570
2       872800 (+ 8 %)
4       916556 (+14 %)
8       939712 (+17 %)
16      952688 (+18 %)
32      956448 (+19 %)
64      964800 (+20 %)

64B raw socket

batch   pkts/sec
1       1201449
2       1350028 (+12 %)
4       1461416 (+22 %)
8       1513080 (+26 %)
16      1541216 (+28 %)
32      1553440 (+29 %)
64      1557888 (+30 %)

We see a 20% improvement in throughput on UDP send and 30%
on raw socket send.

[ Add sparc syscall entries. -DaveM ]

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-05 11:10:14 -07:00
Andi Kleen 7372b0b122 clockevents: Move C3 stop test outside lock
Avoid taking broadcast_lock in the idle path for systems where the
timer doesn't stop in C3.

[ tglx: Removed the stale label and added comment ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Dave Kleikamp <dkleikamp@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: lenb@kernel.org
Cc: paulmck@us.ibm.com
Link: http://lkml.kernel.org/r/%3C20110504234806.GF2925%40one.firstfloor.org%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-05 17:32:13 +02:00
john stultz e05b2efb82 clocksource: Install completely before selecting
Christian Hoffmann reported that the command line clocksource override
with acpi_pm timer fails:

 Kernel command line: <SNIP> clocksource=acpi_pm
 hpet clockevent registered
 Switching to clocksource hpet
 Override clocksource acpi_pm is not HRT compatible.
 Cannot switch while in HRT/NOHZ mode.

The watchdog code is what enables CLOCK_SOURCE_VALID_FOR_HRES, but we
actually end up selecting the clocksource before we enqueue it into
the watchdog list, so that's why we see the warning and fail to switch
to acpi_pm timer as requested. That's particularly bad when we want to
debug timekeeping related problems in early boot.

Put the selection call last.

Reported-by: Christian Hoffmann <email@christianhoffmann.info>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: stable@kernel.org # 32...
Link: http://lkml.kernel.org/r/%3C1304558210.2943.24.camel%40work-vm%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-05 15:23:26 +02:00
Ingo Molnar 98bb318864 Merge branch 'perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/urgent 2011-05-04 20:33:42 +02:00
Vladimir Davydov 931aeeda0d sched: Remove unused 'this_best_prio arg' from balance_tasks()
It's passed across multiple functions but is never really used, so
remove it.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1304447467-29200-1-git-send-email-vdavydov@parallels.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-04 09:07:21 +02:00
Ingo Molnar e7e7ee2eab perf events: Clean up definitions and initializers, update copyrights
Fix a few inconsistent style bits that were added over the past few
months.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-yv4hwf9yhnzoada8pcpb3a97@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-04 08:49:24 +02:00
Thomas Gleixner 179eb03268 alarmtimer: Drop device refcount after rtc_open()
class_find_device() takes a refcount on the rtc device. rtc_open()
takes another one, so we can drop it after the rtc_open() call.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
2011-05-04 08:18:34 +02:00
Thomas Gleixner ce788f930b alarmtimer: Check return value of class_find_device()
alarmtimer_late_init() uses class_find_device() to find a alarm
capable rtc device. The match callback stores a pointer to the name in
the char pointer handed in from the call site. alarmtimer_late_init()
checks the char pointer for NULL, but the pointer is on the stack and
not initialized to NULL before the call. So it can have random content
when the match function did not identify a device, which leads to
random access in the following rtc_open() call where the pointer is
dereferenced

Instead of relying on the char pointer, check the return value of
class_find_device. If a device is found then the name pointer is valid
as well.

Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-04 08:18:17 +02:00
Borislav Petkov 48dbb6dc86 hw breakpoints: Move to kernel/events/
As part of the events sybsystem unification, relocate hw_breakpoint.c
into its new destination.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-05-03 15:26:43 +02:00
Borislav Petkov fae85b7c8b perf: Start the restructuring
mv kernel/perf_event.c -> kernel/events/core.c. From there, all further
sensible splitting can happen. The idea is that due to perf_event.c
becoming pretty sizable and with the advent of the marriage with ftrace,
splitting functionality into its logical parts should help speeding up
the unification and to manage the complexity of the subsystem.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-05-03 12:59:43 +02:00
Thomas Gleixner 99ee5315da timerfd: Allow timers to be cancelled when clock was set
Some applications must be aware of clock realtime being set
backward. A simple example is a clock applet which arms a timer for
the next minute display. If clock realtime is set backward then the
applet displays a stale time for the amount of time which the clock
was set backwards. Due to that applications poll the time because we
don't have an interface.

Extend the timerfd interface by adding a flag which puts the timer
onto a different internal realtime clock. All timers on this clock are
expired whenever the clock was set.

The timerfd core records the monotonic offset when the timer is
created. When the timer is armed, then the current offset is compared
to the previous recorded offset. When it has changed, then
timerfd_settime returns -ECANCELED. When a timer is read the offset is
compared and if it changed -ECANCELED returned to user space. Periodic
timers are not rearmed in the cancelation case.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Chris Friesen <chris.friesen@genband.com>
Tested-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Reviewed-by: Alexander Shishkin <virtuoso@slind.org>
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104271359580.3323%40ionos%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02 21:39:15 +02:00
Thomas Gleixner b12a03ce48 hrtimers: Prepare for cancel on clock was set timers
Make clock_was_set() unconditional and rename hres_timers_resume to
hrtimers_resume. This is a preparatory patch for hrtimers which are
cancelled when clock realtime was set.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02 21:37:58 +02:00
Mike Frysinger 942c3c5c32 hrtimer: Make lookup table const
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Link: http://lkml.kernel.org/r/%3C1304364267-14489-1-git-send-email-vapier%40gentoo.org%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02 21:37:57 +02:00
Thomas Gleixner 3687a2c0d8 Merge branch 'linus' into timers/core
Reason: Pick up the hrtimer_clock_to_base_table fix from mainline

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02 21:37:08 +02:00
John Stultz 472647dcd7 timers: Fix alarmtimer build issues when CONFIG_RTC_CLASS=n
Ingo pointed out that the alarmtimers won't build if CONFIG_RTC_CLASS=n.
This patch adds proper ifdefs to the alarmtimer code to disable the rtc
usage if it is not built in.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02 21:36:57 +02:00
Geert Uytterhoeven 94b2c363dc genirq: Fix typo CONFIG_GENIRC_IRQ_SHOW_LEVEL
commit ab7798ffcf ("genirq: Expand generic
show_interrupts()") added the Kconfig option GENERIC_IRQ_SHOW_LEVEL to
accomodate PowerPC, but this doesn't actually enable the functionality due
to a typo in the #ifdef check.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linux/PPC Development <linuxppc-dev@lists.ozlabs.org>
Link: http://lkml.kernel.org/r/%3Calpine.DEB.2.00.1104302251370.19068%40ayla.of.borg%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02 21:16:37 +02:00
Thomas Gleixner c42321c76b genirq: Make generic irq chip depend on CONFIG_GENERIC_IRQ_CHIP
Only compile it in when there are users.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
2011-05-02 18:16:22 +02:00
Ingo Molnar ac0a3260f3 Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core 2011-05-01 19:11:42 +02:00
Ingo Molnar 809435ff4f Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core 2011-05-01 19:09:39 +02:00
Linus Torvalds 3fd9952df4 Merge branch 'fixes-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
* 'fixes-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix deadlock in worker_maybe_bind_and_lock()
  workqueue: Document debugging tricks

Fix up trivial spelling conflict in kernel/workqueue.c
2011-04-30 09:15:40 -07:00
Steven Rostedt b9df92d2a9 ftrace: Consolidate the function match routines for normal and mods
The code used for matching functions is almost identical between normal
selecting of functions and using the :mod: feature of set_ftrace_notrace.

Consolidate the two users into one function.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:53:14 -04:00
Steven Rostedt 491d0dcfb9 ftrace: Consolidate updating of ftrace_trace_function
There are three locations that perform almost identical functions in order
to update the ftrace_trace_function (the ftrace function variable that gets
called by mcount).

Consolidate these into a single function called update_ftrace_function().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:53:11 -04:00
Steven Rostedt 996e87be7f ftrace: Move record update for normal and modules into a separate function
The updating of a function record is moved to a single function. This will allow
us to add specific changes in one location for both modules and kernel
functions.

Later patches will determine if the function record itself needs to be updated
(which enables the mcount caller), or just the ftrace_ops needs the update.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:53:08 -04:00
Steven Rostedt d2c8c3eafb ftrace: Remove FTRACE_FL_CONVERTED flag
Since we disable all function tracer processing if we detect
that a modification of a instruction had failed, we do not need
to track that the record has failed. No more ftrace processing
is allowed, and the FTRACE_FL_CONVERTED flag is pointless.

The FTRACE_FL_CONVERTED flag was used to denote records that were
successfully converted from mcount calls into nops. But if a single
record fails, all of ftrace is disabled.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:53:04 -04:00
Steven Rostedt 45a4a2372b ftrace: Remove FTRACE_FL_FAILED flag
Since we disable all function tracer processing if we detect
that a modification of a instruction had failed, we do not need
to track that the record has failed. No more ftrace processing
is allowed, and the FTRACE_FL_FAILED flag is pointless.

Removing this flag simplifies some of the code, but some ftrace_disabled
checks needed to be added or move around a little.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:53:01 -04:00
Steven Rostedt 3499e46114 ftrace: Remove failures file
The failures file in the debugfs tracing directory would list the
functions that failed to convert when the old dead ftrace daemon
tried to update code but failed. Since this code is now dead along
with the daemon the failures file is useless. Remove it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:52:58 -04:00
Steven Rostedt 8ab2b7efd3 ftrace: Remove unnecessary disabling of irqs
The disabling of interrupts around ftrace_update_code() was used
to protect against the evil ftrace daemon from years past. But that
daemon has long been killed. It is safe to keep interrupts enabled
while updating the initial mcount into nops.

The ftrace_mutex is also held which keeps other users at bay.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:52:55 -04:00
Steven Rostedt 0778d9ad33 ftrace: Make FTRACE_WARN_ON() work in if condition
Let FTRACE_WARN_ON() be used as a stand alone statement or
inside a conditional: if (FTRACE_WARN_ON(x))

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:52:52 -04:00
Steven Rostedt 058e297d34 ftrace: Only update the function code on write to filter files
If function tracing is enabled, a read of the filter files will
cause the call to stop_machine to update the function trace sites.
It should only call stop_machine on write.

Cc: stable@kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29 22:42:59 -04:00
Rafael J. Wysocki 85eb8c8d0b PM / Runtime: Generic clock manipulation rountines for runtime PM (v6)
Many different platforms and subsystems may want to disable device
clocks during suspend and enable them during resume which is going to
be done in a very similar way in all those cases.  For this reason,
provide generic routines for the manipulation of device clocks during
suspend and resume.

Convert the ARM shmobile platform to using the new routines.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-04-30 00:25:44 +02:00
Linus Torvalds 40a963502c Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf, x86, nmi: Move LVT un-masking into irq handlers
  perf events, x86: Work around the Nehalem AAJ80 erratum
  perf, x86: Fix BTS condition
  ftrace: Build without frame pointers on Microblaze
2011-04-29 15:08:53 -07:00
Linus Torvalds fcc4dc7151 Merge branch 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  hrtimer: Initialize CLOCK_ID to HRTIMER_BASE table statically
  rtc: max8925: Call dev_set_drvdata before rtc_device_register
2011-04-29 15:08:31 -07:00
Tejun Heo 5035b20fa5 workqueue: fix deadlock in worker_maybe_bind_and_lock()
If a rescuer and stop_machine() bringing down a CPU race with each
other, they may deadlock on non-preemptive kernel.  The CPU won't
accept a new task, so the rescuer can't migrate to the target CPU,
while stop_machine() can't proceed because the rescuer is holding one
of the CPU retrying migration.  GCWQ_DISASSOCIATED is never cleared
and worker_maybe_bind_and_lock() retries indefinitely.

