diff mbox series

virtio: Introduce a new kick interface virtqueue_kick_try()

Message ID 20210519114757.6143-1-xuanzhuo@linux.alibaba.com
State New
Headers show
Series virtio: Introduce a new kick interface virtqueue_kick_try() | expand

Commit Message

Xuan Zhuo May 19, 2021, 11:47 a.m. UTC
Unlike virtqueue_kick(), virtqueue_kick_try() returns true only when the
kick is successful. In virtio-net, we want to count the number of kicks.
So we need an interface that can perceive whether the kick is actually
executed.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c     |  8 ++++----
 drivers/virtio/virtio_ring.c | 20 ++++++++++++++++++++
 include/linux/virtio.h       |  2 ++
 3 files changed, 26 insertions(+), 4 deletions(-)

Comments

Michael S. Tsirkin May 19, 2021, 12:44 p.m. UTC | #1
On Wed, May 19, 2021 at 07:47:57PM +0800, Xuan Zhuo wrote:
> Unlike virtqueue_kick(), virtqueue_kick_try() returns true only when the
> kick is successful. In virtio-net, we want to count the number of kicks.
> So we need an interface that can perceive whether the kick is actually
> executed.
> 
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
>  drivers/net/virtio_net.c     |  8 ++++----
>  drivers/virtio/virtio_ring.c | 20 ++++++++++++++++++++
>  include/linux/virtio.h       |  2 ++
>  3 files changed, 26 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 9b6a4a875c55..167697030cb6 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -617,7 +617,7 @@ static int virtnet_xdp_xmit(struct net_device *dev,
>  	ret = nxmit;
>  
>  	if (flags & XDP_XMIT_FLUSH) {
> -		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
> +		if (virtqueue_kick_try(sq->vq))
>  			kicks = 1;
>  	}
>  out:
> @@ -1325,7 +1325,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
>  		if (err)
>  			break;
>  	} while (rq->vq->num_free);
> -	if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {
> +	if (virtqueue_kick_try(rq->vq)) {
>  		unsigned long flags;
>  
>  		flags = u64_stats_update_begin_irqsave(&rq->stats.syncp);
> @@ -1533,7 +1533,7 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
>  
>  	if (xdp_xmit & VIRTIO_XDP_TX) {
>  		sq = virtnet_xdp_get_sq(vi);
> -		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
> +		if (virtqueue_kick_try(sq->vq)) {
>  			u64_stats_update_begin(&sq->stats.syncp);
>  			sq->stats.kicks++;
>  			u64_stats_update_end(&sq->stats.syncp);
> @@ -1710,7 +1710,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
>  	}
>  
>  	if (kick || netif_xmit_stopped(txq)) {
> -		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
> +		if (virtqueue_kick_try(sq->vq)) {
>  			u64_stats_update_begin(&sq->stats.syncp);
>  			sq->stats.kicks++;
>  			u64_stats_update_end(&sq->stats.syncp);
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 71e16b53e9c1..1462be756875 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -1874,6 +1874,26 @@ bool virtqueue_kick(struct virtqueue *vq)
>  }
>  EXPORT_SYMBOL_GPL(virtqueue_kick);
>  
> +/**
> + * virtqueue_kick_try - try update after add_buf
> + * @vq: the struct virtqueue
> + *
> + * After one or more virtqueue_add_* calls, invoke this to kick
> + * the other side.
> + *
> + * Caller must ensure we don't call this with other virtqueue
> + * operations at the same time (except where noted).
> + *
> + * Returns true if kick success, otherwise false.

so what is the difference between this and virtqueue_kick
which says

 * Returns false if kick failed, otherwise true.







