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From: Peter Zijlstra <peterz@infradead.org>
To: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: linux-kernel@vger.kernel.org,
	Lai Jiangshan <laijs@linux.alibaba.com>,
	Tejun Heo <tj@kernel.org>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>
Subject: Re: [PATCH 02/10] workqueue: use cpu_possible_mask instead of cpu_active_mask to break affinity
Date: Mon, 14 Dec 2020 18:25:34 +0100	[thread overview]
Message-ID: <X9egDheiQPLdR0IS@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201214155457.3430-3-jiangshanlai@gmail.com>

On Mon, Dec 14, 2020 at 11:54:49PM +0800, Lai Jiangshan wrote:
> From: Lai Jiangshan <laijs@linux.alibaba.com>
> 
> There might be other CPU online. The workers losing binding on its CPU
> should have chance to work on those later onlined CPUs.
> 
> Fixes: 06249738a41a ("workqueue: Manually break affinity on hotplug")
> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
> ---
>  kernel/workqueue.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index aba71ab359dd..1f5b8385c0cf 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -4909,8 +4909,9 @@ static void unbind_workers(int cpu)
>  
>  		raw_spin_unlock_irq(&pool->lock);
>  
> +		/* don't rely on the scheduler to force break affinity for us. */
>  		for_each_pool_worker(worker, pool)
> -			WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_active_mask) < 0);
> +			WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0);

Please explain this one.. it's not making sense. Also the Changelog
doesn't seem remotely related to the actual change.

Afaict this is actively wrong.

Also, can you please not Cc me parts of a series? That's bloody
annoying.

  reply	other threads:[~2020-12-14 17:33 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-14 15:54 [PATCH 00/10] workqueue: break affinity initiatively Lai Jiangshan
2020-12-14 15:54 ` [PATCH 01/10] workqueue: restore unbound_workers' cpumask correctly Lai Jiangshan
2020-12-14 15:54 ` [PATCH 02/10] workqueue: use cpu_possible_mask instead of cpu_active_mask to break affinity Lai Jiangshan
2020-12-14 17:25   ` Peter Zijlstra [this message]
2020-12-15  8:33     ` Lai Jiangshan
2020-12-15  8:40     ` Peter Zijlstra
2020-12-16 14:32   ` Tejun Heo
2020-12-14 15:54 ` [PATCH 03/10] workqueue: Manually break affinity on pool detachment Lai Jiangshan
2020-12-14 15:54 ` [PATCH 04/10] workqueue: don't set the worker's cpumask when kthread_bind_mask() Lai Jiangshan
2020-12-16 14:39   ` Tejun Heo
2020-12-14 15:54 ` [PATCH 05/10] workqueue: introduce wq_online_cpumask Lai Jiangshan
2020-12-14 15:54 ` [PATCH 06/10] workqueue: use wq_online_cpumask in restore_unbound_workers_cpumask() Lai Jiangshan
2020-12-14 15:54 ` [PATCH 07/10] workqueue: Manually break affinity on hotplug for unbound pool Lai Jiangshan
2020-12-16 14:50   ` Tejun Heo
2020-12-14 15:54 ` [PATCH 08/10] workqueue: reorganize workqueue_online_cpu() Lai Jiangshan
2020-12-14 15:54 ` [PATCH 09/10] workqueue: reorganize workqueue_offline_cpu() unbind_workers() Lai Jiangshan
2020-12-14 15:54 ` [PATCH 10/10] workqueue: Fix affinity of kworkers when attaching into pool Lai Jiangshan
2020-12-15 15:03   ` Valentin Schneider
2020-12-14 17:36 ` [PATCH 00/10] workqueue: break affinity initiatively Peter Zijlstra
2020-12-15  5:44   ` Lai Jiangshan
2020-12-15  7:50     ` Peter Zijlstra
2020-12-15  8:14       ` Lai Jiangshan
2020-12-15  8:49         ` Peter Zijlstra
2020-12-15  9:46           ` Lai Jiangshan
2020-12-16 14:30 ` Tejun Heo

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