From ba0d3bf5f97b74ee1cf8ea6cc35efe5a052514a4 Mon Sep 17 00:00:00 2001 From: Vincent Guittot Date: Wed, 24 Jun 2026 17:12:27 +0200 Subject: [PATCH] sched/eevdf: Cancel slice protection if short slice task is eligible If a short slice task will not be the next to be picked but is eligible, we cancel the slice protection to speedup the time when the short slice task will be the next to run. Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Tested-by: K Prateek Nayak Link: https://patch.msgid.link/20260624151229.1710703-5-vincent.guittot@linaro.org --- kernel/sched/fair.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index af207f03856d..9046b2ea68c6 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9859,18 +9859,13 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f cse_is_idle = se_is_idle(se); pse_is_idle = se_is_idle(pse); + nse = se; /* * Preempt an idle entity in favor of a non-idle entity (and don't preempt * in the inverse case). */ - if (cse_is_idle && !pse_is_idle) { - /* - * When non-idle entity preempt an idle entity, - * don't give idle entity slice protection. - */ - preempt_action = PREEMPT_WAKEUP_SHORT; + if (cse_is_idle && !pse_is_idle) goto preempt; - } if (cse_is_idle != pse_is_idle) return; @@ -9933,16 +9928,23 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f goto preempt; } + /* + * If @p is eligible but not the next task to run then cancel protection + * to prevent large scheduling latency + */ + if (preempt_action == PREEMPT_WAKEUP_SHORT && entity_eligible(cfs_rq, pse)) + goto preempt; + if (sched_feat(RUN_TO_PARITY)) update_protect_slice(cfs_rq, se); return; preempt: - if (preempt_action == PREEMPT_WAKEUP_SHORT) { - cancel_protect_slice(se); + cancel_protect_slice(se); + + if (preempt_action == PREEMPT_WAKEUP_SHORT) set_short_buddy(cfs_rq, pse); - } resched_curr_lazy(rq); }