summaryrefslogtreecommitdiff
path: root/net/ipv4/ipvs/ip_vs_lblc.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/ipv4/ipvs/ip_vs_lblc.c')
-rw-r--r--net/ipv4/ipvs/ip_vs_lblc.c624
1 files changed, 624 insertions, 0 deletions
diff --git a/net/ipv4/ipvs/ip_vs_lblc.c b/net/ipv4/ipvs/ip_vs_lblc.c
new file mode 100644
index 00000000000..c035838b780
--- /dev/null
+++ b/net/ipv4/ipvs/ip_vs_lblc.c
@@ -0,0 +1,624 @@
+/*
+ * IPVS: Locality-Based Least-Connection scheduling module
+ *
+ * Version: $Id: ip_vs_lblc.c,v 1.10 2002/09/15 08:14:08 wensong Exp $
+ *
+ * Authors: Wensong Zhang <wensong@gnuchina.org>
+ *
+ * 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:
+ * Martin Hamilton : fixed the terrible locking bugs
+ * *lock(tbl->lock) ==> *lock(&tbl->lock)
+ * Wensong Zhang : fixed the uninitilized tbl->lock bug
+ * Wensong Zhang : added doing full expiration check to
+ * collect stale entries of 24+ hours when
+ * no partial expire check in a half hour
+ * Julian Anastasov : replaced del_timer call with del_timer_sync
+ * to avoid the possible race between timer
+ * handler and del_timer thread in SMP
+ *
+ */
+
+/*
+ * The lblc algorithm is as follows (pseudo code):
+ *
+ * if cachenode[dest_ip] is null then
+ * n, cachenode[dest_ip] <- {weighted least-conn node};
+ * else
+ * n <- cachenode[dest_ip];
+ * if (n is dead) OR
+ * (n.conns>n.weight AND
+ * there is a node m with m.conns<m.weight/2) then
+ * n, cachenode[dest_ip] <- {weighted least-conn node};
+ *
+ * return n;
+ *
+ * Thanks must go to Wenzhuo Zhang for talking WCCP to me and pushing
+ * me to write this module.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+/* for sysctl */
+#include <linux/fs.h>
+#include <linux/sysctl.h>
+
+#include <net/ip_vs.h>
+
+
+/*
+ * It is for garbage collection of stale IPVS lblc entries,
+ * when the table is full.
+ */
+#define CHECK_EXPIRE_INTERVAL (60*HZ)
+#define ENTRY_TIMEOUT (6*60*HZ)
+
+/*
+ * It is for full expiration check.
+ * When there is no partial expiration check (garbage collection)
+ * in a half hour, do a full expiration check to collect stale
+ * entries that haven't been touched for a day.
+ */
+#define COUNT_FOR_FULL_EXPIRATION 30
+static int sysctl_ip_vs_lblc_expiration = 24*60*60*HZ;
+
+
+/*
+ * for IPVS lblc entry hash table
+ */
+#ifndef CONFIG_IP_VS_LBLC_TAB_BITS
+#define CONFIG_IP_VS_LBLC_TAB_BITS 10
+#endif
+#define IP_VS_LBLC_TAB_BITS CONFIG_IP_VS_LBLC_TAB_BITS
+#define IP_VS_LBLC_TAB_SIZE (1 << IP_VS_LBLC_TAB_BITS)
+#define IP_VS_LBLC_TAB_MASK (IP_VS_LBLC_TAB_SIZE - 1)
+
+
+/*
+ * IPVS lblc entry represents an association between destination
+ * IP address and its destination server
+ */
+struct ip_vs_lblc_entry {
+ struct list_head list;
+ __u32 addr; /* destination IP address */
+ struct ip_vs_dest *dest; /* real server (cache) */
+ unsigned long lastuse; /* last used time */
