diff mbox series

[v3,1/5] virtio_net: Revert "virtio_net: set the default max ring size by find_vqs()"

Message ID 20220815215938.154999-2-mst@redhat.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series virtio: drop sizing vqs during init | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Michael S. Tsirkin Aug. 15, 2022, 10 p.m. UTC 
This reverts commit 762faee5a2678559d3dc09d95f8f2c54cd0466a7.

This has been reported to trip up guests on GCP (Google Cloud).
The reason is that virtio_find_vqs_ctx_size is broken on legacy
devices. We can in theory fix virtio_find_vqs_ctx_size but
in fact the patch itself has several other issues:

- It treats unknown speed as < 10G
- It leaves userspace no way to find out the ring size set by hypervisor
- It tests speed when link is down
- It ignores the virtio spec advice:
        Both \field{speed} and \field{duplex} can change, thus the driver
        is expected to re-read these values after receiving a
        configuration change notification.
- It is not clear the performance impact has been tested properly

Revert the patch for now.

Reported-by: Andres Freund <andres@anarazel.de>
Link: https://lore.kernel.org/r/20220814212610.GA3690074%40roeck-us.net
Link: https://lore.kernel.org/r/20220815070203.plwjx7b3cyugpdt7%40awork3.anarazel.de
Link: https://lore.kernel.org/r/3df6bb82-1951-455d-a768-e9e1513eb667%40www.fastmail.com
Link: https://lore.kernel.org/r/FCDC5DDE-3CDD-4B8A-916F-CA7D87B547CE%40anarazel.de
Fixes: 762faee5a267 ("virtio_net: set the default max ring size by find_vqs()")
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Andres Freund <andres@anarazel.de>
Tested-by: From: Guenter Roeck <linux@roeck-us.net>
---
 drivers/net/virtio_net.c | 42 ++++------------------------------------
 1 file changed, 4 insertions(+), 38 deletions(-)

Comments

Guenter Roeck Aug. 15, 2022, 11:36 p.m. UTC | #1 
On Mon, Aug 15, 2022 at 06:00:25PM -0400, Michael S. Tsirkin wrote:
> This reverts commit 762faee5a2678559d3dc09d95f8f2c54cd0466a7.
> 
> This has been reported to trip up guests on GCP (Google Cloud).
> The reason is that virtio_find_vqs_ctx_size is broken on legacy
> devices. We can in theory fix virtio_find_vqs_ctx_size but
> in fact the patch itself has several other issues:
> 
> - It treats unknown speed as < 10G
> - It leaves userspace no way to find out the ring size set by hypervisor
> - It tests speed when link is down
> - It ignores the virtio spec advice:
>         Both \field{speed} and \field{duplex} can change, thus the driver
>         is expected to re-read these values after receiving a
>         configuration change notification.
> - It is not clear the performance impact has been tested properly
> 
> Revert the patch for now.
> 
> Reported-by: Andres Freund <andres@anarazel.de>
> Link: https://lore.kernel.org/r/20220814212610.GA3690074%40roeck-us.net
> Link: https://lore.kernel.org/r/20220815070203.plwjx7b3cyugpdt7%40awork3.anarazel.de
> Link: https://lore.kernel.org/r/3df6bb82-1951-455d-a768-e9e1513eb667%40www.fastmail.com
> Link: https://lore.kernel.org/r/FCDC5DDE-3CDD-4B8A-916F-CA7D87B547CE%40anarazel.de
> Fixes: 762faee5a267 ("virtio_net: set the default max ring size by find_vqs()")
> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> Tested-by: Andres Freund <andres@anarazel.de>
> Tested-by: From: Guenter Roeck <linux@roeck-us.net>

