From: Peter Zijlstra <peterz@infradead.org>
To: Jason Low <jason.low2@hp.com>
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>
Subject: Re: [RFC PATCH] timer: Improve itimers scalability
Date: Wed, 5 Aug 2015 11:37:19 +0200 [thread overview]
Message-ID: <20150805093719.GV25159@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1438734584.2927.15.camel@j-VirtualBox>
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)) {
> struct task_cputime group_sample;
>
> + /*
> + * If another thread in the group is already checking
> + * for the thread group cputimer, then we will skip that.
> + */
> + if (READ_ONCE(sig->cputimer.is_checking_timer))
> + return 0;
> +
> sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
>
> if (task_cputime_expired(&group_sample, &sig->cputime_expires))
next prev parent reply other threads:[~2015-08-05 9:37 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 [this message]
2015-08-05 19:44 ` Jason Low
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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