* [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy()
@ 2014-02-25 8:50 Viresh Kumar
2014-02-25 8:50 ` [PATCH 2/3] cpufreq: Initialize policy before making it available for others to use Viresh Kumar
` (3 more replies)
0 siblings, 4 replies; 7+ messages in thread
From: Viresh Kumar @ 2014-02-25 8:50 UTC (permalink / raw)
To: rjw, skannan
Cc: linaro-kernel, cpufreq, linux-pm, linux-kernel, srivatsa.bhat,
Viresh Kumar
We call __find_governor() during addition of first CPU of every policy to find
the last governor used for this CPU before it was hotplugged-out.
After that we call cpufreq_parse_governor() in cpufreq_init_policy() either with
this governor or default governor. And right after that policy->governor is set
to NULL.
So, instead of doing this move the relevant parts to cpufreq_init_policy()
policy only and initialize policy->governor to NULL at the beginning.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
Hi Saravana,
I hope only the first two patches would fix things for you but probably you can
test all three.
@Rafael: We might need to get these in next rc only as these are more or less
fixes.
drivers/cpufreq/cpufreq.c | 34 ++++++++++++++++------------------
1 file changed, 16 insertions(+), 18 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index c755b5f..cc4f244 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -879,18 +879,27 @@ err_out_kobj_put:
static void cpufreq_init_policy(struct cpufreq_policy *policy)
{
+ struct cpufreq_governor *gov = NULL;
struct cpufreq_policy new_policy;
int ret = 0;
memcpy(&new_policy, policy, sizeof(*policy));
+ /* Update governor of new_policy to the governor used before hotplug */
+#ifdef CONFIG_HOTPLUG_CPU
+ gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu));
+#endif
+ if (gov)
+ pr_debug("Restoring governor %s for cpu %d\n",
+ policy->governor->name, policy->cpu);
+ else
+ gov = CPUFREQ_DEFAULT_GOVERNOR;
+
+ new_policy.governor = gov;
+
/* Use the default policy if its valid. */
if (cpufreq_driver->setpolicy)
- cpufreq_parse_governor(policy->governor->name,
- &new_policy.policy, NULL);
-
- /* assure that the starting sequence is run in cpufreq_set_policy */
- policy->governor = NULL;
+ cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
/* set default policy */
ret = cpufreq_set_policy(policy, &new_policy);
@@ -944,11 +953,11 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
unsigned long flags;
read_lock_irqsave(&cpufreq_driver_lock, flags);
-
policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
-
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
+ policy->governor = NULL;
+
return policy;
}
@@ -1036,7 +1045,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
unsigned long flags;
#ifdef CONFIG_HOTPLUG_CPU
struct cpufreq_policy *tpolicy;
- struct cpufreq_governor *gov;
#endif
if (cpu_is_offline(cpu))
@@ -1094,7 +1102,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
else
policy->cpu = cpu;
- policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
cpumask_copy(policy->cpus, cpumask_of(cpu));
init_completion(&policy->kobj_unregister);
@@ -1179,15 +1186,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_START, policy);
-#ifdef CONFIG_HOTPLUG_CPU
- gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
- if (gov) {
- policy->governor = gov;
- pr_debug("Restoring governor %s for cpu %d\n",
- policy->governor->name, cpu);
- }
-#endif
-
if (!frozen) {
ret = cpufreq_add_dev_interface(policy, dev);
if (ret)
--
1.7.12.rc2.18.g61b472e
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/3] cpufreq: Initialize policy before making it available for others to use
2014-02-25 8:50 [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy() Viresh Kumar
@ 2014-02-25 8:50 ` Viresh Kumar
2014-03-01 1:14 ` Rafael J. Wysocki
2014-02-25 8:50 ` [PATCH 3/3] cpufreq: initialize governor for a new policy under policy->rwsem Viresh Kumar
` (2 subsequent siblings)
3 siblings, 1 reply; 7+ messages in thread
From: Viresh Kumar @ 2014-02-25 8:50 UTC (permalink / raw)
To: rjw, skannan
Cc: linaro-kernel, cpufreq, linux-pm, linux-kernel, srivatsa.bhat,
Viresh Kumar
Policy must be fully initialized before it is being made available for use by
others. This patch moves some initialization code before making policy available
for others.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/cpufreq/cpufreq.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index cc4f244..110c0cd 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1116,6 +1116,20 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
goto err_set_policy_cpu;
}
+ /* related cpus should atleast have policy->cpus */
+ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
+
+ /*
+ * affected cpus must always be the one, which are online. We aren't
+ * managing offline cpus here.
