subject:"\[RFT\]\[PATCH v2 2\/2\] PM \/ QoS\: Fix device resume latency framework"

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-04 Thread Rafael J. Wysocki

On Sat, Nov 4, 2017 at 12:30 PM, Rafael J. Wysocki  wrote:
> On Sat, Nov 4, 2017 at 3:28 AM, Ramesh Thomas  wrote:
>> On 2017-11-03 at 09:39:08 -0700, Reinette Chatre wrote:
>>> Hi Rafael,
>>>
>>> I started to test this but found myself triggering one of the warnings:
>>>
>>> On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
>>> > --- linux-pm.orig/include/linux/pm_qos.h
>>> > +++ linux-pm/include/linux/pm_qos.h
>>> > @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>>> > PM_QOS_FLAGS_ALL,
>>> >  };
>>> >
>>> > -#define PM_QOS_DEFAULT_VALUE -1
>>> > +#define PM_QOS_DEFAULT_VALUE   (-1)
>>>
>>> PM_QOS_DEFAULT_VALUE is -1 ...
>>>
>>>
>>> > ===
>>> > --- linux-pm.orig/drivers/base/power/qos.c
>>> > +++ linux-pm/drivers/base/power/qos.c
>>> > @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
>>> >
>>> > switch(req->type) {
>>> > case DEV_PM_QOS_RESUME_LATENCY:
>>> > +   if (WARN_ON(value < 0))
>>> > +   value = 0;
>>> > +
>>>
>>> ... causing me to hit this WARN_ON because apply_constraint() is called by 
>>> __dev_pm_qos_remove_request() with the value parameter set to 
>>> PM_QOS_DEFAULT_VALUE.
>>
>> That value does not get used if action is PM_QOS_REMOVE_REQ. May be just pass
>> 0 or PM_QOS_RESUME_LATENCY_DEFAULT_VALUE everywhere apply_constraint is 
>> called
>> with PM_QOS_REMOVE_REQ action.
>
> I think it's better to pass the "no constraint" value as that should
> not reorder it to the top of the list.

Actually, no.  The value is ignored if action is PM_QOS_REMOVE_REQ, so
it is better to simply check the action under the WARN_ON() too.

Thanks,
Rafael

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-04 Thread Rafael J. Wysocki

On Sat, Nov 4, 2017 at 12:30 PM, Rafael J. Wysocki  wrote:
> On Sat, Nov 4, 2017 at 3:28 AM, Ramesh Thomas  wrote:
>> On 2017-11-03 at 09:39:08 -0700, Reinette Chatre wrote:
>>> Hi Rafael,
>>>
>>> I started to test this but found myself triggering one of the warnings:
>>>
>>> On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
>>> > --- linux-pm.orig/include/linux/pm_qos.h
>>> > +++ linux-pm/include/linux/pm_qos.h
>>> > @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>>> > PM_QOS_FLAGS_ALL,
>>> >  };
>>> >
>>> > -#define PM_QOS_DEFAULT_VALUE -1
>>> > +#define PM_QOS_DEFAULT_VALUE   (-1)
>>>
>>> PM_QOS_DEFAULT_VALUE is -1 ...
>>>
>>>
>>> > ===
>>> > --- linux-pm.orig/drivers/base/power/qos.c
>>> > +++ linux-pm/drivers/base/power/qos.c
>>> > @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
>>> >
>>> > switch(req->type) {
>>> > case DEV_PM_QOS_RESUME_LATENCY:
>>> > +   if (WARN_ON(value < 0))
>>> > +   value = 0;
>>> > +
>>>
>>> ... causing me to hit this WARN_ON because apply_constraint() is called by 
>>> __dev_pm_qos_remove_request() with the value parameter set to 
>>> PM_QOS_DEFAULT_VALUE.
>>
>> That value does not get used if action is PM_QOS_REMOVE_REQ. May be just pass
>> 0 or PM_QOS_RESUME_LATENCY_DEFAULT_VALUE everywhere apply_constraint is 
>> called
>> with PM_QOS_REMOVE_REQ action.
>
> I think it's better to pass the "no constraint" value as that should
> not reorder it to the top of the list.

Actually, no.  The value is ignored if action is PM_QOS_REMOVE_REQ, so
it is better to simply check the action under the WARN_ON() too.

