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authorEric Dumazet <edumazet@google.com>2012-05-17 07:34:16 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-17 15:52:40 -0400
commita1c7fff7e18f59e684e07b0f9a770561cd39f395 (patch)
tree99b006ffc7423205ded8616a21eb955f1fe046dd /net
parent1de5a71c3e6eae2fbf15e9a9e13a8fc269bb82bc (diff)
downloadlinux-a1c7fff7e18f59e684e07b0f9a770561cd39f395.tar.gz
net: netdev_alloc_skb() use build_skb()
netdev_alloc_skb() is used by networks driver in their RX path to allocate an skb to receive an incoming frame. With recent skb->head_frag infrastructure, it makes sense to change netdev_alloc_skb() to use build_skb() and a frag allocator. This permits a zero copy splice(socket->pipe), and better GRO or TCP coalescing. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/skbuff.c32
1 files changed, 31 insertions, 1 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 7a10f089415..7645df1bada 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -293,6 +293,12 @@ struct sk_buff *build_skb(void *data, unsigned int frag_size)
}
EXPORT_SYMBOL(build_skb);
+struct netdev_alloc_cache {
+ struct page *page;
+ unsigned int offset;
+};
+static DEFINE_PER_CPU(struct netdev_alloc_cache, netdev_alloc_cache);
+
/**
* __netdev_alloc_skb - allocate an skbuff for rx on a specific device
* @dev: network device to receive on
@@ -310,8 +316,32 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
unsigned int length, gfp_t gfp_mask)
{
struct sk_buff *skb;
+ unsigned int fragsz = SKB_DATA_ALIGN(length + NET_SKB_PAD) +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
- skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, NUMA_NO_NODE);
+ if (fragsz <= PAGE_SIZE && !(gfp_mask & __GFP_WAIT)) {
+ struct netdev_alloc_cache *nc;
+ void *data = NULL;
+
+ nc = &get_cpu_var(netdev_alloc_cache);
+ if (!nc->page) {
+refill: nc->page = alloc_page(gfp_mask);
+ nc->offset = 0;
+ }
+ if (likely(nc->page)) {
+ if (nc->offset + fragsz > PAGE_SIZE) {
+ put_page(nc->page);
+ goto refill;
+ }
+ data = page_address(nc->page) + nc->offset;
+ nc->offset += fragsz;
+ get_page(nc->page);
+ }
+ put_cpu_var(netdev_alloc_cache);
+ skb = data ? build_skb(data, fragsz) : NULL;
+ } else {
+ skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, NUMA_NO_NODE);
+ }
if (likely(skb)) {
skb_reserve(skb, NET_SKB_PAD);
skb->dev = dev;