Re: [PATCH 2/4] [RFC] virtio: Introduce new API to get free space
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2011-05-04 19:58:18
Also in:
kvm
On Wed, May 04, 2011 at 07:33:19PM +0530, Krishna Kumar wrote:
quoted hunk ↗ jump to hunk
@@ -185,11 +193,6 @@ int virtqueue_add_buf_gfp(struct virtque if (vq->num_free < out + in) { pr_debug("Can't add buf len %i - avail = %i\n", out + in, vq->num_free); - /* FIXME: for historical reasons, we force a notify here if - * there are outgoing parts to the buffer. Presumably the - * host should service the ring ASAP. */ - if (out) - vq->notify(&vq->vq); END_USE(vq); return -ENOSPC; }
I thought about it some more. We should typically not get into this state with the current driver as we check capacity upfront. So why would this change help performance? Shirley, any idea? -- MST