From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/net/netfilter/ipvs/ip_vs_wrr.c | 270 ++++++++++++++++++++++++++++++++++ 1 file changed, 270 insertions(+) create mode 100644 kernel/net/netfilter/ipvs/ip_vs_wrr.c (limited to 'kernel/net/netfilter/ipvs/ip_vs_wrr.c') diff --git a/kernel/net/netfilter/ipvs/ip_vs_wrr.c b/kernel/net/netfilter/ipvs/ip_vs_wrr.c new file mode 100644 index 000000000..17e6d4406 --- /dev/null +++ b/kernel/net/netfilter/ipvs/ip_vs_wrr.c @@ -0,0 +1,270 @@ +/* + * IPVS: Weighted Round-Robin Scheduling module + * + * Authors: Wensong Zhang + * + * 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_wrr_schedule to return dest + * Wensong Zhang : changed some comestics things for debugging + * Wensong Zhang : changed for the d-linked destination list + * Wensong Zhang : added the ip_vs_wrr_update_svc + * Julian Anastasov : fixed the bug of returning destination + * with weight 0 when all weights are zero + * + */ + +#define KMSG_COMPONENT "IPVS" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include +#include +#include +#include +#include + +#include + +/* The WRR algorithm depends on some caclulations: + * - mw: maximum weight + * - di: weight step, greatest common divisor from all weights + * - cw: current required weight + * As result, all weights are in the [di..mw] range with a step=di. + * + * First, we start with cw = mw and select dests with weight >= cw. + * Then cw is reduced with di and all dests are checked again. + * Last pass should be with cw = di. We have mw/di passes in total: + * + * pass 1: cw = max weight + * pass 2: cw = max weight - di + * pass 3: cw = max weight - 2 * di + * ... + * last pass: cw = di + * + * Weights are supposed to be >= di but we run in parallel with + * weight changes, it is possible some dest weight to be reduced + * below di, bad if it is the only available dest. + * + * So, we modify how mw is calculated, now it is reduced with (di - 1), + * so that last cw is 1 to catch such dests with weight below di: + * pass 1: cw = max weight - (di - 1) + * pass 2: cw = max weight - di - (di - 1) + * pass 3: cw = max weight - 2 * di - (di - 1) + * ... + * last pass: cw = 1 + * + */ + +/* + * current destination pointer for weighted round-robin scheduling + */ +struct ip_vs_wrr_mark { + struct ip_vs_dest *cl; /* current dest or head */ + int cw; /* current weight */ + int mw; /* maximum weight */ + int di; /* decreasing interval */ + struct rcu_head rcu_head; +}; + + +static int ip_vs_wrr_gcd_weight(struct ip_vs_service *svc) +{ + struct ip_vs_dest *dest; + int weight; + int g = 0; + + list_for_each_entry(dest, &svc->destinations, n_list) { + weight = atomic_read(&dest->weight); + if (weight > 0) { + if (g > 0) + g = gcd(weight, g); + else + g = weight; + } + } + return g ? g : 1; +} + + +/* + * Get the maximum weight of the service destinations. + */ +static int ip_vs_wrr_max_weight(struct ip_vs_service *svc) +{ + struct ip_vs_dest *dest; + int new_weight, weight = 0; + + list_for_each_entry(dest, &svc->destinations, n_list) { + new_weight = atomic_read(&dest->weight); + if (new_weight > weight) + weight = new_weight; + } + + return weight; +} + + +static int ip_vs_wrr_init_svc(struct ip_vs_service *svc) +{ + struct ip_vs_wrr_mark *mark; + + /* + * Allocate the mark variable for WRR scheduling + */ + mark = kmalloc(sizeof(struct ip_vs_wrr_mark), GFP_KERNEL); + if (mark == NULL) + return -ENOMEM; + + mark->cl = list_entry(&svc->destinations, struct ip_vs_dest, n_list); + mark->di = ip_vs_wrr_gcd_weight(svc); + mark->mw = ip_vs_wrr_max_weight(svc) - (mark->di - 1); + mark->cw = mark->mw; + svc->sched_data = mark; + + return 0; +} + + +static void ip_vs_wrr_done_svc(struct ip_vs_service *svc) +{ + struct ip_vs_wrr_mark *mark = svc->sched_data; + + /* + * Release the mark variable + */ + kfree_rcu(mark, rcu_head); +} + + +static int ip_vs_wrr_dest_changed(struct ip_vs_service *svc, + struct ip_vs_dest *dest) +{ + struct ip_vs_wrr_mark *mark = svc->sched_data; + + spin_lock_bh(&svc->sched_lock); + mark->cl = list_entry(&svc->destinations, struct ip_vs_dest, n_list); + mark->di = ip_vs_wrr_gcd_weight(svc); + mark->mw = ip_vs_wrr_max_weight(svc) - (mark->di - 1); + if (mark->cw > mark->mw || !mark->cw) + mark->cw = mark->mw; + else if (mark->di > 1) + mark->cw = (mark->cw / mark->di) * mark->di + 1; + spin_unlock_bh(&svc->sched_lock); + return 0; +} + + +/* + * Weighted Round-Robin Scheduling + */ +static struct ip_vs_dest * +ip_vs_wrr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb, + struct ip_vs_iphdr *iph) +{ + struct ip_vs_dest *dest, *last, *stop = NULL; + struct ip_vs_wrr_mark *mark = svc->sched_data; + bool last_pass = false, restarted = false; + + IP_VS_DBG(6, "%s(): Scheduling...\n", __func__); + + spin_lock_bh(&svc->sched_lock); + dest = mark->cl; + /* No available dests? */ + if (mark->mw == 0) + goto err_noavail; + last = dest; + /* Stop only after all dests were checked for weight >= 1 (last pass) */ + while (1) { + list_for_each_entry_continue_rcu(dest, + &svc->destinations, + n_list) { + if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) && + atomic_read(&dest->weight) >= mark->cw) + goto found; + if (dest == stop) + goto err_over; + } + mark->cw -= mark->di; + if (mark->cw <= 0) { + mark->cw = mark->mw; + /* Stop if we tried last pass from first dest: + * 1. last_pass: we started checks when cw > di but + * then all dests were checked for w >= 1 + * 2. last was head: the first and only traversal + * was for weight >= 1, for all dests. + */ + if (last_pass || + &last->n_list == &svc->destinations) + goto err_over; + restarted = true; + } + last_pass = mark->cw <= mark->di; + if (last_pass && restarted && + &last->n_list != &svc->destinations) { + /* First traversal was for w >= 1 but only + * for dests after 'last', now do the same + * for all dests up to 'last'. + */ + stop = last; + } + } + +found: + IP_VS_DBG_BUF(6, "WRR: server %s:%u " + "activeconns %d refcnt %d weight %d\n", + IP_VS_DBG_ADDR(dest->af, &dest->addr), ntohs(dest->port), + atomic_read(&dest->activeconns), + atomic_read(&dest->refcnt), + atomic_read(&dest->weight)); + mark->cl = dest; + + out: + spin_unlock_bh(&svc->sched_lock); + return dest; + +err_noavail: + mark->cl = dest; + dest = NULL; + ip_vs_scheduler_err(svc, "no destination available"); + goto out; + +err_over: + mark->cl = dest; + dest = NULL; + ip_vs_scheduler_err(svc, "no destination available: " + "all destinations are overloaded"); + goto out; +} + + +static struct ip_vs_scheduler ip_vs_wrr_scheduler = { + .name = "wrr", + .refcnt = ATOMIC_INIT(0), + .module = THIS_MODULE, + .n_list = LIST_HEAD_INIT(ip_vs_wrr_scheduler.n_list), + .init_service = ip_vs_wrr_init_svc, + .done_service = ip_vs_wrr_done_svc, + .add_dest = ip_vs_wrr_dest_changed, + .del_dest = ip_vs_wrr_dest_changed, + .upd_dest = ip_vs_wrr_dest_changed, + .schedule = ip_vs_wrr_schedule, +}; + +static int __init ip_vs_wrr_init(void) +{ + return register_ip_vs_scheduler(&ip_vs_wrr_scheduler) ; +} + +static void __exit ip_vs_wrr_cleanup(void) +{ + unregister_ip_vs_scheduler(&ip_vs_wrr_scheduler); + synchronize_rcu(); +} + +module_init(ip_vs_wrr_init); +module_exit(ip_vs_wrr_cleanup); +MODULE_LICENSE("GPL"); -- cgit 1.2.3-korg