Re: [PATCH V5 4/5] virtio-scsi: introduce multiqueue support

From: Venkatesh Srinivas
Date: Tue Mar 19 2013 - 21:47:09 EST

This looks pretty good!

I rather like the (lack of) locking in I/O completion (around the req
count vs. target/queue binding). It is unfortunate that you need to hold the per-target lock in virtscsi_pick_vq() though; have any idea
how much that lock hurts?

Just two minor comments:

(in struct virtio_scsi_target_data):
+ /* This spinlock never help at the same time as vq_lock. */
^^^^ held?

(in struct virtio_scsi):
+ /* Does the affinity hint is set for virtqueues? */
Could you rephrase that, please?

Tested on qemu and w/ Google Compute Engine's virtio-scsi device.

Reviewed-and-tested-by: Venkatesh Srinivas <venkateshs@xxxxxxxxxx>

-- vs;
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