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- /*
- * IPVS: Overflow-Connection Scheduling module
- *
- * Authors: Raducu Deaconu <rhadoo_io@yahoo.com>
- *
- * 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.
- *
- * Scheduler implements "overflow" loadbalancing according to number of active
- * connections , will keep all conections to the node with the highest weight
- * and overflow to the next node if the number of connections exceeds the node's
- * weight.
- * Note that this scheduler might not be suitable for UDP because it only uses
- * active connections
- *
- */
- #define KMSG_COMPONENT "IPVS"
- #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <net/ip_vs.h>
- /* OVF Connection scheduling */
- static struct ip_vs_dest *
- ip_vs_ovf_schedule(struct ip_vs_service *svc, const struct sk_buff *skb,
- struct ip_vs_iphdr *iph)
- {
- struct ip_vs_dest *dest, *h = NULL;
- int hw = 0, w;
- IP_VS_DBG(6, "ip_vs_ovf_schedule(): Scheduling...\n");
- /* select the node with highest weight, go to next in line if active
- * connections exceed weight
- */
- list_for_each_entry_rcu(dest, &svc->destinations, n_list) {
- w = atomic_read(&dest->weight);
- if ((dest->flags & IP_VS_DEST_F_OVERLOAD) ||
- atomic_read(&dest->activeconns) > w ||
- w == 0)
- continue;
- if (!h || w > hw) {
- h = dest;
- hw = w;
- }
- }
- if (h) {
- IP_VS_DBG_BUF(6, "OVF: server %s:%u active %d w %d\n",
- IP_VS_DBG_ADDR(h->af, &h->addr),
- ntohs(h->port),
- atomic_read(&h->activeconns),
- atomic_read(&h->weight));
- return h;
- }
- ip_vs_scheduler_err(svc, "no destination available");
- return NULL;
- }
- static struct ip_vs_scheduler ip_vs_ovf_scheduler = {
- .name = "ovf",
- .refcnt = ATOMIC_INIT(0),
- .module = THIS_MODULE,
- .n_list = LIST_HEAD_INIT(ip_vs_ovf_scheduler.n_list),
- .schedule = ip_vs_ovf_schedule,
- };
- static int __init ip_vs_ovf_init(void)
- {
- return register_ip_vs_scheduler(&ip_vs_ovf_scheduler);
- }
- static void __exit ip_vs_ovf_cleanup(void)
- {
- unregister_ip_vs_scheduler(&ip_vs_ovf_scheduler);
- synchronize_rcu();
- }
- module_init(ip_vs_ovf_init);
- module_exit(ip_vs_ovf_cleanup);
- MODULE_LICENSE("GPL");
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