On Saturday, August 13, 2011, mark gross wrote:
> On Thu, Aug 11, 2011 at 05:06:42PM +0200, jean.pihet@xxxxxxxxxxxxxx wrote:
> > From: Jean Pihet <j-pihet@xxxxxx>
> >
> > In preparation for the per-device constratins support:
> > - rename update_target to pm_qos_update_target
> > - generalize and export pm_qos_update_target for usage by the upcoming
> > per-device latency constraints framework:
> > . operate on struct pm_qos_constraints for constraints management,
> > . introduce an 'action' parameter for constraints add/update/remove,
> > . the return value indicates if the aggregated constraint value has
> > changed,
> > - update the internal code to operate on struct pm_qos_constraints
> > - add a NULL pointer check in the API functions
> >
> > Signed-off-by: Jean Pihet <j-pihet@xxxxxx>
> >
> > ---
> > include/linux/pm_qos.h | 14 ++++++
> > kernel/power/qos.c | 123 ++++++++++++++++++++++++++----------------------
> > 2 files changed, 81 insertions(+), 56 deletions(-)
> >
> > diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
> > index 9772311..84aa150 100644
> > --- a/include/linux/pm_qos.h
> > +++ b/include/linux/pm_qos.h
> > @@ -44,7 +44,16 @@ struct pm_qos_constraints {
> > struct blocking_notifier_head *notifiers;
> > };
> >
> > +/* Action requested to pm_qos_update_target */
> > +enum pm_qos_req_action {
> > + PM_QOS_ADD_REQ, /* Add a new request */
> > + PM_QOS_UPDATE_REQ, /* Update an existing request */
> > + PM_QOS_REMOVE_REQ /* Remove an existing request */
> > +};
> > +
>
> What do you need this enum for? The function names *_update_*, *_add_*,
> and *_remove_* seem to be pretty redundant if you have to pass an enum
> that could possibly conflict with the function name.
>
> > #ifdef CONFIG_PM
> > +int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
> > + enum pm_qos_req_action action, int value);
> The action for update_target better damn well be "PM_QOS_UPDATE_REQ" or
> there is something strange going on.... BTW what shold this function do
> if the pm_qos_req_action was *not* the UPDATE one?
>
>
> pm_qos_update_target should be a static to the C- file along with the
> enum pm_qos_req_action.
>
>
> > void pm_qos_add_request(struct pm_qos_request *req, int pm_qos_class,
> > s32 value);
> > void pm_qos_update_request(struct pm_qos_request *req,
> > @@ -56,6 +65,11 @@ int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
> > int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
> > int pm_qos_request_active(struct pm_qos_request *req);
> > #else
> > +static inline int pm_qos_update_target(struct pm_qos_constraints *c,
> > + struct plist_node *node,
> > + enum pm_qos_req_action action,
> > + int value)
> > + { return 0; }
> > static inline void pm_qos_add_request(struct pm_qos_request *req,
> > int pm_qos_class, s32 value)
> > { return; }
> > diff --git a/kernel/power/qos.c b/kernel/power/qos.c
> > index 66e8d6f..fc60f96 100644
> > --- a/kernel/power/qos.c
> > +++ b/kernel/power/qos.c
> > @@ -121,17 +121,17 @@ static const struct file_operations pm_qos_power_fops = {
> > };
> >
> > /* unlocked internal variant */
> > -static inline int pm_qos_get_value(struct pm_qos_object *o)
> > +static inline int pm_qos_get_value(struct pm_qos_constraints *c)
> > {
> > - if (plist_head_empty(&o->constraints->list))
> > - return o->constraints->default_value;
> > + if (plist_head_empty(&c->list))
> > + return c->default_value;
> >
> > - switch (o->constraints->type) {
> > + switch (c->type) {
> > case PM_QOS_MIN:
> > - return plist_first(&o->constraints->list)->prio;
> > + return plist_first(&c->list)->prio;
> >
> > case PM_QOS_MAX:
> > - return plist_last(&o->constraints->list)->prio;
> > + return plist_last(&c->list)->prio;
> >
> > default:
> > /* runtime check for not using enum */
> > @@ -139,47 +139,73 @@ static inline int pm_qos_get_value(struct pm_qos_object *o)
> > }
> > }
> >
> > -static inline s32 pm_qos_read_value(struct pm_qos_object *o)
> > +static inline s32 pm_qos_read_value(struct pm_qos_constraints *c)
> > {
> > - return o->constraints->target_value;
> > + return c->target_value;
> > }
> >
> > -static inline void pm_qos_set_value(struct pm_qos_object *o, s32 value)
> > +static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
> > {
> > - o->constraints->target_value = value;
> > + c->target_value = value;
> > }
> >
> > -static void update_target(struct pm_qos_object *o, struct plist_node *node,
> > - int del, int value)
> > +/**
> > + * pm_qos_update_target - manages the constraints list and calls the notifiers
> > + * if needed
> > + * @c: constraints data struct
> > + * @node: request to add to the list, to update or to remove
> > + * @action: action to take on the constraints list
> > + * @value: value of the request to add or update
> > + *
> > + * This function returns 1 if the aggregated constraint value has changed, 0
> > + * otherwise.
