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From: Peter Zijlstra <peterz@infradead.org>
To: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Ingo Molnar <mingo@redhat.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linaro-kernel@lists.linaro.org
Subject: Re: [PATCH v2 1/2] sched: let the scheduler see CPU idle states
Date: Fri, 19 Sep 2014 01:17:15 +0200	[thread overview]
Message-ID: <20140918231715.GO2848@worktop.localdomain> (raw)
In-Reply-To: <alpine.LFD.2.11.1409181425080.8647@knanqh.ubzr>

On Thu, Sep 18, 2014 at 02:32:25PM -0400, Nicolas Pitre wrote:
> On Thu, 18 Sep 2014, Paul E. McKenney wrote:

> > So what is it that you really need to do here?
> 
> In short, we don't want the cpufreq data to go away (see the 2 scenarios 
> above) while the scheduler is looking at it.  The scheduler uses the 
> provided accessors (see patch 2/2) so we can put any protection 
> mechanism we want in them.  A simple spinlock could do just as well 
> which should be good enough.

rq->lock disables interrupts so on that something like
kick_all_cpus_sync() will guarantee what you need --
wake_up_all_idle_cpus() will not.

  reply	other threads:[~2014-09-18 23:17 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-04 15:32 [PATCH v2 0/2] sched/idle : find the best idle CPU with cpuidle info Nicolas Pitre
2014-09-04 15:32 ` [PATCH v2 1/2] sched: let the scheduler see CPU idle states Nicolas Pitre
2014-09-18 17:37   ` Paul E. McKenney
2014-09-18 17:39     ` Paul E. McKenney
2014-09-18 23:15       ` Peter Zijlstra
2014-09-18 18:32     ` Nicolas Pitre
2014-09-18 23:17       ` Peter Zijlstra [this message]
2014-09-18 23:28         ` Peter Zijlstra
2014-09-19 18:30           ` Nicolas Pitre
2014-09-04 15:32 ` [PATCH v2 2/2] sched/fair: leverage the idle state info when choosing the "idlest" cpu Nicolas Pitre
2014-09-05  7:52   ` Daniel Lezcano
2014-09-18 23:46   ` Peter Zijlstra
2014-09-19  0:05   ` Peter Zijlstra
2014-09-19  4:49   ` Yao Dongdong
2014-09-30 21:58   ` Rik van Riel
2014-09-30 23:15     ` Nicolas Pitre
2014-10-02 17:15       ` [PATCH RFC] sched,idle: teach select_idle_sibling about idle states Rik van Riel
2014-10-03  6:04         ` Mike Galbraith
2014-10-03  6:23         ` Mike Galbraith
2014-10-03  7:50           ` Peter Zijlstra
2014-10-03 13:05             ` Mike Galbraith
2014-10-03 14:28             ` Rik van Riel
2014-10-03 14:46               ` Peter Zijlstra
2014-10-03 15:37                 ` Rik van Riel
2014-10-09 16:04                   ` Peter Zijlstra
2014-10-03 18:52               ` Nicolas Pitre
2014-09-10 21:35 ` [PATCH v2 0/2] sched/idle : find the best idle CPU with cpuidle info Nicolas Pitre
2014-09-10 22:50   ` Rafael J. Wysocki
2014-09-10 23:25     ` Nicolas Pitre
2014-09-10 23:28       ` Nicolas Pitre
2014-09-10 23:50       ` Rafael J. Wysocki
2014-09-18  0:39   ` Nicolas Pitre
2014-09-18 23:24     ` Peter Zijlstra
2014-09-19 18:22       ` Nicolas Pitre

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