12676 Commits

Author SHA1 Message Date
Steven Rostedt
77271ce4b2 tracing: Add irq, preempt-count and need resched info to default trace output
People keep asking how to get the preempt count, irq, and need resched info
and we keep telling them to enable the latency format. Some developers think
that traces without this info is completely useless, and for a lot of tasks
it is useless.

The first option was to enable the latency trace as the default format, but
the header for the latency format is pretty useless for most tracers and
it also does the timestamp in straight microseconds from the time the trace
started. This is sometimes more difficult to read as the default trace is
seconds from the start of boot up.

Latency format:

 # tracer: nop
 #
 # nop latency trace v1.1.5 on 3.2.0-rc1-test+
 # --------------------------------------------------------------------
 # latency: 0 us, #159771/64234230, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4)
 #    -----------------
 #    | task: -0 (uid:0 nice:0 policy:0 rt_prio:0)
 #    -----------------
 #
 #                  _------=> CPU#
 #                 / _-----=> irqs-off
 #                | / _----=> need-resched
 #                || / _---=> hardirq/softirq
 #                ||| / _--=> preempt-depth
 #                |||| /     delay
 #  cmd     pid   ||||| time  |   caller
 #     \   /      |||||  \    |   /
 migratio-6       0...2 41778231us+: rcu_note_context_switch <-__schedule
 migratio-6       0...2 41778233us : trace_rcu_utilization <-rcu_note_context_switch
 migratio-6       0...2 41778235us+: rcu_sched_qs <-rcu_note_context_switch
 migratio-6       0d..2 41778236us+: rcu_preempt_qs <-rcu_note_context_switch
 migratio-6       0...2 41778238us : trace_rcu_utilization <-rcu_note_context_switch
 migratio-6       0...2 41778239us+: debug_lockdep_rcu_enabled <-__schedule

default format:

 # tracer: nop
 #
 #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
 #              | |       |          |         |
      migration/0-6     [000]    50.025810: rcu_note_context_switch <-__schedule
      migration/0-6     [000]    50.025812: trace_rcu_utilization <-rcu_note_context_switch
      migration/0-6     [000]    50.025813: rcu_sched_qs <-rcu_note_context_switch
      migration/0-6     [000]    50.025815: rcu_preempt_qs <-rcu_note_context_switch
      migration/0-6     [000]    50.025817: trace_rcu_utilization <-rcu_note_context_switch
      migration/0-6     [000]    50.025818: debug_lockdep_rcu_enabled <-__schedule
      migration/0-6     [000]    50.025820: debug_lockdep_rcu_enabled <-__schedule

The latency format header has latency information that is pretty meaningless
for most tracers. Although some of the header is useful, and we can add that
later to the default format as well.

What is really useful with the latency format is the irqs-off, need-resched
hard/softirq context and the preempt count.

This commit adds the option irq-info which is on by default that adds this
information:

 # tracer: nop
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
           <idle>-0     [000] d..2    49.309305: cpuidle_get_driver <-cpuidle_idle_call
           <idle>-0     [000] d..2    49.309307: mwait_idle <-cpu_idle
           <idle>-0     [000] d..2    49.309309: need_resched <-mwait_idle
           <idle>-0     [000] d..2    49.309310: test_ti_thread_flag <-need_resched
           <idle>-0     [000] d..2    49.309312: trace_power_start.constprop.13 <-mwait_idle
           <idle>-0     [000] d..2    49.309313: trace_cpu_idle <-mwait_idle
           <idle>-0     [000] d..2    49.309315: need_resched <-mwait_idle

If a user wants the old format, they can disable the 'irq-info' option:

 # tracer: nop
 #
 #           TASK-PID   CPU#      TIMESTAMP  FUNCTION
 #              | |       |          |         |
           <idle>-0     [000]     49.309305: cpuidle_get_driver <-cpuidle_idle_call
           <idle>-0     [000]     49.309307: mwait_idle <-cpu_idle
           <idle>-0     [000]     49.309309: need_resched <-mwait_idle
           <idle>-0     [000]     49.309310: test_ti_thread_flag <-need_resched
           <idle>-0     [000]     49.309312: trace_power_start.constprop.13 <-mwait_idle
           <idle>-0     [000]     49.309313: trace_cpu_idle <-mwait_idle
           <idle>-0     [000]     49.309315: need_resched <-mwait_idle

Requested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-17 09:58:48 -05:00
Linus Torvalds
aa1b052a34 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Fix irqfixup, irqpoll regression
2011-11-17 11:46:26 -02:00
Wu Fengguang
468e6a20af writeback: remove vm_dirties and task->dirties
They are not used any more.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-11-17 20:49:06 +08:00
Peter Zijlstra
391e43da79 sched: Move all scheduler bits into kernel/sched/
There's too many sched*.[ch] files in kernel/, give them their own
directory.

