124 lines
3.1 KiB
C
124 lines
3.1 KiB
C
/*
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* IPVS: Least-Connection Scheduling module
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*
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* Version: $Id: ip_vs_lc.c,v 1.10 2003/04/18 09:03:16 wensong Exp $
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*
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* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Changes:
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* Wensong Zhang : added the ip_vs_lc_update_svc
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* Wensong Zhang : added any dest with weight=0 is quiesced
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <net/ip_vs.h>
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static int ip_vs_lc_init_svc(struct ip_vs_service *svc)
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{
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return 0;
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}
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static int ip_vs_lc_done_svc(struct ip_vs_service *svc)
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{
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return 0;
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}
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static int ip_vs_lc_update_svc(struct ip_vs_service *svc)
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{
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return 0;
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}
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static inline unsigned int
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ip_vs_lc_dest_overhead(struct ip_vs_dest *dest)
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{
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/*
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* We think the overhead of processing active connections is 256
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* times higher than that of inactive connections in average. (This
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* 256 times might not be accurate, we will change it later) We
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* use the following formula to estimate the overhead now:
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* dest->activeconns*256 + dest->inactconns
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*/
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return (atomic_read(&dest->activeconns) << 8) +
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atomic_read(&dest->inactconns);
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}
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/*
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* Least Connection scheduling
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*/
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static struct ip_vs_dest *
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ip_vs_lc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
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{
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struct ip_vs_dest *dest, *least = NULL;
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unsigned int loh = 0, doh;
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IP_VS_DBG(6, "ip_vs_lc_schedule(): Scheduling...\n");
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/*
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* Simply select the server with the least number of
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* (activeconns<<5) + inactconns
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* Except whose weight is equal to zero.
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* If the weight is equal to zero, it means that the server is
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* quiesced, the existing connections to the server still get
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* served, but no new connection is assigned to the server.
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*/
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list_for_each_entry(dest, &svc->destinations, n_list) {
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if ((dest->flags & IP_VS_DEST_F_OVERLOAD) ||
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atomic_read(&dest->weight) == 0)
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continue;
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doh = ip_vs_lc_dest_overhead(dest);
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if (!least || doh < loh) {
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least = dest;
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loh = doh;
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}
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}
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if (least)
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IP_VS_DBG(6, "LC: server %u.%u.%u.%u:%u activeconns %d inactconns %d\n",
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NIPQUAD(least->addr), ntohs(least->port),
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atomic_read(&least->activeconns),
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atomic_read(&least->inactconns));
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return least;
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}
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static struct ip_vs_scheduler ip_vs_lc_scheduler = {
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.name = "lc",
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.refcnt = ATOMIC_INIT(0),
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.module = THIS_MODULE,
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.init_service = ip_vs_lc_init_svc,
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.done_service = ip_vs_lc_done_svc,
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.update_service = ip_vs_lc_update_svc,
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.schedule = ip_vs_lc_schedule,
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};
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static int __init ip_vs_lc_init(void)
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{
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INIT_LIST_HEAD(&ip_vs_lc_scheduler.n_list);
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return register_ip_vs_scheduler(&ip_vs_lc_scheduler) ;
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}
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static void __exit ip_vs_lc_cleanup(void)
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{
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unregister_ip_vs_scheduler(&ip_vs_lc_scheduler);
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}
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module_init(ip_vs_lc_init);
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module_exit(ip_vs_lc_cleanup);
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MODULE_LICENSE("GPL");
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