From: sashiko-bot@kernel.org
To: "Yury Norov" <ynorov@nvidia.com>
Cc: linux-s390@vger.kernel.org, "Heiko Carstens" <hca@linux.ibm.com>,
"Vasily Gorbik" <gor@linux.ibm.com>,
"Alexander Gordeev" <agordeev@linux.ibm.com>,
"Christian Borntraeger" <borntraeger@linux.ibm.com>
Subject: Re: [PATCH 3/6] sched: Restore preferred CPUs when hotplug removes the last one
Date: Sun, 01 Nov 2026 19:32:48 +0000 [thread overview]
Message-ID: <sashiko-outbox-192615@kernel.org> (raw)
In-Reply-To: <20261101192203.6979-4-ynorov@nvidia.com>
> Offlining the last preferred CPU leaves cpu_preferred_mask empty. Normal
> fair load balancing stops, potentially leaving CPUs idle while tasks
> remain queued.
>
> Currently, the steal governor is the only module that may modify the mask,
> so it takes care of this by resetting the mask to mirror the active
> cpumask, but stops sampling after that.
>
> This series adds more ways to control the preferred cpumask, so steal
> governor may not be active.
>
> Restore all remaining active CPUs as preferred in sched_cpu_deactivate()
> path, without relying on the steal governor to recover.
>
> Signed-off-by: Yury Norov <ynorov@nvidia.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261101192203.6979-1-ynorov@nvidia.com?part=3
next prev parent reply other threads:[~2026-11-01 19:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-01 19:21 [PATCH 0/6] sched: Expose writable interface for preferred CPUs mask Yury Norov
2026-11-01 19:21 ` [PATCH 1/6] sched: decouple PREFERRED_CPU from PARAVIRT in Kconfig.preempt Yury Norov
2026-11-01 19:28 ` sashiko-bot
2026-11-02 10:16 ` Ilya Leoshkevich
2026-11-02 11:00 ` Peter Zijlstra
2026-11-02 11:34 ` Ilya Leoshkevich
2026-11-02 13:00 ` Shrikanth Hegde
2026-11-02 13:41 ` Ilya Leoshkevich
2026-11-02 14:57 ` Shrikanth Hegde
2026-11-01 19:21 ` [PATCH 2/6] cpumask: Add reset_preferred_cpumask() helper Yury Norov
2026-11-01 19:28 ` sashiko-bot
2026-11-01 19:21 ` [PATCH 3/6] sched: Restore preferred CPUs when hotplug removes the last one Yury Norov
2026-11-01 19:32 ` sashiko-bot [this message]
2026-11-01 19:22 ` [PATCH 4/6] sched: serialize preferred cpumask update better Yury Norov
2026-11-01 19:32 ` sashiko-bot
2026-11-01 19:22 ` [PATCH 5/6] virt: steal_governor: Warn on unexpected preferred mask states Yury Norov
2026-11-01 19:36 ` sashiko-bot
2026-11-01 19:22 ` [PATCH 6/6] cpu: Add per-CPU preferred sysfs control Yury Norov
2026-11-01 19:40 ` sashiko-bot
2026-11-02 8:47 ` [PATCH 0/6] sched: Expose writable interface for preferred CPUs mask Peter Zijlstra
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