(No code changed, other than Makefile glue added.)

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-17 12:20:22 +01:00
Peter Zijlstra
029632fbb7 sched: Make separate sched*.c translation units
Since once needs to do something at conferences and fixing compile
warnings doesn't actually require much if any attention I decided
to break up the sched.c #include "*.c" fest.

This further modularizes the scheduler code.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-x0fcd3mnp8f9c99grcpewmhi@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-17 12:20:19 +01:00
Richard Weinberger
60686317da sched: Fix comment for requeue_rt_entity
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1321117677-3282-1-git-send-email-richard@nod.at
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-16 08:48:27 +01:00
Andrew Vagin
a3e5d1091c sched: Don't call task_group() too many times in set_task_rq()
It improves perfomance, especially if autogroup is enabled.

The size of set_task_rq() was 0x180 and now it is 0xa0.

Signed-off-by: Andrew Vagin <avagin@openvz.org>
Acked-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1321020240-3874331-1-git-send-email-avagin@openvz.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-16 08:48:24 +01:00
Glauber Costa
f4d6f6c264 sched, trivial: Initialize root cgroup's sibling list
Even though there are no siblings, the list should be
initialized to not contain bogus values.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Paul Menage <paul@paulmenage.org>
Acked-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1320182360-20043-2-git-send-email-glommer@parallels.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-16 08:48:22 +01:00
Paul Turner
56f570e512 sched: Use jump labels to reduce overhead when bandwidth control is inactive
Now that the linkage of jump-labels has been fixed they show a measurable
improvement in overhead for the enabled-but-unused case.

Workload is:

 'taskset -c 0 perf stat --repeat 50 -e instructions,cycles,branches
  bash -c "for ((i=0;i<5;i++)); do $(dirname $0)/pipe-test 20000; done"'

There's a speedup for all situations:

                 instructions            cycles                  branches
 -------------------------------------------------------------------------
 Intel Westmere
 base            806611770               745895590               146765378
 +jumplabel      803090165 (-0.44%)      713381840 (-4.36%)      144561130

 AMD Barcelona
 base            824657415               740055589               148855354
 +jumplabel      821056910 (-0.44%)      737558389 (-0.34%)      146635229

Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111108042736.560831357@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-16 08:48:18 +01:00
Paul Turner
fccfdc6f0d sched: Fix buglet in return_cfs_rq_runtime()
In return_cfs_rq_runtime() we want to return bandwidth when there are no
remaining tasks, not "return" when this is the case.

Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111108042736.623812423@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-16 08:43:45 +01:00
Peter Zijlstra
4dcfe1025b sched: Avoid SMT siblings in select_idle_sibling() if possible
Avoid select_idle_sibling() from picking a sibling thread if there's
an idle core that shares cache.

This fixes SMT balancing in the increasingly common case where there's
a shared cache core available to balance to.

Tested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1321350377.1421.55.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-16 08:43:43 +01:00
Ingo Molnar
c23205c848 Merge branch 'core' of git://amd64.org/linux/rric into perf/core 2011-11-15 11:05:18 +01:00
Yong Zhang
87cdee7116 lockdep: Always try to set ->class_cache in register_lock_class() lockdep_init_map()
Commit ["62016250 lockdep: Add improved subclass caching"] tries to
improve performance (expecially to reduce the cost of rq->lock)
when using lockdep, but it fails due to lockdep_init_map() in
which ->class_cache is cleared. The typical caller is
lock_set_subclass(), after that class will not be cached anymore.

This patch tries to achive the goal of commit 62016250 by always
setting ->class_cache in register_lock_class().

=== Score comparison of benchmarks ===

for i in `seq 1 10`; do ./perf bench -f simple sched messaging; done

before:  min: 0.604, max: 0.660, avg: 0.622
after:   min: 0.414, max: 0.473, avg: 0.427

for i in `seq 1 10`; do ./perf bench -f simple sched messaging -g 40; done

before:  min: 2.347, max: 2.421, avg: 2.391
after:   min: 1.652, max: 1.699, avg: 1.671

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111109080714.GC8124@zhy
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 13:54:11 +01:00
Peter Zijlstra
1a9a8aefa8 printk, lockdep: Switch to tracked irq ops
Switch to local_irq_ ops so that the irq state is properly tracked
(raw_local_irq_* isn't tracked by lockdep, causing confusion).

