Message-Id: <1395753505-13180-2-git-send-email-amirv@mellanox.com>
Date:	Tue, 25 Mar 2014 15:18:24 +0200
From:	Amir Vadai <amirv@...lanox.com>
To:	"David S. Miller" <davem@...emloft.net>
Cc:	linux-pm@...r.kernel.org, netdev@...r.kernel.org,
	Pavel Machek <pavel@....cz>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, yuvali@...lanox.com,
	Or Gerlitz <ogerlitz@...lanox.com>,
	Yevgeny Petrilin <yevgenyp@...lanox.com>, idos@...lanox.com,
	Amir Vadai <amirv@...lanox.com>
Subject: [RFC 1/2] pm: Introduce QoS requests per CPU

Extend the current pm_qos_request API - to have pm_qos_request per core.
When a global request is added, it is added under the global plist.
When a core specific request is added, it is added to the core specific
list.
core number is saved in the request and later modify/delete operations
are using it to access the right list.

When a cpu specific request is added/removed/updated, the target value
of the specific core is recalculated to be the min/max (according to the
constrain type) value of all the global and the cpu specific
constraints.

If a global request is added/removed/updated, the target values of all
the cpu's are recalculated.

During initialization, before the cpu specific data structures are
allocated and initialized, only global target value is begin used.

Signed-off-by: Ido Shamay <idos@...lanox.com>
Signed-off-by: Amir Vadai <amirv@...lanox.com>
---
 Documentation/trace/events-power.txt |   2 +
 drivers/base/power/qos.c             |   6 +-
 drivers/cpuidle/governors/menu.c     |   2 +-
 include/linux/pm_qos.h               |  22 +++-
 include/trace/events/power.h         |  20 ++--
 kernel/power/qos.c                   | 221 ++++++++++++++++++++++++++---------
 6 files changed, 205 insertions(+), 68 deletions(-)

diff --git a/Documentation/trace/events-power.txt b/Documentation/trace/events-power.txt
index 3bd33b8..be54c6c 100644
--- a/Documentation/trace/events-power.txt
+++ b/Documentation/trace/events-power.txt
@@ -68,6 +68,8 @@ The second parameter is the power domain target state.
 The PM QoS events are used for QoS add/update/remove request and for
 target/flags update.
 
+TODO: update documentation here
+
 pm_qos_add_request                 "pm_qos_class=%s value=%d"
 pm_qos_update_request              "pm_qos_class=%s value=%d"
 pm_qos_remove_request              "pm_qos_class=%s value=%d"
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 5c1361a..d816f00 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -105,7 +105,7 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
 s32 __dev_pm_qos_read_value(struct device *dev)
 {
 	return IS_ERR_OR_NULL(dev->power.qos) ?
-		0 : pm_qos_read_value(&dev->power.qos->latency);
+		0 : pm_qos_read_value(&dev->power.qos->latency, -1);
 }
 
 /**
@@ -143,9 +143,9 @@ static int apply_constraint(struct dev_pm_qos_request *req,
 	switch(req->type) {
 	case DEV_PM_QOS_LATENCY:
 		ret = pm_qos_update_target(&qos->latency, &req->data.pnode,
-					   action, value);
+					   -1, action, value);
 		if (ret) {
-			value = pm_qos_read_value(&qos->latency);
+			value = pm_qos_read_value(&qos->latency, -1);
 			blocking_notifier_call_chain(&dev_pm_notifiers,
 						     (unsigned long)value,
 						     req);
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index cf7f2f0..edb7b4a 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -287,7 +287,7 @@ again:
 static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 {
 	struct menu_device *data = &__get_cpu_var(menu_devices);
-	int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
+	int latency_req = pm_qos_request_cpu(PM_QOS_CPU_DMA_LATENCY, smp_processor_id());
 	int i;
 	int multiplier;
 	struct timespec t;
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 5a95013..62a15ee 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -40,6 +40,7 @@ enum pm_qos_flags_status {
 struct pm_qos_request {
 	struct plist_node node;
 	int pm_qos_class;
+	int cpu;
 	struct delayed_work work; /* for pm_qos_update_request_timeout */
 };
 
@@ -68,6 +69,11 @@ enum pm_qos_type {
 	PM_QOS_MIN		/* return the smallest value */
 };
 
