| Message ID | 1491716716-22222-1-git-send-email-yu.c.chen@intel.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Sun, Apr 9, 2017 at 7:45 AM, Chen Yu <yu.c.chen@intel.com> wrote: > There is a report that after > commit 27622b061eb4 ("cpufreq: Convert to hotplug state machine"), > the normal CPU offline/online cycle failed on some platforms. > According to the ftrace result, this problem was triggered on > platforms using acpi-freq as the default cpufreq driver, > and due to the lack of some ACPI freq method(_PCT eg), the > cpufreq_online failed and returned a negative value, thus the CPU > hotplug statemachine rollbacked the CPU online process. Actually > from the user's perspective the failure of cpufreq_online should > not prevent that CPU from being brought up, although cpufreq might > not work on that CPU. BTW, during system bootup the cpufreq_online > is not invoked via cpuhotplug statemachine but by the cpufreq device > creation process, thus the APs can be brought up although cpufreq_online > failed in that stage. > > This patch ignores the return value of cpufreq_online/offline and > let the cpufreq framework to deal with the failure that, cpufreq_online() > will do a proper rollback in that case. And if the _PCT is missing, > the acpi cpufreq driver will print a warning if the corresponding > debug options have been enabled. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=194581 > Fixes: 27622b061eb4 ("cpufreq: Convert to hotplug state machine") > Reported-and-tested-by: Tomasz Maciej Nowak <tmn505@gmail.com> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > Cc: Len Brown <lenb@kernel.org> > Cc: linux-pm@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: Stable <stable@vger.kernel.org> # 4.9+ > Signed-off-by: Chen Yu <yu.c.chen@intel.com> > --- > v2: > - According to Rafael and Sebastian's suggestion, remove > the error log in cpuhp_cpufreq_online/offline, and let > the cpufreq_online and cpufreq_offline to print the warning > and do the necessary rollback if they failed. > --- > drivers/cpufreq/cpufreq.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index bc96d42..0e3f649 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -2398,6 +2398,20 @@ EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); > *********************************************************************/ > static enum cpuhp_state hp_online; > > +static int cpuhp_cpufreq_online(unsigned int cpu) > +{ > + cpufreq_online(cpu); > + > + return 0; > +} > + > +static int cpuhp_cpufreq_offline(unsigned int cpu) > +{ > + cpufreq_offline(cpu); > + > + return 0; > +} > + > /** > * cpufreq_register_driver - register a CPU Frequency driver > * @driver_data: A struct cpufreq_driver containing the values# > @@ -2460,8 +2474,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) > } > > ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online", > - cpufreq_online, > - cpufreq_offline); > + cpuhp_cpufreq_online, > + cpuhp_cpufreq_offline); > if (ret < 0) > goto err_if_unreg; > hp_online = ret; > -- > 2.7.4 That's straightforward enough. Concerns, worries, better ideas? Thanks, Rafael
On 09-04-17, 13:45, Chen Yu wrote: > There is a report that after > commit 27622b061eb4 ("cpufreq: Convert to hotplug state machine"), > the normal CPU offline/online cycle failed on some platforms. > According to the ftrace result, this problem was triggered on > platforms using acpi-freq as the default cpufreq driver, > and due to the lack of some ACPI freq method(_PCT eg), the > cpufreq_online failed and returned a negative value, thus the CPU > hotplug statemachine rollbacked the CPU online process. Actually > from the user's perspective the failure of cpufreq_online should > not prevent that CPU from being brought up, although cpufreq might > not work on that CPU. BTW, during system bootup the cpufreq_online > is not invoked via cpuhotplug statemachine but by the cpufreq device > creation process, thus the APs can be brought up although cpufreq_online > failed in that stage. > > This patch ignores the return value of cpufreq_online/offline and > let the cpufreq framework to deal with the failure that, cpufreq_online() > will do a proper rollback in that case. And if the _PCT is missing, > the acpi cpufreq driver will print a warning if the corresponding > debug options have been enabled. