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* [PATCH] virtio_ring: remove unnecessary to_vvq call in vring hot path
@ 2022-03-24  7:33 Xianting Tian
  2022-03-28  9:05 ` Stefano Garzarella
  0 siblings, 1 reply; 5+ messages in thread
From: Xianting Tian @ 2022-03-24  7:33 UTC (permalink / raw)
  To: mst, jasowang; +Cc: virtualization, linux-kernel, Xianting Tian

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.

Other tiny optimization:
Add unlikely to "if (vq->vq.num_free < descs_used).

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
---
 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


^ permalink raw reply	[flat|nested] 5+ messages in thread
* [PATCH] virtio_ring: remove unnecessary to_vvq call in vring hot path
@ 2022-06-22  8:51 Deming Wang
  0 siblings, 0 replies; 5+ messages in thread
From: Deming Wang @ 2022-06-22  8:51 UTC (permalink / raw)
  To: mst, jasowang; +Cc: virtualization, linux-kernel, Deming Wang

It passes '_vq' to virtqueue_enable_cb_delayed_packed(), which
still calls to_vvq to get 'vq', let's directly pass
to_vvq to gunnecessary call of to_vvq in hot path.

Signed-off-by: Deming Wang <wangdeming@inspur.com>
---
 drivers/virtio/virtio_ring.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 13a7348cedff..4d41d5a90816 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1534,9 +1534,8 @@ static bool virtqueue_poll_packed(struct virtqueue *_vq, u16 off_wrap)
 	return is_used_desc_packed(vq, used_idx, wrap_counter);
 }
 
-static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq)
+static bool virtqueue_enable_cb_delayed_packed(struct vring_virtqueue *vq)
 {
-	struct vring_virtqueue *vq = to_vvq(_vq);
 	u16 used_idx, wrap_counter;
 	u16 bufs;
 
@@ -2098,7 +2097,7 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
 	if (vq->event_triggered)
 		vq->event_triggered = false;
 
-	return vq->packed_ring ? virtqueue_enable_cb_delayed_packed(_vq) :
+	return vq->packed_ring ? virtqueue_enable_cb_delayed_packed(vq) :
 				 virtqueue_enable_cb_delayed_split(_vq);
 }
 EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed);
-- 
2.27.0


^ permalink raw reply	[flat|nested] 5+ messages in thread
* [PATCH] virtio_ring: remove unnecessary to_vvq call in vring hot path
@ 2022-06-22  9:09 Deming Wang
  0 siblings, 0 replies; 5+ messages in thread
From: Deming Wang @ 2022-06-22  9:09 UTC (permalink / raw)
  To: mst, jasowang; +Cc: virtualization, linux-kernel, Deming Wang

It passes '_vq' to virtqueue_detach_unused_buf_packed(),
which still calls to_vvq to get 'vq', let's directly
pass 'vq'. It can avoid unnecessary call of to_vvq in hot path.

Signed-off-by: Deming Wang <wangdeming@inspur.com>
---
 drivers/virtio/virtio_ring.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 13a7348cedff..905d003f6849 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1593,9 +1593,8 @@ static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq)
 	return true;
 }
 
-static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq)
+static void *virtqueue_detach_unused_buf_packed(struct vring_virtqueue *vq)
 {
-	struct vring_virtqueue *vq = to_vvq(_vq);
 	unsigned int i;
 	void *buf;
 
@@ -2115,7 +2114,7 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
-	return vq->packed_ring ? virtqueue_detach_unused_buf_packed(_vq) :
+	return vq->packed_ring ? virtqueue_detach_unused_buf_packed(vq) :
 				 virtqueue_detach_unused_buf_split(_vq);
 }
 EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf);
-- 
2.27.0


^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-06-22  9:11 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-24  7:33 [PATCH] virtio_ring: remove unnecessary to_vvq call in vring hot path Xianting Tian
2022-03-28  9:05 ` Stefano Garzarella
2022-03-28  9:13   ` Xianting Tian
2022-06-22  8:51 Deming Wang
2022-06-22  9:09 Deming Wang

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