On 3/27/19 4:36 AM, Dongli Zhang wrote: > 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 use by > virtio-blk/virtio-scsi, as they both have (tag_set->nr_maps == 1), they > 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/virtio-scsi would not be able to > allocate more than maxcpus vectors in order to have a vector for each > queue. As a result, they fall back into MSI-X with one vector for config > and one shared for queues. > > Considering above reasons, this patch set limits the number of hw queues > used by nr_cpu_ids for both virtio-blk and virtio-scsi. I picked both up for 5.1. -- Jens Axboe
