Re: [PATCH linux-next v8] cpufreq: convert the cpufreq_driver to use the rcu

Viresh Kumar
2013-04-04T16:27:23Z

On 4 April 2013 20:23, Nathan Zimmer <nzimmer@sgi.com> wrote:
> We eventually would like to remove the rwlock cpufreq_driver_lock or convert
> it back to a spinlock and protect the read sections with RCU. The first step in
> that is moving the cpufreq_driver to use the rcu.
> I don't see an easy wasy to protect the cpufreq_cpu_data structure with the
> RCU, so I am leaving it with the rwlock for now since under certain configs
> __cpufreq_cpu_get is hot spot with 256+ cores.
>
> v5: Go a different way and split up the lock and use the rcu
> v6: use bools instead of checking function pointers
> covert the cpufreq_data_lock to a rwlock
> v7: Rebase to use the already accepted half
> v8: Correct have_governor_per_policy
> Reviewed location of rcu_read_(un)lock in several spots

Sorry for long delay or too many versions of this patch :)

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>