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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-01-25 21:08:31 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-25 21:08:31 +0100
commit2d44ae4d7135b9aee26439b3523b43473381bc5f (patch)
treeba3afc0f03142d26f9238974dab5b99bf1dca1db /kernel/hrtimer.c
parent48d5e258216f1c7713633439beb98a38c7290649 (diff)
downloadblackbird-op-linux-2d44ae4d7135b9aee26439b3523b43473381bc5f.tar.gz
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hrtimer: clean up cpu->base locking tricks
In order to more easily allow for the scheduler to use timers, clean up the locking a bit. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/hrtimer.c')
-rw-r--r--kernel/hrtimer.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index f994bb8065e6..9f850ca032b6 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1063,7 +1063,9 @@ void hrtimer_interrupt(struct clock_event_device *dev)
basenow = ktime_add(now, base->offset);
while ((node = base->first)) {
+ enum hrtimer_restart (*fn)(struct hrtimer *);
struct hrtimer *timer;
+ int restart;
timer = rb_entry(node, struct hrtimer, node);
@@ -1091,13 +1093,29 @@ void hrtimer_interrupt(struct clock_event_device *dev)
HRTIMER_STATE_CALLBACK, 0);
timer_stats_account_hrtimer(timer);
+ fn = timer->function;
+ if (timer->cb_mode == HRTIMER_CB_IRQSAFE_NO_SOFTIRQ) {
+ /*
+ * Used for scheduler timers, avoid lock
+ * inversion with rq->lock and tasklist_lock.
+ *
+ * These timers are required to deal with
+ * enqueue expiry themselves and are not
+ * allowed to migrate.
+ */
+ spin_unlock(&cpu_base->lock);
+ restart = fn(timer);
+ spin_lock(&cpu_base->lock);
+ } else
+ restart = fn(timer);
+
/*
* Note: We clear the CALLBACK bit after
* enqueue_hrtimer to avoid reprogramming of
* the event hardware. This happens at the end
* of this function anyway.
*/
- if (timer->function(timer) != HRTIMER_NORESTART) {
+ if (restart != HRTIMER_NORESTART) {
BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
enqueue_hrtimer(timer, base, 0);
}
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