pintos-os.org Git - openvswitch/blob - datapath/table-hash.c

   1 /*
   2  * Distributed under the terms of the GNU GPL version 2.
   3  * Copyright (c) 2007, 2008 The Board of Trustees of The Leland
   4  * Stanford Junior University
   5  */
   6
   7 #include "table.h"
   8 #include "crc32.h"
   9 #include "flow.h"
  10 #include "datapath.h"
  11
  12 #include <linux/slab.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/mm.h>
  15 #include <linux/highmem.h>
  16 #include <asm/pgtable.h>
  17
  18 static void *kmem_alloc(size_t);
  19 static void *kmem_zalloc(size_t);
  20 static void kmem_free(void *, size_t);
  21
  22 struct sw_table_hash {
  23         struct sw_table swt;
  24         struct crc32 crc32;
  25         unsigned int n_flows;
  26         unsigned int bucket_mask; /* Number of buckets minus 1. */
  27         struct sw_flow **buckets;
  28 };
  29
  30 static struct sw_flow **find_bucket(struct sw_table *swt,
  31                                                                         const struct sw_flow_key *key)
  32 {
  33         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  34         unsigned int crc = crc32_calculate(&th->crc32, key, sizeof *key);
  35         return &th->buckets[crc & th->bucket_mask];
  36 }
  37
  38 static struct sw_flow *table_hash_lookup(struct sw_table *swt,
  39                                                                                  const struct sw_flow_key *key)
  40 {
  41         struct sw_flow *flow = *find_bucket(swt, key);
  42         return flow && !memcmp(&flow->key, key, sizeof *key) ? flow : NULL;
  43 }
  44
  45 static int table_hash_insert(struct sw_table *swt, struct sw_flow *flow)
  46 {
  47         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  48         struct sw_flow **bucket;
  49         int retval;
  50
  51         if (flow->key.wildcards != 0)
  52                 return 0;
  53
  54         bucket = find_bucket(swt, &flow->key);
  55         if (*bucket == NULL) {
  56                 th->n_flows++;
  57                 rcu_assign_pointer(*bucket, flow);
  58                 retval = 1;
  59         } else {
  60                 struct sw_flow *old_flow = *bucket;
  61                 if (!memcmp(&old_flow->key, &flow->key, sizeof flow->key)) {
  62                         rcu_assign_pointer(*bucket, flow);
  63                         flow_deferred_free(old_flow);
  64                         retval = 1;
  65                 } else {
  66                         retval = 0;
  67                 }
  68         }
  69         return retval;
  70 }
  71
  72 /* Caller must update n_flows. */
  73 static int do_delete(struct sw_flow **bucket, struct sw_flow *flow)
  74 {
  75         rcu_assign_pointer(*bucket, NULL);
  76         flow_deferred_free(flow);
  77         return 1;
  78 }
  79
  80 /* Returns number of deleted flows.  We can ignore the priority
  81  * argument, since all exact-match entries are the same (highest)
  82  * priority. */
  83 static int table_hash_delete(struct sw_table *swt,
  84                                                          const struct sw_flow_key *key,
  85                                                          uint16_t priority, int strict)
  86 {
  87         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  88         unsigned int count = 0;
  89
  90         if (key->wildcards == 0) {
  91                 struct sw_flow **bucket = find_bucket(swt, key);
  92                 struct sw_flow *flow = *bucket;
  93                 if (flow && !memcmp(&flow->key, key, sizeof *key))
  94                         count = do_delete(bucket, flow);
  95         } else {
  96                 unsigned int i;
  97
  98                 for (i = 0; i <= th->bucket_mask; i++) {
  99                         struct sw_flow **bucket = &th->buckets[i];
 100                         struct sw_flow *flow = *bucket;
 101                         if (flow && flow_del_matches(&flow->key, key, strict))
 102                                 count += do_delete(bucket, flow);
 103                 }
 104         }
 105         th->n_flows -= count;
 106         return count;
 107 }
 108
 109 static int table_hash_timeout(struct datapath *dp, struct sw_table *swt)
 110 {
 111         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 112         unsigned int i;
 113         int count = 0;
 114
 115         mutex_lock(&dp_mutex);
 116         for (i = 0; i <= th->bucket_mask; i++) {
 117                 struct sw_flow **bucket = &th->buckets[i];
 118                 struct sw_flow *flow = *bucket;
 119                 if (flow && flow_timeout(flow)) {
 120                         count += do_delete(bucket, flow);
 121                         if (dp->flags & OFPC_SEND_FLOW_EXP)
