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From: Viresh Kumar <viresh.kumar@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
	ashwin.chaugule@linaro.org,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers
Date: Tue, 8 Dec 2015 19:00:36 +0530	[thread overview]
Message-ID: <20151208133036.GB3692@ubuntu> (raw)
In-Reply-To: <7208072.lZriMRM1aD@vostro.rjw.lan>

On 08-12-15, 14:18, Rafael J. Wysocki wrote:
> Well, if the timer function runs on all CPUs at the same time, they all
> can see skip_work > 1 and none of them will queue the work.

You are talking about code after my patch, right?

Will will all of them see it > 1? At least one of them will see it 0
and queue the work, unless the governor is stopped completely.

> You are right, I've overlooked that race (but then it is rather easy to
> overlook).

Yeah, we (at least I) took a long time to understand that this was the
real problem we always had and so fixed it recently.

-- 
viresh

  reply	other threads:[~2015-12-08 13:30 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1449115453.git.viresh.kumar@linaro.org>
2015-12-03  4:07 ` [PATCH V2 1/6] cpufreq: ondemand: Update sampling rate only for concerned policies Viresh Kumar
2015-12-03  4:07 ` [PATCH V2 2/6] cpufreq: ondemand: Work is guaranteed to be pending Viresh Kumar
2015-12-03  4:07 ` [PATCH V2 3/6] cpufreq: governor: Pass policy as argument to ->gov_dbs_timer() Viresh Kumar
2015-12-03  4:07 ` [PATCH V2 4/6] cpufreq: governor: initialize/destroy timer_mutex with 'shared' Viresh Kumar
2015-12-03  4:07 ` [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers Viresh Kumar
2015-12-04  1:18   ` Rafael J. Wysocki
2015-12-04  6:11     ` Viresh Kumar
2015-12-05  2:14       ` Rafael J. Wysocki
2015-12-05  4:10         ` Viresh Kumar
2015-12-07  1:28           ` Rafael J. Wysocki
2015-12-07  7:50             ` Viresh Kumar
2015-12-07 22:43               ` Rafael J. Wysocki
2015-12-07 23:17                 ` Rafael J. Wysocki
2015-12-08  0:39                   ` [PATCH][experimantal] cpufreq: governor: Use an atomic variable for synchronization Rafael J. Wysocki
2015-12-08  6:59                     ` Viresh Kumar
2015-12-08 13:30                       ` Rafael J. Wysocki
2015-12-08 13:36                         ` Viresh Kumar
2015-12-08 14:19                           ` Rafael J. Wysocki
2015-12-08 13:55                             ` Viresh Kumar
2015-12-08 14:30                               ` Rafael J. Wysocki
2015-12-08 14:56                                 ` Viresh Kumar
2015-12-08 16:42                                   ` Rafael J. Wysocki
2015-12-08 16:34                                     ` Viresh Kumar
2015-12-08  6:46                   ` [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers Viresh Kumar
2015-12-08  6:56                 ` Viresh Kumar
2015-12-08 13:18                   ` Rafael J. Wysocki
2015-12-08 13:30                     ` Viresh Kumar [this message]
2015-12-08 14:04                       ` Rafael J. Wysocki
2015-12-04  6:13   ` [PATCH V3 " Viresh Kumar
2015-12-09  2:04     ` [PATCH V4 " Viresh Kumar
2015-12-09 22:06       ` Rafael J. Wysocki
2015-12-10  2:36         ` Viresh Kumar
2015-12-10 22:17           ` Rafael J. Wysocki
2015-12-11  1:42             ` Viresh Kumar
2015-12-03  4:07 ` [PATCH V2 6/6] cpufreq: ondemand: update update_sampling_rate() to make it more efficient Viresh Kumar

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