1 files changed, 151 insertions, 0 deletions

diff --git a/net/ipv4/ipvs/ip_vs_wlc.c b/net/ipv4/ipvs/ip_vs_wlc.c
new file mode 100644
index 000000000000..8a9d913261d8
--- /dev/null
+++ b/net/ipv4/ipvs/ip_vs_wlc.c
@@ -0,0 +1,151 @@
+/*
+ * IPVS:        Weighted Least-Connection Scheduling module
+ *
+ * Version:     $Id: ip_vs_wlc.c,v 1.13 2003/04/18 09:03:16 wensong Exp $
+ *
+ * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
+ *              Peter Kese <peter.kese@ijs.si>
+ *
+ *              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            :     changed the ip_vs_wlc_schedule to return dest
+ *     Wensong Zhang            :     changed to use the inactconns in scheduling
+ *     Wensong Zhang            :     changed some comestics things for debugging
+ *     Wensong Zhang            :     changed for the d-linked destination list
+ *     Wensong Zhang            :     added the ip_vs_wlc_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_wlc_init_svc(struct ip_vs_service *svc)
+{
+        return 0;
+}
+
+
+static int
+ip_vs_wlc_done_svc(struct ip_vs_service *svc)
+{
+        return 0;
+}
+
+
+static int
+ip_vs_wlc_update_svc(struct ip_vs_service *svc)
+{
+        return 0;
+}
+
+
+static inline unsigned int
+ip_vs_wlc_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);
+}
+
+
+/*
+ *      Weighted Least Connection scheduling
+ */
+static struct ip_vs_dest *
+ip_vs_wlc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
+{
+        struct ip_vs_dest *dest, *least;
+        unsigned int loh, doh;
+
+        IP_VS_DBG(6, "ip_vs_wlc_schedule(): Scheduling...\n");
+
+        /*
+         * We calculate the load of each dest server as follows:
+         *                (dest overhead) / dest->weight
+         *
+         * Remember -- no floats in kernel mode!!!
+         * The comparison of h1*w2 > h2*w1 is equivalent to that of
+         *                h1/w1 > h2/w2
+         * if every weight is larger than zero.
+         *
+         * The server with weight=0 is quiesced and will not receive any
+         * new connections.
+         */
+
+        list_for_each_entry(dest, &svc->destinations, n_list) {
+                if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) &&
+                    atomic_read(&dest->weight) > 0) {
+                        least = dest;
+                        loh = ip_vs_wlc_dest_overhead(least);
+                        goto nextstage;
+                }
+        }
+        return NULL;
+
+        /*
+         *    Find the destination with the least load.
+         */
+  nextstage:
+        list_for_each_entry_continue(dest, &svc->destinations, n_list) {
+                if (dest->flags & IP_VS_DEST_F_OVERLOAD)
+                        continue;
+                doh = ip_vs_wlc_dest_overhead(dest);
+                if (loh * atomic_read(&dest->weight) >
+                    doh * atomic_read(&least->weight)) {
+                        least = dest;
+                        loh = doh;
+                }
+        }
+
+        IP_VS_DBG(6, "WLC: server %u.%u.%u.%u:%u "
+                  "activeconns %d refcnt %d weight %d overhead %d\n",
+                  NIPQUAD(least->addr), ntohs(least->port),
+                  atomic_read(&least->activeconns),
+                  atomic_read(&least->refcnt),
+                  atomic_read(&least->weight), loh);
+
+        return least;
+}
+
+
+static struct ip_vs_scheduler ip_vs_wlc_scheduler =
+{
+        .name =                 "wlc",
+        .refcnt =               ATOMIC_INIT(0),
+        .module =               THIS_MODULE,
+        .init_service =         ip_vs_wlc_init_svc,
+        .done_service =         ip_vs_wlc_done_svc,
+        .update_service =       ip_vs_wlc_update_svc,
+        .schedule =             ip_vs_wlc_schedule,
+};
+
+
+static int __init ip_vs_wlc_init(void)
+{
+        INIT_LIST_HEAD(&ip_vs_wlc_scheduler.n_list);
+        return register_ip_vs_scheduler(&ip_vs_wlc_scheduler);
+}
+
+static void __exit ip_vs_wlc_cleanup(void)
+{
+        unregister_ip_vs_scheduler(&ip_vs_wlc_scheduler);
+}
+
+module_init(ip_vs_wlc_init);
+module_exit(ip_vs_wlc_cleanup);
+MODULE_LICENSE("GPL");