From: Lai Jiangshan <jiangshanlai@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [PATCH 1/2] workqueue: pin the pool while it is managing
Date: Fri, 29 May 2020 13:33:11 +0800 [thread overview]
Message-ID: <CAJhGHyDVkyouuNpSDiJ9nwxZAwKd7uGWf4PN6GXE2Y+3zENz0Q@mail.gmail.com> (raw)
In-Reply-To: <20200528143519.GN83516@mtj.thefacebook.com>
On Thu, May 28, 2020 at 10:35 PM Tejun Heo <tj@kernel.org> wrote:
>
> Hello,
>
> On Thu, May 28, 2020 at 03:06:55AM +0000, Lai Jiangshan wrote:
> > @@ -2129,10 +2128,21 @@ __acquires(&pool->lock)
> > static bool manage_workers(struct worker *worker)
> > {
> > struct worker_pool *pool = worker->pool;
> > + struct work_struct *work = list_first_entry(&pool->worklist,
> > + struct work_struct, entry);
>
> I'm not sure about this. It's depending on an external condition (active
> work item) which isn't obvious and when that condition breaks the resulting
> bug will be one which is difficult to reproduce. Adding to that, pwq isn't
> even the object this code path is interested in, which is the cause of the
> previous problem too.
Ok, I agree with you.
Thanks
Lai
next prev parent reply other threads:[~2020-05-29 5:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 19:46 [PATCH v2 0/2] workqueue: Make the workqueue code PREEMPT_RT safe Sebastian Andrzej Siewior
2020-05-27 19:46 ` [PATCH v2 1/2] workqueue: Use rcuwait for wq_manager_wait Sebastian Andrzej Siewior
2020-05-28 3:06 ` [PATCH 1/2] workqueue: pin the pool while it is managing Lai Jiangshan
2020-05-28 3:06 ` [PATCH 2/2] workqueue: remove useless POOL_MANAGER_ACTIVE Lai Jiangshan
2020-05-28 8:08 ` [PATCH 1/2] workqueue: pin the pool while it is managing Sebastian Andrzej Siewior
2020-05-28 8:35 ` Lai Jiangshan
2020-05-28 14:35 ` Tejun Heo
2020-05-29 5:33 ` Lai Jiangshan [this message]
2020-05-27 19:46 ` [PATCH v2 2/2] workqueue: Convert the pool::lock and wq_mayday_lock to raw_spinlock_t Sebastian Andrzej Siewior
2020-05-28 0:33 ` Lai Jiangshan
2020-05-29 14:04 ` Tejun Heo
2020-05-27 22:57 ` [PATCH v2 0/2] workqueue: Make the workqueue code PREEMPT_RT safe Linus Torvalds
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