From: Thomas Gleixner <tglx@kernel.org>
To: Jing Wu <realwujing@gmail.com>, 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>,
"Paul E. McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
Joel Fernandes <joelagnelf@nvidia.com>,
Josh Triplett <josh@joshtriplett.org>,
Boqun Feng <boqun@kernel.org>,
Uladzislau Rezki <urezki@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang@linux.dev>,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Tejun Heo <tj@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
Shuah Khan <shuah@kernel.org>
Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kselftest@vger.kernel.org, Jing Wu <realwujing@gmail.com>,
Qiliang Yuan <yuanql9@chinatelecom.cn>
Subject: Re: [PATCH v3 05/13] cpu/hotplug: Reserve CPUHP states for nohz_full and managed IRQ down-paths
Date: Thu, 18 Jun 2026 23:01:27 +0200 [thread overview]
Message-ID: <874iizef6g.ffs@fw13> (raw)
In-Reply-To: <871pe3de9b.ffs@fw13>
On Thu, Jun 18 2026 at 18:06, Thomas Gleixner wrote:
> On Thu, Jun 18 2026 at 11:11, Jing Wu wrote:
>> Add CPUHP_AP_NO_HZ_FULL_DYING and CPUHP_AP_IRQ_AFFINITY_DYING to the
>> cpuhp_state enum. These dying callbacks are invoked during CPU offline
>> before the tick is stopped, enabling clean tick handover and managed
>> IRQ migration when a CPU transitions between isolated and housekeeping
>> states.
>>
>> The existing CPUHP_AP_IRQ_AFFINITY_ONLINE already handles managed IRQ
>> restoration on CPU online. The new dying callback completes the pair,
>> migrating managed interrupts away from the CPU before it goes down.
>
> What? They are migrated away today already when the CPU goes down unless
> the CPU is the last one in the affinity set of the interrupt. So why do
> you need a new step for something which already exists?
Aside of that these hotplug states are not used at all. So what is this
patch for?
next prev parent reply other threads:[~2026-06-18 21:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-18 3:11 [PATCH v3 00/13] Dynamic Housekeeping Management (DHM) via CPUSets Jing Wu
2026-06-18 3:11 ` [PATCH v3 01/13] sched/isolation: Replace notifier chain with explicit callback interface Jing Wu
2026-06-18 3:11 ` [PATCH v3 02/13] sched/isolation: Add housekeeping_update_types() for kernel-noise masks Jing Wu
2026-06-18 3:11 ` [PATCH v3 03/13] sched/isolation: RCU-protect all housekeeping cpumask readers Jing Wu
2026-06-18 3:11 ` [PATCH v3 04/13] sched/isolation: Fix RCU protection for runtime-mutable cpumask callers Jing Wu
2026-06-18 3:11 ` [PATCH v3 05/13] cpu/hotplug: Reserve CPUHP states for nohz_full and managed IRQ down-paths Jing Wu
2026-06-18 16:06 ` Thomas Gleixner
2026-06-18 21:01 ` Thomas Gleixner [this message]
2026-06-18 3:11 ` [PATCH v3 06/13] tick/nohz, context_tracking: Prepare for runtime nohz_full updates Jing Wu
2026-06-18 17:27 ` Thomas Gleixner
2026-06-18 19:49 ` Thomas Gleixner
2026-06-18 3:11 ` [PATCH v3 07/13] rcu/nocb: Add explicit housekeeping callback for runtime NOCB toggling Jing Wu
2026-06-18 3:11 ` [PATCH v3 08/13] genirq: Add explicit housekeeping callback for managed IRQ migration Jing Wu
2026-06-18 20:27 ` Thomas Gleixner
2026-06-18 21:11 ` Thomas Gleixner
2026-06-18 3:11 ` [PATCH v3 09/13] watchdog/lockup_detector: Register housekeeping callback for kernel-noise Jing Wu
2026-06-18 3:11 ` [PATCH v3 10/13] sched: Guard sched_tick_start/stop against uninitialized tick_work_cpu Jing Wu
2026-06-18 20:50 ` Thomas Gleixner
2026-06-18 3:11 ` [PATCH v3 11/13] cgroup/cpuset: Extend isolated partition to trigger kernel-noise isolation Jing Wu
2026-06-18 20:55 ` Thomas Gleixner
2026-06-18 3:11 ` [PATCH v3 12/13] docs: cgroup-v2: Document kernel-noise isolation via isolated partitions Jing Wu
2026-06-18 3:11 ` [PATCH v3 13/13] selftests/cgroup: Add kernel-noise isolation test to cpuset selftest Jing Wu
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