Thanks,
Rafael

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-04 Thread Rafael J. Wysocki

On Sat, Nov 4, 2017 at 3:28 AM, Ramesh Thomas  wrote:
> On 2017-11-03 at 09:39:08 -0700, Reinette Chatre wrote:
>> Hi Rafael,
>>
>> I started to test this but found myself triggering one of the warnings:
>>
>> On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
>> > --- linux-pm.orig/include/linux/pm_qos.h
>> > +++ linux-pm/include/linux/pm_qos.h
>> > @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>> > PM_QOS_FLAGS_ALL,
>> >  };
>> >
>> > -#define PM_QOS_DEFAULT_VALUE -1
>> > +#define PM_QOS_DEFAULT_VALUE   (-1)
>>
>> PM_QOS_DEFAULT_VALUE is -1 ...
>>
>>
>> > ===
>> > --- linux-pm.orig/drivers/base/power/qos.c
>> > +++ linux-pm/drivers/base/power/qos.c
>> > @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
>> >
>> > switch(req->type) {
>> > case DEV_PM_QOS_RESUME_LATENCY:
>> > +   if (WARN_ON(value < 0))
>> > +   value = 0;
>> > +
>>
>> ... causing me to hit this WARN_ON because apply_constraint() is called by 
>> __dev_pm_qos_remove_request() with the value parameter set to 
>> PM_QOS_DEFAULT_VALUE.
>
> That value does not get used if action is PM_QOS_REMOVE_REQ. May be just pass
> 0 or PM_QOS_RESUME_LATENCY_DEFAULT_VALUE everywhere apply_constraint is called
> with PM_QOS_REMOVE_REQ action.

I think it's better to pass the "no constraint" value as that should
not reorder it to the top of the list.

Thanks,
Rafael

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-04 Thread Rafael J. Wysocki

On Sat, Nov 4, 2017 at 3:28 AM, Ramesh Thomas  wrote:
> On 2017-11-03 at 09:39:08 -0700, Reinette Chatre wrote:
>> Hi Rafael,
>>
>> I started to test this but found myself triggering one of the warnings:
>>
>> On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
>> > --- linux-pm.orig/include/linux/pm_qos.h
>> > +++ linux-pm/include/linux/pm_qos.h
>> > @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>> > PM_QOS_FLAGS_ALL,
>> >  };
>> >
>> > -#define PM_QOS_DEFAULT_VALUE -1
>> > +#define PM_QOS_DEFAULT_VALUE   (-1)
>>
>> PM_QOS_DEFAULT_VALUE is -1 ...
>>
>>
>> > ===
>> > --- linux-pm.orig/drivers/base/power/qos.c
>> > +++ linux-pm/drivers/base/power/qos.c
>> > @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
>> >
>> > switch(req->type) {
>> > case DEV_PM_QOS_RESUME_LATENCY:
>> > +   if (WARN_ON(value < 0))
>> > +   value = 0;
>> > +
>>
>> ... causing me to hit this WARN_ON because apply_constraint() is called by 
>> __dev_pm_qos_remove_request() with the value parameter set to 
>> PM_QOS_DEFAULT_VALUE.
>
> That value does not get used if action is PM_QOS_REMOVE_REQ. May be just pass
> 0 or PM_QOS_RESUME_LATENCY_DEFAULT_VALUE everywhere apply_constraint is called
> with PM_QOS_REMOVE_REQ action.

I think it's better to pass the "no constraint" value as that should
not reorder it to the top of the list.

Thanks,
Rafael

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-04 Thread Rafael J. Wysocki

On Fri, Nov 3, 2017 at 5:39 PM, Reinette Chatre
 wrote:
> Hi Rafael,
>
> I started to test this but found myself triggering one of the warnings:
>
> On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
>> --- linux-pm.orig/include/linux/pm_qos.h
>> +++ linux-pm/include/linux/pm_qos.h
>> @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>>   PM_QOS_FLAGS_ALL,
>>  };
>>
>> -#define PM_QOS_DEFAULT_VALUE -1
>> +#define PM_QOS_DEFAULT_VALUE (-1)
>
> PM_QOS_DEFAULT_VALUE is -1 ...
>
>
>> ===
>> --- linux-pm.orig/drivers/base/power/qos.c
>> +++ linux-pm/drivers/base/power/qos.c
>> @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
>>
>>   switch(req->type) {
>>   case DEV_PM_QOS_RESUME_LATENCY:
>> + if (WARN_ON(value < 0))
>> + value = 0;
>> +
>
> ... causing me to hit this WARN_ON because apply_constraint() is called by 
> __dev_pm_qos_remove_request() with the value parameter set to 
> PM_QOS_DEFAULT_VALUE.

