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Commit Graph

9887 Commits

Author SHA1 Message Date
Frederic Weisbecker
669336e4cf perf: Use tracepoint_synchronize_unregister() to flush any pending tracepoint call
We use synchronize_sched() to ensure a tracepoint won't be called
while/after we release the perf buffers it references.

But the tracepoint API has its own API for that:
tracepoint_synchronize_unregister(). Use it instead as it's
self-explanatory and eases maintainance.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
2010-08-02 01:30:56 +02:00
Ingo Molnar
3a01736e70 Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core 2010-07-23 09:10:29 +02:00
Dan Carpenter
24a461d537 trace: strlen() return doesn't account for the NULL
We need to add one to the strlen() return because of the NULL
character.  The type->name here generally comes from the kernel and I
don't think any of them come close to being MAX_TRACER_SIZE (100)
characters long so this is basically a cleanup.

Signed-off-by: Dan Carpenter <error27@gmail.com>
LKML-Reference: <20100710100644.GV19184@bicker>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-22 14:56:41 -04:00
Ingo Molnar
23c2875725 Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core 2010-07-21 21:44:18 +02:00
Ingo Molnar
9dcdbf7a33 Merge branch 'linus' into perf/core
Merge reason: Pick up the latest perf fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-07-21 21:43:06 +02:00
KOSAKI Motohiro
ef710e100c tracing: Shrink max latency ringbuffer if unnecessary
Documentation/trace/ftrace.txt says

  buffer_size_kb:

        This sets or displays the number of kilobytes each CPU
        buffer can hold. The tracer buffers are the same size
        for each CPU. The displayed number is the size of the
        CPU buffer and not total size of all buffers. The
        trace buffers are allocated in pages (blocks of memory
        that the kernel uses for allocation, usually 4 KB in size).
        If the last page allocated has room for more bytes
        than requested, the rest of the page will be used,
        making the actual allocation bigger than requested.
        ( Note, the size may not be a multiple of the page size
          due to buffer management overhead. )

        This can only be updated when the current_tracer
        is set to "nop".

But it's incorrect. currently total memory consumption is
'buffer_size_kb x CPUs x 2'.

Why two times difference is there? because ftrace implicitly allocate
the buffer for max latency too.

That makes sad result when admin want to use large buffer. (If admin
want full logging and makes detail analysis). example, If admin
have 24 CPUs machine and write 200MB to buffer_size_kb, the system
consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is
usually unacceptable.

Fortunatelly, almost all users don't use max latency feature.
The max latency buffer can be disabled easily.

This patch shrink buffer size of the max latency buffer if
unnecessary.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-21 10:20:17 -04:00
Lai Jiangshan
bc289ae98b tracing: Reduce latency and remove percpu trace_seq
__print_flags() and __print_symbolic() use percpu trace_seq:

1) Its memory is allocated at compile time, it wastes memory if we don't use tracing.
2) It is percpu data and it wastes more memory for multi-cpus system.
3) It disables preemption when it executes its core routine
   "trace_seq_printf(s, "%s: ", #call);" and introduces latency.

So we move this trace_seq to struct trace_iterator.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4C078350.7090106@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-20 22:05:34 -04:00
Richard Kennedy
985023dee6 trace: Reorder struct ring_buffer_per_cpu to remove padding on 64bit
Reorder structure to remove 8 bytes of padding on 64 bit builds.
This shrinks the size to 128 bytes so allowing allocation from a smaller
slab & needed one fewer cache lines.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
LKML-Reference: <1269516456.2054.8.camel@localhost>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-20 21:58:44 -04:00
Li Zefan
e870e9a124 tracing: Allow to disable cmdline recording
We found that even enabling a single trace event that will rarely be
triggered can add big overhead to context switch.

(lmbench context switch test)
 -------------------------------------------------
 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K
 ctxsw  ctxsw  ctxsw ctxsw  ctxsw   ctxsw   ctxsw
------ ------ ------ ------ ------ ------- -------
  2.19   2.3   2.21   2.56   2.13     2.54    2.07
  2.39   2.51  2.35   2.75   2.27     2.81    2.24

The overhead is 6% ~ 11%.

It's because when a trace event is enabled 3 tracepoints (sched_switch,
sched_wakeup, sched_wakeup_new) will be activated to map pid to cmdname.

