Xen devel - Mar 2007 - [PATCH] linux: fix condition for entering tickless state

I noticed that timer interrupts were running at full rate regardless
of whether the system was idle.
softlockup_get_next_event() must return the maximum of zero and the
delta to the next event, not the minimum (which is always zero or
negative, yielding zero or a very large positive number as return
value).

Signed-off-by: Jan Beulich <jbeulich@novell.com>

Index: ./patches/linux-2.6.18/softlockup-no-idle-hz.patch
==================================================================---
./patches/linux-2.6.18/softlockup-no-idle-hz.patch
+++ ./patches/linux-2.6.18/softlockup-no-idle-hz.patch
@@ -34,7 +34,7 @@ unsigned long softlockup_get_next_event(
 +			!per_cpu(watchdog_task, this_cpu))
 +		return MAX_JIFFY_OFFSET;
 +
-+	return min_t(long, 0, touch_timestamp + HZ - jiffies);
++	return max_t(long, 0, touch_timestamp + HZ - jiffies);
 +}
 +
  /*



_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

On 9/3/07 16:54, "Jan Beulich" <jbeulich@novell.com> wrote:
> I noticed that timer interrupts were running at full rate regardless
> of whether the system was idle.
> softlockup_get_next_event() must return the maximum of zero and the
> delta to the next event, not the minimum (which is always zero or
> negative, yielding zero or a very large positive number as return
> value).
Oops. :-)

 K.


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel