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         mutex_lock(&dp_mutex);
 125         for (i = 0; i <= th->bucket_mask; i++) {
 126                 struct sw_flow **bucket = &th->buckets[i];
 127                 struct sw_flow *flow = *bucket;
 128                 if (flow && flow_timeout(flow)) {
 129                         count += do_delete(bucket, flow);
 130                         if (dp->flags & OFPC_SEND_FLOW_EXP)
 131                                 dp_send_flow_expired(dp, flow);
 132                 }
 133         }
 134         mutex_unlock(&dp_mutex);
 135
 136         if (count)
 137                 atomic_sub(count, &th->n_flows);
 138         return count;
 139 }
 140
 141 static void table_hash_destroy(struct sw_table *swt)
 142 {
 143         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 144         unsigned int i;
 145         for (i = 0; i <= th->bucket_mask; i++)
 146         if (th->buckets[i])
 147                 flow_free(th->buckets[i]);
 148         kmem_free(th->buckets, (th->bucket_mask + 1) * sizeof *th->buckets);
 149         kfree(th);
 150 }
 151
 152 static int table_hash_iterate(struct sw_table *swt,
 153                               const struct sw_flow_key *key,
 154                               struct sw_table_position *position,
 155                               int (*callback)(struct sw_flow *, void *private),
 156                               void *private)
 157 {
 158         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 159
 160         if (position->private[0] > th->bucket_mask)
 161                 return 0;
 162
 163         if (key->wildcards == 0) {
 164                 struct sw_flow *flow;
 165                 int error;
 166
 167                 flow = table_hash_lookup(swt, key);
 168                 if (!flow)
 169                         return 0;
 170
 171                 error = callback(flow, private);
 172                 if (!error)
 173                         position->private[0] = -1;
 174                 return error;
 175         } else {
 176                 int i;
 177
 178                 for (i = position->private[0]; i <= th->bucket_mask; i++) {
 179                         struct sw_flow *flow = th->buckets[i];
 180                         if (flow && flow_matches(key, &flow->key)) {
 181                                 int error = callback(flow, private);
 182                                 if (error) {
 183                                         position->private[0] = i;
 184                                         return error;
 185                                 }
 186                         }
 187                 }
 188                 return 0;
 189         }
 190 }
 191 static void table_hash_stats(struct sw_table *swt,
 192                                  struct sw_table_stats *stats)
 193 {
 194         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 195         stats->name = "hash";
 196         stats->n_flows = atomic_read(&th->n_flows);
 197         stats->max_flows = th->bucket_mask + 1;
 198 }
 199
 200 struct sw_table *table_hash_create(unsigned int polynomial,
 201                         unsigned int n_buckets)
 202 {
 203         struct sw_table_hash *th;
 204         struct sw_table *swt;
 205
 206         th = kmalloc(sizeof *th, GFP_KERNEL);
 207         if (th == NULL)
 208                 return NULL;
 209
 210         BUG_ON(n_buckets & (n_buckets - 1));
 211         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 212         if (th->buckets == NULL) {
 213                 printk("failed to allocate %u buckets\n", n_buckets);
 214                 kfree(th);
 215                 return NULL;
 216         }
 217         th->bucket_mask = n_buckets - 1;
 218
 219         swt = &th->swt;
 220         swt->lookup = table_hash_lookup;
 221         swt->insert = table_hash_insert;
 222         swt->delete = table_hash_delete;
 223         swt->timeout = table_hash_timeout;
 224         swt->destroy = table_hash_destroy;
 225         swt->iterate = table_hash_iterate;
 226         swt->stats = table_hash_stats;
 227
 228         spin_lock_init(&th->lock);
 229         crc32_init(&th->crc32, polynomial);
 230         atomic_set(&th->n_flows, 0);
 231
 232         return swt;
 233 }
 234
 235 /* Double-hashing table. */
 236
 237 struct sw_table_hash2 {
 238         struct sw_table swt;
 239         struct sw_table *subtable[2];
 240 };
 241
 242 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 243                                                                                   const struct sw_flow_key *key)
 244 {
 245         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 246         int i;
 247
 248         for (i = 0; i < 2; i++) {
 249                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 250                 if (flow && !memcmp(&flow->key, key, sizeof *key))
 251                         return flow;
 252         }
 253         return NULL;
 254 }
 255
 256 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 257 {
