3.12.38-rt53-rc2 stable review patch.
If anyone has any objections, please let me know.
------------------
From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
This reverts commit e8886d18e87ca7a578cd85467418a0de693588ca
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Conflicts:
kernel/timer.c
---
include/linux/hrtimer.h | 3 ++-
kernel/hrtimer.c | 31 ++++++++++++++++++++++++-------
kernel/timer.c | 46 ++--------------------------------------------
3 files changed, 28 insertions(+), 52 deletions(-)
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index bdbf77db0f4d..79a7a35e1a6e 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -461,8 +461,9 @@ extern int schedule_hrtimeout_range_clock(ktime_t *expires,
unsigned long delta, const enum hrtimer_mode mode, int clock);
extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
-/* Called from the periodic timer tick */
+/* Soft interrupt function to run the hrtimer queues: */
extern void hrtimer_run_queues(void);
+extern void hrtimer_run_pending(void);
/* Bootup initialization: */
extern void __init hrtimers_init(void);
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index c967b718ab37..ba64ab0d5792 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1716,6 +1716,30 @@ static void run_hrtimer_softirq(struct softirq_action *h)
}
/*
+ * Called from timer softirq every jiffy, expire hrtimers:
+ *
+ * For HRT its the fall back code to run the softirq in the timer
+ * softirq context in case the hrtimer initialization failed or has
+ * not been done yet.
+ */
+void hrtimer_run_pending(void)
+{
+ if (hrtimer_hres_active())
+ return;
+
+ /*
+ * This _is_ ugly: We have to check in the softirq context,
+ * whether we can switch to highres and / or nohz mode. The
+ * clocksource switch happens in the timer interrupt with
+ * xtime_lock held. Notification from there only sets the
+ * check bit in the tick_oneshot code, otherwise we might
+ * deadlock vs. xtime_lock.
+ */
+ if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
+ hrtimer_switch_to_hres();
+}
+
+/*
* Called from hardirq context every jiffy
*/
void hrtimer_run_queues(void)
@@ -1728,13 +1752,6 @@ void hrtimer_run_queues(void)
if (hrtimer_hres_active())
return;
- /*
- * Check whether we can switch to highres mode.
- */
- if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())
- && hrtimer_switch_to_hres())
- return;
-
for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
base = &cpu_base->clock_base[index];
if (!timerqueue_getnext(&base->active))
diff --git a/kernel/timer.c b/kernel/timer.c
index 0ee72212b99c..2d9ba1b9f698 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1464,6 +1464,8 @@ static void run_timer_softirq(struct softirq_action *h)
{
struct tvec_base *base = __this_cpu_read(tvec_bases);
+ hrtimer_run_pending();
+
#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
irq_work_run();
#endif
@@ -1477,52 +1479,8 @@ static void run_timer_softirq(struct softirq_action *h)
*/
void run_local_timers(void)
{
- struct tvec_base *base = __this_cpu_read(tvec_bases);
-
hrtimer_run_queues();
- /*
- * We can access this lockless as we are in the timer
- * interrupt. If there are no timers queued, nothing to do in
- * the timer softirq.
- */
-#ifdef CONFIG_PREEMPT_RT_FULL
-
-#ifndef CONFIG_SMP
- /*
- * The spin_do_trylock() later may fail as the lock may be hold before
- * the interrupt arrived. The spin-lock debugging code will raise a
- * warning if the try_lock fails on UP. Since this is only an
- * optimization for the FULL_NO_HZ case (not to run the timer softirq on
- * an nohz_full CPU) we don't really care and shedule the softirq.
- */
raise_softirq(TIMER_SOFTIRQ);
- return;
-#endif
-
- /* On RT, irq work runs from softirq */
- if (irq_work_needs_cpu()) {
- raise_softirq(TIMER_SOFTIRQ);
- return;
- }
-
- if (!spin_do_trylock(&base->lock)) {
- raise_softirq(TIMER_SOFTIRQ);
- return;
- }
-#endif
-
- if (!base->active_timers)
- goto out;
-
- /* Check whether the next pending timer has expired */
- if (time_before_eq(base->next_timer, jiffies))
- raise_softirq(TIMER_SOFTIRQ);
-out:
-#ifdef CONFIG_PREEMPT_RT_FULL
- rt_spin_unlock_after_trylock_in_irq(&base->lock);
-#endif
- /* The ; ensures that gcc won't complain in the !RT case */
- ;
}
#ifdef __ARCH_WANT_SYS_ALARM
--
2.1.4
--
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