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