| Message ID | 20191021132818.23787-1-sudeep.holla@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | cpufreq: Move cancelling of policy update work just after removing notifiers | expand |
On 21-10-19, 14:28, Sudeep Holla wrote: > Commit 099967699ad9 ("cpufreq: Cancel policy update work scheduled before freeing") > added cancel_work_sync(policy->update) after the frequency QoS were > removed. We can cancel the work just after taking the last CPU in the > policy offline and unregistering the notifiers as policy->update cannot > be scheduled from anywhere at this point. > > However, due to other bugs, doing so still triggered the race between > freeing of policy and scheduled policy update work. Now that all those > issues are resolved, we can move this cancelling of any scheduled policy > update work just after removing min/max notifiers. > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > --- > drivers/cpufreq/cpufreq.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > Hi Rafael, > > Based on Viresh's suggestion, I am posting a patch to move this > cancel_work_sync earlier though it's not a must have change. For me it is :) > I will leave it up to your preference. > > Regards, > Sudeep > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 829a3764df1b..48a224a6b178 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -1268,6 +1268,9 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) > freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN, > &policy->nb_min); > > + /* Cancel any pending policy->update work before freeing the policy. */ > + cancel_work_sync(&policy->update); > + > if (policy->max_freq_req) { > /* > * CPUFREQ_CREATE_POLICY notification is sent only after > @@ -1279,8 +1282,6 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) > } > > freq_qos_remove_request(policy->min_freq_req); > - /* Cancel any pending policy->update work before freeing the policy. */ > - cancel_work_sync(&policy->update); > kfree(policy->min_freq_req); > > cpufreq_policy_put_kobj(policy); Thanks for doing this. Acked-by: Viresh Kumar <viresh.kumar@linaro.org> -- viresh
On Tue, Oct 22, 2019 at 4:25 AM Viresh Kumar <viresh.kumar@linaro.org> wrote: > > On 21-10-19, 14:28, Sudeep Holla wrote: > > Commit 099967699ad9 ("cpufreq: Cancel policy update work scheduled before freeing") > > added cancel_work_sync(policy->update) after the frequency QoS were > > removed. We can cancel the work just after taking the last CPU in the > > policy offline and unregistering the notifiers as policy->update cannot > > be scheduled from anywhere at this point. > > > > However, due to other bugs, doing so still triggered the race between > > freeing of policy and scheduled policy update work. Now that all those > > issues are resolved, we can move this cancelling of any scheduled policy > > update work just after removing min/max notifiers. > > > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > --- > > drivers/cpufreq/cpufreq.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > Hi Rafael, > > > > Based on Viresh's suggestion, I am posting a patch to move this > > cancel_work_sync earlier though it's not a must have change. > > For me it is :) > > > I will leave it up to your preference. > > > > Regards, > > Sudeep > > > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > > index 829a3764df1b..48a224a6b178 100644 > > --- a/drivers/cpufreq/cpufreq.c > > +++ b/drivers/cpufreq/cpufreq.c > > @@ -1268,6 +1268,9 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) > > freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN, > > &policy->nb_min); > > > > + /* Cancel any pending policy->update work before freeing the policy. */ > > + cancel_work_sync(&policy->update); > > + > > if (policy->max_freq_req) { > > /* > > * CPUFREQ_CREATE_POLICY notification is sent only after > > @@ -1279,8 +1282,6 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) > > } > > > > freq_qos_remove_request(policy->min_freq_req); > > - /* Cancel any pending policy->update work before freeing the policy. */ > > - cancel_work_sync(&policy->update); > > kfree(policy->min_freq_req); > > > > cpufreq_policy_put_kobj(policy); > > Thanks for doing this. > > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Folded into the previous patch and applied. Please double check the result in the current linux-next branch in my tree.
