2 * IPVS: Least-Connection Scheduling module
4 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 * Wensong Zhang : added the ip_vs_lc_update_svc
13 * Wensong Zhang : added any dest with weight=0 is quiesced
17 #define KMSG_COMPONENT "IPVS"
18 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
20 #include <linux/module.h>
21 #include <linux/kernel.h>
23 #include <net/ip_vs.h>
26 * Least Connection scheduling
28 static struct ip_vs_dest
*
29 ip_vs_lc_schedule(struct ip_vs_service
*svc
, const struct sk_buff
*skb
,
30 struct ip_vs_iphdr
*iph
)
32 struct ip_vs_dest
*dest
, *least
= NULL
;
33 unsigned int loh
= 0, doh
;
35 IP_VS_DBG(6, "%s(): Scheduling...\n", __func__
);
38 * Simply select the server with the least number of
39 * (activeconns<<5) + inactconns
40 * Except whose weight is equal to zero.
41 * If the weight is equal to zero, it means that the server is
42 * quiesced, the existing connections to the server still get
43 * served, but no new connection is assigned to the server.
46 list_for_each_entry_rcu(dest
, &svc
->destinations
, n_list
) {
47 if ((dest
->flags
& IP_VS_DEST_F_OVERLOAD
) ||
48 atomic_read(&dest
->weight
) == 0)
50 doh
= ip_vs_dest_conn_overhead(dest
);
51 if (!least
|| doh
< loh
) {
58 ip_vs_scheduler_err(svc
, "no destination available");
60 IP_VS_DBG_BUF(6, "LC: server %s:%u activeconns %d "
62 IP_VS_DBG_ADDR(least
->af
, &least
->addr
),
64 atomic_read(&least
->activeconns
),
65 atomic_read(&least
->inactconns
));
71 static struct ip_vs_scheduler ip_vs_lc_scheduler
= {
73 .refcnt
= ATOMIC_INIT(0),
74 .module
= THIS_MODULE
,
75 .n_list
= LIST_HEAD_INIT(ip_vs_lc_scheduler
.n_list
),
76 .schedule
= ip_vs_lc_schedule
,
80 static int __init
ip_vs_lc_init(void)
82 return register_ip_vs_scheduler(&ip_vs_lc_scheduler
) ;
85 static void __exit
ip_vs_lc_cleanup(void)
87 unregister_ip_vs_scheduler(&ip_vs_lc_scheduler
);
91 module_init(ip_vs_lc_init
);
92 module_exit(ip_vs_lc_cleanup
);
93 MODULE_LICENSE("GPL");