patch-2.4.23 linux-2.4.23/net/ipv4/ipvs/ip_vs_lblcr.c
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- Lines: 885
- Date:
2003-11-28 10:26:21.000000000 -0800
- Orig file:
linux-2.4.22/net/ipv4/ipvs/ip_vs_lblcr.c
- Orig date:
1969-12-31 16:00:00.000000000 -0800
diff -urN linux-2.4.22/net/ipv4/ipvs/ip_vs_lblcr.c linux-2.4.23/net/ipv4/ipvs/ip_vs_lblcr.c
@@ -0,0 +1,884 @@
+/*
+ * IPVS: Locality-Based Least-Connection with Replication scheduler
+ *
+ * Version: $Id: ip_vs_lblcr.c,v 1.10 2002/03/25 12:44:35 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:
+ * Julian Anastasov : Added the missing (dest->weight>0)
+ * condition in the ip_vs_dest_set_max.
+ *
+ */
+
+/*
+ * The lblc/r algorithm is as follows (pseudo code):
+ *
+ * if serverSet[dest_ip] is null then
+ * n, serverSet[dest_ip] <- {weighted least-conn node};
+ * else
+ * n <- {least-conn (alive) node in serverSet[dest_ip]};
+ * if (n is null) OR
+ * (n.conns>n.weight AND
+ * there is a node m with m.conns<m.weight/2) then
+ * n <- {weighted least-conn node};
+ * add n to serverSet[dest_ip];
+ * if |serverSet[dest_ip]| > 1 AND
+ * now - serverSet[dest_ip].lastMod > T then
+ * m <- {most conn node in serverSet[dest_ip]};
+ * remove m from serverSet[dest_ip];
+ * if serverSet[dest_ip] changed then
+ * serverSet[dest_ip].lastMod <- now;
+ *
+ * return n;
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+
+/* for systcl */
+#include <linux/fs.h>
+#include <linux/sysctl.h>
+/* for proc_net_create/proc_net_remove */
+#include <linux/proc_fs.h>
+
+#include <net/ip_vs.h>
+
+
+/*
+ * It is for garbage collection of stale IPVS lblcr 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
+int sysctl_ip_vs_lblcr_expiration = 24*60*60*HZ;
+
+
+/*
+ * for IPVS lblcr entry hash table
+ */
+#ifndef CONFIG_IP_VS_LBLCR_TAB_BITS
+#define CONFIG_IP_VS_LBLCR_TAB_BITS 10
+#endif
+#define IP_VS_LBLCR_TAB_BITS CONFIG_IP_VS_LBLCR_TAB_BITS
+#define IP_VS_LBLCR_TAB_SIZE (1 << IP_VS_LBLCR_TAB_BITS)
+#define IP_VS_LBLCR_TAB_MASK (IP_VS_LBLCR_TAB_SIZE - 1)
+
+
+/*
+ * IPVS destination set structure and operations
+ */
+struct ip_vs_dest_list {
+ struct ip_vs_dest_list *next; /* list link */
+ struct ip_vs_dest *dest; /* destination server */
+};
+
+struct ip_vs_dest_set {
+ atomic_t size; /* set size */
+ unsigned long lastmod; /* last modified time */
+ struct ip_vs_dest_list *list; /* destination list */
+ rwlock_t lock; /* lock for this list */
+};
+
+
+static struct ip_vs_dest_list *
+ip_vs_dest_set_insert(struct ip_vs_dest_set *set, struct ip_vs_dest *dest)
+{
+ struct ip_vs_dest_list *e;
+
+ for (e=set->list; e!=NULL; e=e->next) {
+ if (e->dest == dest)
+ /* already existed */
+ return NULL;
+ }
+
+ e = kmalloc(sizeof(struct ip_vs_dest_list), GFP_ATOMIC);
+ if (e == NULL) {
+ IP_VS_ERR("ip_vs_dest_set_insert(): no memory\n");
+ return NULL;
+ }
+
+ atomic_inc(&dest->refcnt);
+ e->dest = dest;
+
+ /* link it to the list */
+ write_lock(&set->lock);
+ e->next = set->list;
+ set->list = e;
+ atomic_inc(&set->size);
