From 90ddc4f0470427df306f308ad03db6b6b21644b8 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 22 Dec 2005 12:49:22 -0800 Subject: [NET]: move struct proto_ops to const I noticed that some of 'struct proto_ops' used in the kernel may share a cache line used by locks or other heavily modified data. (default linker alignement is 32 bytes, and L1_CACHE_LINE is 64 or 128 at least) This patch makes sure a 'struct proto_ops' can be declared as const, so that all cpus can share all parts of it without false sharing. This is not mandatory : a driver can still use a read/write structure if it needs to (and eventually a __read_mostly) I made a global stubstitute to change all existing occurences to make them const. This should reduce the possibility of false sharing on SMP, and speedup some socket system calls. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/inet_common.h | 4 ++-- include/net/ipv6.h | 4 ++-- include/net/protocol.h | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) (limited to 'include/net') diff --git a/include/net/inet_common.h b/include/net/inet_common.h index f943306ce5ff..227adcbdfec8 100644 --- a/include/net/inet_common.h +++ b/include/net/inet_common.h @@ -1,8 +1,8 @@ #ifndef _INET_COMMON_H #define _INET_COMMON_H -extern struct proto_ops inet_stream_ops; -extern struct proto_ops inet_dgram_ops; +extern const struct proto_ops inet_stream_ops; +extern const struct proto_ops inet_dgram_ops; /* * INET4 prototypes used by INET6 diff --git a/include/net/ipv6.h b/include/net/ipv6.h index e3d5d7bc8837..11a725662c36 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -538,8 +538,8 @@ extern int sysctl_ip6frag_low_thresh; extern int sysctl_ip6frag_time; extern int sysctl_ip6frag_secret_interval; -extern struct proto_ops inet6_stream_ops; -extern struct proto_ops inet6_dgram_ops; +extern const struct proto_ops inet6_stream_ops; +extern const struct proto_ops inet6_dgram_ops; extern int ip6_mc_source(int add, int omode, struct sock *sk, struct group_source_req *pgsr); diff --git a/include/net/protocol.h b/include/net/protocol.h index a29cb29647d0..63f7db99c2a6 100644 --- a/include/net/protocol.h +++ b/include/net/protocol.h @@ -65,7 +65,7 @@ struct inet_protosw { int protocol; /* This is the L4 protocol number. */ struct proto *prot; - struct proto_ops *ops; + const struct proto_ops *ops; int capability; /* Which (if any) capability do * we need to use this socket -- cgit v1.2.3