Commit 95246d1e authored by Vincent Guittot's avatar Vincent Guittot Committed by Peter Zijlstra
Browse files

sched/pelt: Relax the sync of runnable_sum with runnable_avg 



Similarly to util_avg and util_sum, don't sync runnable_sum with the low
bound of runnable_avg but only ensure that runnable_sum stays in the
correct range.

Signed-off-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarDietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: default avatarSachin Sant <sachinp@linux.ibm.com>
Link: https://lkml.kernel.org/r/20220111134659.24961-4-vincent.guittot@linaro.org
parent 7ceb7710

kernel/sched/fair.c

+19 −14
Original line number Diff line number Diff line
@@ -3483,11 +3483,11 @@ update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq 
static inline void

update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)

{

	long delta = gcfs_rq->avg.runnable_avg - se->avg.runnable_avg;

	u32 divider;

	long delta_sum, delta_avg = gcfs_rq->avg.runnable_avg - se->avg.runnable_avg;

	u32 new_sum, divider;



	/* Nothing to update */

	if (!delta)

	if (!delta_avg)

		return;



	/*
@@ -3498,11 +3498,16 @@ update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cf 


	/* Set new sched_entity's runnable */

	se->avg.runnable_avg = gcfs_rq->avg.runnable_avg;

	se->avg.runnable_sum = se->avg.runnable_avg * divider;

	new_sum = se->avg.runnable_avg * divider;

	delta_sum = (long)new_sum - (long)se->avg.runnable_sum;

	se->avg.runnable_sum = new_sum;



	/* Update parent cfs_rq runnable */

	add_positive(&cfs_rq->avg.runnable_avg, delta);

	cfs_rq->avg.runnable_sum = cfs_rq->avg.runnable_avg * divider;

	add_positive(&cfs_rq->avg.runnable_avg, delta_avg);

	add_positive(&cfs_rq->avg.runnable_sum, delta_sum);

	/* See update_cfs_rq_load_avg() */

	cfs_rq->avg.runnable_sum = max_t(u32, cfs_rq->avg.runnable_sum,

					      cfs_rq->avg.runnable_avg * PELT_MIN_DIVIDER);

}



static inline void
@@ -3702,7 +3707,10 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) 


		r = removed_runnable;

		sub_positive(&sa->runnable_avg, r);

		sa->runnable_sum = sa->runnable_avg * divider;

		sub_positive(&sa->runnable_sum, r * divider);

		/* See sa->util_sum above */

		sa->runnable_sum = max_t(u32, sa->runnable_sum,

					      sa->runnable_avg * PELT_MIN_DIVIDER);



		/*

		 * removed_runnable is the unweighted version of removed_load so we
@@ -3789,12 +3797,6 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s 
 */

static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)

{

	/*

	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.

	 * See ___update_load_avg() for details.

	 */

	u32 divider = get_pelt_divider(&cfs_rq->avg);



	dequeue_load_avg(cfs_rq, se);

	sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg);

	sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum);
@@ -3803,7 +3805,10 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s 
					  cfs_rq->avg.util_avg * PELT_MIN_DIVIDER);



	sub_positive(&cfs_rq->avg.runnable_avg, se->avg.runnable_avg);

	cfs_rq->avg.runnable_sum = cfs_rq->avg.runnable_avg * divider;

	sub_positive(&cfs_rq->avg.runnable_sum, se->avg.runnable_sum);

	/* See update_cfs_rq_load_avg() */

	cfs_rq->avg.runnable_sum = max_t(u32, cfs_rq->avg.runnable_sum,

					      cfs_rq->avg.runnable_avg * PELT_MIN_DIVIDER);



	add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum);