[Qemu-devel] [PATCH v2 0/8] virtio-blk: multiqueue support

[Stefan Hajnoczi <stefanha@redhat.com>]

v2:
 * Simplify s->rq live migration [Paolo]
 * Use more efficient bitmap ops for batch notification [Paolo]
 * Fix perf regression due to batch notify BH in wrong AioContext [Christian]

The virtio_blk guest driver has supported multiple virtqueues since Linux 3.17.
This patch series adds multiple virtqueues to QEMU's virtio-blk emulated
device.

Ming Lei sent patches previously but these were not merged.  This series
implements virtio-blk multiqueue for QEMU from scratch since the codebase has
changed.  Live migration support for s->rq was also missing from the previous
series and has been added.

It's important to note that QEMU's block layer does not support multiqueue yet.
Therefore virtio-blk device processes all virtqueues in the same AioContext
(IOThread).  Further work is necessary to take advantage of multiqueue support
in QEMU's block layer once it becomes available.

I will post performance results once they are ready.

Stefan Hajnoczi (8):
  virtio-blk: use batch notify in non-dataplane case
  virtio-blk: tell dataplane which vq to notify
  virtio-blk: associate request with a virtqueue
  virtio-blk: add VirtIOBlockConf->num_queues
  virtio-blk: multiqueue batch notify
  virtio-blk: live migrateion s->rq with multiqueue
  virtio-blk: dataplane multiqueue support
  virtio-blk: add num-queues device property

 hw/block/dataplane/virtio-blk.c |  68 +++++++++++----------
 hw/block/dataplane/virtio-blk.h |   2 +-
 hw/block/virtio-blk.c           | 129 +++++++++++++++++++++++++++++++++++-----
 include/hw/virtio/virtio-blk.h  |   8 ++-
 4 files changed, 159 insertions(+), 48 deletions(-)

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2.5.5