From f450d539c05a14c103dd174718f81bb2fe65cb4b Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Sat, 13 Feb 2021 14:12:25 +0000 Subject: skbuff: introduce {,__}napi_build_skb() which reuses NAPI cache heads Instead of just bulk-flushing skbuff_heads queued up through napi_consume_skb() or __kfree_skb_defer(), try to reuse them on allocation path. If the cache is empty on allocation, bulk-allocate the first 16 elements, which is more efficient than per-skb allocation. If the cache is full on freeing, bulk-wipe the second half of the cache (32 elements). This also includes custom KASAN poisoning/unpoisoning to be double sure there are no use-after-free cases. To not change current behaviour, introduce a new function, napi_build_skb(), to optionally use a new approach later in drivers. Note on selected bulk size, 16: - this equals to XDP_BULK_QUEUE_SIZE, DEV_MAP_BULK_SIZE and especially VETH_XDP_BATCH, which is also used to bulk-allocate skbuff_heads and was tested on powerful setups; - this also showed the best performance in the actual test series (from the array of {8, 16, 32}). Suggested-by: Edward Cree # Divide on two halves Suggested-by: Eric Dumazet # KASAN poisoning Cc: Dmitry Vyukov # Help with KASAN Cc: Paolo Abeni # Reduced batch size Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller --- include/linux/skbuff.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 0e0707296098..906122eac82a 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1087,6 +1087,8 @@ struct sk_buff *build_skb(void *data, unsigned int frag_size); struct sk_buff *build_skb_around(struct sk_buff *skb, void *data, unsigned int frag_size); +struct sk_buff *napi_build_skb(void *data, unsigned int frag_size); + /** * alloc_skb - allocate a network buffer * @size: size to allocate -- cgit v1.2.3