Thanks for the report!

I've added it to catch bugs in the future, but it has caught a bug
right away. :-)

That actually is a bug in the existing code that needs to be fixed.

Thanks,
Rafael

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-04 Thread Rafael J. Wysocki

On Fri, Nov 3, 2017 at 5:39 PM, Reinette Chatre
 wrote:
> Hi Rafael,
>
> I started to test this but found myself triggering one of the warnings:
>
> On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
>> --- linux-pm.orig/include/linux/pm_qos.h
>> +++ linux-pm/include/linux/pm_qos.h
>> @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>>   PM_QOS_FLAGS_ALL,
>>  };
>>
>> -#define PM_QOS_DEFAULT_VALUE -1
>> +#define PM_QOS_DEFAULT_VALUE (-1)
>
> PM_QOS_DEFAULT_VALUE is -1 ...
>
>
>> ===
>> --- linux-pm.orig/drivers/base/power/qos.c
>> +++ linux-pm/drivers/base/power/qos.c
>> @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
>>
>>   switch(req->type) {
>>   case DEV_PM_QOS_RESUME_LATENCY:
>> + if (WARN_ON(value < 0))
>> + value = 0;
>> +
>
> ... causing me to hit this WARN_ON because apply_constraint() is called by 
> __dev_pm_qos_remove_request() with the value parameter set to 
> PM_QOS_DEFAULT_VALUE.

Thanks for the report!

I've added it to catch bugs in the future, but it has caught a bug
right away. :-)

That actually is a bug in the existing code that needs to be fixed.

