From: Jason Low <jason.low2@hp.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org,
Frederic Weisbecker <fweisbec@gmail.com>,
Oleg Nesterov <oleg@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
terry.rudd@hp.com, Rik van Riel <riel@redhat.com>,
Waiman Long <Waiman.Long@hp.com>,
Scott J Norton <scott.norton@hp.com>,
jason.low2@hp.com
Subject: Re: [RFC PATCH] timer: Improve itimers scalability
Date: Wed, 05 Aug 2015 12:44:41 -0700 [thread overview]
Message-ID: <1438803881.4833.34.camel@j-VirtualBox> (raw)
In-Reply-To: <20150805093719.GV25159@twins.programming.kicks-ass.net>
On Wed, 2015-08-05 at 11:37 +0200, Peter Zijlstra wrote:
> On Tue, Aug 04, 2015 at 05:29:44PM -0700, Jason Low wrote:
>
> > @@ -1137,6 +1148,13 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
> > if (READ_ONCE(sig->cputimer.running)) {
>
> Maybe make that:
>
> if (READ_ONCE(sig->cputimer.running) &&
> !READ_ONCE(sig->cputimer.is_checking_timer)) {
Yes, I think it would be better if the check is done here.
And perhaps the comment can be modified to:
/*
* Check if thread group timers expired. This is skipped if the cputimer
* is not running or if another thread in the group is already checking
* for thread group cputimers.
*/
next prev parent reply other threads:[~2015-08-05 19:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-05 0:29 [RFC PATCH] timer: Improve itimers scalability Jason Low
2015-08-05 9:24 ` Peter Zijlstra
2015-08-05 9:37 ` Peter Zijlstra
2015-08-05 19:44 ` Jason Low [this message]
2015-08-06 14:18 ` Oleg Nesterov
2015-08-06 18:21 ` Jason Low
2015-08-07 12:01 ` Oleg Nesterov
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