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authorEric Dumazet <dada1@cosmosbay.com>2005-12-22 12:49:22 -0800
committerDavid S. Miller <davem@sunset.davemloft.net>2006-01-03 13:11:15 -0800
commit90ddc4f0470427df306f308ad03db6b6b21644b8 (patch)
treef97c1d57b25585394ebbd4b42b8d42a339f98644 /include/net
parent77d76ea310b50a9c8ff15bd290fcb4ed4961adf2 (diff)
[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 <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/inet_common.h4
-rw-r--r--include/net/ipv6.h4
-rw-r--r--include/net/protocol.h2
3 files changed, 5 insertions, 5 deletions
diff --git a/include/net/inet_common.h b/include/net/inet_common.h
index f943306ce5f..227adcbdfec 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 e3d5d7bc883..11a725662c3 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 a29cb29647d..63f7db99c2a 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