Possible now that commit dd4e5d3ac4a ("lockdep: Fix
trace_[soft,hard]irqs_[on,off]() recursion") cured the reason we
needed the raw_ ops.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 13:35:20 +01:00
Peter Zijlstra
47ff5c95db printk, lockdep: Remove superfluous preempt_disable()
The raw_lock_irq_{save,restore}() already implies a
non-preemptibility.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 13:35:18 +01:00
Peter Zijlstra
94d24fc472 printk, lockdep: Disable lock debugging on zap_locks()
zap_locks() is used by printk() in a last ditch effort to get data
out, clearly we cannot trust lock state after this so make it disable
lock debugging.

Also don't treat printk recursion through lockdep as a normal
recursion bug but try hard to get the lockdep splat out.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-kqxwmo4xz37e1s8w0xopvr0q@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 13:35:16 +01:00
Andrew Vagin
5d81e5cfb3 events: Don't divide events if it has field period
This patch solves the following problem:

Now some samples may be lost due to throttling. The number of samples is
restricted by sysctl_perf_event_sample_rate/HZ.  A trace event is
divided on some samples according to event's period.  I don't sure, that
we should generate more than one sample on each trace event. I think the
better way to use SAMPLE_PERIOD.

E.g.: I want to trace when a process sleeps. I created a process, which
sleeps for 1ms and for 4ms.  perf got 100 events in both cases.

swapper     0 [000]  1141.371830: sched_stat_sleep: comm=foo pid=1801 delay=1386750 [ns]
swapper     0 [000]  1141.369444: sched_stat_sleep: comm=foo pid=1801 delay=4499585 [ns]

In the first case a kernel want to send 4499585 events and
in the second case it wants to send 1386750 events.
perf-reports shows that process sleeps in both places equal time. It's
bug.

With this patch kernel generates one event on each "sleep" and the time
slice is saved in the field "period". Perf knows how handle it.

Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1320670457-2633428-3-git-send-email-avagin@openvz.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 13:31:28 +01:00
Borislav Petkov
9251f904f9 perf: Carve out callchain functionality
Split the callchain code from the perf events core into
a new kernel/events/callchain.c file.

This simplifies a bit the big core.c

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
[keep ctx recursion handling inline and use internal headers]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1318778104-17152-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 13:31:26 +01:00
Gleb Natapov
1d5f003f5a perf: Do not set task_ctx pointer in cpuctx if there are no events in the context
Do not set task_ctx pointer during sched_in if there are no
events associated with the context.  Otherwise if during task
execution total number of events in the system will become zero
perf_event_context_sched_out() will not be called and cpuctx->task_ctx
will be left with a stale value.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111023171033.GI17571@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 13:01:21 +01:00
Carsten Emde
f1c6f1a7ee sched: Set the command name of the idle tasks in SMP kernels
In UP systems, the idle task is initialized using the init_task
structure from which the command name is taken (currently "swapper").

In SMP systems, one idle task per CPU is forked by the worker thread
from which the task structure is copied. The command name is, therefore,
"kworker/0:0" or "kworker/0:1", if not updated. Since such update was
lacking, all idle tasks in SMP systems were incorrectly named. This
longtime bug was not discovered immediately, because there is no /proc/0
entry - the bug only becomes apparent when tracing is enabled.

This patch sets the command name of the idle tasks in SMP systems to the
name that is used in the INIT_TASK structure suffixed by a slash and the
number of the CPU.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111026211708.768925506@osadl.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 12:50:43 +01:00
Peter Zijlstra
4a6184ce7a sched, rt: Provide means of disabling cross-cpu bandwidth sharing
Normally the RT bandwidth scheme will share bandwidth across the
entire root_domain. However sometimes its convenient to disable this
sharing for debug purposes. Provide a simple feature switch to this
end.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 12:50:40 +01:00
J. Bruce Fields
c6dc7f055d sched: Document wait_for_completion_*() return values
The return-value convention for these functions varies depending on
whether they're interruptible or can timeout.  It can be a little
confusing--document it.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111006192246.GB28026@fieldses.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 12:50:37 +01:00
Hui Kang
461819ac8e sched_fair: Fix a typo in the comment describing update_sd_lb_stats
Signed-off-by: Hui Kang <hkang.sunysb@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1318388459-4427-1-git-send-email-hkang.sunysb@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 12:50:34 +01:00
Peter Zijlstra
cf5f0acf39 sched: Add a comment to effective_load() since it's a pain
Every time I have to stare at this function I need to completely
reverse engineer its workings, about time I write a comment
explaining the thing.