This problem can be reproduced semi reliably while the system is
entering suspend.

 http://thread.gmane.org/gmane.linux.kernel/1122051

A lot of kudos to Thilo-Alexander for reporting this tricky issue and
painstaking testing.

stable: This affects all kernels with cmwq, so all kernels since and
        including v2.6.36 need this fix.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Thilo-Alexander Ginkel <thilo@ginkel.com>
Tested-by: Thilo-Alexander Ginkel <thilo@ginkel.com>
Cc: stable@kernel.org
2011-04-29 18:08:37 +02:00
Thomas Gleixner ce31332d3c hrtimer: Initialize CLOCK_ID to HRTIMER_BASE table statically
Sedat and Bruno reported RCU stalls which turned out to be caused by
the following;

sched_init() calls init_rt_bandwidth() which calls hrtimer_init()
_BEFORE_ hrtimers_init() is called. While not entirely correct this
worked because hrtimer_init() only accessed statically initialized
data (hrtimer_bases.clock_base[CLOCK_MONOTONIC])

Commit e06383db9 (hrtimers: extend hrtimer base code to handle more
then 2 clockids) added an indirection to the hrtimer_bases.clock_base
lookup to avoid gap handling in the hot path. The table which is used
for the translataion from CLOCK_ID to HRTIMER_BASE index is
initialized at runtime in hrtimers_init(). So the early call of the
scheduler code translates CLOCK_MONOTONIC to HRTIMER_BASE_REALTIME.

Thus the rt_bandwith timer ends up on CLOCK_REALTIME. If the timer is
armed and the wall clock time is set (e.g. ntpdate in the early boot
process - which also gives the problem deterministic behaviour
i.e. magic recovery after N hours), then the timer ends up with an
expiry time far into the future. That breaks the RT throttler
mechanism as rt runtime is accumulated and never cleared, so the rt
throttler detects a false cpu hog condition and blocks all RT tasks
until the timer finally expires. That in turn stalls the RCU thread of
TINYRCU which leads to an huge amount of RCU callbacks piling up.

Make the translation table statically initialized, so we are back to
the status of <= 2.6.39.

Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reported-by: Bruno Prémont <bonbons@linux-vserver.org>
Cc: John stultz <johnstul@us.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104282353140.3005%40ionos%3E
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-29 10:57:11 +02:00
John Stultz 7068b7a162 timers: Remove delayed irqwork from alarmtimers implementation
Thomas asked about the delayed irq work in the alarmtimers code,
and I realized that it was a legacy from when the alarmtimer base
lock was a mutex (due to concerns that we'd be interacting with
the RTC device, which is protected by mutexes).

Since the alarmtimer base is now protected by a spinlock, we can
simply execute alarmtimer functions directly from the hrtimer
callback. Should any future alarmtimer functions sleep, they can
simply manage scheduling any delayed work themselves.

CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-28 13:39:18 -07:00
John Stultz 180bf812ce timers: Improve alarmtimer comments and minor fixes
This patch addresses a number of minor comment improvements and
other minor issues from Thomas' review of the alarmtimers code.

CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-28 13:39:17 -07:00
Hillf Danton 1409f141ac kernel/watchdog.c: disable nmi perf event in the error path of enabling watchdog
In corner cases where softlockup watchdog is not setup successfully, the
relevant nmi perf event for hardlockup watchdog could be disabled, then
the status of the underlying hardware remains unchanged.

Also, if the kthread doesn't start then the hrtimer won't run and the
hardlockup detector will falsely fire.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-28 11:28:21 -07:00
Oleg Nesterov b013c39924 signal: cleanup sys_sigprocmask()
Cleanup. Remove the unneeded goto's, we can simply read blocked.sig[0]
unconditionally and then copy-to-user it if oset != NULL.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
2011-04-28 13:01:40 +02:00
Oleg Nesterov 702a5073fd signal: rename signandsets() to sigandnsets()
As Tejun and Linus pointed out, "nand" is the wrong name for "x & ~y",
it should be "andn". Rename signandsets() as suggested.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28 13:01:39 +02:00
Oleg Nesterov b182801ab3 signal: do_sigtimedwait() needs retarget_shared_pending()
do_sigtimedwait() changes current->blocked and thus it needs
set_current_blocked()->retarget_shared_pending().

We could use set_current_blocked() directly. It is fine to change
->real_blocked from all-zeroes to ->blocked and vice versa lockless,
but this is not immediately clear, looks racy, and needs a huge
comment to explain why this is correct.

To keep the things simple this patch adds the new static helper,
__set_task_blocked() which should be called with ->siglock held. This
way we can change both ->real_blocked and ->blocked atomically under
->siglock as the current code does. This is more understandable.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
2011-04-28 13:01:39 +02:00
Oleg Nesterov 943df1485a signal: introduce do_sigtimedwait() to factor out compat/native code
Factor out the common code in sys_rt_sigtimedwait/compat_sys_rt_sigtimedwait
to the new helper, do_sigtimedwait().

Add the comment to document the extra tick we add to timespec_to_jiffies(ts),
thanks to Linus who explained this to me.

Perhaps it would be better to move compat_sys_rt_sigtimedwait() into
signal.c under CONFIG_COMPAT, then we can make do_sigtimedwait() static.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
2011-04-28 13:01:38 +02:00
Oleg Nesterov fe0faa005d signal: sys_rt_sigtimedwait: simplify the timeout logic
No functional changes, cleanup compat_sys_rt_sigtimedwait() and
sys_rt_sigtimedwait().

Calculate the timeout before we take ->siglock, this simplifies and
lessens the code. Use timespec_valid() to check the timespec.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
2011-04-28 13:01:38 +02:00
Oleg Nesterov bb7efee2ca signal: cleanup sys_rt_sigprocmask()
sys_rt_sigprocmask() looks unnecessarily complicated, simplify it.
We can just read current->blocked lockless unconditionally before
anything else and then copy-to-user it if needed.  At worst we
copy 4 words on mips.

We could copy-to-user the old mask first and simplify the code even
more, but the patch tries to keep the current behaviour: we change
current->block even if copy_to_user(oset) fails.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28 13:01:38 +02:00
Oleg Nesterov e6fa16ab9c signal: sigprocmask() should do retarget_shared_pending()
In short, almost every changing of current->blocked is wrong, or at least
can lead to the unexpected results.

For example. Two threads T1 and T2, T1 sleeps in sigtimedwait/pause/etc.
kill(tgid, SIG) can pick T2 for TIF_SIGPENDING. If T2 calls sigprocmask()
and blocks SIG before it notices the pending signal, nobody else can handle
this pending shared signal.

I am not sure this is bug, but at least this looks strange imho. T1 should
not sleep forever, there is a signal which should wake it up.

This patch moves the code which actually changes ->blocked into the new
helper, set_current_blocked() and changes this code to call
retarget_shared_pending() as exit_signals() does. We should only care about
the signals we just blocked, we use "newset & ~current->blocked" as a mask.

We do not check !sigisemptyset(newblocked), retarget_shared_pending() is
cheap unless mask & shared_pending.

Note: for this particular case we could simply change sigprocmask() to
return -EINTR if signal_pending(), but then we should change other callers
and, more importantly, if we need this fix then set_current_blocked() will
have more callers and some of them can't restart. See the next patch as a
random example.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28 13:01:37 +02:00
Oleg Nesterov 73ef4aeb61 signal: sigprocmask: narrow the scope of ->siglock
No functional changes, preparation to simplify the review of the next change.

1. We can read current->block lockless, nobody else can ever change this mask.

2. Calculate the resulting sigset_t outside of ->siglock into the temporary
   variable, then take ->siglock and change ->blocked.

Also, kill the stale comment about BKL.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28 13:01:36 +02:00
Oleg Nesterov fec9993db0 signal: retarget_shared_pending: optimize while_each_thread() loop
retarget_shared_pending() blindly does recalc_sigpending_and_wake() for
every sub-thread, this is suboptimal. We can check t->blocked and stop
looping once every bit in shared_pending has the new target.

Note: we do not take task_is_stopped_or_traced(t) into account, we are
not trying to speed up the signal delivery or to avoid the unnecessary
(but harmless) signal_wake_up(0) in this unlikely case.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28 13:01:35 +02:00
Oleg Nesterov f646e227b8 signal: retarget_shared_pending: consider shared/unblocked signals only
exit_signals() checks signal_pending() before retarget_shared_pending() but
this is suboptimal. We can avoid the while_each_thread() loop in case when
there are no shared signals visible to us.

Add the "shared_pending.signal & ~blocked" check. We don't use tsk->blocked
directly but pass ~blocked as an argument, this is needed for the next patch.

Note: we can optimize this more. while_each_thread(t) can check t->blocked
into account and stop after every pending signal has the new target, see the
next patch.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28 13:01:35 +02:00
Oleg Nesterov 0edceb7bcd signal: introduce retarget_shared_pending()
No functional changes. Move the notify-other-threads code from exit_signals()
to the new helper, retarget_shared_pending().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28 13:01:35 +02:00
Jeff Mahoney e11feaa119 watchdog, hung_task_timeout: Add Kconfig configurable default
This patch allows the default value for sysctl_hung_task_timeout_secs
to be set at build time. The feature carries virtually no overhead,
so it makes sense to keep it enabled. On heavily loaded systems, though,
it can end up triggering stack traces when there is no bug other than
the system being underprovisioned. We use this patch to keep the hung task
facility available but disabled at boot-time.

The default of 120 seconds is preserved. As a note, commit e162b39a may
have accidentally reverted commit fb822db4, which raised the default from
120 seconds to 480 seconds.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Mandeep Singh Baines <msb@google.com>
Link: http://lkml.kernel.org/r/4DB8600C.8080000@suse.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-28 09:13:17 +02:00
Tony Jones f562988350 audit: acquire creds selectively to reduce atomic op overhead
Commit c69e8d9c01 ("CRED: Use RCU to access another task's creds and to
release a task's own creds") added calls to get_task_cred and put_cred in
audit_filter_rules.  Profiling with a large number of audit rules active
on the exit chain shows that we are spending upto 48% in this routine for
syscall intensive tests, most of which is in the atomic ops.

1. The code should be accessing tsk->cred rather than tsk->real_cred.
2. Since tsk is current (or tsk is being created by copy_process) access to
tsk->cred without rcu read lock is possible.  At the request of the audit
maintainer, a new flag has been added to audit_filter_rules in order to make
this explicit and guide future code.

Signed-off-by: Tony Jones <tonyj@suse.de>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-27 15:11:03 +02:00
Ingo Molnar 32673822e4 Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
Conflicts:
	include/linux/perf_event.h

Merge reason: pick up the latest jump-label enhancements, they are cooked ready.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-27 10:40:21 +02:00
Ingo Molnar 6c8a721327 Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/urgent 2011-04-27 10:31:29 +02:00
John Stultz 9a7adcf5c6 timers: Posix interface for alarm-timers
This patch exposes alarm-timers to userland via the posix clock
and timers interface, using two new clockids: CLOCK_REALTIME_ALARM
and CLOCK_BOOTTIME_ALARM. Both clockids behave identically to
CLOCK_REALTIME and CLOCK_BOOTTIME, respectively, but timers
set against the _ALARM suffixed clockids will wake the system if
it is suspended.

Some background can be found here:
	https://lwn.net/Articles/429925/

The concept for Alarm-timers was inspired by the Android Alarm
driver (by Arve Hjønnevåg) found in the Android kernel tree.

See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36

While the in-kernel interface is pretty similar between
alarm-timers and Android alarm driver, the user-space interface
for the Android alarm driver is via ioctls to a new char device.
As mentioned above, I've instead chosen to export this functionality
via the posix interface, as it seemed a little simpler and avoids
creating duplicate interfaces to things like CLOCK_REALTIME and
CLOCK_MONOTONIC under alternate names (ie:ANDROID_ALARM_RTC and
ANDROID_ALARM_SYSTEMTIME).

