Re: [RFC][PATCH 08/10] sched/fair: Implement delayed dequeue

Mike Galbraith
2024-04-16T05:37:18Z

On Tue, 2024-04-16 at 08:48 +0530, K Prateek Nayak wrote:
>
> Wondering if you are running into the issue where pick_eevdf() returns
> NULL despite there being runnable CFS task on the runqueue. Can you try
> running with the following patch from Chenyu -
> https://lore.kernel.org/lkml/20240226082349.302363-1-yu.c.chen@intel.com/

I hadn't tried it in master branch, but had in my 6.1-eevdf tree which
contains the previous delay dequeue version, because I found that it
too would explode, which surprised me having run it quite a bit woe
free. Patch helped 6.1-eevdf not at all. I just tried it in master to
be sure, and while the death throes were not identical, this one began
with SCHED_WARN_ON() in put_prev_entity(), box still went belly up.

BTW/FWIW, turning on AUTOGROUP seemingly rendered box immune (unless
booted with noautogroup 'course), and that immunity even held when I
launched all players in the same cgroup (hmm).

-Mike