+ */
+ cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
+
+ if (!frozen) {
+ policy->user_policy.min = policy->min;
+ policy->user_policy.max = policy->max;
+ }
+
write_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_cpu(j, policy->cpus)
per_cpu(cpufreq_cpu_data, j) = policy;
@@ -1169,20 +1183,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
}
}
- /* related cpus should atleast have policy->cpus */
- cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
-
- /*
- * affected cpus must always be the one, which are online. We aren't
- * managing offline cpus here.
- */
- cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
-
- if (!frozen) {
- policy->user_policy.min = policy->min;
- policy->user_policy.max = policy->max;
- }
-
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_START, policy);
--
1.7.12.rc2.18.g61b472e
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 3/3] cpufreq: initialize governor for a new policy under policy->rwsem
2014-02-25 8:50 [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy() Viresh Kumar
2014-02-25 8:50 ` [PATCH 2/3] cpufreq: Initialize policy before making it available for others to use Viresh Kumar
@ 2014-02-25 8:50 ` Viresh Kumar
2014-03-01 1:00 ` [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy() Rafael J. Wysocki
2014-03-01 1:09 ` Rafael J. Wysocki
3 siblings, 0 replies; 7+ messages in thread
From: Viresh Kumar @ 2014-02-25 8:50 UTC (permalink / raw)
To: rjw, skannan
Cc: linaro-kernel, cpufreq, linux-pm, linux-kernel, srivatsa.bhat,
Viresh Kumar
policy->rwsem is used to lock access to all parts of code modifying struct
cpufreq_policy but wasn't used on a new policy created from __cpufreq_add_dev().
Because of which if we call cpufreq_update_policy() repeatedly on one CPU and do
offline/online of another CPU then we might see these crashes:
Unable to handle kernel NULL pointer dereference at virtual address 00000020
pgd = c0003000
[00000020] *pgd=80000000004003, *pmd=00000000
Internal error: Oops: 206 [#1] PREEMPT SMP ARM
PC is at __cpufreq_governor+0x10/0x1ac
LR is at cpufreq_update_policy+0x114/0x150
---[ end trace f23a8defea6cd706 ]---
Kernel panic - not syncing: Fatal exception
CPU0: stopping
CPU: 0 PID: 7136 Comm: mpdecision Tainted: G D W 3.10.0-gd727407-00074-g979ede8 #396
[<c0afe180>] (notifier_call_chain+0x40/0x68) from [<c02a23ac>] (__blocking_notifier_call_chain+0x40/0x58)
[<c02a23ac>] (__blocking_notifier_call_chain+0x40/0x58) from [<c02a23d8>] (blocking_notifier_call_chain+0x14/0x1c)
[<c02a23d8>] (blocking_notifier_call_chain+0x14/0x1c) from [<c0803c68>] (cpufreq_set_policy+0xd4/0x2b8)
[<c0803c68>] (cpufreq_set_policy+0xd4/0x2b8) from [<c0803e7c>] (cpufreq_init_policy+0x30/0x98)
[<c0803e7c>] (cpufreq_init_policy+0x30/0x98) from [<c0805a18>] (__cpufreq_add_dev.isra.17+0x4dc/0x7a4)
[<c0805a18>] (__cpufreq_add_dev.isra.17+0x4dc/0x7a4) from [<c0805d38>] (cpufreq_cpu_callback+0x58/0x84)
[<c0805d38>] (cpufreq_cpu_callback+0x58/0x84) from [<c0afe180>] (notifier_call_chain+0x40/0x68)
[<c0afe180>] (notifier_call_chain+0x40/0x68) from [<c02812dc>] (__cpu_notify+0x28/0x44)
[<c02812dc>] (__cpu_notify+0x28/0x44) from [<c0aeed90>] (_cpu_up+0xf4/0x1dc)
[<c0aeed90>] (_cpu_up+0xf4/0x1dc) from [<c0aeeed4>] (cpu_up+0x5c/0x78)
[<c0aeeed4>] (cpu_up+0x5c/0x78) from [<c0aec808>] (store_online+0x44/0x74)
[<c0aec808>] (store_online+0x44/0x74) from [<c03a40f4>] (sysfs_write_file+0x108/0x14c)
[<c03a40f4>] (sysfs_write_file+0x108/0x14c) from [<c03517d4>] (vfs_write+0xd0/0x180)
[<c03517d4>] (vfs_write+0xd0/0x180) from [<c0351ca8>] (SyS_write+0x38/0x68)
[<c0351ca8>] (SyS_write+0x38/0x68) from [<c0205de0>] (ret_fast_syscall+0x0/0x30)
Fix these by taking locks at appropriate places in __cpufreq_add_dev() as well.