+ write_unlock(&set->lock);
+
+ set->lastmod = jiffies;
+ return e;
+}
+
+static void
+ip_vs_dest_set_erase(struct ip_vs_dest_set *set, struct ip_vs_dest *dest)
+{
+ struct ip_vs_dest_list *e, **ep;
+
+ write_lock(&set->lock);
+ for (ep=&set->list, e=*ep; e!=NULL; e=*ep) {
+ if (e->dest == dest) {
+ /* HIT */
+ *ep = e->next;
+ atomic_dec(&set->size);
+ set->lastmod = jiffies;
+ atomic_dec(&e->dest->refcnt);
+ kfree(e);
+ break;
+ }
+ ep = &e->next;
+ }
+ write_unlock(&set->lock);
+}
+
+static void ip_vs_dest_set_eraseall(struct ip_vs_dest_set *set)
+{
+ struct ip_vs_dest_list *e, **ep;
+
+ write_lock(&set->lock);
+ for (ep=&set->list, e=*ep; e!=NULL; e=*ep) {
+ *ep = e->next;
+ /*
+ * We don't kfree dest because it is refered either
+ * by its service or by the trash dest list.
+ */
+ atomic_dec(&e->dest->refcnt);
+ kfree(e);
+ }
+ write_unlock(&set->lock);
+}
+
+/* get weighted least-connection node in the destination set */
+static inline struct ip_vs_dest *ip_vs_dest_set_min(struct ip_vs_dest_set *set)
+{
+ register struct ip_vs_dest_list *e;
+ struct ip_vs_dest *dest, *least;
+ int loh, doh;
+
+ if (set == NULL)
+ return NULL;
+
+ read_lock(&set->lock);
+ /* select the first destination server, whose weight > 0 */
+ for (e=set->list; e!=NULL; e=e->next) {
+ least = e->dest;
+ if ((atomic_read(&least->weight) > 0)
+ && (least->flags & IP_VS_DEST_F_AVAILABLE)) {
+ loh = atomic_read(&least->activeconns) * 50
+ + atomic_read(&least->inactconns);
+ goto nextstage;
+ }
+ }
+ read_unlock(&set->lock);
+ return NULL;
+
+ /* find the destination with the weighted least load */
+ nextstage:
+ for (e=e->next; e!=NULL; e=e->next) {
+ dest = e->dest;
+ doh = atomic_read(&dest->activeconns) * 50
+ + atomic_read(&dest->inactconns);
+ if ((loh * atomic_read(&dest->weight) >
+ doh * atomic_read(&least->weight))
+ && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
+ least = dest;
+ loh = doh;
+ }
+ }
+ read_unlock(&set->lock);
+
+ IP_VS_DBG(6, "ip_vs_dest_set_min: 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;
+}
+
+
+/* get weighted most-connection node in the destination set */
+static inline struct ip_vs_dest *ip_vs_dest_set_max(struct ip_vs_dest_set *set)
+{
+ register struct ip_vs_dest_list *e;
+ struct ip_vs_dest *dest, *most;
+ int moh, doh;
+
+ if (set == NULL)
+ return NULL;
+
+ read_lock(&set->lock);
+ /* select the first destination server, whose weight > 0 */
+ for (e=set->list; e!=NULL; e=e->next) {
+ most = e->dest;
+ if (atomic_read(&most->weight) > 0) {
+ moh = atomic_read(&most->activeconns) * 50
+ + atomic_read(&most->inactconns);
+ goto nextstage;
+ }
+ }
+ read_unlock(&set->lock);
+ return NULL;
+
+ /* find the destination with the weighted most load */
+ nextstage:
+ for (e=e->next; e!=NULL; e=e->next) {
+ dest = e->dest;
+ doh = atomic_read(&dest->activeconns) * 50
+ + atomic_read(&dest->inactconns);
+ /* moh/mw < doh/dw ==> moh*dw < doh*mw, where mw,dw>0 */
+ if ((moh * atomic_read(&dest->weight) <
+ doh * atomic_read(&most->weight))
