From: Saravana Kannan <skannan@codeaurora.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
Todd Poynor <toddpoynor@google.com>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Stephen Boyd <sboyd@codeaurora.org>
Subject: Re: [PATCH v2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend
Date: Mon, 14 Jul 2014 22:36:59 -0700 [thread overview]
Message-ID: <53C4BDFB.70707@codeaurora.org> (raw)
In-Reply-To: <CAKohpomkqbHZo9KrJMSwsEKGt6+Ac2Fg2X0+S7ZAo=OzhAc45g@mail.gmail.com>
On 07/14/2014 09:35 PM, Viresh Kumar wrote:
> On 15 July 2014 00:38, Saravana Kannan <skannan@codeaurora.org> wrote:
>> Yeah, it definitely crashes if policy->cpu if an offline cpu. Because the
>> mutex would be uninitialized if it's stopped after boot or it would never
>> have been initialized (depending on how you fix policy->cpu at boot).
>>
>> Look at this snippet on the actual tree and it should be pretty evident.
>
> Yeah, I missed it. So the problem is we initialize timer_mutex's for
> policy->cpus. So we need to do that just for policy->cpu and also we don't
> need a per-cpu timer_mutex anymore.
>
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.
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.
-Saravana
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation
WARNING: multiple messages have this Message-ID (diff)
From: skannan@codeaurora.org (Saravana Kannan)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend
Date: Mon, 14 Jul 2014 22:36:59 -0700 [thread overview]
Message-ID: <53C4BDFB.70707@codeaurora.org> (raw)
In-Reply-To: <CAKohpomkqbHZo9KrJMSwsEKGt6+Ac2Fg2X0+S7ZAo=OzhAc45g@mail.gmail.com>
On 07/14/2014 09:35 PM, Viresh Kumar wrote:
> On 15 July 2014 00:38, Saravana Kannan <skannan@codeaurora.org> wrote:
>> Yeah, it definitely crashes if policy->cpu if an offline cpu. Because the
>> mutex would be uninitialized if it's stopped after boot or it would never
>> have been initialized (depending on how you fix policy->cpu at boot).
>>
>> Look at this snippet on the actual tree and it should be pretty evident.
>
> Yeah, I missed it. So the problem is we initialize timer_mutex's for
> policy->cpus. So we need to do that just for policy->cpu and also we don't
> need a per-cpu timer_mutex anymore.
>
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.
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.
-Saravana
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation
next prev parent reply other threads:[~2014-07-15 5:36 UTC|newest]
Thread overview: 205+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-10 2:37 [PATCH] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend Saravana Kannan
2014-07-10 2:37 ` Saravana Kannan
2014-07-11 4:18 ` [PATCH v2] " Saravana Kannan
2014-07-11 4:18 ` Saravana Kannan
2014-07-11 6:19 ` Viresh Kumar
2014-07-11 6:19 ` Viresh Kumar
2014-07-11 6:19 ` Viresh Kumar
2014-07-11 9:59 ` skannan
2014-07-11 9:59 ` skannan at codeaurora.org
2014-07-11 9:59 ` skannan
2014-07-11 10:07 ` skannan
2014-07-11 10:07 ` skannan at codeaurora.org
2014-07-11 10:07 ` skannan
2014-07-11 10:52 ` Viresh Kumar
2014-07-11 10:52 ` Viresh Kumar
2014-07-11 10:52 ` Viresh Kumar
2014-07-12 2:44 ` Saravana Kannan
2014-07-12 2:44 ` Saravana Kannan
2014-07-12 2:44 ` Saravana Kannan
2014-07-14 6:09 ` Viresh Kumar
2014-07-14 6:09 ` Viresh Kumar
2014-07-14 6:09 ` Viresh Kumar
2014-07-14 19:08 ` Saravana Kannan
2014-07-14 19:08 ` Saravana Kannan