+};
+
+
+/*
+ * IPVS lblc hash table
+ */
+struct ip_vs_lblc_table {
+ rwlock_t lock; /* lock for this table */
+ struct list_head bucket[IP_VS_LBLC_TAB_SIZE]; /* hash bucket */
+ atomic_t entries; /* number of entries */
+ int max_size; /* maximum size of entries */
+ struct timer_list periodic_timer; /* collect stale entries */
+ int rover; /* rover for expire check */
+ int counter; /* counter for no expire */
+};
+
+
+/*
+ * IPVS LBLC sysctl table
+ */
+
+static ctl_table vs_vars_table[] = {
+ {
+ .ctl_name = NET_IPV4_VS_LBLC_EXPIRE,
+ .procname = "lblc_expiration",
+ .data = &sysctl_ip_vs_lblc_expiration,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_jiffies,
+ },
+ { .ctl_name = 0 }
+};
+
+static ctl_table vs_table[] = {
+ {
+ .ctl_name = NET_IPV4_VS,
+ .procname = "vs",
+ .mode = 0555,
+ .child = vs_vars_table
+ },
+ { .ctl_name = 0 }
+};
+
+static ctl_table ipv4_table[] = {
+ {
+ .ctl_name = NET_IPV4,
+ .procname = "ipv4",
+ .mode = 0555,
+ .child = vs_table
+ },
+ { .ctl_name = 0 }
+};
+
+static ctl_table lblc_root_table[] = {
+ {
+ .ctl_name = CTL_NET,
+ .procname = "net",
+ .mode = 0555,
+ .child = ipv4_table
+ },
+ { .ctl_name = 0 }
+};
+
+static struct ctl_table_header * sysctl_header;
+
+/*
+ * new/free a ip_vs_lblc_entry, which is a mapping of a destionation
+ * IP address to a server.
+ */
+static inline struct ip_vs_lblc_entry *
+ip_vs_lblc_new(__u32 daddr, struct ip_vs_dest *dest)
+{
+ struct ip_vs_lblc_entry *en;
+
+ en = kmalloc(sizeof(struct ip_vs_lblc_entry), GFP_ATOMIC);
+ if (en == NULL) {
+ IP_VS_ERR("ip_vs_lblc_new(): no memory\n");
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&en->list);
+ en->addr = daddr;
+
+ atomic_inc(&dest->refcnt);
+ en->dest = dest;
+
+ return en;
+}
+
+
+static inline void ip_vs_lblc_free(struct ip_vs_lblc_entry *en)
+{
+ list_del(&en->list);
+ /*
+ * We don't kfree dest because it is refered either by its service
+ * or the trash dest list.
+ */
+ atomic_dec(&en->dest->refcnt);
+ kfree(en);
+}
+
+
+/*
+ * Returns hash value for IPVS LBLC entry
+ */
+static inline unsigned ip_vs_lblc_hashkey(__u32 addr)
+{
+ return (ntohl(addr)*2654435761UL) & IP_VS_LBLC_TAB_MASK;
+}
+
+
+/*
+ * Hash an entry in the ip_vs_lblc_table.
+ * returns bool success.
+ */
+static int
+ip_vs_lblc_hash(struct ip_vs_lblc_table *tbl, struct ip_vs_lblc_entry *en)
+{
+ unsigned hash;
+
+ if (!list_empty(&en->list)) {
+ IP_VS_ERR("ip_vs_lblc_hash(): request for already hashed, "
+ "called from %p\n", __builtin_return_address(0));
+ return 0;
+ }
+
+ /*
+ * Hash by destination IP address
+ */
+ hash = ip_vs_lblc_hashkey(en->addr);
+
+ write_lock(&tbl->lock);
+ list_add(&en->list, &tbl->bucket[hash]);
+ atomic_inc(&tbl->entries);
+ write_unlock(&tbl->lock);
+
+ return 1;
+}
+
+
+#if 0000
+/*
+ * Unhash ip_vs_lblc_entry from ip_vs_lblc_table.
+ * returns bool success.
