On 01.12.21 00:56, Michael S. Tsirkin wrote:

On Fri, Nov 26, 2021 at 02:42:07PM +0100, David Hildenbrand wrote:

quoted

The virtio-mem driver currently supports logical hot(un)plug in
MAX_ORDER - 1 granularity (4MiB on x86-64) or bigger. We want to support
pageblock granularity (2MiB on x86-64), to make hot(un)plug even more
flexible, and to improve hotunplug when using ZONE_NORMAL.

With pageblock granularity, we then have a granularity comparable to
hugepage ballooning. Further, there are ideas to increase MAX_ORDER, so
we really want to decouple it from MAX_ORDER.

While ZONE_MOVABLE should mostly work already, alloc_contig_range() still
needs work to be able to properly handle pageblock granularity on
ZONE_NORMAL. This support is in the works [1], so let's prepare
virtio-mem for supporting smaller granularity than MAX_ORDER - 1.

is there value to merging this seprately? or should this just
be part of that patchset?

The value would be to give it additional testing ahead of time. But we
could just carry it along. Whatever you prefer. (I'd suggest merging it
right away)

-- 
Thanks,

David / dhildenb