We'd like to avoid this overhead, so add a trace option '(no)record-cmd'
to allow to disable cmdline recording.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4C2D57F4.2050204@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-20 21:52:33 -04:00
Arnd Bergmann
b444786f1a tracing: Use generic_file_llseek for debugfs
The default for llseek will change to no_llseek,
so the tracing debugfs files need to add explicit
.llseek assignments. Since we're dealing with regular
files from a VFS perspective, use generic_file_llseek.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: John Kacur <jkacur@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <1278538820-1392-10-git-send-email-arnd@arndb.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-07-20 14:31:24 +02:00
Frederic Weisbecker
eb7beb5c09 tracing: Remove special traces
Special traces type was only used by sysprof. Lets remove it now
that sysprof ftrace plugin has been dropped.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Soeren Sandmann <sandmann@daimi.au.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
2010-07-20 14:31:07 +02:00
Frederic Weisbecker
f376bf5ffb tracing: Remove sysprof ftrace plugin
The sysprof ftrace plugin doesn't seem to be seriously used
somewhere. There is a branch in the sysprof tree that makes
an interface to it, but the real sysprof tool uses either its
own module or perf events.

Drop the sysprof ftrace plugin then, as it's mostly useless.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Soeren Sandmann <sandmann@daimi.au.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
2010-07-20 14:29:46 +02:00
Catalin Marinas
9078370c0d kmemleak: Add support for NO_BOOTMEM configurations
With commits 08677214 and 59be5a8e, alloc_bootmem()/free_bootmem() and
friends use the early_res functions for memory management when
NO_BOOTMEM is enabled. This patch adds the kmemleak calls in the
corresponding code paths for bootmem allocations.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: stable@kernel.org
2010-07-19 11:54:15 +01:00
Frederic Weisbecker
5d550467b9 tracing: Remove ksym tracer
The ksym (breakpoint) ftrace plugin has been superseded by perf
tools that are much more poweful to use the cpu breakpoints.
This tracer doesn't bring more feature. It has been deprecated
for a while now, lets remove it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-07-15 23:59:33 +02:00
Ingo Molnar
8bd0e1be25 Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 into perf/core 2010-07-06 09:00:32 +02:00
Masami Hiramatsu
e09c8614b3 tracing/kprobes: Support "string" type
Support string type tracing and printing in kprobe-tracer.

This allows user to trace string data in kernel including __user data. Note
that sometimes __user data may not be accessed if it is paged-out (sorry, but
kprobes operation should be done in atomic, we can not wait for page-in).

Commiter note: Fixed up conflicts with b7e2ece.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100519195724.2885.18788.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-07-05 15:54:45 -03:00
Ingo Molnar
08f8ba0799 Merge commit 'v2.6.35-rc4' into perf/core
Merge reason: Pick up the latest perf fixes

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-07-05 08:30:58 +02:00
Yehuda Sadeh
ff49d74ad3 module: initialize module dynamic debug later
We should initialize the module dynamic debug datastructures
only after determining that the module is not loaded yet. This
fixes a bug that introduced in 2.6.35-rc2, where when a trying
to load a module twice, we also load it's dynamic printing data
twice which causes all sorts of nasty issues. Also handle
the dynamic debug cleanup later on failure.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed a #ifdef)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-07-04 20:17:22 -07:00
Linus Torvalds
123f94f22e 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: Cure nr_iowait_cpu() users
  init: Fix comment
  init, sched: Fix race between init and kthreadd
2010-07-02 09:52:58 -07:00
Peter Zijlstra
8c215bd389 sched: Cure nr_iowait_cpu() users
Commit 0224cf4c5e (sched: Intoduce get_cpu_iowait_time_us())
broke things by not making sure preemption was indeed disabled
by the callers of nr_iowait_cpu() which took the iowait value of
the current cpu.

This resulted in a heap of preempt warnings. Cure this by making
nr_iowait_cpu() take a cpu number and fix up the callers to pass
in the right number.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-pm@lists.linux-foundation.org
LKML-Reference: <1277968037.1868.120.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-07-01 09:39:48 +02:00
Michal Hocko
7a0ea09ad5 futex: futex_find_get_task remove credentails check
futex_find_get_task is currently used (through lookup_pi_state) from two
contexts, futex_requeue and futex_lock_pi_atomic.  None of the paths
looks it needs the credentials check, though.  Different (e)uids
shouldn't matter at all because the only thing that is important for
shared futex is the accessibility of the shared memory.

