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From:   Lai Jiangshan <jiangshanlai@gmail.com>
Date:   Mon, 28 Nov 2022 11:24:38 +0800
Message-ID: <CAJhGHyCPbmEY_Azx056ePxO0B-GzUY3KXs3_UT6Z9XUAfVqS0A@mail.gmail.com>
Subject: Re: [PATCH] workqueue: Remove the unbound release work from the
 per-cpu type
To:     richard clark <richard.xnu.clark@gmail.com>
Cc:     tj@kernel.org, linux-kernel@vger.kernel.org
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On Fri, Nov 25, 2022 at 11:02 AM richard clark
<richard.xnu.clark@gmail.com> wrote:
>
> Hi Tejun,
>
> Would you pls help take a look at this? Or point to someone who is
> maintaining the workqueue subsystem, I can ping him/her...
>
> Richard

Hello, Richard

Thank you for reviewing the code of workqueue and trying to improve it.

But INIT_WORK() has no unwanted effect and it is better to initialize
the field even if it is unused.

The patch would not be accepted.

Thanks.
Lai

>
> On Wed, Nov 23, 2022 at 5:51 PM Richard Clark
> <richard.xnu.clark@gmail.com> wrote:
> >
> > Both the per-cpu and unbound workqueue will call init_pwq(...) currently,
> > the latter will init an unbound release work for the pwq which is unnecessary
> > for the per-cpu type workqueue.
> > This commit will remove this work item from the per-cpu workqueue by checking the
> > wq->flags in init_pwq(...), the work is still reserved for the unbound workqueue.
> >
> > Signed-off-by: Richard Clark <richard.xnu.clark@gmail.com>
> > Cc: Tejun Heo <tj@kernel.org>
> > Cc: Lai Jiangshan <jiangshanlai@gmail.com>
> > ---
> >  kernel/workqueue.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> > index 7cd5f5e7e0a1..01bdfb74081e 100644
> > --- a/kernel/workqueue.c
> > +++ b/kernel/workqueue.c
> > @@ -3807,7 +3807,8 @@ static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
> >         INIT_LIST_HEAD(&pwq->inactive_works);
> >         INIT_LIST_HEAD(&pwq->pwqs_node);
> >         INIT_LIST_HEAD(&pwq->mayday_node);
> > -       INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
> > +       if (wq->flags & WQ_UNBOUND)
> > +               INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
> >  }
> >
> >  /* sync @pwq with the current state of its associated wq and link it */
> > --
> > 2.37.2
> >