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/random.h>
  27 #include <linux/vmalloc.h>
  28
  29 #define MAX_ENTRIES     1000000
  30 #define TEST_INSERT_FAIL INT_MAX
  31
  32 static int parm_entries = 50000;
  33 module_param(parm_entries, int, 0);
  34 MODULE_PARM_DESC(parm_entries, "Number of entries to add (default: 50000)");
  35
  36 static int runs = 4;
  37 module_param(runs, int, 0);
  38 MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");
  39
  40 static int max_size = 0;
  41 module_param(max_size, int, 0);
  42 MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");
  43
  44 static bool shrinking = false;
  45 module_param(shrinking, bool, 0);
  46 MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");
  47
  48 static int size = 8;
  49 module_param(size, int, 0);
  50 MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");
  51
  52 static int tcount = 10;
  53 module_param(tcount, int, 0);
  54 MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");
  55
  56 static bool enomem_retry = false;
  57 module_param(enomem_retry, bool, 0);
  58 MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");
  59
  60 struct test_obj_val {
  61         int     id;
  62         int     tid;
  63 };
  64
  65 struct test_obj {
  66         struct test_obj_val     value;
  67         struct rhash_head       node;
  68 };
  69
  70 struct test_obj_rhl {
  71         struct test_obj_val     value;
  72         struct rhlist_head      list_node;
  73 };
  74
  75 struct thread_data {
  76         unsigned int entries;
  77         int id;
  78         struct task_struct *task;
  79         struct test_obj *objs;
  80 };
  81
  82 static struct rhashtable_params test_rht_params = {
  83         .head_offset = offsetof(struct test_obj, node),
  84         .key_offset = offsetof(struct test_obj, value),
  85         .key_len = sizeof(struct test_obj_val),
  86         .hashfn = jhash,
  87         .nulls_base = (3U << RHT_BASE_SHIFT),
  88 };
  89
  90 static struct semaphore prestart_sem;
  91 static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);
  92
  93 static int insert_retry(struct rhashtable *ht, struct test_obj *obj,
  94                         const struct rhashtable_params params)
  95 {
  96         int err, retries = -1, enomem_retries = 0;
  97
  98         do {
  99                 retries++;
 100                 cond_resched();
 101                 err = rhashtable_insert_fast(ht, &obj->node, params);
 102                 if (err == -ENOMEM && enomem_retry) {
 103                         enomem_retries++;
 104                         err = -EBUSY;
 105                 }
 106         } while (err == -EBUSY);
 107
 108         if (enomem_retries)
 109                 pr_info(" %u insertions retried after -ENOMEM\n",
 110                         enomem_retries);
 111
 112         return err ? : retries;
 113 }
 114
 115 static int __init test_rht_lookup(struct rhashtable *ht, struct test_obj *array,
 116                                   unsigned int entries)
 117 {
 118         unsigned int i;
 119
 120         for (i = 0; i < entries; i++) {
 121                 struct test_obj *obj;
 122                 bool expected = !(i % 2);
 123                 struct test_obj_val key = {
 124                         .id = i,
 125                 };
 126
 127                 if (array[i / 2].value.id == TEST_INSERT_FAIL)
 128                         expected = false;
 129
 130                 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 131
 132                 if (expected && !obj) {
 133                         pr_warn("Test failed: Could not find key %u\n", key.id);
 134                         return -ENOENT;
 135                 } else if (!expected && obj) {
 136                         pr_warn("Test failed: Unexpected entry found for key %u\n",
 137                                 key.id);
 138                         return -EEXIST;
 139                 } else if (expected && obj) {
 140                         if (obj->value.id != i) {
 141                                 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
 142                                         obj->value.id, i);
 143                                 return -EINVAL;
 144                         }
 145                 }
 146
 147                 cond_resched_rcu();
 148         }
 149
 150         return 0;
 151 }
 152
 153 static void test_bucket_stats(struct rhashtable *ht, unsigned int entries)
 154 {
 155         unsigned int err, total = 0, chain_len = 0;
 156         struct rhashtable_iter hti;
 157         struct rhash_head *pos;
 158
 159         err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
 160         if (err) {
 161                 pr_warn("Test failed: allocation error");
 162                 return;
 163         }
 164
 165         err = rhashtable_walk_start(&hti);
 166         if (err && err != -EAGAIN) {
 167                 pr_warn("Test failed: iterator failed: %d\n", err);
 168                 return;
 169         }
 170
 171         while ((pos = rhashtable_walk_next(&hti))) {
