| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * IPVS: Overflow-Connection Scheduling module |
| * |
| * Authors: Raducu Deaconu <rhadoo_io@yahoo.com> |
| * |
| * Scheduler implements "overflow" loadbalancing according to number of active |
| * connections , will keep all connections to the node with the highest weight |
| * and overflow to the next node if the number of connections exceeds the node's |
| * weight. |
| * Note that this scheduler might not be suitable for UDP because it only uses |
| * active connections |
| */ |
| |
| #define KMSG_COMPONENT "IPVS" |
| #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| |
| #include <net/ip_vs.h> |
| |
| /* OVF Connection scheduling */ |
| static struct ip_vs_dest * |
| ip_vs_ovf_schedule(struct ip_vs_service *svc, const struct sk_buff *skb, |
| struct ip_vs_iphdr *iph) |
| { |
| struct ip_vs_dest *dest, *h = NULL; |
| int hw = 0, w; |
| |
| IP_VS_DBG(6, "ip_vs_ovf_schedule(): Scheduling...\n"); |
| /* select the node with highest weight, go to next in line if active |
| * connections exceed weight |
| */ |
| list_for_each_entry_rcu(dest, &svc->destinations, n_list) { |
| w = atomic_read(&dest->weight); |
| if ((dest->flags & IP_VS_DEST_F_OVERLOAD) || |
| atomic_read(&dest->activeconns) > w || |
| w == 0) |
| continue; |
| if (!h || w > hw) { |
| h = dest; |
| hw = w; |
| } |
| } |
| |
| if (h) { |
| IP_VS_DBG_BUF(6, "OVF: server %s:%u active %d w %d\n", |
| IP_VS_DBG_ADDR(h->af, &h->addr), |
| ntohs(h->port), |
| atomic_read(&h->activeconns), |
| atomic_read(&h->weight)); |
| return h; |
| } |
| |
| ip_vs_scheduler_err(svc, "no destination available"); |
| return NULL; |
| } |
| |
| static struct ip_vs_scheduler ip_vs_ovf_scheduler = { |
| .name = "ovf", |
| .refcnt = ATOMIC_INIT(0), |
| .module = THIS_MODULE, |
| .n_list = LIST_HEAD_INIT(ip_vs_ovf_scheduler.n_list), |
| .schedule = ip_vs_ovf_schedule, |
| }; |
| |
| static int __init ip_vs_ovf_init(void) |
| { |
| return register_ip_vs_scheduler(&ip_vs_ovf_scheduler); |
| } |
| |
| static void __exit ip_vs_ovf_cleanup(void) |
| { |
| unregister_ip_vs_scheduler(&ip_vs_ovf_scheduler); |
| synchronize_rcu(); |
| } |
| |
| module_init(ip_vs_ovf_init); |
| module_exit(ip_vs_ovf_cleanup); |
| MODULE_LICENSE("GPL"); |