[patch -mm 11/28] hrtimer: speedup hrtimer_enqueue

Thomas Gleixner
2007-06-23T13:25:46Z

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From: Ingo Molnar <mingo@elte.hu>

Speedup hrtimer_enqueue by evaluating the rbtree insertion result.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
kernel/hrtimer.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

Index: linux-2.6.22-rc4-mm/kernel/hrtimer.c
===================================================================
--- linux-2.6.22-rc4-mm.orig/kernel/hrtimer.c 2007-06-23 14:38:58.000000000 +0200
+++ linux-2.6.22-rc4-mm/kernel/hrtimer.c 2007-06-23 14:38:58.000000000 +0200
@@ -686,6 +686,7 @@ static void enqueue_hrtimer(struct hrtim
struct rb_node **link = &base->active.rb_node;
struct rb_node *parent = NULL;
struct hrtimer *entry;
+ int leftmost = 1;

/*
* Find the right place in the rbtree:
@@ -697,18 +698,19 @@ static void enqueue_hrtimer(struct hrtim
* We dont care about collisions. Nodes with
* the same expiry time stay together.
*/
- if (timer->expires.tv64 < entry->expires.tv64)
+ if (timer->expires.tv64 < entry->expires.tv64) {
link = &(*link)->rb_left;
- else
+ } else {
link = &(*link)->rb_right;
+ leftmost = 0;
+ }
}

/*
* Insert the timer to the rbtree and check whether it
* replaces the first pending timer
*/
- if (!base->first || timer->expires.tv64 <
- rb_entry(base->first, struct hrtimer, node)->expires.tv64) {
+ if (leftmost) {
/*
* Reprogram the clock event device. When the timer is already
* expired hrtimer_enqueue_reprogram has either called the

--