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| author | Peter Zijlstra <peterz@infradead.org> | 2019-11-08 16:16:00 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-11-11 10:35:21 +0300 |
| commit | a0e813f26ebcb25c0b5e504498fbd796cca1a4ba (patch) | |
| tree | c6a926cff783866cc5ee1b20ffefb559e78d45fa /kernel/sched/rt.c | |
| parent | 2eeb01a28c9233333bf229a5b4b0559f4bd22b52 (diff) | |
| download | linux-a0e813f26ebcb25c0b5e504498fbd796cca1a4ba.tar.xz | |
sched/core: Further clarify sched_class::set_next_task()
It turns out there really is something special to the first
set_next_task() invocation. In specific the 'change' pattern really
should not cause balance callbacks.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: juri.lelli@redhat.com
Cc: ktkhai@virtuozzo.com
Cc: mgorman@suse.de
Cc: qais.yousef@arm.com
Cc: qperret@google.com
Cc: rostedt@goodmis.org
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Fixes: f95d4eaee6d0 ("sched/{rt,deadline}: Fix set_next_task vs pick_next_task")
Link: https://lkml.kernel.org/r/20191108131909.775434698@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/rt.c')
| -rw-r--r-- | kernel/sched/rt.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 38027c04b04c..e591d40fd645 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1515,13 +1515,16 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flag #endif } -static inline void set_next_task_rt(struct rq *rq, struct task_struct *p) +static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool first) { p->se.exec_start = rq_clock_task(rq); /* The running task is never eligible for pushing */ dequeue_pushable_task(rq, p); + if (!first) + return; + /* * If prev task was rt, put_prev_task() has already updated the * utilization. We only care of the case where we start to schedule a @@ -1572,7 +1575,7 @@ static struct task_struct *pick_next_task_rt(struct rq *rq) return NULL; p = _pick_next_task_rt(rq); - set_next_task_rt(rq, p); + set_next_task_rt(rq, p, true); return p; } |