From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: paulmck@linux.vnet.ibm.com
Cc: peterz@infradead.org, mingo@elte.hu, josh@joshtriplett.org,
laijs@cn.fujitsu.com, linux-kernel@vger.kernel.org
Subject: Re: cond_resched() and RCU CPU stall warnings
Date: Sun, 16 Mar 2014 08:30:20 +0100 [thread overview]
Message-ID: <1394955020.19079.3.camel@marge.simpson.net> (raw)
In-Reply-To: <20140316062501.GX21124@linux.vnet.ibm.com>
On Sat, 2014-03-15 at 23:25 -0700, Paul E. McKenney wrote:
> On Sun, Mar 16, 2014 at 07:09:42AM +0100, Mike Galbraith wrote:
> > Hm. Since you only care about the case where your task is solo, how
> > about do racy checks, 100% accuracy isn't required is it? Seems you
> > wouldn't want to unconditionally do that in tight loops.
>
> And indeed, my current workaround unconditionally does schedule() one
> out of 256 loops. I would do something similar here, perhaps based
> on per-CPU counters, perhaps even with racy accesses to avoid always
> doing preempt_disable()/preempt_enable().
>
> Or did you have something else in mind?
Exactly what I meant, take a racy peek or two first.
-Mike
next prev parent reply other threads:[~2014-03-16 7:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-16 1:59 cond_resched() and RCU CPU stall warnings Paul E. McKenney
2014-03-16 6:09 ` Mike Galbraith
2014-03-16 6:14 ` Mike Galbraith
2014-03-16 6:27 ` Paul E. McKenney
2014-03-16 6:25 ` Paul E. McKenney
2014-03-16 7:30 ` Mike Galbraith [this message]
2014-03-17 10:13 ` Peter Zijlstra
2014-03-17 16:58 ` Paul E. McKenney
2014-03-17 17:14 ` Peter Zijlstra
2014-03-18 2:17 ` Paul E. McKenney
2014-03-18 8:51 ` Peter Zijlstra
2014-03-18 12:49 ` Paul E. McKenney
2014-03-18 13:45 ` Peter Zijlstra
2014-03-18 15:15 ` Paul E. McKenney
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