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Commit 3cc49492 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv4: use skb coalescing in defragmentation 



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: default avatarEric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bad43ca8

net/ipv4/ip_fragment.c

+20 −6
Original line number Diff line number Diff line
@@ -545,6 +545,7 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 
	int len;

	int ihlen;

	int err;

	int sum_truesize;

	u8 ecn;



	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);

	}



	skb_shinfo(head)->frag_list = head->next;

	skb_push(head, head->data - skb_network_header(head));



	for (fp=head->next; fp; fp = fp->next) {

		head->data_len += fp->len;

		head->len += fp->len;

	sum_truesize = head->truesize;

	for (fp = head->next; fp;) {

		bool headstolen;

		int delta;

		struct sk_buff *next = fp->next;



		sum_truesize += fp->truesize;

		if (head->ip_summed != fp->ip_summed)

			head->ip_summed = CHECKSUM_NONE;

		else if (head->ip_summed == CHECKSUM_COMPLETE)

			head->csum = csum_add(head->csum, fp->csum);



		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;

		}

	atomic_sub(head->truesize, &qp->q.net->mem);

		fp = next;

	}

	atomic_sub(sum_truesize, &qp->q.net->mem);



	head->next = NULL;

	head->dev = dev;