On Thu, 21 Jul 2016 23:07:06 +1000 David Gibson <da...@gibson.dropbear.id.au> wrote:
> On Wed, Jul 20, 2016 at 09:01:11AM +0200, Peter Krempa wrote: > > On Wed, Jul 20, 2016 at 11:00:05 +1000, David Gibson wrote: > > > On Tue, Jul 19, 2016 at 01:52:40PM +0200, Peter Krempa wrote: > > > > On Mon, Jul 18, 2016 at 19:19:19 +1000, David Gibson wrote: > > > > > The spapr implementation of query-hotpluggable-cpus builds the list of > > > > > hotpluggable cores from the end (most removed from the list head) > > > > > because that's the easiest way with a singly linked list. Because it > > > > > also traverses the possible CPU cores starting from low indexes the > > > > > resulting list has the cpu cores listed in reverse order by core-id. > > > > > > > > > > That's not generally harmful, but it means the output from "info > > > > > hotpluggable-cpus" is a little harder to read than it could be. > > > > > > > > > > Therefore, traverse the cpus in reverse order so that the final list > > > > > ends up in increasing-core-id order. > > > > > > > > To make this interface usable with in-order hotplug the ordering of the > > > > entries should be codified in the schema documentation. (see my response > > > > on the cover letter for justification). > > > > > > I'm not really sure what you mean by this. > > > > Currently the order of entries in reply of query-hotpluggable-cpus is > > arbitrary as this patch hints. > > > > If qemu won't support arbitrary order hotplug but libvirt should be able > > to use the new interface, then the order of replies of > > query-hotpluggable-cpus need to corelate (in a documented fashion) with > > the order we need to plug the cpus in. By not documenting any order > > libvirt can just guess it (by reimplementing the algorithm in qemu). > > > I've pointed this out in a sub-thread of the cover-letter. > > Right, that's kind of the point of this patch - it makes the order > returned by query-hotpluggable-cpus match the required order for "in > order" hotplug. That may not be necessary so - it looks like between > Igor and myself we might have an eleventh hour way of enabling > any-order hotplug. > > That said, I'm still inclined to push this patch at some point for the > sake of easier to read debugging output. it's qmp command output intended for machine parsing, so don't really need it
