From 8ed92e51f99c2199c64cb33b4ba95ab12940a94c Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 14 Oct 2012 14:28:50 +0200 Subject: [PATCH] sched: Add WAKEUP_PREEMPTION feature flag, on by default As per the recent discussion with Mike and Linus, make it easier to test with/without this feature. No change in default behavior. Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Linus Torvalds Link: http://lkml.kernel.org/n/tip-izoxq4haeg4mTognnDbwcevt@git.kernel.org --- kernel/sched/fair.c | 2 +- kernel/sched/features.h | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6b800a14b990..f936552b3db1 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2907,7 +2907,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ * Batch and idle tasks do not preempt non-idle tasks (their preemption * is driven by the tick): */ - if (unlikely(p->policy != SCHED_NORMAL)) + if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION)) return; find_matching_se(&se, &pse); diff --git a/kernel/sched/features.h b/kernel/sched/features.h index eebefcad7027..e68e69ab917d 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -31,6 +31,11 @@ SCHED_FEAT(LAST_BUDDY, true) */ SCHED_FEAT(CACHE_HOT_BUDDY, true) +/* + * Allow wakeup-time preemption of the current task: + */ +SCHED_FEAT(WAKEUP_PREEMPTION, true) + /* * Use arch dependent cpu power functions */ -- 2.30.2