Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * IPVS: Locality-Based Least-Connection scheduling module |
| 3 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4 | * Authors: Wensong Zhang <wensong@gnuchina.org> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * Changes: |
| 12 | * Martin Hamilton : fixed the terrible locking bugs |
| 13 | * *lock(tbl->lock) ==> *lock(&tbl->lock) |
| 14 | * Wensong Zhang : fixed the uninitilized tbl->lock bug |
| 15 | * Wensong Zhang : added doing full expiration check to |
| 16 | * collect stale entries of 24+ hours when |
| 17 | * no partial expire check in a half hour |
| 18 | * Julian Anastasov : replaced del_timer call with del_timer_sync |
| 19 | * to avoid the possible race between timer |
| 20 | * handler and del_timer thread in SMP |
| 21 | * |
| 22 | */ |
| 23 | |
| 24 | /* |
| 25 | * The lblc algorithm is as follows (pseudo code): |
| 26 | * |
| 27 | * if cachenode[dest_ip] is null then |
| 28 | * n, cachenode[dest_ip] <- {weighted least-conn node}; |
| 29 | * else |
| 30 | * n <- cachenode[dest_ip]; |
| 31 | * if (n is dead) OR |
| 32 | * (n.conns>n.weight AND |
| 33 | * there is a node m with m.conns<m.weight/2) then |
| 34 | * n, cachenode[dest_ip] <- {weighted least-conn node}; |
| 35 | * |
| 36 | * return n; |
| 37 | * |
| 38 | * Thanks must go to Wenzhuo Zhang for talking WCCP to me and pushing |
| 39 | * me to write this module. |
| 40 | */ |
| 41 | |
Arnaldo Carvalho de Melo | 14c8502 | 2005-12-27 02:43:12 -0200 | [diff] [blame] | 42 | #include <linux/ip.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | #include <linux/module.h> |
| 44 | #include <linux/kernel.h> |
Arnaldo Carvalho de Melo | 14c8502 | 2005-12-27 02:43:12 -0200 | [diff] [blame] | 45 | #include <linux/skbuff.h> |
Al Viro | d7fe0f2 | 2006-12-03 23:15:30 -0500 | [diff] [blame] | 46 | #include <linux/jiffies.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
| 48 | /* for sysctl */ |
| 49 | #include <linux/fs.h> |
| 50 | #include <linux/sysctl.h> |
| 51 | |
| 52 | #include <net/ip_vs.h> |
| 53 | |
| 54 | |
| 55 | /* |
| 56 | * It is for garbage collection of stale IPVS lblc entries, |
| 57 | * when the table is full. |
| 58 | */ |
| 59 | #define CHECK_EXPIRE_INTERVAL (60*HZ) |
| 60 | #define ENTRY_TIMEOUT (6*60*HZ) |
| 61 | |
| 62 | /* |
| 63 | * It is for full expiration check. |
| 64 | * When there is no partial expiration check (garbage collection) |
| 65 | * in a half hour, do a full expiration check to collect stale |
| 66 | * entries that haven't been touched for a day. |
| 67 | */ |
| 68 | #define COUNT_FOR_FULL_EXPIRATION 30 |
| 69 | static int sysctl_ip_vs_lblc_expiration = 24*60*60*HZ; |
| 70 | |
| 71 | |
| 72 | /* |
| 73 | * for IPVS lblc entry hash table |
| 74 | */ |
| 75 | #ifndef CONFIG_IP_VS_LBLC_TAB_BITS |
| 76 | #define CONFIG_IP_VS_LBLC_TAB_BITS 10 |
| 77 | #endif |
| 78 | #define IP_VS_LBLC_TAB_BITS CONFIG_IP_VS_LBLC_TAB_BITS |
| 79 | #define IP_VS_LBLC_TAB_SIZE (1 << IP_VS_LBLC_TAB_BITS) |
| 80 | #define IP_VS_LBLC_TAB_MASK (IP_VS_LBLC_TAB_SIZE - 1) |
| 81 | |
| 82 | |
| 83 | /* |
| 84 | * IPVS lblc entry represents an association between destination |
| 85 | * IP address and its destination server |
| 86 | */ |
| 87 | struct ip_vs_lblc_entry { |
| 88 | struct list_head list; |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 89 | int af; /* address family */ |
| 90 | union nf_inet_addr addr; /* destination IP address */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | struct ip_vs_dest *dest; /* real server (cache) */ |
| 92 | unsigned long lastuse; /* last used time */ |
| 93 | }; |
| 94 | |
| 95 | |
| 96 | /* |
| 97 | * IPVS lblc hash table |
| 98 | */ |
| 99 | struct ip_vs_lblc_table { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | struct list_head bucket[IP_VS_LBLC_TAB_SIZE]; /* hash bucket */ |
| 101 | atomic_t entries; /* number of entries */ |
| 102 | int max_size; /* maximum size of entries */ |
