From: Tejun Heo <tj@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: David Vernet <void@manifault.com>,
Andrea Righi <arighi@nvidia.com>,
Changwoo Min <changwoo@igalia.com>,
sched-ext@lists.linux.dev, Emil Tsalapatis <emil@etsalapatis.com>,
ElXreno <elxreno@gmail.com>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 2/6] sched/core: Make core-sched flips wait for in-flight selections
Date: Mon, 10 Aug 2026 12:10:20 -1000 [thread overview]
Message-ID: <07a6cb06c1edc43bee7e8a2c20661a2c@kernel.org> (raw)
In-Reply-To: <20260810111546.GV687043@noisy.programming.kicks-ass.net>
Hello, Peter.
On Mon, Aug 10, 2026 at 01:15:46PM +0200, Peter Zijlstra wrote:
> I'm not entirely sure this is the right commit. I suspect this was a
> problem right from the beginning. This pick_next_task() always had a
> prev_balance() call that could drop the locks IIRC.
You're right. The balance calls could drop the shared lock mid-selection
since 539f65125d20 ("sched: Add core wide task selection and scheduling"),
so stable should target v5.14+. The sched_ext fold only made the window a
lot more frequent.
How would you like the two sched/core patches routed? I can take the whole
set through sched_ext/for-7.2-fixes, or hold the sched_ext side until the
first two come through tip.
Thanks.
--
tejun
next prev parent reply other threads:[~2026-08-10 22:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-07 21:02 [PATCHSET sched_ext/for-7.2-fixes] sched_ext: Fix core scheduling Tejun Heo
2026-08-07 21:02 ` [PATCH 1/6] sched/core: Handle pick_task() releasing the rq lock Tejun Heo
2026-08-07 21:26 ` sashiko-bot
2026-08-10 11:00 ` Peter Zijlstra
2026-08-07 21:02 ` [PATCH 2/6] sched/core: Make core-sched flips wait for in-flight selections Tejun Heo
2026-08-10 11:15 ` Peter Zijlstra
2026-08-10 22:10 ` Tejun Heo [this message]
2026-08-07 21:02 ` [PATCH 3/6] sched_ext: Replace SCX_RQ_BAL_KEEP with a dispatch verdict return Tejun Heo
2026-08-11 7:43 ` Andrea Righi
2026-08-07 21:02 ` [PATCH 4/6] sched_ext: Fix this_rq() assumptions in dispatch kfuncs Tejun Heo
2026-08-07 21:02 ` [PATCH 5/6] sched_ext: Count rq lock releases in rq->scx.lock_drop_seq Tejun Heo
2026-08-07 21:02 ` [PATCH 6/6] sched_ext: Fix rq->core_pick corruption under core scheduling Tejun Heo
2026-08-07 21:22 ` sashiko-bot
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