From: Ingo Molnar Date: Sun, 14 Oct 2012 12:28:50 +0000 (+0200) Subject: sched: Add WAKEUP_PREEMPTION feature flag, on by default X-Git-Tag: v3.8-rc1~169^2~2^2~4^2~1 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=8ed92e51f99c2199c64cb33b4ba95ab12940a94c;p=~emulex%2Finfiniband.git 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 --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6b800a14b99..f936552b3db 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 eebefcad702..e68e69ab917 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 */