net/ipv4/ipvs/ip_vs_lblcr.c

   1 /*
   2  * IPVS:        Locality-Based Least-Connection with Replication scheduler
   3  *
   4  * Version:     $Id: ip_vs_lblcr.c,v 1.11 2002/09/15 08:14:08 wensong Exp $
   5  *
   6  * Authors:     Wensong Zhang <wensong@gnuchina.org>
   7  *
   8  *              This program is free software; you can redistribute it and/or
   9  *              modify it under the terms of the GNU General Public License
  10  *              as published by the Free Software Foundation; either version
  11  *              2 of the License, or (at your option) any later version.
  12  *
  13  * Changes:
  14  *     Julian Anastasov        :    Added the missing (dest->weight>0)
  15  *                                  condition in the ip_vs_dest_set_max.
  16  *
  17  */
  18
  19 /*
  20  * The lblc/r algorithm is as follows (pseudo code):
  21  *
  22  *       if serverSet[dest_ip] is null then
  23  *               n, serverSet[dest_ip] <- {weighted least-conn node};
  24  *       else
  25  *               n <- {least-conn (alive) node in serverSet[dest_ip]};
  26  *               if (n is null) OR
  27  *                  (n.conns>n.weight AND
  28  *                   there is a node m with m.conns<m.weight/2) then
  29  *                   n <- {weighted least-conn node};
  30  *                   add n to serverSet[dest_ip];
  31  *               if |serverSet[dest_ip]| > 1 AND
  32  *                   now - serverSet[dest_ip].lastMod > T then
  33  *                   m <- {most conn node in serverSet[dest_ip]};
  34  *                   remove m from serverSet[dest_ip];
  35  *       if serverSet[dest_ip] changed then
  36  *               serverSet[dest_ip].lastMod <- now;
  37  *
  38  *       return n;
  39  *
  40  */
  41
  42 #include <linux/module.h>
  43 #include <linux/kernel.h>
  44
  45 /* for sysctl */
  46 #include <linux/fs.h>
  47 #include <linux/sysctl.h>
  48 /* for proc_net_create/proc_net_remove */
  49 #include <linux/proc_fs.h>
  50
  51 #include <net/ip_vs.h>
  52
  53
  54 /*
  55  *    It is for garbage collection of stale IPVS lblcr entries,
  56  *    when the table is full.
  57  */
  58 #define CHECK_EXPIRE_INTERVAL   (60*HZ)
  59 #define ENTRY_TIMEOUT           (6*60*HZ)
  60
  61 /*
  62  *    It is for full expiration check.
  63  *    When there is no partial expiration check (garbage collection)
  64  *    in a half hour, do a full expiration check to collect stale
  65  *    entries that haven't been touched for a day.
  66  */
  67 #define COUNT_FOR_FULL_EXPIRATION   30
  68 static int sysctl_ip_vs_lblcr_expiration = 24*60*60*HZ;
  69
  70
  71 /*
  72  *     for IPVS lblcr entry hash table
  73  */
  74 #ifndef CONFIG_IP_VS_LBLCR_TAB_BITS
  75 #define CONFIG_IP_VS_LBLCR_TAB_BITS      10
  76 #endif
  77 #define IP_VS_LBLCR_TAB_BITS     CONFIG_IP_VS_LBLCR_TAB_BITS
  78 #define IP_VS_LBLCR_TAB_SIZE     (1 << IP_VS_LBLCR_TAB_BITS)
  79 #define IP_VS_LBLCR_TAB_MASK     (IP_VS_LBLCR_TAB_SIZE - 1)
  80
  81
  82 /*
  83  *      IPVS destination set structure and operations
  84  */
  85 struct ip_vs_dest_list {
  86         struct ip_vs_dest_list  *next;          /* list link */
  87         struct ip_vs_dest       *dest;          /* destination server */
  88 };
  89
  90 struct ip_vs_dest_set {
  91         atomic_t                size;           /* set size */
  92         unsigned long           lastmod;        /* last modified time */
  93         struct ip_vs_dest_list  *list;          /* destination list */
  94         rwlock_t                lock;           /* lock for this list */
  95 };
  96
  97
  98 static struct ip_vs_dest_list *
  99 ip_vs_dest_set_insert(struct ip_vs_dest_set *set, struct ip_vs_dest *dest)
 100 {
 101         struct ip_vs_dest_list *e;
 102
 103         for (e=set->list; e!=NULL; e=e->next) {
 104                 if (e->dest == dest)
 105                         /* already existed */
 106                         return NULL;
 107         }
 108
 109         e = kmalloc(sizeof(struct ip_vs_dest_list), GFP_ATOMIC);
 110         if (e == NULL) {
 111                 IP_VS_ERR("ip_vs_dest_set_insert(): no memory\n");
 112                 return NULL;
 113         }
 114
 115         atomic_inc(&dest->refcnt);
 116         e->dest = dest;
 117
 118         /* link it to the list */
