RE: [Xen-devel] [PATCH] Fix softlockup issue after vcpu hotplug

["Graham, Simon" <Simon.Graham@xxxxxxxxxxx>]

> 
> I don't mean to touch it only every 5s in the loop, I mean to touch it
> every
> time round the loop but only if stolen is greater than five seconds:
> 

Ah right -- got it now; good point.

> The only theoretical problem with this approach is if you got time
> stolen
> that accumulated to more than five seconds, but this happened in two
or
> more
> bursts, back-to-back. Then no one stolen period would be enough to
> trigger
> the touch, but also the guest may not be running for long enough to
> schedule
> the softlockup thread. I really don't believe this would be an issue
> ever in
> practise however, given sane scheduling parameters and load on the
> system.
> If the system were loaded/configured so it could happen, the guest
> would be
> in dire straits for other reasons.

How about using a slightly smaller value like 1 or 2 s -- something
larger than the expected wakeup latency etc but small enough that it
would take multiple back-to-back bursts to hit 10s...

Simon

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