* [PATCH] sched/fair: Sync load_sum with load_avg after dequeue
@ 2021-07-01 17:18 Vincent Guittot
2021-07-02 6:15 ` Sachin Sant
2021-07-05 7:53 ` [tip: sched/urgent] " tip-bot2 for Vincent Guittot
0 siblings, 2 replies; 5+ messages in thread
From: Vincent Guittot @ 2021-07-01 17:18 UTC (permalink / raw)
To: mingo, peterz, juri.lelli, dietmar.eggemann, rostedt, bsegall,
mgorman, bristot, linux-kernel, odin, sachinp
Cc: Vincent Guittot
commit 9e077b52d86a ("sched/pelt: Check that *_avg are null when *_sum are")
reported some inconsitencies between *_avg and *_sum.
commit 1c35b07e6d39 ("sched/fair: Ensure _sum and _avg values stay consistent")
fixed some but one remains when dequeuing load.
sync the cfs's load_sum with its load_avg after dequeuing the load of a
sched_entity.
Fixes: 9e077b52d86a ("sched/pelt: Check that *_avg are null when *_sum are")
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
I have been able to trigger a WARN on my system even with the patch
listed above. This patch fixes it.
Sachin could you test that it also fixes yours ?
kernel/sched/fair.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 11d22943753f..48fc7dfc2f66 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3037,8 +3037,9 @@ enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
static inline void
dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
+ u32 divider = get_pelt_divider(&se->avg);
sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
- sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum);
+ cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * divider;
}
#else
static inline void
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] sched/fair: Sync load_sum with load_avg after dequeue
2021-07-01 17:18 [PATCH] sched/fair: Sync load_sum with load_avg after dequeue Vincent Guittot
@ 2021-07-02 6:15 ` Sachin Sant
2021-07-02 8:08 ` Vincent Guittot
2021-07-05 7:53 ` [tip: sched/urgent] " tip-bot2 for Vincent Guittot
1 sibling, 1 reply; 5+ messages in thread
From: Sachin Sant @ 2021-07-02 6:15 UTC (permalink / raw)
To: Vincent Guittot
Cc: Ingo Molnar, Peter Zijlstra, Juri Lelli, Dietmar Eggemann,
rostedt, bsegall, mgorman, bristot, linux-kernel, odin
> On 01-Jul-2021, at 10:48 PM, Vincent Guittot <vincent.guittot@linaro.org> wrote:
>
> commit 9e077b52d86a ("sched/pelt: Check that *_avg are null when *_sum are")
> reported some inconsitencies between *_avg and *_sum.
>
> commit 1c35b07e6d39 ("sched/fair: Ensure _sum and _avg values stay consistent")
> fixed some but one remains when dequeuing load.
>
> sync the cfs's load_sum with its load_avg after dequeuing the load of a
> sched_entity.
>
> Fixes: 9e077b52d86a ("sched/pelt: Check that *_avg are null when *_sum are")
> Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
>
> I have been able to trigger a WARN on my system even with the patch
> listed above. This patch fixes it.
> Sachin could you test that it also fixes yours ?
>
I ran various LTP stress tests, scheduler tests and kernel compile operation for about 5 hours.
Haven’t seen the warning during the testing.
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
I have left the tests running, will let it run for few more hours.
Thanks
-Sachin
> kernel/sched/fair.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 11d22943753f..48fc7dfc2f66 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3037,8 +3037,9 @@ enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
> static inline void
> dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
> {
> + u32 divider = get_pelt_divider(&se->avg);
> sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
> - sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum);
> + cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * divider;
> }
> #else
> static inline void
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] sched/fair: Sync load_sum with load_avg after dequeue
2021-07-02 6:15 ` Sachin Sant
@ 2021-07-02 8:08 ` Vincent Guittot
2021-07-02 9:02 ` Odin Ugedal
0 siblings, 1 reply; 5+ messages in thread
From: Vincent Guittot @ 2021-07-02 8:08 UTC (permalink / raw)
To: Sachin Sant
Cc: Ingo Molnar, Peter Zijlstra, Juri Lelli, Dietmar Eggemann,
Steven Rostedt, Ben Segall, Mel Gorman,
Daniel Bristot de Oliveira, linux-kernel, Odin Ugedal
On Fri, 2 Jul 2021 at 08:16, Sachin Sant <sachinp@linux.vnet.ibm.com> wrote:
>
>
>
> > On 01-Jul-2021, at 10:48 PM, Vincent Guittot <vincent.guittot@linaro.org> wrote:
> >
> > commit 9e077b52d86a ("sched/pelt: Check that *_avg are null when *_sum are")
> > reported some inconsitencies between *_avg and *_sum.