Reported-by: Saravana Kannan <skannan@codeaurora.org>
Suggested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/cpufreq/cpufreq.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 110c0cd..513d1d4 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1130,6 +1130,7 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
policy->user_policy.max = policy->max;
}
+ down_write(&policy->rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_cpu(j, policy->cpus)
per_cpu(cpufreq_cpu_data, j) = policy;
@@ -1204,6 +1205,7 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
policy->user_policy.policy = policy->policy;
policy->user_policy.governor = policy->governor;
}
+ up_write(&policy->rwsem);
kobject_uevent(&policy->kobj, KOBJ_ADD);
up_read(&cpufreq_rwsem);
--
1.7.12.rc2.18.g61b472e
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy()
2014-02-25 8:50 [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy() Viresh Kumar
2014-02-25 8:50 ` [PATCH 2/3] cpufreq: Initialize policy before making it available for others to use Viresh Kumar
2014-02-25 8:50 ` [PATCH 3/3] cpufreq: initialize governor for a new policy under policy->rwsem Viresh Kumar
@ 2014-03-01 1:00 ` Rafael J. Wysocki
2014-03-01 1:09 ` Rafael J. Wysocki
3 siblings, 0 replies; 7+ messages in thread
From: Rafael J. Wysocki @ 2014-03-01 1:00 UTC (permalink / raw)
To: Viresh Kumar
Cc: skannan, linaro-kernel, cpufreq, linux-pm, linux-kernel, srivatsa.bhat
On Tuesday, February 25, 2014 02:20:09 PM Viresh Kumar wrote:
> We call __find_governor() during addition of first CPU of every policy to find
> the last governor used for this CPU before it was hotplugged-out.
>
> After that we call cpufreq_parse_governor() in cpufreq_init_policy() either with
> this governor or default governor. And right after that policy->governor is set
> to NULL.
This is a problem, right? So care to write *why* it is a problem here?
> So, instead of doing this move the relevant parts to cpufreq_init_policy()
> policy only and initialize policy->governor to NULL at the beginning.
And this change is supposed to fix that problem, right? You're not moving
stuff around just for the fun of it?
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> ---
>
> Hi Saravana,
>
> I hope only the first two patches would fix things for you but probably you can
> test all three.
>
> @Rafael: We might need to get these in next rc only as these are more or less
> fixes.
>
> drivers/cpufreq/cpufreq.c | 34 ++++++++++++++++------------------
> 1 file changed, 16 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index c755b5f..cc4f244 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -879,18 +879,27 @@ err_out_kobj_put:
>
> static void cpufreq_init_policy(struct cpufreq_policy *policy)
> {
> + struct cpufreq_governor *gov = NULL;
> struct cpufreq_policy new_policy;
> int ret = 0;
>
> memcpy(&new_policy, policy, sizeof(*policy));
>
> + /* Update governor of new_policy to the governor used before hotplug */
> +#ifdef CONFIG_HOTPLUG_CPU
> + gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu));
> +#endif
> + if (gov)
> + pr_debug("Restoring governor %s for cpu %d\n",
> + policy->governor->name, policy->cpu);
> + else
> + gov = CPUFREQ_DEFAULT_GOVERNOR;
> +
> + new_policy.governor = gov;
> +
> /* Use the default policy if its valid. */
> if (cpufreq_driver->setpolicy)
> - cpufreq_parse_governor(policy->governor->name,
> - &new_policy.policy, NULL);
> -
> - /* assure that the starting sequence is run in cpufreq_set_policy */
> - policy->governor = NULL;
> + cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
>
> /* set default policy */
> ret = cpufreq_set_policy(policy, &new_policy);
> @@ -944,11 +953,11 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
> unsigned long flags;
>
> read_lock_irqsave(&cpufreq_driver_lock, flags);
> -
> policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
> -
> read_unlock_irqrestore(&cpufreq_driver_lock, flags);
>
> + policy->governor = NULL;
> +
> return policy;
> }
>
> @@ -1036,7 +1045,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
> unsigned long flags;
> #ifdef CONFIG_HOTPLUG_CPU
> struct cpufreq_policy *tpolicy;
> - struct cpufreq_governor *gov;
> #endif
>
> if (cpu_is_offline(cpu))
> @@ -1094,7 +1102,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
> else
> policy->cpu = cpu;
>
> - policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
> cpumask_copy(policy->cpus, cpumask_of(cpu));
>
> init_completion(&policy->kobj_unregister);
> @@ -1179,15 +1186,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
> blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
> CPUFREQ_START, policy);
>
> -#ifdef CONFIG_HOTPLUG_CPU
> - gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
> - if (gov) {
> - policy->governor = gov;
> - pr_debug("Restoring governor %s for cpu %d\n",
> - policy->governor->name, cpu);
> - }
> -#endif
> -
> if (!frozen) {
> ret = cpufreq_add_dev_interface(policy, dev);
> if (ret)
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy()
2014-02-25 8:50 [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy() Viresh Kumar
` (2 preceding siblings ...)