On 22-10-19, 11:46, Rafael J. Wysocki wrote: > On Tue, Oct 22, 2019 at 4:25 AM Viresh Kumar <viresh.kumar@linaro.org> wrote: > > > > On 21-10-19, 14:28, Sudeep Holla wrote: > > > Commit 099967699ad9 ("cpufreq: Cancel policy update work scheduled before freeing") > > > added cancel_work_sync(policy->update) after the frequency QoS were > > > removed. We can cancel the work just after taking the last CPU in the > > > policy offline and unregistering the notifiers as policy->update cannot > > > be scheduled from anywhere at this point. > > > > > > However, due to other bugs, doing so still triggered the race between > > > freeing of policy and scheduled policy update work. Now that all those > > > issues are resolved, we can move this cancelling of any scheduled policy > > > update work just after removing min/max notifiers. > > > > > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > > --- > > > drivers/cpufreq/cpufreq.c | 5 +++-- > > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > > > Hi Rafael, > > > > > > Based on Viresh's suggestion, I am posting a patch to move this > > > cancel_work_sync earlier though it's not a must have change. > > > > For me it is :) > > > > > I will leave it up to your preference. > > > > > > Regards, > > > Sudeep > > > > > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > > > index 829a3764df1b..48a224a6b178 100644 > > > --- a/drivers/cpufreq/cpufreq.c > > > +++ b/drivers/cpufreq/cpufreq.c > > > @@ -1268,6 +1268,9 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) > > > freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN, > > > &policy->nb_min); > > > > > > + /* Cancel any pending policy->update work before freeing the policy. */ > > > + cancel_work_sync(&policy->update); > > > + > > > if (policy->max_freq_req) { > > > /* > > > * CPUFREQ_CREATE_POLICY notification is sent only after > > > @@ -1279,8 +1282,6 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) > > > } > > > > > > freq_qos_remove_request(policy->min_freq_req); > > > - /* Cancel any pending policy->update work before freeing the policy. */ > > > - cancel_work_sync(&policy->update); > > > kfree(policy->min_freq_req); > > > > > > cpufreq_policy_put_kobj(policy); > > > > Thanks for doing this. > > > > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> > > Folded into the previous patch and applied. > > Please double check the result in the current linux-next branch in my tree. I would have kept the blank line after cancel_work_sync() which isn't there anymore. -- viresh
On Tue, Oct 22, 2019 at 12:07 PM Viresh Kumar <viresh.kumar@linaro.org> wrote: > > On 22-10-19, 11:46, Rafael J. Wysocki wrote: > > On Tue, Oct 22, 2019 at 4:25 AM Viresh Kumar <viresh.kumar@linaro.org> wrote: > > > > > > On 21-10-19, 14:28, Sudeep Holla wrote: > > > > Commit 099967699ad9 ("cpufreq: Cancel policy update work scheduled before freeing") > > > > added cancel_work_sync(policy->update) after the frequency QoS were > > > > removed. We can cancel the work just after taking the last CPU in the > > > > policy offline and unregistering the notifiers as policy->update cannot > > > > be scheduled from anywhere at this point. > > > > > > > > However, due to other bugs, doing so still triggered the race between > > > > freeing of policy and scheduled policy update work. Now that all those > > > > issues are resolved, we can move this cancelling of any scheduled policy > > > > update work just after removing min/max notifiers. > > > > > > > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > > > --- > > > > drivers/cpufreq/cpufreq.c | 5 +++-- > > > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > > > > > Hi Rafael, > > > > > > > > Based on Viresh's suggestion, I am posting a patch to move this > > > > cancel_work_sync earlier though it's not a must have change. > > > > > > For me it is :) > > > > > > > I will leave it up to your preference. > > > > > > > > Regards, > > > > Sudeep > > > > > > > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > > > > index 829a3764df1b..48a224a6b178 100644 > > > > --- a/drivers/cpufreq/cpufreq.c > > > > +++ b/drivers/cpufreq/cpufreq.c > > > > @@ -1268,6 +1268,9 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) > > > > freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN, > > > > &policy->nb_min); > > > > > > > > + /* Cancel any pending policy->update work before freeing the policy. */ > > > > + cancel_work_sync(&policy->update); > > > > + > > > > if (policy->max_freq_req) { > > > > /* > > > > * CPUFREQ_CREATE_POLICY notification is sent only after > > > > @@ -1279,8 +1282,6 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) > > > > } > > > > > > > > freq_qos_remove_request(policy->min_freq_req); > > > > - /* Cancel any pending policy->update work before freeing the policy. */ > > > > - cancel_work_sync(&policy->update); > > > > kfree(policy->min_freq_req); > > > > > > > > cpufreq_policy_put_kobj(policy); > > > > > > Thanks for doing this. > > > > > > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> > > > > Folded into the previous patch and applied. > > > > Please double check the result in the current linux-next branch in my tree. > > I would have kept the blank line after cancel_work_sync() which isn't > there anymore. OK, it looks better with the extra blank line, so updated. Thanks!
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 829a3764df1b..48a224a6b178 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1268,6 +1268,9 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN, &policy->nb_min); + /* Cancel any pending policy->update work before freeing the policy. */ + cancel_work_sync(&policy->update); + if (policy->max_freq_req) { /* * CPUFREQ_CREATE_POLICY notification is sent only after @@ -1279,8 +1282,6 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) } freq_qos_remove_request(policy->min_freq_req); - /* Cancel any pending policy->update work before freeing the policy. */ - cancel_work_sync(&policy->update); kfree(policy->min_freq_req); cpufreq_policy_put_kobj(policy);
Commit 099967699ad9 ("cpufreq: Cancel policy update work scheduled before freeing") added cancel_work_sync(policy->update) after the frequency QoS were removed. We can cancel the work just after taking the last CPU in the policy offline and unregistering the notifiers as policy->update cannot be scheduled from anywhere at this point. However, due to other bugs, doing so still triggered the race between freeing of policy and scheduled policy update work. Now that all those issues are resolved, we can move this cancelling of any scheduled policy update work just after removing min/max notifiers. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> --- drivers/cpufreq/cpufreq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) Hi Rafael, Based on Viresh's suggestion, I am posting a patch to move this cancel_work_sync earlier though it's not a must have change. I will leave it up to your preference. Regards, Sudeep -- 2.17.1