 119         write_lock(&set->lock);
 120         e->next = set->list;
 121         set->list = e;
 122         atomic_inc(&set->size);
 123         write_unlock(&set->lock);
 124
 125         set->lastmod = jiffies;
 126         return e;
 127 }
 128
 129 static void
 130 ip_vs_dest_set_erase(struct ip_vs_dest_set *set, struct ip_vs_dest *dest)
 131 {
 132         struct ip_vs_dest_list *e, **ep;
 133
 134         write_lock(&set->lock);
 135         for (ep=&set->list, e=*ep; e!=NULL; e=*ep) {
 136                 if (e->dest == dest) {
 137                         /* HIT */
 138                         *ep = e->next;
 139                         atomic_dec(&set->size);
 140                         set->lastmod = jiffies;
 141                         atomic_dec(&e->dest->refcnt);
 142                         kfree(e);
 143                         break;
 144                 }
 145                 ep = &e->next;
 146         }
 147         write_unlock(&set->lock);
 148 }
 149
 150 static void ip_vs_dest_set_eraseall(struct ip_vs_dest_set *set)
 151 {
 152         struct ip_vs_dest_list *e, **ep;
 153
 154         write_lock(&set->lock);
 155         for (ep=&set->list, e=*ep; e!=NULL; e=*ep) {
 156                 *ep = e->next;
 157                 /*
 158                  * We don't kfree dest because it is refered either
 159                  * by its service or by the trash dest list.
 160                  */
 161                 atomic_dec(&e->dest->refcnt);
 162                 kfree(e);
 163         }
 164         write_unlock(&set->lock);
 165 }
 166
 167 /* get weighted least-connection node in the destination set */
 168 static inline struct ip_vs_dest *ip_vs_dest_set_min(struct ip_vs_dest_set *set)
 169 {
 170         register struct ip_vs_dest_list *e;
 171         struct ip_vs_dest *dest, *least;
 172         int loh, doh;
 173
 174         if (set == NULL)
 175                 return NULL;
 176
 177         read_lock(&set->lock);
 178         /* select the first destination server, whose weight > 0 */
 179         for (e=set->list; e!=NULL; e=e->next) {
 180                 least = e->dest;
 181                 if (least->flags & IP_VS_DEST_F_OVERLOAD)
 182                         continue;
 183
 184                 if ((atomic_read(&least->weight) > 0)
 185                     && (least->flags & IP_VS_DEST_F_AVAILABLE)) {
 186                         loh = atomic_read(&least->activeconns) * 50
 187                                 + atomic_read(&least->inactconns);
 188                         goto nextstage;
 189                 }
 190         }
 191         read_unlock(&set->lock);
 192         return NULL;
 193
 194         /* find the destination with the weighted least load */
 195   nextstage:
 196         for (e=e->next; e!=NULL; e=e->next) {
 197                 dest = e->dest;
 198                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 199                         continue;
 200
 201                 doh = atomic_read(&dest->activeconns) * 50
 202                         + atomic_read(&dest->inactconns);
 203                 if ((loh * atomic_read(&dest->weight) >
 204                      doh * atomic_read(&least->weight))
 205                     && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
 206                         least = dest;
 207                         loh = doh;
 208                 }
 209         }
 210         read_unlock(&set->lock);
 211
 212         IP_VS_DBG(6, "ip_vs_dest_set_min: server %d.%d.%d.%d:%d "
 213                   "activeconns %d refcnt %d weight %d overhead %d\n",
 214                   NIPQUAD(least->addr), ntohs(least->port),
 215                   atomic_read(&least->activeconns),
 216                   atomic_read(&least->refcnt),
 217                   atomic_read(&least->weight), loh);
 218         return least;
 219 }
 220
 221
 222 /* get weighted most-connection node in the destination set */
 223 static inline struct ip_vs_dest *ip_vs_dest_set_max(struct ip_vs_dest_set *set)
 224 {
 225         register struct ip_vs_dest_list *e;
 226         struct ip_vs_dest *dest, *most;
 227         int moh, doh;
 228
 229         if (set == NULL)
 230                 return NULL;
 231
 232         read_lock(&set->lock);
 233         /* select the first destination server, whose weight > 0 */
