From: Thomas Gleixner <tglx@kernel•org>
To: "Waiman Long" <longman@redhat•com>, "Tejun Heo" <tj@kernel•org>,
"Johannes Weiner" <hannes@cmpxchg•org>,
"Michal Koutný" <mkoutny@suse•com>,
"Jonathan Corbet" <corbet@lwn•net>,
"Shuah Khan" <skhan@linuxfoundation•org>,
"Catalin Marinas" <catalin.marinas@arm•com>,
"Will Deacon" <will@kernel•org>,
"K. Y. Srinivasan" <kys@microsoft•com>,
"Haiyang Zhang" <haiyangz@microsoft•com>,
"Wei Liu" <wei.liu@kernel•org>,
"Dexuan Cui" <decui@microsoft•com>,
"Long Li" <longli@microsoft•com>,
"Guenter Roeck" <linux@roeck-us•net>,
"Frederic Weisbecker" <frederic@kernel•org>,
"Paul E. McKenney" <paulmck@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>,
"Steven Rostedt" <rostedt@goodmis•org>,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios•com>,
"Lai Jiangshan" <jiangshanlai@gmail•com>,
Zqiang <qiang.zhang@linux•dev>,
"Anna-Maria Behnsen" <anna-maria@linutronix•de>,
"Ingo Molnar" <mingo@kernel•org>,
"Chen Ridong" <chenridong@huaweicloud•com>,
"Peter Zijlstra" <peterz@infradead•org>,
"Juri Lelli" <juri.lelli@redhat•com>,
"Vincent Guittot" <vincent.guittot@linaro•org>,
"Dietmar Eggemann" <dietmar.eggemann@arm•com>,
"Ben Segall" <bsegall@google•com>, "Mel Gorman" <mgorman@suse•de>,
"Valentin Schneider" <vschneid@redhat•com>,
"K Prateek Nayak" <kprateek.nayak@amd•com>,
"David S. Miller" <davem@davemloft•net>,
"Eric Dumazet" <edumazet@google•com>,
"Jakub Kicinski" <kuba@kernel•org>,
"Paolo Abeni" <pabeni@redhat•com>,
"Simon Horman" <horms@kernel•org>
Cc: cgroups@vger•kernel.org, linux-doc@vger•kernel.org,
linux-kernel@vger•kernel.org,
linux-arm-kernel@lists•infradead.org,
linux-hyperv@vger•kernel.org, linux-hwmon@vger•kernel.org,
rcu@vger•kernel.org, netdev@vger•kernel.org,
linux-kselftest@vger•kernel.org,
Costa Shulyupin <cshulyup@redhat•com>,
Qiliang Yuan <realwujing@gmail•com>,
Waiman Long <longman@redhat•com>
Subject: Re: [PATCH 16/23] genirq/cpuhotplug: Use RCU to protect access of HK_TYPE_MANAGED_IRQ cpumask
Date: Tue, 21 Apr 2026 11:02:29 +0200 [thread overview]
Message-ID: <87qzo8bs9m.ffs@tglx> (raw)
In-Reply-To: <20260421030351.281436-17-longman@redhat.com>
On Mon, Apr 20 2026 at 23:03, Waiman Long wrote:
> As HK_TYPE_MANAGED_IRQ cpumask is going to be changeable at run time,
> use RCU to protect access to the cpumask.
>
> To enable the new HK_TYPE_MANAGED_IRQ cpumask to take effect, the
> following steps can be done.
Can be done?
> 1) Update the HK_TYPE_MANAGED_IRQ cpumask to take out the newly isolated
> CPUs and add back the de-isolated CPUs.
> 2) Tear down the affected CPUs to cause irq_migrate_all_off_this_cpu()
> to be called on the affected CPUs to migrate the irqs to other
> HK_TYPE_MANAGED_IRQ housekeeping CPUs.
> 3) Bring up the previously offline CPUs to invoke
> irq_affinity_online_cpu() to allow the newly de-isolated CPUs to
> be used for managed irqs.
Which previously offline CPUs?
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 2e8072437826..8270c4de260b 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -263,6 +263,7 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, bool
> housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) {
> const struct cpumask *hk_mask;
>
> + guard(rcu)();
> hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
>
> cpumask_and(tmp_mask, mask, hk_mask);
How is this hunk related to $Subject?
