cpuidle: Single/Global registration of idle states
This patch makes the cpuidle_states structure global (single copy)
instead of per-cpu. The statistics needed on per-cpu basis
by the governor are kept per-cpu. This simplifies the cpuidle
subsystem as state registration is done by single cpu only.
Having single copy of cpuidle_states saves memory. Rare case
of asymmetric C-states can be handled within the cpuidle driver
and architectures such as POWER do not have asymmetric C-states.
Having single/global registration of all the idle states,
dynamic C-state transitions on x86 are handled by
the boot cpu. Here, the boot cpu would disable all the devices,
re-populate the states and later enable all the devices,
irrespective of the cpu that would receive the notification first.
Reference:
https://lkml.org/lkml/2011/4/25/83
Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index b98c752..24fe3af 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -741,11 +741,13 @@
/**
* acpi_idle_enter_c1 - enters an ACPI C1 state-type
* @dev: the target CPU
+ * @drv: cpuidle driver containing cpuidle state info
* @index: index of target state
*
* This is equivalent to the HALT instruction.
*/
-static int acpi_idle_enter_c1(struct cpuidle_device *dev, int index)
+static int acpi_idle_enter_c1(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv, int index)
{
ktime_t kt1, kt2;
s64 idle_time;
@@ -787,9 +789,11 @@
/**
* acpi_idle_enter_simple - enters an ACPI state without BM handling
* @dev: the target CPU
+ * @drv: cpuidle driver with cpuidle state information
* @index: the index of suggested state
*/
-static int acpi_idle_enter_simple(struct cpuidle_device *dev, int index)
+static int acpi_idle_enter_simple(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv, int index)
{
struct acpi_processor *pr;
struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
@@ -869,11 +873,13 @@
/**
* acpi_idle_enter_bm - enters C3 with proper BM handling
* @dev: the target CPU
+ * @drv: cpuidle driver containing state data
* @index: the index of suggested state
*
* If BM is detected, the deepest non-C3 idle state is entered instead.
*/
-static int acpi_idle_enter_bm(struct cpuidle_device *dev, int index)
+static int acpi_idle_enter_bm(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv, int index)
{
struct acpi_processor *pr;
struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
@@ -896,9 +902,9 @@
}
if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
- if (dev->safe_state_index >= 0) {
- return dev->states[dev->safe_state_index].enter(dev,
- dev->safe_state_index);
+ if (drv->safe_state_index >= 0) {
+ return drv->states[drv->safe_state_index].enter(dev,
+ drv, drv->safe_state_index);
} else {
local_irq_disable();
acpi_safe_halt();
@@ -993,14 +999,15 @@
};
/**
- * acpi_processor_setup_cpuidle - prepares and configures CPUIDLE
+ * acpi_processor_setup_cpuidle_cx - prepares and configures CPUIDLE
+ * device i.e. per-cpu data
+ *
* @pr: the ACPI processor
*/
-static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
+static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr)
{
int i, count = CPUIDLE_DRIVER_STATE_START;
struct acpi_processor_cx *cx;
- struct cpuidle_state *state;
struct cpuidle_state_usage *state_usage;
struct cpuidle_device *dev = &pr->power.dev;
@@ -1012,18 +1019,12 @@
}
dev->cpu = pr->id;
- dev->safe_state_index = -1;
- for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
- dev->states[i].name[0] = '\0';
- dev->states[i].desc[0] = '\0';
- }
if (max_cstate == 0)
max_cstate = 1;
for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
cx = &pr->power.states[i];
- state = &dev->states[count];
state_usage = &dev->states_usage[count];
if (!cx->valid)
@@ -1035,8 +1036,64 @@
!(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
continue;
#endif
+
cpuidle_set_statedata(state_usage, cx);
+ count++;
+ if (count == CPUIDLE_STATE_MAX)
+ break;
+ }
+
+ dev->state_count = count;
+
+ if (!count)
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
+ * acpi_processor_setup_cpuidle states- prepares and configures cpuidle
+ * global state data i.e. idle routines
+ *
+ * @pr: the ACPI processor
+ */
+static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+{
+ int i, count = CPUIDLE_DRIVER_STATE_START;
+ struct acpi_processor_cx *cx;
+ struct cpuidle_state *state;
+ struct cpuidle_driver *drv = &acpi_idle_driver;
+
+ if (!pr->flags.power_setup_done)
+ return -EINVAL;
