Messages in this thread | | | Subject | Re: [patch 01/15] sched: (fixlet) dont update shares twice on on_rq parent | From | Mike Galbraith <> | Date | Tue, 10 May 2011 10:32:06 +0200 |
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On Tue, 2011-05-10 at 16:14 +0900, Hidetoshi Seto wrote: > (2011/05/03 18:28), Paul Turner wrote: > > In dequeue_task_fair() we bail on dequeue when we encounter a parenting entity > > with additional weight. However, we perform a double shares update on this > > entity since we continue the shares update traversal from that point, despite > > dequeue_entity() having already updated its queuing cfs_rq. > > > > Avoid this by starting from the parent when we resume. > > > > Signed-off-by: Paul Turner <pjt@google.com> > > --- > > kernel/sched_fair.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > Index: tip/kernel/sched_fair.c > > =================================================================== > > --- tip.orig/kernel/sched_fair.c > > +++ tip/kernel/sched_fair.c > > @@ -1355,8 +1355,10 @@ static void dequeue_task_fair(struct rq > > dequeue_entity(cfs_rq, se, flags); > > > > /* Don't dequeue parent if it has other entities besides us */ > > - if (cfs_rq->load.weight) > > + if (cfs_rq->load.weight) { > > + se = parent_entity(se); > > break; > > + } > > flags |= DEQUEUE_SLEEP; > > } > > > > Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> > > This small fixlet can stand alone. > Peter, how about getting this into git tree first?
tip 2f36825b176f67e5c5228aa33d828bc39718811f contains the below.
/* Don't dequeue parent if it has other entities besides us */ - if (cfs_rq->load.weight) + if (cfs_rq->load.weight) { + /* + * Bias pick_next to pick a task from this cfs_rq, as + * p is sleeping when it is within its sched_slice. + */ + if (task_sleep && parent_entity(se)) + set_next_buddy(parent_entity(se)); break; + } flags |= DEQUEUE_SLEEP; }
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