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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-08-24 00:19:57 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-08-30 04:05:29 +0300
commitdc2251bf98c66db3f4e055b751968f0871037ae4 (patch)
treea18ffbaae6dc1e54069fd19ebcfc93b88d42a9fa /drivers/cpuidle
parent84dc4141f0353bada6af53d32730f3e47e579bc0 (diff)
downloadlinux-dc2251bf98c66db3f4e055b751968f0871037ae4.tar.xz
cpuidle: Eliminate the CPUIDLE_DRIVER_STATE_START symbol
On some architectures the first (index 0) idle state is a polling one and it doesn't really save energy, so there is the CPUIDLE_DRIVER_STATE_START symbol allowing some pieces of cpuidle code to avoid using that state. However, this makes the code rather hard to follow. It is better to explicitly avoid the polling state, so add a new cpuidle state flag CPUIDLE_FLAG_POLLING to mark it and make the relevant code check that flag for the first state instead of using the CPUIDLE_DRIVER_STATE_START symbol. In the ACPI processor driver that cannot always rely on the state flags (like before the states table has been set up) define a new internal symbol ACPI_IDLE_STATE_START equivalent to the CPUIDLE_DRIVER_STATE_START one and drop the latter. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/driver.c1
-rw-r--r--drivers/cpuidle/governors/ladder.c14
-rw-r--r--drivers/cpuidle/governors/menu.c13
3 files changed, 14 insertions, 14 deletions
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index e53fb861beb0..e942f8ef4309 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -204,6 +204,7 @@ static void poll_idle_init(struct cpuidle_driver *drv)
state->power_usage = -1;
state->enter = poll_idle;
state->disabled = false;
+ state->flags = CPUIDLE_FLAG_POLLING;
}
#else
static void poll_idle_init(struct cpuidle_driver *drv) {}
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index ac321f09e717..ce1a2ffffb2a 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -69,6 +69,7 @@ static int ladder_select_state(struct cpuidle_driver *drv,
struct ladder_device *ldev = this_cpu_ptr(&ladder_devices);
struct ladder_device_state *last_state;
int last_residency, last_idx = ldev->last_state_idx;
+ int first_idx = drv->states[0].flags & CPUIDLE_FLAG_POLLING ? 1 : 0;
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
/* Special case when user has set very strict latency requirement */
@@ -96,13 +97,13 @@ static int ladder_select_state(struct cpuidle_driver *drv,
}
/* consider demotion */
- if (last_idx > CPUIDLE_DRIVER_STATE_START &&
+ if (last_idx > first_idx &&
(drv->states[last_idx].disabled ||
dev->states_usage[last_idx].disable ||
drv->states[last_idx].exit_latency > latency_req)) {
int i;
- for (i = last_idx - 1; i > CPUIDLE_DRIVER_STATE_START; i--) {
+ for (i = last_idx - 1; i > first_idx; i--) {
if (drv->states[i].exit_latency <= latency_req)
break;
}
@@ -110,7 +111,7 @@ static int ladder_select_state(struct cpuidle_driver *drv,
return i;
}
- if (last_idx > CPUIDLE_DRIVER_STATE_START &&
+ if (last_idx > first_idx &&
last_residency < last_state->threshold.demotion_time) {
last_state->stats.demotion_count++;
last_state->stats.promotion_count = 0;
@@ -133,13 +134,14 @@ static int ladder_enable_device(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{
int i;
+ int first_idx = drv->states[0].flags & CPUIDLE_FLAG_POLLING ? 1 : 0;
struct ladder_device *ldev = &per_cpu(ladder_devices, dev->cpu);
struct ladder_device_state *lstate;
struct cpuidle_state *state;
- ldev->last_state_idx = CPUIDLE_DRIVER_STATE_START;
+ ldev->last_state_idx = first_idx;
- for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+ for (i = first_idx; i < drv->state_count; i++) {
state = &drv->states[i];
lstate = &ldev->states[i];
@@ -151,7 +153,7 @@ static int ladder_enable_device(struct cpuidle_driver *drv,
if (i < drv->state_count - 1)
lstate->threshold.promotion_time = state->exit_latency;
- if (i > CPUIDLE_DRIVER_STATE_START)
+ if (i > first_idx)
lstate->threshold.demotion_time = state->exit_latency;
}
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 61b64c2b2cb8..48eaf2879228 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -324,8 +324,9 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
expected_interval = get_typical_interval(data);
expected_interval = min(expected_interval, data->next_timer_us);
- if (CPUIDLE_DRIVER_STATE_START > 0) {
- struct cpuidle_state *s = &drv->states[CPUIDLE_DRIVER_STATE_START];
+ first_idx = 0;
+ if (drv->states[0].flags & CPUIDLE_FLAG_POLLING) {
+ struct cpuidle_state *s = &drv->states[1];
unsigned int polling_threshold;
/*
@@ -336,12 +337,8 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
polling_threshold = max_t(unsigned int, 20, s->target_residency);
if (data->next_timer_us > polling_threshold &&
latency_req > s->exit_latency && !s->disabled &&
- !dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable)
- first_idx = CPUIDLE_DRIVER_STATE_START;
- else
- first_idx = CPUIDLE_DRIVER_STATE_START - 1;
- } else {
- first_idx = 0;
+ !dev->states_usage[1].disable)
+ first_idx = 1;
}
/*