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authorThomas Gleixner <tglx@linutronix.de>2021-07-13 16:39:51 +0300
committerThomas Gleixner <tglx@linutronix.de>2021-08-10 18:57:23 +0300
commita761a67f591a8c7476c30bb20ed0f09fdfb1a704 (patch)
treeb3a19dfca4e52fde11ceb2ba23447130cc3408ee
parent66f7b0c8aadd2785fc29f2c71477ebc16f4e38cc (diff)
downloadlinux-a761a67f591a8c7476c30bb20ed0f09fdfb1a704.tar.xz
timekeeping: Distangle resume and clock-was-set events
Resuming timekeeping is a clock-was-set event and uses the clock-was-set notification mechanism. This is in the way of making the clock-was-set update for hrtimers selective so unnecessary IPIs are avoided when a CPU base does not have timers queued which are affected by the clock setting. Distangle it by invoking hrtimer_resume() on each unfreezing CPU and invoke the new timerfd_resume() function from timekeeping_resume() which is the only place where this is needed. Rename hrtimer_resume() to hrtimer_resume_local() to reflect the change. With this the clock_was_set*() functions are not longer required to IPI all CPUs unconditionally and can get some smarts to avoid them. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210713135158.488853478@linutronix.de
-rw-r--r--include/linux/hrtimer.h1
-rw-r--r--kernel/time/hrtimer.c15
-rw-r--r--kernel/time/tick-common.c7
-rw-r--r--kernel/time/tick-internal.h2
-rw-r--r--kernel/time/timekeeping.c4
5 files changed, 18 insertions, 11 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 253c6e25f331..0ee140176f10 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -354,7 +354,6 @@ extern void timerfd_resume(void);
static inline void timerfd_clock_was_set(void) { }
static inline void timerfd_resume(void) { }
#endif
-extern void hrtimers_resume(void);
DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 214fd65a9597..68e56f0ecb09 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -900,8 +900,8 @@ static void clock_was_set_work(struct work_struct *work)
static DECLARE_WORK(hrtimer_work, clock_was_set_work);
/*
- * Called from timekeeping and resume code to reprogram the hrtimer
- * interrupt device on all cpus and to notify timerfd.
+ * Called from timekeeping code to reprogram the hrtimer interrupt device
+ * on all cpus and to notify timerfd.
*/
void clock_was_set_delayed(void)
{
@@ -909,18 +909,15 @@ void clock_was_set_delayed(void)
}
/*
- * During resume we might have to reprogram the high resolution timer
- * interrupt on all online CPUs. However, all other CPUs will be
- * stopped with IRQs interrupts disabled so the clock_was_set() call
- * must be deferred.
+ * Called during resume either directly from via timekeeping_resume()
+ * or in the case of s2idle from tick_unfreeze() to ensure that the
+ * hrtimers are up to date.
*/
-void hrtimers_resume(void)
+void hrtimers_resume_local(void)
{
lockdep_assert_irqs_disabled();
/* Retrigger on the local CPU */
retrigger_next_event(NULL);
- /* And schedule a retrigger for all others */
- clock_was_set_delayed();
}
/*
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index d663249652ef..46789356f856 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -470,6 +470,13 @@ void tick_resume_local(void)
else
tick_resume_oneshot();
}
+
+ /*
+ * Ensure that hrtimers are up to date and the clockevents device
+ * is reprogrammed correctly when high resolution timers are
+ * enabled.
+ */
+ hrtimers_resume_local();
}
/**
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index cd610faa2523..22de98cc6dd8 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -168,3 +168,5 @@ void timer_clear_idle(void);
void clock_was_set(void);
void clock_was_set_delayed(void);
+
+void hrtimers_resume_local(void);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 8a364aa9881a..c8a9b9e54c9d 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1810,8 +1810,10 @@ void timekeeping_resume(void)
touch_softlockup_watchdog();
+ /* Resume the clockevent device(s) and hrtimers */
tick_resume();
- hrtimers_resume();
+ /* Notify timerfd as resume is equivalent to clock_was_set() */
+ timerfd_resume();
}
int timekeeping_suspend(void)