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: f95d4eaee6
("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>
This commit is contained in:

committed by
Ingo Molnar

parent
2eeb01a28c
commit
a0e813f26e
@@ -1716,7 +1716,7 @@ struct sched_class {
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struct task_struct *(*pick_next_task)(struct rq *rq);
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void (*put_prev_task)(struct rq *rq, struct task_struct *p);
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void (*set_next_task)(struct rq *rq, struct task_struct *p);
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void (*set_next_task)(struct rq *rq, struct task_struct *p, bool first);
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#ifdef CONFIG_SMP
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int (*balance)(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
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@@ -1768,7 +1768,7 @@ static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
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static inline void set_next_task(struct rq *rq, struct task_struct *next)
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{
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WARN_ON_ONCE(rq->curr != next);
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next->sched_class->set_next_task(rq, next);
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next->sched_class->set_next_task(rq, next, false);
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}
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#ifdef CONFIG_SMP
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