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 = 0;
  40 module_param(max_size, int, 0);
  41 MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");
  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 static bool enomem_retry = false;
  56 module_param(enomem_retry, bool, 0);
  57 MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");
  58
  59 struct test_obj_val {
  60         int     id;
  61         int     tid;
  62 };
  63
  64 struct test_obj {
  65         struct test_obj_val     value;
  66         struct rhash_head       node;
  67 };
  68
  69 struct thread_data {
  70         int id;
  71         struct task_struct *task;
  72         struct test_obj *objs;
  73 };
  74
  75 static struct test_obj array[MAX_ENTRIES];
  76
  77 static struct rhashtable_params test_rht_params = {
  78         .head_offset = offsetof(struct test_obj, node),
  79         .key_offset = offsetof(struct test_obj, value),
  80         .key_len = sizeof(struct test_obj_val),
  81         .hashfn = jhash,
  82         .nulls_base = (3U << RHT_BASE_SHIFT),
  83 };
  84
  85 static struct semaphore prestart_sem;
  86 static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);
  87
  88 static int insert_retry(struct rhashtable *ht, struct rhash_head *obj,
  89                         const struct rhashtable_params params)
  90 {
  91         int err, retries = -1, enomem_retries = 0;
  92
  93         do {
  94                 retries++;
  95                 cond_resched();
  96                 err = rhashtable_insert_fast(ht, obj, params);
  97                 if (err == -ENOMEM && enomem_retry) {
  98                         enomem_retries++;
  99                         err = -EBUSY;
 100                 }
 101         } while (err == -EBUSY);
 102
 103         if (enomem_retries)
 104                 pr_info(" %u insertions retried after -ENOMEM\n",
 105                         enomem_retries);
 106
 107         return err ? : retries;
 108 }
 109
 110 static int __init test_rht_lookup(struct rhashtable *ht)
 111 {
 112         unsigned int i;
 113
 114         for (i = 0; i < entries * 2; i++) {
 115                 struct test_obj *obj;
 116                 bool expected = !(i % 2);
 117                 struct test_obj_val key = {
 118                         .id = i,
 119                 };
 120
 121                 if (array[i / 2].value.id == TEST_INSERT_FAIL)
 122                         expected = false;
 123
 124                 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 125
 126                 if (expected && !obj) {
 127                         pr_warn("Test failed: Could not find key %u\n", key.id);
 128                         return -ENOENT;
 129                 } else if (!expected && obj) {
 130                         pr_warn("Test failed: Unexpected entry found for key %u\n",
 131                                 key.id);
 132                         return -EEXIST;
 133                 } else if (expected && obj) {
 134                         if (obj->value.id != i) {
 135                                 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
 136                                         obj->value.id, i);
 137                                 return -EINVAL;
 138                         }
 139                 }
 140
 141                 cond_resched_rcu();
 142         }
 143
 144         return 0;
 145 }
 146
 147 static void test_bucket_stats(struct rhashtable *ht)
 148 {
 149         unsigned int err, total = 0, chain_len = 0;
 150         struct rhashtable_iter hti;
 151         struct rhash_head *pos;
 152
 153         err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
 154         if (err) {
 155                 pr_warn("Test failed: allocation error");
 156                 return;
 157         }
 158
 159         err = rhashtable_walk_start(&hti);
 160         if (err && err != -EAGAIN) {
 161                 pr_warn("Test failed: iterator failed: %d\n", err);
 162                 return;
 163         }
 164
 165         while ((pos = rhashtable_walk_next(&hti))) {
 166                 if (PTR_ERR(pos) == -EAGAIN) {
 167                         pr_info("Info: encountered resize\n");
 168                         chain_len++;
 169                         continue;
 170                 } else if (IS_ERR(pos)) {
 171                         pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
 172                                 PTR_ERR(pos));
 173                         break;
 174                 }
 175
 176                 total++;
 177         }
 178
 179         rhashtable_walk_stop(&hti);
 180         rhashtable_walk_exit(&hti);
 181
 182         pr_info("  Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
 183                 total, atomic_read(&ht->nelems), entries, chain_len);
 184
 185         if (total != atomic_read(&ht->nelems) || total != entries)