2014-03-01 1:00 ` [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy() Rafael J. Wysocki
@ 2014-03-01 1:09 ` Rafael J. Wysocki
2014-03-04 3:43 ` Viresh Kumar
3 siblings, 1 reply; 7+ messages in thread
From: Rafael J. Wysocki @ 2014-03-01 1:09 UTC (permalink / raw)
To: Viresh Kumar
Cc: skannan, linaro-kernel, cpufreq, linux-pm, linux-kernel, srivatsa.bhat
On Tuesday, February 25, 2014 02:20:09 PM Viresh Kumar wrote:
> We call __find_governor() during addition of first CPU of every policy to find
> the last governor used for this CPU before it was hotplugged-out.
>
> After that we call cpufreq_parse_governor() in cpufreq_init_policy() either with
> this governor or default governor. And right after that policy->governor is set
> to NULL.
>
> So, instead of doing this move the relevant parts to cpufreq_init_policy()
> policy only and initialize policy->governor to NULL at the beginning.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>
> Hi Saravana,
>
> I hope only the first two patches would fix things for you but probably you can
> test all three.
>
> @Rafael: We might need to get these in next rc only as these are more or less
> fixes.
>
> drivers/cpufreq/cpufreq.c | 34 ++++++++++++++++------------------
> 1 file changed, 16 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index c755b5f..cc4f244 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -879,18 +879,27 @@ err_out_kobj_put:
>
> static void cpufreq_init_policy(struct cpufreq_policy *policy)
> {
> + struct cpufreq_governor *gov = NULL;
> struct cpufreq_policy new_policy;
> int ret = 0;
>
> memcpy(&new_policy, policy, sizeof(*policy));
>
And while I'm at it, can we *please* avoid adding new #ifdef blocks into
function bodies?
Please introduce a wrapper around __find_governor() returning NULL for
CONFIG_HOTPLUG_CPU unset.
> + /* Update governor of new_policy to the governor used before hotplug */
> +#ifdef CONFIG_HOTPLUG_CPU
> + gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu));
> +#endif
> + if (gov)
> + pr_debug("Restoring governor %s for cpu %d\n",
> + policy->governor->name, policy->cpu);
> + else
> + gov = CPUFREQ_DEFAULT_GOVERNOR;
> +
> + new_policy.governor = gov;
> +
> /* Use the default policy if its valid. */
> if (cpufreq_driver->setpolicy)
> - cpufreq_parse_governor(policy->governor->name,
> - &new_policy.policy, NULL);
> -
> - /* assure that the starting sequence is run in cpufreq_set_policy */
> - policy->governor = NULL;
> + cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
>
> /* set default policy */
> ret = cpufreq_set_policy(policy, &new_policy);
> @@ -944,11 +953,11 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
> unsigned long flags;
>
> read_lock_irqsave(&cpufreq_driver_lock, flags);
> -
> policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
> -
Why do these whitespace changes belong to this patch?
