diff options
| author | Eric Dumazet <edumazet@google.com> | 2012-04-22 12:26:16 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-04-23 23:01:35 -0400 |
| commit | 41c73a0d44c902e92397552acce181295eaa448b (patch) | |
| tree | 522ac16cf3c1db59ef21e30cf14177dea1a7ea24 | |
| parent | 1402d366019fedaa2b024f2bac06b7cc9a8782e1 (diff) | |
net: speedup skb_splice_bits()
Commit 35f3d14db (pipe: add support for shrinking and growing pipes)
added a slowdown for splice(socket -> pipe), as we might grow the spd
used in skb_splice_bits() for each skb we process in splice() syscall.
Its not needed since skb lengths are capped. The default on-stack arrays
are more than enough.
Use MAX_SKB_FRAGS instead of PIPE_DEF_BUFFERS to describe the reasonable
limit per skb.
Add coalescing support to help splicing of GRO skbs built from linear
skbs (linked into frag_list)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/skbuff.c | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index bf257de95d2..dfb304066f2 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1581,11 +1581,20 @@ new_page: memcpy(page_address(p) + off, page_address(page) + *offset, *len); sk->sk_sndmsg_off += *len; *offset = off; - get_page(p); return p; } +static bool spd_can_coalesce(const struct splice_pipe_desc *spd, + struct page *page, + unsigned int offset) +{ + return spd->nr_pages && + spd->pages[spd->nr_pages - 1] == page && + (spd->partial[spd->nr_pages - 1].offset + + spd->partial[spd->nr_pages - 1].len == offset); +} + /* * Fill page/offset/length into spd, if it can hold more pages. */ @@ -1595,16 +1604,19 @@ static inline int spd_fill_page(struct splice_pipe_desc *spd, struct sk_buff *skb, int linear, struct sock *sk) { - if (unlikely(spd->nr_pages == pipe->buffers)) + if (unlikely(spd->nr_pages == MAX_SKB_FRAGS)) return 1; if (linear) { page = linear_to_page(page, len, &offset, skb, sk); if (!page) return 1; - } else - get_page(page); - + } + if (spd_can_coalesce(spd, page, offset)) { + spd->partial[spd->nr_pages - 1].len += *len; + return 0; + } + get_page(page); spd->pages[spd->nr_pages] = page; spd->partial[spd->nr_pages].len = *len; spd->partial[spd->nr_pages].offset = offset; @@ -1710,8 +1722,8 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset, struct pipe_inode_info *pipe, unsigned int tlen, unsigned int flags) { - struct partial_page partial[PIPE_DEF_BUFFERS]; - struct page *pages[PIPE_DEF_BUFFERS]; + struct partial_page partial[MAX_SKB_FRAGS]; + struct page *pages[MAX_SKB_FRAGS]; struct splice_pipe_desc spd = { .pages = pages, .partial = partial, @@ -1723,9 +1735,6 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset, struct sock *sk = skb->sk; int ret = 0; - if (splice_grow_spd(pipe, &spd)) - return -ENOMEM; - /* * __skb_splice_bits() only fails if the output has no room left, * so no point in going over the frag_list for the error case. @@ -1761,7 +1770,6 @@ done: lock_sock(sk); } - splice_shrink_spd(pipe, &spd); return ret; } |