Message ID | 1500276760.5566.5.camel@edumazet-glaptop3.roam.corp.google.com |
---|---|
State | RFC, archived |
Delegated to: | David Miller |
Headers | show |
2017-07-17 15:32 GMT+08:00 Eric Dumazet <eric.dumazet@gmail.com>: > On Mon, 2017-07-17 at 10:22 +0800, Lin Zhang wrote: >> In the pull_pages code block, if the first frag size > eat, >> we can end the loop in advance to avoid extra copy. >> >> Signed-off-by: Lin Zhang <xiaolou4617@gmail.com> >> --- >> net/core/skbuff.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/net/core/skbuff.c b/net/core/skbuff.c >> index f990eb8..c00a1df 100644 >> --- a/net/core/skbuff.c >> +++ b/net/core/skbuff.c >> @@ -1720,6 +1720,10 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta) >> skb_shinfo(skb)->frags[k].page_offset += eat; >> skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat); >> eat = 0; >> + if (!i) { >> + k = skb_shinfo(skb)->nr_frags; >> + break; >> + } >> } >> k++; >> } > > -CC lkml (no need to spam lkml for netdev patches ) > > Why even reading skb_shinfo(skb)->nr_frags to write it again ? > > I would use something like : > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 8b11341ed69ad97d34dd3e9b73c8c44ef7c452ff..a562b0e61afa3faf7abdd7f9209ae9096310fb7d 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -1719,13 +1719,15 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta) > if (eat) { > skb_shinfo(skb)->frags[k].page_offset += eat; > skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat); > + if (!i) > + goto end; > eat = 0; > } > k++; > } > } > skb_shinfo(skb)->nr_frags = k; > - > +end: > skb->tail += delta; > skb->data_len -= delta; > > > > > Yes, this change it is looks like better than me. :)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 8b11341ed69ad97d34dd3e9b73c8c44ef7c452ff..a562b0e61afa3faf7abdd7f9209ae9096310fb7d 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1719,13 +1719,15 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta) if (eat) { skb_shinfo(skb)->frags[k].page_offset += eat; skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat); + if (!i) + goto end; eat = 0; } k++; } } skb_shinfo(skb)->nr_frags = k; - +end: skb->tail += delta; skb->data_len -= delta;