+struct pm_qos_constraints_percpu  {
+	struct plist_head list;
+	s32 target_value;
+};
+
 /*
  * Note: The lockless read path depends on the CPU accessing target_value
  * or effective_flags atomically.  Atomic access is only guaranteed on all CPU
@@ -75,7 +81,11 @@ enum pm_qos_type {
  */
 struct pm_qos_constraints {
 	struct plist_head list;
-	s32 target_value;	/* Do not change to 64 bit */
+	struct pm_qos_constraints_percpu __percpu *percpu;
+	s32 target_value;	/* Do not change to 64 bit.
+				 * Value will be overriden by percpu
+				 * target_value if exists
+				 */
 	s32 default_value;
 	enum pm_qos_type type;
 	struct blocking_notifier_head *notifiers;
@@ -106,12 +116,15 @@ static inline int dev_pm_qos_request_active(struct dev_pm_qos_request *req)
 }
 
 int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
+			 int cpu,
 			 enum pm_qos_req_action action, int value);
 bool pm_qos_update_flags(struct pm_qos_flags *pqf,
 			 struct pm_qos_flags_request *req,
 			 enum pm_qos_req_action action, s32 val);
-void pm_qos_add_request(struct pm_qos_request *req, int pm_qos_class,
-			s32 value);
+void pm_qos_add_request_cpu(struct pm_qos_request *req, int pm_qos_class,
+			    int cpu, s32 value);
+#define pm_qos_add_request(req, pm_qos_class, value) \
+	pm_qos_add_request_cpu(req, pm_qos_class, -1, value)
 void pm_qos_update_request(struct pm_qos_request *req,
 			   s32 new_value);
 void pm_qos_update_request_timeout(struct pm_qos_request *req,
@@ -119,10 +132,11 @@ void pm_qos_update_request_timeout(struct pm_qos_request *req,
 void pm_qos_remove_request(struct pm_qos_request *req);
 
 int pm_qos_request(int pm_qos_class);
+int pm_qos_request_cpu(int pm_qos_class, int cpu);
 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);
-s32 pm_qos_read_value(struct pm_qos_constraints *c);
+s32 pm_qos_read_value(struct pm_qos_constraints *c, int cpu);
 
 #ifdef CONFIG_PM
 enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask);
diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index e5bf9a7..2e441e2 100644
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -340,42 +340,46 @@ TRACE_EVENT(pm_qos_update_request_timeout,
 
 DECLARE_EVENT_CLASS(pm_qos_update,
 
-	TP_PROTO(enum pm_qos_req_action action, int prev_value, int curr_value),
+	TP_PROTO(enum pm_qos_req_action action, int cpu, int prev_value, int curr_value),
 
-	TP_ARGS(action, prev_value, curr_value),
+	TP_ARGS(action, cpu, prev_value, curr_value),
 
 	TP_STRUCT__entry(
 		__field( enum pm_qos_req_action, action         )
+		__field( int,                    cpu            )
 		__field( int,                    prev_value     )
 		__field( int,                    curr_value     )
 	),
 
 	TP_fast_assign(
 		__entry->action = action;
+		__entry->cpu = cpu;
 		__entry->prev_value = prev_value;
 		__entry->curr_value = curr_value;
 	),
 
-	TP_printk("action=%s prev_value=%d curr_value=%d",
+	TP_printk("action=%s cpu=%d prev_value=%d curr_value=%d",
 		  __print_symbolic(__entry->action,
 			{ PM_QOS_ADD_REQ,	"ADD_REQ" },
 			{ PM_QOS_UPDATE_REQ,	"UPDATE_REQ" },
 			{ PM_QOS_REMOVE_REQ,	"REMOVE_REQ" }),
-		  __entry->prev_value, __entry->curr_value)
+		  __entry->cpu, __entry->prev_value, __entry->curr_value)
 );
 
 DEFINE_EVENT(pm_qos_update, pm_qos_update_target,
 
-	TP_PROTO(enum pm_qos_req_action action, int prev_value, int curr_value),
+	TP_PROTO(enum pm_qos_req_action action, int cpu, int prev_value, int
+		 curr_value),
 
-	TP_ARGS(action, prev_value, curr_value)
+	TP_ARGS(action, cpu, prev_value, curr_value)
 );
 
 DEFINE_EVENT_PRINT(pm_qos_update, pm_qos_update_flags,
 
-	TP_PROTO(enum pm_qos_req_action action, int prev_value, int curr_value),
+	TP_PROTO(enum pm_qos_req_action action, int cpu, int prev_value,
+		 int curr_value),
 
