Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker()

From	Tejun Heo <tj@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker()
Date	2016-06-24 18:00 +0200
Message-ID	<rNBGq-1Ax-3@gated-at.bofh.it> (permalink)
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Hello,

On Fri, Jun 24, 2016 at 09:05:15AM +0200, Peter Zijlstra wrote:
> > Given how rare that is 
> 
> Could you then not remove/rework these few cases for workqueue as well
> and make that 'better' too?

Usage of draining is rare for workqueue but that still means several
legitimate users.  With draining there, it's logical to use it during
shutdown.  I don't think it makes sense to change it on workqueue
side.

> > and the extra
> > complexity of identifying self-requeueing cases, let's forget about
> > draining and on destruction clear the worker pointer to block further
> > queueing and then flush whatever is in flight.
> 
> You're talking about regular workqueues here?

No, kthread worker.  It's unlikely that kthread worker is gonna need
chained draining especially given that most of its usages are gonna be
conversions from raw kthread usages.  We won't lose much if anything
by just ignoring draining and making the code simpler.

Thanks.

-- 
tejun

Thread

Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker() Tejun Heo <tj@kernel.org> - 2016-06-23 23:40 +0200
  Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker() Peter Zijlstra <peterz@infradead.org> - 2016-06-24 09:10 +0200
    Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker() Petr Mladek <pmladek@suse.com> - 2016-06-24 11:10 +0200
    Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker() Tejun Heo <tj@kernel.org> - 2016-06-24 18:00 +0200
      Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker() Petr Mladek <pmladek@suse.com> - 2016-06-27 16:40 +0200
        Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker() Tejun Heo <tj@kernel.org> - 2016-06-28 19:10 +0200
          Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker() Petr Mladek <pmladek@suse.com> - 2016-06-29 10:20 +0200
            Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker() Tejun Heo <tj@kernel.org> - 2016-06-29 15:20 +0200

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