On Fri, Nov 26, 2021 at 02:42:07PM +0100, David Hildenbrand wrote: > 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? > Tested with ZONE_MOVABLE after removing the MAX_ORDER - 1 granularity > limitation in virtio-mem, and using different device block sizes (2MiB, > 4MiB, 8MiB). > > [1] https://lkml.kernel.org/r/20211115193725.737539-1-zi.yan@xxxxxxxx > > Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> > Cc: Jason Wang <jasowang@xxxxxxxxxx> > Cc: Zi Yan <ziy@xxxxxxxxxx> > Cc: Gavin Shan <gshan@xxxxxxxxxx> > Cc: Hui Zhu <teawater@xxxxxxxxx> > Cc: Eric Ren <renzhengeek@xxxxxxxxx> > Cc: Sebastien Boeuf <sebastien.boeuf@xxxxxxxxx> > Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx> > Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> > Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx > Cc: linux-mm@xxxxxxxxx > > David Hildenbrand (2): > virtio-mem: prepare page onlining code for granularity smaller than > MAX_ORDER - 1 > virtio-mem: prepare fake page onlining code for granularity smaller > than MAX_ORDER - 1 > > drivers/virtio/virtio_mem.c | 110 ++++++++++++++++++++++++------------ > 1 file changed, 74 insertions(+), 36 deletions(-) > > -- > 2.31.1