 234         for (e=set->list; e!=NULL; e=e->next) {
 235                 most = e->dest;
 236                 if (atomic_read(&most->weight) > 0) {
 237                         moh = atomic_read(&most->activeconns) * 50
 238                                 + atomic_read(&most->inactconns);
 239                         goto nextstage;
 240                 }
 241         }
 242         read_unlock(&set->lock);
 243         return NULL;
 244
 245         /* find the destination with the weighted most load */
 246   nextstage:
 247         for (e=e->next; e!=NULL; e=e->next) {
 248                 dest = e->dest;
 249                 doh = atomic_read(&dest->activeconns) * 50
 250                         + atomic_read(&dest->inactconns);
 251                 /* moh/mw < doh/dw ==> moh*dw < doh*mw, where mw,dw>0 */
 252                 if ((moh * atomic_read(&dest->weight) <
 253                      doh * atomic_read(&most->weight))
 254                     && (atomic_read(&dest->weight) > 0)) {
 255                         most = dest;
 256                         moh = doh;
 257                 }
 258         }
 259         read_unlock(&set->lock);
 260
 261         IP_VS_DBG(6, "ip_vs_dest_set_max: server %d.%d.%d.%d:%d "
 262                   "activeconns %d refcnt %d weight %d overhead %d\n",
 263                   NIPQUAD(most->addr), ntohs(most->port),
 264                   atomic_read(&most->activeconns),
 265                   atomic_read(&most->refcnt),
 266                   atomic_read(&most->weight), moh);
 267         return most;
 268 }
 269
 270
 271 /*
 272  *      IPVS lblcr entry represents an association between destination
 273  *      IP address and its destination server set
 274  */
 275 struct ip_vs_lblcr_entry {
 276         struct list_head        list;
 277         __u32                   addr;           /* destination IP address */
 278         struct ip_vs_dest_set   set;            /* destination server set */
 279         unsigned long           lastuse;        /* last used time */
 280 };
 281
 282
 283 /*
 284  *      IPVS lblcr hash table
 285  */
 286 struct ip_vs_lblcr_table {
 287         rwlock_t                lock;           /* lock for this table */
 288         struct list_head        bucket[IP_VS_LBLCR_TAB_SIZE];  /* hash bucket */
 289         atomic_t                entries;        /* number of entries */
 290         int                     max_size;       /* maximum size of entries */
 291         struct timer_list       periodic_timer; /* collect stale entries */
 292         int                     rover;          /* rover for expire check */
 293         int                     counter;        /* counter for no expire */
 294 };
 295
 296
 297 /*
 298  *      IPVS LBLCR sysctl table
 299  */
 300
 301 static ctl_table vs_vars_table[] = {
 302         {
 303                 .ctl_name       = NET_IPV4_VS_LBLCR_EXPIRE,
 304                 .procname       = "lblcr_expiration",
 305                 .data           = &sysctl_ip_vs_lblcr_expiration,
 306                 .maxlen         = sizeof(int),
 307                 .mode           = 0644,
 308                 .proc_handler   = &proc_dointvec_jiffies,
 309         },
 310         { .ctl_name = 0 }
 311 };
 312
 313 static ctl_table vs_table[] = {
 314         {
 315                 .ctl_name       = NET_IPV4_VS,
 316                 .procname       = "vs",
 317                 .mode           = 0555,
 318                 .child          = vs_vars_table
 319         },
 320         { .ctl_name = 0 }
 321 };
 322
 323 static ctl_table ipvs_ipv4_table[] = {
 324         {
 325                 .ctl_name       = NET_IPV4,
 326                 .procname       = "ipv4",
 327                 .mode           = 0555,
 328                 .child          = vs_table
 329         },
 330         { .ctl_name = 0 }
 331 };
 332
 333 static ctl_table lblcr_root_table[] = {
 334         {
 335                 .ctl_name       = CTL_NET,
 336                 .procname       = "net",
 337                 .mode           = 0555,
 338                 .child          = ipvs_ipv4_table
 339         },
 340         { .ctl_name = 0 }
 341 };
 342
 343 static struct ctl_table_header * sysctl_header;
 344
 345 /*
 346  *      new/free a ip_vs_lblcr_entry, which is a mapping of a destination
 347  *      IP address to a server.
