Re: [PATCH 3/4] Make net watchdog timers 1 sec jiffy aligned

On Wed, 30 May 2007 10:59:36 -0700
Andrew Morton [off-list ref] wrote:

On Tue, 29 May 2007 11:01:13 -0700
Venki Pallipadi [off-list ref] wrote:

quoted

round_jiffies for net dev watchdog timer.

Signed-off-by: Venkatesh Pallipadi <redacted>

Index: linux-2.6.22-rc-mm/net/sched/sch_generic.c
===================================================================

--- linux-2.6.22-rc-mm.orig/net/sched/sch_generic.c	2007-05-24 11:16:03.000000000 -0700
+++ linux-2.6.22-rc-mm/net/sched/sch_generic.c	2007-05-25 15:10:02.000000000 -0700

@@ -224,7 +224,8 @@
 	if (dev->tx_timeout) {
 		if (dev->watchdog_timeo <= 0)
 			dev->watchdog_timeo = 5*HZ;
-		if (!mod_timer(&dev->watchdog_timer, jiffies + dev->watchdog_timeo))
+		if (!mod_timer(&dev->watchdog_timer,
+			       round_jiffies(jiffies + dev->watchdog_timeo)))
 			dev_hold(dev);
 	}
 }

Please cc netdev on net patches.

Again, I worry that if people set the watchdog timeout to, say, 0.1 seconds
then they will get one second, which is grossly different.

And if they were to set it to 1.5 seconds, they'd get 2.0 which is pretty
significant, too.

Alternatively, we could change to a timer that is pushed forward after each
TX, maybe using hrtimer and hrtimer_forward().  That way the timer would
never run in normal case.

-- 
Stephen Hemminger [off-list ref]