+
+ if (pr->flags.power == 0)
+ return -EINVAL;
+
+ drv->safe_state_index = -1;
+ for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
+ drv->states[i].name[0] = '\0';
+ drv->states[i].desc[0] = '\0';
+ }
+
+ if (max_cstate == 0)
+ max_cstate = 1;
+
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
+ cx = &pr->power.states[i];
+
+ if (!cx->valid)
+ continue;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst &&
+ !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
+ continue;
+#endif
+
+ state = &drv->states[count];
snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
strncpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
state->exit_latency = cx->latency;
@@ -1049,13 +1106,13 @@
state->flags |= CPUIDLE_FLAG_TIME_VALID;
state->enter = acpi_idle_enter_c1;
- dev->safe_state_index = count;
+ drv->safe_state_index = count;
break;
case ACPI_STATE_C2:
state->flags |= CPUIDLE_FLAG_TIME_VALID;
state->enter = acpi_idle_enter_simple;
- dev->safe_state_index = count;
+ drv->safe_state_index = count;
break;
case ACPI_STATE_C3:
@@ -1071,7 +1128,7 @@
break;
}
- dev->state_count = count;
+ drv->state_count = count;
if (!count)
return -EINVAL;
@@ -1079,7 +1136,7 @@
return 0;
}
-int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+int acpi_processor_hotplug(struct acpi_processor *pr)
{
int ret = 0;
@@ -1100,7 +1157,7 @@
cpuidle_disable_device(&pr->power.dev);
acpi_processor_get_power_info(pr);
if (pr->flags.power) {
- acpi_processor_setup_cpuidle(pr);
+ acpi_processor_setup_cpuidle_cx(pr);
ret = cpuidle_enable_device(&pr->power.dev);
}
cpuidle_resume_and_unlock();
@@ -1108,10 +1165,72 @@
return ret;
}
+int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+{
+ int cpu;
+ struct acpi_processor *_pr;
+
+ if (disabled_by_idle_boot_param())
+ return 0;
+
+ if (!pr)
+ return -EINVAL;
+
+ if (nocst)
+ return -ENODEV;
+
+ if (!pr->flags.power_setup_done)
+ return -ENODEV;
+
+ /*
+ * FIXME: Design the ACPI notification to make it once per
+ * system instead of once per-cpu. This condition is a hack
+ * to make the code that updates C-States be called once.
+ */
+
+ if (smp_processor_id() == 0 &&
+ cpuidle_get_driver() == &acpi_idle_driver) {
+
+ cpuidle_pause_and_lock();
+ /* Protect against cpu-hotplug */
+ get_online_cpus();
+
+ /* Disable all cpuidle devices */
+ for_each_online_cpu(cpu) {
+ _pr = per_cpu(processors, cpu);
+ if (!_pr || !_pr->flags.power_setup_done)
+ continue;
+ cpuidle_disable_device(&_pr->power.dev);
+ }
+
+ /* Populate Updated C-state information */
+ acpi_processor_setup_cpuidle_states(pr);
+
+ /* Enable all cpuidle devices */
+ for_each_online_cpu(cpu) {
+ _pr = per_cpu(processors, cpu);
+ if (!_pr || !_pr->flags.power_setup_done)
+ continue;
+ acpi_processor_get_power_info(_pr);
+ if (_pr->flags.power) {
+ acpi_processor_setup_cpuidle_cx(_pr);
+ cpuidle_enable_device(&_pr->power.dev);
+ }
+ }
+ put_online_cpus();
+ cpuidle_resume_and_unlock();
+ }
+
+ return 0;
+}
+
+static int acpi_processor_registered;
+
int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
struct acpi_device *device)
{
acpi_status status = 0;
+ int retval;
static int first_run;
if (disabled_by_idle_boot_param())
@@ -1148,9 +1267,26 @@
* platforms that only support C1.
*/
if (pr->flags.power) {
- acpi_processor_setup_cpuidle(pr);
- if (cpuidle_register_device(&pr->power.dev))
- return -EIO;
+ /* Register acpi_idle_driver if not already registered */
+ if (!acpi_processor_registered) {
+ acpi_processor_setup_cpuidle_states(pr);
+ retval = cpuidle_register_driver(&acpi_idle_driver);
+ if (retval)
+ return retval;
+ printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n",
+ acpi_idle_driver.name);
+ }
+ /* Register per-cpu cpuidle_device. Cpuidle driver
+ * must already be registered before registering device
+ */
+ acpi_processor_setup_cpuidle_cx(pr);
+ retval = cpuidle_register_device(&pr->power.dev);
+ if (retval) {
+ if (acpi_processor_registered == 0)
+ cpuidle_unregister_driver(&acpi_idle_driver);
+ return retval;
+ }
+ acpi_processor_registered++;
}
return 0;
}
@@ -1161,8 +1297,13 @@
if (disabled_by_idle_boot_param())
return 0;
- cpuidle_unregister_device(&pr->power.dev);
- pr->flags.power_setup_done = 0;
+ if (pr->flags.power) {
+ cpuidle_unregister_device(&pr->power.dev);
+ acpi_processor_registered--;
+ if (acpi_processor_registered == 0)
+ cpuidle_unregister_driver(&acpi_idle_driver);
+ }
+ pr->flags.power_setup_done = 0;
return 0;
}