 172                 if (PTR_ERR(pos) == -EAGAIN) {
 173                         pr_info("Info: encountered resize\n");
 174                         chain_len++;
 175                         continue;
 176                 } else if (IS_ERR(pos)) {
 177                         pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
 178                                 PTR_ERR(pos));
 179                         break;
 180                 }
 181
 182                 total++;
 183         }
 184
 185         rhashtable_walk_stop(&hti);
 186         rhashtable_walk_exit(&hti);
 187
 188         pr_info("  Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
 189                 total, atomic_read(&ht->nelems), entries, chain_len);
 190
 191         if (total != atomic_read(&ht->nelems) || total != entries)
 192                 pr_warn("Test failed: Total count mismatch ^^^");
 193 }
 194
 195 static s64 __init test_rhashtable(struct rhashtable *ht, struct test_obj *array,
 196                                   unsigned int entries)
 197 {
 198         struct test_obj *obj;
 199         int err;
 200         unsigned int i, insert_retries = 0;
 201         s64 start, end;
 202
 203         /*
 204          * Insertion Test:
 205          * Insert entries into table with all keys even numbers
 206          */
 207         pr_info("  Adding %d keys\n", entries);
 208         start = ktime_get_ns();
 209         for (i = 0; i < entries; i++) {
 210                 struct test_obj *obj = &array[i];
 211
 212                 obj->value.id = i * 2;
 213                 err = insert_retry(ht, obj, test_rht_params);
 214                 if (err > 0)
 215                         insert_retries += err;
 216                 else if (err)
 217                         return err;
 218         }
 219
 220         if (insert_retries)
 221                 pr_info("  %u insertions retried due to memory pressure\n",
 222                         insert_retries);
 223
 224         test_bucket_stats(ht, entries);
 225         rcu_read_lock();
 226         test_rht_lookup(ht, array, entries);
 227         rcu_read_unlock();
 228
 229         test_bucket_stats(ht, entries);
 230
 231         pr_info("  Deleting %d keys\n", entries);
 232         for (i = 0; i < entries; i++) {
 233                 struct test_obj_val key = {
 234                         .id = i * 2,
 235                 };
 236
 237                 if (array[i].value.id != TEST_INSERT_FAIL) {
 238                         obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 239                         BUG_ON(!obj);
 240
 241                         rhashtable_remove_fast(ht, &obj->node, test_rht_params);
 242                 }
 243
 244                 cond_resched();
 245         }
 246
 247         end = ktime_get_ns();
 248         pr_info("  Duration of test: %lld ns\n", end - start);
 249
 250         return end - start;
 251 }
 252
 253 static struct rhashtable ht;
 254 static struct rhltable rhlt;
 255
 256 static int __init test_rhltable(unsigned int entries)
 257 {
 258         struct test_obj_rhl *rhl_test_objects;
 259         unsigned long *obj_in_table;
 260         unsigned int i, j, k;
 261         int ret, err;
 262
 263         if (entries == 0)
 264                 entries = 1;
 265
 266         rhl_test_objects = vzalloc(sizeof(*rhl_test_objects) * entries);
 267         if (!rhl_test_objects)
 268                 return -ENOMEM;
 269
 270         ret = -ENOMEM;
 271         obj_in_table = vzalloc(BITS_TO_LONGS(entries) * sizeof(unsigned long));
 272         if (!obj_in_table)
 273                 goto out_free;
 274
 275         /* nulls_base not supported in rhlist interface */
 276         test_rht_params.nulls_base = 0;
 277         err = rhltable_init(&rhlt, &test_rht_params);
 278         if (WARN_ON(err))
 279                 goto out_free;
 280
 281         k = prandom_u32();
 282         ret = 0;
 283         for (i = 0; i < entries; i++) {
 284                 rhl_test_objects[i].value.id = k;
 285                 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
 286                                       test_rht_params);
 287                 if (WARN(err, "error %d on element %d\n", err, i))
 288                         break;
 289                 if (err == 0)
 290                         set_bit(i, obj_in_table);
 291         }
 292
 293         if (err)
 294                 ret = err;
 295
 296         pr_info("test %d add/delete pairs into rhlist\n", entries);
 297         for (i = 0; i < entries; i++) {
 298                 struct rhlist_head *h, *pos;
 299                 struct test_obj_rhl *obj;
 300                 struct test_obj_val key = {
 301                         .id = k,
 302                 };
 303                 bool found;
 304
 305                 rcu_read_lock();
 306                 h = rhltable_lookup(&rhlt, &key, test_rht_params);
 307                 if (WARN(!h, "key not found during iteration %d of %d", i, entries)) {
 308                         rcu_read_unlock();
 309                         break;
