On Thu, Mar 24, 2022 at 03:33:40PM +0800, Xianting Tian wrote:
It passes '_vq' to virtqueue_use_indirect(), which still calls
to_vvq to get 'vq', let's directly pass 'vq'. It can avoid
unnecessary call of to_vvq in hot path.
It seems reasonable to me.
Other tiny optimization:
Add unlikely to "if (vq->vq.num_free < descs_used).
Better to do this change in another patch.
Thanks,
Stefano
Signed-off-by: Xianting Tian <xianting.tian@xxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_ring.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 962f1477b1fa..ab6d5f0cb579 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -205,11 +205,9 @@ struct vring_virtqueue {
#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
-static inline bool virtqueue_use_indirect(struct virtqueue *_vq,
+static inline bool virtqueue_use_indirect(struct vring_virtqueue *vq,
unsigned int total_sg)
{
- struct vring_virtqueue *vq = to_vvq(_vq);
-
/*
* If the host supports indirect descriptor tables, and we have multiple
* buffers, then go indirect. FIXME: tune this threshold
@@ -507,7 +505,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
head = vq->free_head;
- if (virtqueue_use_indirect(_vq, total_sg))
+ if (virtqueue_use_indirect(vq, total_sg))
desc = alloc_indirect_split(_vq, total_sg, gfp);
else {
desc = NULL;
@@ -527,7 +525,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
descs_used = total_sg;
}
- if (vq->vq.num_free < descs_used) {
+ if (unlikely(vq->vq.num_free < descs_used)) {
pr_debug("Can't add buf len %i - avail = %i\n",
descs_used, vq->vq.num_free);
/* FIXME: for historical reasons, we force a notify here if
@@ -1194,7 +1192,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
BUG_ON(total_sg == 0);
- if (virtqueue_use_indirect(_vq, total_sg)) {
+ if (virtqueue_use_indirect(vq, total_sg)) {
err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs,
in_sgs, data, gfp);
if (err != -ENOMEM) {
--
2.17.1
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