2014-07-14 19:08 ` Saravana Kannan
2014-07-15 4:35 ` Viresh Kumar
2014-07-15 4:35 ` Viresh Kumar
2014-07-15 4:35 ` Viresh Kumar
2014-07-15 5:36 ` Saravana Kannan [this message]
2014-07-15 5:36 ` Saravana Kannan
2014-07-15 5:36 ` Saravana Kannan
2014-07-15 5:52 ` Viresh Kumar
2014-07-15 5:52 ` Viresh Kumar
2014-07-15 5:52 ` Viresh Kumar
2014-07-15 6:58 ` Srivatsa S. Bhat
2014-07-15 6:58 ` Srivatsa S. Bhat
2014-07-15 6:58 ` Srivatsa S. Bhat
2014-07-15 17:35 ` skannan
2014-07-15 17:35 ` skannan at codeaurora.org
2014-07-15 17:35 ` skannan
2014-07-16 7:44 ` Srivatsa S. Bhat
2014-07-16 7:44 ` Srivatsa S. Bhat
2014-07-16 7:44 ` Srivatsa S. Bhat
2014-07-16 5:44 ` Viresh Kumar
2014-07-16 5:44 ` Viresh Kumar
2014-07-16 5:44 ` Viresh Kumar
2014-07-16 7:49 ` Srivatsa S. Bhat
2014-07-16 7:49 ` Srivatsa S. Bhat
2014-07-16 7:49 ` Srivatsa S. Bhat
2014-07-12 3:06 ` Saravana Kannan
2014-07-12 3:06 ` Saravana Kannan
2014-07-12 3:06 ` Saravana Kannan
2014-07-14 6:13 ` Viresh Kumar
2014-07-14 6:13 ` Viresh Kumar
2014-07-14 6:13 ` Viresh Kumar
2014-07-14 19:10 ` Saravana Kannan
2014-07-14 19:10 ` Saravana Kannan
2014-07-14 19:10 ` Saravana Kannan
2014-07-11 7:43 ` Srivatsa S. Bhat
2014-07-11 7:43 ` Srivatsa S. Bhat
2014-07-11 10:02 ` skannan
2014-07-11 10:02 ` skannan at codeaurora.org
2014-07-15 22:47 ` [PATCH v3 0/2] Simplify hotplug/suspend handling Saravana Kannan
2014-07-15 22:47 ` Saravana Kannan
2014-07-15 22:47 ` [PATCH v3 1/2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend Saravana Kannan
2014-07-15 22:47 ` Saravana Kannan
2014-07-16 0:28 ` Saravana Kannan
2014-07-16 0:28 ` Saravana Kannan
2014-07-16 8:30 ` Viresh Kumar
2014-07-16 8:30 ` Viresh Kumar
2014-07-16 8:30 ` Viresh Kumar
2014-07-16 19:19 ` Saravana Kannan
2014-07-16 19:19 ` Saravana Kannan
2014-07-16 19:19 ` Saravana Kannan
2014-07-16 8:24 ` Viresh Kumar
2014-07-16 8:24 ` Viresh Kumar
2014-07-16 8:24 ` Viresh Kumar
2014-07-16 11:16 ` Srivatsa S. Bhat
2014-07-16 11:16 ` Srivatsa S. Bhat
2014-07-16 11:16 ` Srivatsa S. Bhat
2014-07-16 13:13 ` Viresh Kumar
2014-07-16 13:13 ` Viresh Kumar
2014-07-16 13:13 ` Viresh Kumar
2014-07-16 18:04 ` Srivatsa S. Bhat
2014-07-16 18:04 ` Srivatsa S. Bhat
2014-07-16 18:04 ` Srivatsa S. Bhat
2014-07-16 19:56 ` Saravana Kannan
2014-07-16 19:56 ` Saravana Kannan
2014-07-16 19:56 ` Saravana Kannan
2014-07-17 5:51 ` Viresh Kumar
2014-07-17 5:51 ` Viresh Kumar
2014-07-17 5:51 ` Viresh Kumar
2014-07-16 19:56 ` Saravana Kannan
2014-07-16 19:56 ` Saravana Kannan
2014-07-16 19:56 ` Saravana Kannan
2014-07-17 5:35 ` Viresh Kumar
2014-07-17 5:35 ` Viresh Kumar
2014-07-17 5:35 ` Viresh Kumar
2014-07-18 3:25 ` Saravana Kannan
2014-07-18 3:25 ` Saravana Kannan
2014-07-18 3:25 ` Saravana Kannan
2014-07-18 4:19 ` Viresh Kumar
2014-07-18 4:19 ` Viresh Kumar
2014-07-18 4:19 ` Viresh Kumar
2014-07-16 20:25 ` Saravana Kannan
2014-07-16 20:25 ` Saravana Kannan
2014-07-16 20:25 ` Saravana Kannan
2014-07-16 21:45 ` Saravana Kannan
2014-07-16 21:45 ` Saravana Kannan
2014-07-16 21:45 ` Saravana Kannan
2014-07-17 6:24 ` Viresh Kumar
2014-07-17 6:24 ` Viresh Kumar
2014-07-17 6:24 ` Viresh Kumar
2014-07-16 14:29 ` Dirk Brandewie
2014-07-16 14:29 ` Dirk Brandewie
2014-07-16 15:28 ` Viresh Kumar
2014-07-16 15:28 ` Viresh Kumar
2014-07-16 15:28 ` Viresh Kumar
2014-07-16 19:42 ` Saravana Kannan
2014-07-16 19:42 ` Saravana Kannan
2014-07-16 19:42 ` Saravana Kannan
