perf: Cure task_oncpu_function_call() races

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Oleg reported that on architectures with
__ARCH_WANT_INTERRUPTS_ON_CTXSW the IPI from
task_oncpu_function_call() can land before perf_event_task_sched_in()
and cause interesting situations for eg. perf_install_in_context().

This patch reworks the task_oncpu_function_call() interface to give a
more usable primitive as well as rework all its users to hopefully be
more obvious as well as remove the races.

While looking at the code I also found a number of races against
perf_event_task_sched_out() which can flip contexts between tasks so
plug those too.

Reported-and-reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

...

This commit is contained in:

Peter Zijlstra 2011-02-02 13:19:09 +01:00 • committed by Ingo Molnar

parent b84defe603

commit fe4b04fa31

3 changed files with 172 additions and 124 deletions

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7

include/linux/sched.h

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260

kernel/perf_event.c

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29

kernel/sched.c

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