blob: 433f8a947924fa1b17091e0f9b8f292570dafcbf [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * IPVS: Round-Robin Scheduling module
3 *
4 * Version: $Id: ip_vs_rr.c,v 1.9 2002/09/15 08:14:08 wensong Exp $
5 *
6 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
7 * Peter Kese <peter.kese@ijs.si>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 *
14 * Fixes/Changes:
15 * Wensong Zhang : changed the ip_vs_rr_schedule to return dest
16 * Julian Anastasov : fixed the NULL pointer access bug in debugging
17 * Wensong Zhang : changed some comestics things for debugging
18 * Wensong Zhang : changed for the d-linked destination list
19 * Wensong Zhang : added the ip_vs_rr_update_svc
20 * Wensong Zhang : added any dest with weight=0 is quiesced
21 *
22 */
23
24#include <linux/module.h>
25#include <linux/kernel.h>
26
27#include <net/ip_vs.h>
28
29
30static int ip_vs_rr_init_svc(struct ip_vs_service *svc)
31{
32 svc->sched_data = &svc->destinations;
33 return 0;
34}
35
36
37static int ip_vs_rr_done_svc(struct ip_vs_service *svc)
38{
39 return 0;
40}
41
42
43static int ip_vs_rr_update_svc(struct ip_vs_service *svc)
44{
45 svc->sched_data = &svc->destinations;
46 return 0;
47}
48
49
50/*
51 * Round-Robin Scheduling
52 */
53static struct ip_vs_dest *
54ip_vs_rr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
55{
56 struct list_head *p, *q;
57 struct ip_vs_dest *dest;
58
59 IP_VS_DBG(6, "ip_vs_rr_schedule(): Scheduling...\n");
60
61 write_lock(&svc->sched_lock);
62 p = (struct list_head *)svc->sched_data;
63 p = p->next;
64 q = p;
65 do {
66 /* skip list head */
67 if (q == &svc->destinations) {
68 q = q->next;
69 continue;
70 }
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090071
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 dest = list_entry(q, struct ip_vs_dest, n_list);
73 if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) &&
74 atomic_read(&dest->weight) > 0)
75 /* HIT */
76 goto out;
77 q = q->next;
78 } while (q != p);
79 write_unlock(&svc->sched_lock);
80 return NULL;
81
82 out:
83 svc->sched_data = q;
84 write_unlock(&svc->sched_lock);
85 IP_VS_DBG(6, "RR: server %u.%u.%u.%u:%u "
86 "activeconns %d refcnt %d weight %d\n",
87 NIPQUAD(dest->addr), ntohs(dest->port),
88 atomic_read(&dest->activeconns),
89 atomic_read(&dest->refcnt), atomic_read(&dest->weight));
90
91 return dest;
92}
93
94
95static struct ip_vs_scheduler ip_vs_rr_scheduler = {
96 .name = "rr", /* name */
97 .refcnt = ATOMIC_INIT(0),
98 .module = THIS_MODULE,
99 .init_service = ip_vs_rr_init_svc,
100 .done_service = ip_vs_rr_done_svc,
101 .update_service = ip_vs_rr_update_svc,
102 .schedule = ip_vs_rr_schedule,
103};
104
105static int __init ip_vs_rr_init(void)
106{
107 INIT_LIST_HEAD(&ip_vs_rr_scheduler.n_list);
108 return register_ip_vs_scheduler(&ip_vs_rr_scheduler);
109}
110
111static void __exit ip_vs_rr_cleanup(void)
112{
113 unregister_ip_vs_scheduler(&ip_vs_rr_scheduler);
114}
115
116module_init(ip_vs_rr_init);
117module_exit(ip_vs_rr_cleanup);
118MODULE_LICENSE("GPL");