Merge branch 'net-group-together-hot-data'

Eric Dumazet says:

====================
net: group together hot data

While our recent structure reorganizations were focused
on increasing max throughput, there is still an
area where improvements are much needed.

In many cases, a cpu handles one packet at a time,
instead of a nice batch.

Hardware interrupt.
 -> Software interrupt.
   -> Network/Protocol stacks.

If the cpu was idle or busy in other layers,
it has to pull many cache lines.

This series adds a new net_hotdata structure, where
some critical (and read-mostly) data used in
rx and tx path is packed in a small number of cache lines.

Synthetic benchmarks will not see much difference,
but latency of single packet should improve.

net_hodata current size on 64bit is 416 bytes,
but might grow in the future.

Also move RPS definitions to a new include file.
====================

Link: https://lore.kernel.org/r/20240306160031.874438-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/include/net/gro.h b/include/net/gro.h
index 2b58671a6549..d6fc8fbd3730 100644
--- a/include/net/gro.h
+++ b/include/net/gro.h
@@ -9,6 +9,7 @@
 #include <net/ip6_checksum.h>
 #include <linux/skbuff.h>
 #include <net/udp.h>
+#include <net/hotdata.h>
 
 struct napi_gro_cb {
 	union {
@@ -446,7 +447,7 @@ static inline void gro_normal_one(struct napi_struct *napi, struct sk_buff *skb,
 {
 	list_add_tail(&skb->list, &napi->rx_list);
 	napi->rx_count += segs;
-	if (napi->rx_count >= READ_ONCE(gro_normal_batch))
+	if (napi->rx_count >= READ_ONCE(net_hotdata.gro_normal_batch))
 		gro_normal_list(napi);
 }
 
@@ -493,6 +494,4 @@ static inline void inet6_get_iif_sdif(const struct sk_buff *skb, int *iif, int *
 #endif
 }
 
-extern struct list_head offload_base;
-
 #endif /* _NET_IPV6_GRO_H */