Re: [PATCH] sched/fair: Fix inaccurate h_nr_runnable accounting with delayed dequeue

[Madadi Vineeth Reddy]

Hi Prateek,

>A SCHED_WARN_ON() to inspect h_nr_runnable post its update in
>dequeue_entities() like below:
>
>    cfs_rq->h_nr_runnable -= h_nr_runnable;
>    SCHED_WARN_ON(((int) cfs_rq->h_nr_runnable) < 0);
>
>is consistently tripped when running wakeup intensive workloads like
>hackbench in a cgroup.

I observed that the WARN_ON is triggered during the boot process without
the patch, and the patch resolves the issue.

However, I was unable to trigger the WARN_ON by running hackbench in a
cgroup without the patch. Could you please share the specific test
scenario or configuration you used to reproduce it?

For the boot process scenario:
Tested-by: Madadi Vineeth Reddy <vineethr@xxxxxxxxxxxxx>

Thanks,
Madadi Vineeth Reddy