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         spinlock_t lock;
  25         struct crc32 crc32;
  26         atomic_t n_flows;
  27         unsigned int bucket_mask; /* Number of buckets minus 1. */
  28         struct sw_flow **buckets;
  29 };
  30
  31 static struct sw_flow **find_bucket(struct sw_table *swt,
  32                                                                         const struct sw_flow_key *key)
  33 {
  34         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  35         unsigned int crc = crc32_calculate(&th->crc32, key, sizeof *key);
  36         return &th->buckets[crc & th->bucket_mask];
  37 }
  38
  39 static struct sw_flow *table_hash_lookup(struct sw_table *swt,
  40                                                                                  const struct sw_flow_key *key)
  41 {
  42         struct sw_flow *flow = *find_bucket(swt, key);
  43         return flow && !memcmp(&flow->key, key, sizeof *key) ? flow : NULL;
  44 }
  45
  46 static int table_hash_insert(struct sw_table *swt, struct sw_flow *flow)
  47 {
  48         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  49         struct sw_flow **bucket;
  50         unsigned long int flags;
  51         int retval;
  52
  53         if (flow->key.wildcards != 0)
  54                 return 0;
  55
  56         spin_lock_irqsave(&th->lock, flags);
  57         bucket = find_bucket(swt, &flow->key);
  58         if (*bucket == NULL) {
  59                 atomic_inc(&th->n_flows);
  60                 rcu_assign_pointer(*bucket, flow);
  61                 retval = 1;
  62         } else {
  63                 struct sw_flow *old_flow = *bucket;
  64                 if (!memcmp(&old_flow->key, &flow->key, sizeof flow->key)
  65                                         && flow_del(old_flow)) {
  66                         rcu_assign_pointer(*bucket, flow);
  67                         flow_deferred_free(old_flow);
  68                         retval = 1;
  69                 } else {
  70                         retval = 0;
  71                 }
  72         }
  73         spin_unlock_irqrestore(&th->lock, flags);
  74         return retval;
  75 }
  76
  77 /* Caller must update n_flows. */
  78 static int do_delete(struct sw_flow **bucket, struct sw_flow *flow)
  79 {
  80         if (flow_del(flow)) {
  81                 rcu_assign_pointer(*bucket, NULL);
  82                 flow_deferred_free(flow);
  83                 return 1;
  84         }
  85         return 0;
  86 }
  87
  88 /* Returns number of deleted flows.  We can ignore the priority
  89  * argument, since all exact-match entries are the same (highest)
  90  * priority. */
  91 static int table_hash_delete(struct sw_table *swt,
  92                                                          const struct sw_flow_key *key,
  93                                                          uint16_t priority, int strict)
  94 {
  95         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  96         unsigned int count = 0;
  97
  98         if (key->wildcards == 0) {
  99                 struct sw_flow **bucket = find_bucket(swt, key);
 100                 struct sw_flow *flow = *bucket;
 101                 if (flow && !memcmp(&flow->key, key, sizeof *key))
 102                         count = do_delete(bucket, flow);
 103         } else {
 104                 unsigned int i;
 105
 106                 for (i = 0; i <= th->bucket_mask; i++) {
 107                         struct sw_flow **bucket = &th->buckets[i];
 108                         struct sw_flow *flow = *bucket;
 109                         if (flow && flow_del_matches(&flow->key, key, strict))
 110                                 count += do_delete(bucket, flow);
 111                 }
 112         }
 113         if (count)
 114                 atomic_sub(count, &th->n_flows);
 115         return count;
 116 }
 117
 118 static int table_hash_timeout(struct datapath *dp, struct sw_table *swt)
 119 {
 120         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 121         unsigned int i;
 122         int count = 0;
 123
 124         for (i = 0; i <= th->bucket_mask; i++) {
 125                 struct sw_flow **bucket = &th->buckets[i];
 126                 struct sw_flow *flow = *bucket;
 127                 if (flow && flow_timeout(flow)) {
 128                         count += do_delete(bucket, flow);
 129                         if (dp->flags & OFPC_SEND_FLOW_EXP)
 130                                 dp_send_flow_expired(dp, flow);
 131                 }
 132         }
 133
 134         if (count)
 135                 atomic_sub(count, &th->n_flows);
 136         return count;