-	TP_ARGS(action, prev_value, curr_value),
+	TP_ARGS(action, cpu, prev_value, curr_value),
 
 	TP_printk("action=%s prev_value=0x%x curr_value=0x%x",
 		  __print_symbolic(__entry->action,
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 8dff9b4..4a38329 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -125,59 +125,124 @@ static const struct file_operations pm_qos_power_fops = {
 };
 
 /* unlocked internal variant */
-static inline int pm_qos_get_value(struct pm_qos_constraints *c)
+static inline int pm_qos_get_value(struct pm_qos_constraints *c, int cpu)
 {
-	if (plist_head_empty(&c->list))
+	struct pm_qos_constraints_percpu *cc;
+	struct plist_head *clist = NULL;
+	int val;
+
+	if (c->percpu && cpu >= 0) {
+		cc = per_cpu_ptr(c->percpu, cpu);
+		if (!plist_head_empty(&cc->list))
+			clist= &cc->list;
+	}
+
+	if (plist_head_empty(&c->list) && !clist)
 		return c->default_value;
 
 	switch (c->type) {
 	case PM_QOS_MIN:
-		return plist_first(&c->list)->prio;
-
+		if (plist_head_empty(&c->list))
+			return plist_first(clist)->prio;
+		val = plist_first(&c->list)->prio;
+		if (clist)
+			val = min(val, plist_first(clist)->prio);
+		return val;
 	case PM_QOS_MAX:
-		return plist_last(&c->list)->prio;
-
+		if (plist_head_empty(&c->list))
+			return plist_last(clist)->prio;
+		val = plist_last(&c->list)->prio;
+		if (clist)
+			val = max(val, plist_last(clist)->prio);
+		return val;
 	default:
 		/* runtime check for not using enum */
 		BUG();
-		return PM_QOS_DEFAULT_VALUE;
 	}
+
+	return PM_QOS_DEFAULT_VALUE;
 }
 
-s32 pm_qos_read_value(struct pm_qos_constraints *c)
+s32 pm_qos_read_value(struct pm_qos_constraints *c, int cpu)
 {
+	struct pm_qos_constraints_percpu *cc;
+
+	if (c->percpu && cpu >= 0) {
+		cc = per_cpu_ptr(c->percpu, cpu);
+		return cc->target_value;
+	}
+
 	return c->target_value;
 }
 
-static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
+static inline int _pm_qos_set_value(enum pm_qos_req_action act,
+				    struct pm_qos_constraints *c, int cpu)
 {
+	struct pm_qos_constraints_percpu *cc = per_cpu_ptr(c->percpu, cpu);
+	s32 value = pm_qos_get_value(c, cpu);
+
+	if (value == cc->target_value)
+		return 0;
+
+	trace_pm_qos_update_target(act, cpu, c->target_value, value);
+	cc->target_value = value;
+
+	return 1;
+}
+
+static inline int pm_qos_set_value(enum pm_qos_req_action act,
+				   struct pm_qos_constraints *c, int cpu)
+{
+	s32 value;
+
+	if (cpu >= 0)
+		return _pm_qos_set_value(act, c, cpu);
+
+	value = pm_qos_get_value(c, -1);
+	if (value == c->target_value)
+		return 0;
+
+	trace_pm_qos_update_target(act, -1, c->target_value, value);
 	c->target_value = value;
+
+	if (c->percpu) {
+		for_each_possible_cpu(cpu)
+			_pm_qos_set_value(act, c, cpu);
+	}
+
+	return 1;
 }
 
-/**
- * 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)
+static int _pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
+				 enum pm_qos_req_action action, int value, int cpu)
 {
 	unsigned long flags;
-	int prev_value, curr_value, new_value;
+	int new_value;
+	int ret;
+	struct plist_head *plist;
 
 	spin_lock_irqsave(&pm_qos_lock, flags);
-	prev_value = pm_qos_get_value(c);
 	if (value == PM_QOS_DEFAULT_VALUE)
 		new_value = c->default_value;
 	else
 		new_value = value;
 
+	if (cpu == -1) {
+		plist = &c->list;
+	} else {
+		struct pm_qos_constraints_percpu *cc;
+
+		if (!c->percpu) {
+			ret = 0;
+			printk(KERN_ERR "%s: Can't set cpu constraint\n",
+			       __func__);
+			goto out;
+		}
+
+		cc = per_cpu_ptr(c->percpu, cpu);
+		plist = &cc->list;
+	}
+
 	switch (action) {
 	case PM_QOS_REMOVE_REQ:
 		plist_del(node, &c->list);
@@ -198,20 +263,39 @@ int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
 		;
 	}
 
