net: minor optimization in __alloc_skb()

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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>

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Eric Dumazet 2022-07-07 19:18:46 +00:00 • committed by David S. Miller

parent 8e15145792

commit c2dd4059dc

1 changed files with 1 additions and 2 deletions

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net/core/skbuff.c

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