1 files changed, 36 insertions, 1 deletions

diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 0071ee6f441f..74fb2eb833ec 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -264,6 +264,22 @@ static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
         .fill_dst =             xfrm4_fill_dst,
 };
 
+#ifdef CONFIG_SYSCTL
+static struct ctl_table xfrm4_policy_table[] = {
+        {
+                .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "xfrm4_gc_thresh",
+                .data           = &xfrm4_dst_ops.gc_thresh,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec,
+        },
+        { }
+};
+
+static struct ctl_table_header *sysctl_hdr;
+#endif
+
 static void __init xfrm4_policy_init(void)
 {
         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
@@ -271,12 +287,31 @@ static void __init xfrm4_policy_init(void)
 
 static void __exit xfrm4_policy_fini(void)
 {
+#ifdef CONFIG_SYSCTL
+        if (sysctl_hdr)
+                unregister_net_sysctl_table(sysctl_hdr);
+#endif
         xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
 }
 
-void __init xfrm4_init(void)
+void __init xfrm4_init(int rt_max_size)
 {
         xfrm4_state_init();
         xfrm4_policy_init();
+        /*
+         * Select a default value for the gc_thresh based on the main route
+         * table hash size.  It seems to me the worst case scenario is when
+         * we have ipsec operating in transport mode, in which we create a
+         * dst_entry per socket.  The xfrm gc algorithm starts trying to remove
+         * entries at gc_thresh, and prevents new allocations as 2*gc_thresh
+         * so lets set an initial xfrm gc_thresh value at the rt_max_size/2.
+         * That will let us store an ipsec connection per route table entry,
+         * and start cleaning when were 1/2 full
+         */
+        xfrm4_dst_ops.gc_thresh = rt_max_size/2;
+#ifdef CONFIG_SYSCTL
+        sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv4_ctl_path,
+                                                xfrm4_policy_table);
+#endif
 }