Re: [RFC][PATCH] TIMER_BH-less smptimers

[Anton Blanchard <anton@samba.org>]

Hi Dipankar,

> I have been experimenting with Ingo's smptimers and I ended up
> extending it a little bit. I would really appreciate comments
> on whether these things make sense or not.

I tried it out and found that we were context switching like crazy.
It seems we were always running the timers out of a tasklet because
we never unlocked the net_bh_lock.

Anton

diff -urN linux-2.5_smptimers/kernel/timer.c linux-2.5_tux/kernel/timer.c
--- linux-2.5_smptimers/kernel/timer.c	Mon May 20 18:48:18 2002
+++ linux-2.5_tux/kernel/timer.c	Mon May 20 18:41:32 2002
@@ -694,6 +694,7 @@
 		__run_timers(base);
 
         hardirq_endlock(cpu);
+        spin_unlock(&net_bh_lock);
         spin_unlock(&global_bh_lock);
         return;
 resched_net:
@@ -733,6 +734,7 @@
 		__run_timers(base);
 
 	hardirq_endlock(cpu);
+	spin_unlock(&net_bh_lock);
 	spin_unlock(&global_bh_lock);
 	local_irq_enable();
 	local_bh_enable();