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"? > dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP); > > update_stats_dequeue(cfs_rq, se); > -- > 1.9.1 > > -- > 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/ -- 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/
