From: Eric Dumazet <edumazet@google.com>
Date: Mon, 30 Jun 2025 09:35:40 +0000 (+0000)
Subject: udp: move udp_memory_allocated into net_aligned_data
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e3d4825124bce0d1f72187fabcf972b7c0b6cb9b;p=thirdparty%2Flinux.git

udp: move udp_memory_allocated into net_aligned_data

____cacheline_aligned_in_smp attribute only makes sure to align
a field to a cache line. It does not prevent the linker to use
the remaining of the cache line for other variables, causing
potential false sharing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250630093540.3052835-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/include/net/aligned_data.h b/include/net/aligned_data.h
index bedb4f86b0fea..e1a1c8aedc797 100644
--- a/include/net/aligned_data.h
+++ b/include/net/aligned_data.h
@@ -13,6 +13,7 @@ struct net_aligned_data {
 	atomic64_t	net_cookie ____cacheline_aligned_in_smp;
 #if defined(CONFIG_INET)
 	atomic_long_t tcp_memory_allocated ____cacheline_aligned_in_smp;
+	atomic_long_t udp_memory_allocated ____cacheline_aligned_in_smp;
 #endif
 };
 
diff --git a/include/net/udp.h b/include/net/udp.h
index a772510b2aa58..f8ae2c4ade141 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -205,7 +205,6 @@ static inline void udp_hash4_dec(struct udp_hslot *hslot2)
 
 extern struct proto udp_prot;
 
-extern atomic_long_t udp_memory_allocated;
 DECLARE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
 
 /* sysctl variables for udp */
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 19573ee64a0f1..49f43c54cfb0e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -127,8 +127,6 @@ struct udp_table udp_table __read_mostly;
 long sysctl_udp_mem[3] __read_mostly;
 EXPORT_IPV6_MOD(sysctl_udp_mem);
 
-atomic_long_t udp_memory_allocated ____cacheline_aligned_in_smp;
-EXPORT_IPV6_MOD(udp_memory_allocated);
 DEFINE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
 EXPORT_PER_CPU_SYMBOL_GPL(udp_memory_per_cpu_fw_alloc);
 
@@ -3235,7 +3233,7 @@ struct proto udp_prot = {
 #ifdef CONFIG_BPF_SYSCALL
 	.psock_update_sk_prot	= udp_bpf_update_proto,
 #endif
-	.memory_allocated	= &udp_memory_allocated,
+	.memory_allocated	= &net_aligned_data.udp_memory_allocated,
 	.per_cpu_fw_alloc	= &udp_memory_per_cpu_fw_alloc,
 
 	.sysctl_mem		= sysctl_udp_mem,
diff --git a/net/ipv4/udp_impl.h b/net/ipv4/udp_impl.h
index e1ff3a3759961..c7142213fc211 100644
--- a/net/ipv4/udp_impl.h
+++ b/net/ipv4/udp_impl.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _UDP4_IMPL_H
 #define _UDP4_IMPL_H
+#include <net/aligned_data.h>
 #include <net/udp.h>
 #include <net/udplite.h>
 #include <net/protocol.h>
diff --git a/net/ipv4/udplite.c b/net/ipv4/udplite.c
index af37af3ab727b..d3e621a11a1aa 100644
--- a/net/ipv4/udplite.c
+++ b/net/ipv4/udplite.c
@@ -60,7 +60,7 @@ struct proto 	udplite_prot = {
 	.rehash		   = udp_v4_rehash,
 	.get_port	   = udp_v4_get_port,
 
-	.memory_allocated  = &udp_memory_allocated,
+	.memory_allocated  = &net_aligned_data.udp_memory_allocated,
 	.per_cpu_fw_alloc  = &udp_memory_per_cpu_fw_alloc,
 
 	.sysctl_mem	   = sysctl_udp_mem,
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index ebb95d8bc6819..6bbdadbd5fecc 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1925,7 +1925,7 @@ struct proto udpv6_prot = {
 	.psock_update_sk_prot	= udp_bpf_update_proto,
 #endif
 
-	.memory_allocated	= &udp_memory_allocated,
+	.memory_allocated	= &net_aligned_data.udp_memory_allocated,
 	.per_cpu_fw_alloc	= &udp_memory_per_cpu_fw_alloc,
 
 	.sysctl_mem		= sysctl_udp_mem,
diff --git a/net/ipv6/udp_impl.h b/net/ipv6/udp_impl.h
index 0590f566379d7..8a406be25a3a6 100644
--- a/net/ipv6/udp_impl.h
+++ b/net/ipv6/udp_impl.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _UDP6_IMPL_H
 #define _UDP6_IMPL_H
+#include <net/aligned_data.h>
 #include <net/udp.h>
 #include <net/udplite.h>
 #include <net/protocol.h>
diff --git a/net/ipv6/udplite.c b/net/ipv6/udplite.c
index a60bec9b14f14..2cec542437f74 100644
--- a/net/ipv6/udplite.c
+++ b/net/ipv6/udplite.c
@@ -59,7 +59,7 @@ struct proto udplitev6_prot = {
 	.rehash		   = udp_v6_rehash,
 	.get_port	   = udp_v6_get_port,
 
-	.memory_allocated  = &udp_memory_allocated,
+	.memory_allocated  = &net_aligned_data.udp_memory_allocated,
 	.per_cpu_fw_alloc  = &udp_memory_per_cpu_fw_alloc,
 
 	.sysctl_mem	   = sysctl_udp_mem,