netdev - Re: [PATCH] team: add rescheduling jiffy delay on !rtnl

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Message-ID: <20141005021325.GB8549@htj.dyndns.org>
Date:	Sat, 4 Oct 2014 22:13:25 -0400
From:	Tejun Heo <tj@...nel.org>
To:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc:	Joe Lawrence <joe.lawrence@...atus.com>, netdev@...r.kernel.org,
	Jiri Pirko <jiri@...nulli.us>
Subject: Re: [PATCH] team: add rescheduling jiffy delay on !rtnl_trylock

Hello,

On Sat, Oct 04, 2014 at 01:37:32AM -0700, Paul E. McKenney wrote:
> On Fri, Oct 03, 2014 at 03:37:01PM -0400, Joe Lawrence wrote:
> > I gave this a spin, probably inserting the call in the wrong place:
> > 
> > diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> > index 5dbe22a..77f128e 100644
> > --- a/kernel/workqueue.c
> > +++ b/kernel/workqueue.c
> > @@ -2045,7 +2045,8 @@ __acquires(&pool->lock)
> >          * indefinitely requeue itself while all other CPUs are trapped in
> >          * stop_machine.
> >          */
> > -       cond_resched();
> > +       if (!cond_resched())
> > +               rcu_note_context_switch(raw_smp_processor_id());
> > 
> >         spin_lock_irq(&pool->lock);
> 
> If the cond_resched() is in the right place, then you should be good.

Yeah, it looks good to me.

> FWIW, there is a cond_resched_rcu_qs() that should be going into the next
> merge window that could be used in place of the above two lines.  This is
> commit bde6c3aa9930 in -tip.

That sounds even better.

Joe, can you please send a patch with proper SOB and description?

Thanks.

-- 
tejun
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