+ */
+static int ip_vs_lblc_unhash(struct ip_vs_lblc_table *tbl,
+ struct ip_vs_lblc_entry *en)
+{
+ if (list_empty(&en->list)) {
+ IP_VS_ERR("ip_vs_lblc_unhash(): request for not hashed entry, "
+ "called from %p\n", __builtin_return_address(0));
+ return 0;
+ }
+
+ /*
+ * Remove it from the table
+ */
+ write_lock(&tbl->lock);
+ list_del(&en->list);
+ INIT_LIST_HEAD(&en->list);
+ write_unlock(&tbl->lock);
+
+ return 1;
+}
+#endif
+
+
+/*
+ * Get ip_vs_lblc_entry associated with supplied parameters.
+ */
+static inline struct ip_vs_lblc_entry *
+ip_vs_lblc_get(struct ip_vs_lblc_table *tbl, __u32 addr)
+{
+ unsigned hash;
+ struct ip_vs_lblc_entry *en;
+
+ hash = ip_vs_lblc_hashkey(addr);
+
+ read_lock(&tbl->lock);
+
+ list_for_each_entry(en, &tbl->bucket[hash], list) {
+ if (en->addr == addr) {
+ /* HIT */
+ read_unlock(&tbl->lock);
+ return en;
+ }
+ }
+
+ read_unlock(&tbl->lock);
+
+ return NULL;
+}
+
+
+/*
+ * Flush all the entries of the specified table.
+ */
+static void ip_vs_lblc_flush(struct ip_vs_lblc_table *tbl)
+{
+ int i;
+ struct ip_vs_lblc_entry *en, *nxt;
+
+ for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) {
+ write_lock(&tbl->lock);
+ list_for_each_entry_safe(en, nxt, &tbl->bucket[i], list) {
+ ip_vs_lblc_free(en);
+ atomic_dec(&tbl->entries);
+ }
+ write_unlock(&tbl->lock);
+ }
+}
+
+
+static inline void ip_vs_lblc_full_check(struct ip_vs_lblc_table *tbl)
+{
+ unsigned long now = jiffies;
+ int i, j;
+ struct ip_vs_lblc_entry *en, *nxt;
+
+ for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) {
+ j = (j + 1) & IP_VS_LBLC_TAB_MASK;
+
+ write_lock(&tbl->lock);
+ list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
+ if (time_before(now,
+ en->lastuse + sysctl_ip_vs_lblc_expiration))
+ continue;
+
+ ip_vs_lblc_free(en);
+ atomic_dec(&tbl->entries);
+ }
+ write_unlock(&tbl->lock);
+ }
+ tbl->rover = j;
+}
+
+
+/*
+ * Periodical timer handler for IPVS lblc table
+ * It is used to collect stale entries when the number of entries
+ * exceeds the maximum size of the table.
+ *
+ * Fixme: we probably need more complicated algorithm to collect
+ * entries that have not been used for a long time even
+ * if the number of entries doesn't exceed the maximum size
+ * of the table.
+ * The full expiration check is for this purpose now.
