NET : struct proto diet

Hi

After reading David's machines have NR_CPUS set to 4096, I realized how fat was 'struct proto', since it uses a stats[NR_CPUS] field to keep track of inuse sockets per protocol.

With NR_CPUS = 4096, this means we allocate 4096*SMP_CACHE_BYTES bytes per 'struct proto'.
As these structures are static (data section of kernel), this grows data kernel section by 256 KB per protocol.

This patch series does some cleanup and optimization.

[PATCH 1/4] NET : defines an infrastructure to keep 'inuse' changes in an efficent SMP/NUMA way.

[PATCH 2/4] NET : makes ipv4 use the  {DEFINE|REF}_PROTO_INUSE infrastructure
[PATCH 3/4] NET : makes ipv6 use the  {DEFINE|REF}_PROTO_INUSE infrastructure
[PATCH 4/4] NET : makes sctp use the  {DEFINE|REF}_PROTO_INUSE infrastructure

Thank you
Eric

From: Eric Dumazet <[email protected]>
Date: Mon, 05 Nov 2007 18:52:32 +0100

Applied, and because I love DCCP I added the following patch on top.

From: David S. Miller <[email protected]>
Date: Mon, 5 Nov 2007 23:42:25 -0800
Subject: [PATCH] [DCCP]: Use DEFINE_PROTO_INUSE infrastructure.

---
 net/dccp/ipv4.c |    3 +++
 net/dccp/ipv6.c |    3 +++
 2 files changed, 6 insertions(+), 0 deletions(-)

index 01a6a80..db17b83 100644
@@ -922,6 +922,8 @@ static struct timewait_sock_ops dccp_timewait_sock_ops = {
 	.twsk_obj_size	= sizeof(struct inet_timewait_sock),
 };
 
+DEFINE_PROTO_INUSE(dccp_v4)
+
 static struct proto dccp_v4_prot = {
 	.name			= "DCCP",
 	.owner			= THIS_MODULE,

@@ -950,6 +952,7 @@ static struct proto dccp_v4_prot = {
 	.compat_setsockopt	= compat_dccp_setsockopt,
 	.compat_getsockopt	= compat_dccp_getsockopt,
 #endif
+	REF_PROTO_INUSE(dccp_v4)
 };
 
 static struct net_protocol dccp_v4_protocol = {

index 62428ff..87c98fb 100644
@@ -1107,6 +1107,8 @@ static struct timewait_sock_ops dccp6_timewait_sock_ops = {
 	.twsk_obj_size	= sizeof(struct dccp6_timewait_sock),
 };
 
+DEFINE_PROTO_INUSE(dccp_v6)
+
 static struct proto dccp_v6_prot = {
 	.name		   = "DCCPv6",
 	.owner		   = THIS_MODULE,

@@ -1135,6 +1137,7 @@ static struct proto dccp_v6_prot = {
 	.compat_setsockopt = compat_dccp_setsockopt,
 	.compat_getsockopt = compat_dccp_getsockopt,
 #endif
+	REF_PROTO_INUSE(dccp_v6)
 };
 
 static struct inet6_protocol dccp_v6_protocol = {

1.5.3.5

Em Mon, Nov 05, 2007 at 11:43:06PM -0800, David Miller escreveu:

Thank you dudes. I found it so nice that I can't help but wonder if this wouldn't provide for an interesting "class", because this has nothing that is specific to network protocols, struct proto is just one user...

Lemme try to do this right now:

David,

Please consider pulling from:

master.kernel.org:/pub/scm/linux/kernel/git/acme/net-2.6

- Arnaldo