+ && (atomic_read(&dest->weight) > 0)) {
+ most = dest;
+ moh = doh;
+ }
+ }
+ read_unlock(&set->lock);
+
+ IP_VS_DBG(6, "ip_vs_dest_set_max: server %d.%d.%d.%d:%d "
+ "activeconns %d refcnt %d weight %d overhead %d\n",
+ NIPQUAD(most->addr), ntohs(most->port),
+ atomic_read(&most->activeconns),
+ atomic_read(&most->refcnt),
+ atomic_read(&most->weight), moh);
+ return most;
+}
+
+
+/*
+ * IPVS lblcr entry represents an association between destination
+ * IP address and its destination server set
+ */
+struct ip_vs_lblcr_entry {
+ struct list_head list;
+ __u32 addr; /* destination IP address */
+ struct ip_vs_dest_set set; /* destination server set */
+ unsigned long lastuse; /* last used time */
+};
+
+
+/*
+ * IPVS lblcr hash table
+ */
+struct ip_vs_lblcr_table {
+ rwlock_t lock; /* lock for this table */
+ struct list_head bucket[IP_VS_LBLCR_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 LBLCR sysctl table
+ */
+struct ip_vs_lblcr_sysctl_table {
+ struct ctl_table_header *sysctl_header;
+ ctl_table vs_vars[2];
+ ctl_table vs_dir[2];
+ ctl_table ipv4_dir[2];
+ ctl_table root_dir[2];
+};
+
+
+static struct ip_vs_lblcr_sysctl_table lblcr_sysctl_table = {
+ NULL,
+ {{NET_IPV4_VS_LBLCR_EXPIRE, "lblcr_expiration",
+ &sysctl_ip_vs_lblcr_expiration,
+ sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
+ {0}},
+ {{NET_IPV4_VS, "vs", NULL, 0, 0555, lblcr_sysctl_table.vs_vars},
+ {0}},
+ {{NET_IPV4, "ipv4", NULL, 0, 0555, lblcr_sysctl_table.vs_dir},
+ {0}},
+ {{CTL_NET, "net", NULL, 0, 0555, lblcr_sysctl_table.ipv4_dir},
+ {0}}
+};
+
+
+/*
+ * new/free a ip_vs_lblcr_entry, which is a mapping of a destination
+ * IP address to a server.
+ */
+static inline struct ip_vs_lblcr_entry *ip_vs_lblcr_new(__u32 daddr)
+{
+ struct ip_vs_lblcr_entry *en;
+
+ en = kmalloc(sizeof(struct ip_vs_lblcr_entry), GFP_ATOMIC);
+ if (en == NULL) {
+ IP_VS_ERR("ip_vs_lblcr_new(): no memory\n");
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&en->list);
+ en->addr = daddr;
+
+ /* initilize its dest set */
+ atomic_set(&(en->set.size), 0);
+ en->set.list = NULL;
+ en->set.lock = RW_LOCK_UNLOCKED;
+
+ return en;
+}
+
+
+static inline void ip_vs_lblcr_free(struct ip_vs_lblcr_entry *en)
+{
+ list_del(&en->list);
+ ip_vs_dest_set_eraseall(&en->set);
+ kfree(en);
+}
+
+
+/*
+ * Returns hash value for IPVS LBLCR entry
+ */
+static inline unsigned ip_vs_lblcr_hashkey(__u32 addr)
+{
+ return (ntohl(addr)*2654435761UL) & IP_VS_LBLCR_TAB_MASK;
+}
+
+
+/*
+ * Hash an entry in the ip_vs_lblcr_table.
+ * returns bool success.
+ */
+static int
+ip_vs_lblcr_hash(struct ip_vs_lblcr_table *tbl, struct ip_vs_lblcr_entry *en)
+{
+ unsigned hash;
+
+ if (!list_empty(&en->list)) {
+ IP_VS_ERR("ip_vs_lblcr_hash(): request for already hashed, "
+ "called from %p\n", __builtin_return_address(0));
+ return 0;
+ }
+
+ /*
+ * Hash by destination IP address
+ */
+ hash = ip_vs_lblcr_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_lblcr_entry from ip_vs_lblcr_table.
