diff options
author | Stefan Hajnoczi <stefanha@redhat.com> | 2020-10-01 15:46:03 +0100 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2020-10-23 13:42:16 +0100 |
commit | d9b495f9c6a943c9bbd50f7469efb645c23009c3 (patch) | |
tree | d8ca95db872445d606fbe7eaa5577e99fa74d925 /block/export | |
parent | f51d23c80af73c95e0ce703ad06a300f1b3d63ef (diff) |
block/export: add vhost-user-blk multi-queue support
Allow the number of queues to be configured using --export
vhost-user-blk,num-queues=N. This setting should match the QEMU --device
vhost-user-blk-pci,num-queues=N setting but QEMU vhost-user-blk.c lowers
its own value if the vhost-user-blk backend offers fewer queues than
QEMU.
The vhost-user-blk-server.c code is already capable of multi-queue. All
virtqueue processing runs in the same AioContext. No new locking is
needed.
Add the num-queues=N option and set the VIRTIO_BLK_F_MQ feature bit.
Note that the feature bit only announces the presence of the num_queues
configuration space field. It does not promise that there is more than 1
virtqueue, so we can set it unconditionally.
I tested multi-queue by running a random read fio test with numjobs=4 on
an -smp 4 guest. After the benchmark finished the guest /proc/interrupts
file showed activity on all 4 virtio-blk MSI-X. The /sys/block/vda/mq/
directory shows that Linux blk-mq has 4 queues configured.
An automated test is included in the next commit.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20201001144604.559733-2-stefanha@redhat.com
[Fixed accidental tab characters as suggested by Markus Armbruster
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/export')
-rw-r--r-- | block/export/vhost-user-blk-server.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c index 286eb5fb9a..41f4933d6e 100644 --- a/block/export/vhost-user-blk-server.c +++ b/block/export/vhost-user-blk-server.c @@ -21,7 +21,7 @@ #include "util/block-helpers.h" enum { - VHOST_USER_BLK_MAX_QUEUES = 1, + VHOST_USER_BLK_NUM_QUEUES_DEFAULT = 1, }; struct virtio_blk_inhdr { unsigned char status; @@ -242,6 +242,7 @@ static uint64_t vu_blk_get_features(VuDev *dev) 1ull << VIRTIO_BLK_F_DISCARD | 1ull << VIRTIO_BLK_F_WRITE_ZEROES | 1ull << VIRTIO_BLK_F_CONFIG_WCE | + 1ull << VIRTIO_BLK_F_MQ | 1ull << VIRTIO_F_VERSION_1 | 1ull << VIRTIO_RING_F_INDIRECT_DESC | 1ull << VIRTIO_RING_F_EVENT_IDX | @@ -338,7 +339,9 @@ static void blk_aio_detach(void *opaque) static void vu_blk_initialize_config(BlockDriverState *bs, - struct virtio_blk_config *config, uint32_t blk_size) + struct virtio_blk_config *config, + uint32_t blk_size, + uint16_t num_queues) { config->capacity = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; config->blk_size = blk_size; @@ -346,7 +349,7 @@ vu_blk_initialize_config(BlockDriverState *bs, config->seg_max = 128 - 2; config->min_io_size = 1; config->opt_io_size = 1; - config->num_queues = VHOST_USER_BLK_MAX_QUEUES; + config->num_queues = num_queues; config->max_discard_sectors = 32768; config->max_discard_seg = 1; config->discard_sector_alignment = config->blk_size >> 9; @@ -368,6 +371,7 @@ static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts, BlockExportOptionsVhostUserBlk *vu_opts = &opts->u.vhost_user_blk; Error *local_err = NULL; uint64_t logical_block_size; + uint16_t num_queues = VHOST_USER_BLK_NUM_QUEUES_DEFAULT; vexp->writable = opts->writable; vexp->blkcfg.wce = 0; @@ -385,15 +389,23 @@ static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts, } vexp->blk_size = logical_block_size; blk_set_guest_block_size(exp->blk, logical_block_size); + + if (vu_opts->has_num_queues) { + num_queues = vu_opts->num_queues; + } + if (num_queues == 0) { + error_setg(errp, "num-queues must be greater than 0"); + return -EINVAL; + } + vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg, - logical_block_size); + logical_block_size, num_queues); blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach, vexp); if (!vhost_user_server_start(&vexp->vu_server, vu_opts->addr, exp->ctx, - VHOST_USER_BLK_MAX_QUEUES, &vu_blk_iface, - errp)) { + num_queues, &vu_blk_iface, errp)) { blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach, vexp); return -EADDRNOTAVAIL; |