From d9aade7ae1d283097a3f626790e7c325a5c69007 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Wed, 22 Oct 2014 08:36:43 +0800 Subject: [PATCH] sched/deadline: Do not try to push tasks if pinned task switches to dl As Kirill mentioned (https://lkml.org/lkml/2013/1/29/118): | If rq has already had 2 or more pushable tasks and we try to add a | pinned task then call of push_rt_task will just waste a time. Just switched pinned task is not able to be pushed. If the rq has had several dl tasks before they have already been considered as candidates to be pushed (or pulled). This patch implements the same behavior as rt class which introduced by commit 10447917551e ("sched/rt: Do not try to push tasks if pinned task switches to RT"). Suggested-by: Kirill V Tkhai Acked-by: Juri Lelli Signed-off-by: Wanpeng Li Signed-off-by: Peter Zijlstra (Intel) Cc: Steven Rostedt Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1413938203-224610-1-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar --- kernel/sched/deadline.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 5285332392d5..9d1e76a21297 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1622,7 +1622,8 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) if (task_on_rq_queued(p) && rq->curr != p) { #ifdef CONFIG_SMP - if (rq->dl.overloaded && push_dl_task(rq) && rq != task_rq(p)) + if (p->nr_cpus_allowed > 1 && rq->dl.overloaded && + push_dl_task(rq) && rq != task_rq(p)) /* Only reschedule if pushing failed */ check_resched = 0; #endif /* CONFIG_SMP */ -- 2.20.1