Re: [PATCH] hung_task_timeout: configurable default

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 27 Apr 2011 14:27:24 -0400
Jeff Mahoney <jeffm@suse.com> wrote:

>  This patch allows the default value for sysctl_hung_task_timeout_secs
>  to be set at build time. The feature carries virtually no overhead,
>  so it makes sense to keep it enabled. On heavily loaded systems, though,
>  it can end up triggering stack traces when there is no bug other than
>  the system being underprovisioned. We use this patch to keep the hung task
>  facility available but disabled at boot-time.
> 
>  The default of 120 seconds is preserved. As a note, commit e162b39a may
>  have accidentally reverted commit fb822db4, which raised the default from
>  120 seconds to 480 seconds.

The changelog forgot to tell us why the patch's author considers the
patch to be needed.  This happens quite a lot.

> @@ -33,7 +33,8 @@ unsigned long __read_mostly sysctl_hung_
>  /*
>   * Zero means infinite timeout - no checking done:
>   */
> -unsigned long __read_mostly sysctl_hung_task_timeout_secs = 120;
> +unsigned long __read_mostly sysctl_hung_task_timeout_secs =
> +					CONFIG_DEFAULT_HUNG_TASK_TIMEOUT;
>  

For the life of me I can't understand why you distro guys need to keep
patching the kernel when you could just add a line to your initscripts.

I'm suspecting that lameness is involved.