sched/fair: Advance global expiration when period timer is restarted
When period gets restarted after some idle time, start_cfs_bandwidth() doesn't update the expiration information, expire_cfs_rq_runtime() will see cfs_rq->runtime_expires smaller than rq clock and go to the clock drift logic, wasting needless CPU cycles on the scheduler hot path. Update the global expiration in start_cfs_bandwidth() to avoid frequent expire_cfs_rq_runtime() calls once a new period begins. Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180620101834.24455-2-xlpang@linux.alibaba.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -5204,13 +5204,18 @@ static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
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void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
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{
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u64 overrun;
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lockdep_assert_held(&cfs_b->lock);
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if (!cfs_b->period_active) {
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if (cfs_b->period_active)
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return;
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cfs_b->period_active = 1;
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hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
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overrun = hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
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cfs_b->runtime_expires += (overrun + 1) * ktime_to_ns(cfs_b->period);
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cfs_b->expires_seq++;
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hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED);
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}
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}
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static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
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