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(runs, "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 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 insert_retry(struct rhashtable *ht, struct rhash_head *obj,
  80                         const struct rhashtable_params params)
  81 {
  82         int err, retries = -1;
  83
  84         do {
  85                 retries++;
  86                 cond_resched();
  87                 err = rhashtable_insert_fast(ht, obj, params);
  88         } while (err == -EBUSY);
  89
  90         return err ? : retries;
  91 }
  92
  93 static int __init test_rht_lookup(struct rhashtable *ht)
  94 {
  95         unsigned int i;
  96
  97         for (i = 0; i < entries * 2; i++) {
  98                 struct test_obj *obj;
  99                 bool expected = !(i % 2);
 100                 u32 key = i;
 101
 102                 if (array[i / 2].value == TEST_INSERT_FAIL)
 103                         expected = false;
 104
 105                 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 106
 107                 if (expected && !obj) {
 108                         pr_warn("Test failed: Could not find key %u\n", key);
 109                         return -ENOENT;
 110                 } else if (!expected && obj) {
 111                         pr_warn("Test failed: Unexpected entry found for key %u\n",
 112                                 key);
 113                         return -EEXIST;
 114                 } else if (expected && obj) {
 115                         if (obj->value != i) {
 116                                 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
 117                                         obj->value, i);
 118                                 return -EINVAL;
 119                         }
 120                 }
 121
 122                 cond_resched_rcu();
 123         }
 124
 125         return 0;
 126 }
 127
 128 static void test_bucket_stats(struct rhashtable *ht)
 129 {
 130         unsigned int err, total = 0, chain_len = 0;
 131         struct rhashtable_iter hti;
 132         struct rhash_head *pos;
 133
 134         err = rhashtable_walk_init(ht, &hti);
 135         if (err) {
 136                 pr_warn("Test failed: allocation error");
 137                 return;
 138         }
 139
 140         err = rhashtable_walk_start(&hti);
 141         if (err && err != -EAGAIN) {
 142                 pr_warn("Test failed: iterator failed: %d\n", err);
 143                 return;
 144         }
 145
 146         while ((pos = rhashtable_walk_next(&hti))) {
 147                 if (PTR_ERR(pos) == -EAGAIN) {
 148                         pr_info("Info: encountered resize\n");
 149                         chain_len++;
 150                         continue;
 151                 } else if (IS_ERR(pos)) {
 152                         pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
 153                                 PTR_ERR(pos));
 154                         break;
 155                 }
 156
 157                 total++;
 158         }
 159
 160         rhashtable_walk_stop(&hti);
 161         rhashtable_walk_exit(&hti);
 162
 163         pr_info("  Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
 164                 total, atomic_read(&ht->nelems), entries, chain_len);
 165
 166         if (total != atomic_read(&ht->nelems) || total != entries)
 167                 pr_warn("Test failed: Total count mismatch ^^^");
 168 }
 169
 170 static s64 __init test_rhashtable(struct rhashtable *ht)
 171 {
 172         struct test_obj *obj;
 173         int err;
 174         unsigned int i, insert_retries = 0;
 175         s64 start, end;
 176
 177         /*
 178          * Insertion Test:
 179          * Insert entries into table with all keys even numbers
 180          */
 181         pr_info("  Adding %d keys\n", entries);
 182         start = ktime_get_ns();
 183         for (i = 0; i < entries; i++) {
 184                 struct test_obj *obj = &array[i];
 185
 186                 obj->value = i * 2;
 187                 err = insert_retry(ht, &obj->node, test_rht_params);
 188                 if (err > 0)
 189                         insert_retries += err;
 190                 else if (err)
 191                         return err;
 192         }
 193
 194         if (insert_retries)
 195                 pr_info("  %u insertions retried due to memory pressure\n",
 196                         insert_retries);
 197
 198         test_bucket_stats(ht);
 199         rcu_read_lock();
 200         test_rht_lookup(ht);
 201         rcu_read_unlock();
 202
 203         test_bucket_stats(ht);
 204
 205         pr_info("  Deleting %d keys\n", entries);
 206         for (i = 0; i < entries; i++) {
 207                 u32 key = i * 2;
 208
 209                 if (array[i].value != TEST_INSERT_FAIL) {
 210                         obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 211                         BUG_ON(!obj);
 212
 213                         rhashtable_remove_fast(ht, &obj->node, test_rht_params);
 214                 }
 215
 216                 cond_resched();
 217         }
 218
 219         end = ktime_get_ns();
 220         pr_info("  Duration of test: %lld ns\n", end - start);
 221
 222         return end - start;
 223 }
 224
 225 static struct rhashtable ht;
 226
 227 static int thread_lookup_test(struct thread_data *tdata)
 228 {
 229         int i, err = 0;
 230
 231         for (i = 0; i < entries; i++) {
 232                 struct test_obj *obj;
 233                 int key = (tdata->id << 16) | i;
 234
 235                 obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
 236                 if (obj && (tdata->objs[i].value == TEST_INSERT_FAIL)) {
 237                         pr_err("  found unexpected object %d\n", key);
 238                         err++;
 239                 } else if (!obj && (tdata->objs[i].value != TEST_INSERT_FAIL)) {
 240                         pr_err("  object %d not found!\n", key);
 241                         err++;
 242                 } else if (obj && (obj->value != key)) {
 243                         pr_err("  wrong object returned (got %d, expected %d)\n",
 244                                obj->value, key);
 245                         err++;
 246                 }
 247
 248                 cond_resched();
 249         }
 250         return err;
 251 }
 252
 253 static int threadfunc(void *data)
 254 {
 255         int i, step, err = 0, insert_retries = 0;