 186                 pr_warn("Test failed: Total count mismatch ^^^");
 187 }
 188
 189 static s64 __init test_rhashtable(struct rhashtable *ht)
 190 {
 191         struct test_obj *obj;
 192         int err;
 193         unsigned int i, insert_retries = 0;
 194         s64 start, end;
 195
 196         /*
 197          * Insertion Test:
 198          * Insert entries into table with all keys even numbers
 199          */
 200         pr_info("  Adding %d keys\n", entries);
 201         start = ktime_get_ns();
 202         for (i = 0; i < entries; i++) {
 203                 struct test_obj *obj = &array[i];
 204
 205                 obj->value.id = i * 2;
 206                 err = insert_retry(ht, &obj->node, test_rht_params);
 207                 if (err > 0)
 208                         insert_retries += err;
 209                 else if (err)
 210                         return err;
 211         }
 212
 213         if (insert_retries)
 214                 pr_info("  %u insertions retried due to memory pressure\n",
 215                         insert_retries);
 216
 217         test_bucket_stats(ht);
 218         rcu_read_lock();
 219         test_rht_lookup(ht);
 220         rcu_read_unlock();
 221
 222         test_bucket_stats(ht);
 223
 224         pr_info("  Deleting %d keys\n", entries);
 225         for (i = 0; i < entries; i++) {
 226                 struct test_obj_val key = {
 227                         .id = i * 2,
 228                 };
 229
 230                 if (array[i].value.id != TEST_INSERT_FAIL) {
 231                         obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 232                         BUG_ON(!obj);
 233
 234                         rhashtable_remove_fast(ht, &obj->node, test_rht_params);
 235                 }
 236
 237                 cond_resched();
 238         }
 239
 240         end = ktime_get_ns();
 241         pr_info("  Duration of test: %lld ns\n", end - start);
 242
 243         return end - start;
 244 }
 245
 246 static struct rhashtable ht;
 247
 248 static int thread_lookup_test(struct thread_data *tdata)
 249 {
 250         int i, err = 0;
 251
 252         for (i = 0; i < entries; i++) {
 253                 struct test_obj *obj;
 254                 struct test_obj_val key = {
 255                         .id = i,
 256                         .tid = tdata->id,
 257                 };
 258
 259                 obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
 260                 if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
 261                         pr_err("  found unexpected object %d-%d\n", key.tid, key.id);
 262                         err++;
 263                 } else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
 264                         pr_err("  object %d-%d not found!\n", key.tid, key.id);
 265                         err++;
 266                 } else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
 267                         pr_err("  wrong object returned (got %d-%d, expected %d-%d)\n",
 268                                obj->value.tid, obj->value.id, key.tid, key.id);
 269                         err++;
 270                 }
 271
 272                 cond_resched();
 273         }
 274         return err;
 275 }
 276
 277 static int threadfunc(void *data)
 278 {
 279         int i, step, err = 0, insert_retries = 0;
 280         struct thread_data *tdata = data;
 281
 282         up(&prestart_sem);
 283         if (down_interruptible(&startup_sem))
 284                 pr_err("  thread[%d]: down_interruptible failed\n", tdata->id);
 285
 286         for (i = 0; i < entries; i++) {
 287                 tdata->objs[i].value.id = i;
 288                 tdata->objs[i].value.tid = tdata->id;
 289                 err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params);
 290                 if (err > 0) {
 291                         insert_retries += err;
 292                 } else if (err) {
 293                         pr_err("  thread[%d]: rhashtable_insert_fast failed\n",
 294                                tdata->id);
 295                         goto out;
 296                 }
 297         }
 298         if (insert_retries)
 299                 pr_info("  thread[%d]: %u insertions retried due to memory pressure\n",
 300                         tdata->id, insert_retries);
 301
 302         err = thread_lookup_test(tdata);
 303         if (err) {
 304                 pr_err("  thread[%d]: rhashtable_lookup_test failed\n",
 305                        tdata->id);
 306                 goto out;
 307         }
 308
 309         for (step = 10; step > 0; step--) {
 310                 for (i = 0; i < entries; i += step) {
 311                         if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
 312                                 continue;
