Commit e03a9a55 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

perf: Change close() semantics for group events

In order to always call list_del_event() on the correct cpu if the
event is part of an active context and avoid having to do two IPIs,
change the close() semantics slightly.

The current perf_event_disable() call would disable a whole group if
the event that's being closed is the group leader, whereas the new
code keeps the group siblings enabled.

People should not rely on this behaviour and I don't think they do,
but in case we find they do, the fix is easy and we have to take the
double IPI cost.
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vince Weaver <vweaver1@eecs.utk.edu>
Link: http://lkml.kernel.org/r/20110409192142.038377551@chello.nlSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent dce5855b
......@@ -2920,12 +2920,6 @@ int perf_event_release_kernel(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
/*
* Remove from the PMU, can't get re-enabled since we got
* here because the last ref went.
*/
perf_event_disable(event);
WARN_ON_ONCE(ctx->parent_ctx);
/*
* There are two ways this annotation is useful:
......@@ -2942,8 +2936,8 @@ int perf_event_release_kernel(struct perf_event *event)
mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
raw_spin_lock_irq(&ctx->lock);
perf_group_detach(event);
list_del_event(event, ctx);
raw_spin_unlock_irq(&ctx->lock);
perf_remove_from_context(event);
mutex_unlock(&ctx->mutex);
free_event(event);
......
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