 258         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 259
 260         if (table_hash_insert(t2->subtable[0], flow))
 261                 return 1;
 262         return table_hash_insert(t2->subtable[1], flow);
 263 }
 264
 265 static int table_hash2_delete(struct sw_table *swt,
 266                                                           const struct sw_flow_key *key,
 267                                                           uint16_t priority, int strict)
 268 {
 269         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 270         return (table_hash_delete(t2->subtable[0], key, priority, strict)
 271                         + table_hash_delete(t2->subtable[1], key, priority, strict));
 272 }
 273
 274 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 275 {
 276         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 277         return (table_hash_timeout(dp, t2->subtable[0])
 278                         + table_hash_timeout(dp, t2->subtable[1]));
 279 }
 280
 281 static void table_hash2_destroy(struct sw_table *swt)
 282 {
 283         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 284         table_hash_destroy(t2->subtable[0]);
 285         table_hash_destroy(t2->subtable[1]);
 286         kfree(t2);
 287 }
 288
 289 static int table_hash2_iterate(struct sw_table *swt,
 290                                const struct sw_flow_key *key,
 291                                struct sw_table_position *position,
 292                                int (*callback)(struct sw_flow *, void *),
 293                                void *private)
 294 {
 295         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 296         int i;
 297
 298         for (i = position->private[1]; i < 2; i++) {
 299                 int error = table_hash_iterate(t2->subtable[i], key, position,
 300                                                callback, private);
 301                 if (error) {
 302                         return error;
 303                 }
 304                 position->private[0] = 0;
 305                 position->private[1]++;
 306         }
 307         return 0;
 308 }
 309
 310 static void table_hash2_stats(struct sw_table *swt,
 311                                  struct sw_table_stats *stats)
 312 {
 313         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 314         struct sw_table_stats substats[2];
 315         int i;
 316
 317         for (i = 0; i < 2; i++)
 318                 table_hash_stats(t2->subtable[i], &substats[i]);
 319         stats->name = "hash2";
 320         stats->n_flows = substats[0].n_flows + substats[1].n_flows;
 321         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 322 }
 323
 324 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 325                                                                         unsigned int poly1, unsigned int buckets1)
 326
 327 {
 328         struct sw_table_hash2 *t2;
 329         struct sw_table *swt;
 330
 331         t2 = kmalloc(sizeof *t2, GFP_KERNEL);
 332         if (t2 == NULL)
 333                 return NULL;
 334
 335         t2->subtable[0] = table_hash_create(poly0, buckets0);
 336         if (t2->subtable[0] == NULL)
 337                 goto out_free_t2;
 338
 339         t2->subtable[1] = table_hash_create(poly1, buckets1);
 340         if (t2->subtable[1] == NULL)
 341                 goto out_free_subtable0;
 342
 343         swt = &t2->swt;
 344         swt->lookup = table_hash2_lookup;
 345         swt->insert = table_hash2_insert;
 346         swt->delete = table_hash2_delete;
 347         swt->timeout = table_hash2_timeout;
 348         swt->destroy = table_hash2_destroy;
 349         swt->iterate = table_hash2_iterate;
 350         swt->stats = table_hash2_stats;
 351
 352         return swt;
 353
 354 out_free_subtable0:
 355         table_hash_destroy(t2->subtable[0]);
 356 out_free_t2:
 357         kfree(t2);
 358         return NULL;
 359 }
 360
 361 /* From fs/xfs/linux-2.4/kmem.c. */
 362
 363 static void *
 364 kmem_alloc(size_t size)
 365 {
 366         void *ptr;
 367
 368 #ifdef KMALLOC_MAX_SIZE
 369         if (size > KMALLOC_MAX_SIZE)
 370                 return NULL;
 371 #endif
 372         ptr = kmalloc(size, GFP_KERNEL);
 373         if (!ptr) {
 374                 ptr = vmalloc(size);
 375                 if (ptr)
 376                         printk("openflow: used vmalloc for %lu bytes\n",
 377                                         (unsigned long)size);
 378         }
 379         return ptr;
 380 }
 381
 382 static void *
 383 kmem_zalloc(size_t size)
 384 {
 385         void *ptr = kmem_alloc(size);
 386         if (ptr)
 387                 memset(ptr, 0, size);
 388         return ptr;
 389 }
 390
 391 static void
 392 kmem_free(void *ptr, size_t size)
 393 {
 394         if (((unsigned long)ptr < VMALLOC_START) ||
 395                 ((unsigned long)ptr >= VMALLOC_END)) {
 396                 kfree(ptr);
 397         } else {
 398                 vfree(ptr);
 399         }
 400 }