Re: Increased memory usage with scsi-mq

From: Paolo Bonzini
Date: Wed Aug 09 2017 - 12:50:19 EST


On 09/08/2017 18:01, Christoph Hellwig wrote:
> On Mon, Aug 07, 2017 at 03:07:48PM +0200, Paolo Bonzini wrote:
>> can_queue should depend on the virtqueue size, which unfortunately can
>> vary for each virtio-scsi device in theory. The virtqueue size is
>> retrieved by drivers/virtio prior to calling vring_create_virtqueue, and
>> in QEMU it is the second argument to virtio_add_queue.
>
> Why is that unfortunate? We don't even have to set can_queue in
> the host template, we can dynamically set it on per-host basis.

Ah, cool, I thought allocations based on can_queue happened already in
scsi_host_alloc, but they happen at scsi_add_host time.

Paolo