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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
111 lines
3 KiB
C
111 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* IPVS: Weighted Least-Connection Scheduling module
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*
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* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
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* Peter Kese <peter.kese@ijs.si>
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*
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* Changes:
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* Wensong Zhang : changed the ip_vs_wlc_schedule to return dest
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* Wensong Zhang : changed to use the inactconns in scheduling
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* Wensong Zhang : changed some comestics things for debugging
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* Wensong Zhang : changed for the d-linked destination list
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* Wensong Zhang : added the ip_vs_wlc_update_svc
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* Wensong Zhang : added any dest with weight=0 is quiesced
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*/
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#define KMSG_COMPONENT "IPVS"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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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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/*
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* Weighted Least Connection scheduling
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*/
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static struct ip_vs_dest *
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ip_vs_wlc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb,
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struct ip_vs_iphdr *iph)
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{
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struct ip_vs_dest *dest, *least;
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int loh, doh;
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IP_VS_DBG(6, "ip_vs_wlc_schedule(): Scheduling...\n");
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/*
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* We calculate the load of each dest server as follows:
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* (dest overhead) / dest->weight
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*
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* Remember -- no floats in kernel mode!!!
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* The comparison of h1*w2 > h2*w1 is equivalent to that of
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* h1/w1 > h2/w2
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* if every weight is larger than zero.
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*
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* The server with weight=0 is quiesced and will not receive any
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* new connections.
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*/
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list_for_each_entry_rcu(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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least = dest;
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loh = ip_vs_dest_conn_overhead(least);
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goto nextstage;
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}
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}
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ip_vs_scheduler_err(svc, "no destination available");
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return NULL;
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/*
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* Find the destination with the least load.
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*/
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nextstage:
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list_for_each_entry_continue_rcu(dest, &svc->destinations, n_list) {
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if (dest->flags & IP_VS_DEST_F_OVERLOAD)
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continue;
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doh = ip_vs_dest_conn_overhead(dest);
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if ((__s64)loh * atomic_read(&dest->weight) >
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(__s64)doh * atomic_read(&least->weight)) {
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least = dest;
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loh = doh;
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}
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}
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IP_VS_DBG_BUF(6, "WLC: server %s:%u "
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"activeconns %d refcnt %d weight %d overhead %d\n",
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IP_VS_DBG_ADDR(least->af, &least->addr),
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ntohs(least->port),
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atomic_read(&least->activeconns),
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refcount_read(&least->refcnt),
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atomic_read(&least->weight), loh);
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return least;
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}
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static struct ip_vs_scheduler ip_vs_wlc_scheduler =
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{
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.name = "wlc",
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.refcnt = ATOMIC_INIT(0),
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.module = THIS_MODULE,
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.n_list = LIST_HEAD_INIT(ip_vs_wlc_scheduler.n_list),
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.schedule = ip_vs_wlc_schedule,
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};
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static int __init ip_vs_wlc_init(void)
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{
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return register_ip_vs_scheduler(&ip_vs_wlc_scheduler);
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}
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static void __exit ip_vs_wlc_cleanup(void)
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{
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unregister_ip_vs_scheduler(&ip_vs_wlc_scheduler);
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synchronize_rcu();
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}
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module_init(ip_vs_wlc_init);
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module_exit(ip_vs_wlc_cleanup);
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MODULE_LICENSE("GPL");
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