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ipv4: use skb coalescing in defragmentation

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ip_frag_reasm() can use skb_try_coalesce() to build optimized skb,
reducing memory used by them (truesize), and reducing number of cache
line misses and overhead for the consumer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2012-05-19 03:02:20 +00:00 • committed by David S. Miller
commit 3cc4949269
1 changed files with 20 additions and 6 deletions
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26
net/ipv4/ip_fragment.c
View file

@ -545,6 +545,7 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
int len; int len;
int ihlen; int ihlen;
int err; int err;
int sum_truesize;
u8 ecn; u8 ecn;
ipq_kill(qp); ipq_kill(qp);
@ -611,19 +612,32 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
atomic_add(clone->truesize, &qp->q.net->mem); atomic_add(clone->truesize, &qp->q.net->mem);
} }
skb_shinfo(head)->frag_list = head->next;
skb_push(head, head->data - skb_network_header(head)); skb_push(head, head->data - skb_network_header(head));
for (fp=head->next; fp; fp = fp->next) { sum_truesize = head->truesize;
head->data_len += fp->len; for (fp = head->next; fp;) {
head->len += fp->len; bool headstolen;
int delta;
struct sk_buff *next = fp->next;
sum_truesize += fp->truesize;
if (head->ip_summed != fp->ip_summed) if (head->ip_summed != fp->ip_summed)
head->ip_summed = CHECKSUM_NONE; head->ip_summed = CHECKSUM_NONE;
else if (head->ip_summed == CHECKSUM_COMPLETE) else if (head->ip_summed == CHECKSUM_COMPLETE)
head->csum = csum_add(head->csum, fp->csum); head->csum = csum_add(head->csum, fp->csum);
head->truesize += fp->truesize;
if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
kfree_skb_partial(fp, headstolen);
} else {
if (!skb_shinfo(head)->frag_list)
skb_shinfo(head)->frag_list = fp;
head->data_len += fp->len;
head->len += fp->len;
head->truesize += fp->truesize;
}
fp = next;
} }
atomic_sub(head->truesize, &qp->q.net->mem); atomic_sub(sum_truesize, &qp->q.net->mem);
head->next = NULL; head->next = NULL;
head->dev = dev; head->dev = dev;