Hi Mike,
On Tue, Jan 29, 2013 at 05:42:43PM +0400, Mike Lykov wrote:
>
> So my questions:
>
> 1. Are there a BUG in soft lockup detection mechanizm? Changing
> watchdog_thresh to 30 have a side effect in production - D-state
> userspace processes will be detected slowly. Are there a need to
> detecting soft lockups at boot time? Maybe it need after initramfs
> boot only when userspace processes begin to work?
The softlockup mechanism works scheduling a high priority task that kicks
the softlockups. If the unzip thread is taking too long, it could
accidentally trip the detection.
Seeing that you are running on a 600 MHz machine, it could be possible.
Though I am not entirely sure how the scheduling works for decompressing
the initramfs. I wouldn't think it is that high of a priority.
>
> 2. How to change watchdog_thresh parameter at boot without patching
> sources? If it necessary (with it side effects) maybe implement it
> as commandline parameter or config compile time parameter?
I attached a patch below that allows you to set it a boot time. Let me
know if this works for you, then I can clean it up and post it properly.
Cheers,
Don
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 75a2ab3..e448d63 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -79,6 +79,14 @@ static int __init softlockup_panic_setup(char *str)
}
__setup("softlockup_panic=", softlockup_panic_setup);
+static int __init watchdog_thresh_setup(char *str)
+{
+ watchdog_thresh = simple_strtoul(str, NULL, 0);
+
+ return 1;
+}
+__setup("watchdog_thresh=", watchdog_thresh_setup);
+
static int __init nowatchdog_setup(char *str)
{
watchdog_enabled = 0;
--
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