diff options
| author | Dongli Zhang <dongli.zhang@oracle.com> | 2019-03-27 18:36:34 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-10 17:52:09 +0200 |
| commit | c301c5d382dd7f47042bb7631bea70a02dab7b0f (patch) | |
| tree | 25f276d391398f86e963da28722bccf36dc721a5 /drivers/block | |
| parent | 684a9e97ba19bfde873f245f8bb198625f9d3ba5 (diff) | |
virtio-blk: limit number of hw queues by nr_cpu_ids
[ Upstream commit bf348f9b78d413e75bb079462751a1d86b6de36c ]
When tag_set->nr_maps is 1, the block layer limits the number of hw queues
by nr_cpu_ids. No matter how many hw queues are used by virtio-blk, as it
has (tag_set->nr_maps == 1), it can use at most nr_cpu_ids hw queues.
In addition, specifically for pci scenario, when the 'num-queues' specified
by qemu is more than maxcpus, virtio-blk would not be able to allocate more
than maxcpus vectors in order to have a vector for each queue. As a result,
it falls back into MSI-X with one vector for config and one shared for
queues.
Considering above reasons, this patch limits the number of hw queues used
by virtio-blk by nr_cpu_ids.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/virtio_blk.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 10332c24f961..44ef1d66caa6 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -392,6 +392,8 @@ static int init_vq(struct virtio_blk *vblk) if (err) num_vqs = 1; + num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs); + vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL); if (!vblk->vqs) return -ENOMEM; |