Thanks,
Rafael

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-03 Thread Ramesh Thomas

On 2017-11-03 at 12:50:15 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki 
> 
> The special value of 0 for device resume latency PM QoS means
> "no restriction", but there are two problems with that.
> 
> First, device resume latency PM QoS requests with 0 as the
> value are always put in front of requests with positive
> values in the priority lists used internally by the PM QoS
> framework, causing 0 to be chosen as an effective constraint
> value.  However, that 0 is then interpreted as "no restriction"
> effectively overriding the other requests with specific
> restrictions which is incorrect.
> 
> Second, the users of device resume latency PM QoS have no
> way to specify that *any* resume latency at all should be
> avoided, which is an artificial limitation in general.
> 
> To address these issues, modify device resume latency PM QoS to
> use S32_MAX as the "no constraint" value and 0 as the "no
> latency at all" one and rework its users (the cpuidle menu
> governor, the genpd QoS governor and the runtime PM framework)
> to follow these changes.
> 
> Also add a special "n/a" value to the corresponding user space I/F
> to allow user space to indicate that it cannot accept any resume
> latencies at all for the given device.
> 
> Fixes: 85dc0b8a4019 (PM / QoS: Make it possible to expose PM QoS latency 
> constraints)
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323
> Reported-by: Reinette Chatre 
> Signed-off-by: Rafael J. Wysocki 
> ---
>  Documentation/ABI/testing/sysfs-devices-power |4 +++-
>  drivers/base/cpu.c|3 ++-
>  drivers/base/power/domain.c   |2 +-
>  drivers/base/power/domain_governor.c  |   26 
> ++
>  drivers/base/power/qos.c  |5 -
>  drivers/base/power/runtime.c  |2 +-
>  drivers/base/power/sysfs.c|   25 
> +
>  drivers/cpuidle/governors/menu.c  |4 ++--
>  include/linux/pm_qos.h|   26 
> ++
>  9 files changed, 62 insertions(+), 35 deletions(-)
> 
> Index: linux-pm/drivers/base/power/sysfs.c
> ===
> --- linux-pm.orig/drivers/base/power/sysfs.c
> +++ linux-pm/drivers/base/power/sysfs.c
> @@ -218,7 +218,14 @@ static ssize_t pm_qos_resume_latency_sho
> struct device_attribute *attr,
> char *buf)
>  {
> - return sprintf(buf, "%d\n", dev_pm_qos_requested_resume_latency(dev));
> + s32 value = dev_pm_qos_requested_resume_latency(dev);
> +
> + if (value == 0)
> + return sprintf(buf, "n/a\n");
> + else if (value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
> + value = 0;
> +
> + return sprintf(buf, "%d\n", value);
>  }
>  
>  static ssize_t pm_qos_resume_latency_store(struct device *dev,
> @@ -228,11 +235,21 @@ static ssize_t pm_qos_resume_latency_sto
>   s32 value;
>   int ret;
>  
> - if (kstrtos32(buf, 0, ))
> - return -EINVAL;
> + if (!kstrtos32(buf, 0, )) {
> + /*
> +  * Prevent users from writing negative or "no constraint" values
> +  * directly.
> +  */
> + if (value < 0 || value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
> + return -EINVAL;
>  
> - if (value < 0)
> + if (value == 0)
> + value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
> + } else if (!strcmp(buf, "n/a") || !strcmp(buf, "n/a\n")) {
> + value = 0;
> + } else {
>   return -EINVAL;
> + }
>  
>   ret = dev_pm_qos_update_request(dev->power.qos->resume_latency_req,
>   value);
> Index: linux-pm/include/linux/pm_qos.h
> ===
> --- linux-pm.orig/include/linux/pm_qos.h
> +++ linux-pm/include/linux/pm_qos.h
> @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>   PM_QOS_FLAGS_ALL,
>  };
>  
> -#define PM_QOS_DEFAULT_VALUE -1
> +#define PM_QOS_DEFAULT_VALUE (-1)
> +#define PM_QOS_LATENCY_ANY   S32_MAX
> +#define PM_QOS_LATENCY_ANY_NS((s64)PM_QOS_LATENCY_ANY * 
> NSEC_PER_USEC)
>  
>  #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
>  #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
>  #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE  0
>  #define PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE0
> -#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE  0
> +#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE  PM_QOS_LATENCY_ANY
> +#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT  PM_QOS_LATENCY_ANY
> +#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS   PM_QOS_LATENCY_ANY_NS
>  #define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-03 Thread Ramesh Thomas

