net: cache align tcp_memory_allocated, tcp_sockets_allocated

tcp_memory_allocated and tcp_sockets_allocated often share
a common cache line, source of false sharing.

Also take care of udp_memory_allocated and mptcp_sockets_allocated.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp.c

@@ -292,7 +292,7 @@ EXPORT_PER_CPU_SYMBOL_GPL(tcp_orphan_count);
 long sysctl_tcp_mem[3] __read_mostly;
 EXPORT_SYMBOL(sysctl_tcp_mem);
 
-atomic_long_t tcp_memory_allocated;	/* Current allocated memory. */
+atomic_long_t tcp_memory_allocated ____cacheline_aligned_in_smp;	/* Current allocated memory. */
 EXPORT_SYMBOL(tcp_memory_allocated);
 
 #if IS_ENABLED(CONFIG_SMC)
@@ -303,7 +303,7 @@ EXPORT_SYMBOL(tcp_have_smc);
 /*
  * Current number of TCP sockets.
  */
-struct percpu_counter tcp_sockets_allocated;
+struct percpu_counter tcp_sockets_allocated ____cacheline_aligned_in_smp;
 EXPORT_SYMBOL(tcp_sockets_allocated);
 
 /*

net/ipv4/udp.c

@@ -122,7 +122,7 @@ EXPORT_SYMBOL(udp_table);
 long sysctl_udp_mem[3] __read_mostly;
 EXPORT_SYMBOL(sysctl_udp_mem);
 
-atomic_long_t udp_memory_allocated;
+atomic_long_t udp_memory_allocated ____cacheline_aligned_in_smp;
 EXPORT_SYMBOL(udp_memory_allocated);
 
 #define MAX_UDP_PORTS 65536

net/mptcp/protocol.c

@@ -48,7 +48,7 @@ enum {
 	MPTCP_CMSG_TS = BIT(0),
 };
 
-static struct percpu_counter mptcp_sockets_allocated;
+static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp;
 
 static void __mptcp_destroy_sock(struct sock *sk);
 static void __mptcp_check_send_data_fin(struct sock *sk);