Commit 6d558c3a authored Jan 11, 2010 by Yong Zhang Committed by Ingo Molnar Jan 21, 2010

sched: Reassign prev and switch_count when reacquire_kernel_lock() fail



Assume A->B schedule is processing, if B have acquired BKL before and it
need reschedule this time. Then on B's context, it will go to
need_resched_nonpreemptible for reschedule. But at this time, prev and
switch_count are related to A. It's wrong and will lead to incorrect
scheduler statistics.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <2674af741001102238w7b0ddcadref00d345e2181d11@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 50b926e4

kernel/sched.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -5530,8 +5530,11 @@ need_resched_nonpreemptible:

		post_schedule(rq);

		if (unlikely(reacquire_kernel_lock(current) < 0))
		if (unlikely(reacquire_kernel_lock(current) < 0)) {
		prev = rq->curr;
		switch_count = &prev->nivcsw;
		goto need_resched_nonpreemptible;
		}

		preempt_enable_no_resched();
		if (need_resched())

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