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1da177e4 LT |
1 | /* |
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 | ||
30 | static int ip_vs_rr_init_svc(struct ip_vs_service *svc) | |
31 | { | |
32 | svc->sched_data = &svc->destinations; | |
33 | return 0; | |
34 | } | |
35 | ||
36 | ||
37 | static int ip_vs_rr_done_svc(struct ip_vs_service *svc) | |
38 | { | |
39 | return 0; | |
40 | } | |
41 | ||
42 | ||
43 | static 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 | */ | |
53 | static struct ip_vs_dest * | |
54 | ip_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 | } | |
e905a9ed | 71 | |
1da177e4 LT |
72 | 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 | ||
95 | static 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 | ||
105 | static 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 | ||
111 | static void __exit ip_vs_rr_cleanup(void) | |
112 | { | |
113 | unregister_ip_vs_scheduler(&ip_vs_rr_scheduler); | |
114 | } | |
115 | ||
116 | module_init(ip_vs_rr_init); | |
117 | module_exit(ip_vs_rr_cleanup); | |
118 | MODULE_LICENSE("GPL"); |