 313                         err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
 314                                                      test_rht_params);
 315                         if (err) {
 316                                 pr_err("  thread[%d]: rhashtable_remove_fast failed\n",
 317                                        tdata->id);
 318                                 goto out;
 319                         }
 320                         tdata->objs[i].value.id = TEST_INSERT_FAIL;
 321
 322                         cond_resched();
 323                 }
 324                 err = thread_lookup_test(tdata);
 325                 if (err) {
 326                         pr_err("  thread[%d]: rhashtable_lookup_test (2) failed\n",
 327                                tdata->id);
 328                         goto out;
 329                 }
 330         }
 331 out:
 332         while (!kthread_should_stop()) {
 333                 set_current_state(TASK_INTERRUPTIBLE);
 334                 schedule();
 335         }
 336         return err;
 337 }
 338
 339 static int __init test_rht_init(void)
 340 {
 341         int i, err, started_threads = 0, failed_threads = 0;
 342         u64 total_time = 0;
 343         struct thread_data *tdata;
 344         struct test_obj *objs;
 345
 346         entries = min(entries, MAX_ENTRIES);
 347
 348         test_rht_params.automatic_shrinking = shrinking;
 349         test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
 350         test_rht_params.nelem_hint = size;
 351
 352         pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
 353                 size, max_size, shrinking);
 354
 355         for (i = 0; i < runs; i++) {
 356                 s64 time;
 357
 358                 pr_info("Test %02d:\n", i);
 359                 memset(&array, 0, sizeof(array));
 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                         continue;
 365                 }
 366
 367                 time = test_rhashtable(&ht);
 368                 rhashtable_destroy(&ht);
 369                 if (time < 0) {
 370                         pr_warn("Test failed: return code %lld\n", time);
 371                         return -EINVAL;
 372                 }
 373
 374                 total_time += time;
 375         }
 376
 377         do_div(total_time, runs);
 378         pr_info("Average test time: %llu\n", total_time);
 379
 380         if (!tcount)
 381                 return 0;
 382
 383         pr_info("Testing concurrent rhashtable access from %d threads\n",
 384                 tcount);
 385         sema_init(&prestart_sem, 1 - tcount);
 386         tdata = vzalloc(tcount * sizeof(struct thread_data));
 387         if (!tdata)
 388                 return -ENOMEM;
 389         objs  = vzalloc(tcount * entries * sizeof(struct test_obj));
 390         if (!objs) {
 391                 vfree(tdata);
 392                 return -ENOMEM;
 393         }
 394
 395         test_rht_params.max_size = max_size ? :
 396                                    roundup_pow_of_two(tcount * entries);
 397         err = rhashtable_init(&ht, &test_rht_params);
 398         if (err < 0) {
 399                 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 400                         err);
 401                 vfree(tdata);
 402                 vfree(objs);
 403                 return -EINVAL;
 404         }
 405         for (i = 0; i < tcount; i++) {
 406                 tdata[i].id = i;
 407                 tdata[i].objs = objs + i * entries;
 408                 tdata[i].task = kthread_run(threadfunc, &tdata[i],
 409                                             "rhashtable_thrad[%d]", i);
 410                 if (IS_ERR(tdata[i].task))
 411                         pr_err(" kthread_run failed for thread %d\n", i);
 412                 else
 413                         started_threads++;
 414         }
 415         if (down_interruptible(&prestart_sem))
 416                 pr_err("  down interruptible failed\n");
 417         for (i = 0; i < tcount; i++)
 418                 up(&startup_sem);
 419         for (i = 0; i < tcount; i++) {
 420                 if (IS_ERR(tdata[i].task))
 421                         continue;
 422                 if ((err = kthread_stop(tdata[i].task))) {
 423                         pr_warn("Test failed: thread %d returned: %d\n",
 424                                 i, err);
 425                         failed_threads++;
 426                 }
 427         }
 428         pr_info("Started %d threads, %d failed\n",
 429                 started_threads, failed_threads);
 430         rhashtable_destroy(&ht);
 431         vfree(tdata);
 432         vfree(objs);
 433         return 0;
 434 }
 435
 436 static void __exit test_rht_exit(void)
 437 {
 438 }
 439
 440 module_init(test_rht_init);
 441 module_exit(test_rht_exit);
 442
 443 MODULE_LICENSE("GPL v2");