 348  */
 349 static inline struct ip_vs_lblcr_entry *ip_vs_lblcr_new(__u32 daddr)
 350 {
 351         struct ip_vs_lblcr_entry *en;
 352
 353         en = kmalloc(sizeof(struct ip_vs_lblcr_entry), GFP_ATOMIC);
 354         if (en == NULL) {
 355                 IP_VS_ERR("ip_vs_lblcr_new(): no memory\n");
 356                 return NULL;
 357         }
 358
 359         INIT_LIST_HEAD(&en->list);
 360         en->addr = daddr;
 361
 362         /* initilize its dest set */
 363         atomic_set(&(en->set.size), 0);
 364         en->set.list = NULL;
 365         rwlock_init(&en->set.lock);
 366
 367         return en;
 368 }
 369
 370
 371 static inline void ip_vs_lblcr_free(struct ip_vs_lblcr_entry *en)
 372 {
 373         list_del(&en->list);
 374         ip_vs_dest_set_eraseall(&en->set);
 375         kfree(en);
 376 }
 377
 378
 379 /*
 380  *      Returns hash value for IPVS LBLCR entry
 381  */
 382 static inline unsigned ip_vs_lblcr_hashkey(__u32 addr)
 383 {
 384         return (ntohl(addr)*2654435761UL) & IP_VS_LBLCR_TAB_MASK;
 385 }
 386
 387
 388 /*
 389  *      Hash an entry in the ip_vs_lblcr_table.
 390  *      returns bool success.
 391  */
 392 static int
 393 ip_vs_lblcr_hash(struct ip_vs_lblcr_table *tbl, struct ip_vs_lblcr_entry *en)
 394 {
 395         unsigned hash;
 396
 397         if (!list_empty(&en->list)) {
 398                 IP_VS_ERR("ip_vs_lblcr_hash(): request for already hashed, "
 399                           "called from %p\n", __builtin_return_address(0));
 400                 return 0;
 401         }
 402
 403         /*
 404          *      Hash by destination IP address
 405          */
 406         hash = ip_vs_lblcr_hashkey(en->addr);
 407
 408         write_lock(&tbl->lock);
 409         list_add(&en->list, &tbl->bucket[hash]);
 410         atomic_inc(&tbl->entries);
 411         write_unlock(&tbl->lock);
 412
 413         return 1;
 414 }
 415
 416
 417 /*
 418  *  Get ip_vs_lblcr_entry associated with supplied parameters.
 419  */
 420 static inline struct ip_vs_lblcr_entry *
 421 ip_vs_lblcr_get(struct ip_vs_lblcr_table *tbl, __u32 addr)
 422 {
 423         unsigned hash;
 424         struct ip_vs_lblcr_entry *en;
 425
 426         hash = ip_vs_lblcr_hashkey(addr);
 427
 428         read_lock(&tbl->lock);
 429
 430         list_for_each_entry(en, &tbl->bucket[hash], list) {
 431                 if (en->addr == addr) {
 432                         /* HIT */
 433                         read_unlock(&tbl->lock);
 434                         return en;
 435                 }
 436         }
 437
 438         read_unlock(&tbl->lock);
 439
 440         return NULL;
 441 }
 442
 443
 444 /*
 445  *      Flush all the entries of the specified table.