> + */
> +bool virtqueue_kick_try(struct virtqueue *vq)
> +{
> +	if (virtqueue_kick_prepare(vq) && virtqueue_notify(vq))
> +		return true;
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(virtqueue_kick_try);
> +
>  /**
>   * virtqueue_get_buf - get the next used buffer
>   * @_vq: the struct virtqueue we're talking about.
> diff --git a/include/linux/virtio.h b/include/linux/virtio.h
> index b1894e0323fa..45cd6a0af24d 100644
> --- a/include/linux/virtio.h
> +++ b/include/linux/virtio.h
> @@ -59,6 +59,8 @@ int virtqueue_add_sgs(struct virtqueue *vq,
>  
>  bool virtqueue_kick(struct virtqueue *vq);
>  
> +bool virtqueue_kick_try(struct virtqueue *vq);
> +
>  bool virtqueue_kick_prepare(struct virtqueue *vq);
>  
>  bool virtqueue_notify(struct virtqueue *vq);
> -- 
> 2.31.0
Jason Wang May 31, 2021, 6:34 a.m. UTC | #2
在 2021/5/19 下午7:47, Xuan Zhuo 写道:
> Unlike virtqueue_kick(), virtqueue_kick_try() returns true only when the

> kick is successful. In virtio-net, we want to count the number of kicks.

> So we need an interface that can perceive whether the kick is actually

> executed.

>

> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>



Acked-by: Jason Wang <jasowang@redhat.com>


Thanks


> ---

>   drivers/net/virtio_net.c     |  8 ++++----

>   drivers/virtio/virtio_ring.c | 20 ++++++++++++++++++++

>   include/linux/virtio.h       |  2 ++

>   3 files changed, 26 insertions(+), 4 deletions(-)

>

> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c

> index 9b6a4a875c55..167697030cb6 100644

> --- a/drivers/net/virtio_net.c

> +++ b/drivers/net/virtio_net.c

> @@ -617,7 +617,7 @@ static int virtnet_xdp_xmit(struct net_device *dev,

>   	ret = nxmit;

>   

>   	if (flags & XDP_XMIT_FLUSH) {

> -		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))

> +		if (virtqueue_kick_try(sq->vq))

>   			kicks = 1;

>   	}

>   out:

> @@ -1325,7 +1325,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,

>   		if (err)

>   			break;

>   	} while (rq->vq->num_free);

> -	if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {

> +	if (virtqueue_kick_try(rq->vq)) {

>   		unsigned long flags;

>   

>   		flags = u64_stats_update_begin_irqsave(&rq->stats.syncp);

> @@ -1533,7 +1533,7 @@ static int virtnet_poll(struct napi_struct *napi, int budget)

>   

>   	if (xdp_xmit & VIRTIO_XDP_TX) {

>   		sq = virtnet_xdp_get_sq(vi);

> -		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {

> +		if (virtqueue_kick_try(sq->vq)) {

>   			u64_stats_update_begin(&sq->stats.syncp);

>   			sq->stats.kicks++;

>   			u64_stats_update_end(&sq->stats.syncp);

> @@ -1710,7 +1710,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)

>   	}

>   

>   	if (kick || netif_xmit_stopped(txq)) {

> -		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {

> +		if (virtqueue_kick_try(sq->vq)) {

>   			u64_stats_update_begin(&sq->stats.syncp);

>   			sq->stats.kicks++;

>   			u64_stats_update_end(&sq->stats.syncp);

> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c

> index 71e16b53e9c1..1462be756875 100644

> --- a/drivers/virtio/virtio_ring.c

> +++ b/drivers/virtio/virtio_ring.c

> @@ -1874,6 +1874,26 @@ bool virtqueue_kick(struct virtqueue *vq)

>   }

>   EXPORT_SYMBOL_GPL(virtqueue_kick);

>   

> +/**

> + * virtqueue_kick_try - try update after add_buf

> + * @vq: the struct virtqueue

> + *

> + * After one or more virtqueue_add_* calls, invoke this to kick

> + * the other side.

> + *

> + * Caller must ensure we don't call this with other virtqueue

> + * operations at the same time (except where noted).

