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[NET]: move struct proto_ops to const

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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>
This commit is contained in:
Eric Dumazet
2005-12-22 12:49:22 -08:00
committed by David S. Miller
parent 77d76ea310
commit 90ddc4f047
33 changed files with 66 additions and 66 deletions
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16
net/irda/af_irda.c
View File

@@ -62,12 +62,12 @@
static int irda_create(struct socket *sock, int protocol);
static struct proto_ops irda_stream_ops;
static struct proto_ops irda_seqpacket_ops;
static struct proto_ops irda_dgram_ops;
static const struct proto_ops irda_stream_ops;
static const struct proto_ops irda_seqpacket_ops;
static const struct proto_ops irda_dgram_ops;
#ifdef CONFIG_IRDA_ULTRA
static struct proto_ops irda_ultra_ops;
static const struct proto_ops irda_ultra_ops;
#define ULTRA_MAX_DATA 382
#endif /* CONFIG_IRDA_ULTRA */
@@ -2464,7 +2464,7 @@ static struct net_proto_family irda_family_ops = {
.owner = THIS_MODULE,
};
static struct proto_ops SOCKOPS_WRAPPED(irda_stream_ops) = {
static const struct proto_ops SOCKOPS_WRAPPED(irda_stream_ops) = {
.family = PF_IRDA,
.owner = THIS_MODULE,
.release = irda_release,
@@ -2485,7 +2485,7 @@ static struct proto_ops SOCKOPS_WRAPPED(irda_stream_ops) = {
.sendpage = sock_no_sendpage,
};
static struct proto_ops SOCKOPS_WRAPPED(irda_seqpacket_ops) = {
static const struct proto_ops SOCKOPS_WRAPPED(irda_seqpacket_ops) = {
.family = PF_IRDA,
.owner = THIS_MODULE,
.release = irda_release,
@@ -2506,7 +2506,7 @@ static struct proto_ops SOCKOPS_WRAPPED(irda_seqpacket_ops) = {
.sendpage = sock_no_sendpage,
};
static struct proto_ops SOCKOPS_WRAPPED(irda_dgram_ops) = {
static const struct proto_ops SOCKOPS_WRAPPED(irda_dgram_ops) = {
.family = PF_IRDA,
.owner = THIS_MODULE,
.release = irda_release,
@@ -2528,7 +2528,7 @@ static struct proto_ops SOCKOPS_WRAPPED(irda_dgram_ops) = {
};
#ifdef CONFIG_IRDA_ULTRA
static struct proto_ops SOCKOPS_WRAPPED(irda_ultra_ops) = {
static const struct proto_ops SOCKOPS_WRAPPED(irda_ultra_ops) = {
.family = PF_IRDA,
.owner = THIS_MODULE,
.release = irda_release,