1cb7f6a7bSJulius Volz /* 2cb7f6a7bSJulius Volz * IPVS: Least-Connection Scheduling module 3cb7f6a7bSJulius Volz * 4cb7f6a7bSJulius Volz * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> 5cb7f6a7bSJulius Volz * 6cb7f6a7bSJulius Volz * This program is free software; you can redistribute it and/or 7cb7f6a7bSJulius Volz * modify it under the terms of the GNU General Public License 8cb7f6a7bSJulius Volz * as published by the Free Software Foundation; either version 9cb7f6a7bSJulius Volz * 2 of the License, or (at your option) any later version. 10cb7f6a7bSJulius Volz * 11cb7f6a7bSJulius Volz * Changes: 12cb7f6a7bSJulius Volz * Wensong Zhang : added the ip_vs_lc_update_svc 13cb7f6a7bSJulius Volz * Wensong Zhang : added any dest with weight=0 is quiesced 14cb7f6a7bSJulius Volz * 15cb7f6a7bSJulius Volz */ 16cb7f6a7bSJulius Volz 17cb7f6a7bSJulius Volz #include <linux/module.h> 18cb7f6a7bSJulius Volz #include <linux/kernel.h> 19cb7f6a7bSJulius Volz 20cb7f6a7bSJulius Volz #include <net/ip_vs.h> 21cb7f6a7bSJulius Volz 22cb7f6a7bSJulius Volz 23cb7f6a7bSJulius Volz static inline unsigned int 24cb7f6a7bSJulius Volz ip_vs_lc_dest_overhead(struct ip_vs_dest *dest) 25cb7f6a7bSJulius Volz { 26cb7f6a7bSJulius Volz /* 27cb7f6a7bSJulius Volz * We think the overhead of processing active connections is 256 28cb7f6a7bSJulius Volz * times higher than that of inactive connections in average. (This 29cb7f6a7bSJulius Volz * 256 times might not be accurate, we will change it later) We 30cb7f6a7bSJulius Volz * use the following formula to estimate the overhead now: 31cb7f6a7bSJulius Volz * dest->activeconns*256 + dest->inactconns 32cb7f6a7bSJulius Volz */ 33cb7f6a7bSJulius Volz return (atomic_read(&dest->activeconns) << 8) + 34cb7f6a7bSJulius Volz atomic_read(&dest->inactconns); 35cb7f6a7bSJulius Volz } 36cb7f6a7bSJulius Volz 37cb7f6a7bSJulius Volz 38cb7f6a7bSJulius Volz /* 39cb7f6a7bSJulius Volz * Least Connection scheduling 40cb7f6a7bSJulius Volz */ 41cb7f6a7bSJulius Volz static struct ip_vs_dest * 42cb7f6a7bSJulius Volz ip_vs_lc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb) 43cb7f6a7bSJulius Volz { 44cb7f6a7bSJulius Volz struct ip_vs_dest *dest, *least = NULL; 45cb7f6a7bSJulius Volz unsigned int loh = 0, doh; 46cb7f6a7bSJulius Volz 47cb7f6a7bSJulius Volz IP_VS_DBG(6, "ip_vs_lc_schedule(): Scheduling...\n"); 48cb7f6a7bSJulius Volz 49cb7f6a7bSJulius Volz /* 50cb7f6a7bSJulius Volz * Simply select the server with the least number of 51cb7f6a7bSJulius Volz * (activeconns<<5) + inactconns 52cb7f6a7bSJulius Volz * Except whose weight is equal to zero. 53cb7f6a7bSJulius Volz * If the weight is equal to zero, it means that the server is 54cb7f6a7bSJulius Volz * quiesced, the existing connections to the server still get 55cb7f6a7bSJulius Volz * served, but no new connection is assigned to the server. 56cb7f6a7bSJulius Volz */ 57cb7f6a7bSJulius Volz 58cb7f6a7bSJulius Volz list_for_each_entry(dest, &svc->destinations, n_list) { 59cb7f6a7bSJulius Volz if ((dest->flags & IP_VS_DEST_F_OVERLOAD) || 60cb7f6a7bSJulius Volz atomic_read(&dest->weight) == 0) 61cb7f6a7bSJulius Volz continue; 62cb7f6a7bSJulius Volz doh = ip_vs_lc_dest_overhead(dest); 63cb7f6a7bSJulius Volz if (!least || doh < loh) { 64cb7f6a7bSJulius Volz least = dest; 65cb7f6a7bSJulius Volz loh = doh; 66cb7f6a7bSJulius Volz } 67cb7f6a7bSJulius Volz } 68cb7f6a7bSJulius Volz 69cb7f6a7bSJulius Volz if (least) 70cb7f6a7bSJulius Volz IP_VS_DBG_BUF(6, "LC: server %s:%u activeconns %d inactconns %d\n", 71cb7f6a7bSJulius Volz IP_VS_DBG_ADDR(svc->af, &least->addr), ntohs(least->port), 72cb7f6a7bSJulius Volz atomic_read(&least->activeconns), 73cb7f6a7bSJulius Volz atomic_read(&least->inactconns)); 74cb7f6a7bSJulius Volz 75cb7f6a7bSJulius Volz return least; 76cb7f6a7bSJulius Volz } 77cb7f6a7bSJulius Volz 78cb7f6a7bSJulius Volz 79cb7f6a7bSJulius Volz static struct ip_vs_scheduler ip_vs_lc_scheduler = { 80cb7f6a7bSJulius Volz .name = "lc", 81cb7f6a7bSJulius Volz .refcnt = ATOMIC_INIT(0), 82cb7f6a7bSJulius Volz .module = THIS_MODULE, 83cb7f6a7bSJulius Volz .n_list = LIST_HEAD_INIT(ip_vs_lc_scheduler.n_list), 84cb7f6a7bSJulius Volz #ifdef CONFIG_IP_VS_IPV6 85cb7f6a7bSJulius Volz .supports_ipv6 = 1, 86cb7f6a7bSJulius Volz #endif 87cb7f6a7bSJulius Volz .schedule = ip_vs_lc_schedule, 88cb7f6a7bSJulius Volz }; 89cb7f6a7bSJulius Volz 90cb7f6a7bSJulius Volz 91cb7f6a7bSJulius Volz static int __init ip_vs_lc_init(void) 92cb7f6a7bSJulius Volz { 93cb7f6a7bSJulius Volz return register_ip_vs_scheduler(&ip_vs_lc_scheduler) ; 94cb7f6a7bSJulius Volz } 95cb7f6a7bSJulius Volz 96cb7f6a7bSJulius Volz static void __exit ip_vs_lc_cleanup(void) 97cb7f6a7bSJulius Volz { 98cb7f6a7bSJulius Volz unregister_ip_vs_scheduler(&ip_vs_lc_scheduler); 99cb7f6a7bSJulius Volz } 100cb7f6a7bSJulius Volz 101cb7f6a7bSJulius Volz module_init(ip_vs_lc_init); 102cb7f6a7bSJulius Volz module_exit(ip_vs_lc_cleanup); 103cb7f6a7bSJulius Volz MODULE_LICENSE("GPL"); 104