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Commit 5377d758 authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
Browse files

virtio_net: use DECLARE_EWMA 



Instead of using the out-of-line EWMA calculation, use DECLARE_EWMA()
to create static inlines. On x86/64 this results in no change in code
size for me, but reduces the struct receive_queue size by the two
unsigned long values that store the parameters.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0f8f27de

drivers/net/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -282,7 +282,6 @@ config VETH 
config VIRTIO_NET

	tristate "Virtio network driver"

	depends on VIRTIO

	select AVERAGE

	---help---

	  This is the virtual network driver for virtio.  It can be used with

	  lguest or QEMU based VMMs (like KVM or Xen).  Say Y or M.

drivers/net/virtio_net.c

+11 −11
Original line number Diff line number Diff line
@@ -40,12 +40,12 @@ module_param(gso, bool, 0444); 
#define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)

#define GOOD_COPY_LEN	128



/* Weight used for the RX packet size EWMA. The average packet size is used to

 * determine the packet buffer size when refilling RX rings. As the entire RX

 * ring may be refilled at once, the weight is chosen so that the EWMA will be

 * insensitive to short-term, transient changes in packet size.

/* RX packet size EWMA. The average packet size is used to determine the packet

 * buffer size when refilling RX rings. As the entire RX ring may be refilled

 * at once, the weight is chosen so that the EWMA will be insensitive to short-

 * term, transient changes in packet size.

 */

#define RECEIVE_AVG_WEIGHT 64

DECLARE_EWMA(pkt_len, 1, 64)



/* Minimum alignment for mergeable packet buffers. */

#define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, 256)
@@ -85,7 +85,7 @@ struct receive_queue { 
	struct page *pages;



	/* Average packet length for mergeable receive buffers. */

	struct ewma mrg_avg_pkt_len;

	struct ewma_pkt_len mrg_avg_pkt_len;



	/* Page frag for packet buffer allocation. */

	struct page_frag alloc_frag;
@@ -407,7 +407,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
		}

	}



	ewma_add(&rq->mrg_avg_pkt_len, head_skb->len);

	ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);

	return head_skb;



err_skb:
@@ -600,12 +600,12 @@ static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq, 
	return err;

}



static unsigned int get_mergeable_buf_len(struct ewma *avg_pkt_len)

static unsigned int get_mergeable_buf_len(struct ewma_pkt_len *avg_pkt_len)

{

	const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);

	unsigned int len;



	len = hdr_len + clamp_t(unsigned int, ewma_read(avg_pkt_len),

	len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len),

			GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);

	return ALIGN(len, MERGEABLE_BUFFER_ALIGN);

}
@@ -1615,7 +1615,7 @@ static int virtnet_alloc_queues(struct virtnet_info *vi) 
		napi_hash_add(&vi->rq[i].napi);



		sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));

		ewma_init(&vi->rq[i].mrg_avg_pkt_len, 1, RECEIVE_AVG_WEIGHT);

		ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);

		sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));

	}
@@ -1658,7 +1658,7 @@ static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue, 
{

	struct virtnet_info *vi = netdev_priv(queue->dev);

	unsigned int queue_index = get_netdev_rx_queue_index(queue);

	struct ewma *avg;

	struct ewma_pkt_len *avg;



	BUG_ON(queue_index >= vi->max_queue_pairs);

	avg = &vi->rq[queue_index].mrg_avg_pkt_len;