From 0ea60c2054fc3b0c3eb68ac4f6884f3ee78d9925 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 11 Jun 2015 14:46:42 +0200 Subject: [PATCH] sched,dl: Remove return value from pull_dl_task() In order to be able to use pull_dl_task() from a callback, we need to do away with the return value. Since the return value indicates if we should reschedule, do this inside the function. Since not all callers currently do this, this can increase the number of reschedules due rt balancing. Too many reschedules is not a correctness issues, too few are. Signed-off-by: Peter Zijlstra (Intel) Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124742.859398977@infradead.org Signed-off-by: Thomas Gleixner --- kernel/sched/deadline.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index d80523fb1de5..079c09251e90 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -298,9 +298,8 @@ static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev) return false; } -static inline int pull_dl_task(struct rq *rq) +static inline void pull_dl_task(struct rq *rq) { - return 0; } static inline void queue_push_tasks(struct rq *rq) @@ -1041,7 +1040,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) resched_curr(rq); } -static int pull_dl_task(struct rq *this_rq); +static void pull_dl_task(struct rq *this_rq); #endif /* CONFIG_SMP */ @@ -1472,15 +1471,16 @@ static void push_dl_tasks(struct rq *rq) ; } -static int pull_dl_task(struct rq *this_rq) +static void pull_dl_task(struct rq *this_rq) { - int this_cpu = this_rq->cpu, ret = 0, cpu; + int this_cpu = this_rq->cpu, cpu; struct task_struct *p; + bool resched = false; struct rq *src_rq; u64 dmin = LONG_MAX; if (likely(!dl_overloaded(this_rq))) - return 0; + return; /* * Match the barrier from dl_set_overloaded; this guarantees that if we @@ -1535,7 +1535,7 @@ static int pull_dl_task(struct rq *this_rq) src_rq->curr->dl.deadline)) goto skip; - ret = 1; + resched = true; deactivate_task(src_rq, p, 0); set_task_cpu(p, this_cpu); @@ -1548,7 +1548,8 @@ static int pull_dl_task(struct rq *this_rq) double_unlock_balance(this_rq, src_rq); } - return ret; + if (resched) + resched_curr(this_rq); } /* @@ -1704,8 +1705,7 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p) if (!task_on_rq_queued(p) || rq->dl.dl_nr_running) return; - if (pull_dl_task(rq)) - resched_curr(rq); + pull_dl_task(rq); } /*