 256         struct thread_data *tdata = data;
 257
 258         up(&prestart_sem);
 259         if (down_interruptible(&startup_sem))
 260                 pr_err("  thread[%d]: down_interruptible failed\n", tdata->id);
 261
 262         for (i = 0; i < entries; i++) {
 263                 tdata->objs[i].value = (tdata->id << 16) | i;
 264                 err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params);
 265                 if (err > 0) {
 266                         insert_retries += err;
 267                 } else if (err) {
 268                         pr_err("  thread[%d]: rhashtable_insert_fast failed\n",
 269                                tdata->id);
 270                         goto out;
 271                 }
 272         }
 273         if (insert_retries)
 274                 pr_info("  thread[%d]: %u insertions retried due to memory pressure\n",
 275                         tdata->id, insert_retries);
 276
 277         err = thread_lookup_test(tdata);
 278         if (err) {
 279                 pr_err("  thread[%d]: rhashtable_lookup_test failed\n",
 280                        tdata->id);
 281                 goto out;
 282         }
 283
 284         for (step = 10; step > 0; step--) {
 285                 for (i = 0; i < entries; i += step) {
 286                         if (tdata->objs[i].value == TEST_INSERT_FAIL)
 287                                 continue;
 288                         err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
 289                                                      test_rht_params);
 290                         if (err) {
 291                                 pr_err("  thread[%d]: rhashtable_remove_fast failed\n",
 292                                        tdata->id);
 293                                 goto out;
 294                         }
 295                         tdata->objs[i].value = TEST_INSERT_FAIL;
 296
 297                         cond_resched();
 298                 }
 299                 err = thread_lookup_test(tdata);
 300                 if (err) {
 301                         pr_err("  thread[%d]: rhashtable_lookup_test (2) failed\n",
 302                                tdata->id);
 303                         goto out;
 304                 }
 305         }
 306 out:
 307         while (!kthread_should_stop()) {
 308                 set_current_state(TASK_INTERRUPTIBLE);
 309                 schedule();
 310         }
 311         return err;
 312 }
 313
 314 static int __init test_rht_init(void)
 315 {
 316         int i, err, started_threads = 0, failed_threads = 0;
 317         u64 total_time = 0;
 318         struct thread_data *tdata;
 319         struct test_obj *objs;
 320
 321         entries = min(entries, MAX_ENTRIES);
 322
 323         test_rht_params.automatic_shrinking = shrinking;
 324         test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
 325         test_rht_params.nelem_hint = size;
 326
 327         pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
 328                 size, max_size, shrinking);
 329
 330         for (i = 0; i < runs; i++) {
 331                 s64 time;
 332
 333                 pr_info("Test %02d:\n", i);
 334                 memset(&array, 0, sizeof(array));
 335                 err = rhashtable_init(&ht, &test_rht_params);
 336                 if (err < 0) {
 337                         pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 338                                 err);
 339                         continue;
 340                 }
 341
 342                 time = test_rhashtable(&ht);
 343                 rhashtable_destroy(&ht);
 344                 if (time < 0) {
 345                         pr_warn("Test failed: return code %lld\n", time);
 346                         return -EINVAL;
 347                 }
 348
 349                 total_time += time;
 350         }
 351
 352         do_div(total_time, runs);
 353         pr_info("Average test time: %llu\n", total_time);
 354
 355         if (!tcount)
 356                 return 0;
 357
 358         pr_info("Testing concurrent rhashtable access from %d threads\n",
 359                 tcount);
 360         sema_init(&prestart_sem, 1 - tcount);
 361         tdata = vzalloc(tcount * sizeof(struct thread_data));
 362         if (!tdata)
 363                 return -ENOMEM;
 364         objs  = vzalloc(tcount * entries * sizeof(struct test_obj));
 365         if (!objs) {
 366                 vfree(tdata);
 367                 return -ENOMEM;
 368         }
 369
 370         test_rht_params.max_size = max_size ? :
 371                                    roundup_pow_of_two(tcount * entries);
 372         err = rhashtable_init(&ht, &test_rht_params);
 373         if (err < 0) {
 374                 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 375                         err);
 376                 vfree(tdata);
 377                 vfree(objs);
 378                 return -EINVAL;
 379         }
 380         for (i = 0; i < tcount; i++) {
 381                 tdata[i].id = i;
 382                 tdata[i].objs = objs + i * entries;
 383                 tdata[i].task = kthread_run(threadfunc, &tdata[i],
 384                                             "rhashtable_thrad[%d]", i);
 385                 if (IS_ERR(tdata[i].task))
 386                         pr_err(" kthread_run failed for thread %d\n", i);
 387                 else
 388                         started_threads++;
 389         }
 390         if (down_interruptible(&prestart_sem))
 391                 pr_err("  down interruptible failed\n");
 392         for (i = 0; i < tcount; i++)
 393                 up(&startup_sem);
 394         for (i = 0; i < tcount; i++) {
 395                 if (IS_ERR(tdata[i].task))
 396                         continue;
 397                 if ((err = kthread_stop(tdata[i].task))) {
 398                         pr_warn("Test failed: thread %d returned: %d\n",
 399                                 i, err);
 400                         failed_threads++;
 401                 }
 402         }
 403         pr_info("Started %d threads, %d failed\n",
 404                 started_threads, failed_threads);
 405         rhashtable_destroy(&ht);
 406         vfree(tdata);
 407         vfree(objs);
 408         return 0;
 409 }
 410
 411 static void __exit test_rht_exit(void)
 412 {
 413 }
 414
 415 module_init(test_rht_init);
 416 module_exit(test_rht_exit);
 417
 418 MODULE_LICENSE("GPL v2");