+ * returns bool success.
+ */
+static int ip_vs_lblcr_unhash(struct ip_vs_lblcr_table *tbl,
+ struct ip_vs_lblcr_entry *en)
+{
+ if (list_empty(&en->list)) {
+ IP_VS_ERR("ip_vs_lblcr_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_lblcr_entry associated with supplied parameters.
+ */
+static inline struct ip_vs_lblcr_entry *
+ip_vs_lblcr_get(struct ip_vs_lblcr_table *tbl, __u32 addr)
+{
+ unsigned hash;
+ struct ip_vs_lblcr_entry *en;
+ struct list_head *l,*e;
+
+ hash = ip_vs_lblcr_hashkey(addr);
+ l = &tbl->bucket[hash];
+
+ read_lock(&tbl->lock);
+
+ for (e=l->next; e!=l; e=e->next) {
+ en = list_entry(e, struct ip_vs_lblcr_entry, 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_lblcr_flush(struct ip_vs_lblcr_table *tbl)
+{
+ int i;
+ struct list_head *l;
+ struct ip_vs_lblcr_entry *en;
+
+ for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
+ write_lock(&tbl->lock);
+ for (l=&tbl->bucket[i]; l->next!=l; ) {
+ en = list_entry(l->next,
+ struct ip_vs_lblcr_entry, list);
+ ip_vs_lblcr_free(en);
+ atomic_dec(&tbl->entries);
+ }
+ write_unlock(&tbl->lock);
+ }
+}
+
+
+static inline void ip_vs_lblcr_full_check(struct ip_vs_lblcr_table *tbl)
+{
+ unsigned long now = jiffies;
+ int i, j;
+ struct list_head *l, *e;
+ struct ip_vs_lblcr_entry *en;
+
+ for (i=0, j=tbl->rover; i<IP_VS_LBLCR_TAB_SIZE; i++) {
+ j = (j + 1) & IP_VS_LBLCR_TAB_MASK;
+ e = l = &tbl->bucket[j];
+ write_lock(&tbl->lock);
+ while (e->next != l) {
+ en = list_entry(e->next,
+ struct ip_vs_lblcr_entry, list);
+ if ((now - en->lastuse) <
+ sysctl_ip_vs_lblcr_expiration) {
+ e = e->next;
+ continue;
+ }
+ ip_vs_lblcr_free(en);
+ atomic_dec(&tbl->entries);
+ }
+ write_unlock(&tbl->lock);
+ }
+ tbl->rover = j;
+}
+
+
+/*
+ * Periodical timer handler for IPVS lblcr 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_lblcr_check_expire(unsigned long data)
+{
+ struct ip_vs_lblcr_table *tbl;
+ unsigned long now = jiffies;
+ int goal;
+ int i, j;
+ struct list_head *l, *e;
+ struct ip_vs_lblcr_entry *en;
+
+ tbl = (struct ip_vs_lblcr_table *)data;
+
+ if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) {
+ /* do full expiration check */
+ ip_vs_lblcr_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_LBLCR_TAB_SIZE; i++) {
+ j = (j + 1) & IP_VS_LBLCR_TAB_MASK;
+ e = l = &tbl->bucket[j];
+ write_lock(&tbl->lock);
+ while (e->next != l) {
+ en = list_entry(e->next,
+ struct ip_vs_lblcr_entry, list);
+ if ((now - en->lastuse) < ENTRY_TIMEOUT) {
+ e = e->next;
+ continue;
+ }
+ ip_vs_lblcr_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);
+}
+
+
+#ifdef CONFIG_IP_VS_LBLCR_DEBUG
+static struct ip_vs_lblcr_table *lblcr_table_list;
+
+/*
+ * /proc/net/ip_vs_lblcr to display the mappings of
+ * destination IP address <==> its serverSet
+ */
+static int
+ip_vs_lblcr_getinfo(char *buffer, char **start, off_t offset, int length)