On 2017-11-03 at 12:50:15 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki 
> 
> The special value of 0 for device resume latency PM QoS means
> "no restriction", but there are two problems with that.
> 
> First, device resume latency PM QoS requests with 0 as the
> value are always put in front of requests with positive
> values in the priority lists used internally by the PM QoS
> framework, causing 0 to be chosen as an effective constraint
> value.  However, that 0 is then interpreted as "no restriction"
> effectively overriding the other requests with specific
> restrictions which is incorrect.
> 
> Second, the users of device resume latency PM QoS have no
> way to specify that *any* resume latency at all should be
> avoided, which is an artificial limitation in general.
> 
> To address these issues, modify device resume latency PM QoS to
> use S32_MAX as the "no constraint" value and 0 as the "no
> latency at all" one and rework its users (the cpuidle menu
> governor, the genpd QoS governor and the runtime PM framework)
> to follow these changes.
> 
> Also add a special "n/a" value to the corresponding user space I/F
> to allow user space to indicate that it cannot accept any resume
> latencies at all for the given device.
> 
> Fixes: 85dc0b8a4019 (PM / QoS: Make it possible to expose PM QoS latency 
> constraints)
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323
> Reported-by: Reinette Chatre 
> Signed-off-by: Rafael J. Wysocki 
> ---
>  Documentation/ABI/testing/sysfs-devices-power |4 +++-
>  drivers/base/cpu.c|3 ++-
>  drivers/base/power/domain.c   |2 +-
>  drivers/base/power/domain_governor.c  |   26 
> ++
>  drivers/base/power/qos.c  |5 -
>  drivers/base/power/runtime.c  |2 +-
>  drivers/base/power/sysfs.c|   25 
> +
>  drivers/cpuidle/governors/menu.c  |4 ++--
>  include/linux/pm_qos.h|   26 
> ++
>  9 files changed, 62 insertions(+), 35 deletions(-)
> 
> Index: linux-pm/drivers/base/power/sysfs.c
> ===
> --- linux-pm.orig/drivers/base/power/sysfs.c
> +++ linux-pm/drivers/base/power/sysfs.c
> @@ -218,7 +218,14 @@ static ssize_t pm_qos_resume_latency_sho
> struct device_attribute *attr,
> char *buf)
>  {
> - return sprintf(buf, "%d\n", dev_pm_qos_requested_resume_latency(dev));
> + s32 value = dev_pm_qos_requested_resume_latency(dev);
> +
> + if (value == 0)
> + return sprintf(buf, "n/a\n");
> + else if (value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
> + value = 0;
> +
> + return sprintf(buf, "%d\n", value);
>  }
>  
>  static ssize_t pm_qos_resume_latency_store(struct device *dev,
> @@ -228,11 +235,21 @@ static ssize_t pm_qos_resume_latency_sto
>   s32 value;
>   int ret;
>  
> - if (kstrtos32(buf, 0, ))
> - return -EINVAL;
> + if (!kstrtos32(buf, 0, )) {
> + /*
> +  * Prevent users from writing negative or "no constraint" values
> +  * directly.
> +  */
> + if (value < 0 || value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
> + return -EINVAL;
>  
> - if (value < 0)
> + if (value == 0)
> + value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
> + } else if (!strcmp(buf, "n/a") || !strcmp(buf, "n/a\n")) {
> + value = 0;
> + } else {
>   return -EINVAL;
> + }
>  
>   ret = dev_pm_qos_update_request(dev->power.qos->resume_latency_req,
>   value);
> Index: linux-pm/include/linux/pm_qos.h
> ===
> --- linux-pm.orig/include/linux/pm_qos.h
> +++ linux-pm/include/linux/pm_qos.h
> @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>   PM_QOS_FLAGS_ALL,
>  };
>  
> -#define PM_QOS_DEFAULT_VALUE -1
> +#define PM_QOS_DEFAULT_VALUE (-1)
> +#define PM_QOS_LATENCY_ANY   S32_MAX
> +#define PM_QOS_LATENCY_ANY_NS((s64)PM_QOS_LATENCY_ANY * 
> NSEC_PER_USEC)
>  
>  #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
>  #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
>  #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE  0
>  #define PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE0
> -#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE  0
> +#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE  PM_QOS_LATENCY_ANY
> +#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT  PM_QOS_LATENCY_ANY
> +#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS   PM_QOS_LATENCY_ANY_NS
>  #define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE   0
>  #define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT   (-1)
> -#define

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-03 Thread Ramesh Thomas

On 2017-11-03 at 09:39:08 -0700, Reinette Chatre wrote:
> Hi Rafael,
> 
> I started to test this but found myself triggering one of the warnings:
> 
> On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
> > --- linux-pm.orig/include/linux/pm_qos.h
> > +++ linux-pm/include/linux/pm_qos.h
> > @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
> > PM_QOS_FLAGS_ALL,
> >  };
> >  
> > -#define PM_QOS_DEFAULT_VALUE -1
> > +#define PM_QOS_DEFAULT_VALUE   (-1)
> 
> PM_QOS_DEFAULT_VALUE is -1 ...
> 
> 
> > ===
> > --- linux-pm.orig/drivers/base/power/qos.c
> > +++ linux-pm/drivers/base/power/qos.c
> > @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
> >  
> > switch(req->type) {
> > case DEV_PM_QOS_RESUME_LATENCY:
> > +   if (WARN_ON(value < 0))
> > +   value = 0;
> > +
> 
> ... causing me to hit this WARN_ON because apply_constraint() is called by 
> __dev_pm_qos_remove_request() with the value parameter set to 
> PM_QOS_DEFAULT_VALUE.

That value does not get used if action is PM_QOS_REMOVE_REQ. May be just pass
0 or PM_QOS_RESUME_LATENCY_DEFAULT_VALUE everywhere apply_constraint is called
with PM_QOS_REMOVE_REQ action.