Collected bits and pieces from previous changelogs, mostly:

  4be9daaa1b33701f011f4117f22dc1e45a3e6e34
  83378269a5fad98f562ebc0f09c349575e6cbfe1

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1318518057.27731.2.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-11-14 12:50:32 +01:00
Jiri Kosina
2290c0d06d Merge branch 'master' into for-next
Sync with Linus tree to have 157550ff ("mtd: add GPMI-NAND driver
in the config and Makefile") as I have patch depending on that one.
2011-11-13 20:55:53 +01:00
Ingo Molnar
efc96737bd Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core 2011-11-11 08:19:37 +01:00
Ingo Molnar
367177e501 Merge branch 'formingo/3.2/tip/timers/core' of git://git.linaro.org/people/jstultz/linux into timers/core
Conflicts:
	kernel/time/timekeeping.c
2011-11-11 08:10:42 +01:00
John Stultz
d65670a78c clocksource: Avoid selecting mult values that might overflow when adjusted
For some frequencies, the clocks_calc_mult_shift() function will
unfortunately select mult values very close to 0xffffffff.  This
has the potential to overflow when NTP adjusts the clock, adding
to the mult value.

This patch adds a clocksource.maxadj value, which provides
an approximation of an 11% adjustment(NTP limits adjustments to
500ppm and the tick adjustment is limited to 10%), which could
be made to the clocksource.mult value. This is then used to both
check that the current mult value won't overflow/underflow, as
well as warning us if the timekeeping_adjust() code pushes over
that 11% boundary.

v2: Fix max_adjustment calculation, and improve WARN_ONCE
messages.

v3: Don't warn before maxadj has actually been set

CC: Yong Zhang <yong.zhang0@gmail.com>
CC: David Daney <ddaney.cavm@gmail.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Chen Jie <chenj@lemote.com>
CC: zhangfx <zhangfx@lemote.com>
CC: stable@kernel.org
Reported-by: Chen Jie <chenj@lemote.com>
Reported-by: zhangfx <zhangfx@lemote.com>
Tested-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-11-10 11:27:08 -08:00
Robert Richter
de346b6949 Merge branch 'perf/core' into oprofile/master
Merge reason: Resolve conflicts with Don's NMI rework:

    commit 9c48f1c629ecfa114850c03f875c6691003214de
    Author: Don Zickus <dzickus@redhat.com>
    Date:   Fri Sep 30 15:06:21 2011 -0400
    x86, nmi: Wire up NMI handlers to new routines

Conflicts:
	arch/x86/oprofile/nmi_timer_int.c

Signed-off-by: Robert Richter <robert.richter@amd.com>
2011-11-08 15:52:15 +01:00
Dominik Brodowski
a6f05b97d1 PM / QoS: Set cpu_dma_pm_qos->name
Since commit 4a31a334, the name of this misc device is not initialized,
which leads to a funny device named /dev/(null) being created and
/proc/misc containing an entry with just a number but no name. The latter
leads to complaints by cryptsetup, which caused me to investigate this
matter.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-11-07 23:02:24 +01:00
Jiri Olsa
7e9a49ef54 tracing/latency: Fix header output for latency tracers
In case the the graph tracer (CONFIG_FUNCTION_GRAPH_TRACER) or even the
function tracer (CONFIG_FUNCTION_TRACER) are not set, the latency tracers
do not display proper latency header.

The involved/fixed latency tracers are:
        wakeup_rt
        wakeup
        preemptirqsoff
        preemptoff
        irqsoff

The patch adds proper handling of tracer configuration options for latency
tracers, and displaying correct header info accordingly.

* The current output (for wakeup tracer) with both graph and function
  tracers disabled is:

  # tracer: wakeup
  #
    <idle>-0       0d.h5    1us+:      0:120:R   + [000]     7:  0:R watchdog/0
    <idle>-0       0d.h5    3us+: ttwu_do_activate.clone.1 <-try_to_wake_up
    ...

