clock_was_set() cannot be called from hard interrupt context because
it calls on_each_cpu(). For fixing the widely reported leap seconds
issue it's necessary to call it from the timer interrupt context.
Provide a new function which denotes it in the hrtimer cpu base
structure of the cpu on which it is called and raising the timer
softirq.
We then execute the clock_was_set() notificiation in the timer softirq
context in hrtimer_run_pending().
CC: Ingo Molnar <mi...@kernel.org>
CC: Peter Zijlstra <a.p.zijls...@chello.nl>
CC: Prarit Bhargava <pra...@redhat.com>
CC: Thomas Gleixner <t...@linutronix.de>
CC: sta...@vger.kernel.org
Reported-by: Jan Engelhardt <jeng...@inai.de>
Signed-off-by: John Stultz <johns...@us.ibm.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: John Stultz <johns...@us.ibm.com>
---
include/linux/hrtimer.h | 5 ++++-
kernel/hrtimer.c | 20 ++++++++++++++++++++
2 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index fd0dc30..4c3dac8 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -165,6 +165,7 @@ enum hrtimer_base_type {
* @lock: lock protecting the base and associated clock bases
* and timers
* @active_bases: Bitfield to mark bases with active timers
+ * @clock_was_set: Indicates that clock was set from irq context.
* @expires_next: absolute time of the next event which was scheduled
* via clock_set_next_event()
* @hres_active: State of high resolution mode
@@ -177,7 +178,8 @@ enum hrtimer_base_type {
*/
struct hrtimer_cpu_base {
raw_spinlock_t lock;
- unsigned long active_bases;
+ unsigned int active_bases;
+ unsigned int clock_was_set;
#ifdef CONFIG_HIGH_RES_TIMERS
ktime_t expires_next;
int hres_active;
@@ -309,6 +311,7 @@ static inline int hrtimer_is_hres_active(struct hrtimer
*timer)
#endif
extern void clock_was_set(void);
+extern void clock_was_set_delayed(void);
#ifdef CONFIG_TIMERFD
extern void timerfd_clock_was_set(void);
#else
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index ae34bf5..7c20cb8 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -756,6 +756,19 @@ void clock_was_set(void)
}
/*
+ * Called from timekeeping code to reprogramm the hrtimer interrupt
+ * device. If called from the timer interrupt context we defer it to
+ * softirq context.
+ */
+void clock_was_set_delayed(void)
+{
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+
+ cpu_base->clock_was_set = 1;
+ __raise_softirq_irqoff(TIMER_SOFTIRQ);
+}
+
+/*
* During resume we might have to reprogram the high resolution timer
* interrupt (on the local CPU):
*/
@@ -1413,6 +1426,13 @@ static inline void __hrtimer_peek_ahead_timers(void) { }
*/
void hrtimer_run_pending(void)
{
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+
+ if (cpu_base->clock_was_set) {
+ cpu_base->clock_was_set = 0;
+ clock_was_set();
+ }
+
if (hrtimer_hres_active())
return;
--
1.7.9.5
--
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