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-03 Thread Ramesh Thomas

On 2017-11-03 at 09:39:08 -0700, Reinette Chatre wrote:
> Hi Rafael,
> 
> I started to test this but found myself triggering one of the warnings:
> 
> On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
> > --- linux-pm.orig/include/linux/pm_qos.h
> > +++ linux-pm/include/linux/pm_qos.h
> > @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
> > PM_QOS_FLAGS_ALL,
> >  };
> >  
> > -#define PM_QOS_DEFAULT_VALUE -1
> > +#define PM_QOS_DEFAULT_VALUE   (-1)
> 
> PM_QOS_DEFAULT_VALUE is -1 ...
> 
> 
> > ===
> > --- linux-pm.orig/drivers/base/power/qos.c
> > +++ linux-pm/drivers/base/power/qos.c
> > @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
> >  
> > switch(req->type) {
> > case DEV_PM_QOS_RESUME_LATENCY:
> > +   if (WARN_ON(value < 0))
> > +   value = 0;
> > +
> 
> ... causing me to hit this WARN_ON because apply_constraint() is called by 
> __dev_pm_qos_remove_request() with the value parameter set to 
> PM_QOS_DEFAULT_VALUE.

That value does not get used if action is PM_QOS_REMOVE_REQ. May be just pass
0 or PM_QOS_RESUME_LATENCY_DEFAULT_VALUE everywhere apply_constraint is called
with PM_QOS_REMOVE_REQ action.

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-03 Thread Reinette Chatre

Hi Rafael,

I started to test this but found myself triggering one of the warnings:

On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
> --- linux-pm.orig/include/linux/pm_qos.h
> +++ linux-pm/include/linux/pm_qos.h
> @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>   PM_QOS_FLAGS_ALL,
>  };
>  
> -#define PM_QOS_DEFAULT_VALUE -1
> +#define PM_QOS_DEFAULT_VALUE (-1)

PM_QOS_DEFAULT_VALUE is -1 ...


> ===
> --- linux-pm.orig/drivers/base/power/qos.c
> +++ linux-pm/drivers/base/power/qos.c
> @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
>  
>   switch(req->type) {
>   case DEV_PM_QOS_RESUME_LATENCY:
> + if (WARN_ON(value < 0))
> + value = 0;
> +

... causing me to hit this WARN_ON because apply_constraint() is called by 
__dev_pm_qos_remove_request() with the value parameter set to 
PM_QOS_DEFAULT_VALUE.

Reinette

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-03 Thread Reinette Chatre

Hi Rafael,

I started to test this but found myself triggering one of the warnings:

On 11/3/2017 4:50 AM, Rafael J. Wysocki wrote:
> --- linux-pm.orig/include/linux/pm_qos.h
> +++ linux-pm/include/linux/pm_qos.h
> @@ -28,16 +28,19 @@ enum pm_qos_flags_status {
>   PM_QOS_FLAGS_ALL,
>  };
>  
> -#define PM_QOS_DEFAULT_VALUE -1
> +#define PM_QOS_DEFAULT_VALUE (-1)

PM_QOS_DEFAULT_VALUE is -1 ...


> ===
> --- linux-pm.orig/drivers/base/power/qos.c
> +++ linux-pm/drivers/base/power/qos.c
> @@ -139,6 +139,9 @@ static int apply_constraint(struct dev_p
>  
>   switch(req->type) {
>   case DEV_PM_QOS_RESUME_LATENCY:
> + if (WARN_ON(value < 0))
> + value = 0;
> +

... causing me to hit this WARN_ON because apply_constraint() is called by 
__dev_pm_qos_remove_request() with the value parameter set to 
PM_QOS_DEFAULT_VALUE.

Reinette

[RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-03 Thread Rafael J. Wysocki

From: Rafael J. Wysocki 

The special value of 0 for device resume latency PM QoS means
"no restriction", but there are two problems with that.

First, device resume latency PM QoS requests with 0 as the
value are always put in front of requests with positive
values in the priority lists used internally by the PM QoS
framework, causing 0 to be chosen as an effective constraint
value.  However, that 0 is then interpreted as "no restriction"
effectively overriding the other requests with specific
restrictions which is incorrect.

Second, the users of device resume latency PM QoS have no
way to specify that *any* resume latency at all should be
avoided, which is an artificial limitation in general.

To address these issues, modify device resume latency PM QoS to
use S32_MAX as the "no constraint" value and 0 as the "no
latency at all" one and rework its users (the cpuidle menu
governor, the genpd QoS governor and the runtime PM framework)
to follow these changes.