+{
+ off_t pos=0, begin;
+ int len=0, size;
+ struct ip_vs_lblcr_table *tbl;
+ unsigned long now = jiffies;
+ int i;
+ struct list_head *l, *e;
+ struct ip_vs_lblcr_entry *en;
+
+ tbl = lblcr_table_list;
+
+ size = sprintf(buffer, "LastTime Dest IP address Server set\n");
+ pos += size;
+ len += size;
+
+ for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
+ l = &tbl->bucket[i];
+ read_lock_bh(&tbl->lock);
+ for (e=l->next; e!=l; e=e->next) {
+ char tbuf[16];
+ struct ip_vs_dest_list *d;
+
+ en = list_entry(e, struct ip_vs_lblcr_entry, list);
+ sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(en->addr));
+ size = sprintf(buffer+len, "%8lu %-16s ",
+ now-en->lastuse, tbuf);
+
+ read_lock(&en->set.lock);
+ for (d=en->set.list; d!=NULL; d=d->next) {
+ size += sprintf(buffer+len+size,
+ "%u.%u.%u.%u ",
+ NIPQUAD(d->dest->addr));
+ }
+ read_unlock(&en->set.lock);
+ size += sprintf(buffer+len+size, "\n");
+ len += size;
+ pos += size;
+ if (pos <= offset)
+ len=0;
+ if (pos >= offset+length) {
+ read_unlock_bh(&tbl->lock);
+ goto done;
+ }
+ }
+ read_unlock_bh(&tbl->lock);
+ }
+
+ done:
+ begin = len - (pos - offset);
+ *start = buffer + begin;
+ len -= begin;
+ if(len>length)
+ len = length;
+ return len;
+}
+#endif
+
+
+static int ip_vs_lblcr_init_svc(struct ip_vs_service *svc)
+{
+ int i;
+ struct ip_vs_lblcr_table *tbl;
+
+ /*
+ * Allocate the ip_vs_lblcr_table for this service
+ */
+ tbl = kmalloc(sizeof(struct ip_vs_lblcr_table), GFP_ATOMIC);
+ if (tbl == NULL) {
+ IP_VS_ERR("ip_vs_lblcr_init_svc(): no memory\n");
+ return -ENOMEM;
+ }
+ svc->sched_data = tbl;
+ IP_VS_DBG(6, "LBLCR hash table (memory=%dbytes) allocated for "
+ "current service\n",
+ sizeof(struct ip_vs_lblcr_table));
+
+ /*
+ * Initialize the hash buckets
+ */
+ for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
+ INIT_LIST_HEAD(&tbl->bucket[i]);
+ }
+ tbl->lock = RW_LOCK_UNLOCKED;
+ tbl->max_size = IP_VS_LBLCR_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_lblcr_check_expire;
+ tbl->periodic_timer.expires = jiffies+CHECK_EXPIRE_INTERVAL;
+ add_timer(&tbl->periodic_timer);
+
+#ifdef CONFIG_IP_VS_LBLCR_DEBUG
+ lblcr_table_list = tbl;
+#endif
+ return 0;
+}
+
+
+static int ip_vs_lblcr_done_svc(struct ip_vs_service *svc)
+{
+ struct ip_vs_lblcr_table *tbl = svc->sched_data;
+
+ /* remove periodic timer */
+ del_timer_sync(&tbl->periodic_timer);
+
+ /* got to clean up table entries here */
+ ip_vs_lblcr_flush(tbl);
+
+ /* release the table itself */
+ kfree(svc->sched_data);
+ IP_VS_DBG(6, "LBLCR hash table (memory=%dbytes) released\n",
+ sizeof(struct ip_vs_lblcr_table));
+
+ return 0;
+}
+
+
+static int ip_vs_lblcr_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)
+{
+ register struct list_head *l, *e;
+ 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.
