2 * IPVS: Round-Robin Scheduling module
4 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
5 * Peter Kese <peter.kese@ijs.si>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
13 * Wensong Zhang : changed the ip_vs_rr_schedule to return dest
14 * Julian Anastasov : fixed the NULL pointer access bug in debugging
15 * Wensong Zhang : changed some comestics things for debugging
16 * Wensong Zhang : changed for the d-linked destination list
17 * Wensong Zhang : added the ip_vs_rr_update_svc
18 * Wensong Zhang : added any dest with weight=0 is quiesced
22 #define KMSG_COMPONENT "IPVS"
23 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
25 #include <linux/module.h>
26 #include <linux/kernel.h>
28 #include <net/ip_vs.h>
31 static int ip_vs_rr_init_svc(struct ip_vs_service
*svc
)
33 svc
->sched_data
= &svc
->destinations
;
38 static int ip_vs_rr_update_svc(struct ip_vs_service
*svc
)
40 svc
->sched_data
= &svc
->destinations
;
46 * Round-Robin Scheduling
48 static struct ip_vs_dest
*
49 ip_vs_rr_schedule(struct ip_vs_service
*svc
, const struct sk_buff
*skb
)
51 struct list_head
*p
, *q
;
52 struct ip_vs_dest
*dest
;
54 IP_VS_DBG(6, "%s(): Scheduling...\n", __func__
);
56 write_lock(&svc
->sched_lock
);
57 p
= (struct list_head
*)svc
->sched_data
;
62 if (q
== &svc
->destinations
) {
67 dest
= list_entry(q
, struct ip_vs_dest
, n_list
);
68 if (!(dest
->flags
& IP_VS_DEST_F_OVERLOAD
) &&
69 atomic_read(&dest
->weight
) > 0)
74 write_unlock(&svc
->sched_lock
);
75 ip_vs_scheduler_err(svc
, "no destination available");
80 write_unlock(&svc
->sched_lock
);
81 IP_VS_DBG_BUF(6, "RR: server %s:%u "
82 "activeconns %d refcnt %d weight %d\n",
83 IP_VS_DBG_ADDR(svc
->af
, &dest
->addr
), ntohs(dest
->port
),
84 atomic_read(&dest
->activeconns
),
85 atomic_read(&dest
->refcnt
), atomic_read(&dest
->weight
));
91 static struct ip_vs_scheduler ip_vs_rr_scheduler
= {
92 .name
= "rr", /* name */
93 .refcnt
= ATOMIC_INIT(0),
94 .module
= THIS_MODULE
,
95 .n_list
= LIST_HEAD_INIT(ip_vs_rr_scheduler
.n_list
),
96 .init_service
= ip_vs_rr_init_svc
,
97 .update_service
= ip_vs_rr_update_svc
,
98 .schedule
= ip_vs_rr_schedule
,
101 static int __init
ip_vs_rr_init(void)
103 return register_ip_vs_scheduler(&ip_vs_rr_scheduler
);
106 static void __exit
ip_vs_rr_cleanup(void)
108 unregister_ip_vs_scheduler(&ip_vs_rr_scheduler
);
111 module_init(ip_vs_rr_init
);
112 module_exit(ip_vs_rr_cleanup
);
113 MODULE_LICENSE("GPL");