Commit ab2ff007 authored Nov 25, 2014 by Srivatsa Vaddagiri

sched: update_rq_clock() must skip ONE update



Prevent large wakeup latencies from being accounted to the wrong task.

Change-Id: Ie9932acb8a733989441ff2dd51c50a2626cfe5c5
Cc: <stable@vger.kernel.org>
Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
CRs-Fixed: 755576
Patch-mainline: http://permalink.gmane.org/gmane.linux.kernel/1677324


Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>

parent 5d7a7415

kernel/sched/core.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -166,7 +166,12 @@ void update_rq_clock(struct rq *rq)
		{
		s64 delta;

		if (rq->skip_clock_update > 0)
		/*
		* Set during wakeup to indicate we are on the way to schedule().
		* Decrement to ensure that a very large latency is not accounted
		* to the wrong task.
		*/
		if (rq->skip_clock_update-- > 0)
		return;

		delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;