Re: [PATCH 1/7] PM / QoS: Prepare device structure for adding moreconstraint types

[mark gross]

On Mon, Oct 08, 2012 at 10:04:03AM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> 
> Currently struct dev_pm_info contains only one PM QoS constraints
> pointer reserved for latency requirements.  Since one more device
> constraints type (i.e. flags) will be necessary, introduce a new
> structure, struct dev_pm_qos, that eventually will contain all of
> the available device PM QoS constraints and replace the "constraints"
> pointer in struct dev_pm_info with a pointer to the new structure
> called "qos".
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Reviewed-by: Jean Pihet <j-pihet@xxxxxx>
> ---
>  drivers/base/power/qos.c |   42 ++++++++++++++++++++++--------------------
>  include/linux/pm.h       |    2 +-
>  include/linux/pm_qos.h   |    4 ++++
>  3 files changed, 27 insertions(+), 21 deletions(-)
> 
> Index: linux/include/linux/pm.h
> ===================================================================
> --- linux.orig/include/linux/pm.h
> +++ linux/include/linux/pm.h
> @@ -551,7 +551,7 @@ struct dev_pm_info {
>  	struct dev_pm_qos_request *pq_req;
>  #endif
>  	struct pm_subsys_data	*subsys_data;  /* Owned by the subsystem. */
> -	struct pm_qos_constraints *constraints;
> +	struct dev_pm_qos	*qos;
>  };
>  
>  extern void update_pm_runtime_accounting(struct device *dev);
> Index: linux/include/linux/pm_qos.h
> ===================================================================
> --- linux.orig/include/linux/pm_qos.h
> +++ linux/include/linux/pm_qos.h
> @@ -57,6 +57,10 @@ struct pm_qos_constraints {
>  	struct blocking_notifier_head *notifiers;
>  };
>  
> +struct dev_pm_qos {
> +	struct pm_qos_constraints latency;
What about non-latency constraints?  This pretty much makes it explicit
that dev_pm_qos is all about latency.  from the commit comment I thought
you where trying to make it more genaric.  Why not call "latency"
"constraint" or something less specific?

