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From:   Lai Jiangshan <jiangshanlai@gmail.com>
Date:   Tue, 3 Nov 2020 12:35:07 +0800
Message-ID: <CAJhGHyAQPGnF1rkeeNEHSmqFBS0Ku2h3rEc5tLfm-rEs1A=MhA@mail.gmail.com>
Subject: Re: [PATCH 1/1] workqueue: Remove redundant assignment
To:     Adrian Huang <adrianhuang0701@gmail.com>
Cc:     Tejun Heo <tj@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Adrian Huang <ahuang12@lenovo.com>
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Hello, Adrian

I believe the pool->node is being used as a node hint
before workqueue_init() for allocating memory. It is
useful when it is correct.

I think it is better to init it early unless there is a bug
about it in this early stage reported (on same archs).

Thanks
Lai.

On Sun, Nov 1, 2020 at 8:21 PM Adrian Huang <adrianhuang0701@gmail.com> wrote:
>
> From: Adrian Huang <ahuang12@lenovo.com>
>
> The member 'node' of worker_pool struct (per_cpu worker_pool) is
> assigned in workqueue_init_early() and workqueue_init().
> Commit 2186d9f940b6 ("workqueue: move wq_numa_init() to workqueue_init()")
> fixes an issue by moving wq_numa_init() to workqueue_init() in order
> to get the valid 'cpu to node' mapping. So, remove the redundant
> assignment in workqueue_init_early().
>
> Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
> ---
>  kernel/workqueue.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 437935e7a199..cf8c0df2410e 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -5937,7 +5937,6 @@ void __init workqueue_init_early(void)
>                         pool->cpu = cpu;
>                         cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu));
>                         pool->attrs->nice = std_nice[i++];
> -                       pool->node = cpu_to_node(cpu);
>
>                         /* alloc pool ID */
>                         mutex_lock(&wq_pool_mutex);
> --
> 2.17.1
>