 446  */
 447 static void ip_vs_lblcr_flush(struct ip_vs_lblcr_table *tbl)
 448 {
 449         int i;
 450         struct ip_vs_lblcr_entry *en, *nxt;
 451
 452         for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
 453                 write_lock(&tbl->lock);
 454                 list_for_each_entry_safe(en, nxt, &tbl->bucket[i], list) {
 455                         ip_vs_lblcr_free(en);
 456                         atomic_dec(&tbl->entries);
 457                 }
 458                 write_unlock(&tbl->lock);
 459         }
 460 }
 461
 462
 463 static inline void ip_vs_lblcr_full_check(struct ip_vs_lblcr_table *tbl)
 464 {
 465         unsigned long now = jiffies;
 466         int i, j;
 467         struct ip_vs_lblcr_entry *en, *nxt;
 468
 469         for (i=0, j=tbl->rover; i<IP_VS_LBLCR_TAB_SIZE; i++) {
 470                 j = (j + 1) & IP_VS_LBLCR_TAB_MASK;
 471
 472                 write_lock(&tbl->lock);
 473                 list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
 474                         if (time_after(en->lastuse+sysctl_ip_vs_lblcr_expiration,
 475                                        now))
 476                                 continue;
 477
 478                         ip_vs_lblcr_free(en);
 479                         atomic_dec(&tbl->entries);
 480                 }
 481                 write_unlock(&tbl->lock);
 482         }
 483         tbl->rover = j;
 484 }
 485
 486
 487 /*
 488  *      Periodical timer handler for IPVS lblcr table
 489  *      It is used to collect stale entries when the number of entries
 490  *      exceeds the maximum size of the table.
 491  *
 492  *      Fixme: we probably need more complicated algorithm to collect
 493  *             entries that have not been used for a long time even
 494  *             if the number of entries doesn't exceed the maximum size
 495  *             of the table.
 496  *      The full expiration check is for this purpose now.
 497  */
 498 static void ip_vs_lblcr_check_expire(unsigned long data)
 499 {
 500         struct ip_vs_lblcr_table *tbl;
 501         unsigned long now = jiffies;
 502         int goal;
 503         int i, j;
 504         struct ip_vs_lblcr_entry *en, *nxt;
 505
 506         tbl = (struct ip_vs_lblcr_table *)data;
 507
 508         if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) {
 509                 /* do full expiration check */
 510                 ip_vs_lblcr_full_check(tbl);
 511                 tbl->counter = 1;
 512                 goto out;
 513         }
 514
 515         if (atomic_read(&tbl->entries) <= tbl->max_size) {
 516                 tbl->counter++;
 517                 goto out;
 518         }
 519
 520         goal = (atomic_read(&tbl->entries) - tbl->max_size)*4/3;
 521         if (goal > tbl->max_size/2)
 522                 goal = tbl->max_size/2;
 523
 524         for (i=0, j=tbl->rover; i<IP_VS_LBLCR_TAB_SIZE; i++) {
 525                 j = (j + 1) & IP_VS_LBLCR_TAB_MASK;
 526
 527                 write_lock(&tbl->lock);
 528                 list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
 529                         if (time_before(now, en->lastuse+ENTRY_TIMEOUT))
 530                                 continue;
 531
 532                         ip_vs_lblcr_free(en);
 533                         atomic_dec(&tbl->entries);
 534                         goal--;
 535                 }
 536                 write_unlock(&tbl->lock);
 537                 if (goal <= 0)
 538                         break;
 539         }
 540         tbl->rover = j;
 541
 542   out:
 543         mod_timer(&tbl->periodic_timer, jiffies+CHECK_EXPIRE_INTERVAL);
 544 }
 545
 546
 547 #ifdef CONFIG_IP_VS_LBLCR_DEBUG
 548 static struct ip_vs_lblcr_table *lblcr_table_list;
