From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Sat, 9 Apr 2011 19:17:48 +0000 (+0200)
Subject: perf: De-schedule a task context when removing the last event
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=64ce312618ef0e11d88def80effcefd1b59fdb1e;p=linux.git

perf: De-schedule a task context when removing the last event

Since perf_install_in_context() will now install a context when we
add the first event, we can de-schedule the context when the last
event is removed.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192142.090431763@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c378062da2772..cc5d57d1d0b66 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1120,6 +1120,10 @@ static int __perf_remove_from_context(void *info)
 	raw_spin_lock(&ctx->lock);
 	event_sched_out(event, cpuctx, ctx);
 	list_del_event(event, ctx);
+	if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
+		ctx->is_active = 0;
+		cpuctx->task_ctx = NULL;
+	}
 	raw_spin_unlock(&ctx->lock);
 
 	return 0;