Commit 35bf8c86 authored Nov 25, 2021 by Jakub Kicinski

Merge branch 'net-small-csum-optimizations'

Eric Dumazet says:

====================
net: small csum optimizations

After recent x86 csum_partial() optimizations, we can more easily
see in kernel profiles costs of add/adc operations that could
be avoided, by feeding a non zero third argument to csum_partial()
====================

Link: https://lore.kernel.org/r/20211124202446.2917972-1-eric.dumazet@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parents 70331909 29c30026

include/linux/skbuff.h

+5 −1

Original line number	Diff line number	Diff line
		@@ -3485,7 +3485,11 @@ __skb_postpull_rcsum(struct sk_buff skb, const void start, unsigned int len,
		static inline void skb_postpull_rcsum(struct sk_buff *skb,
		const void *start, unsigned int len)
		{
		__skb_postpull_rcsum(skb, start, len, 0);
		if (skb->ip_summed == CHECKSUM_COMPLETE)
		skb->csum = ~csum_partial(start, len, ~skb->csum);
		else if (skb->ip_summed == CHECKSUM_PARTIAL &&
		skb_checksum_start_offset(skb) < 0)
		skb->ip_summed = CHECKSUM_NONE;
		}

		static __always_inline void

include/net/gro.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -173,8 +173,8 @@ static inline void skb_gro_postpull_rcsum(struct sk_buff *skb,
		const void *start, unsigned int len)
		{
		if (NAPI_GRO_CB(skb)->csum_valid)
		NAPI_GRO_CB(skb)->csum = csum_sub(NAPI_GRO_CB(skb)->csum,
		csum_partial(start, len, 0));
		NAPI_GRO_CB(skb)->csum = ~csum_partial(start, len,
		~NAPI_GRO_CB(skb)->csum);
		}

		/* GRO checksum functions. These are logical equivalents of the normal