 310                 }
 311
 312                 if (i) {
 313                         j = i - 1;
 314                         rhl_for_each_entry_rcu(obj, pos, h, list_node) {
 315                                 if (WARN(pos == &rhl_test_objects[j].list_node, "old element found, should be gone"))
 316                                         break;
 317                         }
 318                 }
 319
 320                 cond_resched_rcu();
 321
 322                 found = false;
 323
 324                 rhl_for_each_entry_rcu(obj, pos, h, list_node) {
 325                         if (pos == &rhl_test_objects[i].list_node) {
 326                                 found = true;
 327                                 break;
 328                         }
 329                 }
 330
 331                 rcu_read_unlock();
 332
 333                 if (WARN(!found, "element %d not found", i))
 334                         break;
 335
 336                 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
 337                 WARN(err, "rhltable_remove: err %d for iteration %d\n", err, i);
 338                 if (err == 0)
 339                         clear_bit(i, obj_in_table);
 340         }
 341
 342         if (ret == 0 && err)
 343                 ret = err;
 344
 345         for (i = 0; i < entries; i++) {
 346                 WARN(test_bit(i, obj_in_table), "elem %d allegedly still present", i);
 347
 348                 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
 349                                       test_rht_params);
 350                 if (WARN(err, "error %d on element %d\n", err, i))
 351                         break;
 352                 if (err == 0)
 353                         set_bit(i, obj_in_table);
 354         }
 355
 356         pr_info("test %d random rhlist add/delete operations\n", entries);
 357         for (j = 0; j < entries; j++) {
 358                 u32 i = prandom_u32_max(entries);
 359                 u32 prand = prandom_u32();
 360
 361                 cond_resched();
 362
 363                 if (prand == 0)
 364                         prand = prandom_u32();
 365
 366                 if (prand & 1) {
 367                         prand >>= 1;
 368                         continue;
 369                 }
 370
 371                 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
 372                 if (test_bit(i, obj_in_table)) {
 373                         clear_bit(i, obj_in_table);
 374                         if (WARN(err, "cannot remove element at slot %d", i))
 375                                 continue;
 376                 } else {
 377                         if (WARN(err != -ENOENT, "removed non-existant element %d, error %d not %d",
 378                              i, err, -ENOENT))
 379                                 continue;
 380                 }
 381
 382                 if (prand & 1) {
 383                         prand >>= 1;
 384                         continue;
 385                 }
 386
 387                 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
 388                 if (err == 0) {
 389                         if (WARN(test_and_set_bit(i, obj_in_table), "succeeded to insert same object %d", i))
 390                                 continue;
 391                 } else {
 392                         if (WARN(!test_bit(i, obj_in_table), "failed to insert object %d", i))
 393                                 continue;
 394                 }
 395
 396                 if (prand & 1) {
 397                         prand >>= 1;
 398                         continue;
 399                 }
 400
 401                 i = prandom_u32_max(entries);
 402                 if (test_bit(i, obj_in_table)) {
 403                         err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
 404                         WARN(err, "cannot remove element at slot %d", i);
 405                         if (err == 0)
 406                                 clear_bit(i, obj_in_table);
 407                 } else {
 408                         err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
 409                         WARN(err, "failed to insert object %d", i);
 410                         if (err == 0)
 411                                 set_bit(i, obj_in_table);
 412                 }
 413         }
 414
 415         for (i = 0; i < entries; i++) {
 416                 cond_resched();
 417                 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
 418                 if (test_bit(i, obj_in_table)) {
 419                         if (WARN(err, "cannot remove element at slot %d", i))
 420                                 continue;
 421                 } else {
 422                         if (WARN(err != -ENOENT, "removed non-existant element, error %d not %d",
 423                                  err, -ENOENT))
 424                         continue;
 425                 }
 426         }
 427
 428         rhltable_destroy(&rhlt);
 429 out_free:
 430         vfree(rhl_test_objects);
 431         vfree(obj_in_table);
 432         return ret;
