diff options
| author | Eric Dumazet <edumazet@google.com> | 2022-07-07 19:18:46 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-07-08 14:21:08 +0100 |
| commit | c2dd4059dc31ee6f5b83c8d2064bb1f1f465bcec (patch) | |
| tree | ca262868da3fc1e3880a78ec3efc9beaa7522810 | |
| parent | 8e1514579246ddc36ba0b860fc8bdd03be085aee (diff) | |
net: minor optimization in __alloc_skb()
TCP allocates 'fast clones' skbs for packets in tx queues.
Currently, __alloc_skb() initializes the companion fclone
field to SKB_FCLONE_CLONE, and leaves other fields untouched.
It makes sense to defer this init much later in skb_clone(),
because all fclone fields are copied and hot in cpu caches
at that time.
This removes one cache line miss in __alloc_skb(), cost seen
on an host with 256 cpus all competing on memory accesses.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/skbuff.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index c62e42d0c531..c4a751781581 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -454,8 +454,6 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, skb->fclone = SKB_FCLONE_ORIG; refcount_set(&fclones->fclone_ref, 1); - - fclones->skb2.fclone = SKB_FCLONE_CLONE; } return skb; @@ -1513,6 +1511,7 @@ struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) refcount_read(&fclones->fclone_ref) == 1) { n = &fclones->skb2; refcount_set(&fclones->fclone_ref, 2); + n->fclone = SKB_FCLONE_CLONE; } else { if (skb_pfmemalloc(skb)) gfp_mask |= __GFP_MEMALLOC; |