The semantics of the Android alarm driver are different from what
this posix interface provides. For instance, threads other then
the thread waiting on the Android alarm driver are able to modify
the alarm being waited on. Also this interface does not allow
the same wakelock semantics that the Android driver provides
(ie: kernel takes a wakelock on RTC alarm-interupt, and holds it
through process wakeup, and while the process runs, until the
process either closes the char device or calls back in to wait
on a new alarm).

One potential way to implement similar semantics may be via
the timerfd infrastructure, but this needs more research.

There may also need to be some sort of sysfs system level policy
hooks that allow alarm timers to be disabled to keep them
from firing at inappropriate times (ie: laptop in a well insulated
bag, mid-flight).

CC: Arve Hjønnevåg <arve@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-26 14:01:46 -07:00
John Stultz ff3ead96d1 timers: Introduce in-kernel alarm-timer interface
This provides the in kernel interface and infrastructure for
alarm-timers.

Alarm-timers are a hybrid style timer, similar to hrtimers,
but when the system is suspended, the RTC device is set to
fire and wake the system for when the soonest alarm-timer
expires.

The concept for Alarm-timers was inspired by the Android Alarm
driver (by Arve Hjønnevåg) found in the Android kernel tree.

See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36

This in-kernel interface should be fairly compatible with the
Android alarm driver in-kernel interface, but has the advantage
of utilizing the new RTC timerqueue code instead of doing direct
RTC manipulation.

CC: Arve Hjønnevåg <arve@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-26 14:01:44 -07:00
John Stultz 304529b1b6 time: Add timekeeping_inject_sleeptime
Some platforms cannot implement read_persistent_clock, as
their RTC devices are only accessible when interrupts are enabled.
This keeps them from being used by the timekeeping code on resume
to measure the time in suspend.

The RTC layer tries to work around this, by calling do_settimeofday
on resume after irqs are reenabled to set the time properly. However,
this only corrects CLOCK_REALTIME, and does not properly adjust
the sleep time value. This causes btime in /proc/stat to be incorrect
as well as making the new CLOCK_BOTTTIME inaccurate.

This patch resolves the issue by introducing a new timekeeping hook
to allow the RTC layer to inject the sleep time on resume.

The code also checks to make sure that read_persistent_clock is
nonfunctional before setting the sleep time, so that should the RTC's
HCTOSYS option be configured in on a system that does support
read_persistent_clock we will not increase the total_sleep_time twice.

CC: Arve Hjønnevåg <arve@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-26 14:01:41 -07:00
Hillf Danton 1437f5bca3 sched: Remove noop in alloc_rt_sched_group()
The rq varible, though computed for each possible cpu, has nothing to
do in the function, so it can be removed.

This also eliminates a build warning.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/BANLkTin-FfQfqW5ym1iuEmrk8s777Y1LAg@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-26 13:34:08 +02:00
Jiri Kosina 07f9479a40 Merge branch 'master' into for-next
Fast-forwarded to current state of Linus' tree as there are patches to be
applied for files that didn't exist on the old branch.
2011-04-26 10:22:59 +02:00
Roland Vossen 7816c45bf1 modules: Enabled dynamic debugging for staging modules
Driver modules from the staging directory are marked 'tainted'
by module.c. Subsequently, tainted modules are denied dynamic
debugging. This is unwanted behavior, since staging modules should
be able to use the dynamic debugging mechanism.

Please merge this also into the staging-linus branch.

Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-25 16:45:22 -07:00
Jonathan Cameron e7e09cd667 params.c: Use new strtobool function to process boolean inputs
No functional changes.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-25 16:04:52 -07:00
Frederic Weisbecker bf26c01849 ptrace: Prepare to fix racy accesses on task breakpoints
When a task is traced and is in a stopped state, the tracer
may execute a ptrace request to examine the tracee state and
get its task struct. Right after, the tracee can be killed
and thus its breakpoints released.
This can happen concurrently when the tracer is in the middle
of reading or modifying these breakpoints, leading to dereferencing
a freed pointer.

Hence, to prepare the fix, create a generic breakpoint reference
holding API. When a reference on the breakpoints of a task is
held, the breakpoints won't be released until the last reference
is dropped. After that, no more ptrace request on the task's
breakpoints can be serviced for the tracer.

Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: v2.6.33.. <stable@kernel.org>
Link: http://lkml.kernel.org/r/1302284067-7860-2-git-send-email-fweisbec@gmail.com
2011-04-25 17:28:24 +02:00
Jonathan Corbet 625f2a378e sched: Get rid of lock_depth
Neil Brown pointed out that lock_depth somehow escaped the BKL
removal work.  Let's get rid of it now.

Note that the perf scripting utilities still have a bunch of
code for dealing with common_lock_depth in tracepoints; I have
left that in place in case anybody wants to use that code with
older kernels.

Suggested-by: Neil Brown <neilb@suse.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110422111910.456c0e84@bike.lwn.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-24 13:18:38 +02:00
Linus Torvalds 686c4cbb10 Merge branch 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  PM: Add missing syscore_suspend() and syscore_resume() calls
  PM: Fix error code paths executed after failing syscore_suspend()
2011-04-23 22:35:16 -07:00
Thomas Gleixner cfefd21e69 genirq: Add chip suspend and resume callbacks
These callbacks are only called in the syscore suspend/resume code on
interrupt chips which have been registered via the generic irq chip
mechanism. Calling those callbacks per irq would be rather icky, but
with the generic irq chip mechanism we can call this per registered
chip.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
2011-04-23 15:56:24 +02:00
Thomas Gleixner 7d82806247 genirq: Implement a generic interrupt chip
Implement a generic interrupt chip, which is configurable and is able
to handle the most common irq chip implementations.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by; Kevin Hilman <khilman@ti.com>
2011-04-23 15:56:24 +02:00
Paul Mundt 7f1b1244e1 genirq: Support per-IRQ thread disabling.
This adds support for disabling threading on a per-IRQ basis via the IRQ
status instead of the IRQ flow, which is necessary for interrupts that
don't follow the natural IRQ flow channels, such as those that are
virtually created.

The new APIs added are simply:

	irq_set_thread()
	irq_set_nothread()

which follow the rest of the IRQ status routines.

Chained handlers also have IRQ_NOTHREAD set on them automatically, making
the lack of threading explicit rather than implicit. Subsequently, the
nothread flag can be viewed through the standard genirq debugging
facilities.

[ tglx: Fixed cleanup fallout ]

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Link: http://lkml.kernel.org/r/%3C20110406210135.GF18426%40linux-sh.org%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-23 15:56:24 +02:00
Steven Rostedt e0944ee63f lockdep: Remove cmpxchg to update nr_chain_hlocks
For some reason nr_chain_hlocks is updated with cmpxchg, but
this is performed inside of the lockdep global "grab_lock()",
which also makes simple modification of this variable atomic.

Remove the cmpxchg logic for updating nr_chain_hlocks and
simplify the code.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110421014300.727863282@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-22 11:06:59 +02:00
Steven Rostedt 282b5c2f6f lockdep: Print a nicer description for simple irq lock inversions
Lockdep output can be pretty cryptic, having nicer output
can save a lot of head scratching. When a simple irq inversion
scenario is detected by lockdep (lock A taken in interrupt
context but also in thread context without disabling interrupts)
we now get the following (hopefully more informative) output:

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(lockA);
  <Interrupt>
    lock(lockA);

 *** DEADLOCK ***

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110421014300.436140880@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-22 11:06:59 +02:00
Steven Rostedt 6be8c3935b lockdep: Replace "Bad BFS generated tree" message with something less cryptic
The message of "Bad BFS generated tree" is a bit confusing.
Replace it with a more sane error message.

Thanks to Peter Zijlstra for helping me come up with a better
message.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110421014300.135521252@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-22 11:06:59 +02:00
Steven Rostedt dad3d7435e lockdep: Print a nicer description for irq inversion bugs
Irq inversion and irq dependency bugs are only subtly
different. The diffenerence lies where the interrupt occurred.

For irq dependency:

	irq_disable
	lock(A)
	lock(B)
	unlock(B)
	unlock(A)
	irq_enable

	lock(B)
	unlock(B)

 	<interrupt>
	  lock(A)

The interrupt comes in after it has been established that lock A
can be held when taking an irq unsafe lock. Lockdep detects the
problem when taking lock A in interrupt context.

With the irq_inversion the irq happens before it is established
and lockdep detects the problem with the taking of lock B:

 	<interrupt>
	  lock(A)

	irq_disable
	lock(A)
	lock(B)
	unlock(B)
	unlock(A)
	irq_enable

	lock(B)
	unlock(B)

Since the problem with the locking logic for both of these issues
is in actuality the same, they both should report the same scenario.
This patch implements that and prints this:

other info that might help us debug this:

Chain exists of:
  &rq->lock --> lockA --> lockC

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(lockC);
                               local_irq_disable();
                               lock(&rq->lock);
                               lock(lockA);
  <Interrupt>
    lock(&rq->lock);

 *** DEADLOCK ***

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110421014259.910720381@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-22 11:06:58 +02:00
Steven Rostedt 48702ecf30 lockdep: Print a nicer description for simple deadlocks
Lockdep output can be pretty cryptic, having nicer output
can save a lot of head scratching. When a simple deadlock
scenario is detected by lockdep (lock A -> lock A) we now
get the following new output:

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(lock)->rlock);
  lock(&(lock)->rlock);

 *** DEADLOCK ***

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110421014259.643930104@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-22 11:06:58 +02:00
Steven Rostedt f4185812aa lockdep: Print a nicer description for normal deadlocks
The lockdep output can be pretty cryptic, having nicer output
can save a lot of head scratching. When a normal deadlock
scenario is detected by lockdep (lock A -> lock B and there
exists a place where lock B -> lock A) we now get the following
new output:

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(lockB);
                               lock(lockA);
                               lock(lockB);
  lock(lockA);

 *** DEADLOCK ***

On cases where there's a deeper chair, it shows the partial
chain that can cause the issue:

Chain exists of:
  lockC --> lockA --> lockB

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(lockB);
                               lock(lockA);
                               lock(lockB);
  lock(lockC);

 *** DEADLOCK ***

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110421014259.380621789@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-22 11:06:57 +02:00
Steven Rostedt 3003eba313 lockdep: Print a nicer description for irq lock inversions
Locking order inversion due to interrupts is a subtle problem.

When an irq lockiinversion discovered by lockdep it currently
reports something like:

[ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ]

... and then prints out the locks that are involved, as back traces.

Judging by lkml feedback developers were routinely confused by what
a HARDIRQ->safe to unsafe issue is all about, and sometimes even
blew it off as a bug in lockdep.

It is not obvious when lockdep prints this message about a lock that
is never taken in interrupt context.

After explaining the problems that lockdep is reporting, I
decided to add a description of the problem in visual form. Now
the following is shown:

 ---
other info that might help us debug this:

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(lockA);
                               local_irq_disable();
                               lock(&rq->lock);
                               lock(lockA);
  <Interrupt>
    lock(&rq->lock);

 *** DEADLOCK ***

 ---

The above is the case when the unsafe lock is taken while
holding a lock taken in irq context. But when a lock is taken
that also grabs a unsafe lock, the call chain is shown:

 ---
other info that might help us debug this:

Chain exists of:
  &rq->lock --> lockA --> lockC

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(lockC);
                               local_irq_disable();
                               lock(&rq->lock);
                               lock(lockA);
  <Interrupt>
    lock(&rq->lock);

 *** DEADLOCK ***

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110421014259.132728798@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-22 11:06:57 +02:00
Michal Simek d20ac25282 ftrace: Build without frame pointers on Microblaze
Microblaze doesn't need/support FRAME_POINTERS in order to have a working
function tracer.

The patch remove Kconfig warning.