+ */
+
+ l = &svc->destinations;
+ for (e=l->next; e!=l; e=e->next) {
+ least = list_entry(e, struct ip_vs_dest, n_list);
+ if (atomic_read(&least->weight) > 0) {
+ loh = atomic_read(&least->activeconns) * 50
+ + atomic_read(&least->inactconns);
+ goto nextstage;
+ }
+ }
+ return NULL;
+
+ /*
+ * Find the destination with the least load.
+ */
+ nextstage:
+ for (e=e->next; e!=l; e=e->next) {
+ dest = list_entry(e, struct ip_vs_dest, n_list);
+ 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, "LBLCR: 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)) {
+ register struct list_head *l, *e;
+ struct ip_vs_dest *d;
+
+ l = &svc->destinations;
+ for (e=l->next; e!=l; e=e->next) {
+ d = list_entry(e, struct ip_vs_dest, 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_lblcr_schedule(struct ip_vs_service *svc, struct iphdr *iph)
+{
+ struct ip_vs_dest *dest;
+ struct ip_vs_lblcr_table *tbl;
+ struct ip_vs_lblcr_entry *en;
+
+ IP_VS_DBG(6, "ip_vs_lblcr_schedule(): Scheduling...\n");
+
+ tbl = (struct ip_vs_lblcr_table *)svc->sched_data;
+ en = ip_vs_lblcr_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_lblcr_new(iph->daddr);
+ if (en == NULL) {
+ return NULL;
+ }
+ ip_vs_dest_set_insert(&en->set, dest);
+ ip_vs_lblcr_hash(tbl, en);
+ } else {
+ dest = ip_vs_dest_set_min(&en->set);
+ if (!dest || is_overloaded(dest, svc)) {
+ dest = __ip_vs_wlc_schedule(svc, iph);
+ if (dest == NULL) {
+ IP_VS_DBG(1, "no destination available\n");
+ return NULL;
+ }
+ ip_vs_dest_set_insert(&en->set, dest);
+ }
+ if (atomic_read(&en->set.size) > 1 &&
+ jiffies-en->set.lastmod > sysctl_ip_vs_lblcr_expiration) {
+ struct ip_vs_dest *m;
+ m = ip_vs_dest_set_max(&en->set);
+ if (m)
+ ip_vs_dest_set_erase(&en->set, m);
+ }
+ }
+ en->lastuse = jiffies;
+
+ IP_VS_DBG(6, "LBLCR: 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 LBLCR Scheduler structure
+ */
+static struct ip_vs_scheduler ip_vs_lblcr_scheduler =
+{
+ {0}, /* n_list */
+ "lblcr", /* name */
+ ATOMIC_INIT(0), /* refcnt */
+ THIS_MODULE, /* this module */
+ ip_vs_lblcr_init_svc, /* service initializer */
+ ip_vs_lblcr_done_svc, /* service done */
+ ip_vs_lblcr_update_svc, /* service updater */
+ ip_vs_lblcr_schedule, /* select a server from the destination list */
+};
+
+
+static int __init ip_vs_lblcr_init(void)
+{
+ INIT_LIST_HEAD(&ip_vs_lblcr_scheduler.n_list);
+ lblcr_sysctl_table.sysctl_header =
+ register_sysctl_table(lblcr_sysctl_table.root_dir, 0);
+#ifdef CONFIG_IP_VS_LBLCR_DEBUG
+ proc_net_create("ip_vs_lblcr", 0, ip_vs_lblcr_getinfo);
+#endif
+ return register_ip_vs_scheduler(&ip_vs_lblcr_scheduler);
+}
+
+
+static void __exit ip_vs_lblcr_cleanup(void)
+{
+#ifdef CONFIG_IP_VS_LBLCR_DEBUG
+ proc_net_remove("ip_vs_lblcr");
+#endif
+ unregister_sysctl_table(lblcr_sysctl_table.sysctl_header);
+ unregister_ip_vs_scheduler(&ip_vs_lblcr_scheduler);
+}
+
+
+module_init(ip_vs_lblcr_init);
+module_exit(ip_vs_lblcr_cleanup);
+MODULE_LICENSE("GPL");
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TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)