From: Ingo Molnar <mingo@elte.hu>
Date: Sat, 21 Jul 2007 11:37:36 +0000 (-0700)
Subject: hrtimer: speedup hrtimer_enqueue
X-Git-Tag: v2.6.23-rc1~174
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=99bc2fcb283852931fb6bbef40f3df8316b59000;p=karo-tx-linux.git

hrtimer: speedup hrtimer_enqueue

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>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 065a89786628..eb1ddebd2c04 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -686,6 +686,7 @@ static void enqueue_hrtimer(struct hrtimer *timer,
 	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 hrtimer *timer,
 		 * 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