linux-toradex.git/kernel/perf_event.c, branch v2.6.39-rc7

perf_event: Fix cgrp event scheduling bug in perf_enable_on_exec()

2011-04-11T09:07:55+00:00

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 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20110406005454.GA1062@quad
Signed-off-by: Ingo Molnar

perf: Fix task_struct reference leak

2011-03-31T11:02:56+00:00

sys_perf_event_open() had an imbalance in the number of task refs it
took causing memory leakage

Cc: Jiri Olsa 
Cc: Oleg Nesterov 
Cc: stable@kernel.org # .37+
Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

perf: Rebase max unprivileged mlock threshold on top of page size

2011-03-31T11:02:54+00:00

Ensure we allow 512 kiB + 1 page for user control without
assuming a 4096 bytes page size.

Reported-by: Peter Zijlstra 
Signed-off-by: Frederic Weisbecker 
Signed-off-by: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Paul Mackerras 
Cc: Stephane Eranian 
Cc: 
LKML-Reference: <1301535209-9679-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar

perf: Better fit max unprivileged mlock pages for tools needs

2011-03-23T19:57:04+00:00

The maximum kilobytes of locked memory that an unprivileged user
can reserve is of 512 kB = 128 pages by default, scaled to the
number of onlined CPUs, which fits well with the tools that use
128 data pages by default.

However tools actually use 129 pages, because they need one more
for the user control page. Thus the default mlock threshold is
not sufficient for the default tools needs and we always end up
to evaluate the constant mlock rlimit policy, which doesn't have
this scaling with the number of online CPUs.

Hence, on systems that have more than 16 CPUs, we overlap the
rlimit threshold and fail to mmap:

	$ perf record ls
	Error: failed to mmap with 1 (Operation not permitted)

Just increase the max unprivileged mlock threshold by one page
so that it supports well perf tools even after 16 CPUs.

Reported-by: Han Pingtian 
Reported-by: Peter Zijlstra 
Reported-by: Arnaldo Carvalho de Melo 
Signed-off-by: Frederic Weisbecker 
Acked-by: Arnaldo Carvalho de Melo 
Cc: Stephane Eranian 
Cc: Stable 
LKML-Reference: <1300904979-5508-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar

perf_events: Fix stale ->cgrp pointer in update_cgrp_time_from_cpuctx()

2011-03-23T15:07:22+00:00

This patch solves a stale pointer problem in
update_cgrp_time_from_cpuctx(). The cpuctx->cgrp
was not cleared on all possible event exit paths,
including:

   close()
     perf_release()
       perf_release_kernel()
         list_del_event()

This patch fixes list_del_event() to clear cpuctx->cgrp
when there are no cgroup events left in the context.

[ This second version makes the code compile when
  CONFIG_CGROUP_PERF is not enabled. We unconditionally define
  perf_cpu_context->cgrp. ]

Signed-off-by: Stephane Eranian 
Cc: peterz@infradead.org
Cc: perfmon2-devel@lists.sf.net
Cc: paulus@samba.org
Cc: davem@davemloft.net
LKML-Reference: <20110323150306.GA1580@quad>
Signed-off-by: Ingo Molnar

perf: Fix tear-down of inherited group events

2011-03-16T13:04:14+00:00

When destroying inherited events, we need to destroy groups too,
otherwise the event iteration in perf_event_exit_task_context() will
miss group siblings and we leak events with all the consequences.

Reported-and-tested-by: Vince Weaver 
Signed-off-by: Peter Zijlstra 
Cc:  # .35+
LKML-Reference: <1300196470.2203.61.camel@twins>
Signed-off-by: Ingo Molnar

perf: Handle stopped state with tracepoints

2011-03-16T13:04:14+00:00

We toggle the state from start and stop callbacks but actually
don't check it when the event triggers. Do it so that
these callbacks actually work.

Signed-off-by: Frederic Weisbecker 
Cc: Arnaldo Carvalho de Melo 
Cc: Paul Mackerras 
Cc: Stephane Eranian 
Cc: 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1299529629-18280-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar

perf: Fix the software events state check

2011-03-16T13:04:13+00:00

Fix the mistakenly inverted check of events state.

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Paul Mackerras 
Cc: Stephane Eranian 
Cc: 
LKML-Reference: <1299529629-18280-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar

perf: Fix cgroup vs jump_label problem

2011-03-04T10:32:52+00:00

Li Zefan reported that the jump label code sleeps and we're calling it
under a spinlock, *fail* ;-)

Reported-by: Li Zefan 
Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

perf cgroup: Clean up perf_cgroup_create()

2011-03-04T10:32:51+00:00

- Use kzalloc() to replace kmalloc() + memset().

- Remove redundant initialization, since alloc_percpu() returns
  zero-filled percpu memory.

Signed-off-by: Li Zefan 
Acked-by: Stephane Eranian 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <4D6F347E.2010806@cn.fujitsu.com>
Signed-off-by: Ingo Molnar