Re: [PATCH 1/1] virtio-blk-ccw: tweak the default for num_queues

[Halil Pasic]

On Wed, 11 Nov 2020 13:49:08 +0100
Michael Mueller <mimu@linux.ibm.com> wrote:

> Halil,
> 
> still I would like to know what the exact memory consumption per queue
> is that you are talking about. Have you made a calculation? Thanks.

Hi! 

The default size for virtio-blk seems to be 256 ring entries, which
translates to 6668 bytes for the split ring(s). The queue size is user
configurable, and guest, in theory, can decide to have a smaller queue.
The indirect descriptors are allocated separately, and bounced via
swiotlb in case of secure guests.

Regards,
Halil