sched: Fix ->min_vruntime calculation in dequeue_entity()
authorPeter Zijlstra <peterz@infradead.org>
Tue, 17 May 2011 23:21:10 +0000 (16:21 -0700)
committerIngo Molnar <mingo@elte.hu>
Sat, 28 May 2011 15:02:56 +0000 (17:02 +0200)
commit1e876231785d82443a5ac8b6c660e9f51bc5dede
treecab00c4c8ec3090a41215223dde2f47483287cb7
parentd6aa8f85f16379d42c147b22b59e33b67f9ff466
sched: Fix ->min_vruntime calculation in dequeue_entity()

Dima Zavin <dima@android.com> reported:

"After pulling the thread off the run-queue during a cgroup change,
the cfs_rq.min_vruntime gets recalculated. The dequeued thread's vruntime
then gets normalized to this new value. This can then lead to the thread
getting an unfair boost in the new group if the vruntime of the next
task in the old run-queue was way further ahead."

Reported-by: Dima Zavin <dima@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Recalls-having-tested-once-upon-a-time-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1305674470-23727-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/sched_fair.c