Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Fri, 18 Jun 2021 14:00:54 +0200 | Subject | Re: [PATCH V3 2/3] cpufreq: intel_pstate: Migrate away from ->stop_cpu() callback |
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On Fri, Jun 18, 2021 at 5:22 AM Viresh Kumar <viresh.kumar@linaro.org> wrote: > > commit 367dc4aa932b ("cpufreq: Add stop CPU callback to cpufreq_driver > interface") added the stop_cpu() callback to allow the drivers to do > clean up before the CPU is completely down and its state can't be > modified. > > At that time the CPU hotplug framework used to call the cpufreq core's > registered notifier for different events like CPU_DOWN_PREPARE and > CPU_POST_DEAD. The stop_cpu() callback was called during the > CPU_DOWN_PREPARE event. > > This is no longer the case, cpuhp_cpufreq_offline() is called only once > by the CPU hotplug core now and we don't really need to separately > call stop_cpu() for cpufreq drivers. > > Migrate to using the exit() and offline() callbacks instead of > stop_cpu(). > > We need to clear util hook from both the callbacks, exit() and > offline(), since it is possible that only exit() gets called sometimes > (specially on errors) or both get called at other times. > intel_pstate_clear_update_util_hook() anyway have enough protection in > place if it gets called a second time and will return early then. > > Cc: Dirk Brandewie <dirk.brandewie@gmail.com> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > V2->V3: > - Update intel_pstate_cpu_offline() as well. > - Improved commit log. > > drivers/cpufreq/intel_pstate.c | 12 ++++-------- > 1 file changed, 4 insertions(+), 8 deletions(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 0e69dffd5a76..8f8a2d9d7daa 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -2335,6 +2335,8 @@ static int intel_pstate_cpu_offline(struct cpufreq_policy *policy) > > pr_debug("CPU %d going offline\n", cpu->cpu); > > + intel_pstate_clear_update_util_hook(policy->cpu); > + > if (cpu->suspended) > return 0; > > @@ -2374,17 +2376,12 @@ static int intel_pstate_cpu_online(struct cpufreq_policy *policy) > return 0; > } > > -static void intel_pstate_stop_cpu(struct cpufreq_policy *policy) > -{ > - pr_debug("CPU %d stopping\n", policy->cpu); > - > - intel_pstate_clear_update_util_hook(policy->cpu); > -} > - > static int intel_pstate_cpu_exit(struct cpufreq_policy *policy) > { > pr_debug("CPU %d exiting\n", policy->cpu); > > + intel_pstate_clear_update_util_hook(policy->cpu);
This change is not needed now, because ->offline always runs before ->exit if present.
> + > policy->fast_switch_possible = false; > > return 0; > @@ -2451,7 +2448,6 @@ static struct cpufreq_driver intel_pstate = { > .resume = intel_pstate_resume, > .init = intel_pstate_cpu_init, > .exit = intel_pstate_cpu_exit, > - .stop_cpu = intel_pstate_stop_cpu, > .offline = intel_pstate_cpu_offline, > .online = intel_pstate_cpu_online, > .update_limits = intel_pstate_update_limits, > -- > 2.31.1.272.g89b43f80a514 >
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