From: Tejun Heo <tj@kernel.org>
To: Doug Anderson <dianders@chromium.org>
Cc: David Vernet <void@manifault.com>,
linux-kernel@vger.kernel.org, kernel-team@meta.com,
sched-ext@meta.com, Andrea Righi <arighi@nvidia.com>,
Changwoo Min <multics69@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH sched_ext/for-6.13 2/2] sched_ext: Enable the ops breather and eject BPF scheduler on softlockup
Date: Wed, 6 Nov 2024 13:07:51 -1000 [thread overview]
Message-ID: <Zyv2x6kb3gO8cTO7@slm.duckdns.org> (raw)
In-Reply-To: <CAD=FV=UTh=JGUDZxO74+ZRQbF+yzcWnBo-f=oie0msmBn2_00g@mail.gmail.com>
Hello,
On Wed, Nov 06, 2024 at 03:02:35PM -0800, Doug Anderson wrote:
...
> Honestly, it would feel better to me if the soft lockup timer didn't
> tell schedext to kill things but instead we just make some special
> exception for "schedext" tasks and exclude them from the softlockup
> detector because they're already being watched by their own watchdog.
> Would that be possible? Then tweaking the "softlockup" timeouts
> doesn't implicitly change how long schedext things can run.
Some systems can get into full blown live-lock condition where CPUs are
barely making forward progress through the scheduler and all normal (!RT &&
!DEADLINE) tasks are on sched_ext, so the only reasonable way to exclude
sched_ext would be disabling softlockup detection while sched_ext is
enabled which doesn't feel like a sound trade-off.
Thanks.
--
tejun
next prev parent reply other threads:[~2024-11-06 23:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-05 21:48 [PATCH sched_ext/for-6.13 1/2] sched_ext: Avoid live-locking bypass mode switching Tejun Heo
2024-11-05 21:49 ` [PATCH sched_ext/for-6.13 2/2] sched_ext: Enable the ops breather and eject BPF scheduler on softlockup Tejun Heo
2024-11-06 21:32 ` Doug Anderson
2024-11-06 22:08 ` Tejun Heo
2024-11-06 23:02 ` Doug Anderson
2024-11-06 23:07 ` Tejun Heo [this message]
2024-11-06 23:20 ` Doug Anderson
2024-11-07 19:31 ` Tejun Heo
2024-11-08 20:38 ` Tejun Heo
2024-11-05 22:03 ` [PATCH sched_ext/for-6.13 1/2] sched_ext: Avoid live-locking bypass mode switching David Vernet
2024-11-05 23:02 ` Tejun Heo
2024-11-05 23:57 ` Andrea Righi
2024-11-06 0:26 ` Tejun Heo
2024-11-06 0:33 ` Andrea Righi
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