* The fixed output is:

  # tracer: wakeup
  #
  # wakeup latency trace v1.1.5 on 3.1.0-tip+
  # --------------------------------------------------------------------
  # latency: 55 us, #4/4, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
  #    -----------------
  #    | task: migration/0-6 (uid:0 nice:0 policy:1 rt_prio:99)
  #    -----------------
  #
  #                  _------=> CPU#
  #                 / _-----=> irqs-off
  #                | / _----=> need-resched
  #                || / _---=> hardirq/softirq
  #                ||| / _--=> preempt-depth
  #                |||| /     delay
  #  cmd     pid   ||||| time  |   caller
  #     \   /      |||||  \    |   /
       cat-1129    0d..4    1us :   1129:120:R   + [000]     6:  0:R migration/0
       cat-1129    0d..4    2us+: ttwu_do_activate.clone.1 <-try_to_wake_up

* The current output (for wakeup tracer) with only function
  tracer enabled is:

  # tracer: wakeup
  #
       cat-1140    0d..4    1us+:   1140:120:R   + [000]     6:  0:R migration/0
       cat-1140    0d..4    2us : ttwu_do_activate.clone.1 <-try_to_wake_up

* The fixed output is:
  # tracer: wakeup
  #
  # wakeup latency trace v1.1.5 on 3.1.0-tip+
  # --------------------------------------------------------------------
  # latency: 207 us, #109/109, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
  #    -----------------
  #    | task: watchdog/1-12 (uid:0 nice:0 policy:1 rt_prio:99)
  #    -----------------
  #
  #                  _------=> CPU#
  #                 / _-----=> irqs-off
  #                | / _----=> need-resched
  #                || / _---=> hardirq/softirq
  #                ||| / _--=> preempt-depth
  #                |||| /     delay
  #  cmd     pid   ||||| time  |   caller
  #     \   /      |||||  \    |   /
    <idle>-0       1d.h5    1us+:      0:120:R   + [001]    12:  0:R watchdog/1
    <idle>-0       1d.h5    3us : ttwu_do_activate.clone.1 <-try_to_wake_up

Link: http://lkml.kernel.org/r/20111107150849.GE1807@m.brq.redhat.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-07 13:48:35 -05:00
Steven Rostedt
d4d34b981a ftrace: Fix hash record accounting bug
If the set_ftrace_filter is cleared by writing just whitespace to
it, then the filter hash refcounts will be decremented but not
updated. This causes two bugs:

1) No functions will be enabled for tracing when they all should be

2) If the users clears the set_ftrace_filter twice, it will crash ftrace:

------------[ cut here ]------------
WARNING: at /home/rostedt/work/git/linux-trace.git/kernel/trace/ftrace.c:1384 __ftrace_hash_rec_update.part.27+0x157/0x1a7()
Modules linked in:
Pid: 2330, comm: bash Not tainted 3.1.0-test+ #32
Call Trace:
 [<ffffffff81051828>] warn_slowpath_common+0x83/0x9b
 [<ffffffff8105185a>] warn_slowpath_null+0x1a/0x1c
 [<ffffffff810ba362>] __ftrace_hash_rec_update.part.27+0x157/0x1a7
 [<ffffffff810ba6e8>] ? ftrace_regex_release+0xa7/0x10f
 [<ffffffff8111bdfe>] ? kfree+0xe5/0x115
 [<ffffffff810ba51e>] ftrace_hash_move+0x2e/0x151
 [<ffffffff810ba6fb>] ftrace_regex_release+0xba/0x10f
 [<ffffffff8112e49a>] fput+0xfd/0x1c2
 [<ffffffff8112b54c>] filp_close+0x6d/0x78
 [<ffffffff8113a92d>] sys_dup3+0x197/0x1c1
 [<ffffffff8113a9a6>] sys_dup2+0x4f/0x54
 [<ffffffff8150cac2>] system_call_fastpath+0x16/0x1b
---[ end trace 77a3a7ee73794a02 ]---

Link: http://lkml.kernel.org/r/20111101141420.GA4918@debian

Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-07 13:48:05 -05:00
Gleb Natapov
c8452afb74 jump_label: jump_label_inc may return before the code is patched
If cpu A calls jump_label_inc() just after atomic_add_return() is
called by cpu B, atomic_inc_not_zero() will return value greater then
zero and jump_label_inc() will return to a caller before jump_label_update()
finishes its job on cpu B.

Link: http://lkml.kernel.org/r/20111018175551.GH17571@redhat.com

Cc: stable@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-07 11:02:34 -05:00
Steven Rostedt
8ee3c92b7f ftrace: Remove force undef config value left for testing
A forced undef of a config value was used for testing and was
accidently left in during the final commit. This causes x86 to
run slower than needed while running function tracing as well
as causes the function graph selftest to fail when DYNMAIC_FTRACE
is not set. This is because the code in MCOUNT expects the ftrace
code to be processed with the config value set that happened to
be forced not set.