 433 }
 434
 435 static int __init test_rhashtable_max(struct test_obj *array,
 436                                       unsigned int entries)
 437 {
 438         unsigned int i, insert_retries = 0;
 439         int err;
 440
 441         test_rht_params.max_size = roundup_pow_of_two(entries / 8);
 442         err = rhashtable_init(&ht, &test_rht_params);
 443         if (err)
 444                 return err;
 445
 446         for (i = 0; i < ht.max_elems; i++) {
 447                 struct test_obj *obj = &array[i];
 448
 449                 obj->value.id = i * 2;
 450                 err = insert_retry(&ht, obj, test_rht_params);
 451                 if (err > 0)
 452                         insert_retries += err;
 453                 else if (err)
 454                         return err;
 455         }
 456
 457         err = insert_retry(&ht, &array[ht.max_elems], test_rht_params);
 458         if (err == -E2BIG) {
 459                 err = 0;
 460         } else {
 461                 pr_info("insert element %u should have failed with %d, got %d\n",
 462                                 ht.max_elems, -E2BIG, err);
 463                 if (err == 0)
 464                         err = -1;
 465         }
 466
 467         rhashtable_destroy(&ht);
 468
 469         return err;
 470 }
 471
 472 static int thread_lookup_test(struct thread_data *tdata)
 473 {
 474         unsigned int entries = tdata->entries;
 475         int i, err = 0;
 476
 477         for (i = 0; i < entries; i++) {
 478                 struct test_obj *obj;
 479                 struct test_obj_val key = {
 480                         .id = i,
 481                         .tid = tdata->id,
 482                 };
 483
 484                 obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
 485                 if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
 486                         pr_err("  found unexpected object %d-%d\n", key.tid, key.id);
 487                         err++;
 488                 } else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
 489                         pr_err("  object %d-%d not found!\n", key.tid, key.id);
 490                         err++;
 491                 } else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
 492                         pr_err("  wrong object returned (got %d-%d, expected %d-%d)\n",
 493                                obj->value.tid, obj->value.id, key.tid, key.id);
 494                         err++;
 495                 }
 496
 497                 cond_resched();
 498         }
 499         return err;
 500 }
 501
 502 static int threadfunc(void *data)
 503 {
 504         int i, step, err = 0, insert_retries = 0;
 505         struct thread_data *tdata = data;
 506
 507         up(&prestart_sem);
 508         if (down_interruptible(&startup_sem))
 509                 pr_err("  thread[%d]: down_interruptible failed\n", tdata->id);
 510
 511         for (i = 0; i < tdata->entries; i++) {
 512                 tdata->objs[i].value.id = i;
 513                 tdata->objs[i].value.tid = tdata->id;
 514                 err = insert_retry(&ht, &tdata->objs[i], test_rht_params);
 515                 if (err > 0) {
 516                         insert_retries += err;
 517                 } else if (err) {
 518                         pr_err("  thread[%d]: rhashtable_insert_fast failed\n",
 519                                tdata->id);
 520                         goto out;
 521                 }
 522         }
 523         if (insert_retries)
 524                 pr_info("  thread[%d]: %u insertions retried due to memory pressure\n",
 525                         tdata->id, insert_retries);
 526
 527         err = thread_lookup_test(tdata);
 528         if (err) {
 529                 pr_err("  thread[%d]: rhashtable_lookup_test failed\n",
 530                        tdata->id);
 531                 goto out;
 532         }
 533
 534         for (step = 10; step > 0; step--) {
 535                 for (i = 0; i < tdata->entries; i += step) {
 536                         if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
 537                                 continue;
 538                         err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
 539                                                      test_rht_params);
 540                         if (err) {
 541                                 pr_err("  thread[%d]: rhashtable_remove_fast failed\n",
 542                                        tdata->id);
 543                                 goto out;
 544                         }
 545                         tdata->objs[i].value.id = TEST_INSERT_FAIL;
 546
 547                         cond_resched();
 548                 }
 549                 err = thread_lookup_test(tdata);
 550                 if (err) {
 551                         pr_err("  thread[%d]: rhashtable_lookup_test (2) failed\n",
 552                                tdata->id);
 553                         goto out;
 554                 }
 555         }
 556 out:
 557         while (!kthread_should_stop()) {
