| Message ID | 20230912061057.2516963-2-liaochang1@huawei.com (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
| Series | [1/2] cpufreq: userspace: Use fine-grained mutex in userspace governor | expand |
On 12-09-23, 06:10, Liao Chang wrote: > The userspace governor use the 'cpu' field of cpufreq_policy structure > to track if it is allowed to set the speed of policy. However, there is > a window where the 'cpu' field is equal to the value of nr_cpus_id when > all affected CPUs of policy are offline, which is an illegal value to > get the per-CPU variable. To avoid this issue, this patch uses a > per-policy indicator to track if the policy is managed. > > Signed-off-by: Liao Chang <liaochang1@huawei.com> > --- > drivers/cpufreq/cpufreq_userspace.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c > index 442e31060d62..2c42fee76daa 100644 > --- a/drivers/cpufreq/cpufreq_userspace.c > +++ b/drivers/cpufreq/cpufreq_userspace.c > @@ -15,9 +15,8 @@ > #include <linux/mutex.h> > #include <linux/slab.h> > > -static DEFINE_PER_CPU(unsigned int, cpu_is_managed); > - > struct userspace_policy { > + unsigned int is_managed; > unsigned int setspeed; > struct mutex mutex; > }; > @@ -37,7 +36,7 @@ static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) > pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq); > > mutex_lock(&userspace->mutex); > - if (!per_cpu(cpu_is_managed, policy->cpu)) > + if (!userspace->is_managed) > goto err; > > userspace->setspeed = freq; > @@ -85,7 +84,7 @@ static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy) > pr_debug("started managing cpu %u\n", policy->cpu); > > mutex_lock(&userspace->mutex); > - per_cpu(cpu_is_managed, policy->cpu) = 1; > + userspace->is_managed = 1; > userspace->setspeed = policy->cur; > mutex_unlock(&userspace->mutex); > return 0; > @@ -98,7 +97,7 @@ static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy) > pr_debug("managing cpu %u stopped\n", policy->cpu); > > mutex_lock(&userspace->mutex); > - per_cpu(cpu_is_managed, policy->cpu) = 0; > + userspace->is_managed = 0; > userspace->setspeed = 0; > mutex_unlock(&userspace->mutex); > } Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c index 442e31060d62..2c42fee76daa 100644 --- a/drivers/cpufreq/cpufreq_userspace.c +++ b/drivers/cpufreq/cpufreq_userspace.c @@ -15,9 +15,8 @@ #include <linux/mutex.h> #include <linux/slab.h> -static DEFINE_PER_CPU(unsigned int, cpu_is_managed); - struct userspace_policy { + unsigned int is_managed; unsigned int setspeed; struct mutex mutex; }; @@ -37,7 +36,7 @@ static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq); mutex_lock(&userspace->mutex); - if (!per_cpu(cpu_is_managed, policy->cpu)) + if (!userspace->is_managed) goto err; userspace->setspeed = freq; @@ -85,7 +84,7 @@ static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy) pr_debug("started managing cpu %u\n", policy->cpu); mutex_lock(&userspace->mutex); - per_cpu(cpu_is_managed, policy->cpu) = 1; + userspace->is_managed = 1; userspace->setspeed = policy->cur; mutex_unlock(&userspace->mutex); return 0; @@ -98,7 +97,7 @@ static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy) pr_debug("managing cpu %u stopped\n", policy->cpu); mutex_lock(&userspace->mutex); - per_cpu(cpu_is_managed, policy->cpu) = 0; + userspace->is_managed = 0; userspace->setspeed = 0; mutex_unlock(&userspace->mutex); }
The userspace governor use the 'cpu' field of cpufreq_policy structure to track if it is allowed to set the speed of policy. However, there is a window where the 'cpu' field is equal to the value of nr_cpus_id when all affected CPUs of policy are offline, which is an illegal value to get the per-CPU variable. To avoid this issue, this patch uses a per-policy indicator to track if the policy is managed. Signed-off-by: Liao Chang <liaochang1@huawei.com> --- drivers/cpufreq/cpufreq_userspace.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)