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Commit c4fcb586 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by David S. Miller
Browse files

vhost: track zero copy failures using DMA length 



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

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 70e4cb9a

drivers/vhost/vhost.c

+4 −3
Original line number Diff line number Diff line
@@ -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);

}

drivers/vhost/vhost.h

+4 −0
Original line number Diff line number Diff line
@@ -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;