Merge branch 'inetpeer-reduce-false-sharing-and-atomic-operations'

Eric Dumazet says:

====================
inetpeer: reduce false sharing and atomic operations

After commit 8c2bd38b95f7 ("icmp: change the order of rate limits"),
there is a risk that a host receiving packets from an unique
source targeting closed ports is using a common inet_peer structure
from many cpus.

All these cpus have to acquire/release a refcount and update
the inet_peer timestamp (p->dtime)

Switch to pure RCU to avoid changing the refcount, and update
p->dtime only once per jiffy.

Tested:
  DUT : 128 cores, 32 hw rx queues.
  receiving 8,400,000 UDP packets per second, targeting closed ports.

Before the series:
- napi poll can not keep up, NIC drops 1,200,000 packets
  per second.
- We use 20 % of cpu cycles

After this series:
- All packets are received (no more hw drops)
- We use 12 % of cpu cycles.

v1: https://lore.kernel.org/20241213130212.1783302-1-edumazet@google.com
====================

Link: https://patch.msgid.link/20241215175629.1248773-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 5 insertions, 7 deletions

diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h
index 74ff688568a0..f475757daafb 100644
--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -96,30 +96,28 @@ static inline struct in6_addr *inetpeer_get_addr_v6(struct inetpeer_addr *iaddr)
 
 /* can be called with or without local BH being disabled */
 struct inet_peer *inet_getpeer(struct inet_peer_base *base,
-			       const struct inetpeer_addr *daddr,
-			       int create);
+			       const struct inetpeer_addr *daddr);
 
 static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
 						__be32 v4daddr,
-						int vif, int create)
+						int vif)
 {
 	struct inetpeer_addr daddr;
 
 	daddr.a4.addr = v4daddr;
 	daddr.a4.vif = vif;
 	daddr.family = AF_INET;
-	return inet_getpeer(base, &daddr, create);
+	return inet_getpeer(base, &daddr);
 }
 
 static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
-						const struct in6_addr *v6daddr,
-						int create)
+						const struct in6_addr *v6daddr)
 {
 	struct inetpeer_addr daddr;
 
 	daddr.a6 = *v6daddr;
 	daddr.family = AF_INET6;
-	return inet_getpeer(base, &daddr, create);
+	return inet_getpeer(base, &daddr);
 }
 
 static inline int inetpeer_addr_cmp(const struct inetpeer_addr *a,