2014-07-15 22:47 ` [PATCH v3 2/2] cpufreq: Simplify and fix mutual exclusion with hotplug Saravana Kannan
2014-07-15 22:47 ` Saravana Kannan
2014-07-16 8:48 ` Viresh Kumar
2014-07-16 8:48 ` Viresh Kumar
2014-07-16 8:48 ` Viresh Kumar
2014-07-16 19:34 ` Saravana Kannan
2014-07-16 19:34 ` Saravana Kannan
2014-07-16 19:34 ` Saravana Kannan
2014-07-25 1:07 ` [PATCH v4 0/5] Simplify hotplug/suspend handling Saravana Kannan
2014-07-25 1:07 ` Saravana Kannan
2014-07-25 1:07 ` [PATCH v4 1/5] cpufreq: Don't wait for CPU to going offline to restart governor Saravana Kannan
2014-07-25 1:07 ` Saravana Kannan
2014-07-31 20:47 ` Saravana Kannan
2014-07-31 20:47 ` Saravana Kannan
2014-07-25 1:07 ` [PATCH v4 2/5] cpufreq: Keep track of which CPU owns the kobj/sysfs nodes separately Saravana Kannan
2014-07-25 1:07 ` Saravana Kannan
2014-08-07 9:02 ` Viresh Kumar
2014-08-07 9:02 ` Viresh Kumar
2014-08-07 9:02 ` Viresh Kumar
2014-07-25 1:07 ` [PATCH v4 3/5] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend Saravana Kannan
2014-07-25 1:07 ` Saravana Kannan
2014-07-31 21:56 ` Rafael J. Wysocki
2014-07-31 21:56 ` Rafael J. Wysocki
2014-07-31 22:15 ` Saravana Kannan
2014-07-31 22:15 ` Saravana Kannan
2014-07-31 23:48 ` Saravana Kannan
2014-07-31 23:48 ` Saravana Kannan
2014-07-31 23:48 ` Saravana Kannan
2014-08-07 10:51 ` Viresh Kumar
2014-08-07 10:51 ` Viresh Kumar
2014-08-07 10:51 ` Viresh Kumar
2014-08-12 9:17 ` Viresh Kumar
2014-08-12 9:17 ` Viresh Kumar
2014-08-12 9:17 ` Viresh Kumar
2014-08-07 10:48 ` Viresh Kumar
2014-08-07 10:48 ` Viresh Kumar
2014-08-07 10:48 ` Viresh Kumar
2014-08-11 22:13 ` Saravana Kannan
2014-08-11 22:13 ` Saravana Kannan
2014-08-11 22:13 ` Saravana Kannan
2014-08-12 8:51 ` Viresh Kumar
2014-08-12 8:51 ` Viresh Kumar
2014-08-12 8:51 ` Viresh Kumar
2014-07-25 1:07 ` [PATCH v4 4/5] cpufreq: Properly handle physical CPU hot-add/hot-remove Saravana Kannan
2014-07-25 1:07 ` Saravana Kannan
2014-07-25 1:07 ` Saravana Kannan
2014-08-07 11:02 ` Viresh Kumar
2014-08-07 11:02 ` Viresh Kumar
2014-08-07 11:02 ` Viresh Kumar
2014-08-11 22:15 ` Saravana Kannan
2014-08-11 22:15 ` Saravana Kannan
2014-08-11 22:15 ` Saravana Kannan
2014-07-25 1:07 ` [PATCH v4 5/5] cpufreq: Delete dead code related to policy save/restore Saravana Kannan
2014-07-25 1:07 ` Saravana Kannan
2014-08-07 11:06 ` Viresh Kumar
2014-08-07 11:06 ` Viresh Kumar
2014-08-07 11:06 ` Viresh Kumar
2014-07-29 5:52 ` [PATCH v4 0/5] Simplify hotplug/suspend handling skannan
2014-07-29 5:52 ` skannan at codeaurora.org
2014-07-29 5:52 ` skannan
2014-07-30 0:29 ` Rafael J. Wysocki
2014-07-30 0:29 ` Rafael J. Wysocki
2014-07-31 20:25 ` Saravana Kannan
2014-07-31 20:25 ` Saravana Kannan
2014-08-07 6:04 ` skannan
2014-08-07 6:04 ` skannan at codeaurora.org
2014-10-16 8:53 ` Viresh Kumar
2014-10-16 8:53 ` Viresh Kumar
2014-10-16 8:53 ` Viresh Kumar
2014-10-23 21:41 ` Saravana Kannan
2014-10-23 21:41 ` Saravana Kannan
2014-10-23 21:41 ` Saravana Kannan
2014-07-16 22:02 ` [PATCH] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend Rafael J. Wysocki
2014-07-16 22:02 ` Rafael J. Wysocki
2014-07-16 22:35 ` Saravana Kannan
2014-07-16 22:35 ` Saravana Kannan
2014-07-24 3:02 ` Saravana Kannan
2014-07-24 3:02 ` Saravana Kannan
2014-07-24 5:04 ` Viresh Kumar
2014-07-24 5:04 ` Viresh Kumar
2014-07-24 5:04 ` Viresh Kumar
2014-07-24 9:12 ` skannan
2014-07-24 9:12 ` skannan at codeaurora.org
2014-07-24 9:12 ` skannan
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