> + *

> + * Returns true if kick success, otherwise false.

> + */

> +bool virtqueue_kick_try(struct virtqueue *vq)

> +{

> +	if (virtqueue_kick_prepare(vq) && virtqueue_notify(vq))

> +		return true;

> +	return false;

> +}

> +EXPORT_SYMBOL_GPL(virtqueue_kick_try);

> +

>   /**

>    * virtqueue_get_buf - get the next used buffer

>    * @_vq: the struct virtqueue we're talking about.

> diff --git a/include/linux/virtio.h b/include/linux/virtio.h

> index b1894e0323fa..45cd6a0af24d 100644

> --- a/include/linux/virtio.h

> +++ b/include/linux/virtio.h

> @@ -59,6 +59,8 @@ int virtqueue_add_sgs(struct virtqueue *vq,

>   

>   bool virtqueue_kick(struct virtqueue *vq);

>   

> +bool virtqueue_kick_try(struct virtqueue *vq);

> +

>   bool virtqueue_kick_prepare(struct virtqueue *vq);

>   

>   bool virtqueue_notify(struct virtqueue *vq);
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 9b6a4a875c55..167697030cb6 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -617,7 +617,7 @@  static int virtnet_xdp_xmit(struct net_device *dev,
 	ret = nxmit;
 
 	if (flags & XDP_XMIT_FLUSH) {
-		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
+		if (virtqueue_kick_try(sq->vq))
 			kicks = 1;
 	}
 out:
@@ -1325,7 +1325,7 @@  static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
 		if (err)
 			break;
 	} while (rq->vq->num_free);
-	if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {
+	if (virtqueue_kick_try(rq->vq)) {
 		unsigned long flags;
 
 		flags = u64_stats_update_begin_irqsave(&rq->stats.syncp);
@@ -1533,7 +1533,7 @@  static int virtnet_poll(struct napi_struct *napi, int budget)
 
 	if (xdp_xmit & VIRTIO_XDP_TX) {
 		sq = virtnet_xdp_get_sq(vi);
-		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
+		if (virtqueue_kick_try(sq->vq)) {
 			u64_stats_update_begin(&sq->stats.syncp);
 			sq->stats.kicks++;
 			u64_stats_update_end(&sq->stats.syncp);
@@ -1710,7 +1710,7 @@  static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 	}
 
 	if (kick || netif_xmit_stopped(txq)) {
-		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
+		if (virtqueue_kick_try(sq->vq)) {
 			u64_stats_update_begin(&sq->stats.syncp);
 			sq->stats.kicks++;
 			u64_stats_update_end(&sq->stats.syncp);
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 71e16b53e9c1..1462be756875 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1874,6 +1874,26 @@  bool virtqueue_kick(struct virtqueue *vq)
 }
 EXPORT_SYMBOL_GPL(virtqueue_kick);
 
+/**
+ * virtqueue_kick_try - try update after add_buf
+ * @vq: the struct virtqueue
+ *
+ * After one or more virtqueue_add_* calls, invoke this to kick
+ * the other side.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ *
+ * Returns true if kick success, otherwise false.
+ */
+bool virtqueue_kick_try(struct virtqueue *vq)
+{
+	if (virtqueue_kick_prepare(vq) && virtqueue_notify(vq))
+		return true;
+	return false;
+}
+EXPORT_SYMBOL_GPL(virtqueue_kick_try);
+
 /**
  * virtqueue_get_buf - get the next used buffer
  * @_vq: the struct virtqueue we're talking about.
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index b1894e0323fa..45cd6a0af24d 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -59,6 +59,8 @@  int virtqueue_add_sgs(struct virtqueue *vq,
 
 bool virtqueue_kick(struct virtqueue *vq);
 
+bool virtqueue_kick_try(struct virtqueue *vq);
+
 bool virtqueue_kick_prepare(struct virtqueue *vq);
 
 bool virtqueue_notify(struct virtqueue *vq);