lib/test_rhashtable.c

   1 /*
   2  * Resizable, Scalable, Concurrent Hash Table
   3  *
   4  * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
   5  * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 /**************************************************************************
  13  * Self Test
  14  **************************************************************************/
  15
  16 #include <linux/init.h>
  17 #include <linux/jhash.h>
  18 #include <linux/kernel.h>
  19 #include <linux/kthread.h>
  20 #include <linux/module.h>
  21 #include <linux/rcupdate.h>
  22 #include <linux/rhashtable.h>
  23 #include <linux/semaphore.h>
  24 #include <linux/slab.h>
  25 #include <linux/sched.h>
  26 #include <linux/vmalloc.h>
  27
  28 #define MAX_ENTRIES     1000000
  29 #define TEST_INSERT_FAIL INT_MAX
  30
  31 static int entries = 50000;
  32 module_param(entries, int, 0);
  33 MODULE_PARM_DESC(entries, "Number of entries to add (default: 50000)");
  34
  35 static int runs = 4;
  36 module_param(runs, int, 0);
  37 MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");
  38
  39 static int max_size = 65536;
  40 module_param(max_size, int, 0);
  41 MODULE_PARM_DESC(runs, "Maximum table size (default: 65536)");
  42
  43 static bool shrinking = false;
  44 module_param(shrinking, bool, 0);
  45 MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");
  46
  47 static int size = 8;
  48 module_param(size, int, 0);
  49 MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");
  50
  51 static int tcount = 10;
  52 module_param(tcount, int, 0);
  53 MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");
  54
  55 struct test_obj {
  56         int                     value;
  57         struct rhash_head       node;
  58 };
  59
  60 struct thread_data {
  61         int id;
  62         struct task_struct *task;
  63         struct test_obj *objs;
  64 };
  65
  66 static struct test_obj array[MAX_ENTRIES];
  67
  68 static struct rhashtable_params test_rht_params = {
  69         .head_offset = offsetof(struct test_obj, node),
  70         .key_offset = offsetof(struct test_obj, value),
  71         .key_len = sizeof(int),
  72         .hashfn = jhash,
  73         .nulls_base = (3U << RHT_BASE_SHIFT),
  74 };
  75
  76 static struct semaphore prestart_sem;
  77 static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);
  78
  79 static int __init test_rht_lookup(struct rhashtable *ht)
  80 {
  81         unsigned int i;
  82
  83         for (i = 0; i < entries * 2; i++) {
  84                 struct test_obj *obj;
  85                 bool expected = !(i % 2);
  86                 u32 key = i;
  87
  88                 if (array[i / 2].value == TEST_INSERT_FAIL)
  89                         expected = false;
  90
  91                 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
  92
  93                 if (expected && !obj) {
  94                         pr_warn("Test failed: Could not find key %u\n", key);
  95                         return -ENOENT;
  96                 } else if (!expected && obj) {
  97                         pr_warn("Test failed: Unexpected entry found for key %u\n",
  98                                 key);
  99                         return -EEXIST;
 100                 } else if (expected && obj) {
 101                         if (obj->value != i) {
 102                                 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
 103                                         obj->value, i);
 104                                 return -EINVAL;
 105                         }
 106                 }
 107
 108                 cond_resched_rcu();
 109         }
 110
 111         return 0;
 112 }
 113
 114 static void test_bucket_stats(struct rhashtable *ht)
 115 {
 116         unsigned int err, total = 0, chain_len = 0;
 117         struct rhashtable_iter hti;
 118         struct rhash_head *pos;
 119
 120         err = rhashtable_walk_init(ht, &hti);
 121         if (err) {
 122                 pr_warn("Test failed: allocation error");
 123                 return;
 124         }
 125
 126         err = rhashtable_walk_start(&hti);
 127         if (err && err != -EAGAIN) {
 128                 pr_warn("Test failed: iterator failed: %d\n", err);
 129                 return;
 130         }
 131
 132         while ((pos = rhashtable_walk_next(&hti))) {
 133                 if (PTR_ERR(pos) == -EAGAIN) {
 134                         pr_info("Info: encountered resize\n");
 135                         chain_len++;
 136                         continue;
 137                 } else if (IS_ERR(pos)) {
 138                         pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
 139                                 PTR_ERR(pos));
 140                         break;
 141                 }
 142
 143                 total++;
 144         }
 145
 146         rhashtable_walk_stop(&hti);
 147         rhashtable_walk_exit(&hti);
 148