| 103 | struct timer_list periodic_timer; /* collect stale entries */ |
| 104 | int rover; /* rover for expire check */ |
| 105 | int counter; /* counter for no expire */ |
| 106 | }; |
| 107 | |
| 108 | |
| 109 | /* |
| 110 | * IPVS LBLC sysctl table |
| 111 | */ |
| 112 | |
| 113 | static ctl_table vs_vars_table[] = { |
| 114 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | .procname = "lblc_expiration", |
| 116 | .data = &sysctl_ip_vs_lblc_expiration, |
| 117 | .maxlen = sizeof(int), |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 118 | .mode = 0644, |
Alexey Dobriyan | 6d9f239 | 2008-11-03 18:21:05 -0800 | [diff] [blame] | 119 | .proc_handler = proc_dointvec_jiffies, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | }, |
| 121 | { .ctl_name = 0 } |
| 122 | }; |
| 123 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | static struct ctl_table_header * sysctl_header; |
| 125 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | static inline void ip_vs_lblc_free(struct ip_vs_lblc_entry *en) |
| 127 | { |
| 128 | list_del(&en->list); |
| 129 | /* |
| 130 | * We don't kfree dest because it is refered either by its service |
| 131 | * or the trash dest list. |
| 132 | */ |
| 133 | atomic_dec(&en->dest->refcnt); |
| 134 | kfree(en); |
| 135 | } |
| 136 | |
| 137 | |
| 138 | /* |
| 139 | * Returns hash value for IPVS LBLC entry |
| 140 | */ |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 141 | static inline unsigned |
| 142 | ip_vs_lblc_hashkey(int af, const union nf_inet_addr *addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | { |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 144 | __be32 addr_fold = addr->ip; |
| 145 | |
| 146 | #ifdef CONFIG_IP_VS_IPV6 |
| 147 | if (af == AF_INET6) |
| 148 | addr_fold = addr->ip6[0]^addr->ip6[1]^ |
| 149 | addr->ip6[2]^addr->ip6[3]; |
| 150 | #endif |
| 151 | return (ntohl(addr_fold)*2654435761UL) & IP_VS_LBLC_TAB_MASK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | } |
| 153 | |
| 154 | |
| 155 | /* |
| 156 | * Hash an entry in the ip_vs_lblc_table. |
| 157 | * returns bool success. |
| 158 | */ |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 159 | static void |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | ip_vs_lblc_hash(struct ip_vs_lblc_table *tbl, struct ip_vs_lblc_entry *en) |
| 161 | { |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 162 | unsigned hash = ip_vs_lblc_hashkey(en->af, &en->addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | list_add(&en->list, &tbl->bucket[hash]); |
| 165 | atomic_inc(&tbl->entries); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | } |
| 167 | |
| 168 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | /* |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 170 | * Get ip_vs_lblc_entry associated with supplied parameters. Called under read |
| 171 | * lock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | */ |
| 173 | static inline struct ip_vs_lblc_entry * |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 174 | ip_vs_lblc_get(int af, struct ip_vs_lblc_table *tbl, |
| 175 | const union nf_inet_addr *addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | { |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 177 | unsigned hash = ip_vs_lblc_hashkey(af, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | struct ip_vs_lblc_entry *en; |
| 179 | |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 180 | list_for_each_entry(en, &tbl->bucket[hash], list) |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 181 | if (ip_vs_addr_equal(af, &en->addr, addr)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | return en; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | |
| 184 | return NULL; |
| 185 | } |
| 186 | |
| 187 | |
| 188 | /* |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 189 | * Create or update an ip_vs_lblc_entry, which is a mapping of a destination IP |
| 190 | * address to a server. Called under write lock. |
