Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/net/ipv4/ipvs/ip_vs_wrr.c b/net/ipv4/ipvs/ip_vs_wrr.c
new file mode 100644
index 0000000..749fa04
--- /dev/null
+++ b/net/ipv4/ipvs/ip_vs_wrr.c
@@ -0,0 +1,235 @@
+/*
+ * IPVS: Weighted Round-Robin Scheduling module
+ *
+ * Version: $Id: ip_vs_wrr.c,v 1.12 2002/09/15 08:14:08 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 : changed the ip_vs_wrr_schedule to return dest
+ * Wensong Zhang : changed some comestics things for debugging
+ * Wensong Zhang : changed for the d-linked destination list
+ * Wensong Zhang : added the ip_vs_wrr_update_svc
+ * Julian Anastasov : fixed the bug of returning destination
+ * with weight 0 when all weights are zero
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include <net/ip_vs.h>
+
+/*
+ * current destination pointer for weighted round-robin scheduling
+ */
+struct ip_vs_wrr_mark {
+ struct list_head *cl; /* current list head */
+ int cw; /* current weight */
+ int mw; /* maximum weight */
+ int di; /* decreasing interval */
+};
+
+
+/*
+ * Get the gcd of server weights
+ */
+static int gcd(int a, int b)
+{
+ int c;
+
+ while ((c = a % b)) {
+ a = b;
+ b = c;
+ }
+ return b;
+}
+
+static int ip_vs_wrr_gcd_weight(struct ip_vs_service *svc)
+{
+ struct ip_vs_dest *dest;
+ int weight;
+ int g = 0;
+
+ list_for_each_entry(dest, &svc->destinations, n_list) {
+ weight = atomic_read(&dest->weight);
+ if (weight > 0) {
+ if (g > 0)
+ g = gcd(weight, g);
+ else
+ g = weight;
+ }
+ }
+ return g ? g : 1;
+}
+
+
+/*
+ * Get the maximum weight of the service destinations.
+ */
+static int ip_vs_wrr_max_weight(struct ip_vs_service *svc)
+{
+ struct ip_vs_dest *dest;
+ int weight = 0;
+
+ list_for_each_entry(dest, &svc->destinations, n_list) {
+ if (atomic_read(&dest->weight) > weight)
+ weight = atomic_read(&dest->weight);
+ }
+
+ return weight;
+}
+
+
+static int ip_vs_wrr_init_svc(struct ip_vs_service *svc)
+{
+ struct ip_vs_wrr_mark *mark;
+
+ /*
+ * Allocate the mark variable for WRR scheduling
+ */
+ mark = kmalloc(sizeof(struct ip_vs_wrr_mark), GFP_ATOMIC);
+ if (mark == NULL) {
+ IP_VS_ERR("ip_vs_wrr_init_svc(): no memory\n");
+ return -ENOMEM;
+ }
+ mark->cl = &svc->destinations;
+ mark->cw = 0;
+ mark->mw = ip_vs_wrr_max_weight(svc);
+ mark->di = ip_vs_wrr_gcd_weight(svc);
+ svc->sched_data = mark;
+
+ return 0;
+}
+
+
+static int ip_vs_wrr_done_svc(struct ip_vs_service *svc)
+{
+ /*
+ * Release the mark variable
+ */
+ kfree(svc->sched_data);
+
+ return 0;
+}
+
+
+static int ip_vs_wrr_update_svc(struct ip_vs_service *svc)
+{
+ struct ip_vs_wrr_mark *mark = svc->sched_data;
+
+ mark->cl = &svc->destinations;
+ mark->mw = ip_vs_wrr_max_weight(svc);
+ mark->di = ip_vs_wrr_gcd_weight(svc);
+ if (mark->cw > mark->mw)
+ mark->cw = 0;
+ return 0;
+}
+
+
+/*
+ * Weighted Round-Robin Scheduling
+ */
+static struct ip_vs_dest *
+ip_vs_wrr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
+{
+ struct ip_vs_dest *dest;
+ struct ip_vs_wrr_mark *mark = svc->sched_data;
+ struct list_head *p;
+
+ IP_VS_DBG(6, "ip_vs_wrr_schedule(): Scheduling...\n");
+
+ /*
+ * This loop will always terminate, because mark->cw in (0, max_weight]
+ * and at least one server has its weight equal to max_weight.
+ */
+ write_lock(&svc->sched_lock);
+ p = mark->cl;
+ while (1) {
+ if (mark->cl == &svc->destinations) {
+ /* it is at the head of the destination list */
+
+ if (mark->cl == mark->cl->next) {
+ /* no dest entry */
+ dest = NULL;
+ goto out;
+ }
+
+ mark->cl = svc->destinations.next;
+ mark->cw -= mark->di;
+ if (mark->cw <= 0) {
+ mark->cw = mark->mw;
+ /*
+ * Still zero, which means no available servers.
+ */
+ if (mark->cw == 0) {
+ mark->cl = &svc->destinations;
+ IP_VS_INFO("ip_vs_wrr_schedule(): "
+ "no available servers\n");
+ dest = NULL;
+ goto out;
+ }
+ }
+ } else
+ mark->cl = mark->cl->next;
+
+ if (mark->cl != &svc->destinations) {
+ /* not at the head of the list */
+ dest = list_entry(mark->cl, struct ip_vs_dest, n_list);
+ if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) &&
+ atomic_read(&dest->weight) >= mark->cw) {
+ /* got it */
+ break;
+ }
+ }
+
+ if (mark->cl == p && mark->cw == mark->di) {
+ /* back to the start, and no dest is found.
+ It is only possible when all dests are OVERLOADED */
+ dest = NULL;
+ goto out;
+ }
+ }
+
+ IP_VS_DBG(6, "WRR: server %u.%u.%u.%u:%u "
+ "activeconns %d refcnt %d weight %d\n",
+ NIPQUAD(dest->addr), ntohs(dest->port),
+ atomic_read(&dest->activeconns),
+ atomic_read(&dest->refcnt),
+ atomic_read(&dest->weight));
+
+ out:
+ write_unlock(&svc->sched_lock);
+ return dest;
+}
+
+
+static struct ip_vs_scheduler ip_vs_wrr_scheduler = {
+ .name = "wrr",
+ .refcnt = ATOMIC_INIT(0),
+ .module = THIS_MODULE,
+ .init_service = ip_vs_wrr_init_svc,
+ .done_service = ip_vs_wrr_done_svc,
+ .update_service = ip_vs_wrr_update_svc,
+ .schedule = ip_vs_wrr_schedule,
+};
+
+static int __init ip_vs_wrr_init(void)
+{
+ INIT_LIST_HEAD(&ip_vs_wrr_scheduler.n_list);
+ return register_ip_vs_scheduler(&ip_vs_wrr_scheduler) ;
+}
+
+static void __exit ip_vs_wrr_cleanup(void)
+{
+ unregister_ip_vs_scheduler(&ip_vs_wrr_scheduler);
+}
+
+module_init(ip_vs_wrr_init);
+module_exit(ip_vs_wrr_cleanup);
+MODULE_LICENSE("GPL");