From: K Prateek Nayak <kprateek.nayak@amd.com>
To: Andrea Righi <arighi@nvidia.com>, Tejun Heo <tj@kernel.org>,
David Vernet <void@manifault.com>,
Changwoo Min <changwoo@igalia.com>,
John Stultz <jstultz@google.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, "Mel Gorman" <mgorman@suse.de>,
Valentin Schneider <vschneid@redhat.com>,
"Christian Loehle" <christian.loehle@arm.com>,
David Dai <david.dai@linux.dev>, Koba Ko <kobak@nvidia.com>,
Aiqun Yu <aiqun.yu@oss.qualcomm.com>,
Shuah Khan <shuah@kernel.org>, <sched-ext@lists.linux.dev>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/9] sched/core: Drop mutex locks before proxy rescheduling
Date: Mon, 6 Jul 2026 14:15:50 +0530 [thread overview]
Message-ID: <22d12b79-6a5d-488c-856f-1a4ab528786f@amd.com> (raw)
In-Reply-To: <20260706070410.282826-2-arighi@nvidia.com>
Hello Andrea,
On 7/6/2026 12:20 PM, Andrea Righi wrote:
> find_proxy_task() can call proxy_resched_idle() while holding a mutex
> wait_lock and the blocked task lock. Guard cleanup does not run until
> after the return expression is evaluated.
>
> proxy_resched_idle() invokes scheduling-class callbacks through
> put_prev_set_next_task(). Calling those callbacks with the mutex locks
> held prevents them from safely inspecting the proxy chain, as doing so
> may require acquiring the same locks.
>
> This is a preparatory change to support proxy execution in sched_ext. It
> leaves the guard scope before calling proxy_resched_idle() so sched_ext
> callbacks can safely inspect the proxy chain.
>
> Signed-off-by: Andrea Righi <arighi@nvidia.com>
I don't see the need to hold anything more than the rq_lock for
proxy_resched_idle(). Feel free to include:
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
--
Thanks and Regards,
Prateek
next prev parent reply other threads:[~2026-07-06 8:46 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-06 6:50 [PATCHSET v3 sched_ext/for-7.3] sched: Make proxy execution compatible with sched_ext Andrea Righi
2026-07-06 6:50 ` [PATCH 1/9] sched/core: Drop mutex locks before proxy rescheduling Andrea Righi
2026-07-06 8:45 ` K Prateek Nayak [this message]
2026-07-06 6:50 ` [PATCH 2/9] sched_ext: Split curr|donor references properly Andrea Righi
2026-07-06 6:50 ` [PATCH 3/9] sched_ext: Fix TOCTOU race in consume_remote_task() Andrea Righi
2026-07-06 6:50 ` [PATCH 4/9] sched_ext: Handle blocked donor migration with proxy execution Andrea Righi
2026-07-06 6:51 ` [PATCH 5/9] sched_ext: Fix ops.running/stopping() pairing for proxy-exec donors Andrea Righi
2026-07-06 6:51 ` [PATCH 6/9] sched_ext: Delegate proxy donor admission to BPF schedulers Andrea Righi
2026-07-06 7:49 ` K Prateek Nayak
2026-07-06 6:51 ` [PATCH 7/9] sched_ext: Add selftest for blocked donor admission Andrea Righi
2026-07-06 6:51 ` [PATCH 8/9] sched_ext: scx_qmap: Add proxy execution support Andrea Righi
2026-07-06 6:51 ` [PATCH 9/9] sched: Allow enabling proxy exec with sched_ext Andrea Righi
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