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gro: New frags interface to avoid copying shinfo

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It turns out that copying a 16-byte area at ~800k times a second
can be really expensive :) This patch redesigns the frags GRO
interface to avoid copying that area twice.

The two disciples of the frags interface have been converted.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu
2009-04-16 02:02:07 -07:00
committed by David S. Miller
parent 861ab44059
commit 76620aafd6
7 changed files with 102 additions and 94 deletions
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83
net/core/dev.c
View File

@@ -2519,16 +2519,10 @@ void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
}
EXPORT_SYMBOL(napi_reuse_skb);
struct sk_buff *napi_fraginfo_skb(struct napi_struct *napi,
struct napi_gro_fraginfo *info)
struct sk_buff *napi_get_frags(struct napi_struct *napi)
{
struct net_device *dev = napi->dev;
struct sk_buff *skb = napi->skb;
struct ethhdr *eth;
skb_frag_t *frag;
int i;
napi->skb = NULL;
if (!skb) {
skb = netdev_alloc_skb(dev, GRO_MAX_HEAD + NET_IP_ALIGN);
@@ -2536,47 +2530,14 @@ struct sk_buff *napi_fraginfo_skb(struct napi_struct *napi,
goto out;
skb_reserve(skb, NET_IP_ALIGN);
napi->skb = skb;
}
BUG_ON(info->nr_frags > MAX_SKB_FRAGS);
frag = &info->frags[info->nr_frags - 1];
for (i = skb_shinfo(skb)->nr_frags; i < info->nr_frags; i++) {
skb_fill_page_desc(skb, i, frag->page, frag->page_offset,
frag->size);
frag++;
}
skb_shinfo(skb)->nr_frags = info->nr_frags;
skb->data_len = info->len;
skb->len += info->len;
skb->truesize += info->len;
skb_reset_mac_header(skb);
skb_gro_reset_offset(skb);
eth = skb_gro_header(skb, sizeof(*eth));
if (!eth) {
napi_reuse_skb(napi, skb);
skb = NULL;
goto out;
}
skb_gro_pull(skb, sizeof(*eth));
/*
* This works because the only protocols we care about don't require
* special handling. We'll fix it up properly at the end.
*/
skb->protocol = eth->h_proto;
skb->ip_summed = info->ip_summed;
skb->csum = info->csum;
out:
return skb;
}
EXPORT_SYMBOL(napi_fraginfo_skb);
EXPORT_SYMBOL(napi_get_frags);
int napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb, int ret)
{
@@ -2606,9 +2567,39 @@ int napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb, int ret)
}
EXPORT_SYMBOL(napi_frags_finish);
int napi_gro_frags(struct napi_struct *napi, struct napi_gro_fraginfo *info)
struct sk_buff *napi_frags_skb(struct napi_struct *napi)
{
struct sk_buff *skb = napi_fraginfo_skb(napi, info);
struct sk_buff *skb = napi->skb;
struct ethhdr *eth;
napi->skb = NULL;
skb_reset_mac_header(skb);
skb_gro_reset_offset(skb);
eth = skb_gro_header(skb, sizeof(*eth));
if (!eth) {
napi_reuse_skb(napi, skb);
skb = NULL;
goto out;
}
skb_gro_pull(skb, sizeof(*eth));
/*
* This works because the only protocols we care about don't require
* special handling. We'll fix it up properly at the end.
*/
skb->protocol = eth->h_proto;
out:
return skb;
}
EXPORT_SYMBOL(napi_frags_skb);
int napi_gro_frags(struct napi_struct *napi)
{
struct sk_buff *skb = napi_frags_skb(napi);
if (!skb)
return NET_RX_DROP;
@@ -2712,7 +2703,7 @@ void netif_napi_del(struct napi_struct *napi)
struct sk_buff *skb, *next;
list_del_init(&napi->dev_list);
kfree_skb(napi->skb);
napi_free_frags(napi);
for (skb = napi->gro_list; skb; skb = next) {
next = skb->next;