From: Rusty Russell <rusty@rustcorp•com.au>
To: David Miller <davem@davemloft•net>
Cc: netdev@vger•kernel.org, markmc@redhat•com
Subject: Re: [PATCH 1/3] virtio_net: Recycle some more rx buffer pages
Date: Mon, 17 Nov 2008 17:35:43 +1030 [thread overview]
Message-ID: <200811171735.44025.rusty@rustcorp.com.au> (raw)
In-Reply-To: <20081116.194505.140648013.davem@davemloft.net>
On Monday 17 November 2008 14:15:05 David Miller wrote:
> From: Rusty Russell <rusty@rustcorp•com.au>
> Date: Mon, 17 Nov 2008 13:44:57 +1030
>
> > @@ -82,6 +82,16 @@ static void give_a_page(struct virtnet_info *vi,
> > struct page *page)
>
> -E_EMAIL_CLIENT_NEWLINES
From: Mark McLoughlin <markmc@redhat•com>
Each time we re-fill the recv queue with buffers, we allocate
one too many skbs and free it again when adding fails. We should
recycle the pages allocated in this case.
A previous version of this patch made trim_pages() trim trailing
unused pages from skbs with some paged data, but this actually
caused a barely measurable slowdown.
Signed-off-by: Mark McLoughlin <markmc@redhat•com>
Signed-off-by: Rusty Russell <rusty@rustcorp•com.au> (use netdev_priv)
---
drivers/net/virtio_net.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0196a0d..985271a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -82,6 +82,16 @@ static void give_a_page(struct virtnet_info *vi, struct page *page)
vi->pages = page;
}
+static void trim_pages(struct virtnet_info *vi, struct sk_buff *skb)
+{
+ unsigned int i;
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ give_a_page(vi, skb_shinfo(skb)->frags[i].page);
+ skb_shinfo(skb)->nr_frags = 0;
+ skb->data_len = 0;
+}
+
static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
{
struct page *p = vi->pages;
@@ -121,14 +131,8 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb,
}
len -= sizeof(struct virtio_net_hdr);
- if (len <= MAX_PACKET_LEN) {
- unsigned int i;
-
- for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
- give_a_page(dev->priv, skb_shinfo(skb)->frags[i].page);
- skb->data_len = 0;
- skb_shinfo(skb)->nr_frags = 0;
- }
+ if (len <= MAX_PACKET_LEN)
+ trim_pages(netdev_priv(dev), skb);
err = pskb_trim(skb, len);
if (err) {
@@ -232,6 +236,7 @@ static void try_fill_recv(struct virtnet_info *vi)
err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
if (err) {
skb_unlink(skb, &vi->recv);
+ trim_pages(vi, skb);
kfree_skb(skb);
break;
}
next prev parent reply other threads:[~2008-11-17 7:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-17 3:14 [PATCH 1/3] virtio_net: Recycle some more rx buffer pages Rusty Russell
2008-11-17 3:16 ` [PATCH 2/3] virtio_net: hook up the set-tso ethtool op Rusty Russell
2008-11-17 3:17 ` [PATCH 3/3] virtio_net: VIRTIO_NET_F_MSG_RXBUF (imprive rcv buffer allocation) Rusty Russell
2008-11-17 6:42 ` David Miller
2008-11-17 6:40 ` [PATCH 2/3] virtio_net: hook up the set-tso ethtool op David Miller
2008-11-17 3:45 ` [PATCH 1/3] virtio_net: Recycle some more rx buffer pages David Miller
2008-11-17 6:40 ` David Miller
2008-11-17 7:08 ` Rusty Russell
2008-11-17 7:14 ` David Miller
2008-11-17 7:05 ` Rusty Russell [this message]
2008-11-17 7:08 ` David Miller
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