| 191 | */ |
| 192 | static inline struct ip_vs_lblc_entry * |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 193 | ip_vs_lblc_new(struct ip_vs_lblc_table *tbl, const union nf_inet_addr *daddr, |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 194 | struct ip_vs_dest *dest) |
| 195 | { |
| 196 | struct ip_vs_lblc_entry *en; |
| 197 | |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 198 | en = ip_vs_lblc_get(dest->af, tbl, daddr); |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 199 | if (!en) { |
| 200 | en = kmalloc(sizeof(*en), GFP_ATOMIC); |
| 201 | if (!en) { |
| 202 | IP_VS_ERR("ip_vs_lblc_new(): no memory\n"); |
| 203 | return NULL; |
| 204 | } |
| 205 | |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 206 | en->af = dest->af; |
| 207 | ip_vs_addr_copy(dest->af, &en->addr, daddr); |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 208 | en->lastuse = jiffies; |
| 209 | |
| 210 | atomic_inc(&dest->refcnt); |
| 211 | en->dest = dest; |
| 212 | |
| 213 | ip_vs_lblc_hash(tbl, en); |
| 214 | } else if (en->dest != dest) { |
| 215 | atomic_dec(&en->dest->refcnt); |
| 216 | atomic_inc(&dest->refcnt); |
| 217 | en->dest = dest; |
| 218 | } |
| 219 | |
| 220 | return en; |
| 221 | } |
| 222 | |
| 223 | |
| 224 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | * Flush all the entries of the specified table. |
| 226 | */ |
| 227 | static void ip_vs_lblc_flush(struct ip_vs_lblc_table *tbl) |
| 228 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | struct ip_vs_lblc_entry *en, *nxt; |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 230 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | |
| 232 | for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 233 | list_for_each_entry_safe(en, nxt, &tbl->bucket[i], list) { |
| 234 | ip_vs_lblc_free(en); |
| 235 | atomic_dec(&tbl->entries); |
| 236 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | } |
| 238 | } |
| 239 | |
| 240 | |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 241 | static inline void ip_vs_lblc_full_check(struct ip_vs_service *svc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | { |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 243 | struct ip_vs_lblc_table *tbl = svc->sched_data; |
| 244 | struct ip_vs_lblc_entry *en, *nxt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | unsigned long now = jiffies; |
| 246 | int i, j; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | |
| 248 | for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) { |
| 249 | j = (j + 1) & IP_VS_LBLC_TAB_MASK; |
| 250 | |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 251 | write_lock(&svc->sched_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) { |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 253 | if (time_before(now, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | en->lastuse + sysctl_ip_vs_lblc_expiration)) |
| 255 | continue; |
| 256 | |
| 257 | ip_vs_lblc_free(en); |
| 258 | atomic_dec(&tbl->entries); |
| 259 | } |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 260 | write_unlock(&svc->sched_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | } |
| 262 | tbl->rover = j; |
| 263 | } |
| 264 | |
| 265 | |
| 266 | /* |
| 267 | * Periodical timer handler for IPVS lblc table |
| 268 | * It is used to collect stale entries when the number of entries |
| 269 | * exceeds the maximum size of the table. |
| 270 | * |
| 271 | * Fixme: we probably need more complicated algorithm to collect |
| 272 | * entries that have not been used for a long time even |
| 273 | * if the number of entries doesn't exceed the maximum size |
| 274 | * of the table. |
| 275 | * The full expiration check is for this purpose now. |
| 276 | */ |
| 277 | static void ip_vs_lblc_check_expire(unsigned long data) |
| 278 | { |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 279 | struct ip_vs_service *svc = (struct ip_vs_service *) data; |
