Re: [patch 43/69] i386: HPET, check if the counter works

From: Thomas Gleixner
Date: Mon May 21 2007 - 16:01:41 EST


On Mon, 2007-05-21 at 12:16 -0700, Chris Wright wrote:
> plain text document attachment
> (i386-hpet-check-if-the-counter-works.patch)
> -stable review patch. If anyone has any objections, please let us know.
> ---------------------
>
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>
> Some systems have a HPET which is not incrementing, which leads to a
> complete hang. Detect it during HPET setup.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
> ---
> [chrisw: Why is this not upstream yet?]

Dunno. There is another one missing:

------------------------------->
Subject: NOHZ: Rate limit the local softirq pending warning output

The warning in the NOHZ code, which triggers when a CPU goes idle with
softirqs pending can fill up the logs quite quickly. Rate limit the
output until we found the root cause of that problem.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Index: linux-2.6.21/kernel/time/tick-sched.c
===================================================================
--- linux-2.6.21.orig/kernel/time/tick-sched.c
+++ linux-2.6.21/kernel/time/tick-sched.c
@@ -167,9 +167,15 @@ void tick_nohz_stop_sched_tick(void)
goto end;

cpu = smp_processor_id();
- if (unlikely(local_softirq_pending()))
- printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
- local_softirq_pending());
+ if (unlikely(local_softirq_pending())) {
+ static int ratelimit;
+
+ if (ratelimit < 10) {
+ printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
+ local_softirq_pending());
+ ratelimit++;
+ }
+ }

now = ktime_get();
/*


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