Warning log:
warning: (LOCKDEP && FAULT_INJECTION_STACKTRACE_FILTER && LATENCYTOP &&
FUNCTION_TRACER && KMEMCHECK) selects FRAME_POINTER which has unmet direct
dependencies (DEBUG_KERNEL && (CRIS || M68K || FRV || UML || AVR32 ||
SUPERH || BLACKFIN || MN10300) || ARCH_WANT_FRAME_POINTERS)

Signed-off-by: Michal Simek <monstr@monstr.eu>
Link: http://lkml.kernel.org/r/1301908812-8119-2-git-send-email-monstr@monstr.eu
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-21 09:06:24 -04:00
Rakib Mullick d3bf52e998 sched: Remove obsolete comment from scheduler_tick()
scheduler_tick() is no longer called by fork code - this got discarded
a long time ago by commit bc947631d1 ("sched: improve efficiency
of sched_fork()").

So, remove the comment which still claims otherwise.

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/BANLkTimO4iGP0QpaHO1HHF1QOnVcQpc0cw@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-21 11:41:36 +02:00
Ingo Molnar 42ac9e87fd Merge commit 'v2.6.39-rc4' into sched/core
Merge reason: Pick up upstream fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-21 11:39:28 +02:00
Ludwig Nussel 088ab0b4d8 kernel/ksysfs.c: expose file_caps_enabled in sysfs
A kernel booted with no_file_caps allows to install fscaps on a binary
but doesn't actually honor the fscaps when running the binary. Userspace
currently has no sane way to determine whether installing fscaps
actually has any effect. Since parsing /proc/cmdline is fragile this
patch exposes the current setting (1 or 0) via /sys/kernel/fscaps

Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:45:51 -07:00
Rafael J. Wysocki 19234c0819 PM: Add missing syscore_suspend() and syscore_resume() calls
Device suspend/resume infrastructure is used not only by the suspend
and hibernate code in kernel/power, but also by APM, Xen and the
kexec jump feature.  However, commit 40dc166cb5
(PM / Core: Introduce struct syscore_ops for core subsystems PM)
failed to add syscore_suspend() and syscore_resume() calls to that
code, which generally leads to breakage when the features in question
are used.

To fix this problem, add the missing syscore_suspend() and
syscore_resume() calls to arch/x86/kernel/apm_32.c, kernel/kexec.c
and drivers/xen/manage.c.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2011-04-20 00:36:11 +02:00
Linus Torvalds 4ae0ff16ef Merge branch 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  RTC: rtc-omap: Fix a leak of the IRQ during init failure
  posix clocks: Replace mutex with reader/writer semaphore
2011-04-19 10:56:46 -07:00
James Morris d4ab4e6a23 Merge branch 'master'; commit 'v2.6.39-rc3' into next 2011-04-19 21:32:41 +10:00
Peter Zijlstra 057f3fadb3 sched: Fix sched_domain iterations vs. RCU
Vladis Kletnieks reported a new RCU debug warning in the scheduler.

Since commit dce840a087 ("sched: Dynamically allocate sched_domain/
sched_group data-structures") the sched_domain trees are protected by
RCU instead of RCU-sched.

This means that we need to include rcu_read_lock() protection when we
iterate them since disabling preemption doesn't suffice anymore.

Reported-by: Valdis.Kletnieks@vt.edu
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1302882741.2388.241.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-19 10:56:54 +02:00
Venkatesh Pallipadi 2f36825b17 sched: Next buddy hint on sleep and preempt path
When a task in a taskgroup sleeps, pick_next_task starts all the way back at
the root and picks the task/taskgroup with the min vruntime across all
runnable tasks.

But when there are many frequently sleeping tasks across different taskgroups,
it makes better sense to stay with same taskgroup for its slice period (or
until all tasks in the taskgroup sleeps) instead of switching cross taskgroup
on each sleep after a short runtime.

This helps specifically where taskgroups corresponds to a process with
multiple threads. The change reduces the number of CR3 switches in this case.

Example:

Two taskgroups with 2 threads each which are running for 2ms and
sleeping for 1ms. Looking at sched:sched_switch shows:

BEFORE: taskgroup_1 threads [5004, 5005], taskgroup_2 threads [5016, 5017]
      cpu-soaker-5004  [003]  3683.391089
      cpu-soaker-5016  [003]  3683.393106
      cpu-soaker-5005  [003]  3683.395119
      cpu-soaker-5017  [003]  3683.397130
      cpu-soaker-5004  [003]  3683.399143
      cpu-soaker-5016  [003]  3683.401155
      cpu-soaker-5005  [003]  3683.403168
      cpu-soaker-5017  [003]  3683.405170

AFTER: taskgroup_1 threads [21890, 21891], taskgroup_2 threads [21934, 21935]
      cpu-soaker-21890 [003]   865.895494
      cpu-soaker-21935 [003]   865.897506
      cpu-soaker-21934 [003]   865.899520
      cpu-soaker-21935 [003]   865.901532
      cpu-soaker-21934 [003]   865.903543
      cpu-soaker-21935 [003]   865.905546
      cpu-soaker-21891 [003]   865.907548
      cpu-soaker-21890 [003]   865.909560
      cpu-soaker-21891 [003]   865.911571
      cpu-soaker-21890 [003]   865.913582
      cpu-soaker-21891 [003]   865.915594
      cpu-soaker-21934 [003]   865.917606

Similar problem is there when there are multiple taskgroups and say a task A
preempts currently running task B of taskgroup_1. On schedule, pick_next_task
can pick an unrelated task on taskgroup_2. Here it would be better to give some
preference to task B on pick_next_task.

A simple (may be extreme case) benchmark I tried was tbench with 2 tbench
client processes with 2 threads each running on a single CPU. Avg throughput
across 5 50 sec runs was:

 BEFORE: 105.84 MB/sec
 AFTER:  112.42 MB/sec

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1302802253-25760-1-git-send-email-venki@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-19 10:08:38 +02:00
Venkatesh Pallipadi 69c80f3e9d sched: Make set_*_buddy() work on non-task entities
Make set_*_buddy() work on non-task sched_entity, to facilitate the
use of next_buddy to cache a group entity in cases where one of the
tasks within that entity sleeps or gets preempted.

set_skip_buddy() was incorrectly comparing the policy of task that is
yielding to be not equal to SCHED_IDLE. Yielding should happen even
when task yielding is SCHED_IDLE. This change removes the policy check
on the yielding task.

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1302744070-30079-2-git-send-email-venki@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-19 10:08:37 +02:00
Rafael J. Wysocki 2ca6f62f59 PM: Fix error code paths executed after failing syscore_suspend()
If syscore_suspend() fails in suspend_enter(), create_image() or
resume_target_kernel(), it is necessary to call sysdev_resume(),
because sysdev_suspend() has been called already and succeeded
and we are going to abort the transition.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-18 23:58:59 +02:00
Linus Torvalds c78193e9c7 next_pidmap: fix overflow condition
next_pidmap() just quietly accepted whatever 'last' pid that was passed
in, which is not all that safe when one of the users is /proc.

Admittedly the proc code should do some sanity checking on the range
(and that will be the next commit), but that doesn't mean that the
helper functions should just do that pidmap pointer arithmetic without
checking the range of its arguments.

So clamp 'last' to PID_MAX_LIMIT.  The fact that we then do "last+1"
doesn't really matter, the for-loop does check against the end of the
pidmap array properly (it's only the actual pointer arithmetic overflow
case we need to worry about, and going one bit beyond isn't going to
overflow).

[ Use PID_MAX_LIMIT rather than pid_max as per Eric Biederman ]

Reported-by: Tavis Ormandy <taviso@cmpxchg8b.com>
Analyzed-by: Robert Święcki <robert@swiecki.net>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-18 10:35:30 -07:00
Ingo Molnar 6ddafdaab3 Merge branch 'sched/locking' into sched/core
Merge reason: the rq locking changes are stable,
              propagate them into the .40 queue.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-18 14:53:33 +02:00
Richard Cochran 1791f88143 posix clocks: Replace mutex with reader/writer semaphore
A dynamic posix clock is protected from asynchronous removal by a mutex.
However, using a mutex has the unwanted effect that a long running clock
operation in one process will unnecessarily block other processes.

For example, one process might call read() to get an external time stamp
coming in at one pulse per second. A second process calling clock_gettime
would have to wait for almost a whole second.

This patch fixes the issue by using a reader/writer semaphore instead of
a mutex.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/%3C20110330132421.GA31771%40riccoc20.at.omicron.at%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-18 10:39:38 +02:00
Linus Torvalds d733ed6c34 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: make unplug timer trace event correspond to the schedule() unplug
  block: let io_schedule() flush the plug inline
2011-04-16 10:33:41 -07:00
Linus Torvalds fdfc552abe Merge branches 'core-fixes-for-linus', 'perf-fixes-for-linus', 'sched-fixes-for-linus', 'timer-fixes-for-linus' and 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  futex: Set FLAGS_HAS_TIMEOUT during futex_wait restart setup

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf_event: Fix cgrp event scheduling bug in perf_enable_on_exec()
  perf: Fix a build error with some GCC versions

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Fix erroneous all_pinned logic
  sched: Fix sched-domain avg_load calculation

* 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  RTC: rtc-mrst: follow on to the change of rtc_device_register()
  RTC: add missing "return 0" in new alarm func for rtc-bfin.c
  RTC: Fix s3c compile error due to missing s3c_rtc_setpie
  RTC: Fix early irqs caused by calling rtc_set_alarm too early

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, amd: Disable GartTlbWlkErr when BIOS forgets it
  x86, NUMA: Fix fakenuma boot failure
  x86/mrst: Fix boot crash caused by incorrect pin to irq mapping
  x86/ce4100: Add reg property to bridges
2011-04-16 09:45:08 -07:00
Jens Axboe 49cac01e1f block: make unplug timer trace event correspond to the schedule() unplug
It's a pretty close match to what we had before - the timer triggering
would mean that nobody unplugged the plug in due time, in the new
scheme this matches very closely what the schedule() unplug now is.
It's essentially the difference between an explicit unplug (IO unplug)
or an implicit unplug (timer unplug, we scheduled with pending IO
queued).

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-16 13:51:05 +02:00
Jens Axboe a237c1c5bc block: let io_schedule() flush the plug inline
Linus correctly observes that the most important dispatch cases
are now done from kblockd, this isn't ideal for latency reasons.
The original reason for switching dispatches out-of-line was to
avoid too deep a stack, so by _only_ letting the "accidental"
flush directly in schedule() be guarded by offload to kblockd,
we should be able to get the best of both worlds.

So add a blk_schedule_flush_plug() that offloads to kblockd,
and only use that from the schedule() path.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-16 13:27:55 +02:00
Linus Torvalds 5853b4f06f Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: only force kblockd unplugging from the schedule() path
  block: cleanup the block plug helper functions
  block, blk-sysfs: Use the variable directly instead of a function call
  block: move queue run on unplug to kblockd
  block: kill queue_sync_plugs()
  block: readd plug trace event
  block: add callback function for unplug notification
  block: add comment on why we save and disable interrupts in flush_plug_list()
  block: fixup block IO unplug trace call
  block: remove block_unplug_timer() trace point
  block: splice plug list to local context
2011-04-15 08:01:13 -07:00
Darren Hart 0cd9c6494e futex: Set FLAGS_HAS_TIMEOUT during futex_wait restart setup
The FLAGS_HAS_TIMEOUT flag was not getting set, causing the restart_block to
restart futex_wait() without a timeout after a signal.

Commit b41277dc7a in 2.6.38 introduced the regression by accidentally
removing the the FLAGS_HAS_TIMEOUT assignment from futex_wait() during the setup
of the restart block. Restore the originaly behavior.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=32922

Reported-by: Tim Smith <tsmith201104@yahoo.com>
Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/%3Cdaac0eb3af607f72b9a4d3126b2ba8fb5ed3b883.1302820917.git.dvhart%40linux.intel.com%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-15 16:34:32 +02:00
Peter Zijlstra 317f394160 sched: Move the second half of ttwu() to the remote cpu
Now that we've removed the rq->lock requirement from the first part of
ttwu() and can compute placement without holding any rq->lock, ensure
we execute the second half of ttwu() on the actual cpu we want the
task to run on.

