Daisuke Nishimura 4fc420c91f sched: Fix cgroup movement of forking process ... There is a small race between task_fork_fair() and sched_move_task(), which is trying to move the parent. task_fork_fair() sched_move_task() --------------------------------+--------------------------------- cfs_rq = task_cfs_rq(current) -> cfs_rq is the "old" one. curr = cfs_rq->curr -> curr is set to the parent. task_rq_lock() dequeue_task() ->parent.se.vruntime -= (old)cfs_rq->min_vruntime enqueue_task() ->parent.se.vruntime += (new)cfs_rq->min_vruntime task_rq_unlock() raw_spin_lock_irqsave(rq->lock) se->vruntime = curr->vruntime -> vruntime of the child is set to that of the parent which has already been updated by sched_move_task(). se->vruntime -= (old)cfs_rq->min_vruntime. raw_spin_unlock_irqrestore(rq->lock) As a result, vruntime of the child becomes far bigger than expected, if (new)cfs_rq->min_vruntime >> (old)cfs_rq->min_vruntime. This patch fixes this problem by setting "cfs_rq" and "curr" after holding the rq->lock. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20111215143655.662676b0.nishimura@mxp.nes.nec.co.jp Signed-off-by: Ingo Molnar <mingo@elte.hu>		2011-12-21 10:34:49 +01:00
..
auto_group.c
auto_group.h
clock.c
core.c	sched: Remove cfs bandwidth period check in tg_set_cfs_period()	2011-12-21 10:34:48 +01:00
cpupri.c
cpupri.h
debug.c
fair.c	sched: Fix cgroup movement of forking process	2011-12-21 10:34:49 +01:00
features.h
idle_task.c
Makefile
rt.c
sched.h	sched: Only queue remote wakeups when crossing cache boundaries	2011-12-21 10:34:44 +01:00
stats.c
stats.h	Merge branch 'sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into cputime-tip	2011-12-19 19:23:15 +01:00
stop_task.c