-	curr_value = pm_qos_get_value(c);
-	pm_qos_set_value(c, curr_value);
+	ret =  pm_qos_set_value(action, c, cpu);
 
+out:
 	spin_unlock_irqrestore(&pm_qos_lock, flags);
 
-	trace_pm_qos_update_target(action, prev_value, curr_value);
-	if (prev_value != curr_value) {
-		blocking_notifier_call_chain(c->notifiers,
-					     (unsigned long)curr_value,
-					     NULL);
-		return 1;
-	} else {
-		return 0;
+	if (ret) {
+		if (c->notifiers)
+			blocking_notifier_call_chain(c->notifiers,
+						     0, /* XXX should change to notifier per core? */
+						     /*(unsigned long)curr_value,*/
+						     NULL);
 	}
+
+	return ret;
+}
+
+/**
+ * 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
+ * @cpu: core number, -1 for all
+ * @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,
+			 int cpu,
+			 enum pm_qos_req_action action, int value)
+{
+	return _pm_qos_update_target(c, node, action, value, -1);
 }
 
 /**
@@ -274,7 +358,7 @@ bool pm_qos_update_flags(struct pm_qos_flags *pqf,
 
 	spin_unlock_irqrestore(&pm_qos_lock, irqflags);
 
-	trace_pm_qos_update_flags(action, prev_value, curr_value);
+	trace_pm_qos_update_flags(action, -1, prev_value, curr_value);
 	return prev_value != curr_value;
 }
 
@@ -286,10 +370,23 @@ bool pm_qos_update_flags(struct pm_qos_flags *pqf,
  */
 int pm_qos_request(int pm_qos_class)
 {
-	return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints);
+	return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints, -1);
 }
 EXPORT_SYMBOL_GPL(pm_qos_request);
 
+/**
+ * pm_qos_request_cpu - returns current per cpu qos expectation
+ * @pm_qos_class: identification of which qos value is requested
+ * @cpu: core number
+ *
+ * This function returns the current target value for a core.
+ */
+int pm_qos_request_cpu(int pm_qos_class, int cpu)
+{
+	return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints, cpu);
+}
+EXPORT_SYMBOL_GPL(pm_qos_request_cpu);
+
 int pm_qos_request_active(struct pm_qos_request *req)
 {
 	return req->pm_qos_class != 0;
@@ -297,14 +394,14 @@ int pm_qos_request_active(struct pm_qos_request *req)
 EXPORT_SYMBOL_GPL(pm_qos_request_active);
 
 static void __pm_qos_update_request(struct pm_qos_request *req,
-			   s32 new_value)
+				    s32 new_value)
 {
 	trace_pm_qos_update_request(req->pm_qos_class, new_value);
 
 	if (new_value != req->node.prio)
 		pm_qos_update_target(
 			pm_qos_array[req->pm_qos_class]->constraints,
-			&req->node, PM_QOS_UPDATE_REQ, new_value);
+			&req->node, req->cpu, PM_QOS_UPDATE_REQ, new_value);
 }
 
 /**
@@ -326,6 +423,7 @@ static void pm_qos_work_fn(struct work_struct *work)
  * pm_qos_add_request - inserts new qos request into the list
  * @req: pointer to a preallocated handle
  * @pm_qos_class: identifies which list of qos request to use
+ * @cpu : cpu which the request belong to. -1 for global request
  * @value: defines the qos request
  *
  * This function inserts a new entry in the pm_qos_class list of requested qos
@@ -334,9 +432,8 @@ static void pm_qos_work_fn(struct work_struct *work)
  * handle.  Caller needs to save this handle for later use in updates and
  * removal.
  */
-
-void pm_qos_add_request(struct pm_qos_request *req,
-			int pm_qos_class, s32 value)
+void pm_qos_add_request_cpu(struct pm_qos_request *req,
+			    int pm_qos_class, int cpu, s32 value)
 {
 	if (!req) /*guard against callers passing in null */
 		return;
@@ -346,12 +443,13 @@ void pm_qos_add_request(struct pm_qos_request *req,
 		return;
 	}
 	req->pm_qos_class = pm_qos_class;
+	req->cpu = cpu;
 	INIT_DELAYED_WORK(&req->work, pm_qos_work_fn);
 	trace_pm_qos_add_request(pm_qos_class, value);
 	pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints,
-			     &req->node, PM_QOS_ADD_REQ, value);
+			     &req->node, cpu, PM_QOS_ADD_REQ, value);
 }
-EXPORT_SYMBOL_GPL(pm_qos_add_request);
+EXPORT_SYMBOL_GPL(pm_qos_add_request_cpu);
 