| 280 | struct ip_vs_lblc_table *tbl = svc->sched_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | unsigned long now = jiffies; |
| 282 | int goal; |
| 283 | int i, j; |
| 284 | struct ip_vs_lblc_entry *en, *nxt; |
| 285 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) { |
| 287 | /* do full expiration check */ |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 288 | ip_vs_lblc_full_check(svc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 289 | tbl->counter = 1; |
| 290 | goto out; |
| 291 | } |
| 292 | |
| 293 | if (atomic_read(&tbl->entries) <= tbl->max_size) { |
| 294 | tbl->counter++; |
| 295 | goto out; |
| 296 | } |
| 297 | |
| 298 | goal = (atomic_read(&tbl->entries) - tbl->max_size)*4/3; |
| 299 | if (goal > tbl->max_size/2) |
| 300 | goal = tbl->max_size/2; |
| 301 | |
| 302 | for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) { |
| 303 | j = (j + 1) & IP_VS_LBLC_TAB_MASK; |
| 304 | |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 305 | write_lock(&svc->sched_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) { |
| 307 | if (time_before(now, en->lastuse + ENTRY_TIMEOUT)) |
| 308 | continue; |
| 309 | |
| 310 | ip_vs_lblc_free(en); |
| 311 | atomic_dec(&tbl->entries); |
| 312 | goal--; |
| 313 | } |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 314 | write_unlock(&svc->sched_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | if (goal <= 0) |
| 316 | break; |
| 317 | } |
| 318 | tbl->rover = j; |
| 319 | |
| 320 | out: |
| 321 | mod_timer(&tbl->periodic_timer, jiffies+CHECK_EXPIRE_INTERVAL); |
| 322 | } |
| 323 | |
| 324 | |
| 325 | static int ip_vs_lblc_init_svc(struct ip_vs_service *svc) |
| 326 | { |
| 327 | int i; |
| 328 | struct ip_vs_lblc_table *tbl; |
| 329 | |
| 330 | /* |
| 331 | * Allocate the ip_vs_lblc_table for this service |
| 332 | */ |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 333 | tbl = kmalloc(sizeof(*tbl), GFP_ATOMIC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | if (tbl == NULL) { |
| 335 | IP_VS_ERR("ip_vs_lblc_init_svc(): no memory\n"); |
| 336 | return -ENOMEM; |
| 337 | } |
| 338 | svc->sched_data = tbl; |
| 339 | IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) allocated for " |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 340 | "current service\n", sizeof(*tbl)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | |
| 342 | /* |
| 343 | * Initialize the hash buckets |
| 344 | */ |
| 345 | for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) { |
| 346 | INIT_LIST_HEAD(&tbl->bucket[i]); |
| 347 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | tbl->max_size = IP_VS_LBLC_TAB_SIZE*16; |
| 349 | tbl->rover = 0; |
| 350 | tbl->counter = 1; |
| 351 | |
| 352 | /* |
| 353 | * Hook periodic timer for garbage collection |
| 354 | */ |
Pavel Emelyanov | b24b8a2 | 2008-01-23 21:20:07 -0800 | [diff] [blame] | 355 | setup_timer(&tbl->periodic_timer, ip_vs_lblc_check_expire, |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 356 | (unsigned long)svc); |
| 357 | mod_timer(&tbl->periodic_timer, jiffies + CHECK_EXPIRE_INTERVAL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | |
| 359 | return 0; |
| 360 | } |
| 361 | |
| 362 | |
| 363 | static int ip_vs_lblc_done_svc(struct ip_vs_service *svc) |
| 364 | { |
| 365 | struct ip_vs_lblc_table *tbl = svc->sched_data; |
| 366 | |
| 367 | /* remove periodic timer */ |
| 368 | del_timer_sync(&tbl->periodic_timer); |
| 369 | |
| 370 | /* got to clean up table entries here */ |
| 371 | ip_vs_lblc_flush(tbl); |
| 372 | |
| 373 | /* release the table itself */ |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 374 | kfree(tbl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 375 | IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) released\n", |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 376 | sizeof(*tbl)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | |
| 378 | return 0; |
| 379 | } |
| 380 | |