The credentail check results in glibc assert failure or process hang (if
glibc is compiled without assert support) for shared robust pthread
mutex with priority inheritance if a process tries to lock already held
lock owned by a process with a different euid:

pthread_mutex_lock.c:312: __pthread_mutex_lock_full: Assertion `(-(e)) != 3 || !robust' failed.

The problem is that futex_lock_pi_atomic which is called when we try to
lock already held lock checks the current holder (tid is stored in the
futex value) to get the PI state.  It uses lookup_pi_state which in turn
gets task struct from futex_find_get_task.  ESRCH is returned either
when the task is not found or if credentials check fails.

futex_lock_pi_atomic simply returns if it gets ESRCH.  glibc code,
however, doesn't expect that robust lock returns with ESRCH because it
should get either success or owner died.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Darren Hart <dvhltc@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-30 15:43:44 -07:00
Pavan Naregundi
e05bd3367b kexec: fix Oops in crash_shrink_memory()
When crashkernel is not enabled, "echo 0 > /sys/kernel/kexec_crash_size"
OOPSes the kernel in crash_shrink_memory.  This happens when
crash_shrink_memory tries to release the 'crashk_res' resource which are
not reserved.  Also value of "/sys/kernel/kexec_crash_size" shows as 1,
which should be 0.

This patch fixes the OOPS in crash_shrink_memory and shows
"/sys/kernel/kexec_crash_size" as 0 when crash kernel memory is not
reserved.

Signed-off-by: Pavan Naregundi <pavan@linux.vnet.ibm.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-29 15:29:31 -07:00
Steven Rostedt
a1d0ce8213 tracing: Use class->reg() for all registering of events
Because kprobes and syscalls need special processing to register
events, the class->reg() method was created to handle the differences.

But instead of creating a default ->reg for perf and ftrace events,
the code was scattered with:

	if (class->reg)
		class->reg();
	else
		default_reg();

This is messy and can also lead to bugs.

This patch cleans up this code and creates a default reg() entry for
the events allowing for the code to directly call the class->reg()
without the condition.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 21:13:14 -04:00
Chase Douglas
d62f85d1e2 tracing/function-graph: Use correct string size for snprintf
The nsecs_str string is a local variable defined as:

char nsecs_str[5];

It is possible for the snprintf call to use a size value larger than the
size of the string. This should not cause a buffer overrun as it is
written now due to the value for the string format "%03lu" can not be
larger than 1000. However, this change makes it correct. By making the
size correct we guard against potential future changes that could actually
cause a buffer overrun.

Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
LKML-Reference: <1276619355-18116-1-git-send-email-chase.douglas@canonical.com>

[ added 'UL' to number 8 to fix gcc warning comparing it to sizeof() ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 21:11:39 -04:00
Li Zefan
67ead0a6ce tracing: Remove open-coded __trace_add_event_call()
Let trace_module_add_events() and event_trace_init() call
__trace_add_event_call().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BFA37E9.1020106@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 17:12:55 -04:00
Li Zefan
ffb9f99528 tracing: Remove redundant raw_init callbacks
raw_init callback is optional.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BFA37D4.7070500@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 17:12:53 -04:00
Li Zefan
c9d932cf8a tracing: Remove test of NULL define_fields callback
Every event (or event class) has it's define_fields callback,
so the test is redundant.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BFA37BC.8080707@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 17:12:52 -04:00
Li Zefan
8728fe501e tracing: Don't allocate common fields for every trace events
Every event has the same common fields, so it's a big waste of
memory to have a copy of those fields for every event.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BFA3759.30105@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 17:12:46 -04:00
Li Zefan
c9642c49aa tracing: Use a global field list for all syscall exit events
All syscall exit events have the same fields.

