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Date: Fri, 5 Feb 2016 04:33:05 +0100
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Subject: Re: [PATCH 2/11] cpufreq: governor: Use common mutex for dbs_data protection
From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Linux PM list <linux-pm@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Juri Lelli <juri.lelli@arm.com>,
        Steve Muckle <steve.muckle@linaro.org>,
        Saravana Kannan <skannan@codeaurora.org>
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On Fri, Feb 5, 2016 at 4:24 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 05-02-16, 04:17, Rafael J. Wysocki wrote:
>> And don't we switch governors under policy->rwsem anyway?
>
> So ? That is blocking only a single policy only, but with the new
> change, we will block all policies from doing that concurrently.

No, it won't.  Again: one lock instead of two.  How much of a
difference this makes performance-wise?

And the price is the stupid dance we need to do to even get to those
locks!  Come on.

Thanks,
Rafael