 549
 550 /*
 551  *      /proc/net/ip_vs_lblcr to display the mappings of
 552  *                  destination IP address <==> its serverSet
 553  */
 554 static int
 555 ip_vs_lblcr_getinfo(char *buffer, char **start, off_t offset, int length)
 556 {
 557         off_t pos=0, begin;
 558         int len=0, size;
 559         struct ip_vs_lblcr_table *tbl;
 560         unsigned long now = jiffies;
 561         int i;
 562         struct ip_vs_lblcr_entry *en;
 563
 564         tbl = lblcr_table_list;
 565
 566         size = sprintf(buffer, "LastTime Dest IP address  Server set\n");
 567         pos += size;
 568         len += size;
 569
 570         for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
 571                 read_lock_bh(&tbl->lock);
 572                 list_for_each_entry(en, &tbl->bucket[i], list) {
 573                         char tbuf[16];
 574                         struct ip_vs_dest_list *d;
 575
 576                         sprintf(tbuf, "%u.%u.%u.%u", NIPQUAD(en->addr));
 577                         size = sprintf(buffer+len, "%8lu %-16s ",
 578                                        now-en->lastuse, tbuf);
 579
 580                         read_lock(&en->set.lock);
 581                         for (d=en->set.list; d!=NULL; d=d->next) {
 582                                 size += sprintf(buffer+len+size,
 583                                                 "%u.%u.%u.%u ",
 584                                                 NIPQUAD(d->dest->addr));
 585                         }
 586                         read_unlock(&en->set.lock);
 587                         size += sprintf(buffer+len+size, "\n");
 588                         len += size;
 589                         pos += size;
 590                         if (pos <= offset)
 591                                 len=0;
 592                         if (pos >= offset+length) {
 593                                 read_unlock_bh(&tbl->lock);
 594                                 goto done;
 595                         }
 596                 }
 597                 read_unlock_bh(&tbl->lock);
 598         }
 599
 600   done:
 601         begin = len - (pos - offset);
 602         *start = buffer + begin;
 603         len -= begin;
 604         if(len>length)
 605                 len = length;
 606         return len;
 607 }
 608 #endif
 609
 610
 611 static int ip_vs_lblcr_init_svc(struct ip_vs_service *svc)
 612 {
 613         int i;
 614         struct ip_vs_lblcr_table *tbl;
 615
 616         /*
 617          *    Allocate the ip_vs_lblcr_table for this service
 618          */
 619         tbl = kmalloc(sizeof(struct ip_vs_lblcr_table), GFP_ATOMIC);
 620         if (tbl == NULL) {
 621                 IP_VS_ERR("ip_vs_lblcr_init_svc(): no memory\n");
 622                 return -ENOMEM;
 623         }
 624         svc->sched_data = tbl;
 625         IP_VS_DBG(6, "LBLCR hash table (memory=%Zdbytes) allocated for "
 626                   "current service\n",
 627                   sizeof(struct ip_vs_lblcr_table));
 628
 629         /*
 630          *    Initialize the hash buckets
 631          */
 632         for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
 633                 INIT_LIST_HEAD(&tbl->bucket[i]);
 634         }
 635         rwlock_init(&tbl->lock);
 636         tbl->max_size = IP_VS_LBLCR_TAB_SIZE*16;
 637         tbl->rover = 0;
 638         tbl->counter = 1;
 639
 640         /*
 641          *    Hook periodic timer for garbage collection
 642          */
 643         init_timer(&tbl->periodic_timer);
 644         tbl->periodic_timer.data = (unsigned long)tbl;
 645         tbl->periodic_timer.function = ip_vs_lblcr_check_expire;