+ */
+static void ip_vs_lblc_check_expire(unsigned long data)
+{
+ struct ip_vs_lblc_table *tbl;
+ unsigned long now = jiffies;
+ int goal;
+ int i, j;
+ struct ip_vs_lblc_entry *en, *nxt;
+
+ tbl = (struct ip_vs_lblc_table *)data;
+
+ if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) {
+ /* do full expiration check */
+ ip_vs_lblc_full_check(tbl);
+ tbl->counter = 1;
+ goto out;
+ }
+
+ if (atomic_read(&tbl->entries) <= tbl->max_size) {
+ tbl->counter++;
+ goto out;
+ }
+
+ goal = (atomic_read(&tbl->entries) - tbl->max_size)*4/3;
+ if (goal > tbl->max_size/2)
+ goal = tbl->max_size/2;
+
+ for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) {
+ j = (j + 1) & IP_VS_LBLC_TAB_MASK;
+
+ write_lock(&tbl->lock);
+ list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
+ if (time_before(now, en->lastuse + ENTRY_TIMEOUT))
+ continue;
+
+ ip_vs_lblc_free(en);
+ atomic_dec(&tbl->entries);
+ goal--;
+ }
+ write_unlock(&tbl->lock);
+ if (goal <= 0)
+ break;
+ }
+ tbl->rover = j;
+
+ out:
+ mod_timer(&tbl->periodic_timer, jiffies+CHECK_EXPIRE_INTERVAL);
+}
+
+
+static int ip_vs_lblc_init_svc(struct ip_vs_service *svc)
+{
+ int i;
+ struct ip_vs_lblc_table *tbl;
+
+ /*
+ * Allocate the ip_vs_lblc_table for this service
+ */
+ tbl = kmalloc(sizeof(struct ip_vs_lblc_table), GFP_ATOMIC);
+ if (tbl == NULL) {
+ IP_VS_ERR("ip_vs_lblc_init_svc(): no memory\n");
+ return -ENOMEM;
+ }
+ svc->sched_data = tbl;
+ IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) allocated for "
+ "current service\n",
+ sizeof(struct ip_vs_lblc_table));
+
+ /*
+ * Initialize the hash buckets
+ */
+ for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) {
+ INIT_LIST_HEAD(&tbl->bucket[i]);
+ }
+ rwlock_init(&tbl->lock);
+ tbl->max_size = IP_VS_LBLC_TAB_SIZE*16;
+ tbl->rover = 0;
+ tbl->counter = 1;
+
+ /*
+ * Hook periodic timer for garbage collection
+ */
+ init_timer(&tbl->periodic_timer);
+ tbl->periodic_timer.data = (unsigned long)tbl;
+ tbl->periodic_timer.function = ip_vs_lblc_check_expire;
+ tbl->periodic_timer.expires = jiffies+CHECK_EXPIRE_INTERVAL;
+ add_timer(&tbl->periodic_timer);
+
+ return 0;
+}
+
+
+static int ip_vs_lblc_done_svc(struct ip_vs_service *svc)
+{
+ struct ip_vs_lblc_table *tbl = svc->sched_data;
+
+ /* remove periodic timer */
+ del_timer_sync(&tbl->periodic_timer);
+
+ /* got to clean up table entries here */
+ ip_vs_lblc_flush(tbl);
+
+ /* release the table itself */
+ kfree(svc->sched_data);
+ IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) released\n",
+ sizeof(struct ip_vs_lblc_table));
+
+ return 0;
+}
+
+
+static int ip_vs_lblc_update_svc(struct ip_vs_service *svc)
+{
+ return 0;
+}
+
+
+static inline struct ip_vs_dest *
+__ip_vs_wlc_schedule(struct ip_vs_service *svc, struct iphdr *iph)
+{
+ struct ip_vs_dest *dest, *least;
+ int loh, doh;
+
+ /*
+ * We think the overhead of processing active connections is fifty
+ * times higher than that of inactive connections in average. (This
+ * fifty times might not be accurate, we will change it later.) We
+ * use the following formula to estimate the overhead:
+ * dest->activeconns*50 + dest->inactconns
+ * and the load:
+ * (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 connection.
+ */
+ list_for_each_entry(dest, &svc->destinations, n_list) {
+ if (dest->flags & IP_VS_DEST_F_OVERLOAD)
+ continue;
+ if (atomic_read(&dest->weight) > 0) {
+ least = dest;
+ loh = atomic_read(&least->activeconns) * 50
+ + atomic_read(&least->inactconns);
+ 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 = atomic_read(&dest->activeconns) * 50
+ + atomic_read(&dest->inactconns);
+ if (loh * atomic_read(&dest->weight) >
+ doh * atomic_read(&least->weight)) {
+ least = dest;
+ loh = doh;
+ }
+ }
+
+ IP_VS_DBG(6, "LBLC: server %d.%d.%d.%d:%d "
+ "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;
+}
+
+
+/*
+ * If this destination server is overloaded and there is a less loaded
+ * server, then return true.