The forced config option was left in by:
    commit 6331c28c962561aee59e5a493b7556a4bb585957
    ftrace: Fix dynamic selftest failure on some archs

Link: http://lkml.kernel.org/r/20111102150255.GA6973@debian

Cc: stable@vger.kernel.org
Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-07 11:02:33 -05:00
Steven Rostedt
e5e78d08f3 lockdep: Show subclass in pretty print of lockdep output
The pretty print of the lockdep debug splat uses just the lock name
to show how the locking scenario happens. But when it comes to
nesting locks, the output becomes confusing which takes away the point
of the pretty printing of the lock scenario.

Without displaying the subclass info, we get the following output:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(slock-AF_INET);
                                lock(slock-AF_INET);
                                lock(slock-AF_INET);
   lock(slock-AF_INET);

  *** DEADLOCK ***

The above looks more of a A->A locking bug than a A->B B->A.
By adding the subclass to the output, we can see what really happened:

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(slock-AF_INET);
                                lock(slock-AF_INET/1);
                                lock(slock-AF_INET);
   lock(slock-AF_INET/1);

  *** DEADLOCK ***

This bug was discovered while tracking down a real bug caught by lockdep.

Link: http://lkml.kernel.org/r/20111025202049.GB25043@hostway.ca

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Simon Kirby <sim@hostway.ca>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-07 11:01:46 -05:00
Linus Torvalds
b32fc0a062 Merge branch 'upstream/jump-label-noearly' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
* 'upstream/jump-label-noearly' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
  jump-label: initialize jump-label subsystem much earlier
  x86/jump_label: add arch_jump_label_transform_static()
  s390/jump-label: add arch_jump_label_transform_static()
  jump_label: add arch_jump_label_transform_static() to optimise non-live code updates
  sparc/jump_label: drop arch_jump_label_text_poke_early()
  x86/jump_label: drop arch_jump_label_text_poke_early()
  jump_label: if a key has already been initialized, don't nop it out
  stop_machine: make stop_machine safe and efficient to call early
  jump_label: use proper atomic_t initializer

Conflicts:
 - arch/x86/kernel/jump_label.c
	Added __init_or_module to arch_jump_label_text_poke_early vs
	removal of that function entirely
 - kernel/stop_machine.c
	same patch ("stop_machine: make stop_machine safe and efficient
	to call early") merged twice, with whitespace fix in one version
2011-11-06 20:20:46 -08:00
Linus Torvalds
32aaeffbd4 Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h
2011-11-06 19:44:47 -08:00
Linus Torvalds
208bca0860 Merge branch 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
* 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: Add a 'reason' to wb_writeback_work
  writeback: send work item to queue_io, move_expired_inodes
  writeback: trace event balance_dirty_pages
  writeback: trace event bdi_dirty_ratelimit
  writeback: fix ppc compile warnings on do_div(long long, unsigned long)
  writeback: per-bdi background threshold
  writeback: dirty position control - bdi reserve area
  writeback: control dirty pause time
  writeback: limit max dirty pause time
  writeback: IO-less balance_dirty_pages()
  writeback: per task dirty rate limit
  writeback: stabilize bdi->dirty_ratelimit
  writeback: dirty rate control
  writeback: add bg_threshold parameter to __bdi_update_bandwidth()
  writeback: dirty position control
  writeback: account per-bdi accumulated dirtied pages
2011-11-06 19:02:23 -08:00
Linus Torvalds
d4a2e61f0b Merge git://github.com/rustyrussell/linux
* git://github.com/rustyrussell/linux:
  module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree
  module: Enable dynamic debugging regardless of taint
2011-11-06 17:28:32 -08:00
Linus Torvalds
1197ab2942 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (106 commits)
  powerpc/p3060qds: Add support for P3060QDS board
  powerpc/83xx: Add shutdown request support to MCU handling on MPC8349 MITX
  powerpc/85xx: Make kexec to interate over online cpus
  powerpc/fsl_booke: Fix comment in head_fsl_booke.S
  powerpc/85xx: issue 15 EOI after core reset for FSL CoreNet devices
  powerpc/8xxx: Fix interrupt handling in MPC8xxx GPIO driver
  powerpc/85xx: Add 'fsl,pq3-gpio' compatiable for GPIO driver
  powerpc/86xx: Correct Gianfar support for GE boards
  powerpc/cpm: Clear muram before it is in use.
  drivers/virt: add ioctl for 32-bit compat on 64-bit to fsl-hv-manager
  powerpc/fsl_msi: add support for "msi-address-64" property
  powerpc/85xx: Setup secondary cores PIR with hard SMP id
  powerpc/fsl-booke: Fix settlbcam for 64-bit
  powerpc/85xx: Adding DCSR node to dtsi device trees
  powerpc/85xx: clean up FPGA device tree nodes for Freecsale QorIQ boards
  powerpc/85xx: fix PHYS_64BIT selection for P1022DS
  powerpc/fsl-booke: Fix setup_initial_memory_limit to not blindly map
  powerpc: respect mem= setting for early memory limit setup
  powerpc: Update corenet64_smp_defconfig
  powerpc: Update mpc85xx/corenet 32-bit defconfigs
  ...