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=194581 > Fixes: 27622b061eb4 ("cpufreq: Convert to hotplug state machine") > Reported-and-tested-by: Tomasz Maciej Nowak <tmn505@gmail.com> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > Cc: Len Brown <lenb@kernel.org> > Cc: linux-pm@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: Stable <stable@vger.kernel.org> # 4.9+ > Signed-off-by: Chen Yu <yu.c.chen@intel.com> > --- > v2: > - According to Rafael and Sebastian's suggestion, remove > the error log in cpuhp_cpufreq_online/offline, and let > the cpufreq_online and cpufreq_offline to print the warning > and do the necessary rollback if they failed. > --- > drivers/cpufreq/cpufreq.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index bc96d42..0e3f649 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -2398,6 +2398,20 @@ EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); > *********************************************************************/ > static enum cpuhp_state hp_online; > > +static int cpuhp_cpufreq_online(unsigned int cpu) > +{ > + cpufreq_online(cpu); > + > + return 0; > +} > + > +static int cpuhp_cpufreq_offline(unsigned int cpu) > +{ > + cpufreq_offline(cpu); > + > + return 0; > +} > + > /** > * cpufreq_register_driver - register a CPU Frequency driver > * @driver_data: A struct cpufreq_driver containing the values# > @@ -2460,8 +2474,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) > } > > ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online", > - cpufreq_online, > - cpufreq_offline); > + cpuhp_cpufreq_online, > + cpuhp_cpufreq_offline); > if (ret < 0) > goto err_if_unreg; > hp_online = ret; Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index bc96d42..0e3f649 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2398,6 +2398,20 @@ EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); *********************************************************************/ static enum cpuhp_state hp_online; +static int cpuhp_cpufreq_online(unsigned int cpu) +{ + cpufreq_online(cpu); + + return 0; +} + +static int cpuhp_cpufreq_offline(unsigned int cpu) +{ + cpufreq_offline(cpu); + + return 0; +} + /** * cpufreq_register_driver - register a CPU Frequency driver * @driver_data: A struct cpufreq_driver containing the values# @@ -2460,8 +2474,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) } ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online", - cpufreq_online, - cpufreq_offline); + cpuhp_cpufreq_online, + cpuhp_cpufreq_offline); if (ret < 0) goto err_if_unreg; hp_online = ret;
There is a report that after commit 27622b061eb4 ("cpufreq: Convert to hotplug state machine"), the normal CPU offline/online cycle failed on some platforms. According to the ftrace result, this problem was triggered on platforms using acpi-freq as the default cpufreq driver, and due to the lack of some ACPI freq method(_PCT eg), the cpufreq_online failed and returned a negative value, thus the CPU hotplug statemachine rollbacked the CPU online process. Actually from the user's perspective the failure of cpufreq_online should not prevent that CPU from being brought up, although cpufreq might not work on that CPU. BTW, during system bootup the cpufreq_online is not invoked via cpuhotplug statemachine but by the cpufreq device creation process, thus the APs can be brought up although cpufreq_online failed in that stage. This patch ignores the return value of cpufreq_online/offline and let the cpufreq framework to deal with the failure that, cpufreq_online() will do a proper rollback in that case. And if the _PCT is missing, the acpi cpufreq driver will print a warning if the corresponding debug options have been enabled. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=194581 Fixes: 27622b061eb4 ("cpufreq: Convert to hotplug state machine") Reported-and-tested-by: Tomasz Maciej Nowak <tmn505@gmail.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Len Brown <lenb@kernel.org> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Stable <stable@vger.kernel.org> # 4.9+ Signed-off-by: Chen Yu <yu.c.chen@intel.com> --- v2: - According to Rafael and Sebastian's suggestion, remove the error log in cpuhp_cpufreq_online/offline, and let the cpufreq_online and cpufreq_offline to print the warning and do the necessary rollback if they failed. --- drivers/cpufreq/cpufreq.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-)