 122                                 dp_send_flow_expired(dp, flow);
 123                 }
 124         }
 125         th->n_flows -= count;
 126         mutex_unlock(&dp_mutex);
 127
 128         return count;
 129 }
 130
 131 static void table_hash_destroy(struct sw_table *swt)
 132 {
 133         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 134         unsigned int i;
 135         for (i = 0; i <= th->bucket_mask; i++)
 136         if (th->buckets[i])
 137                 flow_free(th->buckets[i]);
 138         kmem_free(th->buckets, (th->bucket_mask + 1) * sizeof *th->buckets);
 139         kfree(th);
 140 }
 141
 142 static int table_hash_iterate(struct sw_table *swt,
 143                               const struct sw_flow_key *key,
 144                               struct sw_table_position *position,
 145                               int (*callback)(struct sw_flow *, void *private),
 146                               void *private)
 147 {
 148         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 149
 150         if (position->private[0] > th->bucket_mask)
 151                 return 0;
 152
 153         if (key->wildcards == 0) {
 154                 struct sw_flow *flow;
 155                 int error;
 156
 157                 flow = table_hash_lookup(swt, key);
 158                 if (!flow)
 159                         return 0;
 160
 161                 error = callback(flow, private);
 162                 if (!error)
 163                         position->private[0] = -1;
 164                 return error;
 165         } else {
 166                 int i;
 167
 168                 for (i = position->private[0]; i <= th->bucket_mask; i++) {
 169                         struct sw_flow *flow = th->buckets[i];
 170                         if (flow && flow_matches(key, &flow->key)) {
 171                                 int error = callback(flow, private);
 172                                 if (error) {
 173                                         position->private[0] = i;
 174                                         return error;
 175                                 }
 176                         }
 177                 }
 178                 return 0;
 179         }
 180 }
 181 static void table_hash_stats(struct sw_table *swt,
 182                                  struct sw_table_stats *stats)
 183 {
 184         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 185         stats->name = "hash";
 186         stats->n_flows = th->n_flows;
 187         stats->max_flows = th->bucket_mask + 1;
 188 }
 189
 190 struct sw_table *table_hash_create(unsigned int polynomial,
 191                         unsigned int n_buckets)
 192 {
 193         struct sw_table_hash *th;
 194         struct sw_table *swt;
 195
 196         th = kmalloc(sizeof *th, GFP_KERNEL);
 197         if (th == NULL)
 198                 return NULL;
 199
 200         BUG_ON(n_buckets & (n_buckets - 1));
 201         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 202         if (th->buckets == NULL) {
 203                 printk("failed to allocate %u buckets\n", n_buckets);
 204                 kfree(th);
 205                 return NULL;
 206         }
 207         th->bucket_mask = n_buckets - 1;
 208
 209         swt = &th->swt;
 210         swt->lookup = table_hash_lookup;
 211         swt->insert = table_hash_insert;
 212         swt->delete = table_hash_delete;
 213         swt->timeout = table_hash_timeout;
 214         swt->destroy = table_hash_destroy;
 215         swt->iterate = table_hash_iterate;
 216         swt->stats = table_hash_stats;
 217
 218         crc32_init(&th->crc32, polynomial);
 219         th->n_flows = 0;
 220
 221         return swt;
 222 }
 223
 224 /* Double-hashing table. */
 225
 226 struct sw_table_hash2 {
 227         struct sw_table swt;
 228         struct sw_table *subtable[2];
 229 };
 230
 231 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 232                                                                                   const struct sw_flow_key *key)
 233 {
 234         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 235         int i;
 236
 237         for (i = 0; i < 2; i++) {
 238                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 239                 if (flow && !memcmp(&flow->key, key, sizeof *key))
 240                         return flow;
 241         }
 242         return NULL;
 243 }
 244
 245 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 246 {
 247         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 248
 249         if (table_hash_insert(t2->subtable[0], flow))
 250                 return 1;
 251         return table_hash_insert(t2->subtable[1], flow);
 252 }
 253
 254 static int table_hash2_delete(struct sw_table *swt,