Fix up trivial conflicts in:
 - arch/powerpc/configs/40x/hcu4_defconfig
	removed stale file, edited elsewhere
 - arch/powerpc/include/asm/udbg.h, arch/powerpc/kernel/udbg.c:
	added opal and gelic drivers vs added ePAPR driver
 - drivers/tty/serial/8250.c
	moved UPIO_TSI to powerpc vs removed UPIO_DWAPB support
2011-11-06 17:12:03 -08:00
Ben Hutchings
2449b8ba07 module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree
Use of the GPL or a compatible licence doesn't necessarily make the code
any good.  We already consider staging modules to be suspect, and this
should also be true for out-of-tree modules which may receive very
little review.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Reviewed-by: Dave Jones <davej@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (patched oops-tracing.txt)
2011-11-07 07:54:42 +10:30
Ben Hutchings
1cd0d6c302 module: Enable dynamic debugging regardless of taint
Dynamic debugging is currently disabled for tainted modules, except
for TAINT_CRAP.  This prevents use of dynamic debugging for
out-of-tree modules once the next patch is applied.

This condition was apparently intended to avoid a crash if a force-
loaded module has an incompatible definition of dynamic debug
structures.  However, a administrator that forces us to load a module
is claiming that it *is* compatible even though it fails our version
checks.  If they are mistaken, there are any number of ways the module
could crash the system.

As a side-effect, proprietary and other tainted modules can now use
dynamic_debug.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-07 07:54:40 +10:30
Steven Rostedt
49aa29513e tracing: Add boiler plate for subsystem filter
The system filter can be used to set multiple event filters that
exist within the system. But currently it displays the last filter
written that does not necessarily correspond to the filters within
the system. The system filter itself is not used to filter any events.
The system filter is just a means to set filters of the events within
it.

Because this causes an ambiguous state when the system filter reads
a filter string but the events within the system have different strings
it is best to just show a boiler plate:

 ### global filter ###
 # Use this to set filters for multiple events.
 # Only events with the given fields will be affected.
 # If no events are modified, an error message will be displayed here.

If an error occurs while writing to the system filter, the system
filter will replace the boiler plate with the error message as it
currently does.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-04 21:25:36 -04:00
Tejun Heo
d6cc76856d PM / Freezer: Revert 27920651fe "PM / Freezer: Make fake_signal_wake_up() wake TASK_KILLABLE tasks too"
Commit 27920651fe "PM / Freezer: Make fake_signal_wake_up() wake
TASK_KILLABLE tasks too" updated fake_signal_wake_up() used by freezer
to wake up KILLABLE tasks.  Sending unsolicited wakeups to tasks in
killable sleep is dangerous as there are code paths which depend on
tasks not waking up spuriously from KILLABLE sleep.

For example. sys_read() or page can sleep in TASK_KILLABLE assuming
that wait/down/whatever _killable can only fail if we can not return
to the usermode.  TASK_TRACED is another obvious example.

The previous patch updated wait_event_freezekillable() such that it
doesn't depend on the spurious wakeup.  This patch reverts the
offending commit.

Note that the spurious KILLABLE wakeup had other implicit effects in
KILLABLE sleeps in nfs and cifs and those will need further updates to
regain freezekillable behavior.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-11-04 22:28:15 +01:00
Guennadi Liakhovetski
6513fd6972 PM / QoS: Remove redundant check
Remove an "if" check, that repeats an equivalent one 6 lines above.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-11-04 22:28:14 +01:00
Srivatsa S. Bhat
79cfbdfa87 PM / Sleep: Fix race between CPU hotplug and freezer
The CPU hotplug notifications sent out by the _cpu_up() and _cpu_down()
functions depend on the value of the 'tasks_frozen' argument passed to them
(which indicates whether tasks have been frozen or not).
(Examples for such CPU hotplug notifications: CPU_ONLINE, CPU_ONLINE_FROZEN,
CPU_DEAD, CPU_DEAD_FROZEN).

