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vhost: track zero copy failures using DMA length 

This will be used to disable zerocopy when error rate
is high.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael S. Tsirkin 2012-11-01 09:16:42 +00:00 committed by David S. Miller
parent 70e4cb9aaf
commit c4fcb586c3
2 changed files with 8 additions and 3 deletions
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7
drivers/vhost/vhost.c
View File

@ -425,7 +425,7 @@ int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq)
int j = 0;
for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
if ((vq->heads[i].len == VHOST_DMA_DONE_LEN)) {
if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
vhost_add_used_and_signal(vq->dev, vq,
vq->heads[i].id, 0);
@ -1600,13 +1600,14 @@ void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs)
kfree(ubufs);
}
void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool status)
void vhost_zerocopy_callback(struct ubuf_info *ubuf, int status)
{
struct vhost_ubuf_ref *ubufs = ubuf->ctx;
struct vhost_virtqueue *vq = ubufs->vq;
vhost_poll_queue(&vq->poll);
/* set len to mark this desc buffers done DMA */
vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN;
vq->heads[ubuf->desc].len = status ?
VHOST_DMA_FAILED_LEN : VHOST_DMA_DONE_LEN;
kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
}

4
drivers/vhost/vhost.h
View File

@ -17,6 +17,8 @@
* For transmit, used buffer len is unused; we override it to track buffer
* status internally; used for zerocopy tx only.
*/
/* Lower device DMA failed */
#define VHOST_DMA_FAILED_LEN 3
/* Lower device DMA done */
#define VHOST_DMA_DONE_LEN 2
/* Lower device DMA in progress */
@ -24,6 +26,8 @@
/* Buffer unused */
#define VHOST_DMA_CLEAR_LEN 0
#define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN)
struct vhost_device;
struct vhost_work;