> read_unlock_irqrestore(&cpufreq_driver_lock, flags);
>
> + policy->governor = NULL;
> +
> return policy;
> }
>
> @@ -1036,7 +1045,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
> unsigned long flags;
> #ifdef CONFIG_HOTPLUG_CPU
> struct cpufreq_policy *tpolicy;
> - struct cpufreq_governor *gov;
> #endif
>
> if (cpu_is_offline(cpu))
> @@ -1094,7 +1102,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
> else
> policy->cpu = cpu;
>
> - policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
> cpumask_copy(policy->cpus, cpumask_of(cpu));
>
> init_completion(&policy->kobj_unregister);
> @@ -1179,15 +1186,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
> blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
> CPUFREQ_START, policy);
>
> -#ifdef CONFIG_HOTPLUG_CPU
> - gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
> - if (gov) {
> - policy->governor = gov;
> - pr_debug("Restoring governor %s for cpu %d\n",
> - policy->governor->name, cpu);
> - }
> -#endif
> -
> if (!frozen) {
> ret = cpufreq_add_dev_interface(policy, dev);
> if (ret)
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/3] cpufreq: Initialize policy before making it available for others to use
2014-02-25 8:50 ` [PATCH 2/3] cpufreq: Initialize policy before making it available for others to use Viresh Kumar
@ 2014-03-01 1:14 ` Rafael J. Wysocki
0 siblings, 0 replies; 7+ messages in thread
From: Rafael J. Wysocki @ 2014-03-01 1:14 UTC (permalink / raw)
To: Viresh Kumar
Cc: skannan, linaro-kernel, cpufreq, linux-pm, linux-kernel, srivatsa.bhat
On Tuesday, February 25, 2014 02:20:10 PM Viresh Kumar wrote:
> Policy must be fully initialized before it is being made available for use by
> others.
True enough. And the problem is?
> This patch moves some initialization code before making policy available
> for others.
So why/how exactly does this fix the problem?
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> drivers/cpufreq/cpufreq.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index cc4f244..110c0cd 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1116,6 +1116,20 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
> goto err_set_policy_cpu;
> }
>
> + /* related cpus should atleast have policy->cpus */
> + cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
> +
> + /*
> + * affected cpus must always be the one, which are online. We aren't
> + * managing offline cpus here.
> + */
> + cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
> +
> + if (!frozen) {
> + policy->user_policy.min = policy->min;
> + policy->user_policy.max = policy->max;
> + }
> +
> write_lock_irqsave(&cpufreq_driver_lock, flags);
> for_each_cpu(j, policy->cpus)
> per_cpu(cpufreq_cpu_data, j) = policy;
> @@ -1169,20 +1183,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
> }
> }
>
> - /* related cpus should atleast have policy->cpus */
> - cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
> -
> - /*
> - * affected cpus must always be the one, which are online. We aren't
> - * managing offline cpus here.
> - */
> - cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
> -
> - if (!frozen) {
> - policy->user_policy.min = policy->min;
> - policy->user_policy.max = policy->max;
> - }
> -
> blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
> CPUFREQ_START, policy);
>
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy()
2014-03-01 1:09 ` Rafael J. Wysocki
@ 2014-03-04 3:43 ` Viresh Kumar
0 siblings, 0 replies; 7+ messages in thread
From: Viresh Kumar @ 2014-03-04 3:43 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Saravana Kannan, Lists linaro-kernel, cpufreq, linux-pm,
Linux Kernel Mailing List, Srivatsa S. Bhat
On 1 March 2014 06:39, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> And while I'm at it, can we *please* avoid adding new #ifdef blocks into
> function bodies?
>
> Please introduce a wrapper around __find_governor() returning NULL for
> CONFIG_HOTPLUG_CPU unset.
I have tried fixing all the suggestions you gave for this series. Please have a
look at V2 set and let me know if I am still missing anything.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2014-03-04 3:43 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-02-25 8:50 [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy() Viresh Kumar
2014-02-25 8:50 ` [PATCH 2/3] cpufreq: Initialize policy before making it available for others to use Viresh Kumar
2014-03-01 1:14 ` Rafael J. Wysocki
2014-02-25 8:50 ` [PATCH 3/3] cpufreq: initialize governor for a new policy under policy->rwsem Viresh Kumar
2014-03-01 1:00 ` [PATCH 1/3] cpufreq: move call to __find_governor() to cpufreq_init_policy() Rafael J. Wysocki
2014-03-01 1:09 ` Rafael J. Wysocki
2014-03-04 3:43 ` Viresh Kumar
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