From: Peter Zijlstra <peterz@infradead.org>
To: Tejun Heo <tj@kernel.org>
Cc: David Vernet <void@manifault.com>,
Andrea Righi <arighi@nvidia.com>,
Changwoo Min <changwoo@igalia.com>,
Dan Schatzberg <dschatzberg@meta.com>,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
sched-ext@lists.linux.dev
Subject: Re: [PATCH v2 4/4] sched_ext: Fix cgroup exit ordering by moving sched_ext_free() to finish_task_switch()
Date: Mon, 3 Nov 2025 21:38:05 +0100 [thread overview]
Message-ID: <20251103203805.GH3245006@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <aQkRKC15ta5Wo-lU@slm.duckdns.org>
On Mon, Nov 03, 2025 at 10:31:36AM -1000, Tejun Heo wrote:
> Hello,
>
> On Mon, Nov 03, 2025 at 09:28:43PM +0100, Peter Zijlstra wrote:
> > > @@ -5222,6 +5222,12 @@ static struct rq *finish_task_switch(str
> > > if (prev->sched_class->task_dead)
> > > prev->sched_class->task_dead(prev);
> >
> > ^^^ can you not use task_dead_scx() ?
>
> Unfortunately not. Because sched class switches are atomic infallible
> operations, all tasks in the system must be prepped on scheduler attach &
> fork regardless of their current sched class and thus have to be cleaned up
> in the same way on detach & exit.
Ah, I see scx_post_fork() and sched_ext_free^H^H^H^Hdead() effectively
duplicate the tasklist.
Oh well.
next prev parent reply other threads:[~2025-11-03 20:38 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 6:19 [PATCHSET cgroup/for-6.19] cgroup: Fix task exit ordering Tejun Heo
2025-10-29 6:19 ` [PATCH 1/4] cgroup: Rename cgroup lifecycle hooks to cgroup_task_*() Tejun Heo
2025-10-31 2:25 ` Chen Ridong
2025-10-29 6:19 ` [PATCH 2/4] cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free() Tejun Heo
2025-11-14 17:48 ` Michal Koutný
2025-11-14 18:18 ` Tejun Heo
2025-10-29 6:19 ` [PATCH 3/4] cgroup: Defer task cgroup unlink until after the task is done switching out Tejun Heo
2025-11-14 17:48 ` Michal Koutný
2025-10-29 6:19 ` [PATCH 4/4] sched_ext: Fix cgroup exit ordering by moving sched_ext_free() to finish_task_switch() Tejun Heo
2025-10-31 19:32 ` Andrea Righi
2025-11-03 20:25 ` [PATCH v2 " Tejun Heo
2025-11-03 20:28 ` Peter Zijlstra
2025-11-03 20:31 ` Tejun Heo
2025-11-03 20:38 ` Peter Zijlstra [this message]
2025-11-03 20:26 ` [PATCHSET cgroup/for-6.19] cgroup: Fix task exit ordering Tejun Heo
2025-11-03 22:04 ` [PATCH v2 0/4] " Tejun Heo
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