1 files changed, 123 insertions, 0 deletions
diff --git a/net/ipv4/ipvs/ip_vs_lc.c b/net/ipv4/ipvs/ip_vs_lc.c
new file mode 100644
index 000000000000..d88fef90a641
--- /dev/null
+++ b/net/ipv4/ipvs/ip_vs_lc.c
@@ -0,0 +1,123 @@
+/*
+ * IPVS:        Least-Connection Scheduling module
+ *
+ * Version:     $Id: ip_vs_lc.c,v 1.10 2003/04/18 09:03:16 wensong Exp $
+ *
+ * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
+ *
+ *              This program is free software; you can redistribute it and/or
+ *              modify it under the terms of the GNU General Public License
+ *              as published by the Free Software Foundation; either version
+ *              2 of the License, or (at your option) any later version.
+ *
+ * Changes:
+ *     Wensong Zhang            :     added the ip_vs_lc_update_svc
+ *     Wensong Zhang            :     added any dest with weight=0 is quiesced
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include <net/ip_vs.h>
+
+
+static int ip_vs_lc_init_svc(struct ip_vs_service *svc)
+{
+	return 0;
+}
+
+
+static int ip_vs_lc_done_svc(struct ip_vs_service *svc)
+{
+	return 0;
+}
+
+
+static int ip_vs_lc_update_svc(struct ip_vs_service *svc)
+{
+	return 0;
+}
+
+
+static inline unsigned int
+ip_vs_lc_dest_overhead(struct ip_vs_dest *dest)
+{
+	/*
+	 * We think the overhead of processing active connections is 256
+	 * times higher than that of inactive connections in average. (This
+	 * 256 times might not be accurate, we will change it later) We
+	 * use the following formula to estimate the overhead now:
+	 *		  dest->activeconns*256 + dest->inactconns
+	 */
+	return (atomic_read(&dest->activeconns) << 8) +
+		atomic_read(&dest->inactconns);
+}
+
+
+/*
+ *	Least Connection scheduling
+ */
+static struct ip_vs_dest *
+ip_vs_lc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
+{
+	struct ip_vs_dest *dest, *least = NULL;
+	unsigned int loh = 0, doh;
+
+	IP_VS_DBG(6, "ip_vs_lc_schedule(): Scheduling...\n");
+
+	/*
+	 * Simply select the server with the least number of
+	 *        (activeconns<<5) + inactconns
+	 * Except whose weight is equal to zero.
+	 * If the weight is equal to zero, it means that the server is
+	 * quiesced, the existing connections to the server still get
+	 * served, but no new connection is assigned to the server.
+	 */
+
+	list_for_each_entry(dest, &svc->destinations, n_list) {
+		if ((dest->flags & IP_VS_DEST_F_OVERLOAD) ||
+		    atomic_read(&dest->weight) == 0)
+			continue;
+		doh = ip_vs_lc_dest_overhead(dest);
+		if (!least || doh < loh) {
+			least = dest;
+			loh = doh;
+		}
+	}
+
+	if (least)
+	IP_VS_DBG(6, "LC: server %u.%u.%u.%u:%u activeconns %d inactconns %d\n",
+		  NIPQUAD(least->addr), ntohs(least->port),
+		  atomic_read(&least->activeconns),
+		  atomic_read(&least->inactconns));
+
+	return least;
+}
+
+
+static struct ip_vs_scheduler ip_vs_lc_scheduler = {
+	.name =			"lc",
+	.refcnt =		ATOMIC_INIT(0),
+	.module =		THIS_MODULE,
+	.init_service =		ip_vs_lc_init_svc,
+	.done_service =		ip_vs_lc_done_svc,
+	.update_service =	ip_vs_lc_update_svc,
+	.schedule =		ip_vs_lc_schedule,
+};
+
+
+static int __init ip_vs_lc_init(void)
+{
+	INIT_LIST_HEAD(&ip_vs_lc_scheduler.n_list);
+	return register_ip_vs_scheduler(&ip_vs_lc_scheduler) ;
+}
+
+static void __exit ip_vs_lc_cleanup(void)
+{
+	unregister_ip_vs_scheduler(&ip_vs_lc_scheduler);
+}
+
+module_init(ip_vs_lc_init);
+module_exit(ip_vs_lc_cleanup);
+MODULE_LICENSE("GPL");