]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * IPVS: Least-Connection Scheduling module | |
3 | * | |
4 | * Version: $Id: ip_vs_lc.c,v 1.10 2003/04/18 09:03:16 wensong Exp $ | |
5 | * | |
6 | * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License | |
10 | * as published by the Free Software Foundation; either version | |
11 | * 2 of the License, or (at your option) any later version. | |
12 | * | |
13 | * Changes: | |
14 | * Wensong Zhang : added the ip_vs_lc_update_svc | |
15 | * Wensong Zhang : added any dest with weight=0 is quiesced | |
16 | * | |
17 | */ | |
18 | ||
19 | #include <linux/module.h> | |
20 | #include <linux/kernel.h> | |
21 | ||
22 | #include <net/ip_vs.h> | |
23 | ||
24 | ||
25 | static int ip_vs_lc_init_svc(struct ip_vs_service *svc) | |
26 | { | |
27 | return 0; | |
28 | } | |
29 | ||
30 | ||
31 | static int ip_vs_lc_done_svc(struct ip_vs_service *svc) | |
32 | { | |
33 | return 0; | |
34 | } | |
35 | ||
36 | ||
37 | static int ip_vs_lc_update_svc(struct ip_vs_service *svc) | |
38 | { | |
39 | return 0; | |
40 | } | |
41 | ||
42 | ||
43 | static inline unsigned int | |
44 | ip_vs_lc_dest_overhead(struct ip_vs_dest *dest) | |
45 | { | |
46 | /* | |
47 | * We think the overhead of processing active connections is 256 | |
48 | * times higher than that of inactive connections in average. (This | |
49 | * 256 times might not be accurate, we will change it later) We | |
50 | * use the following formula to estimate the overhead now: | |
51 | * dest->activeconns*256 + dest->inactconns | |
52 | */ | |
53 | return (atomic_read(&dest->activeconns) << 8) + | |
54 | atomic_read(&dest->inactconns); | |
55 | } | |
56 | ||
57 | ||
58 | /* | |
59 | * Least Connection scheduling | |
60 | */ | |
61 | static struct ip_vs_dest * | |
62 | ip_vs_lc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb) | |
63 | { | |
64 | struct ip_vs_dest *dest, *least = NULL; | |
65 | unsigned int loh = 0, doh; | |
66 | ||
67 | IP_VS_DBG(6, "ip_vs_lc_schedule(): Scheduling...\n"); | |
68 | ||
69 | /* | |
70 | * Simply select the server with the least number of | |
71 | * (activeconns<<5) + inactconns | |
72 | * Except whose weight is equal to zero. | |
73 | * If the weight is equal to zero, it means that the server is | |
74 | * quiesced, the existing connections to the server still get | |
75 | * served, but no new connection is assigned to the server. | |
76 | */ | |
77 | ||
78 | list_for_each_entry(dest, &svc->destinations, n_list) { | |
79 | if ((dest->flags & IP_VS_DEST_F_OVERLOAD) || | |
80 | atomic_read(&dest->weight) == 0) | |
81 | continue; | |
82 | doh = ip_vs_lc_dest_overhead(dest); | |
83 | if (!least || doh < loh) { | |
84 | least = dest; | |
85 | loh = doh; | |
86 | } | |
87 | } | |
88 | ||
89 | if (least) | |
90 | IP_VS_DBG(6, "LC: server %u.%u.%u.%u:%u activeconns %d inactconns %d\n", | |
91 | NIPQUAD(least->addr), ntohs(least->port), | |
92 | atomic_read(&least->activeconns), | |
93 | atomic_read(&least->inactconns)); | |
94 | ||
95 | return least; | |
96 | } | |
97 | ||
98 | ||
99 | static struct ip_vs_scheduler ip_vs_lc_scheduler = { | |
100 | .name = "lc", | |
101 | .refcnt = ATOMIC_INIT(0), | |
102 | .module = THIS_MODULE, | |
103 | .init_service = ip_vs_lc_init_svc, | |
104 | .done_service = ip_vs_lc_done_svc, | |
105 | .update_service = ip_vs_lc_update_svc, | |
106 | .schedule = ip_vs_lc_schedule, | |
107 | }; | |
108 | ||
109 | ||
110 | static int __init ip_vs_lc_init(void) | |
111 | { | |
112 | INIT_LIST_HEAD(&ip_vs_lc_scheduler.n_list); | |
113 | return register_ip_vs_scheduler(&ip_vs_lc_scheduler) ; | |
114 | } | |
115 | ||
116 | static void __exit ip_vs_lc_cleanup(void) | |
117 | { | |
118 | unregister_ip_vs_scheduler(&ip_vs_lc_scheduler); | |
119 | } | |
120 | ||
121 | module_init(ip_vs_lc_init); | |
122 | module_exit(ip_vs_lc_cleanup); | |
123 | MODULE_LICENSE("GPL"); |