simple mod_timer patch

[Steve Modica <modica@sgi.com>]

I pulled this back from the 2.6 kernel to reduce some serious contention on the 
timerlist_lock when I had 8 gigabit cards runnings.


diff -u -r1.23 -r1.24
--- linux/linux/kernel/timer.c       2003/08/11 20:16:19     1.23
+++ linux/linux/kernel/timer.c       2003/10/01 21:09:20     1.24
@@ -207,6 +207,14 @@
         int ret;
         unsigned long flags;

+        /*
+        * This is a common optimization triggered by the
+        * networking code - if the timer is re-modified
+        * to be the same thing then just return:
+        */
+        if (timer->expires == expires && timer_pending(timer))
+               return 1;
+
         spin_lock_irqsave(&timerlist_lock, flags);
         timer->expires = expires;
         ret = detach_timer(timer);



-- 
Steve Modica
work: 651-683-3224
MTS-Technical Lead
"Give a man a fish, and he will eat for a day, hit him with a fish and
he leaves you alone" - me