The kernel size drops 2.5K:

   text    data     bss     dec     hex filename
7018612 2034376 7251132 16304120         f8c7f8 vmlinux.o.orig
7018612 2031888 7251132 16301632         f8be40 vmlinux.o

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BFA3746.8070100@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 17:12:44 -04:00
Thomas Gleixner
f384c954c9 Merge branch 'linus' into perf/core
Reason: Further changes conflict with upstream fixes

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-06-28 22:33:24 +02:00
Linus Torvalds
5904b3b81d 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:
  tracing: Fix undeclared ENOSYS in include/linux/tracepoint.h
  perf record: prevent kill(0, SIGTERM);
  perf session: Remove threads from tree on PERF_RECORD_EXIT
  perf/tracing: Fix regression of perf losing kprobe events
  perf_events: Fix Intel Westmere event constraints
  perf record: Don't call newt functions when not initialized
2010-06-28 12:24:43 -07:00
Linus Torvalds
f3866db8f7 Merge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq: Deal with desc->set_type() changing desc->chip
2010-06-28 12:23:12 -07:00
Linus Torvalds
f014d937d6 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: Prevent compiler from optimising the sched_avg_update() loop
  sched: Fix over-scheduling bug
  sched: Fix PROVE_RCU vs cpu_cgroup
2010-06-28 12:18:30 -07:00
Linus Torvalds
cf91b415c8 Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  nohz: Fix nohz ratelimit
2010-06-28 12:18:02 -07:00
Linus Torvalds
e6cb6281ef Merge branch 'core-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:
  sched: silence PROVE_RCU in sched_fork()
  idr: fix RCU lockdep splat in idr_get_next()
  rcu: apply RCU protection to wake_affine()
2010-06-28 12:17:40 -07:00
Will Deacon
0d98bb2656 sched: Prevent compiler from optimising the sched_avg_update() loop
GCC 4.4.1 on ARM has been observed to replace the while loop in
sched_avg_update with a call to uldivmod, resulting in the
following build failure at link-time:

kernel/built-in.o: In function `sched_avg_update':
 kernel/sched.c:1261: undefined reference to `__aeabi_uldivmod'
 kernel/sched.c:1261: undefined reference to `__aeabi_uldivmod'
make: *** [.tmp_vmlinux1] Error 1

This patch introduces a fake data hazard to the loop body to
prevent the compiler optimising the loop away.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-25 16:11:50 +02:00
Frederic Weisbecker
45a73372ef hw_breakpoints: Fix per task breakpoint tracking
Freeing a perf event can happen in several ways. A task
calls perf_event_exit_task() right before exiting. This helper
will detach all the events from the task context and queue their
removal through free_event() if they are child tasks. The task
also loses its context reference there.

Releasing the breakpoint slot from the constraint table is made
from free_event() that calls release_bp_slot(). We count the number
of breakpoints this task is running by looking at the task's
perf_event_ctxp and iterating through its attached events.
But at this time, the reference to this context has been cleaned up
already.

So looking at the event->ctx instead of task->perf_event_ctxp
to count the remaining breakpoints should solve the problem.
At least it would for child breakpoints, but not for parent ones.
If the parent exits before the child, it will remove all its
events from the context but free_event() will be called later,
on fd release time. And checking the number of breakpoints the
task has attached to its context at this time is unreliable as all
events have been removed from the context.

To solve this, we keep track of the list of per task breakpoints.
On top of it, we maintain our array of numbers of breakpoints used
by the tasks. We use the context address as a task id.

So, instead of looking at the number of events attached to a context,
we walk through our list of per task breakpoints and count the number
of breakpoints that use the same ctx than the one to be reserved or
released from the constraint table, and update the count on top of this
result.

In the meantime it solves a bad refcounting, it also solves a warning,
reported by Paul.