+ */
+static inline int
+is_overloaded(struct ip_vs_dest *dest, struct ip_vs_service *svc)
+{
+ if (atomic_read(&dest->activeconns) > atomic_read(&dest->weight)) {
+ struct ip_vs_dest *d;
+
+ list_for_each_entry(d, &svc->destinations, n_list) {
+ if (atomic_read(&d->activeconns)*2
+ < atomic_read(&d->weight)) {
+ return 1;
+ }
+ }
+ }
+ return 0;
+}
+
+
+/*
+ * Locality-Based (weighted) Least-Connection scheduling
+ */
+static struct ip_vs_dest *
+ip_vs_lblc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
+{
+ struct ip_vs_dest *dest;
+ struct ip_vs_lblc_table *tbl;
+ struct ip_vs_lblc_entry *en;
+ struct iphdr *iph = skb->nh.iph;
+
+ IP_VS_DBG(6, "ip_vs_lblc_schedule(): Scheduling...\n");
+
+ tbl = (struct ip_vs_lblc_table *)svc->sched_data;
+ en = ip_vs_lblc_get(tbl, iph->daddr);
+ if (en == NULL) {
+ dest = __ip_vs_wlc_schedule(svc, iph);
+ if (dest == NULL) {
+ IP_VS_DBG(1, "no destination available\n");
+ return NULL;
+ }
+ en = ip_vs_lblc_new(iph->daddr, dest);
+ if (en == NULL) {
+ return NULL;
+ }
+ ip_vs_lblc_hash(tbl, en);
+ } else {
+ dest = en->dest;
+ if (!(dest->flags & IP_VS_DEST_F_AVAILABLE)
+ || atomic_read(&dest->weight) <= 0
+ || is_overloaded(dest, svc)) {
+ dest = __ip_vs_wlc_schedule(svc, iph);
+ if (dest == NULL) {
+ IP_VS_DBG(1, "no destination available\n");
+ return NULL;
+ }
+ atomic_dec(&en->dest->refcnt);
+ atomic_inc(&dest->refcnt);
+ en->dest = dest;
+ }
+ }
+ en->lastuse = jiffies;
+
+ IP_VS_DBG(6, "LBLC: destination IP address %u.%u.%u.%u "
+ "--> server %u.%u.%u.%u:%d\n",
+ NIPQUAD(en->addr),
+ NIPQUAD(dest->addr),
+ ntohs(dest->port));
+
+ return dest;
+}
+
+
+/*
+ * IPVS LBLC Scheduler structure
+ */
+static struct ip_vs_scheduler ip_vs_lblc_scheduler =
+{
+ .name = "lblc",
+ .refcnt = ATOMIC_INIT(0),
+ .module = THIS_MODULE,
+ .init_service = ip_vs_lblc_init_svc,
+ .done_service = ip_vs_lblc_done_svc,
+ .update_service = ip_vs_lblc_update_svc,
+ .schedule = ip_vs_lblc_schedule,
+};
+
+
+static int __init ip_vs_lblc_init(void)
+{
+ INIT_LIST_HEAD(&ip_vs_lblc_scheduler.n_list);
+ sysctl_header = register_sysctl_table(lblc_root_table, 0);
+ return register_ip_vs_scheduler(&ip_vs_lblc_scheduler);
+}
+
+
+static void __exit ip_vs_lblc_cleanup(void)
+{
+ unregister_sysctl_table(sysctl_header);
+ unregister_ip_vs_scheduler(&ip_vs_lblc_scheduler);
+}
+
+
+module_init(ip_vs_lblc_init);
+module_exit(ip_vs_lblc_cleanup);
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-18 02:53:31 +0000