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Date: Tue, 19 Mar 2013 12:50:34 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
RT <linux-rt-users@...r.kernel.org>
Subject: Fixup for 3.4.34 merge conflict
Thomas,
Merging 3.4.34 into stable 3.4-rt I hit the following conflict:
diff --cc kernel/hrtimer.c
index 9114899,cdd5607..0000000
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@@ -643,30 -640,9 +643,33 @@@ static inline void hrtimer_init_hres(st
* and expiry check is done in the hrtimer_interrupt or in the softirq.
*/
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
- struct hrtimer_clock_base *base,
- int wakeup)
+ struct hrtimer_clock_base *base)
{
++<<<<<<< HEAD
+ if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
+ if (!wakeup)
+ return -ETIME;
+
+#ifdef CONFIG_PREEMPT_RT_BASE
+ /*
+ * Move softirq based timers away from the rbtree in
+ * case it expired already. Otherwise we would have a
+ * stale base->first entry until the softirq runs.
+ */
+ if (!hrtimer_rt_defer(timer))
+ return -ETIME;
+#endif
+ raw_spin_unlock(&base->cpu_base->lock);
+ raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ raw_spin_lock(&base->cpu_base->lock);
+
+ return 0;
+ }
+
+ return 0;
++=======
+ return base->cpu_base->hres_active && hrtimer_reprogram(timer, base);
++>>>>>>> v3.4.34
}
static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
@@@ -1054,18 -982,19 +1056,34 @@@ int __hrtimer_start_range_ns(struct hrt
*
* XXX send_remote_softirq() ?
*/
++<<<<<<< HEAD
+ if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)) {
+ ret = hrtimer_enqueue_reprogram(timer, new_base, wakeup);
+ if (ret) {
+ /*
+ * In case we failed to reprogram the timer (mostly
+ * because out current timer is already elapsed),
+ * remove it again and report a failure. This avoids
+ * stale base->first entries.
+ */
+ debug_deactivate(timer);
+ __remove_hrtimer(timer, new_base,
+ timer->state & HRTIMER_STATE_CALLBACK, 0);
++=======
+ if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)
+ && hrtimer_enqueue_reprogram(timer, new_base)) {
+ if (wakeup) {
+ /*
+ * We need to drop cpu_base->lock to avoid a
+ * lock ordering issue vs. rq->lock.
+ */
+ raw_spin_unlock(&new_base->cpu_base->lock);
+ raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ local_irq_restore(flags);
+ return ret;
+ } else {
+ __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
++>>>>>>> v3.4.34
}
}
As 3.4.34 stable included commit b22affe0a "hrtimer: Prevent
hrtimer_enqueue_reprogram race" which conflicts with the current code in
-rt as you can see above.
Below is the final change I did to handle this code. I'm running tests
on it now. I tried to keep the same basic logic that -rt has. Let me
know if you have issues with this. I'll wait a few days before I push
this to kernel.org.
-- Steve
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 9114899..2328c04 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -643,30 +643,9 @@ static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
* and expiry check is done in the hrtimer_interrupt or in the softirq.
*/
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
- struct hrtimer_clock_base *base,
- int wakeup)
+ struct hrtimer_clock_base *base)
{
- if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
- if (!wakeup)
- return -ETIME;
-
-#ifdef CONFIG_PREEMPT_RT_BASE
- /*
- * Move softirq based timers away from the rbtree in
- * case it expired already. Otherwise we would have a
- * stale base->first entry until the softirq runs.
- */
- if (!hrtimer_rt_defer(timer))
- return -ETIME;
-#endif
- raw_spin_unlock(&base->cpu_base->lock);
- raise_softirq_irqoff(HRTIMER_SOFTIRQ);
- raw_spin_lock(&base->cpu_base->lock);
-
- return 0;
- }
-
- return 0;
+ return base->cpu_base->hres_active && hrtimer_reprogram(timer, base);
}
static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
@@ -747,8 +726,7 @@ static inline int hrtimer_switch_to_hres(void) { return 0; }
static inline void
hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
- struct hrtimer_clock_base *base,
- int wakeup)
+ struct hrtimer_clock_base *base)
{
return 0;
}
@@ -1054,19 +1032,39 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
*
* XXX send_remote_softirq() ?
*/
- if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)) {
- ret = hrtimer_enqueue_reprogram(timer, new_base, wakeup);
- if (ret) {
+ if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)
+ && hrtimer_enqueue_reprogram(timer, new_base)) {
+
+ if (wakeup
+#ifdef CONFIG_PREEMPT_RT_BASE
+ /*
+ * Move softirq based timers away from the rbtree in
+ * case it expired already. Otherwise we would have a
+ * stale base->first entry until the softirq runs.
+ */
+ && hrtimer_rt_defer(timer)
+#endif
+ ) {
/*
- * In case we failed to reprogram the timer (mostly
- * because out current timer is already elapsed),
- * remove it again and report a failure. This avoids
- * stale base->first entries.
+ * We need to drop cpu_base->lock to avoid a
+ * lock ordering issue vs. rq->lock.
*/
- debug_deactivate(timer);
- __remove_hrtimer(timer, new_base,
- timer->state & HRTIMER_STATE_CALLBACK, 0);
+ raw_spin_unlock(&new_base->cpu_base->lock);
+ raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ local_irq_restore(flags);
+ return ret;
}
+
+ /*
+ * In case we failed to reprogram the timer (mostly
+ * because out current timer is already elapsed),
+ * remove it again and report a failure. This avoids
+ * stale base->first entries.
+ */
+ debug_deactivate(timer);
+ __remove_hrtimer(timer, new_base,
+ timer->state & HRTIMER_STATE_CALLBACK, 0);
+ ret = -ETIME;
}
unlock_hrtimer_base(timer, &flags);
--
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