> > + */
> > +int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
> > + enum pm_qos_req_action action, int value)
> > {
> > unsigned long flags;
> > - int prev_value, curr_value;
> > + int prev_value, curr_value, new_value;
> >
> > spin_lock_irqsave(&pm_qos_lock, flags);
> > - prev_value = pm_qos_get_value(o);
> > - /* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */
> > - if (value != PM_QOS_DEFAULT_VALUE) {
> > + prev_value = pm_qos_get_value(c);
> > + if (value == PM_QOS_DEFAULT_VALUE)
> > + new_value = c->default_value;
> > + else
> > + new_value = value;
> > +
> > + switch (action) {
> > + case PM_QOS_REMOVE_REQ:
> We have a remove request API already. This overloading of this
> interface feels wrong to me.
>
> > + plist_del(node, &c->list);
> > + break;
> > + case PM_QOS_UPDATE_REQ:
> > /*
> > * to change the list, we atomically remove, reinit
> > * with new value and add, then see if the extremal
> > * changed
> > */
> > - plist_del(node, &o->constraints->list);
> > - plist_node_init(node, value);
> > - plist_add(node, &o->constraints->list);
> > - } else if (del) {
> > - plist_del(node, &o->constraints->list);
> > - } else {
> > - plist_add(node, &o->constraints->list);
> > + plist_del(node, &c->list);
> > + case PM_QOS_ADD_REQ:
> Don't we have an API for adding a request? if you want to overload
> update like this then either we lose the add API or this shouldn't be
> here.
>
>
> > + plist_node_init(node, new_value);
> > + plist_add(node, &c->list);
> > + break;
> > + default:
> > + /* no action */
> > + ;
> > }
> > - curr_value = pm_qos_get_value(o);
> > - pm_qos_set_value(o, curr_value);
> > +
> > + curr_value = pm_qos_get_value(c);
> > + pm_qos_set_value(c, curr_value);
> > +
> > spin_unlock_irqrestore(&pm_qos_lock, flags);
> >
> > - if (prev_value != curr_value)
> > - blocking_notifier_call_chain(o->constraints->notifiers,
> > + if (prev_value != curr_value) {
> > + blocking_notifier_call_chain(c->notifiers,
> > (unsigned long)curr_value,
> > NULL);
> > + return 1;
> > + } else {
> > + return 0;
> > + }
> > }
> >
> > /**
> > @@ -190,7 +216,7 @@ static void update_target(struct pm_qos_object *o, struct plist_node *node,
> > */
> > int pm_qos_request(int pm_qos_class)
> > {
> > - return pm_qos_read_value(pm_qos_array[pm_qos_class]);
> > + return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints);
> > }
> > EXPORT_SYMBOL_GPL(pm_qos_request);
> >
> > @@ -216,20 +242,16 @@ EXPORT_SYMBOL_GPL(pm_qos_request_active);
> > void pm_qos_add_request(struct pm_qos_request *req,
> > int pm_qos_class, s32 value)
> > {
> > - struct pm_qos_object *o = pm_qos_array[pm_qos_class];
> > - int new_value;
> > + if (!req) /*guard against callers passing in null */
> > + return;
> >
> > if (pm_qos_request_active(req)) {
> > WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");
> > return;
> > }
> > - if (value == PM_QOS_DEFAULT_VALUE)
> > - new_value = o->constraints->default_value;
> > - else
> > - new_value = value;
> > - plist_node_init(&req->node, new_value);
> > req->pm_qos_class = pm_qos_class;
> > - update_target(o, &req->node, 0, PM_QOS_DEFAULT_VALUE);
> > + pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints,
> > + &req->node, PM_QOS_ADD_REQ, value);
>
> Ok, using pm_qos_update_target to reduce the LOC is ok but I don't think
> this function and the enum should be exported outside of pm_qos.c
They are used by the next patches adding the per-device QoS.
Thanks,
Rafael
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