projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * IPVS: Least-Connection Scheduling module | |
| 3 | * | |
| 1da177e4 LT |
4 | * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> |
| 5 | * | |
| 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. | |
| 10 | * | |
| 11 | * Changes: | |
| 12 | * Wensong Zhang : added the ip_vs_lc_update_svc | |
| 13 | * Wensong Zhang : added any dest with weight=0 is quiesced | |
| 14 | * | |
| 15 | */ | |
| 16 | ||
| 17 | #include <linux/module.h> | |
| 18 | #include <linux/kernel.h> | |
| 19 | ||
| 20 | #include <net/ip_vs.h> | |
| 21 | ||
| 22 | ||
| 1da177e4 LT |
23 | static inline unsigned int |
| 24 | ip_vs_lc_dest_overhead(struct ip_vs_dest *dest) | |
| 25 | { | |
| 26 | /* | |
| 27 | * We think the overhead of processing active connections is 256 | |
| 28 | * times higher than that of inactive connections in average. (This | |
| 29 | * 256 times might not be accurate, we will change it later) We | |
| 30 | * use the following formula to estimate the overhead now: | |
| 31 | * dest->activeconns*256 + dest->inactconns | |
| 32 | */ | |
| 33 | return (atomic_read(&dest->activeconns) << 8) + | |
| 34 | atomic_read(&dest->inactconns); | |
| 35 | } | |
| 36 | ||
| 37 | ||
| 38 | /* | |
| 39 | * Least Connection scheduling | |
| 40 | */ | |
| 41 | static struct ip_vs_dest * | |
| 42 | ip_vs_lc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb) | |
| 43 | { | |
| 44 | struct ip_vs_dest *dest, *least = NULL; | |
| 45 | unsigned int loh = 0, doh; | |
| 46 | ||
| 47 | IP_VS_DBG(6, "ip_vs_lc_schedule(): Scheduling...\n"); | |
| 48 | ||
| 49 | /* | |
| 50 | * Simply select the server with the least number of | |
| 51 | * (activeconns<<5) + inactconns | |
| 52 | * Except whose weight is equal to zero. | |
| 53 | * If the weight is equal to zero, it means that the server is | |
| 54 | * quiesced, the existing connections to the server still get | |
| 55 | * served, but no new connection is assigned to the server. | |
| 56 | */ | |
| 57 | ||
| 58 | list_for_each_entry(dest, &svc->destinations, n_list) { | |
| 59 | if ((dest->flags & IP_VS_DEST_F_OVERLOAD) || | |
| 60 | atomic_read(&dest->weight) == 0) | |
| 61 | continue; | |
| 62 | doh = ip_vs_lc_dest_overhead(dest); | |
| 63 | if (!least || doh < loh) { | |
| 64 | least = dest; | |
| 65 | loh = doh; | |
| 66 | } | |
| 67 | } | |
| 68 | ||
| 68888d10 SH |
69 | if (!least) |
| 70 | IP_VS_ERR_RL("LC: no destination available\n"); | |
| 71 | else | |
| 72 | IP_VS_DBG_BUF(6, "LC: server %s:%u activeconns %d " | |
| 73 | "inactconns %d\n", | |
| 74 | IP_VS_DBG_ADDR(svc->af, &least->addr), | |
| 75 | ntohs(least->port), | |
| 76 | atomic_read(&least->activeconns), | |
| 77 | atomic_read(&least->inactconns)); | |
| 1da177e4 LT |
78 | |
| 79 | return least; | |
| 80 | } | |
| 81 | ||
| 82 | ||
| 83 | static struct ip_vs_scheduler ip_vs_lc_scheduler = { | |
| 84 | .name = "lc", | |
| 85 | .refcnt = ATOMIC_INIT(0), | |
| 86 | .module = THIS_MODULE, | |
| d149ccc9 | 87 | .n_list = LIST_HEAD_INIT(ip_vs_lc_scheduler.n_list), |
| 1da177e4 LT |
88 | .schedule = ip_vs_lc_schedule, |
| 89 | }; | |
| 90 | ||
| 91 | ||
| 92 | static int __init ip_vs_lc_init(void) | |
| 93 | { | |
| 1da177e4 LT |
94 | return register_ip_vs_scheduler(&ip_vs_lc_scheduler) ; |
| 95 | } | |
| 96 | ||
| 97 | static void __exit ip_vs_lc_cleanup(void) | |
| 98 | { | |
| 99 | unregister_ip_vs_scheduler(&ip_vs_lc_scheduler); | |
| 100 | } | |
| 101 | ||
| 102 | module_init(ip_vs_lc_init); | |
| 103 | module_exit(ip_vs_lc_cleanup); | |
| 104 | MODULE_LICENSE("GPL"); |