On Wed, Jul 22, 2015 at 02:51:01PM +0800, Leo Yan wrote: > On Tue, Jul 07, 2015 at 07:23:54PM +0100, Morten Rasmussen wrote: > > Tasks being dequeued for the last time (state == TASK_DEAD) are dequeued > > with the DEQUEUE_SLEEP flag which causes their load and utilization > > contributions to be added to the runqueue blocked load and utilization. > > Hence they will contain load or utilization that is gone away. The issue > > only exists for the root cfs_rq as cgroup_exit() doesn't set > > DEQUEUE_SLEEP for task group exits. > > > > If runnable+blocked load is to be used as a better estimate for cpu > > load the dead task contributions need to be removed to prevent > > load_balance() (idle_balance() in particular) from over-estimating the > > cpu load. > > > > cc: Ingo Molnar <[email protected]> > > cc: Peter Zijlstra <[email protected]> > > > > Signed-off-by: Morten Rasmussen <[email protected]> > > --- > > kernel/sched/fair.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 775b0c7..fa12ce5 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -3217,6 +3217,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct > > sched_entity *se, int flags) > > * Update run-time statistics of the 'current'. > > */ > > update_curr(cfs_rq); > > + if (entity_is_task(se) && task_of(se)->state == TASK_DEAD) > > + flags &= !DEQUEUE_SLEEP; > > So flags will be set to zero? Could be replaced by "flags &= ~DEQUEUE_SLEEP"?
Not could, should :) I meant to clear the flag, but used the wrong operator. We only have DEQUEUE_SLEEP and 0 at the moment so it doesn't matter, but it might later. Thanks, Morten -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
