[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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

  • To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, "Tian, Kevin" <kevin.tian@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • From: "Graham, Simon" <Simon.Graham@xxxxxxxxxxx>
  • Date: Thu, 1 Feb 2007 22:47:08 -0500
  • Delivery-date: Thu, 01 Feb 2007 19:48:06 -0800
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>
  • Thread-topic: [Xen-devel] [PATCH] Fix softlockup issue after vcpu hotplug

> 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
> 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...


Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.