Thanks,
tglx
next prev parent reply other threads:[~2026-04-21 9:02 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-21 3:03 [PATCH-next 00/23] cgroup/cpuset: Enable runtime update of nohz_full and managed_irq CPUs Waiman Long
2026-04-21 3:03 ` [PATCH 01/23] sched/isolation: Add HK_TYPE_KERNEL_NOISE_BOOT & HK_TYPE_MANAGED_IRQ_BOOT Waiman Long
2026-04-21 3:03 ` [PATCH 02/23] sched/isolation: Enhance housekeeping_update() to support updating more than one HK cpumask Waiman Long
2026-04-22 6:39 ` Chen Ridong
2026-04-21 3:03 ` [PATCH 03/23] tick/nohz: Make nohz_full parameter optional Waiman Long
2026-04-21 8:32 ` Thomas Gleixner
2026-04-21 14:14 ` Waiman Long
2026-04-24 15:57 ` Frederic Weisbecker
2026-04-21 3:03 ` [PATCH 04/23] tick/nohz: Allow runtime changes in full dynticks CPUs Waiman Long
2026-04-21 8:50 ` Thomas Gleixner
2026-04-21 14:24 ` Waiman Long
2026-05-13 13:04 ` Frederic Weisbecker
2026-04-21 3:03 ` [PATCH 05/23] tick: Pass timer tick job to an online HK CPU in tick_cpu_dying() Waiman Long
2026-04-21 8:55 ` Thomas Gleixner
2026-04-21 14:22 ` Waiman Long
2026-04-21 3:03 ` [PATCH 06/23] rcu/nocbs: Allow runtime changes in RCU NOCBS cpumask Waiman Long
2026-04-21 3:03 ` [PATCH 07/23] watchdog: Sync up with runtime change of isolated CPUs Waiman Long
2026-04-21 3:03 ` [PATCH 08/23] arm64: topology: Use RCU to protect access to HK_TYPE_TICK cpumask Waiman Long
2026-04-22 9:34 ` Chen Ridong
2026-05-13 16:19 ` Frederic Weisbecker
2026-04-21 3:03 ` [PATCH 09/23] workqueue: Use RCU to protect access of HK_TYPE_TIMER cpumask Waiman Long
2026-04-21 3:03 ` [PATCH 10/23] cpu: " Waiman Long
2026-04-21 8:57 ` Thomas Gleixner
2026-04-21 14:25 ` Waiman Long
2026-04-21 3:03 ` [PATCH 11/23] hrtimer: " Waiman Long
2026-04-21 8:59 ` Thomas Gleixner
2026-04-21 3:03 ` [PATCH 12/23] net: Use boot time housekeeping cpumask settings for now Waiman Long
2026-04-21 3:03 ` [PATCH 13/23] sched/core: Use RCU to protect access of HK_TYPE_KERNEL_NOISE cpumask Waiman Long
2026-04-21 3:03 ` [PATCH 14/23] hwmon/coretemp: Use RCU to protect access of HK_TYPE_MISC cpumask Waiman Long
2026-04-21 3:03 ` [PATCH 15/23] Drivers: hv: Use RCU to protect access of HK_TYPE_MANAGED_IRQ cpumask Waiman Long
2026-04-21 3:03 ` [PATCH 16/23] genirq/cpuhotplug: " Waiman Long
2026-04-21 9:02 ` Thomas Gleixner [this message]
2026-04-21 14:29 ` Waiman Long
2026-04-21 3:03 ` [PATCH 17/23] sched/isolation: Extend housekeeping_dereference_check() to cover changes in nohz_full or manged_irqs cpumasks Waiman Long
2026-04-21 3:03 ` [PATCH 18/23] cpu/hotplug: Add a new cpuhp_offline_cb() API Waiman Long
2026-04-21 16:17 ` Thomas Gleixner
2026-04-21 17:29 ` Waiman Long
2026-04-21 18:43 ` Thomas Gleixner
2026-04-21 3:03 ` [PATCH 19/23] cgroup/cpuset: Improve check for calling housekeeping_update() Waiman Long
2026-04-23 1:10 ` Chen Ridong
2026-04-24 18:32 ` Waiman Long
2026-04-21 3:03 ` [PATCH 20/23] cgroup/cpuset: Enable runtime update of HK_TYPE_{KERNEL_NOISE,MANAGED_IRQ} cpumasks Waiman Long
2026-04-21 3:03 ` [PATCH 21/23] cgroup/cpuset: Limit the side effect of using CPU hotplug on isolated partition Waiman Long
2026-04-21 3:03 ` [PATCH 22/23] cgroup/cpuset: Prevent offline_disabled CPUs from being used in " Waiman Long
2026-04-21 3:03 ` [PATCH 23/23] cgroup/cpuset: Documentation and kselftest updates Waiman Long
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