Re: [RFC v2 2/7] vhost_test: batch used buffer

Only add to used ring when a batch of buffer have all been used.  And if
in order feature negotiated, only add the last used descriptor for a
batch of buffer.

Signed-off-by: Guo Zhi <redacted>
---
 drivers/vhost/test.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
index bc8e7fb1e635..57cdb3a3edf6 100644
--- a/drivers/vhost/test.c
+++ b/drivers/vhost/test.c

@@ -43,6 +43,9 @@ struct vhost_test {
 static void handle_vq(struct vhost_test *n)
 {
        struct vhost_virtqueue *vq = &n->vqs[VHOST_TEST_VQ];
+       struct vring_used_elem *heads = kmalloc(sizeof(*heads)
+                       * vq->num, GFP_KERNEL);

+       int batch_idx = 0;
        unsigned out, in;
        int head;
        size_t len, total_len = 0;

@@ -84,11 +87,14 @@ static void handle_vq(struct vhost_test *n)
                        vq_err(vq, "Unexpected 0 len for TX\n");
                        break;
                }
-               vhost_add_used_and_signal(&n->dev, vq, head, 0);
+               heads[batch_idx].id = cpu_to_vhost32(vq, head);
+               heads[batch_idx++].len = cpu_to_vhost32(vq, len);
                total_len += len;
                if (unlikely(vhost_exceeds_weight(vq, 0, total_len)))
                        break;
        }
+       if (batch_idx)
+               vhost_add_used_and_signal_n(&n->dev, vq, heads, batch_idx);

        mutex_unlock(&vq->mutex);
 }
--

2.17.1