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/linux/net.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/net.h') diff --git a/include/linux/net.h b/include/linux/net.h index d6a41e6577f6..28195a2d8ff0 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -107,7 +107,7 @@ enum sock_type { struct socket { socket_state state; unsigned long flags; - struct proto_ops *ops; + const struct proto_ops *ops; struct fasync_struct *fasync_list; struct file *file; struct sock *sk; @@ -260,7 +260,7 @@ SOCKCALL_WRAP(name, recvmsg, (struct kiocb *iocb, struct socket *sock, struct ms SOCKCALL_WRAP(name, mmap, (struct file *file, struct socket *sock, struct vm_area_struct *vma), \ (file, sock, vma)) \ \ -static struct proto_ops name##_ops = { \ +static const struct proto_ops name##_ops = { \ .family = fam, \ .owner = THIS_MODULE, \ .release = __lock_##name##_release, \ -- cgit v1.2.3-59-g8ed1b