 255                                                           const struct sw_flow_key *key,
 256                                                           uint16_t priority, int strict)
 257 {
 258         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 259         return (table_hash_delete(t2->subtable[0], key, priority, strict)
 260                         + table_hash_delete(t2->subtable[1], key, priority, strict));
 261 }
 262
 263 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 264 {
 265         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 266         return (table_hash_timeout(dp, t2->subtable[0])
 267                         + table_hash_timeout(dp, t2->subtable[1]));
 268 }
 269
 270 static void table_hash2_destroy(struct sw_table *swt)
 271 {
 272         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 273         table_hash_destroy(t2->subtable[0]);
 274         table_hash_destroy(t2->subtable[1]);
 275         kfree(t2);
 276 }
 277
 278 static int table_hash2_iterate(struct sw_table *swt,
 279                                const struct sw_flow_key *key,
 280                                struct sw_table_position *position,
 281                                int (*callback)(struct sw_flow *, void *),
 282                                void *private)
 283 {
 284         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 285         int i;
 286
 287         for (i = position->private[1]; i < 2; i++) {
 288                 int error = table_hash_iterate(t2->subtable[i], key, position,
 289                                                callback, private);
 290                 if (error) {
 291                         return error;
 292                 }
 293                 position->private[0] = 0;
 294                 position->private[1]++;
 295         }
 296         return 0;
 297 }
 298
 299 static void table_hash2_stats(struct sw_table *swt,
 300                                  struct sw_table_stats *stats)
 301 {
 302         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 303         struct sw_table_stats substats[2];
 304         int i;
 305
 306         for (i = 0; i < 2; i++)
 307                 table_hash_stats(t2->subtable[i], &substats[i]);
 308         stats->name = "hash2";
 309         stats->n_flows = substats[0].n_flows + substats[1].n_flows;
 310         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 311 }
 312
 313 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 314                                                                         unsigned int poly1, unsigned int buckets1)
 315
 316 {
 317         struct sw_table_hash2 *t2;
 318         struct sw_table *swt;
 319
 320         t2 = kmalloc(sizeof *t2, GFP_KERNEL);
 321         if (t2 == NULL)
 322                 return NULL;
 323
 324         t2->subtable[0] = table_hash_create(poly0, buckets0);
 325         if (t2->subtable[0] == NULL)
 326                 goto out_free_t2;
 327
 328         t2->subtable[1] = table_hash_create(poly1, buckets1);
 329         if (t2->subtable[1] == NULL)
 330                 goto out_free_subtable0;
 331
 332         swt = &t2->swt;
 333         swt->lookup = table_hash2_lookup;
 334         swt->insert = table_hash2_insert;
 335         swt->delete = table_hash2_delete;
 336         swt->timeout = table_hash2_timeout;
 337         swt->destroy = table_hash2_destroy;
 338         swt->iterate = table_hash2_iterate;
 339         swt->stats = table_hash2_stats;
 340
 341         return swt;
 342
 343 out_free_subtable0:
 344         table_hash_destroy(t2->subtable[0]);
 345 out_free_t2:
 346         kfree(t2);
 347         return NULL;
 348 }
 349
 350 /* From fs/xfs/linux-2.4/kmem.c. */
 351
 352 static void *
 353 kmem_alloc(size_t size)
 354 {
 355         void *ptr;
 356
 357 #ifdef KMALLOC_MAX_SIZE
 358         if (size > KMALLOC_MAX_SIZE)
 359                 return NULL;
 360 #endif
 361         ptr = kmalloc(size, GFP_KERNEL);
 362         if (!ptr) {
 363                 ptr = vmalloc(size);
 364                 if (ptr)
 365                         printk("openflow: used vmalloc for %lu bytes\n",
 366                                         (unsigned long)size);
 367         }
 368         return ptr;
 369 }
 370
 371 static void *
 372 kmem_zalloc(size_t size)
 373 {
 374         void *ptr = kmem_alloc(size);
 375         if (ptr)
 376                 memset(ptr, 0, size);
 377         return ptr;
 378 }
 379
 380 static void
 381 kmem_free(void *ptr, size_t size)
 382 {
 383         if (((unsigned long)ptr < VMALLOC_START) ||
 384                 ((unsigned long)ptr >= VMALLOC_END)) {
 385                 kfree(ptr);
 386         } else {
 387                 vfree(ptr);
 388         }
 389 }