The linux-next commit "sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices" [1] 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. [1] https://lore.kernel.org/lkml/1558121424-2914-1-git-send-email-chiluk+li...@indeed.com/ Signed-off-by: Qian Cai <c...@lca.pw> --- v2: Keep hrtimer_forward_now() in start_cfs_bandwidth() per Ben. kernel/sched/fair.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 84959d3285d1..06782491691f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4354,21 +4354,16 @@ 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()); - cfs_b->runtime = cfs_b->quota; + if (cfs_b->quota != RUNTIME_INF) + cfs_b->runtime = cfs_b->quota; } static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) @@ -4989,15 +4984,13 @@ 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); } -- 1.8.3.1
