The 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")
Reviewed-by: Ben Segall <[email protected]>
Reviewed-by: Dave Chiluk <[email protected]>
Signed-off-by: Qian Cai <[email protected]>
---
Resend it since the offensive commit is now in the mainline.
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 d4bbf68c3161..b4fb016e3557 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)
@@ -4994,15 +4989,13 @@ 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
de53fd7aedb1 has just been merged into Linus' mainline tree for
eventual inclusion in 5.4. This should be pushed into there, and not
wait till 5.5.
Both I and Ben Segall have already +1'd this in previous threads.
Sorry for introducing the warnings.
Dave.
On Wed, Sep 18, 2019 at 2:02 PM Qian Cai <[email protected]> wrote:
>
> The 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")
> Reviewed-by: Ben Segall <[email protected]>
> Reviewed-by: Dave Chiluk <[email protected]>
> Signed-off-by: Qian Cai <[email protected]>
> ---
>
> Resend it since the offensive commit is now in the mainline.
>
> 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 d4bbf68c3161..b4fb016e3557 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)
> @@ -4994,15 +4989,13 @@ 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
>