diff mbox series

[net-next,v2,2/3] vsock/virtio: add SIOCOUTQ support for all virtio based transports

Message ID AS2P194MB2170FDCADD288267B874B6AC9A002@AS2P194MB2170.EURP194.PROD.OUTLOOK.COM (mailing list archive)
State New
Headers show
Series This patch series introduce the support for ioctl(s) in AF_VSOCK. | expand

Commit Message

Luigi Leonardi April 8, 2024, 1:37 p.m. UTC
This patch introduce support for stream_bytes_unsent and
seqpacket_bytes_unsent ioctl for virtio_transport, vhost_vsock
and vsock_loopback.

For all transports the unsent bytes counter is incremented
in virtio_transport_send_pkt_info.

In the virtio_transport (G2H) the counter is decremented each time the host
notifies the guest that it consumed the skbuffs.
In vhost-vsock (H2G) the counter is decremented after the skbuff is queued
in the virtqueue.
In vsock_loopback the counter is decremented after the skbuff is
dequeued.

Signed-off-by: Luigi Leonardi <luigi.leonardi@outlook.com>
---
 drivers/vhost/vsock.c                   |  4 ++-
 include/linux/virtio_vsock.h            |  7 ++++++
 net/vmw_vsock/virtio_transport.c        |  4 ++-
 net/vmw_vsock/virtio_transport_common.c | 33 +++++++++++++++++++++++++
 net/vmw_vsock/vsock_loopback.c          |  7 ++++++
 5 files changed, 53 insertions(+), 2 deletions(-)

Comments

Paolo Abeni April 11, 2024, 7:09 a.m. UTC | #1
On Mon, 2024-04-08 at 15:37 +0200, Luigi Leonardi wrote:
> This patch introduce support for stream_bytes_unsent and
> seqpacket_bytes_unsent ioctl for virtio_transport, vhost_vsock
> and vsock_loopback.
> 
> For all transports the unsent bytes counter is incremented
> in virtio_transport_send_pkt_info.
> 
> In the virtio_transport (G2H) the counter is decremented each time the host
> notifies the guest that it consumed the skbuffs.
> In vhost-vsock (H2G) the counter is decremented after the skbuff is queued
> in the virtqueue.
> In vsock_loopback the counter is decremented after the skbuff is
> dequeued.
> 
> Signed-off-by: Luigi Leonardi <luigi.leonardi@outlook.com>

I think this deserve an explicit ack from Stefano, and Stefano can't
review patches in the next few weeks. If it's not urgent this will have
to wait a bit.

> ---
>  drivers/vhost/vsock.c                   |  4 ++-
>  include/linux/virtio_vsock.h            |  7 ++++++
>  net/vmw_vsock/virtio_transport.c        |  4 ++-
>  net/vmw_vsock/virtio_transport_common.c | 33 +++++++++++++++++++++++++
>  net/vmw_vsock/vsock_loopback.c          |  7 ++++++
>  5 files changed, 53 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index ec20ecff85c7..dba8b3ea37bf 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -244,7 +244,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>  					restart_tx = true;
>  			}
>  
> -			consume_skb(skb);
> +			virtio_transport_consume_skb_sent(skb, true);
>  		}
>  	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
>  	if (added)
> @@ -451,6 +451,8 @@ static struct virtio_transport vhost_transport = {
>  		.notify_buffer_size       = virtio_transport_notify_buffer_size,
>  		.notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat,
>  
> +		.unsent_bytes             = virtio_transport_bytes_unsent,
> +
>  		.read_skb = virtio_transport_read_skb,
>  	},
>  
> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> index c82089dee0c8..dbb22d45d203 100644
> --- a/include/linux/virtio_vsock.h
> +++ b/include/linux/virtio_vsock.h
> @@ -134,6 +134,8 @@ struct virtio_vsock_sock {
>  	u32 peer_fwd_cnt;
>  	u32 peer_buf_alloc;
>  
> +	atomic_t bytes_unsent;

This will add 2 atomic operations per packet, possibly on contended
cachelines. Have you considered leveraging the existing transport-level
lock to protect the counter updates?


