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         atomic_t 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                 atomic_inc(&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                                         && flow_del(old_flow)) {
  63                         rcu_assign_pointer(*bucket, flow);
  64                         flow_deferred_free(old_flow);
  65                         retval = 1;
  66                 } else {
  67                         retval = 0;
  68                 }
  69         }
  70         return retval;
  71 }
  72
  73 /* Caller must update n_flows. */
  74 static int do_delete(struct sw_flow **bucket, struct sw_flow *flow)
  75 {
  76         if (flow_del(flow)) {
  77                 rcu_assign_pointer(*bucket, NULL);
  78                 flow_deferred_free(flow);
  79                 return 1;
  80         }
  81         return 0;
  82 }
  83
  84 /* Returns number of deleted flows.  We can ignore the priority
  85  * argument, since all exact-match entries are the same (highest)
  86  * priority. */
  87 static int table_hash_delete(struct sw_table *swt,
  88                                                          const struct sw_flow_key *key,
  89                                                          uint16_t priority, int strict)
  90 {
  91         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  92         unsigned int count = 0;
  93
  94         if (key->wildcards == 0) {
  95                 struct sw_flow **bucket = find_bucket(swt, key);
  96                 struct sw_flow *flow = *bucket;
  97                 if (flow && !memcmp(&flow->key, key, sizeof *key))
  98                         count = do_delete(bucket, flow);
  99         } else {
 100                 unsigned int i;
 101
 102                 for (i = 0; i <= th->bucket_mask; i++) {
 103                         struct sw_flow **bucket = &th->buckets[i];
 104                         struct sw_flow *flow = *bucket;
 105                         if (flow && flow_del_matches(&flow->key, key, strict))
 106                                 count += do_delete(bucket, flow);
 107                 }
 108         }
 109         if (count)
 110                 atomic_sub(count, &th->n_flows);
 111         return count;
 112 }
 113
 114 static int table_hash_timeout(struct datapath *dp, struct sw_table *swt)
 115 {
 116         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 117         unsigned int i;
 118         int count = 0;
 119
 120         mutex_lock(&dp_mutex);
 121         for (i = 0; i <= th->bucket_mask; i++) {
 122                 struct sw_flow **bucket = &th->buckets[i];
 123                 struct sw_flow *flow = *bucket;
 124                 if (flow && flow_timeout(flow)) {
 125                         count += do_delete(bucket, flow);
 126                         if (dp->flags & OFPC_SEND_FLOW_EXP)
 127                                 dp_send_flow_expired(dp, flow);
 128                 }
 129         }
 130         mutex_unlock(&dp_mutex);
 131
 132         if (count)
 133                 atomic_sub(count, &th->n_flows);
 134         return count;
 135 }
 136
 137 static void table_hash_destroy(struct sw_table *swt)
 138 {
 139         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 140         unsigned int i;
 141         for (i = 0; i <= th->bucket_mask; i++)
 142         if (th->buckets[i])
 143                 flow_free(th->buckets[i]);
 144         kmem_free(th->buckets, (th->bucket_mask + 1) * sizeof *th->buckets);
 145         kfree(th);
 146 }
 147
 148 static int table_hash_iterate(struct sw_table *swt,
 149                               const struct sw_flow_key *key,
 150                               struct sw_table_position *position,
 151                               int (*callback)(struct sw_flow *, void *private),
 152                               void *private)
 153 {
 154         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 155
 156         if (position->private[0] > th->bucket_mask)
 157                 return 0;
 158
 159         if (key->wildcards == 0) {
 160                 struct sw_flow *flow;
 161                 int error;
 162
 163                 flow = table_hash_lookup(swt, key);
 164                 if (!flow)
 165                         return 0;
 166
 167                 error = callback(flow, private);
 168                 if (!error)
 169                         position->private[0] = -1;
 170                 return error;
 171         } else {
 172                 int i;
 173
 174                 for (i = position->private[0]; i <= th->bucket_mask; i++) {
 175                         struct sw_flow *flow = th->buckets[i];
 176                         if (flow && flow_matches(key, &flow->key)) {
 177                                 int error = callback(flow, private);
 178                                 if (error) {
 179                                         position->private[0] = i;
 180                                         return error;
 181                                 }
 182                         }
 183                 }
 184                 return 0;
 185         }
 186 }
 187 static void table_hash_stats(struct sw_table *swt,
 188                                  struct sw_table_stats *stats)
 189 {
 190         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 191         stats->name = "hash";
 192         stats->n_flows = atomic_read(&th->n_flows);
 193         stats->max_flows = th->bucket_mask + 1;
 194 }
 195
 196 struct sw_table *table_hash_create(unsigned int polynomial,
 197                         unsigned int n_buckets)
 198 {
 199         struct sw_table_hash *th;
 200         struct sw_table *swt;
 201
 202         th = kmalloc(sizeof *th, GFP_KERNEL);
 203         if (th == NULL)
 204                 return NULL;
 205
 206         BUG_ON(n_buckets & (n_buckets - 1));
 207         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 208         if (th->buckets == NULL) {
 209                 printk("failed to allocate %u buckets\n", n_buckets);
 210                 kfree(th);
 211                 return NULL;
 212         }
 213         th->bucket_mask = n_buckets - 1;
 214
 215         swt = &th->swt;
