WD_PASSIVE kernel based tickling of the watchdog - request for ideas
Nick Hibma
nick at van-laarhoven.org
Fri Dec 15 14:16:22 PST 2006
I've got two requests for a clue ... er... ideas today on how to
implement the WD_PASSIVE flag in the watchdog(9) interface:
- How would I best implement the tickling of the watchdog at specified
intervals (e.g. 1/2 the watchdog timeout value)?
By using a
- timeout
- kernel thread sleeping most of the time
- hardclock()
considering the trade-off between large variance in frequency vs. making
sure we notice a (permanent) freeze in the kernel somewhere. For example
burning a CD sometimes makes my laptop freeze for a short period. Will
the watchdog fire in that case?
- What do we consider a 'bad' situation in which the watchdog should not
be tickled? What kind of checks would we need to perform?
I'd be interested to hear your thoughts.
Nick
P.S.: I'm personally not interested in passive tickling of the watchdog,
so if there is no response, I'll leave the implementation as is (return
EOPNOTSUPP at the moment).
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