This avoids having to take rq->lock and doing the task enqueue
remotely, saving lots on cacheline transfers.

As measured using: http://oss.oracle.com/~mason/sembench.c

  $ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i; done
  $ echo 4096 32000 64 128 > /proc/sys/kernel/sem
  $ ./sembench -t 2048 -w 1900 -o 0

  unpatched: run time 30 seconds 647278 worker burns per second
  patched:   run time 30 seconds 816715 worker burns per second

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152729.515897185@chello.nl
2011-04-14 08:52:41 +02:00
Peter Zijlstra bd8e7dded8 sched: Remove need_migrate_task()
Oleg noticed that need_migrate_task() doesn't need the ->on_cpu check
now that ttwu() doesn't do remote enqueues for !->on_rq && ->on_cpu,
so remove the helper and replace the single instance with a direct
->on_rq test.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.556674812@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:41 +02:00
Peter Zijlstra c05fbafba1 sched: Restructure ttwu() some more
Factor our helper functions to make the inner workings of try_to_wake_up()
more obvious, this also allows for adding remote queues.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152729.475848012@chello.nl
2011-04-14 08:52:40 +02:00
Peter Zijlstra 23f41eeb42 sched: Rename ttwu_post_activation() to ttwu_do_wakeup()
The ttwu_post_activation() code does the core wakeup, it sets TASK_RUNNING
and performs wakeup-preemption, so give is a more descriptive name.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152729.434609705@chello.nl
2011-04-14 08:52:40 +02:00
Peter Zijlstra b84cb5df1f sched: Remove rq argument from ttwu_stat()
In order to call ttwu_stat() without holding rq->lock we must remove
its rq argument. Since we need to change rq stats, account to the
local rq instead of the task rq, this is safe since we have IRQs
disabled.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152729.394638826@chello.nl
2011-04-14 08:52:40 +02:00
Peter Zijlstra e4a52bcb9a sched: Remove rq->lock from the first half of ttwu()
Currently ttwu() does two rq->lock acquisitions, once on the task's
old rq, holding it over the p->state fiddling and load-balance pass.
Then it drops the old rq->lock to acquire the new rq->lock.

By having serialized ttwu(), p->sched_class, p->cpus_allowed with
p->pi_lock, we can now drop the whole first rq->lock acquisition.

The p->pi_lock serializing concurrent ttwu() calls protects p->state,
which we will set to TASK_WAKING to bridge possible p->pi_lock to
rq->lock gaps and serialize set_task_cpu() calls against
task_rq_lock().

The p->pi_lock serialization of p->sched_class allows us to call
scheduling class methods without holding the rq->lock, and the
serialization of p->cpus_allowed allows us to do the load-balancing
bits without races.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152729.354401150@chello.nl
2011-04-14 08:52:39 +02:00
Peter Zijlstra 8f42ced974 sched: Drop rq->lock from sched_exec()
Since we can now call select_task_rq() and set_task_cpu() with only
p->pi_lock held, and sched_exec() load-balancing has always been
optimistic, drop all rq->lock usage.

Oleg also noted that need_migrate_task() will always be true for
current, so don't bother calling that at all.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.314204889@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:39 +02:00
Peter Zijlstra ab2515c4b9 sched: Drop rq->lock from first part of wake_up_new_task()
Since p->pi_lock now protects all things needed to call
select_task_rq() avoid the double remote rq->lock acquisition and rely
on p->pi_lock.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.273362517@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:38 +02:00
Peter Zijlstra 0122ec5b02 sched: Add p->pi_lock to task_rq_lock()
In order to be able to call set_task_cpu() while either holding
p->pi_lock or task_rq(p)->lock we need to hold both locks in order to
stabilize task_rq().

This makes task_rq_lock() acquire both locks, and have
__task_rq_lock() validate that p->pi_lock is held. This increases the
locking overhead for most scheduler syscalls but allows reduction of
rq->lock contention for some scheduler hot paths (ttwu).

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.232781355@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:38 +02:00
Peter Zijlstra 2acca55ed9 sched: Also serialize ttwu_local() with p->pi_lock
Since we now serialize ttwu() using p->pi_lock, we also need to
serialize ttwu_local() using that, otherwise, once we drop the
rq->lock from ttwu() it can race with ttwu_local().

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152729.192366907@chello.nl
2011-04-14 08:52:37 +02:00
Peter Zijlstra a8e4f2eaec sched: Delay task_contributes_to_load()
In prepratation of having to call task_contributes_to_load() without
holding rq->lock, we need to store the result until we do and can
update the rq accounting accordingly.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152729.151523907@chello.nl
2011-04-14 08:52:37 +02:00
Peter Zijlstra 3fe1698b7f sched: Deal with non-atomic min_vruntime reads on 32bits
In order to avoid reading partial updated min_vruntime values on 32bit
implement a seqcount like solution.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.111378493@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:37 +02:00
Peter Zijlstra 74f8e4b233 sched: Remove rq argument to sched_class::task_waking()
In preparation of calling this without rq->lock held, remove the
dependency on the rq argument.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.071474242@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:36 +02:00
Peter Zijlstra 7608dec2ce sched: Drop the rq argument to sched_class::select_task_rq()
In preparation of calling select_task_rq() without rq->lock held, drop
the dependency on the rq argument.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.031077745@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:36 +02:00
Peter Zijlstra 013fdb8086 sched: Serialize p->cpus_allowed and ttwu() using p->pi_lock
Currently p->pi_lock already serializes p->sched_class, also put
p->cpus_allowed and try_to_wake_up() under it, this prepares the way
to do the first part of ttwu() without holding rq->lock.

By having p->sched_class and p->cpus_allowed serialized by p->pi_lock,
we prepare the way to call select_task_rq() without holding rq->lock.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152728.990364093@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:35 +02:00
Peter Zijlstra fd2f4419b4 sched: Provide p->on_rq
Provide a generic p->on_rq because the p->se.on_rq semantics are
unfavourable for lockless wakeups but needed for sched_fair.

In particular, p->on_rq is only cleared when we actually dequeue the
task in schedule() and not on any random dequeue as done by things
like __migrate_task() and __sched_setscheduler().

This also allows us to remove p->se usage from !sched_fair code.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152728.949545047@chello.nl
2011-04-14 08:52:35 +02:00
Peter Zijlstra d7c01d27ab sched: Clean up ttwu() stats
Collect all ttwu() stat code into a single function and ensure its
always called for an actual wakeup (changing p->state to
TASK_RUNNING).

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152728.908177058@chello.nl
2011-04-14 08:52:34 +02:00
Peter Zijlstra 893633817f sched: Change the ttwu() success details
try_to_wake_up() would only return a success when it would have to
place a task on a rq, change that to every time we change p->state to
TASK_RUNNING, because that's the real measure of wakeups.

This results in that success is always true for the tracepoints.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152728.866866929@chello.nl
2011-04-14 08:52:34 +02:00
Peter Zijlstra c2f7115e2e sched: Move wq_worker_waking to the correct site
wq_worker_waking_up() needs to match wq_worker_sleeping(), since the
latter is only called on deactivate, move the former near activate.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/n/top-t3m7n70n9frmv4pv2n5fwmov@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:33 +02:00
Peter Zijlstra c6eb3dda25 mutex: Use p->on_cpu for the adaptive spin
Since we now have p->on_cpu unconditionally available, use it to
re-implement mutex_spin_on_owner.

Requested-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152728.826338173@chello.nl
2011-04-14 08:52:33 +02:00
Peter Zijlstra 3ca7a440da sched: Always provide p->on_cpu
Always provide p->on_cpu so that we can determine if its on a cpu
without having to lock the rq.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152728.785452014@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:52:32 +02:00
Ingo Molnar a4c98f8bbe Merge branch 'linus' into sched/locking
Merge reason: Pick up this upstream commit:

  6631e635c65d: block: don't flush plugged IO on forced preemtion scheduling

As it modifies the scheduler and we'll queue up dependent patches.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-14 08:51:07 +02:00
Linus Torvalds 6631e635c6 block: don't flush plugged IO on forced preemtion scheduling
We really only want to unplug the pending IO when the process actually
goes to sleep.  So move the test for flushing the plug up to the place
where we actually deactivate the task - where we have properly checked
for preemption and for the process really sleeping.

Acked-by: Jens Axboe <jaxboe@fusionio.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-13 08:08:20 -07:00
Jens Axboe 94b5eb28b4 block: fixup block IO unplug trace call
It was removed with the on-stack plugging, readd it and track the
depth of requests added when flushing the plug.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-12 10:12:19 +02:00
Jens Axboe d9c9783317 block: remove block_unplug_timer() trace point
We no longer have an unplug timer running, so no point in keeping
the trace point.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-12 10:06:33 +02:00
Shriram Rajagopalan d419e4c0f7 fix XEN_SAVE_RESTORE Kconfig dependencies
Make XEN_SAVE_RESTORE select HIBERNATE_CALLBACKS.
Remove XEN_SAVE_RESTORE dependency from PM_SLEEP.

Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-04-11 22:54:48 +02:00
Rafael J. Wysocki 1f112cee07 PM / Hibernate: Introduce CONFIG_HIBERNATE_CALLBACKS
Xen save/restore is going to use hibernate device callbacks for
quiescing devices and putting them back to normal operations and it
would need to select CONFIG_HIBERNATION for this purpose.  However,
that also would cause the hibernate interfaces for user space to be
enabled, which might confuse user space, because the Xen kernels
don't support hibernation.  Moreover, it would be wasteful, as it
would make the Xen kernels include a substantial amount of code that
they would never use.

To address this issue introduce new power management Kconfig option
CONFIG_HIBERNATE_CALLBACKS, such that it will only select the code
that is necessary for the hibernate device callbacks to work and make
CONFIG_HIBERNATION select it.  Then, Xen save/restore will be able to
select CONFIG_HIBERNATE_CALLBACKS without dragging the entire
hibernate code along with it.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
2011-04-11 22:54:42 +02:00
Peter Zijlstra 60495e7760 sched: Dynamic sched_domain::level
Remove the SD_LV_ enum and use dynamic level assignments.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.969433965@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 14:09:32 +02:00
Peter Zijlstra 54ab4ff431 sched: Move sched domain storage into the topology list
In order to remove the last dependency on the statid domain levels,
move the sd_data storage into the topology structure.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.924926412@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 14:09:31 +02:00
Peter Zijlstra d069b916f7 sched: Reverse the topology list
In order to get rid of static sched_domain::level assignments, reverse
the topology iteration.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.876506131@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 14:09:29 +02:00
Peter Zijlstra 2c402dc3bb sched: Unify the sched_domain build functions
Since all the __build_$DOM_sched_domain() functions do pretty much the
same thing, unify them.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.826347257@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 14:09:27 +02:00
Peter Zijlstra eb7a74e6cd sched: Stuff the sched_domain creation in a data-structure
In order to make the topology contruction fully dynamic, remove the
still hard-coded list of possible domains and stick them in a
data-structure.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.770335383@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 14:09:26 +02:00
Peter Zijlstra d3081f52f2 sched: Create proper cpu_$DOM_mask() functions
In order to unify the sched domain creation more, create proper
cpu_$DOM_mask() functions for those domains that didn't already have
one.

Use the sched_domains_tmpmask for the weird NUMA domain span.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.717702108@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 14:09:24 +02:00
Peter Zijlstra 4cb988395d sched: Avoid allocations in sched_domain_debug()
Since we're all serialized by sched_domains_mutex we can use
sched_domains_tmpmask and avoid having to do allocations. This means
we can use sched_domains_debug() for cpu_attach_domain() again.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.664347467@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 14:05:00 +02:00
Peter Zijlstra f96225fd51 sched: Create persistent sched_domains_tmpmask
Since sched domain creation is fully serialized by the
sched_domains_mutex we can create a single persistent tmpmask to use
during domain creation.

