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cpuidle: Single/Global registration of idle states

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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>
This commit is contained in:
Deepthi Dharwar
2011-10-28 16:20:42 +05:30
committed by Len Brown
parent 4202735e8a
commit 46bcfad7a8
16 changed files with 438 additions and 206 deletions
Download Patch File Download Diff File Expand all files Collapse all files

191
drivers/acpi/processor_idle.c
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@@ -741,11 +741,13 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx)
/**
* 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 @@ static int acpi_idle_enter_c1(struct cpuidle_device *dev, int index)
/**
* 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 @@ static DEFINE_SPINLOCK(c3_lock);
/**
* 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 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev, int index)
}
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 @@ struct cpuidle_driver acpi_idle_driver = {
};
/**
* 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 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
}
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 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
!(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 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
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 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
break;
}
dev->state_count = count;
drv->state_count = count;
if (!count)
return -EINVAL;
@@ -1079,7 +1136,7 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
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 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
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 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
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 @@ int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
* 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 @@ int acpi_processor_power_exit(struct acpi_processor *pr,
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;
}