Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH V4 2/4] cpufreq: intel_pstate: Migrate to ->offline() instead of ->stop_cpu() | Date | Wed, 23 Jun 2021 17:13:00 +0200 |
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On Wednesday, June 23, 2021 6:24:40 AM CEST Viresh Kumar 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 offline() callbacks instead of stop_cpu(). > > Cc: Dirk Brandewie <dirk.brandewie@gmail.com> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpufreq/intel_pstate.c | 10 ++-------- > 1 file changed, 2 insertions(+), 8 deletions(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 0e69dffd5a76..b4c0ff7f5b71 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);
As mentioned already in
https://lore.kernel.org/linux-pm/CAJZ5v0g2tCZptcqh+c55YYiO7rDHmZivMLsmpq_7005zNPN1xg@mail.gmail.com/
this isn't particularly clean, because intel_pstate_cpu_offline() is also used in the passive mode where the above call is not needed.
I would make a change like in the patch below instead.
> + > if (cpu->suspended) > return 0;
--- From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Subject: [PATCH] cpufreq: intel_pstate: Combine ->stop_cpu() and ->offline()
Combine the ->stop_cpu() and ->offline() callback routines for the active mode of intel_pstate so as to avoid setting the ->stop_cpu callback pointer which is going to be dropped from the framework.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> --- drivers/cpufreq/intel_pstate.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c =================================================================== --- linux-pm.orig/drivers/cpufreq/intel_pstate.c +++ linux-pm/drivers/cpufreq/intel_pstate.c @@ -2577,11 +2577,13 @@ static int intel_pstate_cpu_online(struc return 0; } -static void intel_pstate_stop_cpu(struct cpufreq_policy *policy) +static int intel_pstate_stop_cpu(struct cpufreq_policy *policy) { pr_debug("CPU %d stopping\n", policy->cpu); intel_pstate_clear_update_util_hook(policy->cpu); + + return intel_pstate_cpu_offline(policy); } static int intel_pstate_cpu_exit(struct cpufreq_policy *policy) @@ -2654,8 +2656,7 @@ static struct cpufreq_driver intel_pstat .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, + .offline = intel_pstate_stop_cpu, .online = intel_pstate_cpu_online, .update_limits = intel_pstate_update_limits, .name = "intel_pstate",
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