[Dynamicpower-devel] DPM constraints speedup

[Todd P. <tp...@mv...>]

In case anyone is interested, a patch to speed up searching for device
constraints by placing these in their own list (instead of traversing
full LDM lists).  This also removes the last traces of the in-kernel
forced operating point code, which is now relegated to userspace.  Planned
for the next rev of DPM, comments appreciated.  Thanks -- Todd

Index: linux-2.6.10/drivers/base/power/power-dpm.c
===================================================================
--- linux-2.6.10.orig/drivers/base/power/power-dpm.c	2005-03-03 01:01:59.000000000 +0000
+++ linux-2.6.10/drivers/base/power/power-dpm.c	2005-03-03 03:21:30.000000000 +0000
@@ -17,10 +17,6 @@
 
 #include "power.h"
 
-/* Hack: Special values for power_state */
-
-#define DPM_STATE_CONSTRAINED 100
-
 #ifdef CONFIG_HOTPLUG
 /*
  * power hotplug events
@@ -160,13 +156,19 @@
  */
 
 
+LIST_HEAD(dpm_constraints);
+DECLARE_MUTEX(dpm_constraints_sem);
+
 void assert_constraints(struct constraints *constraints)
 {
 #ifdef CONFIG_DPM
 	if (! constraints || constraints->asserted)
 		return;
 
+	down(&dpm_constraints_sem);
 	constraints->asserted = 1;
+	list_add_tail(&constraints->entry, &dpm_constraints);
+	up(&dpm_constraints_sem);
 
 	/* DPM-PM-TODO: Check against DPM state. */
 
@@ -180,7 +182,10 @@
 	if (! constraints || ! constraints->asserted)
 		return;
 
+	down(&dpm_constraints_sem);
 	constraints->asserted = 0;
+	list_del_init(&constraints->entry);
+	up(&dpm_constraints_sem);
 #endif /* CONFIG_DPM */
 }
 
@@ -226,17 +231,13 @@
 	int provisional = 0;
 	int ret = 0;
 
-	if(!dev->constraints) {
+	if (!dev->constraints) {
 		if (! (dev->constraints = kmalloc(sizeof(struct constraints),
 						  GFP_KERNEL)))
 			return -EINVAL;
 
 		memset(dev->constraints, 0, 
 		       sizeof(struct constraints));
-
-		/* New constraints should start off with same state as power
-		   state */
-		dev->constraints->asserted = dev->power.power_state ? 0 : 1;
 		provisional = 1;
 	}
 
@@ -285,6 +286,11 @@
 	if (cidx == dev->constraints->count)
 		dev->constraints->count++;
 
+	/* New constraints should start off with same state as power
+	   state */
+	if (provisional && (dev->power.power_state == 0))
+		assert_constraints(dev->constraints);
+
 out:
 
 	if (provisional && (ret < 0)) {
@@ -334,13 +340,6 @@
 int dpm_constraint_rejects = 0;
 
 
-#if 0 // move-force-to-userspace
-static void dpm_suspend_for_opt(struct device * dev)
-{
-	suspend_device(dev, DPM_STATE_CONSTRAINED);
-}
-#endif // move-force-to-userspace
-
 int
 dpm_default_check_constraint(struct constraint_param *param, 
 			     struct dpm_opt *opt)
@@ -379,38 +378,19 @@
 	struct list_head * entry;
 	int valid = 1;
 
-	list_for_each_prev(entry,&dpm_active) {
-		struct device * dev = to_device(entry);
-
-		if (!dpm_check_a_constraint(dev->constraints, opt)) {
-			dev->constraints->violations++;
+	list_for_each(entry,&dpm_constraints) {
+		struct constraints *constraints = 
+			list_entry(entry, struct constraints, entry);
+		if (!dpm_check_a_constraint(constraints, opt)) {
+			constraints->violations++;
 			dpm_constraint_rejects++;
-#if 0 // move-force-to-userspace
-			if (opt->force)
-				dpm_suspend_for_opt(dev);
-			else
-#endif // move-force-to-userspace
-				valid = 0;
+			valid = 0;
 		}
 	}
 
 	return valid;
 }
 
-void dpm_recheck_constraints(struct dpm_opt *opt)
-{
-	struct list_head * entry;
-
-	list_for_each_prev(entry,&dpm_active) {
-		struct device * dev = to_device(entry);
-
-		if (dev->power.power_state == DPM_STATE_CONSTRAINED) {
-			if (dpm_check_a_constraint(dev->constraints, opt))
-				resume_device(dev);
-		}
-	}
-}
-
 int dpm_show_opconstraints(struct dpm_opt *opt, char * buf)
 {
 	struct list_head * entry;
Index: linux-2.6.10/drivers/dpm/dpm.c
===================================================================
--- linux-2.6.10.orig/drivers/dpm/dpm.c	2005-03-03 01:02:01.000000000 +0000
+++ linux-2.6.10/drivers/dpm/dpm.c	2005-03-03 02:34:32.000000000 +0000
@@ -282,10 +282,6 @@
 int
 dpm_set_opt(struct dpm_opt *new, unsigned flags)
 {
-#if 0 // move-force-to-userspace
-	struct dpm_opt *old_opt = dpm_active_opt;
-#endif // move-force-to-userspace
-
 	if (new->flags & DPM_OP_NOP) {
 		if (flags & DPM_UNLOCK)
 			dpm_unlock();
@@ -311,7 +307,7 @@
 
 	/*
 	 * Remove the IRQ disable since in some cases scheduling is needed
-	 * to set an operating point (sleep or force mode).  The spinlock
+	 * to set an operating point (only sleep mode).  The spinlock
 	 * should suffice.  If the machine-dependent code needs interrupts
 	 * turned off during the code used for that platform for that 
 	 * operating point set sequence then IRQs will need to be disabled
@@ -327,16 +323,6 @@
 	if (flags & DPM_UNLOCK)
 		dpm_unlock();
 
-#if 0 // move-force-to-userspace
-	/*
-	 * If transitioning away from a forced operating point, see if
-	 * any devices forced off can be resumed.
-	 */	    
-
-	if (old_opt && old_opt->force)
-		dpm_recheck_constraints(new);
-#endif // move-force-to-userspace
-
 	return 0;
 }
 
Index: linux-2.6.10/include/linux/pm.h
===================================================================
--- linux-2.6.10.orig/include/linux/pm.h	2005-03-03 01:02:01.000000000 +0000
+++ linux-2.6.10/include/linux/pm.h	2005-03-03 01:48:18.000000000 +0000
@@ -270,6 +270,7 @@
 	int count;
 	int violations;
 	struct constraint_param param[DPM_CONSTRAINT_PARAMS_MAX];
+	struct list_head entry;
 };
 
 enum {