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 179aada7acSHannes Eder #define KMSG_COMPONENT "IPVS" 189aada7acSHannes Eder #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 199aada7acSHannes Eder 20cb7f6a7bSJulius Volz #include <linux/module.h> 21cb7f6a7bSJulius Volz #include <linux/kernel.h> 22cb7f6a7bSJulius Volz 23cb7f6a7bSJulius Volz #include <net/ip_vs.h> 24cb7f6a7bSJulius Volz 25cb7f6a7bSJulius Volz /* 26cb7f6a7bSJulius Volz * Least Connection scheduling 27cb7f6a7bSJulius Volz */ 28cb7f6a7bSJulius Volz static struct ip_vs_dest * 29cb7f6a7bSJulius Volz ip_vs_lc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb) 30cb7f6a7bSJulius Volz { 31cb7f6a7bSJulius Volz struct ip_vs_dest *dest, *least = NULL; 32cb7f6a7bSJulius Volz unsigned int loh = 0, doh; 33cb7f6a7bSJulius Volz 341e3e238eSHannes Eder IP_VS_DBG(6, "%s(): Scheduling...\n", __func__); 35cb7f6a7bSJulius Volz 36cb7f6a7bSJulius Volz /* 37cb7f6a7bSJulius Volz * Simply select the server with the least number of 38cb7f6a7bSJulius Volz * (activeconns<<5) + inactconns 39cb7f6a7bSJulius Volz * Except whose weight is equal to zero. 40cb7f6a7bSJulius Volz * If the weight is equal to zero, it means that the server is 41cb7f6a7bSJulius Volz * quiesced, the existing connections to the server still get 42cb7f6a7bSJulius Volz * served, but no new connection is assigned to the server. 43cb7f6a7bSJulius Volz */ 44cb7f6a7bSJulius Volz 454ebd288bSJulian Anastasov list_for_each_entry_rcu(dest, &svc->destinations, n_list) { 46cb7f6a7bSJulius Volz if ((dest->flags & IP_VS_DEST_F_OVERLOAD) || 47cb7f6a7bSJulius Volz atomic_read(&dest->weight) == 0) 48cb7f6a7bSJulius Volz continue; 49b552f7e3SChangli Gao doh = ip_vs_dest_conn_overhead(dest); 50cb7f6a7bSJulius Volz if (!least || doh < loh) { 51cb7f6a7bSJulius Volz least = dest; 52cb7f6a7bSJulius Volz loh = doh; 53cb7f6a7bSJulius Volz } 54cb7f6a7bSJulius Volz } 55cb7f6a7bSJulius Volz 5668888d10SSimon Horman if (!least) 5741ac51eeSPatrick Schaaf ip_vs_scheduler_err(svc, "no destination available"); 5868888d10SSimon Horman else 5968888d10SSimon Horman IP_VS_DBG_BUF(6, "LC: server %s:%u activeconns %d " 6068888d10SSimon Horman "inactconns %d\n", 6168888d10SSimon Horman IP_VS_DBG_ADDR(svc->af, &least->addr), 6268888d10SSimon Horman ntohs(least->port), 63cb7f6a7bSJulius Volz atomic_read(&least->activeconns), 64cb7f6a7bSJulius Volz atomic_read(&least->inactconns)); 65cb7f6a7bSJulius Volz 66cb7f6a7bSJulius Volz return least; 67cb7f6a7bSJulius Volz } 68cb7f6a7bSJulius Volz 69cb7f6a7bSJulius Volz 70cb7f6a7bSJulius Volz static struct ip_vs_scheduler ip_vs_lc_scheduler = { 71cb7f6a7bSJulius Volz .name = "lc", 72cb7f6a7bSJulius Volz .refcnt = ATOMIC_INIT(0), 73cb7f6a7bSJulius Volz .module = THIS_MODULE, 74cb7f6a7bSJulius Volz .n_list = LIST_HEAD_INIT(ip_vs_lc_scheduler.n_list), 75cb7f6a7bSJulius Volz .schedule = ip_vs_lc_schedule, 76cb7f6a7bSJulius Volz }; 77cb7f6a7bSJulius Volz 78cb7f6a7bSJulius Volz 79cb7f6a7bSJulius Volz static int __init ip_vs_lc_init(void) 80cb7f6a7bSJulius Volz { 81cb7f6a7bSJulius Volz return register_ip_vs_scheduler(&ip_vs_lc_scheduler) ; 82cb7f6a7bSJulius Volz } 83cb7f6a7bSJulius Volz 84cb7f6a7bSJulius Volz static void __exit ip_vs_lc_cleanup(void) 85cb7f6a7bSJulius Volz { 86cb7f6a7bSJulius Volz unregister_ip_vs_scheduler(&ip_vs_lc_scheduler); 87ceec4c38SJulian Anastasov synchronize_rcu(); 88cb7f6a7bSJulius Volz } 89cb7f6a7bSJulius Volz 90cb7f6a7bSJulius Volz module_init(ip_vs_lc_init); 91cb7f6a7bSJulius Volz module_exit(ip_vs_lc_cleanup); 92cb7f6a7bSJulius Volz MODULE_LICENSE("GPL"); 93