> >
> > commit 1c35b07e6d39 ("sched/fair: Ensure _sum and _avg values stay consistent")
> > fixed some but one remains when dequeuing load.
> >
> > sync the cfs's load_sum with its load_avg after dequeuing the load of a
> > sched_entity.
> >
> > Fixes: 9e077b52d86a ("sched/pelt: Check that *_avg are null when *_sum are")
> > Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
> > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> > ---
> >
> > I have been able to trigger a WARN on my system even with the patch
> > listed above. This patch fixes it.
> > Sachin could you test that it also fixes yours ?
> >
>
> I ran various LTP stress tests, scheduler tests and kernel compile operation for about 5 hours.
> Haven’t seen the warning during the testing.
>
> Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Thanks
>
> I have left the tests running, will let it run for few more hours.
>
> Thanks
> -Sachin
>
> > kernel/sched/fair.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index 11d22943753f..48fc7dfc2f66 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -3037,8 +3037,9 @@ enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
> > static inline void
> > dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
> > {
> > + u32 divider = get_pelt_divider(&se->avg);
> > sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
> > - sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum);
> > + cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * divider;
> > }
> > #else
> > static inline void
> > --
> > 2.17.1
> >
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] sched/fair: Sync load_sum with load_avg after dequeue
2021-07-02 8:08 ` Vincent Guittot
@ 2021-07-02 9:02 ` Odin Ugedal
0 siblings, 0 replies; 5+ messages in thread
From: Odin Ugedal @ 2021-07-02 9:02 UTC (permalink / raw)
To: Vincent Guittot
Cc: Sachin Sant, Ingo Molnar, Peter Zijlstra, Juri Lelli,
Dietmar Eggemann, Steven Rostedt, Ben Segall, Mel Gorman,
Daniel Bristot de Oliveira, linux-kernel, Odin Ugedal
Thanks,
Reviewed-by: Odin Ugedal <odin@uged.al>
Odin
^ permalink raw reply [flat|nested] 5+ messages in thread
* [tip: sched/urgent] sched/fair: Sync load_sum with load_avg after dequeue
2021-07-01 17:18 [PATCH] sched/fair: Sync load_sum with load_avg after dequeue Vincent Guittot
2021-07-02 6:15 ` Sachin Sant
@ 2021-07-05 7:53 ` tip-bot2 for Vincent Guittot
1 sibling, 0 replies; 5+ messages in thread
From: tip-bot2 for Vincent Guittot @ 2021-07-05 7:53 UTC (permalink / raw)
To: linux-tip-commits
Cc: Sachin Sant, Vincent Guittot, Peter Zijlstra (Intel),
Odin Ugedal, x86, linux-kernel
The following commit has been merged into the sched/urgent branch of tip:
Commit-ID: ceb6ba45dc8074d2a1ec1117463dc94a20d4203d
Gitweb: https://git.kernel.org/tip/ceb6ba45dc8074d2a1ec1117463dc94a20d4203d
Author: Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Thu, 01 Jul 2021 19:18:37 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 02 Jul 2021 15:58:23 +02:00
sched/fair: Sync load_sum with load_avg after dequeue
commit 9e077b52d86a ("sched/pelt: Check that *_avg are null when *_sum are")
reported some inconsitencies between *_avg and *_sum.
commit 1c35b07e6d39 ("sched/fair: Ensure _sum and _avg values stay consistent")
fixed some but one remains when dequeuing load.
sync the cfs's load_sum with its load_avg after dequeuing the load of a
sched_entity.
Fixes: 9e077b52d86a ("sched/pelt: Check that *_avg are null when *_sum are")
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Odin Ugedal <odin@uged.al>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20210701171837.32156-1-vincent.guittot@linaro.org
---
kernel/sched/fair.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 45edf61..1e263c9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3037,8 +3037,9 @@ enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
static inline void
dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
+ u32 divider = get_pelt_divider(&se->avg);
sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
- sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum);
+ cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * divider;
}
#else
static inline void
^ permalink raw reply related [flat|nested] 5+ messages in thread
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2021-07-01 17:18 [PATCH] sched/fair: Sync load_sum with load_avg after dequeue Vincent Guittot
2021-07-02 6:15 ` Sachin Sant
2021-07-02 8:08 ` Vincent Guittot
2021-07-02 9:02 ` Odin Ugedal
2021-07-05 7:53 ` [tip: sched/urgent] " tip-bot2 for Vincent Guittot
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