summaryrefslogtreecommitdiff
path: root/drivers/cpuidle
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 17:42:36 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 17:42:36 +0300
commitdfec4a8478e8e81483a94b663f13153bb7796800 (patch)
treef78f0cac1f93b6a3b2a8f3a2a78fb84c04be97d3 /drivers/cpuidle
parent159127ea8318974b76542f62d6d23ec8bec91a28 (diff)
parent01ac7c4c2e035bc8d0d47dc880bbc25bf562a648 (diff)
downloadlinux-dfec4a8478e8e81483a94b663f13153bb7796800.tar.xz
Merge tag 'pm-4.19-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more power management updates from Rafael Wysocki: "These fix the main idle loop and the menu cpuidle governor, clean up the latter, fix a mistake in the PCI bus type's support for system suspend and resume, fix the ondemand and conservative cpufreq governors, address a build issue in the system wakeup framework and make the ACPI C-states desciptions less confusing. Specifics: - Make the idle loop handle stopped scheduler tick correctly (Rafael Wysocki). - Prevent the menu cpuidle governor from letting CPUs spend too much time in shallow idle states when it is invoked with scheduler tick stopped and clean it up somewhat (Rafael Wysocki). - Avoid invoking the platform firmware to make the platform enter the ACPI S3 sleep state with suspended PCIe root ports which may confuse the firmware and cause it to crash (Rafael Wysocki). - Fix sysfs-related race in the ondemand and conservative cpufreq governors which may cause the system to crash if the governor module is removed during an update of CPU frequency limits (Henry Willard). - Select SRCU when building the system wakeup framework to avoid a build issue in it (zhangyi). - Make the descriptions of ACPI C-states vendor-neutral to avoid confusion (Prarit Bhargava)" * tag 'pm-4.19-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: cpuidle: menu: Handle stopped tick more aggressively sched: idle: Avoid retaining the tick when it has been stopped PCI / ACPI / PM: Resume all bridges on suspend-to-RAM cpuidle: menu: Update stale polling override comment cpufreq: governor: Avoid accessing invalid governor_data x86/ACPI/cstate: Make APCI C1 FFH MWAIT C-state description vendor-neutral cpuidle: menu: Fix white space PM / sleep: wakeup: Fix build error caused by missing SRCU support
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/governors/menu.c45
1 files changed, 28 insertions, 17 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 1aef60d160eb..110483f0e3fb 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -328,9 +328,8 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
unsigned int polling_threshold;
/*
- * We want to default to C1 (hlt), not to busy polling
- * unless the timer is happening really really soon, or
- * C1's exit latency exceeds the user configured limit.
+ * Default to a physical idle state, not to busy polling, unless
+ * a timer is going to trigger really really soon.
*/
polling_threshold = max_t(unsigned int, 20, s->target_residency);
if (data->next_timer_us > polling_threshold &&
@@ -349,14 +348,12 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
* If the tick is already stopped, the cost of possible short
* idle duration misprediction is much higher, because the CPU
* may be stuck in a shallow idle state for a long time as a
- * result of it. In that case say we might mispredict and try
- * to force the CPU into a state for which we would have stopped
- * the tick, unless a timer is going to expire really soon
- * anyway.
+ * result of it. In that case say we might mispredict and use
+ * the known time till the closest timer event for the idle
+ * state selection.
*/
if (data->predicted_us < TICK_USEC)
- data->predicted_us = min_t(unsigned int, TICK_USEC,
- ktime_to_us(delta_next));
+ data->predicted_us = ktime_to_us(delta_next);
} else {
/*
* Use the performance multiplier and the user-configurable
@@ -381,8 +378,22 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
continue;
if (idx == -1)
idx = i; /* first enabled state */
- if (s->target_residency > data->predicted_us)
- break;
+ if (s->target_residency > data->predicted_us) {
+ if (!tick_nohz_tick_stopped())
+ break;
+
+ /*
+ * If the state selected so far is shallow and this
+ * state's target residency matches the time till the
+ * closest timer event, select this one to avoid getting
+ * stuck in the shallow one for too long.
+ */
+ if (drv->states[idx].target_residency < TICK_USEC &&
+ s->target_residency <= ktime_to_us(delta_next))
+ idx = i;
+
+ goto out;
+ }
if (s->exit_latency > latency_req) {
/*
* If we break out of the loop for latency reasons, use
@@ -403,14 +414,13 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
* Don't stop the tick if the selected state is a polling one or if the
* expected idle duration is shorter than the tick period length.
*/
- if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) ||
- expected_interval < TICK_USEC) {
+ if (((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) ||
+ expected_interval < TICK_USEC) && !tick_nohz_tick_stopped()) {
unsigned int delta_next_us = ktime_to_us(delta_next);
*stop_tick = false;
- if (!tick_nohz_tick_stopped() && idx > 0 &&
- drv->states[idx].target_residency > delta_next_us) {
+ if (idx > 0 && drv->states[idx].target_residency > delta_next_us) {
/*
* The tick is not going to be stopped and the target
* residency of the state to be returned is not within
@@ -418,8 +428,8 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
* tick, so try to correct that.
*/
for (i = idx - 1; i >= 0; i--) {
- if (drv->states[i].disabled ||
- dev->states_usage[i].disable)
+ if (drv->states[i].disabled ||
+ dev->states_usage[i].disable)
continue;
idx = i;
@@ -429,6 +439,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
}
}
+out:
data->last_state_idx = idx;
return data->last_state_idx;