lkml.org 
[lkml]   [2019]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH -next v2] sched/fair: fix -Wunused-but-set-variable warnings
From
Date
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 <cai@lca.pw>
>
> 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 <cai@lca.pw>
> 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 <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: mingo@redhat.com
> Cc: pauld@redhat.com
> Link: https://lkml.kernel.org/r/1566326455-8038-1-git-send-email-cai@lca.pw
> ---
> 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);
> }
>

\
 
 \ /
  Last update: 2019-09-10 22:58    [W:0.064 / U:0.460 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site