Commit 763a9ec0 authored Aug 20, 2019 by Qian Cai Committed by Ingo Molnar Sep 25, 2019

sched/fair: Fix -Wunused-but-set-variable warnings



Commit:

   de53fd7a ("sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices")

introduced a few compilation warnings:

  kernel/sched/fair.c: In function '__refill_cfs_bandwidth_runtime':
  kernel/sched/fair.c:4365:6: warning: variable 'now' set but not used [-Wunused-but-set-variable]
  kernel/sched/fair.c: In function 'start_cfs_bandwidth':
  kernel/sched/fair.c:4992:6: warning: variable 'overrun' set but not used [-Wunused-but-set-variable]

Also, __refill_cfs_bandwidth_runtime() does no longer update the
expiration time, so fix the comments accordingly.

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Reviewed-by: Dave Chiluk <chiluk+linux@indeed.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: pauld@redhat.com
Fixes: de53fd7a ("sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices")
Link: https://lkml.kernel.org/r/1566326455-8038-1-git-send-email-cai@lca.pw


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 714e501e

kernel/sched/fair.c

+6 −13

Original line number	Diff line number	Diff line
		@@ -4353,20 +4353,15 @@ static inline u64 sched_cfs_bandwidth_slice(void)
		}

		/*
		* Replenish runtime according to assigned quota and update expiration time.
		* We use sched_clock_cpu directly instead of rq->clock to avoid adding
		* additional synchronization around rq->lock.
		* Replenish runtime according to assigned quota. We use sched_clock_cpu
		* directly instead of rq->clock to avoid adding additional synchronization
		* around rq->lock.
		*
		* requires cfs_b->lock
		*/
		void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
		{
		u64 now;

		if (cfs_b->quota == RUNTIME_INF)
		return;

		now = sched_clock_cpu(smp_processor_id());
		if (cfs_b->quota != RUNTIME_INF)
		cfs_b->runtime = cfs_b->quota;
		}

		@@ -4983,15 +4978,13 @@ static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)

		void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
		{
		u64 overrun;

		lockdep_assert_held(&cfs_b->lock);

		if (cfs_b->period_active)
		return;

		cfs_b->period_active = 1;
		overrun = hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
		hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
		hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED);
		}

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