Re: [PATCH v2 00/29] virtio-mem: Big Block Mode (BBM)

Michael S. Tsirkin
2020-11-18T09:01:24Z

On Thu, Nov 12, 2020 at 02:37:46PM +0100, David Hildenbrand wrote:
> @Andrew, can we have an ack for patch #27, so that one can go via
> the vhost tree for 5.11?

OK, we got an ack, I'll put it in next now.
Thanks!

> ---
>
> virtio-mem currently only supports device block sizes that span at most
> a single Linux memory block. For example, gigantic pages in the hypervisor
> result on x86-64 in a device block size of 1 GiB - when the Linux memory
> block size is 128 MiB, we cannot support such devices (we fail loading the
> driver). Of course, we want to support any device block size in any Linux
> VM.
>
> Bigger device block sizes will become especially important once supporting
> VFIO in QEMU - each device block has to be mapped separately, and the
> maximum number of mappings for VFIO is 64k. So we usually want blocks in
> the gigabyte range when wanting to grow the VM big.
>
> Patch #1 - #10 are cleanups and optimizations
> Patch #11 - #24 are refactorings to prepare for BBM
> Patch #25 - #29 implement BBM, including one mm/memory_hotplug extension
>
> This series is based on latest linus/master and can be found at:
> git@github.com:davidhildenbrand/linux.git virtio-mem-bbm-v2
>
> v1 -> v2:
> - Code wise, the only bigger change is using an union for sbm/bbm state
> - Reworked some subjects/patch descriptions
> - Reshuffled patches to make reviweing easier, and to have
> cleanups+optimizations before all refactorings
> - "virtio-mem: more precise calculation in
> virtio_mem_mb_state_prepare_next_mb()"
> -- Changed subject
> -- Avoid two local variables
>
> David Hildenbrand (29):
> virtio-mem: determine nid only once using memory_add_physaddr_to_nid()
> virtio-mem: more precise calculation in
> virtio_mem_mb_state_prepare_next_mb()
> virtio-mem: simplify MAX_ORDER - 1 / pageblock_order handling
> virtio-mem: drop rc2 in virtio_mem_mb_plug_and_add()
> virtio-mem: use "unsigned long" for nr_pages when fake
> onlining/offlining
> virtio-mem: factor out calculation of the bit number within the
> subblock bitmap
> virtio-mem: print debug messages from virtio_mem_send_*_request()
> virtio-mem: factor out fake-offlining into virtio_mem_fake_offline()
> virtio-mem: factor out handling of fake-offline pages in memory
> notifier
> virtio-mem: retry fake-offlining via alloc_contig_range() on
> ZONE_MOVABLE
> virtio-mem: generalize check for added memory
> virtio-mem: generalize virtio_mem_owned_mb()
> virtio-mem: generalize virtio_mem_overlaps_range()
> virtio-mem: drop last_mb_id
> virtio-mem: don't always trigger the workqueue when offlining memory
> virtio-mem: generalize handling when memory is getting onlined
> deferred
> virito-mem: document Sub Block Mode (SBM)
> virtio-mem: memory block states are specific to Sub Block Mode (SBM)
> virito-mem: subblock states are specific to Sub Block Mode (SBM)
> virtio-mem: nb_sb_per_mb and subblock_size are specific to Sub Block
> Mode (SBM)
> virtio-mem: memory block ids are specific to Sub Block Mode (SBM)
> virito-mem: existing (un)plug functions are specific to Sub Block Mode
> (SBM)
> virtio-mem: memory notifier callbacks are specific to Sub Block Mode
> (SBM)
> virtio-mem: factor out adding/removing memory from Linux
> virtio-mem: Big Block Mode (BBM) memory hotplug
> virtio-mem: allow to force Big Block Mode (BBM) and set the big block
> size
> mm/memory_hotplug: extend offline_and_remove_memory() to handle more
> than one memory block
> virtio-mem: Big Block Mode (BBM) - basic memory hotunplug
> virtio-mem: Big Block Mode (BBM) - safe memory hotunplug
>
> drivers/virtio/virtio_mem.c | 1789 +++++++++++++++++++++++++----------
> mm/memory_hotplug.c | 105 +-
> 2 files changed, 1376 insertions(+), 518 deletions(-)
>
> --
> 2.26.2