Re: [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750jiffies)

From: Folkert van Heusden
Date: Fri Nov 21 2008 - 10:34:54 EST


> > I'm afraid there's no script for that: it happens during boot.
>
> This is a HZ=250 machine, correct? If so, please try the following
> patch (already in -tip), which helps suppress boot-time false positives.

That's correct, 250Hz.

> diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h
> index 5f89b62..301dda8 100644
> --- a/include/linux/rcuclassic.h
> +++ b/include/linux/rcuclassic.h
> @@ -41,7 +41,7 @@
> #include <linux/seqlock.h>
>
> #ifdef CONFIG_RCU_CPU_STALL_DETECTOR
> -#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */
> +#define RCU_SECONDS_TILL_STALL_CHECK (10 * HZ) /* for rcp->jiffies_stall */

Isn't it better to let the define depend on the value of CONFIG_HZ?
E.g.

Signed-off-by: Folkert van Heusden <folkert@xxxxxxxxxxxxxx>

diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h
index 5f89b62..301dda8 100644
--- a/include/linux/rcuclassic.h
+++ b/include/linux/rcuclassic.h
@@ -41,7 +41,7 @@
#include <linux/seqlock.h>

#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
-#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */
+#define RCU_SECONDS_TILL_STALL_CHECK ( (CONFIG_HZ / 100) * 3 * HZ) /* for rcp->jiffies_stall */
#define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ) /* for rcp->jiffies_stall */
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */


Folkert van Heusden

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