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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 /net/llc
parent77d76ea310b50a9c8ff15bd290fcb4ed4961adf2 (diff)
downloadlinux-90ddc4f0470427df306f308ad03db6b6b21644b8.tar.gz
[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 'net/llc')
-rw-r--r--net/llc/af_llc.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index b6d3df5c911c..9cf65f9d8902 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -36,7 +36,7 @@
 static u16 llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
 static u16 llc_ui_sap_link_no_max[256];
 static struct sockaddr_llc llc_ui_addrnull;
-static struct proto_ops llc_ui_ops;
+static const struct proto_ops llc_ui_ops;
 
 static int llc_ui_wait_for_conn(struct sock *sk, long timeout);
 static int llc_ui_wait_for_disc(struct sock *sk, long timeout);
@@ -1098,7 +1098,7 @@ static struct net_proto_family llc_ui_family_ops = {
 	.owner	= THIS_MODULE,
 };
 
-static struct proto_ops llc_ui_ops = {
+static const struct proto_ops llc_ui_ops = {
 	.family	     = PF_LLC,
 	.owner       = THIS_MODULE,
 	.release     = llc_ui_release,