On Thu, Nov 09, 2023 at 10:23:28PM +0800, Kunkun Jiang wrote:
From: Dongli Zhang dongli.zhang@oracle.com
[ Upstream commit 1978f30a87732d4d9072a20abeded9fe17884f1b ]
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-scsi, 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-scsi 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-scsi 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: Kunkun Jiang jiangkunkun@huawei.com
drivers/scsi/virtio_scsi.c | 1 + 1 file changed, 1 insertion(+)
Both now queued up, thanks.
greg k-h