--mark

> +};
> +
>  /* Action requested to pm_qos_update_target */
>  enum pm_qos_req_action {
>  	PM_QOS_ADD_REQ,		/* Add a new request */
> Index: linux/drivers/base/power/qos.c
> ===================================================================
> --- linux.orig/drivers/base/power/qos.c
> +++ linux/drivers/base/power/qos.c
> @@ -55,9 +55,7 @@ static BLOCKING_NOTIFIER_HEAD(dev_pm_not
>   */
>  s32 __dev_pm_qos_read_value(struct device *dev)
>  {
> -	struct pm_qos_constraints *c = dev->power.constraints;
> -
> -	return c ? pm_qos_read_value(c) : 0;
> +	return dev->power.qos ? pm_qos_read_value(&dev->power.qos->latency) : 0;
>  }
>  
>  /**
> @@ -91,12 +89,12 @@ static int apply_constraint(struct dev_p
>  {
>  	int ret, curr_value;
>  
> -	ret = pm_qos_update_target(req->dev->power.constraints,
> +	ret = pm_qos_update_target(&req->dev->power.qos->latency,
>  				   &req->node, action, value);
>  
>  	if (ret) {
>  		/* Call the global callbacks if needed */
> -		curr_value = pm_qos_read_value(req->dev->power.constraints);
> +		curr_value = pm_qos_read_value(&req->dev->power.qos->latency);
>  		blocking_notifier_call_chain(&dev_pm_notifiers,
>  					     (unsigned long)curr_value,
>  					     req);
> @@ -114,20 +112,22 @@ static int apply_constraint(struct dev_p
>   */
>  static int dev_pm_qos_constraints_allocate(struct device *dev)
>  {
> +	struct dev_pm_qos *qos;
>  	struct pm_qos_constraints *c;
>  	struct blocking_notifier_head *n;
>  
> -	c = kzalloc(sizeof(*c), GFP_KERNEL);
> -	if (!c)
> +	qos = kzalloc(sizeof(*qos), GFP_KERNEL);
> +	if (!qos)
>  		return -ENOMEM;
>  
>  	n = kzalloc(sizeof(*n), GFP_KERNEL);
>  	if (!n) {
> -		kfree(c);
> +		kfree(qos);
>  		return -ENOMEM;
>  	}
>  	BLOCKING_INIT_NOTIFIER_HEAD(n);
>  
> +	c = &qos->latency;
>  	plist_head_init(&c->list);
>  	c->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
>  	c->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
> @@ -135,7 +135,7 @@ static int dev_pm_qos_constraints_alloca
>  	c->notifiers = n;
>  
>  	spin_lock_irq(&dev->power.lock);
> -	dev->power.constraints = c;
> +	dev->power.qos = qos;
>  	spin_unlock_irq(&dev->power.lock);
>  
>  	return 0;
> @@ -151,7 +151,7 @@ static int dev_pm_qos_constraints_alloca
>  void dev_pm_qos_constraints_init(struct device *dev)
>  {
>  	mutex_lock(&dev_pm_qos_mtx);
> -	dev->power.constraints = NULL;
> +	dev->power.qos = NULL;
>  	dev->power.power_state = PMSG_ON;
>  	mutex_unlock(&dev_pm_qos_mtx);
>  }
> @@ -164,6 +164,7 @@ void dev_pm_qos_constraints_init(struct
>   */
>  void dev_pm_qos_constraints_destroy(struct device *dev)
>  {
> +	struct dev_pm_qos *qos;
>  	struct dev_pm_qos_request *req, *tmp;
>  	struct pm_qos_constraints *c;
>  
> @@ -176,10 +177,11 @@ void dev_pm_qos_constraints_destroy(stru
>  	mutex_lock(&dev_pm_qos_mtx);
>  
>  	dev->power.power_state = PMSG_INVALID;
> -	c = dev->power.constraints;
> -	if (!c)
> +	qos = dev->power.qos;
> +	if (!qos)
>  		goto out;
>  
> +	c = &qos->latency;
>  	/* Flush the constraints list for the device */
>  	plist_for_each_entry_safe(req, tmp, &c->list, node) {
>  		/*
> @@ -191,7 +193,7 @@ void dev_pm_qos_constraints_destroy(stru
>  	}
>  
>  	spin_lock_irq(&dev->power.lock);
> -	dev->power.constraints = NULL;
> +	dev->power.qos = NULL;
>  	spin_unlock_irq(&dev->power.lock);
>  
>  	kfree(c->notifiers);
> @@ -235,7 +237,7 @@ int dev_pm_qos_add_request(struct device
>  
>  	mutex_lock(&dev_pm_qos_mtx);
>  
> -	if (!dev->power.constraints) {
> +	if (!dev->power.qos) {
>  		if (dev->power.power_state.event == PM_EVENT_INVALID) {
>  			/* The device has been removed from the system. */
>  			req->dev = NULL;
> @@ -290,7 +292,7 @@ int dev_pm_qos_update_request(struct dev
>  
>  	mutex_lock(&dev_pm_qos_mtx);
>  
> -	if (req->dev->power.constraints) {
> +	if (req->dev->power.qos) {
>  		if (new_value != req->node.prio)
>  			ret = apply_constraint(req, PM_QOS_UPDATE_REQ,
>  					       new_value);
> @@ -329,7 +331,7 @@ int dev_pm_qos_remove_request(struct dev
>  
>  	mutex_lock(&dev_pm_qos_mtx);
>  
> -	if (req->dev->power.constraints) {
> +	if (req->dev->power.qos) {
>  		ret = apply_constraint(req, PM_QOS_REMOVE_REQ,
>  				       PM_QOS_DEFAULT_VALUE);
>  		memset(req, 0, sizeof(*req));
> @@ -362,13 +364,13 @@ int dev_pm_qos_add_notifier(struct devic
>  
>  	mutex_lock(&dev_pm_qos_mtx);
>  
> -	if (!dev->power.constraints)
> +	if (!dev->power.qos)
>  		ret = dev->power.power_state.event != PM_EVENT_INVALID ?
>  			dev_pm_qos_constraints_allocate(dev) : -ENODEV;
>  
>  	if (!ret)
>  		ret = blocking_notifier_chain_register(
> -				dev->power.constraints->notifiers, notifier);
> +				dev->power.qos->latency.notifiers, notifier);
>  
>  	mutex_unlock(&dev_pm_qos_mtx);
>  	return ret;
> @@ -393,9 +395,9 @@ int dev_pm_qos_remove_notifier(struct de
>  	mutex_lock(&dev_pm_qos_mtx);
>  
>  	/* Silently return if the constraints object is not present. */
> -	if (dev->power.constraints)
> +	if (dev->power.qos)
>  		retval = blocking_notifier_chain_unregister(
> -				dev->power.constraints->notifiers,
> +				dev->power.qos->latency.notifiers,
>  				notifier);
>  
>  	mutex_unlock(&dev_pm_qos_mtx);
> 
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