s/From: //

> ---
>  drivers/net/virtio_net.c | 42 ++++------------------------------------
>  1 file changed, 4 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index d934774e9733..ece00b84e3a7 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3432,29 +3432,6 @@ static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct virtqu
>  		   (unsigned int)GOOD_PACKET_LEN);
>  }
>  
> -static void virtnet_config_sizes(struct virtnet_info *vi, u32 *sizes)
> -{
> -	u32 i, rx_size, tx_size;
> -
> -	if (vi->speed == SPEED_UNKNOWN || vi->speed < SPEED_10000) {
> -		rx_size = 1024;
> -		tx_size = 1024;
> -
> -	} else if (vi->speed < SPEED_40000) {
> -		rx_size = 1024 * 4;
> -		tx_size = 1024 * 4;
> -
> -	} else {
> -		rx_size = 1024 * 8;
> -		tx_size = 1024 * 8;
> -	}
> -
> -	for (i = 0; i < vi->max_queue_pairs; i++) {
> -		sizes[rxq2vq(i)] = rx_size;
> -		sizes[txq2vq(i)] = tx_size;
> -	}
> -}
> -
>  static int virtnet_find_vqs(struct virtnet_info *vi)
>  {
>  	vq_callback_t **callbacks;
> @@ -3462,7 +3439,6 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
>  	int ret = -ENOMEM;
>  	int i, total_vqs;
>  	const char **names;
> -	u32 *sizes;
>  	bool *ctx;
>  
>  	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
> @@ -3490,15 +3466,10 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
>  		ctx = NULL;
>  	}
>  
> -	sizes = kmalloc_array(total_vqs, sizeof(*sizes), GFP_KERNEL);
> -	if (!sizes)
> -		goto err_sizes;
> -
>  	/* Parameters for control virtqueue, if any */
>  	if (vi->has_cvq) {
>  		callbacks[total_vqs - 1] = NULL;
>  		names[total_vqs - 1] = "control";
> -		sizes[total_vqs - 1] = 64;
>  	}
>  
>  	/* Allocate/initialize parameters for send/receive virtqueues */
> @@ -3513,10 +3484,8 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
>  			ctx[rxq2vq(i)] = true;
>  	}
>  
> -	virtnet_config_sizes(vi, sizes);
> -
> -	ret = virtio_find_vqs_ctx_size(vi->vdev, total_vqs, vqs, callbacks,
> -				       names, sizes, ctx, NULL);
> +	ret = virtio_find_vqs_ctx(vi->vdev, total_vqs, vqs, callbacks,
> +				  names, ctx, NULL);
>  	if (ret)
>  		goto err_find;
>  
> @@ -3536,8 +3505,6 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
>  
>  
>  err_find:
> -	kfree(sizes);
> -err_sizes:
>  	kfree(ctx);
>  err_ctx:
>  	kfree(names);
> @@ -3897,9 +3864,6 @@ static int virtnet_probe(struct virtio_device *vdev)
>  		vi->curr_queue_pairs = num_online_cpus();
>  	vi->max_queue_pairs = max_queue_pairs;
>  
> -	virtnet_init_settings(dev);
> -	virtnet_update_settings(vi);
> -
>  	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
>  	err = init_vqs(vi);
>  	if (err)
> @@ -3912,6 +3876,8 @@ static int virtnet_probe(struct virtio_device *vdev)
>  	netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
>  	netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
>  
> +	virtnet_init_settings(dev);
> +
>  	if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY)) {
>  		vi->failover = net_failover_create(vi->dev);
>  		if (IS_ERR(vi->failover)) {
> -- 
> MST
>
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d934774e9733..ece00b84e3a7 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3432,29 +3432,6 @@  static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct virtqu
 		   (unsigned int)GOOD_PACKET_LEN);
 }
 
-static void virtnet_config_sizes(struct virtnet_info *vi, u32 *sizes)
-{
-	u32 i, rx_size, tx_size;
-
-	if (vi->speed == SPEED_UNKNOWN || vi->speed < SPEED_10000) {
-		rx_size = 1024;
-		tx_size = 1024;
-
-	} else if (vi->speed < SPEED_40000) {
-		rx_size = 1024 * 4;
-		tx_size = 1024 * 4;
-
-	} else {
-		rx_size = 1024 * 8;
-		tx_size = 1024 * 8;
-	}
-
-	for (i = 0; i < vi->max_queue_pairs; i++) {
-		sizes[rxq2vq(i)] = rx_size;
-		sizes[txq2vq(i)] = tx_size;
-	}
-}
-
 static int virtnet_find_vqs(struct virtnet_info *vi)
 {
 	vq_callback_t **callbacks;
@@ -3462,7 +3439,6 @@  static int virtnet_find_vqs(struct virtnet_info *vi)
 	int ret = -ENOMEM;
 	int i, total_vqs;
 	const char **names;
-	u32 *sizes;
 	bool *ctx;
 
 	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
@@ -3490,15 +3466,10 @@  static int virtnet_find_vqs(struct virtnet_info *vi)
 		ctx = NULL;
 	}
 
-	sizes = kmalloc_array(total_vqs, sizeof(*sizes), GFP_KERNEL);
-	if (!sizes)
-		goto err_sizes;
-
 	/* Parameters for control virtqueue, if any */
 	if (vi->has_cvq) {
 		callbacks[total_vqs - 1] = NULL;
 		names[total_vqs - 1] = "control";
-		sizes[total_vqs - 1] = 64;
 	}
 
 	/* Allocate/initialize parameters for send/receive virtqueues */
@@ -3513,10 +3484,8 @@  static int virtnet_find_vqs(struct virtnet_info *vi)
 			ctx[rxq2vq(i)] = true;
 	}
 
-	virtnet_config_sizes(vi, sizes);
-
-	ret = virtio_find_vqs_ctx_size(vi->vdev, total_vqs, vqs, callbacks,
-				       names, sizes, ctx, NULL);
+	ret = virtio_find_vqs_ctx(vi->vdev, total_vqs, vqs, callbacks,
+				  names, ctx, NULL);
 	if (ret)
 		goto err_find;
 
@@ -3536,8 +3505,6 @@  static int virtnet_find_vqs(struct virtnet_info *vi)
 
 
 err_find:
-	kfree(sizes);
-err_sizes:
 	kfree(ctx);
 err_ctx:
 	kfree(names);
@@ -3897,9 +3864,6 @@  static int virtnet_probe(struct virtio_device *vdev)
 		vi->curr_queue_pairs = num_online_cpus();
 	vi->max_queue_pairs = max_queue_pairs;
 
-	virtnet_init_settings(dev);
-	virtnet_update_settings(vi);
-
 	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
 	err = init_vqs(vi);
 	if (err)
@@ -3912,6 +3876,8 @@  static int virtnet_probe(struct virtio_device *vdev)
 	netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
 	netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
 
+	virtnet_init_settings(dev);
+
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY)) {
 		vi->failover = net_failover_create(vi->dev);
 		if (IS_ERR(vi->failover)) {