Badness at /home/paulus/kernel/perf/kernel/hw_breakpoint.c:114
NIP: c0000000000cb470 LR: c0000000000cb46c CTR: c00000000032d9b8
REGS: c000000118e7b570 TRAP: 0700   Not tainted  (2.6.35-rc3-perf-00008-g76b0f13
)
MSR: 9000000000029032 <EE,ME,CE,IR,DR>  CR: 44004424  XER: 000fffff
TASK = c0000001187dcad0[3143] 'perf' THREAD: c000000118e78000 CPU: 1
GPR00: c0000000000cb46c c000000118e7b7f0 c0000000009866a0 0000000000000020
GPR04: 0000000000000000 000000000000001d 0000000000000000 0000000000000001
GPR08: c0000000009bed68 c00000000086dff8 c000000000a5bf10 0000000000000001
GPR12: 0000000024004422 c00000000ffff200 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000018 00000000101150f4
GPR20: 0000000010206b40 0000000000000000 0000000000000000 00000000101150f4
GPR24: c0000001199090c0 0000000000000001 0000000000000000 0000000000000001
GPR28: 0000000000000000 0000000000000000 c0000000008ec290 0000000000000000
NIP [c0000000000cb470] .task_bp_pinned+0x5c/0x12c
LR [c0000000000cb46c] .task_bp_pinned+0x58/0x12c
Call Trace:
[c000000118e7b7f0] [c0000000000cb46c] .task_bp_pinned+0x58/0x12c (unreliable)
[c000000118e7b8a0] [c0000000000cb584] .toggle_bp_task_slot+0x44/0xe4
[c000000118e7b940] [c0000000000cb6c8] .toggle_bp_slot+0xa4/0x164
[c000000118e7b9f0] [c0000000000cbafc] .release_bp_slot+0x44/0x6c
[c000000118e7ba80] [c0000000000c4178] .bp_perf_event_destroy+0x10/0x24
[c000000118e7bb00] [c0000000000c4aec] .free_event+0x180/0x1bc
[c000000118e7bbc0] [c0000000000c54c4] .perf_event_release_kernel+0x14c/0x170

Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
2010-06-24 23:33:40 +02:00
Peter Zijlstra
8695159967 sched: silence PROVE_RCU in sched_fork()
Because cgroup_fork() is ran before sched_fork() [ from copy_process() ]
and the child's pid is not yet visible the child is pinned to its
cgroup. Therefore we can silence this warning.

A nicer solution would be moving cgroup_fork() to right after
dup_task_struct() and exclude PF_STARTING from task_subsys_state().

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-06-23 15:14:09 -07:00
Daniel J Blueman
f3b577dec1 rcu: apply RCU protection to wake_affine()
The task_group() function returns a pointer that must be protected
by either RCU, the ->alloc_lock, or the cgroup lock (see the
rcu_dereference_check() in task_subsys_state(), which is invoked by
task_group()).  The wake_affine() function currently does none of these,
which means that a concurrent update would be within its rights to free
the structure returned by task_group().  Because wake_affine() uses this
structure only to compute load-balancing heuristics, there is no reason
to acquire either of the two locks.

Therefore, this commit introduces an RCU read-side critical section that
starts before the first call to task_group() and ends after the last use
of the "tg" pointer returned from task_group().  Thanks to Li Zefan for
pointing out the need to extend the RCU read-side critical section from
that proposed by the original patch.

Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-06-23 06:50:44 -07:00
Ingo Molnar
646b1db495 Merge commit 'v2.6.35-rc3' into perf/core
Merge reason: Go from -rc1 base to -rc3 base, merge in fixes.
2010-06-18 10:53:19 +02:00
Alex,Shi
3c93717cfa sched: Fix over-scheduling bug
Commit e70971591 ("sched: Optimize unused cgroup configuration") introduced
an imbalanced scheduling bug.

If we do not use CGROUP, function update_h_load won't update h_load. When the
system has a large number of tasks far more than logical CPU number, the
incorrect cfs_rq[cpu]->h_load value will cause load_balance() to pull too
many tasks to the local CPU from the busiest CPU. So the busiest CPU keeps
going in a round robin. That will hurt performance.

The issue was found originally by a scientific calculation workload that
developed by Yanmin. With that commit, the workload performance drops
about 40%.

 CPU  before    after

 00   : 2       : 7
 01   : 1       : 7
 02   : 11      : 6
 03   : 12      : 7
 04   : 6       : 6
 05   : 11      : 7
 06   : 10      : 6
 07   : 12      : 7
 08   : 11      : 6
 09   : 12      : 6
 10   : 1       : 6
 11   : 1       : 6
 12   : 6       : 6
 13   : 2       : 6
 14   : 2       : 6
 15   : 1       : 6

Reviewed-by: Yanmin zhang <yanmin.zhang@intel.com>
Signed-off-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1276754893.9452.5442.camel@debian>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-18 10:45:25 +02:00
Peter Zijlstra
3310d4d38f nohz: Fix nohz ratelimit
Chris Wedgwood reports that 39c0cbe (sched: Rate-limit nohz) causes a
serial console regression, unresponsiveness, and indeed it does. The
reason is that the nohz code is skipped even when the tick was already
stopped before the nohz_ratelimit(cpu) condition changed.