 216         swt->lookup = table_hash_lookup;
 217         swt->insert = table_hash_insert;
 218         swt->delete = table_hash_delete;
 219         swt->timeout = table_hash_timeout;
 220         swt->destroy = table_hash_destroy;
 221         swt->iterate = table_hash_iterate;
 222         swt->stats = table_hash_stats;
 223
 224         crc32_init(&th->crc32, polynomial);
 225         atomic_set(&th->n_flows, 0);
 226
 227         return swt;
 228 }
 229
 230 /* Double-hashing table. */
 231
 232 struct sw_table_hash2 {
 233         struct sw_table swt;
 234         struct sw_table *subtable[2];
 235 };
 236
 237 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 238                                                                                   const struct sw_flow_key *key)
 239 {
 240         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 241         int i;
 242
 243         for (i = 0; i < 2; i++) {
 244                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 245                 if (flow && !memcmp(&flow->key, key, sizeof *key))
 246                         return flow;
 247         }
 248         return NULL;
 249 }
 250
 251 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 252 {
 253         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 254
 255         if (table_hash_insert(t2->subtable[0], flow))
 256                 return 1;
 257         return table_hash_insert(t2->subtable[1], flow);
 258 }
 259
 260 static int table_hash2_delete(struct sw_table *swt,
 261                                                           const struct sw_flow_key *key,
 262                                                           uint16_t priority, int strict)
 263 {
 264         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 265         return (table_hash_delete(t2->subtable[0], key, priority, strict)
 266                         + table_hash_delete(t2->subtable[1], key, priority, strict));
 267 }
 268
 269 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 270 {
 271         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 272         return (table_hash_timeout(dp, t2->subtable[0])
 273                         + table_hash_timeout(dp, t2->subtable[1]));
 274 }
 275
 276 static void table_hash2_destroy(struct sw_table *swt)
 277 {
 278         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 279         table_hash_destroy(t2->subtable[0]);
 280         table_hash_destroy(t2->subtable[1]);
 281         kfree(t2);
 282 }
 283
 284 static int table_hash2_iterate(struct sw_table *swt,
 285                                const struct sw_flow_key *key,
 286                                struct sw_table_position *position,
 287                                int (*callback)(struct sw_flow *, void *),
 288                                void *private)
 289 {
 290         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 291         int i;
 292
 293         for (i = position->private[1]; i < 2; i++) {
 294                 int error = table_hash_iterate(t2->subtable[i], key, position,
 295                                                callback, private);
 296                 if (error) {
 297                         return error;
 298                 }
 299                 position->private[0] = 0;
 300                 position->private[1]++;
 301         }
 302         return 0;
 303 }
 304
 305 static void table_hash2_stats(struct sw_table *swt,
 306                                  struct sw_table_stats *stats)
 307 {
 308         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 309         struct sw_table_stats substats[2];
 310         int i;
 311
 312         for (i = 0; i < 2; i++)
 313                 table_hash_stats(t2->subtable[i], &substats[i]);
 314         stats->name = "hash2";
 315         stats->n_flows = substats[0].n_flows + substats[1].n_flows;
 316         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 317 }
 318
 319 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 320                                                                         unsigned int poly1, unsigned int buckets1)
 321
 322 {
 323         struct sw_table_hash2 *t2;
 324         struct sw_table *swt;
 325
 326         t2 = kmalloc(sizeof *t2, GFP_KERNEL);
 327         if (t2 == NULL)
 328                 return NULL;
 329
 330         t2->subtable[0] = table_hash_create(poly0, buckets0);
 331         if (t2->subtable[0] == NULL)
 332                 goto out_free_t2;
 333
 334         t2->subtable[1] = table_hash_create(poly1, buckets1);
 335         if (t2->subtable[1] == NULL)
 336                 goto out_free_subtable0;
 337
 338         swt = &t2->swt;
 339         swt->lookup = table_hash2_lookup;
 340         swt->insert = table_hash2_insert;
 341         swt->delete = table_hash2_delete;
 342         swt->timeout = table_hash2_timeout;
 343         swt->destroy = table_hash2_destroy;
 344         swt->iterate = table_hash2_iterate;
 345         swt->stats = table_hash2_stats;
 346
 347         return swt;
 348
 349 out_free_subtable0:
 350         table_hash_destroy(t2->subtable[0]);
 351 out_free_t2:
 352         kfree(t2);
 353         return NULL;
 354 }
 355
 356 /* From fs/xfs/linux-2.4/kmem.c. */
 357
 358 static void *
 359 kmem_alloc(size_t size)
 360 {
 361         void *ptr;
 362
 363 #ifdef KMALLOC_MAX_SIZE
 364         if (size > KMALLOC_MAX_SIZE)
 365                 return NULL;
 366 #endif
 367         ptr = kmalloc(size, GFP_KERNEL);
 368         if (!ptr) {
 369                 ptr = vmalloc(size);
 370                 if (ptr)
 371                         printk("openflow: used vmalloc for %lu bytes\n",
 372                                         (unsigned long)size);
 373         }
 374         return ptr;
 375 }
 376
 377 static void *
 378 kmem_zalloc(size_t size)
 379 {
 380         void *ptr = kmem_alloc(size);
 381         if (ptr)
 382                 memset(ptr, 0, size);
 383         return ptr;
 384 }
 385
 386 static void
 387 kmem_free(void *ptr, size_t size)
 388 {
 389         if (((unsigned long)ptr < VMALLOC_START) ||
 390                 ((unsigned long)ptr >= VMALLOC_END)) {
 391                 kfree(ptr);
 392         } else {
 393                 vfree(ptr);
 394         }
 395 }