 149         pr_info("  Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
 150                 total, atomic_read(&ht->nelems), entries, chain_len);
 151
 152         if (total != atomic_read(&ht->nelems) || total != entries)
 153                 pr_warn("Test failed: Total count mismatch ^^^");
 154 }
 155
 156 static s64 __init test_rhashtable(struct rhashtable *ht)
 157 {
 158         struct test_obj *obj;
 159         int err;
 160         unsigned int i, insert_fails = 0;
 161         s64 start, end;
 162
 163         /*
 164          * Insertion Test:
 165          * Insert entries into table with all keys even numbers
 166          */
 167         pr_info("  Adding %d keys\n", entries);
 168         start = ktime_get_ns();
 169         for (i = 0; i < entries; i++) {
 170                 struct test_obj *obj = &array[i];
 171
 172                 obj->value = i * 2;
 173
 174                 err = rhashtable_insert_fast(ht, &obj->node, test_rht_params);
 175                 if (err == -ENOMEM || err == -EBUSY) {
 176                         /* Mark failed inserts but continue */
 177                         obj->value = TEST_INSERT_FAIL;
 178                         insert_fails++;
 179                 } else if (err) {
 180                         return err;
 181                 }
 182
 183                 cond_resched();
 184         }
 185
 186         if (insert_fails)
 187                 pr_info("  %u insertions failed due to memory pressure\n",
 188                         insert_fails);
 189
 190         test_bucket_stats(ht);
 191         rcu_read_lock();
 192         test_rht_lookup(ht);
 193         rcu_read_unlock();
 194
 195         test_bucket_stats(ht);
 196
 197         pr_info("  Deleting %d keys\n", entries);
 198         for (i = 0; i < entries; i++) {
 199                 u32 key = i * 2;
 200
 201                 if (array[i].value != TEST_INSERT_FAIL) {
 202                         obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 203                         BUG_ON(!obj);
 204
 205                         rhashtable_remove_fast(ht, &obj->node, test_rht_params);
 206                 }
 207
 208                 cond_resched();
 209         }
 210
 211         end = ktime_get_ns();
 212         pr_info("  Duration of test: %lld ns\n", end - start);
 213
 214         return end - start;
 215 }
 216
 217 static struct rhashtable ht;
 218
 219 static int thread_lookup_test(struct thread_data *tdata)
 220 {
 221         int i, err = 0;
 222
 223         for (i = 0; i < entries; i++) {
 224                 struct test_obj *obj;
 225                 int key = (tdata->id << 16) | i;
 226
 227                 obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
 228                 if (obj && (tdata->objs[i].value == TEST_INSERT_FAIL)) {
 229                         pr_err("  found unexpected object %d\n", key);
 230                         err++;
 231                 } else if (!obj && (tdata->objs[i].value != TEST_INSERT_FAIL)) {
 232                         pr_err("  object %d not found!\n", key);
 233                         err++;
 234                 } else if (obj && (obj->value != key)) {
 235                         pr_err("  wrong object returned (got %d, expected %d)\n",
 236                                obj->value, key);
 237                         err++;
 238                 }
 239         }
 240         return err;
 241 }
 242
 243 static int threadfunc(void *data)
 244 {
 245         int i, step, err = 0, insert_fails = 0;
 246         struct thread_data *tdata = data;
 247
 248         up(&prestart_sem);
 249         if (down_interruptible(&startup_sem))
 250                 pr_err("  thread[%d]: down_interruptible failed\n", tdata->id);
 251
 252         for (i = 0; i < entries; i++) {
 253                 tdata->objs[i].value = (tdata->id << 16) | i;
 254                 err = rhashtable_insert_fast(&ht, &tdata->objs[i].node,
 255                                              test_rht_params);
 256                 if (err == -ENOMEM || err == -EBUSY) {
 257                         tdata->objs[i].value = TEST_INSERT_FAIL;
 258                         insert_fails++;
 259                 } else if (err) {
 260                         pr_err("  thread[%d]: rhashtable_insert_fast failed\n",
 261                                tdata->id);
 262                         goto out;
 263                 }
 264         }
 265         if (insert_fails)
 266                 pr_info("  thread[%d]: %d insert failures\n",
 267                         tdata->id, insert_fails);
 268
 269         err = thread_lookup_test(tdata);
 270         if (err) {
 271                 pr_err("  thread[%d]: rhashtable_lookup_test failed\n",
 272                        tdata->id);
 273                 goto out;
 274         }
 275
 276         for (step = 10; step > 0; step--) {
 277                 for (i = 0; i < entries; i += step) {
