diff options
| author | Eric Dumazet <edumazet@google.com> | 2012-04-30 12:10:34 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-05-01 05:35:49 +0400 |
| commit | d7e8883cfcf4851afe74fb380cc62b7fa9cf66ba (patch) | |
| tree | 1b513349c4f1c7edf7991de2016b3a2ed1083deb /net/core/skbuff.c | |
| parent | 8d4057a938481351dc690fbe23e8c72af08d5890 (diff) | |
| download | linux-d7e8883cfcf4851afe74fb380cc62b7fa9cf66ba.tar.xz | |
net: make GRO aware of skb->head_frag
GRO can check if skb to be merged has its skb->head mapped to a page
fragment, instead of a kmalloc() area.
We 'upgrade' skb->head as a fragment in itself
This avoids the frag_list fallback, and permits to build true GRO skb
(one sk_buff and up to 16 fragments), using less memory.
This reduces number of cache misses when user makes its copy, since a
single sk_buff is fetched.
This is a followup of patch "net: allow skb->head to be a page fragment"
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Matt Carlson <mcarlson@broadcom.com>
Cc: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/skbuff.c')
| -rw-r--r-- | net/core/skbuff.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index effa75d0e318..09cc38651b2f 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -69,7 +69,7 @@ #include <trace/events/skb.h> #include <linux/highmem.h> -static struct kmem_cache *skbuff_head_cache __read_mostly; +struct kmem_cache *skbuff_head_cache __read_mostly; static struct kmem_cache *skbuff_fclone_cache __read_mostly; static void sock_pipe_buf_release(struct pipe_inode_info *pipe, @@ -2901,6 +2901,31 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) NAPI_GRO_CB(skb)->free = 1; goto done; + } else if (skb->head_frag) { + int nr_frags = pinfo->nr_frags; + skb_frag_t *frag = pinfo->frags + nr_frags; + struct page *page = virt_to_head_page(skb->head); + unsigned int first_size = headlen - offset; + unsigned int first_offset; + + if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) + return -E2BIG; + + first_offset = skb->data - + (unsigned char *)page_address(page) + + offset; + + pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; + + frag->page.p = page; + frag->page_offset = first_offset; + skb_frag_size_set(frag, first_size); + + memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); + /* We dont need to clear skbinfo->nr_frags here */ + + NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; + goto done; } else if (skb_gro_len(p) != pinfo->gso_size) return -E2BIG; |