tipc: change socket buffer overflow control to respect sk_rcvbuf
As per feedback from the netdev community, we change the buffer
overflow protection algorithm in receiving sockets so that it
always respects the nominal upper limit set in sk_rcvbuf.
Instead of scaling up from a small sk_rcvbuf value, which leads to
violation of the configured sk_rcvbuf limit, we now calculate the
weighted per-message limit by scaling down from a much bigger value,
still in the same field, according to the importance priority of the
received message.
To allow for administrative tunability of the socket receive buffer
size, we create a tipc_rmem sysctl variable to allow the user to
configure an even bigger value via sysctl command. It is a size of
three (min/default/max) to be consistent with things like tcp_rmem.
By default, the value initialized in tipc_rmem[1] is equal to the
receive socket size needed by a TIPC_CRITICAL_IMPORTANCE message.
This value is also set as the default value of sk_rcvbuf.
Originally-by: Jon Maloy <jon.maloy@ericsson.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Jon Maloy <jon.maloy@ericsson.com>
[Ying: added sysctl variation to Jon's original patch]
Signed-off-by: Ying Xue <ying.xue@windriver.com>
[PG: don't compile sysctl.c if not config'd; add Documentation]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/core.c b/net/tipc/core.c
index 7ec2c1e..b0e42a0 100644
--- a/net/tipc/core.c
+++ b/net/tipc/core.c
@@ -39,6 +39,7 @@
#include "name_table.h"
#include "subscr.h"
#include "config.h"
+#include "port.h"
#include <linux/module.h>
@@ -50,7 +51,7 @@
int tipc_max_ports __read_mostly;
int tipc_net_id __read_mostly;
int tipc_remote_management __read_mostly;
-
+int sysctl_tipc_rmem[3] __read_mostly; /* min/default/max */
/**
* tipc_buf_acquire - creates a TIPC message buffer
@@ -118,6 +119,7 @@
tipc_nametbl_stop();
tipc_ref_table_stop();
tipc_socket_stop();
+ tipc_unregister_sysctl();
}
/**
@@ -142,13 +144,14 @@
res = tipc_netlink_start();
if (!res)
res = tipc_socket_init();
+ if (!res)
+ res = tipc_register_sysctl();
if (res)
tipc_core_stop();
return res;
}
-
static int __init tipc_init(void)
{
int res;
@@ -160,6 +163,11 @@
tipc_max_ports = CONFIG_TIPC_PORTS;
tipc_net_id = 4711;
+ sysctl_tipc_rmem[0] = CONN_OVERLOAD_LIMIT >> 4 << TIPC_LOW_IMPORTANCE;
+ sysctl_tipc_rmem[1] = CONN_OVERLOAD_LIMIT >> 4 <<
+ TIPC_CRITICAL_IMPORTANCE;
+ sysctl_tipc_rmem[2] = CONN_OVERLOAD_LIMIT;
+
res = tipc_core_start();
if (res)
pr_err("Unable to start in single node mode\n");
