On Tue, 2019-09-03 at 16:15 +0200, Peter Zijlstra wrote: > On Tue, Sep 03, 2019 at 09:03:26AM -0400, Qian Cai wrote: > > Ingo or Peter, please take a look at this trivial patch. Still see the > > warning > > in linux-next every day. > > > > On Tue, 2019-08-20 at 14:40 -0400, Qian Cai wrote: > > > 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+linux > > > @indeed.com/ > > > > > > Signed-off-by: Qian Cai <[email protected]> > > Rewrote the Changelog like so:
Looks good. I suppose it still need Ingo to pick it up, as today's tip/auto- latest still show those warnings. > > --- > Subject: sched/fair: Fix -Wunused-but-set-variable warnings > From: Qian Cai <[email protected]> > Date: Tue, 20 Aug 2019 14:40:55 -0400 > > Commit de53fd7aedb1 ("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. > > Fixes: de53fd7aedb1 ("sched/fair: Fix low cpu usage with high throttling by > removing expiration of cpu-local slices") > Signed-off-by: Qian Cai <[email protected]> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]> > Reviewed-by: Ben Segall <[email protected]> > Reviewed-by: Dave Chiluk <[email protected]> > Cc: [email protected] > Cc: [email protected] > Link: https://lkml.kernel.org/r/[email protected] > --- > kernel/sched/fair.c | 19 ++++++------------- > 1 file changed, 6 insertions(+), 13 deletions(-) > > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4386,21 +4386,16 @@ static inline u64 sched_cfs_bandwidth_sl > } > > /* > - * 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) > @@ -5021,15 +5016,13 @@ static void init_cfs_rq_runtime(struct c > > 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); > } >