 646         tbl->periodic_timer.expires = jiffies+CHECK_EXPIRE_INTERVAL;
 647         add_timer(&tbl->periodic_timer);
 648
 649 #ifdef CONFIG_IP_VS_LBLCR_DEBUG
 650         lblcr_table_list = tbl;
 651 #endif
 652         return 0;
 653 }
 654
 655
 656 static int ip_vs_lblcr_done_svc(struct ip_vs_service *svc)
 657 {
 658         struct ip_vs_lblcr_table *tbl = svc->sched_data;
 659
 660         /* remove periodic timer */
 661         del_timer_sync(&tbl->periodic_timer);
 662
 663         /* got to clean up table entries here */
 664         ip_vs_lblcr_flush(tbl);
 665
 666         /* release the table itself */
 667         kfree(svc->sched_data);
 668         IP_VS_DBG(6, "LBLCR hash table (memory=%Zdbytes) released\n",
 669                   sizeof(struct ip_vs_lblcr_table));
 670
 671         return 0;
 672 }
 673
 674
 675 static int ip_vs_lblcr_update_svc(struct ip_vs_service *svc)
 676 {
 677         return 0;
 678 }
 679
 680
 681 static inline struct ip_vs_dest *
 682 __ip_vs_wlc_schedule(struct ip_vs_service *svc, struct iphdr *iph)
 683 {
 684         struct ip_vs_dest *dest, *least;
 685         int loh, doh;
 686
 687         /*
 688          * We think the overhead of processing active connections is fifty
 689          * times higher than that of inactive connections in average. (This
 690          * fifty times might not be accurate, we will change it later.) We
 691          * use the following formula to estimate the overhead:
 692          *                dest->activeconns*50 + dest->inactconns
 693          * and the load:
 694          *                (dest overhead) / dest->weight
 695          *
 696          * Remember -- no floats in kernel mode!!!
 697          * The comparison of h1*w2 > h2*w1 is equivalent to that of
 698          *                h1/w1 > h2/w2
 699          * if every weight is larger than zero.
 700          *
 701          * The server with weight=0 is quiesced and will not receive any
 702          * new connection.
 703          */
 704         list_for_each_entry(dest, &svc->destinations, n_list) {
 705                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 706                         continue;
 707
 708                 if (atomic_read(&dest->weight) > 0) {
 709                         least = dest;
 710                         loh = atomic_read(&least->activeconns) * 50
 711                                 + atomic_read(&least->inactconns);
 712                         goto nextstage;
 713                 }
 714         }
 715         return NULL;
 716
 717         /*
 718          *    Find the destination with the least load.
 719          */
 720   nextstage:
 721         list_for_each_entry_continue(dest, &svc->destinations, n_list) {
 722                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 723                         continue;
 724
 725                 doh = atomic_read(&dest->activeconns) * 50
 726                         + atomic_read(&dest->inactconns);
 727                 if (loh * atomic_read(&dest->weight) >
 728                     doh * atomic_read(&least->weight)) {
 729                         least = dest;
 730                         loh = doh;
 731                 }
 732         }
 733
 734         IP_VS_DBG(6, "LBLCR: server %d.%d.%d.%d:%d "
 735                   "activeconns %d refcnt %d weight %d overhead %d\n",
 736                   NIPQUAD(least->addr), ntohs(least->port),
 737                   atomic_read(&least->activeconns),
 738                   atomic_read(&least->refcnt),
 739                   atomic_read(&least->weight), loh);
 740
 741         return least;
 742 }
 743
 744
 745 /*
 746  *   If this destination server is overloaded and there is a less loaded
 747  *   server, then return true.
