linux-kernel - Re: [PATCH v2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend

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Date:	Tue, 15 Jul 2014 11:22:40 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Saravana Kannan <skannan@...eaurora.org>
Cc:	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Todd Poynor <toddpoynor@...gle.com>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Stephen Boyd <sboyd@...eaurora.org>
Subject: Re: [PATCH v2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend

On 15 July 2014 11:06, Saravana Kannan <skannan@...eaurora.org> wrote:
> Btw, I tried to take a stab at removing any assumption in cpufreq code about
> policy->cpu being ONLINE. There are 160 instances of those of with 23 are in
> cpufreq.c
>
> So, even if we are sure cpufreq.c is fine, it's 137 other uses spread across
> all the other files. I definitely don't want to try and fix those as part of
> this patch. Way too risky and hard to get the test coverage it would need.
> Even some of the acpi cpufreq drivers seem to be making this assumption.

Hmm, yeah that would be an issue. So this is what you should do now:
- Left policy->cpu as it is, i.e. updated only when policy->cpu goes down.
- Just make sure sysfs nodes are untouched when any cpu goes down

> Btw, I think v3 is done. I did some testing and it was fine. But made some
> minor changes. Will test tomorrow to make sure I didn't break anything with
> the minor changes and then send them out.

Ok, just comply to the above comments.
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