Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

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 000000000000..c035838b780a
--- /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");