Re: [PATCH v1 0/2] virtio-mem: prepare for granularity smaller than MAX_ORDER - 1

[David Hildenbrand <david@redhat.com>]

On 29.11.21 17:47, Zi Yan wrote:
> On 26 Nov 2021, at 8:42, 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.
>>
>> 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@sent.com
> 
> The patchset looks good to me. Thanks. Reviewed-by: Zi Yan <ziy@nvidia.com>

Thanks a lot!

-- 
Thanks,

David / dhildenb