 /**
  * pm_qos_update_request - modifies an existing qos request
@@ -364,7 +462,7 @@ EXPORT_SYMBOL_GPL(pm_qos_add_request);
  * Attempts are made to make this code callable on hot code paths.
  */
 void pm_qos_update_request(struct pm_qos_request *req,
-			   s32 new_value)
+			       s32 new_value)
 {
 	if (!req) /*guard against callers passing in null */
 		return;
@@ -387,8 +485,8 @@ EXPORT_SYMBOL_GPL(pm_qos_update_request);
  *
  * After timeout_us, this qos request is cancelled automatically.
  */
-void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value,
-				   unsigned long timeout_us)
+void pm_qos_update_request_timeout(struct pm_qos_request *req,
+				   s32 new_value, unsigned long timeout_us)
 {
 	if (!req)
 		return;
@@ -403,7 +501,7 @@ void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value,
 	if (new_value != req->node.prio)
 		pm_qos_update_target(
 			pm_qos_array[req->pm_qos_class]->constraints,
-			&req->node, PM_QOS_UPDATE_REQ, new_value);
+			&req->node, req->cpu, PM_QOS_UPDATE_REQ, new_value);
 
 	schedule_delayed_work(&req->work, usecs_to_jiffies(timeout_us));
 }
@@ -431,7 +529,7 @@ void pm_qos_remove_request(struct pm_qos_request *req)
 
 	trace_pm_qos_remove_request(req->pm_qos_class, PM_QOS_DEFAULT_VALUE);
 	pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints,
-			     &req->node, PM_QOS_REMOVE_REQ,
+			     &req->node, req->cpu, PM_QOS_REMOVE_REQ,
 			     PM_QOS_DEFAULT_VALUE);
 	memset(req, 0, sizeof(*req));
 }
@@ -529,7 +627,7 @@ static int pm_qos_power_release(struct inode *inode, struct file *filp)
 	return 0;
 }
 
-
+// TODO sysfs for non global
 static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
 		size_t count, loff_t *f_pos)
 {
@@ -543,7 +641,7 @@ static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
 		return -EINVAL;
 
 	spin_lock_irqsave(&pm_qos_lock, flags);
-	value = pm_qos_get_value(pm_qos_array[req->pm_qos_class]->constraints);
+	value = pm_qos_get_value(pm_qos_array[req->pm_qos_class]->constraints, -1);
 	spin_unlock_irqrestore(&pm_qos_lock, flags);
 
 	return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
@@ -581,10 +679,29 @@ static int __init pm_qos_power_init(void)
 	BUILD_BUG_ON(ARRAY_SIZE(pm_qos_array) != PM_QOS_NUM_CLASSES);
 
 	for (i = PM_QOS_CPU_DMA_LATENCY; i < PM_QOS_NUM_CLASSES; i++) {
-		ret = register_pm_qos_misc(pm_qos_array[i]);
+		struct pm_qos_object *pm_qos = pm_qos_array[i];
+		struct pm_qos_constraints *c = pm_qos->constraints;
+
+		c->percpu = alloc_percpu(struct pm_qos_constraints_percpu);
+		if (!c->percpu) {
+			printk(KERN_ERR "pm_qos_param: %s per cpu alloc failed\n",
+			       pm_qos->name);
+		} else {
+			int cpu;
+
+			for_each_possible_cpu(cpu) {
+				struct pm_qos_constraints_percpu *cc =
+					per_cpu_ptr(c->percpu, cpu);
+
+				plist_head_init(&cc->list);
+				cc->target_value = pm_qos_read_value(c, -1);
+			}
+		}
+
+		ret = register_pm_qos_misc(pm_qos);
 		if (ret < 0) {
 			printk(KERN_ERR "pm_qos_param: %s setup failed\n",
-			       pm_qos_array[i]->name);
+			       pm_qos->name);
 			return ret;
 		}
 	}
-- 
1.8.3.4

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