On Mon, May 30, 2016 at 05:52:20PM +0200, Vincent Guittot wrote: > The cfs_rq->avg.last_update_time is initialize to 0 with the main effect > that the 1st sched_entity that will be attached, will keep its > last_update_time set to 0 and will attached once again during the > enqueue. > Initialize cfs_rq->avg.last_update_time to 1 instead. > > Signed-off-by: Vincent Guittot <vincent.guit...@linaro.org> > --- > > v3: > - add initialization of load_last_update_time_copy for not 64bits system > - move init into init_cfs_rq > > v2: > - rq_clock_task(rq_of(cfs_rq)) can't be used because lock is not held > > kernel/sched/fair.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 218f8e8..86be9c1 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8459,6 +8459,16 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) > cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; > #endif > #ifdef CONFIG_SMP > + /* > + * Set last_update_time to something different from 0 to make > + * sure the 1st sched_entity will not be attached twice: once > + * when attaching the task to the group and one more time when > + * enqueueing the task. > + */ > + cfs_rq->avg.last_update_time = 1; > +#ifndef CONFIG_64BIT > + cfs_rq->load_last_update_time_copy = 1; > +#endif > atomic_long_set(&cfs_rq->removed_load_avg, 0); > atomic_long_set(&cfs_rq->removed_util_avg, 0); > #endif
Then, when enqueued, both cfs_rq and task will be decayed to 0, due to a large gap between 1 and now, no?