Thanks

Paolo
diff mbox series

Patch

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index ec20ecff85c7..dba8b3ea37bf 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -244,7 +244,7 @@  vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 					restart_tx = true;
 			}
 
-			consume_skb(skb);
+			virtio_transport_consume_skb_sent(skb, true);
 		}
 	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
 	if (added)
@@ -451,6 +451,8 @@  static struct virtio_transport vhost_transport = {
 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
 		.notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat,
 
+		.unsent_bytes             = virtio_transport_bytes_unsent,
+
 		.read_skb = virtio_transport_read_skb,
 	},
 
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index c82089dee0c8..dbb22d45d203 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -134,6 +134,8 @@  struct virtio_vsock_sock {
 	u32 peer_fwd_cnt;
 	u32 peer_buf_alloc;
 
+	atomic_t bytes_unsent;
+
 	/* Protected by rx_lock */
 	u32 fwd_cnt;
 	u32 last_fwd_cnt;
@@ -193,6 +195,11 @@  s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);
 s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
 u32 virtio_transport_seqpacket_has_data(struct vsock_sock *vsk);
 
+int virtio_transport_bytes_unsent(struct vsock_sock *vsk);
+
+void virtio_transport_consume_skb_sent(struct sk_buff *skb,
+				       bool consume);
+
 int virtio_transport_do_socket_init(struct vsock_sock *vsk,
 				 struct vsock_sock *psk);
 int
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index ee5d306a96d0..a4656d0a2567 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -311,7 +311,7 @@  static void virtio_transport_tx_work(struct work_struct *work)
 
 		virtqueue_disable_cb(vq);
 		while ((skb = virtqueue_get_buf(vq, &len)) != NULL) {
-			consume_skb(skb);
+			virtio_transport_consume_skb_sent(skb, true);
 			added = true;
 		}
 	} while (!virtqueue_enable_cb(vq));
@@ -540,6 +540,8 @@  static struct virtio_transport virtio_transport = {
 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
 		.notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat,
 
+		.unsent_bytes             = virtio_transport_bytes_unsent,
+
 		.read_skb = virtio_transport_read_skb,
 	},
 
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 16ff976a86e3..82a31a13dc32 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -419,6 +419,13 @@  static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
 		 */
 		rest_len -= ret;
 
+		/* Avoid to perform an atomic_add on 0 bytes.
+		 * This is equivalent to check on VIRTIO_VSOCK_OP_RW
+		 * as is the only packet type with payload.
+		 */
+		if (ret)
+			atomic_add(ret, &vvs->bytes_unsent);
+
 		if (WARN_ONCE(ret != skb_len,
 			      "'send_pkt()' returns %i, but %zu expected\n",
 			      ret, skb_len))
@@ -463,6 +470,23 @@  void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct sk_buff *
 }
 EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
 
+void virtio_transport_consume_skb_sent(struct sk_buff *skb, bool consume)
+{
+	struct sock *s = skb->sk;
+
+	if (s && skb->len) {
+		struct vsock_sock *vs = vsock_sk(s);
+		struct virtio_vsock_sock *vvs;
+
+		vvs = vs->trans;
+		atomic_sub(skb->len, &vvs->bytes_unsent);
+	}
+
+	if (consume)
+		consume_skb(skb);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_consume_skb_sent);
+
 u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
 {
 	u32 ret;
@@ -891,6 +915,7 @@  int virtio_transport_do_socket_init(struct vsock_sock *vsk,
 		vsk->buffer_size = VIRTIO_VSOCK_MAX_BUF_SIZE;
 
 	vvs->buf_alloc = vsk->buffer_size;
+	atomic_set(&vvs->bytes_unsent, 0);
 
 	spin_lock_init(&vvs->rx_lock);
 	spin_lock_init(&vvs->tx_lock);
@@ -1090,6 +1115,14 @@  void virtio_transport_destruct(struct vsock_sock *vsk)
 }
 EXPORT_SYMBOL_GPL(virtio_transport_destruct);
 
+int virtio_transport_bytes_unsent(struct vsock_sock *vsk)
+{
+	struct virtio_vsock_sock *vvs = vsk->trans;
+
+	return atomic_read(&vvs->bytes_unsent);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_bytes_unsent);
+
 static int virtio_transport_reset(struct vsock_sock *vsk,
 				  struct sk_buff *skb)
 {
diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index 6dea6119f5b2..9098613561e3 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -98,6 +98,8 @@  static struct virtio_transport loopback_transport = {
 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
 		.notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat,
 
+		.unsent_bytes             = virtio_transport_bytes_unsent,
+
 		.read_skb = virtio_transport_read_skb,
 	},
 
@@ -123,6 +125,11 @@  static void vsock_loopback_work(struct work_struct *work)
 	spin_unlock_bh(&vsock->pkt_queue.lock);
 
 	while ((skb = __skb_dequeue(&pkts))) {
+		/* Decrement the bytes_sent counter without deallocating skb
+		 * It is freed by the receiver.
+		 */
+		virtio_transport_consume_skb_sent(skb, false);
+
 		virtio_transport_deliver_tap_pkt(skb);
 		virtio_transport_recv_pkt(&loopback_transport, skb);
 	}