From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>, Juri Lelli <juri.lelli@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
linux@arm.linux.org.uk,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Russell King <rmk+kernel@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Morten Rasmussen <morten.rasmussen@arm.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>
Subject: Re: [PATCH v2 01/10] drivers base/arch_topology: free cpumask cpus_to_visit
Date: Fri, 7 Jul 2017 16:50:43 +0100 [thread overview]
Message-ID: <0133bcf5-0037-7b31-94d9-98fa241355a1@arm.com> (raw)
In-Reply-To: <20170706111506.GB1523@vireshk-i7>
On 06/07/17 12:15, Viresh Kumar wrote:
> On 06-07-17, 11:59, Juri Lelli wrote:
>> On 06/07/17 15:52, Viresh Kumar wrote:
[...]
>>
>> If that's the case I'm wondering however if we need explicit
>> synchronization though. Otherwise both threads can read the mask as
>> full, clear only their bits and not schedule the workfn?
>
> Maybe not as the policies are created one by one only, not concurrently.
>
>> But, can the policies be concurrently initialized? Or is the
>> initialization process serialized or the different domains?
>
> There can be complex cases here. For example consider this.
>
> Only the little CPUs are brought online at boot. Their policy is set and they
> are cleared from the cpus_to_visit mask. Now we try to bring any big CPU online
> and at the same time try changing min/max from sysfs for the LITTLE CPU policy.
>
> The notifier may get called concurrently here I believe and cause the problem I
> mentioned earlier.
>
I chatted with Juri and your proposed fix to do the unregister before
the free makes sense to us. Thanks for spotting this! I will change in
the next version.
next prev parent reply other threads:[~2017-07-07 15:50 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-06 9:49 [PATCH v2 00/10] arm, arm64: frequency- and cpu-invariant accounting support for task scheduler Dietmar Eggemann
2017-07-06 9:49 ` [PATCH v2 01/10] drivers base/arch_topology: free cpumask cpus_to_visit Dietmar Eggemann
2017-07-06 10:22 ` Viresh Kumar
2017-07-06 10:59 ` Juri Lelli
2017-07-06 11:15 ` Viresh Kumar
2017-07-07 15:50 ` Dietmar Eggemann [this message]
2017-07-06 9:49 ` [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support Dietmar Eggemann
2017-07-06 10:40 ` Viresh Kumar
2017-07-06 22:38 ` Rafael J. Wysocki
2017-07-07 16:01 ` Dietmar Eggemann
2017-07-07 16:18 ` Rafael J. Wysocki
2017-07-07 17:06 ` Dietmar Eggemann
2017-07-08 12:09 ` Rafael J. Wysocki
2017-07-10 6:54 ` Viresh Kumar
2017-07-10 12:46 ` Rafael J. Wysocki
2017-07-11 6:39 ` Viresh Kumar
2017-07-11 15:21 ` Dietmar Eggemann
2017-07-13 12:40 ` Sudeep Holla
2017-07-13 13:08 ` Dietmar Eggemann
2017-07-13 14:06 ` Sudeep Holla
2017-07-10 9:30 ` Peter Zijlstra
2017-07-10 9:42 ` Viresh Kumar
2017-07-10 10:31 ` Dietmar Eggemann
2017-07-10 12:02 ` Dietmar Eggemann
2017-07-11 6:01 ` Viresh Kumar
2017-07-11 15:06 ` Dietmar Eggemann
2017-07-11 14:59 ` Rafael J. Wysocki
2017-07-11 15:12 ` Dietmar Eggemann
2017-07-12 4:09 ` Viresh Kumar
2017-07-12 8:31 ` Peter Zijlstra
2017-07-12 9:27 ` Viresh Kumar
2017-07-12 11:14 ` Peter Zijlstra
2017-07-12 23:13 ` Rafael J. Wysocki
2017-07-13 7:49 ` Peter Zijlstra
2017-07-13 8:48 ` Viresh Kumar
2017-07-13 11:15 ` Peter Zijlstra
2017-07-13 14:04 ` Sudeep Holla
2017-07-13 14:42 ` Peter Zijlstra
2017-07-13 15:00 ` Sudeep Holla
2017-07-13 12:54 ` Sudeep Holla
2017-07-13 12:49 ` Sudeep Holla
2017-07-10 6:40 ` Viresh Kumar
2017-07-06 9:49 ` [PATCH v2 03/10] drivers base/arch_topology: " Dietmar Eggemann
2017-07-06 10:45 ` Viresh Kumar
2017-07-07 16:51 ` Dietmar Eggemann
2017-07-06 9:49 ` [PATCH v2 04/10] arm: wire cpufreq input data for frequency-invariant accounting up to the arch Dietmar Eggemann
2017-07-06 10:42 ` Viresh Kumar
2017-07-10 15:13 ` Dietmar Eggemann
2017-07-11 6:32 ` Viresh Kumar
2017-07-06 9:49 ` [PATCH v2 05/10] arm: wire frequency-invariant accounting support up to the task scheduler Dietmar Eggemann
2017-07-06 10:46 ` Viresh Kumar
2017-07-06 9:49 ` [PATCH v2 06/10] arm: wire cpu-invariant " Dietmar Eggemann
2017-07-06 10:47 ` Viresh Kumar
2017-07-06 9:49 ` [PATCH v2 07/10] arm64: wire cpufreq input data for frequency-invariant accounting up to the arch Dietmar Eggemann
2017-07-06 10:48 ` Viresh Kumar
2017-07-06 9:49 ` [PATCH v2 08/10] arm64: wire frequency-invariant accounting support up to the task scheduler Dietmar Eggemann
2017-07-06 10:48 ` Viresh Kumar
2017-07-06 9:49 ` [PATCH v2 09/10] arm64: wire cpu-invariant " Dietmar Eggemann
2017-07-06 10:49 ` Viresh Kumar
2017-07-06 9:49 ` [PATCH v2 10/10] drivers base/arch_topology: inline cpu- and frequency-invariant accounting Dietmar Eggemann
2017-07-06 10:57 ` Viresh Kumar
2017-07-10 15:17 ` Dietmar Eggemann
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