hrtimer: migrate pending list on cpu offline

Impact: hrtimers which are on the pending list are not migrated at cpu
	offline and can be stale forever

Add the pending list migration when CONFIG_HIGH_RES_TIMERS is enabled

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 33 insertions, 1 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index b8e4dce80a74..580bc66ae136 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1610,10 +1610,36 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
         }
 }
 
+#ifdef CONFIG_HIGH_RES_TIMERS
+static int migrate_hrtimer_pending(struct hrtimer_cpu_base *old_base,
+                                   struct hrtimer_cpu_base *new_base)
+{
+        struct hrtimer *timer;
+        int raise = 0;
+
+        while (!list_empty(&old_base->cb_pending)) {
+                timer = list_entry(old_base->cb_pending.next,
+                                   struct hrtimer, cb_entry);
+
+                __remove_hrtimer(timer, timer->base, HRTIMER_STATE_PENDING, 0);
+                timer->base = &new_base->clock_base[timer->base->index];
+                list_add_tail(&timer->cb_entry, &new_base->cb_pending);
+                raise = 1;
+        }
+        return raise;
+}
+#else
+static int migrate_hrtimer_pending(struct hrtimer_cpu_base *old_base,
+                                   struct hrtimer_cpu_base *new_base)
+{
+        return 0;
+}
+#endif
+
 static void migrate_hrtimers(int cpu)
 {
         struct hrtimer_cpu_base *old_base, *new_base;
-        int i;
+        int i, raise = 0;
 
         BUG_ON(cpu_online(cpu));
         old_base = &per_cpu(hrtimer_bases, cpu);
@@ -1630,10 +1656,16 @@ static void migrate_hrtimers(int cpu)
                                      &new_base->clock_base[i]);
         }
 
+        if (migrate_hrtimer_pending(old_base, new_base))
+                raise = 1;
+
         spin_unlock(&old_base->lock);
         spin_unlock(&new_base->lock);
         local_irq_enable();
         put_cpu_var(hrtimer_bases);
+
+        if (raise)
+                hrtimer_raise_softirq();
 }
 #endif /* CONFIG_HOTPLUG_CPU */