| 381 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | static inline struct ip_vs_dest * |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 383 | __ip_vs_lblc_schedule(struct ip_vs_service *svc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | { |
| 385 | struct ip_vs_dest *dest, *least; |
| 386 | int loh, doh; |
| 387 | |
| 388 | /* |
| 389 | * We think the overhead of processing active connections is fifty |
| 390 | * times higher than that of inactive connections in average. (This |
| 391 | * fifty times might not be accurate, we will change it later.) We |
| 392 | * use the following formula to estimate the overhead: |
| 393 | * dest->activeconns*50 + dest->inactconns |
| 394 | * and the load: |
| 395 | * (dest overhead) / dest->weight |
| 396 | * |
| 397 | * Remember -- no floats in kernel mode!!! |
| 398 | * The comparison of h1*w2 > h2*w1 is equivalent to that of |
| 399 | * h1/w1 > h2/w2 |
| 400 | * if every weight is larger than zero. |
| 401 | * |
| 402 | * The server with weight=0 is quiesced and will not receive any |
| 403 | * new connection. |
| 404 | */ |
| 405 | list_for_each_entry(dest, &svc->destinations, n_list) { |
| 406 | if (dest->flags & IP_VS_DEST_F_OVERLOAD) |
| 407 | continue; |
| 408 | if (atomic_read(&dest->weight) > 0) { |
| 409 | least = dest; |
| 410 | loh = atomic_read(&least->activeconns) * 50 |
| 411 | + atomic_read(&least->inactconns); |
| 412 | goto nextstage; |
| 413 | } |
| 414 | } |
| 415 | return NULL; |
| 416 | |
| 417 | /* |
| 418 | * Find the destination with the least load. |
| 419 | */ |
| 420 | nextstage: |
| 421 | list_for_each_entry_continue(dest, &svc->destinations, n_list) { |
| 422 | if (dest->flags & IP_VS_DEST_F_OVERLOAD) |
| 423 | continue; |
| 424 | |
| 425 | doh = atomic_read(&dest->activeconns) * 50 |
| 426 | + atomic_read(&dest->inactconns); |
| 427 | if (loh * atomic_read(&dest->weight) > |
| 428 | doh * atomic_read(&least->weight)) { |
| 429 | least = dest; |
| 430 | loh = doh; |
| 431 | } |
| 432 | } |
| 433 | |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 434 | IP_VS_DBG_BUF(6, "LBLC: server %s:%d " |
| 435 | "activeconns %d refcnt %d weight %d overhead %d\n", |
| 436 | IP_VS_DBG_ADDR(least->af, &least->addr), |
| 437 | ntohs(least->port), |
| 438 | atomic_read(&least->activeconns), |
| 439 | atomic_read(&least->refcnt), |
| 440 | atomic_read(&least->weight), loh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | |
| 442 | return least; |
| 443 | } |
| 444 | |
| 445 | |
| 446 | /* |
| 447 | * If this destination server is overloaded and there is a less loaded |
| 448 | * server, then return true. |
| 449 | */ |
| 450 | static inline int |
| 451 | is_overloaded(struct ip_vs_dest *dest, struct ip_vs_service *svc) |
| 452 | { |
| 453 | if (atomic_read(&dest->activeconns) > atomic_read(&dest->weight)) { |
| 454 | struct ip_vs_dest *d; |
| 455 | |
| 456 | list_for_each_entry(d, &svc->destinations, n_list) { |
| 457 | if (atomic_read(&d->activeconns)*2 |
| 458 | < atomic_read(&d->weight)) { |
| 459 | return 1; |
| 460 | } |
| 461 | } |
| 462 | } |
| 463 | return 0; |
| 464 | } |
| 465 | |
| 466 | |
| 467 | /* |
| 468 | * Locality-Based (weighted) Least-Connection scheduling |
| 469 | */ |
| 470 | static struct ip_vs_dest * |
| 471 | ip_vs_lblc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb) |
| 472 | { |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 473 | struct ip_vs_lblc_table *tbl = svc->sched_data; |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 474 | struct ip_vs_iphdr iph; |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 475 | struct ip_vs_dest *dest = NULL; |
| 476 | struct ip_vs_lblc_entry *en; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 478 | ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph); |
| 479 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | IP_VS_DBG(6, "ip_vs_lblc_schedule(): Scheduling...\n"); |