 137 }
 138
 139 static void table_hash_destroy(struct sw_table *swt)
 140 {
 141         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 142         unsigned int i;
 143         for (i = 0; i <= th->bucket_mask; i++)
 144         if (th->buckets[i])
 145                 flow_free(th->buckets[i]);
 146         kmem_free(th->buckets, (th->bucket_mask + 1) * sizeof *th->buckets);
 147         kfree(th);
 148 }
 149
 150 static int table_hash_iterate(struct sw_table *swt,
 151                               const struct sw_flow_key *key,
 152                               struct sw_table_position *position,
 153                               int (*callback)(struct sw_flow *, void *private),
 154                               void *private)
 155 {
 156         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 157
 158         if (position->private[0] > th->bucket_mask)
 159                 return 0;
 160
 161         if (key->wildcards == 0) {
 162                 struct sw_flow *flow;
 163                 int error;
 164
 165                 flow = table_hash_lookup(swt, key);
 166                 if (!flow)
 167                         return 0;
 168
 169                 error = callback(flow, private);
 170                 if (!error)
 171                         position->private[0] = -1;
 172                 return error;
 173         } else {
 174                 int i;
 175
 176                 for (i = position->private[0]; i <= th->bucket_mask; i++) {
 177                         struct sw_flow *flow = th->buckets[i];
 178                         if (flow && flow_matches(key, &flow->key)) {
 179                                 int error = callback(flow, private);
 180                                 if (error) {
 181                                         position->private[0] = i;
 182                                         return error;
 183                                 }
 184                         }
 185                 }
 186                 return 0;
 187         }
 188 }
 189 static void table_hash_stats(struct sw_table *swt,
 190                                  struct sw_table_stats *stats)
 191 {
 192         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 193         stats->name = "hash";
 194         stats->n_flows = atomic_read(&th->n_flows);
 195         stats->max_flows = th->bucket_mask + 1;
 196 }
 197
 198 struct sw_table *table_hash_create(unsigned int polynomial,
 199                         unsigned int n_buckets)
 200 {
 201         struct sw_table_hash *th;
 202         struct sw_table *swt;
 203
 204         th = kmalloc(sizeof *th, GFP_KERNEL);
 205         if (th == NULL)
 206                 return NULL;
 207
 208         BUG_ON(n_buckets & (n_buckets - 1));
 209         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 210         if (th->buckets == NULL) {
 211                 printk("failed to allocate %u buckets\n", n_buckets);
 212                 kfree(th);
 213                 return NULL;
 214         }
 215         th->bucket_mask = n_buckets - 1;
 216
 217         swt = &th->swt;
 218         swt->lookup = table_hash_lookup;
 219         swt->insert = table_hash_insert;
 220         swt->delete = table_hash_delete;
 221         swt->timeout = table_hash_timeout;
 222         swt->destroy = table_hash_destroy;
 223         swt->iterate = table_hash_iterate;
 224         swt->stats = table_hash_stats;
 225
 226         spin_lock_init(&th->lock);
 227         crc32_init(&th->crc32, polynomial);
 228         atomic_set(&th->n_flows, 0);
 229
 230         return swt;
 231 }
 232
 233 /* Double-hashing table. */
 234
 235 struct sw_table_hash2 {
 236         struct sw_table swt;
 237         struct sw_table *subtable[2];
 238 };
 239
 240 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 241                                                                                   const struct sw_flow_key *key)
 242 {
 243         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 244         int i;
 245
 246         for (i = 0; i < 2; i++) {
 247                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 248                 if (flow && !memcmp(&flow->key, key, sizeof *key))
 249                         return flow;
 250         }
 251         return NULL;
 252 }
 253
 254 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 255 {
 256         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 257
 258         if (table_hash_insert(t2->subtable[0], flow))
 259                 return 1;
 260         return table_hash_insert(t2->subtable[1], flow);
 261 }
 262
 263 static int table_hash2_delete(struct sw_table *swt,
 264                                                           const struct sw_flow_key *key,
