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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
	linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH 02/10] cpufreq: conservative: Avoid races with transition notifier
Date: Wed, 24 Jun 2015 06:41:51 +0530	[thread overview]
Message-ID: <20150624011151.GC6424@linux> (raw)
In-Reply-To: <55898105.2050907@linux.vnet.ibm.com>

On 23-06-15, 21:23, Preeti U Murthy wrote:
> On 06/22/2015 01:32 PM, Viresh Kumar wrote:
> > It is possible that cpufreq transition notifier is called while the
> > governor is performing its EXIT operation. If this happens, 'ccdbs'
> 
> When does this happen ? As far as I can see, cpufreq transition notifier
> gets called from the cpufreq kworker or when we set the cpufreq limits.

Which kworker are you talking about here ? The work-handlers of
ondemand/conservative governors ?

Conservative governor has registered for transition notifier and that
will be called every time frequency of a CPU is updated. And that has
nothing to do with the governor callbacks. These notifiers are called
from the ->target() routines of the drivers.

> And from your previous patches, an exit operation only proceeds after
> ensuring that no kworker is running (check on ccdbs->policy). And LIMIT
> operation does not run in parallel too.

Does it look better from the earlier description?

-- 
viresh

  reply	other threads:[~2015-06-24  1:11 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-22  8:02 [PATCH 00/10] cpufreq: governor: Further cleanups (v4.3) Viresh Kumar
2015-06-22  8:02 ` [PATCH 01/10] cpufreq: Use __func__ to print function's name Viresh Kumar
2015-06-23 15:39   ` Preeti U Murthy
2015-06-22  8:02 ` [PATCH 02/10] cpufreq: conservative: Avoid races with transition notifier Viresh Kumar
2015-06-23 15:53   ` Preeti U Murthy
2015-06-24  1:11     ` Viresh Kumar [this message]
2015-06-25  7:59       ` Viresh Kumar
2015-06-22  8:02 ` [PATCH 03/10] cpufreq: conservative: remove 'enable' field Viresh Kumar
2015-06-26  5:57   ` Preeti U Murthy
2015-06-26  6:19     ` Viresh Kumar
2015-06-22  8:02 ` [PATCH 04/10] cpufreq: ondemand: only queue canceled works from update_sampling_rate() Viresh Kumar
2015-06-26  6:50   ` Preeti U Murthy
2015-06-26  7:28     ` Viresh Kumar
2015-06-22  8:02 ` [PATCH 05/10] cpufreq: governor: Drop __gov_queue_work() Viresh Kumar
2015-06-26  7:03   ` Preeti U Murthy
2015-06-26  7:32     ` Viresh Kumar
2015-06-22  8:02 ` [PATCH 06/10] cpufreq: ondemand: Drop unnecessary locks from update_sampling_rate() Viresh Kumar
2015-06-26  7:20   ` Preeti U Murthy
2015-06-22  8:02 ` [PATCH 07/10] cpufreq: ondemand: queue work for policy->cpus together Viresh Kumar
2015-06-26  8:28   ` Preeti U Murthy
2015-06-26  8:52     ` Viresh Kumar
2015-06-22  8:02 ` [PATCH 08/10] cpufreq: ondemand: update sampling rate immidiately Viresh Kumar
2015-06-22  8:02 ` [PATCH 09/10] cpufreq: governor: Quit work-handlers early if governor is stopped Viresh Kumar
2015-06-22  8:02 ` [PATCH 10/10] cpufreq: Get rid of ->governor_enabled and its lock Viresh Kumar

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