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1da177e4 LT |
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 | ||
bf0ff9e5 | 323 | static ctl_table ipvs_ipv4_table[] = { |
1da177e4 LT |
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, | |
bf0ff9e5 | 338 | .child = ipvs_ipv4_table |
1da177e4 LT |
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 | ||
1da177e4 LT |
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"); |