 265                                                           uint16_t priority, int strict)
 266 {
 267         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 268         return (table_hash_delete(t2->subtable[0], key, priority, strict)
 269                         + table_hash_delete(t2->subtable[1], key, priority, strict));
 270 }
 271
 272 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 273 {
 274         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 275         return (table_hash_timeout(dp, t2->subtable[0])
 276                         + table_hash_timeout(dp, t2->subtable[1]));
 277 }
 278
 279 static void table_hash2_destroy(struct sw_table *swt)
 280 {
 281         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 282         table_hash_destroy(t2->subtable[0]);
 283         table_hash_destroy(t2->subtable[1]);
 284         kfree(t2);
 285 }
 286
 287 static int table_hash2_iterate(struct sw_table *swt,
 288                                const struct sw_flow_key *key,
 289                                struct sw_table_position *position,
 290                                int (*callback)(struct sw_flow *, void *),
 291                                void *private)
 292 {
 293         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 294         int i;
 295
 296         for (i = position->private[1]; i < 2; i++) {
 297                 int error = table_hash_iterate(t2->subtable[i], key, position,
 298                                                callback, private);
 299                 if (error) {
 300                         return error;
 301                 }
 302                 position->private[0] = 0;
 303                 position->private[1]++;
 304         }
 305         return 0;
 306 }
 307
 308 static void table_hash2_stats(struct sw_table *swt,
 309                                  struct sw_table_stats *stats)
 310 {
 311         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 312         struct sw_table_stats substats[2];
 313         int i;
 314
 315         for (i = 0; i < 2; i++)
 316                 table_hash_stats(t2->subtable[i], &substats[i]);
 317         stats->name = "hash2";
 318         stats->n_flows = substats[0].n_flows + substats[1].n_flows;
 319         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 320 }
 321
 322 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 323                                                                         unsigned int poly1, unsigned int buckets1)
 324
 325 {
 326         struct sw_table_hash2 *t2;
 327         struct sw_table *swt;
 328
 329         t2 = kmalloc(sizeof *t2, GFP_KERNEL);
 330         if (t2 == NULL)
 331                 return NULL;
 332
 333         t2->subtable[0] = table_hash_create(poly0, buckets0);
 334         if (t2->subtable[0] == NULL)
 335                 goto out_free_t2;
 336
 337         t2->subtable[1] = table_hash_create(poly1, buckets1);
 338         if (t2->subtable[1] == NULL)
 339                 goto out_free_subtable0;
 340
 341         swt = &t2->swt;
 342         swt->lookup = table_hash2_lookup;
 343         swt->insert = table_hash2_insert;
 344         swt->delete = table_hash2_delete;
 345         swt->timeout = table_hash2_timeout;
 346         swt->destroy = table_hash2_destroy;
 347         swt->iterate = table_hash2_iterate;
 348         swt->stats = table_hash2_stats;
 349
 350         return swt;
 351
 352 out_free_subtable0:
 353         table_hash_destroy(t2->subtable[0]);
 354 out_free_t2:
 355         kfree(t2);
 356         return NULL;
 357 }
 358
 359 /* From fs/xfs/linux-2.4/kmem.c. */
 360
 361 static void *
 362 kmem_alloc(size_t size)
 363 {
 364         void *ptr;
 365
 366 #ifdef KMALLOC_MAX_SIZE
 367         if (size > KMALLOC_MAX_SIZE)
 368                 return NULL;
 369 #endif
 370         ptr = kmalloc(size, GFP_KERNEL);
 371         if (!ptr) {
 372                 ptr = vmalloc(size);
 373                 if (ptr)
 374                         printk("openflow: used vmalloc for %lu bytes\n",
 375                                         (unsigned long)size);
 376         }
 377         return ptr;
 378 }
 379
 380 static void *
 381 kmem_zalloc(size_t size)
 382 {
 383         void *ptr = kmem_alloc(size);
 384         if (ptr)
 385                 memset(ptr, 0, size);
 386         return ptr;
 387 }
 388
 389 static void
 390 kmem_free(void *ptr, size_t size)
 391 {
 392         if (((unsigned long)ptr < VMALLOC_START) ||
 393                 ((unsigned long)ptr >= VMALLOC_END)) {
 394                 kfree(ptr);
 395         } else {
 396                 vfree(ptr);
 397         }
 398 }