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-rw-r--r--net/ipv4/ipvs/ip_vs_wlc.c151
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
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+++ 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");
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