watchdog end-user interface

[Andriy Gapon]

On 20/10/2016 00:47, Ngie Cooper wrote:
> On Wed, Oct 19, 2016 at 2:32 PM, Alfred Perlstein <alfred at freebsd.org> wrote:
> ...
>> Please look at the Linux interface for watchdogs, it is pretty good and
>> could/should be ported to us.
> 
> We (Isilon) also have a software watchdog implementation (in lieu of
> IPMI+watchdogd) to make sure "userspace processes are making
> progress".

Please tell me more about this.  It seems that there could be different
definitions of 'software watchdog' and different expectations of what it should do.

For example, we have SW_WATCHDOG in the tree for ages.
It's a watchdog driver that's driver by clock interrupts and its logic is
implemented in software.  In the current implementation there is only one
timeout action - a panic.

Not too long ago Alfred added another software watchdog that's driven by
callout-s.  To me it's quite alike to SW_WATCHDOG, but it has configurable
timeout actions: printf, log, panic, debugger.

So, I wonder how Isilon's software watchdog is different from the above two.


-- 
Andriy Gapon