On Thu, Jul 14, 2016 at 10:27:15AM +0200, Igor Mammedov wrote: > On Thu, 14 Jul 2016 10:51:27 +1000 > David Gibson <da...@gibson.dropbear.id.au> wrote: > > > On Wed, Jul 13, 2016 at 12:20:20PM +0530, Bharata B Rao wrote: > > > If CPU core addition or removal is allowed in random order leading to > > > holes in the core id range (and hence in the cpu_index range), migration > > > can fail as migration with holes in cpu_index range isn't yet handled > > > correctly. > > > > > > Prevent this situation by enforcing the addition in contiguous order > > > and removal in LIFO order so that we never end up with holes in > > > cpu_index range. > > > > > > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com> > > > --- > > > While there is work in progress to support migration when there are holes > > > in cpu_index range resulting from out-of-order plug or unplug, this patch > > > is intended as a last resort if no easy, risk-free and elegant solution > > > emerges before 2.7 dev cycle ends. > > > > Applied to ppc-for-2.7. We can revert it once the problems with > > cpu_index are sorted out. > You'd need to add machine type specific compat option here, > so that new-qemu -M 2.7 wouldn't allow out of order too and > could be migrated to old-qemu -M 2.7
Hmm, do we care about migration from newer back to older versions of
qemu upstream? If so, then I guess we do need this option. Though
strictly we don't need it until we actually do allow any-order
hotplug.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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