152 lines
3.9 KiB
C
152 lines
3.9 KiB
C
/*
|
|
* IPVS: Weighted Least-Connection Scheduling module
|
|
*
|
|
* Version: $Id: ip_vs_wlc.c,v 1.13 2003/04/18 09:03:16 wensong Exp $
|
|
*
|
|
* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
|
|
* Peter Kese <peter.kese@ijs.si>
|
|
*
|
|
* 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.
|
|
*
|
|
* Changes:
|
|
* Wensong Zhang : changed the ip_vs_wlc_schedule to return dest
|
|
* Wensong Zhang : changed to use the inactconns in scheduling
|
|
* Wensong Zhang : changed some comestics things for debugging
|
|
* Wensong Zhang : changed for the d-linked destination list
|
|
* Wensong Zhang : added the ip_vs_wlc_update_svc
|
|
* Wensong Zhang : added any dest with weight=0 is quiesced
|
|
*
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
|
|
#include <net/ip_vs.h>
|
|
|
|
|
|
static int
|
|
ip_vs_wlc_init_svc(struct ip_vs_service *svc)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int
|
|
ip_vs_wlc_done_svc(struct ip_vs_service *svc)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int
|
|
ip_vs_wlc_update_svc(struct ip_vs_service *svc)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
|
|
static inline unsigned int
|
|
ip_vs_wlc_dest_overhead(struct ip_vs_dest *dest)
|
|
{
|
|
/*
|
|
* We think the overhead of processing active connections is 256
|
|
* times higher than that of inactive connections in average. (This
|
|
* 256 times might not be accurate, we will change it later) We
|
|
* use the following formula to estimate the overhead now:
|
|
* dest->activeconns*256 + dest->inactconns
|
|
*/
|
|
return (atomic_read(&dest->activeconns) << 8) +
|
|
atomic_read(&dest->inactconns);
|
|
}
|
|
|
|
|
|
/*
|
|
* Weighted Least Connection scheduling
|
|
*/
|
|
static struct ip_vs_dest *
|
|
ip_vs_wlc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
|
|
{
|
|
struct ip_vs_dest *dest, *least;
|
|
unsigned int loh, doh;
|
|
|
|
IP_VS_DBG(6, "ip_vs_wlc_schedule(): Scheduling...\n");
|
|
|
|
/*
|
|
* We calculate the load of each dest server as follows:
|
|
* (dest overhead) / dest->weight
|
|
*
|
|
* Remember -- no floats in kernel mode!!!
|
|
* The comparison of h1*w2 > h2*w1 is equivalent to that of
|
|
* h1/w1 > h2/w2
|
|
* if every weight is larger than zero.
|
|
*
|
|
* The server with weight=0 is quiesced and will not receive any
|
|
* new connections.
|
|
*/
|
|
|
|
list_for_each_entry(dest, &svc->destinations, n_list) {
|
|
if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) &&
|
|
atomic_read(&dest->weight) > 0) {
|
|
least = dest;
|
|
loh = ip_vs_wlc_dest_overhead(least);
|
|
goto nextstage;
|
|
}
|
|
}
|
|
return NULL;
|
|
|
|
/*
|
|
* Find the destination with the least load.
|
|
*/
|
|
nextstage:
|
|
list_for_each_entry_continue(dest, &svc->destinations, n_list) {
|
|
if (dest->flags & IP_VS_DEST_F_OVERLOAD)
|
|
continue;
|
|
doh = ip_vs_wlc_dest_overhead(dest);
|
|
if (loh * atomic_read(&dest->weight) >
|
|
doh * atomic_read(&least->weight)) {
|
|
least = dest;
|
|
loh = doh;
|
|
}
|
|
}
|
|
|
|
IP_VS_DBG(6, "WLC: server %u.%u.%u.%u:%u "
|
|
"activeconns %d refcnt %d weight %d overhead %d\n",
|
|
NIPQUAD(least->addr), ntohs(least->port),
|
|
atomic_read(&least->activeconns),
|
|
atomic_read(&least->refcnt),
|
|
atomic_read(&least->weight), loh);
|
|
|
|
return least;
|
|
}
|
|
|
|
|
|
static struct ip_vs_scheduler ip_vs_wlc_scheduler =
|
|
{
|
|
.name = "wlc",
|
|
.refcnt = ATOMIC_INIT(0),
|
|
.module = THIS_MODULE,
|
|
.init_service = ip_vs_wlc_init_svc,
|
|
.done_service = ip_vs_wlc_done_svc,
|
|
.update_service = ip_vs_wlc_update_svc,
|
|
.schedule = ip_vs_wlc_schedule,
|
|
};
|
|
|
|
|
|
static int __init ip_vs_wlc_init(void)
|
|
{
|
|
INIT_LIST_HEAD(&ip_vs_wlc_scheduler.n_list);
|
|
return register_ip_vs_scheduler(&ip_vs_wlc_scheduler);
|
|
}
|
|
|
|
static void __exit ip_vs_wlc_cleanup(void)
|
|
{
|
|
unregister_ip_vs_scheduler(&ip_vs_wlc_scheduler);
|
|
}
|
|
|
|
module_init(ip_vs_wlc_init);
|
|
module_exit(ip_vs_wlc_cleanup);
|
|
MODULE_LICENSE("GPL");
|