 278                         if (tdata->objs[i].value == TEST_INSERT_FAIL)
 279                                 continue;
 280                         err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
 281                                                      test_rht_params);
 282                         if (err) {
 283                                 pr_err("  thread[%d]: rhashtable_remove_fast failed\n",
 284                                        tdata->id);
 285                                 goto out;
 286                         }
 287                         tdata->objs[i].value = TEST_INSERT_FAIL;
 288                 }
 289                 err = thread_lookup_test(tdata);
 290                 if (err) {
 291                         pr_err("  thread[%d]: rhashtable_lookup_test (2) failed\n",
 292                                tdata->id);
 293                         goto out;
 294                 }
 295         }
 296 out:
 297         while (!kthread_should_stop()) {
 298                 set_current_state(TASK_INTERRUPTIBLE);
 299                 schedule();
 300         }
 301         return err;
 302 }
 303
 304 static int __init test_rht_init(void)
 305 {
 306         int i, err, started_threads = 0, failed_threads = 0;
 307         u64 total_time = 0;
 308         struct thread_data *tdata;
 309         struct test_obj *objs;
 310
 311         entries = min(entries, MAX_ENTRIES);
 312
 313         test_rht_params.automatic_shrinking = shrinking;
 314         test_rht_params.max_size = max_size;
 315         test_rht_params.nelem_hint = size;
 316
 317         pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
 318                 size, max_size, shrinking);
 319
 320         for (i = 0; i < runs; i++) {
 321                 s64 time;
 322
 323                 pr_info("Test %02d:\n", i);
 324                 memset(&array, 0, sizeof(array));
 325                 err = rhashtable_init(&ht, &test_rht_params);
 326                 if (err < 0) {
 327                         pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 328                                 err);
 329                         continue;
 330                 }
 331
 332                 time = test_rhashtable(&ht);
 333                 rhashtable_destroy(&ht);
 334                 if (time < 0) {
 335                         pr_warn("Test failed: return code %lld\n", time);
 336                         return -EINVAL;
 337                 }
 338
 339                 total_time += time;
 340         }
 341
 342         do_div(total_time, runs);
 343         pr_info("Average test time: %llu\n", total_time);
 344
 345         if (!tcount)
 346                 return 0;
 347
 348         pr_info("Testing concurrent rhashtable access from %d threads\n",
 349                 tcount);
 350         sema_init(&prestart_sem, 1 - tcount);
 351         tdata = vzalloc(tcount * sizeof(struct thread_data));
 352         if (!tdata)
 353                 return -ENOMEM;
 354         objs  = vzalloc(tcount * entries * sizeof(struct test_obj));
 355         if (!objs) {
 356                 vfree(tdata);
 357                 return -ENOMEM;
 358         }
 359
 360         err = rhashtable_init(&ht, &test_rht_params);
 361         if (err < 0) {
 362                 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 363                         err);
 364                 vfree(tdata);
 365                 vfree(objs);
 366                 return -EINVAL;
 367         }
 368         for (i = 0; i < tcount; i++) {
 369                 tdata[i].id = i;
 370                 tdata[i].objs = objs + i * entries;
 371                 tdata[i].task = kthread_run(threadfunc, &tdata[i],
 372                                             "rhashtable_thrad[%d]", i);
 373                 if (IS_ERR(tdata[i].task))
 374                         pr_err(" kthread_run failed for thread %d\n", i);
 375                 else
 376                         started_threads++;
 377         }
 378         if (down_interruptible(&prestart_sem))
 379                 pr_err("  down interruptible failed\n");
 380         for (i = 0; i < tcount; i++)
 381                 up(&startup_sem);
 382         for (i = 0; i < tcount; i++) {
 383                 if (IS_ERR(tdata[i].task))
 384                         continue;
 385                 if ((err = kthread_stop(tdata[i].task))) {
 386                         pr_warn("Test failed: thread %d returned: %d\n",
 387                                 i, err);
 388                         failed_threads++;
 389                 }
 390         }
 391         pr_info("Started %d threads, %d failed\n",
 392                 started_threads, failed_threads);
 393         rhashtable_destroy(&ht);
 394         vfree(tdata);
 395         vfree(objs);
 396         return 0;
 397 }
 398
 399 static void __exit test_rht_exit(void)
 400 {
 401 }
 402
 403 module_init(test_rht_init);
 404 module_exit(test_rht_exit);
 405
 406 MODULE_LICENSE("GPL v2");