Subject: [PATCH 5/5] udp: add udp_rmem_min and udp_wmem_min

From: Hideo AOKI <[email-masked]>
Date: Thu, 15 Nov 2007 16:50:23 -0500

This patch added /proc/sys/net/ipv4/udp_rmem_min and
/proc/sys/net/ipv4/udp_rmem_min. Each UDP packet is drooped when the
number of pages for socket buffer is beyond the limit and the socket
already consumes minimum buffer.

Cc: Satoshi Oshima <[email-masked]>
signed-off-by: Hideo Aoki <[email-masked]>
---

 Documentation/networking/ip-sysctl.txt |   12 ++++++++++++
 include/net/udp.h                      |    4 ++++
 net/ipv4/ip_output.c                   |    4 +++-
 net/ipv4/sysctl_net_ipv4.c             |   20 ++++++++++++++++++++
 net/ipv4/udp.c                         |   13 +++++++++++--
 5 files changed, 50 insertions(+), 3 deletions(-)

diff -pruN net-2.6-udp-p4/Documentation/networking/ip-sysctl.txt net-2.6-udp-p5/Documentation/networking/ip-sysctl.txt
--- net-2.6-udp-p4/Documentation/networking/ip-sysctl.txt	2007-11-15 14:44:21.000000000 -0500
+++ net-2.6-udp-p5/Documentation/networking/ip-sysctl.txt	2007-11-15 14:44:23.000000000 -0500
@@ -452,6 +452,18 @@ udp_mem - INTEGER
 	Number of pages allowed for queueing by all UDP sockets.
 	Default is calculated at boot time from amount of available memory.

+udp_rmem_min - INTEGER
+	Minimal size of receive buffer used by UDP sockets. Each UDP socket
+	is able to use the size for receiving data, even if total pages of UDP
+	sockets exceed udp_mem. The unit is byte.
+	Default: 4096
+
+udp_wmem_min - INTEGER
+	Minimal size of send buffer used by UDP sockets. Each UDP socket is
+	able to use the size for sending data, even if total pages of UDP
+	sockets exceed udp_mem. The unit is byte.
+	Default: 4096
+
 CIPSOv4 Variables:

 cipso_cache_enable - BOOLEAN
diff -pruN net-2.6-udp-p4/include/net/udp.h net-2.6-udp-p5/include/net/udp.h
--- net-2.6-udp-p4/include/net/udp.h	2007-11-15 14:44:21.000000000 -0500
+++ net-2.6-udp-p5/include/net/udp.h	2007-11-15 14:44:23.000000000 -0500
@@ -66,7 +66,11 @@ extern rwlock_t udp_hash_lock;
 extern struct proto udp_prot;

 extern atomic_t udp_memory_allocated;
+
+/* sysctl variables for udp */
 extern int sysctl_udp_mem;
+extern int sysctl_udp_rmem_min;
+extern int sysctl_udp_wmem_min;

 struct sk_buff;

diff -pruN net-2.6-udp-p4/net/ipv4/ip_output.c net-2.6-udp-p5/net/ipv4/ip_output.c
--- net-2.6-udp-p4/net/ipv4/ip_output.c	2007-11-15 14:44:21.000000000 -0500
+++ net-2.6-udp-p5/net/ipv4/ip_output.c	2007-11-15 14:44:23.000000000 -0500
@@ -705,7 +705,9 @@ static inline int __ip_check_max_skb_pag
 	switch(sk->sk_protocol) {
 	case IPPROTO_UDP:
 		if (atomic_read(sk->sk_prot->memory_allocated) + size
-		    > sk->sk_prot->sysctl_mem[0])
+		    > sk->sk_prot->sysctl_mem[0] &&
+		    atomic_read(&sk->sk_wmem_alloc) + size
+		    > sk->sk_prot->sysctl_wmem[0])
 			return -ENOBUFS;
 		/* Fall through */	
 	default:
diff -pruN net-2.6-udp-p4/net/ipv4/sysctl_net_ipv4.c net-2.6-udp-p5/net/ipv4/sysctl_net_ipv4.c
--- net-2.6-udp-p4/net/ipv4/sysctl_net_ipv4.c	2007-11-15 14:44:21.000000000 -0500
+++ net-2.6-udp-p5/net/ipv4/sysctl_net_ipv4.c	2007-11-15 14:44:23.000000000 -0500
@@ -896,6 +896,26 @@ ctl_table ipv4_table[] = {
 		.strategy	= &sysctl_intvec,
 		.extra1		= &zero
 	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "udp_rmem_min",
+		.data		= &sysctl_udp_rmem_min,
+		.maxlen		= sizeof(sysctl_udp_rmem_min),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &zero
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "udp_wmem_min",
+		.data		= &sysctl_udp_wmem_min,
+		.maxlen		= sizeof(sysctl_udp_wmem_min),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &zero
+	},
 	{ .ctl_name = 0 }
 };

diff -pruN net-2.6-udp-p4/net/ipv4/udp.c net-2.6-udp-p5/net/ipv4/udp.c
--- net-2.6-udp-p4/net/ipv4/udp.c	2007-11-15 14:44:21.000000000 -0500
+++ net-2.6-udp-p5/net/ipv4/udp.c	2007-11-15 14:44:23.000000000 -0500
@@ -117,6 +117,8 @@ DEFINE_RWLOCK(udp_hash_lock);

 atomic_t udp_memory_allocated;
 int sysctl_udp_mem __read_mostly;
+int sysctl_udp_rmem_min __read_mostly;
+int sysctl_udp_wmem_min __read_mostly;

 static inline int __udp_lib_lport_inuse(__u16 num,
 					const struct hlist_head udptable[])
@@ -1027,8 +1029,10 @@ int udp_queue_rcv_skb(struct sock * sk,
 	}

 	if ((atomic_read(sk->sk_prot->memory_allocated)
-		       + sk_datagram_pages(skb->truesize))
-		> sk->sk_prot->sysctl_mem[0]) {
+	     + sk_datagram_pages(skb->truesize))
+	    > sk->sk_prot->sysctl_mem[0] &&
+	    atomic_read(&sk->sk_rmem_alloc) + skb->truesize
+	    > sk->sk_prot->sysctl_rmem[0]) {
 		UDP_INC_STATS_BH(UDP_MIB_RCVBUFERRORS, up->pcflag);
 		goto drop;
 	}
@@ -1471,6 +1475,8 @@ struct proto udp_prot = {
 	.get_port	   = udp_v4_get_port,
 	.memory_allocated  = &udp_memory_allocated,
 	.sysctl_mem	   = &sysctl_udp_mem,
+	.sysctl_wmem	   = &sysctl_udp_wmem_min,
+	.sysctl_rmem	   = &sysctl_udp_rmem_min,
 	.obj_size	   = sizeof(struct udp_sock),
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_udp_setsockopt,
@@ -1678,6 +1684,9 @@ void __init udp_init(void)
 	limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
 	limit = max(limit, 128UL);
 	sysctl_udp_mem = limit / 2 * 3;
+
+	sysctl_udp_rmem_min = SK_DATAGRAM_MEM_QUANTUM;
+	sysctl_udp_wmem_min = SK_DATAGRAM_MEM_QUANTUM;
 }

 EXPORT_SYMBOL(udp_disconnect);
-- 
Hitachi Computer Products (America) Inc.