| 481 | |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 482 | /* First look in our cache */ |
| 483 | read_lock(&svc->sched_lock); |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 484 | en = ip_vs_lblc_get(svc->af, tbl, &iph.daddr); |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 485 | if (en) { |
| 486 | /* We only hold a read lock, but this is atomic */ |
| 487 | en->lastuse = jiffies; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 489 | /* |
| 490 | * If the destination is not available, i.e. it's in the trash, |
| 491 | * we must ignore it, as it may be removed from under our feet, |
| 492 | * if someone drops our reference count. Our caller only makes |
| 493 | * sure that destinations, that are not in the trash, are not |
| 494 | * moved to the trash, while we are scheduling. But anyone can |
| 495 | * free up entries from the trash at any time. |
| 496 | */ |
| 497 | |
| 498 | if (en->dest->flags & IP_VS_DEST_F_AVAILABLE) |
| 499 | dest = en->dest; |
| 500 | } |
| 501 | read_unlock(&svc->sched_lock); |
| 502 | |
| 503 | /* If the destination has a weight and is not overloaded, use it */ |
| 504 | if (dest && atomic_read(&dest->weight) > 0 && !is_overloaded(dest, svc)) |
| 505 | goto out; |
| 506 | |
| 507 | /* No cache entry or it is invalid, time to schedule */ |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 508 | dest = __ip_vs_lblc_schedule(svc); |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 509 | if (!dest) { |
Simon Horman | 68888d1 | 2008-12-29 18:37:36 -0800 | [diff] [blame^] | 510 | IP_VS_ERR_RL("LBLC: no destination available\n"); |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 511 | return NULL; |
| 512 | } |
| 513 | |
| 514 | /* If we fail to create a cache entry, we'll just use the valid dest */ |
| 515 | write_lock(&svc->sched_lock); |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 516 | ip_vs_lblc_new(tbl, &iph.daddr, dest); |
Sven Wegener | 39ac50d | 2008-08-18 00:52:08 +0200 | [diff] [blame] | 517 | write_unlock(&svc->sched_lock); |
| 518 | |
| 519 | out: |
Julius Volz | 4454837 | 2008-11-03 17:08:28 -0800 | [diff] [blame] | 520 | IP_VS_DBG_BUF(6, "LBLC: destination IP address %s --> server %s:%d\n", |
| 521 | IP_VS_DBG_ADDR(svc->af, &iph.daddr), |
| 522 | IP_VS_DBG_ADDR(svc->af, &dest->addr), ntohs(dest->port)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | |
| 524 | return dest; |
| 525 | } |
| 526 | |
| 527 | |
| 528 | /* |
| 529 | * IPVS LBLC Scheduler structure |
| 530 | */ |
| 531 | static struct ip_vs_scheduler ip_vs_lblc_scheduler = |
| 532 | { |
| 533 | .name = "lblc", |
| 534 | .refcnt = ATOMIC_INIT(0), |
| 535 | .module = THIS_MODULE, |
Sven Wegener | d149ccc | 2008-08-10 09:18:02 +0000 | [diff] [blame] | 536 | .n_list = LIST_HEAD_INIT(ip_vs_lblc_scheduler.n_list), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | .init_service = ip_vs_lblc_init_svc, |
| 538 | .done_service = ip_vs_lblc_done_svc, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | .schedule = ip_vs_lblc_schedule, |
| 540 | }; |
| 541 | |
| 542 | |
| 543 | static int __init ip_vs_lblc_init(void) |
| 544 | { |
Pavel Emelyanov | a014bc8 | 2007-12-04 00:43:24 -0800 | [diff] [blame] | 545 | int ret; |
| 546 | |
Pavel Emelyanov | 90754f8 | 2008-01-12 02:33:50 -0800 | [diff] [blame] | 547 | sysctl_header = register_sysctl_paths(net_vs_ctl_path, vs_vars_table); |
Pavel Emelyanov | a014bc8 | 2007-12-04 00:43:24 -0800 | [diff] [blame] | 548 | ret = register_ip_vs_scheduler(&ip_vs_lblc_scheduler); |
| 549 | if (ret) |
| 550 | unregister_sysctl_table(sysctl_header); |
| 551 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | } |
| 553 | |
| 554 | |
| 555 | static void __exit ip_vs_lblc_cleanup(void) |
| 556 | { |
| 557 | unregister_sysctl_table(sysctl_header); |
| 558 | unregister_ip_vs_scheduler(&ip_vs_lblc_scheduler); |
| 559 | } |
| 560 | |
| 561 | |
| 562 | module_init(ip_vs_lblc_init); |
| 563 | module_exit(ip_vs_lblc_cleanup); |
| 564 | MODULE_LICENSE("GPL"); |