This removes the need for s_data::send_covered.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.607287405@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:23 +02:00
Peter Zijlstra 7dd04b7307 sched: Remove some dead code
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.553814623@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:22 +02:00
Peter Zijlstra bf28b25326 sched: Remove nodemask allocation
There's only one nodemask user left so remove it with a direct
computation and save some memory and reduce some code-flow
complexity.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.505608966@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:22 +02:00
Peter Zijlstra 3bd65a80af sched: Simplify NODE/ALLNODES domain creation
Don't treat ALLNODES/NODE different for difference's sake. Simply
always create the ALLNODES domain and let the sd_degenerate() checks
kill it when its redundant. This simplifies the code flow.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.455464579@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:21 +02:00
Peter Zijlstra a6c75f2f8d sched: Avoid using sd->level
Don't use sd->level for identifying properties of the domain.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.350174079@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:20 +02:00
Peter Zijlstra 822ff793c3 sched: Simplify the free path some
If we check the root_domain reference count we can see if its been
used or not, use this observation to simplify some of the return
paths.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.298339503@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:20 +02:00
Peter Zijlstra dce840a087 sched: Dynamically allocate sched_domain/sched_group data-structures
Instead of relying on static allocations for the sched_domain and
sched_group trees, dynamically allocate and RCU free them.

Allocating this dynamically also allows for some build_sched_groups()
simplification since we can now (like with other simplifications) rely
on the sched_domain tree instead of hard-coded knowledge.

One tricky to note is that detach_destroy_domains() needs to hold
rcu_read_lock() over the entire tear-down, per-cpu is not sufficient
since that can lead to partial sched_group existance (could possibly
be solved by doing the tear-down backwards but this is much more
robust).

A concequence of the above is that we can no longer print the
sched_domain debug stuff from cpu_attach_domain() since that might now
run with preemption disabled (due to classic RCU etc.) and
sched_domain_debug() does some GFP_KERNEL allocations.

Another thing to note is that we now fully rely on normal RCU and not
RCU-sched, this is because with the new and exiting RCU flavours we
grew over the years BH doesn't necessarily hold off RCU-sched grace
periods (-rt is known to break this). This would in fact already cause
us grief since we do sched_domain/sched_group iterations from softirq
context.

This patch is somewhat larger than I would like it to be, but I didn't
find any means of shrinking/splitting this.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.245307941@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:19 +02:00
Peter Zijlstra a9c9a9b6bf sched: Simplify sched_groups_power initialization
Again, instead of relying on knowing the possible domains and their
order, simply rely on the sched_domain tree and whatever domains are
present in there to initialize the sched_group cpu_power.

Note: we need to iterate the CPU mask backwards because of the
cpumask_first() condition for iterating up the tree. By iterating the
mask backwards we ensure all groups of a domain are set-up before
starting on the parent groups that rely on its children to be
completely done.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.187335414@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:19 +02:00
Peter Zijlstra 21d42ccfd6 sched: Simplify finding the lowest sched_domain
Instead of relying on knowing the build order and various CONFIG_
flags simply remember the bottom most sched_domain when we created the
domain hierarchy.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.134511046@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:19 +02:00
Peter Zijlstra 1cf5190254 sched: Simplify sched_group creation
Instead of calling build_sched_groups() for each possible sched_domain
we might have created, note that we can simply iterate the
sched_domain tree and call it for each sched_domain present.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.077862519@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:18 +02:00
Peter Zijlstra 3739494e08 sched: Clean up some ALLNODES code
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.025636011@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:18 +02:00
Peter Zijlstra cd4ea6ae39 sched: Change NODE sched_domain group creation
The NODE sched_domain is 'special' in that it allocates sched_groups
per CPU, instead of sharing the sched_groups between all CPUs.

While this might have some benefits on large NUMA and avoid remote
memory accesses when iterating the sched_groups, this does break
current code that assumes sched_groups are shared between all
sched_domains (since the dynamic cpu_power patches).

So refactor the NODE groups to behave like all other groups.

(The ALLNODES domain again shared its groups across the CPUs for some
reason).

If someone does measure a performance decrease due to this change we
need to revisit this and come up with another way to have both dynamic
cpu_power and NUMA work nice together.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122941.978111700@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:17 +02:00
Peter Zijlstra a06dadbec5 sched: Simplify build_sched_groups()
Notice that the mask being computed is the same as the domain span we
just computed. By using the domain_span we can avoid some mask
allocations and computations.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122941.925028189@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:17 +02:00
Peter Zijlstra d274cb30f4 sched: Simplify ->cpu_power initialization
The code in update_group_power() does what init_sched_groups_power()
does and more, so remove the special init_ code and call the generic
code instead.

Also move the sd->span_weight initialization because
update_group_power() needs it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122941.875856012@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:16 +02:00
Peter Zijlstra c4a8849af9 sched: Remove obsolete arch_ prefixes
Non weak static functions clearly are not arch specific, so remove the
arch_ prefix.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122941.820460566@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 12:58:16 +02:00
Shaohua Li f4ad9bd208 sched: Eliminate dead code from wakeup_gran()
calc_delta_fair() checks NICE_0_LOAD already, delete duplicate check.

Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1302238389.3981.92.camel@sli10-conroe
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 11:08:55 +02:00
Ken Chen b30aef17f7 sched: Fix erroneous all_pinned logic
The scheduler load balancer has specific code to deal with cases of
unbalanced system due to lots of unmovable tasks (for example because of
hard CPU affinity). In those situation, it excludes the busiest CPU that
has pinned tasks for load balance consideration such that it can perform
second 2nd load balance pass on the rest of the system.

This all works as designed if there is only one cgroup in the system.

However, when we have multiple cgroups, this logic has false positives and
triggers multiple load balance passes despite there are actually no pinned
tasks at all.

The reason it has false positives is that the all pinned logic is deep in
the lowest function of can_migrate_task() and is too low level:

load_balance_fair() iterates each task group and calls balance_tasks() to
migrate target load. Along the way, balance_tasks() will also set a
all_pinned variable. Given that task-groups are iterated, this all_pinned
variable is essentially the status of last group in the scanning process.
Task group can have number of reasons that no load being migrated, none
due to cpu affinity. However, this status bit is being propagated back up
to the higher level load_balance(), which incorrectly think that no tasks
were moved.  It kick off the all pinned logic and start multiple passes
attempt to move load onto puller CPU.

To fix this, move the all_pinned aggregation up at the iterator level.
This ensures that the status is aggregated over all task-groups, not just
last one in the list.

Signed-off-by: Ken Chen <kenchen@google.com>
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/BANLkTi=ernzNawaR5tJZEsV_QVnfxqXmsQ@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 11:08:54 +02:00
Ken Chen b0432d8f16 sched: Fix sched-domain avg_load calculation
In function find_busiest_group(), the sched-domain avg_load isn't
calculated at all if there is a group imbalance within the domain. This
will cause erroneous imbalance calculation.

The reason is that calculate_imbalance() sees sds->avg_load = 0 and it
will dump entire sds->max_load into imbalance variable, which is used
later on to migrate entire load from busiest CPU to the puller CPU.

This has two really bad effect:

1. stampede of task migration, and they won't be able to break out
   of the bad state because of positive feedback loop: large load
   delta -> heavier load migration -> larger imbalance and the cycle
   goes on.

2. severe imbalance in CPU queue depth.  This causes really long
   scheduling latency blip which affects badly on application that
   has tight latency requirement.

The fix is to have kernel calculate domain avg_load in both cases. This
will ensure that imbalance calculation is always sensible and the target
is usually half way between busiest and puller CPU.

Signed-off-by: Ken Chen <kenchen@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/20110408002322.3A0D812217F@elm.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 11:08:54 +02:00
Stephane Eranian e566b76ed3 perf_event: Fix cgrp event scheduling bug in perf_enable_on_exec()
There is a bug in perf_event_enable_on_exec() when cgroup events are
active on a CPU: the cgroup events may be scheduled twice causing event
state corruptions which eventually may lead to kernel panics.

The reason is that the function needs to first schedule out the cgroup
events, just like for the per-thread events. The cgroup event are
scheduled back in automatically from the perf_event_context_sched_in()
function.

The patch also adds a WARN_ON_ONCE() is perf_cgroup_switch() to catch any
bogus state.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110406005454.GA1062@quad
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-11 11:07:55 +02:00
Justin P. Mattock 6875669906 arch:Kconfig.locks Remove unused config option.
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-10 17:01:05 +02:00
Justin P. Mattock 6eab04a876 treewide: remove extra semicolons
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-10 17:01:05 +02:00
Randy Dunlap f9fa0bc1fa signal.c: fix erroneous syscall kernel-doc
Fix erroneous syscall kernel-doc comments in kernel/signal.c.

Reported-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-08 11:05:24 -07:00
Linus Torvalds 8b9686ff4d Merge branches 'x86-fixes-for-linus', 'sched-fixes-for-linus', 'timers-fixes-for-linus', 'irq-fixes-for-linus' and 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86-32, fpu: Fix FPU exception handling on non-SSE systems
  x86, hibernate: Initialize mmu_cr4_features during boot
  x86-32, NUMA: Fix ACPI NUMA init broken by recent x86-64 change
  x86: visws: Fixup irq overhaul fallout

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Clean up rebalance_domains() load-balance interval calculation

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86/mrst/vrtc: Fix boot crash in mrst_rtc_init()
  rtc, x86/mrst/vrtc: Fix boot crash in rtc_read_alarm()

* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq: Fix cpumask leak in __setup_irq()

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf probe: Fix listing incorrect line number with inline function
  perf probe: Fix to find recursively inlined function
  perf probe: Fix multiple --vars options behavior
  perf probe: Fix to remove redundant close
  perf probe: Fix to ensure function declared file
2011-04-07 12:12:58 -07:00
Oleg Nesterov e46bc9b6fd Merge branch 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into ptrace 2011-04-07 20:44:11 +02:00
Linus Torvalds 42933bac11 Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6
* 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6:
  Fix common misspellings
2011-04-07 11:14:49 -07:00
Peter Zijlstra 49c022e657 sched: Clean up rebalance_domains() load-balance interval calculation
Instead of the possible multiple-evaluation of num_online_cpus()
in rebalance_domains() that Linus reported, avoid it altogether
in the normal case since it's implemented with a Hamming weight
function over a cpu bitmask which can be darn expensive for those
with big iron.

This also makes it cleaner, smaller and documents the code.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1301991265.2225.12.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-05 10:29:36 +02:00
Randy Dunlap 41c57892a2 kernel/signal.c: add kernel-doc notation to syscalls
Add kernel-doc to syscalls in signal.c.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-04 17:51:46 -07:00
Randy Dunlap 5aba085ede kernel/signal.c: fix typos and coding style
General coding style and comment fixes; no code changes:

 - Use multi-line-comment coding style.
 - Put some function signatures completely on one line.
 - Hyphenate some words.
 - Spell Posix as POSIX.
 - Correct typos & spellos in some comments.
 - Drop trailing whitespace.
 - End sentences with periods.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-04 17:51:46 -07:00
Jason Baron d430d3d7e6 jump label: Introduce static_branch() interface
Introduce:

static __always_inline bool static_branch(struct jump_label_key *key);

instead of the old JUMP_LABEL(key, label) macro.

In this way, jump labels become really easy to use:

Define:

        struct jump_label_key jump_key;

Can be used as:

        if (static_branch(&jump_key))
                do unlikely code

enable/disale via:

        jump_label_inc(&jump_key);
        jump_label_dec(&jump_key);

that's it!

For the jump labels disabled case, the static_branch() becomes an
atomic_read(), and jump_label_inc()/dec() are simply atomic_inc(),
atomic_dec() operations. We show testing results for this change below.

