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authorPeter Zijlstra <peterz@infradead.org>2020-09-15 13:32:00 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-09-16 20:36:26 +0300
commit8747f2022fe8d8029193707ee86ff5c792cbef9b (patch)
treefdb28a11eb16c420a68394a907eb7c5f9e5c10d4 /drivers/cpuidle
parenta889a23a98fee183c9b6b0b14b2fd70583429c5e (diff)
downloadlinux-8747f2022fe8d8029193707ee86ff5c792cbef9b.tar.xz
cpuidle: Allow cpuidle drivers to take over RCU-idle
Some drivers have to do significant work, some of which relies on RCU still being active. Instead of using RCU_NONIDLE in the drivers and flipping RCU back on, allow drivers to take over RCU-idle duty. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Tested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/cpuidle.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 04becd70cc41..6c7e5621cf9a 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -138,6 +138,7 @@ static void enter_s2idle_proper(struct cpuidle_driver *drv,
struct cpuidle_device *dev, int index)
{
ktime_t time_start, time_end;
+ struct cpuidle_state *target_state = &drv->states[index];
time_start = ns_to_ktime(local_clock());
@@ -153,8 +154,9 @@ static void enter_s2idle_proper(struct cpuidle_driver *drv,
* suspended is generally unsafe.
*/
stop_critical_timings();
- rcu_idle_enter();
- drv->states[index].enter_s2idle(dev, drv, index);
+ if (!(target_state->flags & CPUIDLE_FLAG_RCU_IDLE))
+ rcu_idle_enter();
+ target_state->enter_s2idle(dev, drv, index);
if (WARN_ON_ONCE(!irqs_disabled()))
local_irq_disable();
/*
@@ -162,7 +164,8 @@ static void enter_s2idle_proper(struct cpuidle_driver *drv,
* first CPU executing it calls functions containing RCU read-side
* critical sections, so tell RCU about that.
*/
- rcu_idle_exit();
+ if (!(target_state->flags & CPUIDLE_FLAG_RCU_IDLE))
+ rcu_idle_exit();
tick_unfreeze();
start_critical_timings();
@@ -239,9 +242,11 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
time_start = ns_to_ktime(local_clock());
stop_critical_timings();
- rcu_idle_enter();
+ if (!(target_state->flags & CPUIDLE_FLAG_RCU_IDLE))
+ rcu_idle_enter();
entered_state = target_state->enter(dev, drv, index);
- rcu_idle_exit();
+ if (!(target_state->flags & CPUIDLE_FLAG_RCU_IDLE))
+ rcu_idle_exit();
start_critical_timings();
sched_clock_idle_wakeup_event();