Re: [RFC PATCH V2 5/5] Add TX zero copy in macvtap

From: Eric Dumazet
Date: Fri Dec 10 2010 - 05:27:55 EST


Le vendredi 10 dÃcembre 2010 Ã 02:13 -0800, Shirley Ma a Ãcrit :

> + while (len) {
> + f = &skb_shinfo(skb)->frags[i];
> + f->page = page[i];
> + f->page_offset = base & ~PAGE_MASK;
> + f->size = min_t(int, len, PAGE_SIZE - f->page_offset);
> + skb->data_len += f->size;
> + skb->len += f->size;
> + skb->truesize += f->size;
> + skb_shinfo(skb)->nr_frags++;
> + /* increase sk_wmem_alloc */
> + atomic_add(f->size, &skb->sk->sk_wmem_alloc);
> + base += f->size;
> + len -= f->size;
> + i++;
> + }

You could make one atomic_add() outside of the loop, and factorize many
things...

atomic_add(len, &skb->sk->sk_wmem_alloc);
skb->data_len += len;
skb->len += len;
skb->truesize += len;
while (len) {
...
}


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