Thanks to H. Peter Anvin for suggesting the 'static_branch()' construct.

Since we now require a 'struct jump_label_key *key', we can store a pointer into
the jump table addresses. In this way, we can enable/disable jump labels, in
basically constant time. This change allows us to completely remove the previous
hashtable scheme. Thanks to Peter Zijlstra for this re-write.

Testing:

I ran a series of 'tbench 20' runs 5 times (with reboots) for 3
configurations, where tracepoints were disabled.

jump label configured in
avg: 815.6

jump label *not* configured in (using atomic reads)
avg: 800.1

jump label *not* configured in (regular reads)
avg: 803.4

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110316212947.GA8792@redhat.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Suggested-by: H. Peter Anvin <hpa@linux.intel.com>
Tested-by: David Daney <ddaney@caviumnetworks.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-04 12:48:08 -04:00
Jiri Olsa ee5e51f51b tracing: Avoid soft lockup in trace_pipe
running following commands:

  # enable the binary option
  echo 1 > ./options/bin
  # disable context info option
  echo 0 > ./options/context-info
  # tracing only events
  echo 1 > ./events/enable
  cat trace_pipe

plus forcing system to generate many tracing events,
is causing lockup (in NON preemptive kernels) inside
tracing_read_pipe function.

The issue is also easily reproduced by running ltp stress test.
(ftrace_stress_test.sh)

The reasons are:
 - bin/hex/raw output functions for events are set to
   trace_nop_print function, which prints nothing and
   returns TRACE_TYPE_HANDLED value
 - LOST EVENT trace do not handle trace_seq overflow

These reasons force the while loop in tracing_read_pipe
function never to break.

The attached patch fixies handling of lost event trace, and
changes trace_nop_print to print minimal info, which is needed
for the correct tracing_read_pipe processing.

v2 changes:
 - omit the cond_resched changes by trace_nop_print changes
 - WARN changed to WARN_ONCE and added info to be able
   to find out the culprit

v3 changes:
 - make more accurate patch comment

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <20110325110518.GC1922@jolsa.brq.redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-04 12:18:24 -04:00
Steven Rostedt 1813dc3776 tracing: Print trace_bprintk() formats for modules too
The file debugfs/tracing/printk_formats maps the addresses
to the formats that are used by trace_bprintk() so that userspace
tools can read the buffer and be able to decode trace_bprintk events
to get the format saved when reading the ring buffer directly.

This is because trace_bprintk() does not store the format into the
buffer, but just the address of the format, which is hidden in
the kernel memory.

But currently it only exports trace_bprintk()s from the kernel core
and not for modules. The modules need their formats exported
as well.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-04 12:18:24 -04:00
Steven Rostedt 0588fa30db tracing: Convert trace_printk() formats for module to const char *
The trace_printk() formats for modules do not show up in the
debugfs/tracing/printk_formats file. Only the formats that are
for trace_printk()s that are in the kernel core.

To facilitate the change to add trace_printk() formats from modules
into that file as well, we need to convert the structure that
holds the formats from char fmt[], into const char *fmt,
and allocate them separately.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-04 12:18:24 -04:00
Linus Torvalds 148086bb64 Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Fix rebalance interval calculation
  sched, doc: Beef up load balancing description
  sched: Leave sched_setscheduler() earlier if possible, do not disturb SCHED_FIFO tasks
2011-04-04 08:36:58 -07:00
Linus Torvalds 4da7e90e65 Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf: Fix task_struct reference leak
  perf: Fix task context scheduling
  perf: mmap 512 kiB by default
  perf: Rebase max unprivileged mlock threshold on top of page size
  perf tools: Fix NO_NEWT=1 python build error
  perf symbols: Properly align symbol_conf.priv_size
  perf tools: Emit clearer message for sys_perf_event_open ENOENT return
  perf tools: Fixup exit path when not able to open events
  perf symbols: Fix vsyscall symbol lookup
  oprofile, x86: Allow setting EDGE/INV/CMASK for counter events
2011-04-04 08:36:40 -07:00
Richard Cochran 4352d9d44b ntp: fix non privileged system time shifting
The ADJ_SETOFFSET bit added in commit 094aa188 ("ntp: Add ADJ_SETOFFSET
mode bit") also introduced a way for any user to change the system time.
Sneaky or buggy calls to adjtimex() could set

    ADJ_OFFSET_SS_READ | ADJ_SETOFFSET

which would result in a successful call to timekeeping_inject_offset().
This patch fixes the issue by adding the capability check.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-04 08:31:23 -07:00
Eric Paris a3232d2fa2 capabilities: delete all CAP_INIT macros
The CAP_INIT macros of INH, BSET, and EFF made sense at one point in time,
but now days they aren't helping.  Just open code the logic in the
init_cred.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2011-04-04 10:31:16 +10:00
Eric Paris 5163b583a0 capabilities: delete unused cap_set_full
unused code.  Clean it up.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
2011-04-04 10:31:12 +10:00
Eric Paris ffa8e59df0 capabilities: do not drop CAP_SETPCAP from the initial task
In olden' days of yore CAP_SETPCAP had special meaning for the init task.
We actually have code to make sure that CAP_SETPCAP wasn't in pE of things
using the init_cred.  But CAP_SETPCAP isn't so special any more and we
don't have a reason to special case dropping it for init or kthreads....

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
2011-04-04 10:31:09 +10:00
Eric Paris 17f60a7da1 capabilites: allow the application of capability limits to usermode helpers
There is no way to limit the capabilities of usermodehelpers. This problem
reared its head recently when someone complained that any user with
cap_net_admin was able to load arbitrary kernel modules, even though the user
didn't have cap_sys_module.  The reason is because the actual load is done by
a usermode helper and those always have the full cap set.  This patch addes new
sysctls which allow us to bound the permissions of usermode helpers.

/proc/sys/kernel/usermodehelper/bset
/proc/sys/kernel/usermodehelper/inheritable

You must have CAP_SYS_MODULE  and CAP_SETPCAP to change these (changes are
&= ONLY).  When the kernel launches a usermodehelper it will do so with these
as the bset and pI.

-v2:	make globals static
	create spinlock to protect globals

-v3:	require both CAP_SETPCAP and CAP_SYS_MODULE
-v4:	fix the typo s/CAP_SET_PCAP/CAP_SETPCAP/ because I didn't commit
Signed-off-by: Eric Paris <eparis@redhat.com>
No-objection-from: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
2011-04-04 10:31:04 +10:00
Oleg Nesterov 321fb56197 ptrace: ptrace_check_attach() should not do s/STOPPED/TRACED/
After "ptrace: Clean transitions between TASK_STOPPED and TRACED"
d79fdd6d96, ptrace_check_attach()
should never see a TASK_STOPPED tracee and s/STOPPED/TRACED/ is
no longer legal. Add the warning.

Note: ptrace_check_attach() can be greatly simplified, in particular
it doesn't need tasklist. But I'd prefer another patch for that.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2011-04-04 02:11:05 +02:00
Oleg Nesterov ee77f07592 signal: Turn SIGNAL_STOP_DEQUEUED into GROUP_STOP_DEQUEUED
This patch moves SIGNAL_STOP_DEQUEUED from signal_struct->flags to
task_struct->group_stop, and thus makes it per-thread.

Like SIGNAL_STOP_DEQUEUED, GROUP_STOP_DEQUEUED can be false-positive
after return from get_signal_to_deliver(), this is fine. The only
purpose of this bit is: we can drop ->siglock after __dequeue_signal()
returns the sig_kernel_stop() signal and before we call
do_signal_stop(), in this case we must not miss SIGCONT if it comes in
between.

But, unlike SIGNAL_STOP_DEQUEUED, GROUP_STOP_DEQUEUED can not be
false-positive in do_signal_stop() if multiple threads dequeue the
sig_kernel_stop() signal at the same time.

Consider two threads T1 and T2, SIGTTIN has a hanlder.

	- T1 dequeues SIGTSTP and sets SIGNAL_STOP_DEQUEUED, then
	  it drops ->siglock

	- SIGCONT comes and clears SIGNAL_STOP_DEQUEUED, SIGTSTP
	  should be cancelled.

	- T2 dequeues SIGTTIN and sets SIGNAL_STOP_DEQUEUED again.
	  Since we have a handler we should not stop, T2 returns
	  to usermode to run the handler.

	- T1 continues, calls do_signal_stop() and wrongly starts
	  the group stop because SIGNAL_STOP_DEQUEUED was restored
	  in between.

With or without this change:

	- we need to do something with ptrace_signal() which can
	  return SIGSTOP, but this needs another discussion

	- SIGSTOP can be lost if it races with the mt exec, will
	  be fixed later.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2011-04-04 02:11:05 +02:00
Oleg Nesterov 780006eac2 signal: do_signal_stop: Remove the unneeded task_clear_group_stop_pending()
PF_EXITING or TASK_STOPPED has already called task_participate_group_stop()
and cleared its ->group_stop. No need to do task_clear_group_stop_pending()
when we start the new group stop.

Add a small comment to explain the !task_is_stopped() check. Note that this
check is not exactly right and it can lead to unnecessary stop later if the
thread is TASK_PTRACED. What we need is task_participated_in_group_stop(),
this will be solved later.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2011-04-04 02:11:04 +02:00
Oleg Nesterov 1deac632fc signal: prepare_signal(SIGCONT) shouldn't play with TIF_SIGPENDING
prepare_signal(SIGCONT) should never set TIF_SIGPENDING or wake up
the TASK_INTERRUPTIBLE threads. We are going to call complete_signal()
which should pick the right thread correctly. All we need is to wake
up the TASK_STOPPED threads.

If the task was stopped, it can't return to usermode without taking
->siglock. Otherwise we don't care, and the spurious TIF_SIGPENDING
can't be useful.

The comment says:

	* If there is a handler for SIGCONT, we must make
	* sure that no thread returns to user mode before
	* we post the signal

It is not clear what this means. Probably, "when there's only a single
thread" and this continues to be true. Otherwise, even if this SIGCONT
is not private, with or without this change only one thread can dequeue
SIGCONT, other threads can happily return to user mode before before
that thread handles this signal.

Note also that wake_up_state(t, __TASK_STOPPED) can't race with the task
which changes its state, TASK_STOPPED state is protected by ->siglock as
well.

In short: when it comes to signal delivery, SIGCONT is the normal signal
and does not need any special support.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2011-04-04 02:11:04 +02:00
Xiaotian Feng 4f5058c3b7 genirq: Fix cpumask leak in __setup_irq()
The allocated cpumask should be freed in __setup_irq().

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
LKML-Reference: <1301744375-6812-1-git-send-email-dfeng@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-02 21:26:20 +02:00
Anton Blanchard c0bb9e45f3 kdump: Allow shrinking of kdump region to be overridden
On ppc64 the crashkernel region almost always overlaps an area of firmware.
This works fine except when using the sysfs interface to reduce the kdump
region. If we free the firmware area we are guaranteed to crash.

Rename free_reserved_phys_range to crash_free_reserved_phys_range and make
it a weak function so we can override it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-01 16:14:30 +11:00
Lucas De Marchi 25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Peter Zijlstra fd1edb3aa2 perf: Fix task_struct reference leak
sys_perf_event_open() had an imbalance in the number of task refs it
took causing memory leakage

Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: stable@kernel.org # .37+
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-31 13:02:56 +02:00
Frederic Weisbecker 20443384fe perf: Rebase max unprivileged mlock threshold on top of page size
Ensure we allow 512 kiB + 1 page for user control without
assuming a 4096 bytes page size.

Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: <stable@kernel.org>
LKML-Reference: <1301535209-9679-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-31 13:02:54 +02:00
Sisir Koppaka 3436ae1298 sched: Fix rebalance interval calculation
The interval for checking scheduling domains if they are due to be
balanced currently depends on boot state NR_CPUS, which may not
accurately reflect the number of online CPUs at the time of check.