Also add a special "n/a" value to the corresponding user space I/F
to allow user space to indicate that it cannot accept any resume
latencies at all for the given device.

Fixes: 85dc0b8a4019 (PM / QoS: Make it possible to expose PM QoS latency 
constraints)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323
Reported-by: Reinette Chatre 
Signed-off-by: Rafael J. Wysocki 
---
 Documentation/ABI/testing/sysfs-devices-power |4 +++-
 drivers/base/cpu.c|3 ++-
 drivers/base/power/domain.c   |2 +-
 drivers/base/power/domain_governor.c  |   26 ++
 drivers/base/power/qos.c  |5 -
 drivers/base/power/runtime.c  |2 +-
 drivers/base/power/sysfs.c|   25 +
 drivers/cpuidle/governors/menu.c  |4 ++--
 include/linux/pm_qos.h|   26 ++
 9 files changed, 62 insertions(+), 35 deletions(-)

Index: linux-pm/drivers/base/power/sysfs.c
===
--- linux-pm.orig/drivers/base/power/sysfs.c
+++ linux-pm/drivers/base/power/sysfs.c
@@ -218,7 +218,14 @@ static ssize_t pm_qos_resume_latency_sho
  struct device_attribute *attr,
  char *buf)
 {
-   return sprintf(buf, "%d\n", dev_pm_qos_requested_resume_latency(dev));
+   s32 value = dev_pm_qos_requested_resume_latency(dev);
+
+   if (value == 0)
+   return sprintf(buf, "n/a\n");
+   else if (value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
+   value = 0;
+
+   return sprintf(buf, "%d\n", value);
 }
 
 static ssize_t pm_qos_resume_latency_store(struct device *dev,
@@ -228,11 +235,21 @@ static ssize_t pm_qos_resume_latency_sto
s32 value;
int ret;
 
-   if (kstrtos32(buf, 0, ))
-   return -EINVAL;
+   if (!kstrtos32(buf, 0, )) {
+   /*
+* Prevent users from writing negative or "no constraint" values
+* directly.
+*/
+   if (value < 0 || value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
+   return -EINVAL;
 
-   if (value < 0)
+   if (value == 0)
+   value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
+   } else if (!strcmp(buf, "n/a") || !strcmp(buf, "n/a\n")) {
+   value = 0;
+   } else {
return -EINVAL;
+   }
 
ret = dev_pm_qos_update_request(dev->power.qos->resume_latency_req,
value);
Index: linux-pm/include/linux/pm_qos.h
===
--- linux-pm.orig/include/linux/pm_qos.h
+++ linux-pm/include/linux/pm_qos.h
@@ -28,16 +28,19 @@ enum pm_qos_flags_status {
PM_QOS_FLAGS_ALL,
 };
 
-#define PM_QOS_DEFAULT_VALUE -1
+#define PM_QOS_DEFAULT_VALUE   (-1)
+#define PM_QOS_LATENCY_ANY S32_MAX
+#define PM_QOS_LATENCY_ANY_NS  ((s64)PM_QOS_LATENCY_ANY * NSEC_PER_USEC)
 
 #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE   (2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE   (2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE0
 #define PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE  0
-#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE0
+#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUEPM_QOS_LATENCY_ANY
+#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINTPM_QOS_LATENCY_ANY
+#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS PM_QOS_LATENCY_ANY_NS
 #define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE 0
 #define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT (-1)
-#define PM_QOS_LATENCY_ANY ((s32)(~(__u32)0 >> 1))
 
 #define PM_QOS_FLAG_NO_POWER_OFF   (1 << 0)
 
@@ -174,7 +177,8 @@ static inline s32

[RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

2017-11-03 Thread Rafael J. Wysocki

From: Rafael J. Wysocki 

The special value of 0 for device resume latency PM QoS means
"no restriction", but there are two problems with that.

First, device resume latency PM QoS requests with 0 as the
value are always put in front of requests with positive
values in the priority lists used internally by the PM QoS
framework, causing 0 to be chosen as an effective constraint
value.  However, that 0 is then interpreted as "no restriction"
effectively overriding the other requests with specific
restrictions which is incorrect.

