Commit 0b9ca2dc authored by Vincent Guittot's avatar Vincent Guittot Committed by Peter Zijlstra
Browse files

sched/fair: Always trigger resched at the end of a protected period 



Always trigger a resched after a protected period even if the entity is
still eligible. It can happen that an entity remains eligible at the end
of the protected period but must let an entity with a shorter slice to run
in order to keep its lag shorter than slice. This is particulalry true
with run to parity which tries to maximize the lag.

Signed-off-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250708165630.1948751-7-vincent.guittot@linaro.org
parent 3a0baa8e

kernel/sched/fair.c

+1 −9
Original line number Diff line number Diff line
@@ -1182,14 +1182,6 @@ static inline void update_curr_task(struct task_struct *p, s64 delta_exec) 
	cgroup_account_cputime(p, delta_exec);

}



static inline bool resched_next_slice(struct cfs_rq *cfs_rq, struct sched_entity *curr)

{

	if (protect_slice(curr))

		return false;



	return !entity_eligible(cfs_rq, curr);

}



/*

 * Used by other classes to account runtime.

 */
@@ -1250,7 +1242,7 @@ static void update_curr(struct cfs_rq *cfs_rq) 
	if (cfs_rq->nr_queued == 1)

		return;



	if (resched || resched_next_slice(cfs_rq, curr)) {

	if (resched || !protect_slice(curr)) {

		resched_curr_lazy(rq);

		clear_buddies(cfs_rq, curr);

	}