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author | Greg Kurz <groug@kaod.org> | 2021-04-07 16:34:59 +0200 |
---|---|---|
committer | Michael S. Tsirkin <mst@redhat.com> | 2021-05-14 10:26:18 -0400 |
commit | d0267da614890b8f817364ae25850cdbb580a569 (patch) | |
tree | 8b52e4c2cbf3443977f1dea1b94dd62f5bbf93cf /hw | |
parent | 570fe439e5d1b8626cf344c6bc97d90cfcaf0c79 (diff) | |
download | qemu-d0267da614890b8f817364ae25850cdbb580a569.zip qemu-d0267da614890b8f817364ae25850cdbb580a569.tar.gz qemu-d0267da614890b8f817364ae25850cdbb580a569.tar.bz2 |
virtio-blk: Configure all host notifiers in a single MR transaction
This allows the virtio-blk-pci device to batch the setup of all its
host notifiers. This significantly improves boot time of VMs with a
high number of vCPUs, e.g. from 3m26.186s down to 0m58.023s for a
pseries machine with 384 vCPUs.
Note that memory_region_transaction_commit() must be called before
virtio_bus_cleanup_host_notifier() because the latter might close
ioeventfds that the transaction still assumes to be around when it
commits.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210407143501.244343-3-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r-- | hw/block/dataplane/virtio-blk.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index d7b5c95..cd81893 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -198,19 +198,30 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev) goto fail_guest_notifiers; } + memory_region_transaction_begin(); + /* Set up virtqueue notify */ for (i = 0; i < nvqs; i++) { r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, true); if (r != 0) { + int j = i; + fprintf(stderr, "virtio-blk failed to set host notifier (%d)\n", r); while (i--) { virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); + } + + memory_region_transaction_commit(); + + while (j--) { virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); } goto fail_host_notifiers; } } + memory_region_transaction_commit(); + s->starting = false; vblk->dataplane_started = true; trace_virtio_blk_data_plane_start(s); @@ -246,8 +257,15 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev) return 0; fail_aio_context: + memory_region_transaction_begin(); + for (i = 0; i < nvqs; i++) { virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); + } + + memory_region_transaction_commit(); + + for (i = 0; i < nvqs; i++) { virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); } fail_host_notifiers: @@ -312,8 +330,15 @@ void virtio_blk_data_plane_stop(VirtIODevice *vdev) aio_context_release(s->ctx); + memory_region_transaction_begin(); + for (i = 0; i < nvqs; i++) { virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); + } + + memory_region_transaction_commit(); + + for (i = 0; i < nvqs; i++) { virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); } |