Second, the users of device resume latency PM QoS have no
way to specify that *any* resume latency at all should be
avoided, which is an artificial limitation in general.

To address these issues, modify device resume latency PM QoS to
use S32_MAX as the "no constraint" value and 0 as the "no
latency at all" one and rework its users (the cpuidle menu
governor, the genpd QoS governor and the runtime PM framework)
to follow these changes.

Also add a special "n/a" value to the corresponding user space I/F
to allow user space to indicate that it cannot accept any resume
latencies at all for the given device.

Fixes: 85dc0b8a4019 (PM / QoS: Make it possible to expose PM QoS latency 
constraints)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323
Reported-by: Reinette Chatre 
Signed-off-by: Rafael J. Wysocki 
---
 Documentation/ABI/testing/sysfs-devices-power |4 +++-
 drivers/base/cpu.c|3 ++-
 drivers/base/power/domain.c   |2 +-
 drivers/base/power/domain_governor.c  |   26 ++
 drivers/base/power/qos.c  |5 -
 drivers/base/power/runtime.c  |2 +-
 drivers/base/power/sysfs.c|   25 +
 drivers/cpuidle/governors/menu.c  |4 ++--
 include/linux/pm_qos.h|   26 ++
 9 files changed, 62 insertions(+), 35 deletions(-)

Index: linux-pm/drivers/base/power/sysfs.c
===
--- linux-pm.orig/drivers/base/power/sysfs.c
+++ linux-pm/drivers/base/power/sysfs.c
@@ -218,7 +218,14 @@ static ssize_t pm_qos_resume_latency_sho
  struct device_attribute *attr,
  char *buf)
 {
-   return sprintf(buf, "%d\n", dev_pm_qos_requested_resume_latency(dev));
+   s32 value = dev_pm_qos_requested_resume_latency(dev);
+
+   if (value == 0)
+   return sprintf(buf, "n/a\n");
+   else if (value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
+   value = 0;
+
+   return sprintf(buf, "%d\n", value);
 }
 
 static ssize_t pm_qos_resume_latency_store(struct device *dev,
@@ -228,11 +235,21 @@ static ssize_t pm_qos_resume_latency_sto
s32 value;
int ret;
 
-   if (kstrtos32(buf, 0, ))
-   return -EINVAL;
+   if (!kstrtos32(buf, 0, )) {
+   /*
+* Prevent users from writing negative or "no constraint" values
+* directly.
+*/
+   if (value < 0 || value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
+   return -EINVAL;
 
-   if (value < 0)
+   if (value == 0)
+   value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
+   } else if (!strcmp(buf, "n/a") || !strcmp(buf, "n/a\n")) {
+   value = 0;
+   } else {
return -EINVAL;
+   }
 
ret = dev_pm_qos_update_request(dev->power.qos->resume_latency_req,
value);
Index: linux-pm/include/linux/pm_qos.h
===
--- linux-pm.orig/include/linux/pm_qos.h
+++ linux-pm/include/linux/pm_qos.h
@@ -28,16 +28,19 @@ enum pm_qos_flags_status {
PM_QOS_FLAGS_ALL,
 };
 
-#define PM_QOS_DEFAULT_VALUE -1
+#define PM_QOS_DEFAULT_VALUE   (-1)
+#define PM_QOS_LATENCY_ANY S32_MAX
+#define PM_QOS_LATENCY_ANY_NS  ((s64)PM_QOS_LATENCY_ANY * NSEC_PER_USEC)
 
 #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE   (2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE   (2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE0
 #define PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE  0
-#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE0
+#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUEPM_QOS_LATENCY_ANY
+#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINTPM_QOS_LATENCY_ANY
+#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS PM_QOS_LATENCY_ANY_NS
 #define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE 0
 #define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT (-1)
-#define PM_QOS_LATENCY_ANY ((s32)(~(__u32)0 >> 1))
 
 #define PM_QOS_FLAG_NO_POWER_OFF   (1 << 0)
 
@@ -174,7 +177,8 @@ static inline s32 dev_pm_qos_requested_f
 static inline s32 dev_pm_qos_raw_read_value(struct device *dev)
 {

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

Re: [RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

[RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

[RFT][PATCH v2 2/2] PM / QoS: Fix device resume latency framework

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