Date: Wed, 29 Jul 2015 15:01:48 +0200
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Chris Metcalf <cmetcalf@ezchip.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Preeti U Murthy <preeti@linux.vnet.ibm.com>,
        Christoph Lameter <cl@linux.com>, Ingo Molnar <mingo@kernel.org>,
        Viresh Kumar <viresh.kumar@linaro.org>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 07/10] sched: Migrate sched to use new tick dependency
 mask model
Message-ID: <20150729130147.GB11554@lerouge>
References: <1437669735-8786-1-git-send-email-fweisbec@gmail.com>
 <1437669735-8786-8-git-send-email-fweisbec@gmail.com>
 <55B26E4A.80209@ezchip.com>
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On Fri, Jul 24, 2015 at 12:56:42PM -0400, Chris Metcalf wrote:
> On 07/23/2015 12:42 PM, Frederic Weisbecker wrote:
> >+static inline void sched_update_tick_dependency(struct rq *rq)
> >+{
> >+	int cpu;
> >+
> >+	if (!tick_nohz_full_enabled())
> >+		return;
> >+
> >+	cpu = cpu_of(rq);
> >+
> >+	if (!tick_nohz_full_cpu(rq->cpu))
> >+		return;
> >+
> >+	if (sched_can_stop_tick(rq))
> >+		tick_nohz_clear_tick_dependency_cpu(TICK_SCHED_BIT, cpu);
> >+	else
> >+		tick_nohz_set_tick_dependency_cpu(TICK_SCHED_BIT, cpu);
> >+}
> 
> Is it worth asserting that the rq is locked at this point? Presumably that's
> a requirement so that the cpu can't change out from under you.

Indeed it has become a requirement here. I'll add a check.

Thanks.
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