Messages in this thread | | | Date | Tue, 11 Nov 2014 09:10:13 +0530 | Subject | Re: [PATCH 3/5] cpufreq, dbs_data->usage count must be atomic | From | Viresh Kumar <> |
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On 5 November 2014 20:23, Prarit Bhargava <prarit@redhat.com> wrote: > The usage_count value can be modified from several cpus concurrently if > !CPUFREQ_HAVE_GOVERNOR_PER_POLICY. This leads to a variety of panics in > which the usage_count is negative or exceeds the number of cpus in the > system. It must be switched to atomic_t and protected with a mutex to make sure > that future read/writes obtain the correct data.
I think it would be best to serialize calls to ->governor() with some locking in place instead of adding per-variable locks. There can be other points of contention as well.
I have done something similar in the solution I tried. Can pick some of those patches.
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