| /* |
| * IPVS: Round-Robin Scheduling module |
| * |
| * 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. |
| * |
| * Fixes/Changes: |
| * Wensong Zhang : changed the ip_vs_rr_schedule to return dest |
| * Julian Anastasov : fixed the NULL pointer access bug in debugging |
| * Wensong Zhang : changed some comestics things for debugging |
| * Wensong Zhang : changed for the d-linked destination list |
| * Wensong Zhang : added the ip_vs_rr_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_rr_init_svc(struct ip_vs_service *svc) |
| { |
| svc->sched_data = &svc->destinations; |
| return 0; |
| } |
| |
| |
| static int ip_vs_rr_update_svc(struct ip_vs_service *svc) |
| { |
| svc->sched_data = &svc->destinations; |
| return 0; |
| } |
| |
| |
| /* |
| * Round-Robin Scheduling |
| */ |
| static struct ip_vs_dest * |
| ip_vs_rr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb) |
| { |
| struct list_head *p, *q; |
| struct ip_vs_dest *dest; |
| |
| IP_VS_DBG(6, "ip_vs_rr_schedule(): Scheduling...\n"); |
| |
| write_lock(&svc->sched_lock); |
| p = (struct list_head *)svc->sched_data; |
| p = p->next; |
| q = p; |
| do { |
| /* skip list head */ |
| if (q == &svc->destinations) { |
| q = q->next; |
| continue; |
| } |
| |
| dest = list_entry(q, struct ip_vs_dest, n_list); |
| if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) && |
| atomic_read(&dest->weight) > 0) |
| /* HIT */ |
| goto out; |
| q = q->next; |
| } while (q != p); |
| write_unlock(&svc->sched_lock); |
| return NULL; |
| |
| out: |
| svc->sched_data = q; |
| write_unlock(&svc->sched_lock); |
| IP_VS_DBG(6, "RR: server %u.%u.%u.%u:%u " |
| "activeconns %d refcnt %d weight %d\n", |
| NIPQUAD(dest->addr.ip), ntohs(dest->port), |
| atomic_read(&dest->activeconns), |
| atomic_read(&dest->refcnt), atomic_read(&dest->weight)); |
| |
| return dest; |
| } |
| |
| |
| static struct ip_vs_scheduler ip_vs_rr_scheduler = { |
| .name = "rr", /* name */ |
| .refcnt = ATOMIC_INIT(0), |
| .module = THIS_MODULE, |
| .n_list = LIST_HEAD_INIT(ip_vs_rr_scheduler.n_list), |
| .init_service = ip_vs_rr_init_svc, |
| .update_service = ip_vs_rr_update_svc, |
| .schedule = ip_vs_rr_schedule, |
| }; |
| |
| static int __init ip_vs_rr_init(void) |
| { |
| return register_ip_vs_scheduler(&ip_vs_rr_scheduler); |
| } |
| |
| static void __exit ip_vs_rr_cleanup(void) |
| { |
| unregister_ip_vs_scheduler(&ip_vs_rr_scheduler); |
| } |
| |
| module_init(ip_vs_rr_init); |
| module_exit(ip_vs_rr_cleanup); |
| MODULE_LICENSE("GPL"); |