 748  */
 749 static inline int
 750 is_overloaded(struct ip_vs_dest *dest, struct ip_vs_service *svc)
 751 {
 752         if (atomic_read(&dest->activeconns) > atomic_read(&dest->weight)) {
 753                 struct ip_vs_dest *d;
 754
 755                 list_for_each_entry(d, &svc->destinations, n_list) {
 756                         if (atomic_read(&d->activeconns)*2
 757                             < atomic_read(&d->weight)) {
 758                                 return 1;
 759                         }
 760                 }
 761         }
 762         return 0;
 763 }
 764
 765
 766 /*
 767  *    Locality-Based (weighted) Least-Connection scheduling
 768  */
 769 static struct ip_vs_dest *
 770 ip_vs_lblcr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
 771 {
 772         struct ip_vs_dest *dest;
 773         struct ip_vs_lblcr_table *tbl;
 774         struct ip_vs_lblcr_entry *en;
 775         struct iphdr *iph = skb->nh.iph;
 776
 777         IP_VS_DBG(6, "ip_vs_lblcr_schedule(): Scheduling...\n");
 778
 779         tbl = (struct ip_vs_lblcr_table *)svc->sched_data;
 780         en = ip_vs_lblcr_get(tbl, iph->daddr);
 781         if (en == NULL) {
 782                 dest = __ip_vs_wlc_schedule(svc, iph);
 783                 if (dest == NULL) {
 784                         IP_VS_DBG(1, "no destination available\n");
 785                         return NULL;
 786                 }
 787                 en = ip_vs_lblcr_new(iph->daddr);
 788                 if (en == NULL) {
 789                         return NULL;
 790                 }
 791                 ip_vs_dest_set_insert(&en->set, dest);
 792                 ip_vs_lblcr_hash(tbl, en);
 793         } else {
 794                 dest = ip_vs_dest_set_min(&en->set);
 795                 if (!dest || is_overloaded(dest, svc)) {
 796                         dest = __ip_vs_wlc_schedule(svc, iph);
 797                         if (dest == NULL) {
 798                                 IP_VS_DBG(1, "no destination available\n");
 799                                 return NULL;
 800                         }
 801                         ip_vs_dest_set_insert(&en->set, dest);
 802                 }
 803                 if (atomic_read(&en->set.size) > 1 &&
 804                     jiffies-en->set.lastmod > sysctl_ip_vs_lblcr_expiration) {
 805                         struct ip_vs_dest *m;
 806                         m = ip_vs_dest_set_max(&en->set);
 807                         if (m)
 808                                 ip_vs_dest_set_erase(&en->set, m);
 809                 }
 810         }
 811         en->lastuse = jiffies;
 812
 813         IP_VS_DBG(6, "LBLCR: destination IP address %u.%u.%u.%u "
 814                   "--> server %u.%u.%u.%u:%d\n",
 815                   NIPQUAD(en->addr),
 816                   NIPQUAD(dest->addr),
 817                   ntohs(dest->port));
 818
 819         return dest;
 820 }
 821
 822
 823 /*
 824  *      IPVS LBLCR Scheduler structure
 825  */
 826 static struct ip_vs_scheduler ip_vs_lblcr_scheduler =
 827 {
 828         .name =                 "lblcr",
 829         .refcnt =               ATOMIC_INIT(0),
 830         .module =               THIS_MODULE,
 831         .init_service =         ip_vs_lblcr_init_svc,
 832         .done_service =         ip_vs_lblcr_done_svc,
 833         .update_service =       ip_vs_lblcr_update_svc,
 834         .schedule =             ip_vs_lblcr_schedule,
 835 };
 836
 837
 838 static int __init ip_vs_lblcr_init(void)
 839 {
 840         INIT_LIST_HEAD(&ip_vs_lblcr_scheduler.n_list);
 841         sysctl_header = register_sysctl_table(lblcr_root_table, 0);
 842 #ifdef CONFIG_IP_VS_LBLCR_DEBUG
 843         proc_net_create("ip_vs_lblcr", 0, ip_vs_lblcr_getinfo);
 844 #endif
 845         return register_ip_vs_scheduler(&ip_vs_lblcr_scheduler);
 846 }
 847
 848
 849 static void __exit ip_vs_lblcr_cleanup(void)
 850 {
 851 #ifdef CONFIG_IP_VS_LBLCR_DEBUG
 852         proc_net_remove("ip_vs_lblcr");
 853 #endif
 854         unregister_sysctl_table(sysctl_header);
 855         unregister_ip_vs_scheduler(&ip_vs_lblcr_scheduler);
 856 }
 857
 858
 859 module_init(ip_vs_lblcr_init);
 860 module_exit(ip_vs_lblcr_cleanup);
 861 MODULE_LICENSE("GPL");