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Commit 55257d72 authored by Sasha Levin's avatar Sasha Levin Committed by Rusty Russell
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virtio-net: fill only rx queues which are being used 



Due to MQ support we may allocate a whole bunch of rx queues but
never use them. With this patch we'll safe the space used by
the receive buffers until they are actually in use:

sh-4.2# free -h
             total       used       free     shared    buffers     cached
Mem:          490M        35M       455M         0B         0B       4.1M
-/+ buffers/cache:        31M       459M
Swap:           0B         0B         0B
sh-4.2# ethtool -L eth0 combined 8
sh-4.2# free -h
             total       used       free     shared    buffers     cached
Mem:          490M       162M       327M         0B         0B       4.1M
-/+ buffers/cache:       158M       331M
Swap:           0B         0B         0B

Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 6b392717

drivers/net/virtio_net.c

+10 −5
Original line number Diff line number Diff line
@@ -581,7 +581,7 @@ static void refill_work(struct work_struct *work) 
	bool still_empty;

	int i;



	for (i = 0; i < vi->max_queue_pairs; i++) {

	for (i = 0; i < vi->curr_queue_pairs; i++) {

		struct receive_queue *rq = &vi->rq[i];



		napi_disable(&rq->napi);
@@ -636,7 +636,7 @@ static int virtnet_open(struct net_device *dev) 
	struct virtnet_info *vi = netdev_priv(dev);

	int i;



	for (i = 0; i < vi->max_queue_pairs; i++) {

	for (i = 0; i < vi->curr_queue_pairs; i++) {

		/* Make sure we have some buffers: if oom use wq. */

		if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))

			schedule_delayed_work(&vi->refill, 0);
@@ -900,6 +900,7 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs) 
	struct scatterlist sg;

	struct virtio_net_ctrl_mq s;

	struct net_device *dev = vi->dev;

	int i;



	if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))

		return 0;
@@ -912,8 +913,12 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs) 
		dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",

			 queue_pairs);

		return -EINVAL;

	} else

	} else {

		for (i = vi->curr_queue_pairs; i < queue_pairs; i++)

			if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))

				schedule_delayed_work(&vi->refill, 0);

		vi->curr_queue_pairs = queue_pairs;

	}



	return 0;

}
@@ -1566,7 +1571,7 @@ static int virtnet_probe(struct virtio_device *vdev) 
	}



	/* Last of all, set up some receive buffers. */

	for (i = 0; i < vi->max_queue_pairs; i++) {

	for (i = 0; i < vi->curr_queue_pairs; i++) {

		try_fill_recv(&vi->rq[i], GFP_KERNEL);



		/* If we didn't even get one input buffer, we're useless. */
@@ -1690,7 +1695,7 @@ static int virtnet_restore(struct virtio_device *vdev) 


	netif_device_attach(vi->dev);



	for (i = 0; i < vi->max_queue_pairs; i++)

	for (i = 0; i < vi->curr_queue_pairs; i++)

		if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))

			schedule_delayed_work(&vi->refill, 0);