Move the nohz_ratelimit() check to the other conditions which prevent
long idle sleeps.

Reported-by: Chris Wedgwood <cw@f00f.org>
Tested-by: Brian Bloniarz <bmb@athenacr.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg KH <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Jef Driesen <jefdriesen@telenet.be>
LKML-Reference: <1276790557.27822.516.camel@twins>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-06-17 19:37:29 +02:00
Len Brown
42de5532f4 Merge branch 'bugzilla-13931-sleep-nvs' into release
Conflicts:
	drivers/acpi/sleep.c

Signed-off-by: Len Brown <len.brown@intel.com>
2010-06-12 01:15:40 -04:00
Steven Rostedt
a8fb260805 perf/tracing: Fix regression of perf losing kprobe events
With the addition of the code to shrink the kernel tracepoint
infrastructure, we lost kprobes being traced by perf. The reason
is that I tested if the "tp_event->class->perf_probe" existed before
enabling it. This prevents "ftrace only" events (like the function
trace events) from being enabled by perf.

Unfortunately, kprobe events do not use perf_probe. This causes
kprobes to be missed by perf. To fix this, we add the test to
see if "tp_event->class->reg" exists as well as perf_probe.

Normal trace events have only "perf_probe" but no "reg" function,
and kprobes and syscalls have the "reg" but no "perf_probe".
The ftrace unique events do not have either, so this is a valid
test. If a kprobe or syscall is not to be probed by perf, the
"reg" function is called anyway, and will return a failure and
prevent perf from probing it.

Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-10 20:56:54 -04:00
Linus Torvalds
85ca7886f5 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:
  tracing: Fix null pointer deref with SEND_SIG_FORCED
  perf: Fix signed comparison in perf_adjust_period()
  powerpc/oprofile: fix potential buffer overrun in op_model_cell.c
  perf symbols: Set the DSO long name when using symbol_conf.vmlinux_name
2010-06-10 09:30:09 -07:00
Matthew Garrett
dd4c4f17d7 suspend: Move NVS save/restore code to generic suspend functionality
Saving platform non-volatile state may be required for suspend to RAM as
well as hibernation. Move it to more generic code.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-06-10 11:02:34 -04:00
Ingo Molnar
c726b61c6a Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core 2010-06-09 18:55:57 +02:00
Li Zefan
039ca4e74a tracing: Remove kmemtrace ftrace plugin
We have been resisting new ftrace plugins and removing existing
ones, and kmemtrace has been superseded by kmem trace events
and perf-kmem, so we remove it.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
[ remove kmemtrace from the makefile, handle slob too ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-06-09 17:31:22 +02:00
Thomas Gleixner
4673247562 genirq: Deal with desc->set_type() changing desc->chip
The set_type() function can change the chip implementation when the
trigger mode changes. That might result in using an non-initialized
irq chip when called from __setup_irq() or when called via
set_irq_type() on an already enabled irq. 

The set_irq_type() function should not be called on an enabled irq,
but because we forgot to put a check into it, we have a bunch of users
which grew the habit of doing that and it never blew up as the
function is serialized via desc->lock against all users of desc->chip
and they never hit the non-initialized irq chip issue.

The easy fix for the __setup_irq() issue would be to move the
irq_chip_set_defaults(desc->chip) call after the trigger setting to
make sure that a chip change is covered.

But as we have already users, which do the type setting after
request_irq(), the safe fix for now is to call irq_chip_set_defaults()
from __irq_set_trigger() when desc->set_type() changed the irq chip.

It needs a deeper analysis whether we should refuse to change the chip
on an already enabled irq, but that'd be a large scale change to fix
all the existing users. So that's neither stable nor 2.6.35 material.

Reported-by: Esben Haabendal <eha@doredevelopment.dk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>
Cc: stable@kernel.org
2010-06-09 17:05:08 +02:00
Peter Zijlstra
e78505958c perf: Convert perf_event to local_t
Since now all modification to event->count (and ->prev_count
and ->period_left) are local to a cpu, change then to local64_t so we
avoid the LOCK'ed ops.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-09 11:12:37 +02:00