Messages in this thread | | | From | Vincent Guittot <> | Date | Fri, 2 Jul 2021 10:08:09 +0200 | Subject | Re: [PATCH] sched/fair: Sync load_sum with load_avg after dequeue |
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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 > > >
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