Thus replace NR_CPUS with num_online_cpus().

 (ed: Should only affect those who set NR_CPUS really high, such as 4096
      or so :-)

Signed-off-by: Sisir Koppaka <sisir.koppaka@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <AANLkTikqHWid2Q93F5U5Qw5snJH8C5PXoa7J6=6hYO94@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-31 13:00:37 +02:00
Dario Faggioli a51e919818 sched: Leave sched_setscheduler() earlier if possible, do not disturb SCHED_FIFO tasks
sched_setscheduler() (in sched.c) is called in order of changing the
scheduling policy and/or the real-time priority of a task. Thus,
if we find out that neither of those are actually being modified, it
is possible to return earlier and save the overhead of a full
deactivate+activate cycle of the task in question.

Beside that, if we have more than one SCHED_FIFO task with the same
priority on the same rq (which means they share the same priority queue)
having one of them changing its position in the priority queue because of
a sched_setscheduler (as it happens by means of the deactivate+activate)
that does not actually change the priority violates POSIX which states,
for SCHED_FIFO:

  "If a thread whose policy or priority has been modified by
   pthread_setschedprio() is a running thread or is runnable, the effect on
   its position in the thread list depends on the direction of the
   modification, as follows: a. <...> b. If the priority is unchanged, the
   thread does not change position in the thread list. c. <...>"

     http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_08.html

 (ed: And the POSIX specification here does, briefly and somewhat unexpectedly,
      match what common sense tells us as well. )

Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1300971618.3960.82.camel@Palantir>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-31 13:00:34 +02:00
Thomas Gleixner 78c8982564 genirq: Remove the now obsolete config options and select statements
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-30 14:13:23 +02:00
Thomas Gleixner 353c8ed44f genirq: Fix misnamed label in handle_edge_eoi_irq
Reported-by: michael@ellerman.id.au
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linuxppc-dev@lists.ozlabs.org
2011-03-29 22:24:05 +02:00
Thomas Gleixner 851d7cf647 genirq: Remove move_*irq leftovers
All users converted to new interface.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-29 14:50:32 +02:00
Thomas Gleixner 0c6f8a8b91 genirq: Remove compat code
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-29 14:48:19 +02:00
Thomas Gleixner a6e120ed42 alpha: Use generic show_interrupts()
The only subtle difference is that alpha uses ACTUAL_NR_IRQS and
prints the IRQF_DISABLED flag.

Change the generic implementation to deal with ACTUAL_NR_IRQS if
defined.

The IRQF_DISABLED printing is pointless, as we nowadays run all
interrupts with irqs disabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-29 14:47:58 +02:00
Thomas Gleixner cd22c0e44b genirq: Fix harmless typo
The late night fixup missed to convert the data type from irq_desc to
irq_data, which results in a harmless but annoying warning.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-29 11:36:05 +02:00
Linus Torvalds e5217fb8ae Merge branches 'irq-cleanup-for-linus' and 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'irq-cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  vlynq: Convert irq functions

* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq; Fix cleanup fallout
  genirq: Fix typo and remove unused variable
  genirq: Fix new kernel-doc warnings
  genirq: Add setter for AFFINITY_SET in irq_data state
  genirq: Provide setter inline for IRQD_IRQ_INPROGRESS
  genirq: Remove handle_IRQ_event
  arm: Ns9xxx: Remove private irq flow handler
  powerpc: cell: Use the core flow handler
  genirq: Provide edge_eoi flow handler
  genirq: Move INPROGRESS, MASKED and DISABLED state flags to irq_data
  genirq: Split irq_set_affinity() so it can be called with lock held.
  genirq: Add chip flag for restricting cpu_on/offline calls
  genirq: Add chip hooks for taking CPUs on/off line.
  genirq: Add irq disabled flag to irq_data state
  genirq: Reserve the irq when calling irq_set_chip()
2011-03-28 17:39:54 -07:00
Thomas Gleixner 0ef5ca1e1f genirq; Fix cleanup fallout
I missed the CONFIG_GENERIC_PENDING_IRQ dependency in the affinity
related functions and the IRQ_LEVEL propagation into irq_data
state. Did not pop up on my main test platforms. :(

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: David Daney <ddaney@caviumnetworks.com>
2011-03-29 01:41:22 +02:00
Roland Dreier 243b422af9 Relax si_code check in rt_sigqueueinfo and rt_tgsigqueueinfo
Commit da48524eb2 ("Prevent rt_sigqueueinfo and rt_tgsigqueueinfo
from spoofing the signal code") made the check on si_code too strict.
There are several legitimate places where glibc wants to queue a
negative si_code different from SI_QUEUE:

 - This was first noticed with glibc's aio implementation, which wants
   to queue a signal with si_code SI_ASYNCIO; the current kernel
   causes glibc's tst-aio4 test to fail because rt_sigqueueinfo()
   fails with EPERM.

 - Further examination of the glibc source shows that getaddrinfo_a()
   wants to use SI_ASYNCNL (which the kernel does not even define).
   The timer_create() fallback code wants to queue signals with SI_TIMER.

As suggested by Oleg Nesterov <oleg@redhat.com>, loosen the check to
forbid only the problematic SI_TKILL case.

Reported-by: Klaus Dittrich <kladit@arcor.de>
Acked-by: Julien Tinnes <jln@google.com>
Cc: <stable@kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-28 15:45:44 -07:00
Thomas Gleixner a6aeddd1c4 genirq: Fix typo and remove unused variable
Sigh, I'm overworked.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-28 20:28:56 +02:00
Randy Dunlap 30398bf6c6 genirq: Fix new kernel-doc warnings
Fix new irq-related kernel-doc warnings in 2.6.38:

Warning(kernel/irq/manage.c:149): No description found for parameter 'mask'
Warning(kernel/irq/manage.c:149): Excess function parameter 'cpumask' description in 'irq_set_affinity'
Warning(include/linux/irq.h:161): No description found for parameter 'state_use_accessors'
Warning(include/linux/irq.h:161): Excess struct/union/enum/typedef member 'state_use_accessor' description in 'irq_data'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <20110318093356.b939558d.randy.dunlap@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-28 20:13:57 +02:00
Thomas Gleixner 33b054b867 genirq: Remove handle_IRQ_event
Last user gone.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-28 16:55:11 +02:00
Thomas Gleixner 0521c8fbb3 genirq: Provide edge_eoi flow handler
This is a replacment for the cell flow handler which is in the way of
cleanups. Must be selected to avoid general bloat.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-28 16:55:11 +02:00
Thomas Gleixner 32f4125ebf genirq: Move INPROGRESS, MASKED and DISABLED state flags to irq_data
We really need these flags for some of the interrupt chips. Move it
from internal state to irq_data and provide proper accessors.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Daney <ddaney@caviumnetworks.com>
2011-03-28 16:55:10 +02:00
David Daney c2d0c555c2 genirq: Split irq_set_affinity() so it can be called with lock held.
The .irq_cpu_online() and .irq_cpu_offline() functions may need to
adjust affinity, but they are called with the descriptor lock held.
Create __irq_set_affinity_locked() which is called with the lock held.
Make irq_set_affinity() just a wrapper that acquires the lock.

[ tglx: Changed the argument to irq_data, added a !desc check and
        moved the !irq_set_affinity check where it belongs ]

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: ralf@linux-mips.org
LKML-Reference: <1301081931-11240-4-git-send-email-ddaney@caviumnetworks.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-27 17:45:59 +02:00
Thomas Gleixner b3d422329f genirq: Add chip flag for restricting cpu_on/offline calls
Add a flag which indicates that the on/offline callback should only be
called on enabled interrupts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-27 17:45:58 +02:00
David Daney 0fdb4b259e genirq: Add chip hooks for taking CPUs on/off line.
[ tglx: Removed the enabled argument as this is now available in
irq_data ]

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: ralf@linux-mips.org
LKML-Reference: <1301081931-11240-3-git-send-email-ddaney@caviumnetworks.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-27 17:45:58 +02:00
Thomas Gleixner 801a0e9ae3 genirq: Add irq disabled flag to irq_data state
Some irq_chip implementation require to know the disabled state of the
interrupt in certain callbacks. Add a state flag and accessor to
irq_data.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-27 17:45:58 +02:00
David Daney d72274e589 genirq: Reserve the irq when calling irq_set_chip()
The helper macros and functions like for_each_active_irq() don't work
unless the irq is in the allocated_irqs set.

In the case of !CONFIG_SPARSE_IRQ, instead of forcing all users of the
irq infrastructure to explicitly call irq_reserve_irq(), do it for
them.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: ralf@linux-mips.org
LKML-Reference: <1301081931-11240-2-git-send-email-ddaney@caviumnetworks.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-27 17:45:58 +02:00
Linus Torvalds 16c29dafcc Merge branch 'syscore' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6
* 'syscore' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  Introduce ARCH_NO_SYSDEV_OPS config option (v2)
  cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
  KVM: Use syscore_ops instead of sysdev class and sysdev
  PCI / Intel IOMMU: Use syscore_ops instead of sysdev class and sysdev
  timekeeping: Use syscore_ops instead of sysdev class and sysdev
  x86: Use syscore_ops instead of sysdev classes and sysdevs
2011-03-25 21:07:59 -07:00
Linus Torvalds 95e14ed7fc Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kdb: add usage string of 'per_cpu' command
  kgdb,x86_64: fix compile warning found with sparse
  kdb: code cleanup to use macro instead of value
  kgdboc,kgdbts: strlen() doesn't count the terminator
2011-03-25 21:04:56 -07:00
Linus Torvalds 0dd61be7ec Merge branch 'irq-cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'irq-cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (23 commits)
  genirq: Expand generic show_interrupts()
  gpio: Fold irq_set_chip/irq_set_handler to irq_set_chip_and_handler
  gpio: Cleanup genirq namespace
  arm: ep93xx: Add basic interrupt info
  arm/gpio: Remove three copies of broken and racy debug code
  xtensa: Use generic show_interrupts()
  xtensa: Convert genirq namespace
  xtensa: Use generic IRQ Kconfig and set GENERIC_HARDIRQS_NO_DEPRECATED
  xtensa: Convert s6000 gpio irq_chip to new functions
  xtensa: Convert main irq_chip to new functions
  um: Use generic show_interrupts()
  um: Convert genirq namespace
  m32r: Use generic show_interrupts()
  m32r: Convert genirq namespace
  h8300: Use generic show_interrupts()
  h8300: Convert genirq namespace
  avr32: Cleanup eic_set_irq_type()
  avr32: Use generic show_interrupts()
  avr: Cleanup genirq namespace
  avr32: Use generic IRQ config, enable GENERIC_HARDIRQS_NO_DEPRECATED
  ...

Fix up trivial conflict in drivers/gpio/timbgpio.c
2011-03-25 20:24:05 -07:00
Linus Torvalds 8dd90265ac Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched, doc: Update sched-design-CFS.txt
  sched: Remove unused 'rq' variable and cpu_rq() call from alloc_fair_sched_group()
  sched.h: Fix a typo ("its")
  sched: Fix yield_to kernel-doc
2011-03-25 17:59:38 -07:00
Linus Torvalds 2a20b02c05 Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf, x86: Complain louder about BIOSen corrupting CPU/PMU state and continue
  perf, x86: P4 PMU - Read proper MSR register to catch unflagged overflows
  perf symbols: Look at .dynsym again if .symtab not found
  perf build-id: Add quirk to deal with perf.data file format breakage
  perf session: Pass evsel in event_ops->sample()
  perf: Better fit max unprivileged mlock pages for tools needs
  perf_events: Fix stale ->cgrp pointer in update_cgrp_time_from_cpuctx()
  perf top: Fix uninitialized 'counter' variable
  tracing: Fix set_ftrace_filter probe function display
  perf, x86: Fix Intel fixed counters base initialization
2011-03-25 17:53:09 -07:00