 558                 set_current_state(TASK_INTERRUPTIBLE);
 559                 schedule();
 560         }
 561         return err;
 562 }
 563
 564 static int __init test_rht_init(void)
 565 {
 566         unsigned int entries;
 567         int i, err, started_threads = 0, failed_threads = 0;
 568         u64 total_time = 0;
 569         struct thread_data *tdata;
 570         struct test_obj *objs;
 571
 572         if (parm_entries < 0)
 573                 parm_entries = 1;
 574
 575         entries = min(parm_entries, MAX_ENTRIES);
 576
 577         test_rht_params.automatic_shrinking = shrinking;
 578         test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
 579         test_rht_params.nelem_hint = size;
 580
 581         objs = vzalloc((test_rht_params.max_size + 1) * sizeof(struct test_obj));
 582         if (!objs)
 583                 return -ENOMEM;
 584
 585         pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
 586                 size, max_size, shrinking);
 587
 588         for (i = 0; i < runs; i++) {
 589                 s64 time;
 590
 591                 pr_info("Test %02d:\n", i);
 592                 memset(objs, 0, test_rht_params.max_size * sizeof(struct test_obj));
 593
 594                 err = rhashtable_init(&ht, &test_rht_params);
 595                 if (err < 0) {
 596                         pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 597                                 err);
 598                         continue;
 599                 }
 600
 601                 time = test_rhashtable(&ht, objs, entries);
 602                 rhashtable_destroy(&ht);
 603                 if (time < 0) {
 604                         vfree(objs);
 605                         pr_warn("Test failed: return code %lld\n", time);
 606                         return -EINVAL;
 607                 }
 608
 609                 total_time += time;
 610         }
 611
 612         pr_info("test if its possible to exceed max_size %d: %s\n",
 613                         test_rht_params.max_size, test_rhashtable_max(objs, entries) == 0 ?
 614                         "no, ok" : "YES, failed");
 615         vfree(objs);
 616
 617         do_div(total_time, runs);
 618         pr_info("Average test time: %llu\n", total_time);
 619
 620         if (!tcount)
 621                 return 0;
 622
 623         pr_info("Testing concurrent rhashtable access from %d threads\n",
 624                 tcount);
 625         sema_init(&prestart_sem, 1 - tcount);
 626         tdata = vzalloc(tcount * sizeof(struct thread_data));
 627         if (!tdata)
 628                 return -ENOMEM;
 629         objs  = vzalloc(tcount * entries * sizeof(struct test_obj));
 630         if (!objs) {
 631                 vfree(tdata);
 632                 return -ENOMEM;
 633         }
 634
 635         test_rht_params.max_size = max_size ? :
 636                                    roundup_pow_of_two(tcount * entries);
 637         err = rhashtable_init(&ht, &test_rht_params);
 638         if (err < 0) {
 639                 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 640                         err);
 641                 vfree(tdata);
 642                 vfree(objs);
 643                 return -EINVAL;
 644         }
 645         for (i = 0; i < tcount; i++) {
 646                 tdata[i].id = i;
 647                 tdata[i].entries = entries;
 648                 tdata[i].objs = objs + i * entries;
 649                 tdata[i].task = kthread_run(threadfunc, &tdata[i],
 650                                             "rhashtable_thrad[%d]", i);
 651                 if (IS_ERR(tdata[i].task))
 652                         pr_err(" kthread_run failed for thread %d\n", i);
 653                 else
 654                         started_threads++;
 655         }
 656         if (down_interruptible(&prestart_sem))
 657                 pr_err("  down interruptible failed\n");
 658         for (i = 0; i < tcount; i++)
 659                 up(&startup_sem);
 660         for (i = 0; i < tcount; i++) {
 661                 if (IS_ERR(tdata[i].task))
 662                         continue;
 663                 if ((err = kthread_stop(tdata[i].task))) {
 664                         pr_warn("Test failed: thread %d returned: %d\n",
 665                                 i, err);
 666                         failed_threads++;
 667                 }
 668         }
 669         rhashtable_destroy(&ht);
 670         vfree(tdata);
 671         vfree(objs);
 672
 673         /*
 674          * rhltable_remove is very expensive, default values can cause test
 675          * to run for 2 minutes or more,  use a smaller number instead.
 676          */
 677         err = test_rhltable(entries / 16);
 678         pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
 679                 started_threads, failed_threads, err);
 680         return 0;
 681 }
 682
 683 static void __exit test_rht_exit(void)
 684 {
 685 }
 686
 687 module_init(test_rht_init);
 688 module_exit(test_rht_exit);
 689
 690 MODULE_LICENSE("GPL v2");