Thus, it is essential that while the callbacks for those notifications are
running, the state of the system with respect to the tasks being frozen or
not remains unchanged, *throughout that duration*. Hence there is a need for
synchronizing the CPU hotplug code with the freezer subsystem.

Since the freezer is involved only in the Suspend/Hibernate call paths, this
patch hooks the CPU hotplug code to the suspend/hibernate notifiers
PM_[SUSPEND|HIBERNATE]_PREPARE and PM_POST_[SUSPEND|HIBERNATE] to prevent
the race between CPU hotplug and freezer, thus ensuring that CPU hotplug
notifications will always be run with the state of the system really being
what the notifications indicate, _throughout_ their execution time.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-11-04 22:28:09 +01:00
Robert Richter
dcfce4a095 oprofile, x86: Reimplement nmi timer mode using perf event
The legacy x86 nmi watchdog code was removed with the implementation
of the perf based nmi watchdog. This broke Oprofile's nmi timer
mode. To run nmi timer mode we relied on a continuous ticking nmi
source which the nmi watchdog provided. The nmi tick was no longer
available and current watchdog can not be used anymore since it runs
with very long periods in the range of seconds. This patch
reimplements the nmi timer mode using a perf counter nmi source.

V2:
* removing pr_info()
* fix undefined reference to `__udivdi3' for 32 bit build
* fix section mismatch of .cpuinit.data:nmi_timer_cpu_nb
* removed nmi timer setup in arch/x86
* implemented function stubs for op_nmi_init/exit()
* made code more readable in oprofile_init()

V3:
* fix architectural initialization in oprofile_init()
* fix CONFIG_OPROFILE_NMI_TIMER dependencies

Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Robert Richter <robert.richter@amd.com>
2011-11-04 16:27:18 +01:00
Linus Torvalds
4536e4d1d2 Revert "perf: Add PM notifiers to fix CPU hotplug races"
This reverts commit 144060fee07e9c22e179d00819c83c86fbcbf82c.

It causes a resume regression for Andi on his Acer Aspire 1830T post
3.1.  The screen just stays black after wakeup.

Also, it really looks like the wrong way to suspend and resume perf
events: I think they should be done as part of the CPU suspend and
resume, rather than as a notifier that does smp_call_function().

Reported-by: Andi Kleen <andi@firstfloor.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-03 07:44:04 -07:00
Edward Donovan
c75d720fca genirq: Fix irqfixup, irqpoll regression
commit d05c65fff0 ("genirq: spurious: Run only one poller at a time")
introduced a regression, leaving the boot options 'irqfixup' and
'irqpoll' non-functional. The patch placed tests in each function, to
exit if the function is already running. The test in 'misrouted_irq'
exited when it should have proceeded, effectively disabling
'misrouted_irq' and 'poll_spurious_irqs'.

The check for an already running poller needs to be "!= 1" not "== 1"
as "1" is the value when the first poller starts running.

Signed-off-by: Edward Donovan <edward.donovan@numble.net>
Cc: maciej.rutecki@gmail.com
Link: http://lkml.kernel.org/r/1320175784-6745-1-git-send-email-edward.donovan@numble.net
Cc: stable@vger.kernel.org # >= 2.6.39
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-11-03 13:12:39 +01:00
Andrew Bresticker
c1e2ee2dc4 memcg: replace ss->id_lock with a rwlock
While back-porting Johannes Weiner's patch "mm: memcg-aware global
reclaim" for an internal effort, we noticed a significant performance
regression during page-reclaim heavy workloads due to high contention of
the ss->id_lock.  This lock protects idr map, and serializes calls to
idr_get_next() in css_get_next() (which is used during the memcg hierarchy
walk).

Since idr_get_next() is just doing a look up, we need only serialize it
with respect to idr_remove()/idr_get_new().  By making the ss->id_lock a
rwlock, contention is greatly reduced and performance improves.

Tested: cat a 256m file from a ramdisk in a 128m container 50 times on
each core (one file + container per core) in parallel on a NUMA machine.
Result is the time for the test to complete in 1 of the containers.
Both kernels included Johannes' memcg-aware global reclaim patches.

Before rwlock patch: 1710.778s
After rwlock patch: 152.227s

Signed-off-by: Andrew Bresticker <abrestic@google.com>
Cc: Paul Menage <menage@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:07:03 -07:00