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 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 {
  60         int                     value;
  61         struct rhash_head       node;
  62 };
  63
  64 struct thread_data {
  65         int id;
  66         struct task_struct *task;
  67         struct test_obj *objs;
  68 };
  69
  70 static struct test_obj array[MAX_ENTRIES];
  71
  72 static struct rhashtable_params test_rht_params = {
  73         .head_offset = offsetof(struct test_obj, node),
  74         .key_offset = offsetof(struct test_obj, value),
  75         .key_len = sizeof(int),
  76         .hashfn = jhash,
  77         .nulls_base = (3U << RHT_BASE_SHIFT),
  78 };
  79
  80 static struct semaphore prestart_sem;
  81 static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);
  82
  83 static int insert_retry(struct rhashtable *ht, struct rhash_head *obj,
  84                         const struct rhashtable_params params)
  85 {
  86         int err, retries = -1, enomem_retries = 0;
  87
  88         do {
  89                 retries++;
  90                 cond_resched();
  91                 err = rhashtable_insert_fast(ht, obj, params);
  92                 if (err == -ENOMEM && enomem_retry) {
  93                         enomem_retries++;
  94                         err = -EBUSY;
  95                 }
  96         } while (err == -EBUSY);
  97
  98         if (enomem_retries)
  99                 pr_info(" %u insertions retried after -ENOMEM\n",
 100                         enomem_retries);
 101
 102         return err ? : retries;
 103 }
 104
 105 static int __init test_rht_lookup(struct rhashtable *ht)
 106 {
 107         unsigned int i;
 108
 109         for (i = 0; i < entries * 2; i++) {
 110                 struct test_obj *obj;
 111                 bool expected = !(i % 2);
 112                 u32 key = i;
 113
 114                 if (array[i / 2].value == TEST_INSERT_FAIL)
 115                         expected = false;
 116
 117                 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 118
 119                 if (expected && !obj) {
 120                         pr_warn("Test failed: Could not find key %u\n", key);
 121                         return -ENOENT;
 122                 } else if (!expected && obj) {
 123                         pr_warn("Test failed: Unexpected entry found for key %u\n",
 124                                 key);
 125                         return -EEXIST;
 126                 } else if (expected && obj) {
 127                         if (obj->value != i) {
 128                                 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
 129                                         obj->value, i);
 130                                 return -EINVAL;
 131                         }
 132                 }
 133
 134                 cond_resched_rcu();
 135         }
 136
 137         return 0;
 138 }
 139
 140 static void test_bucket_stats(struct rhashtable *ht)
 141 {
 142         unsigned int err, total = 0, chain_len = 0;
 143         struct rhashtable_iter hti;
 144         struct rhash_head *pos;
 145
 146         err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
 147         if (err) {
 148                 pr_warn("Test failed: allocation error");
 149                 return;
 150         }
 151
 152         err = rhashtable_walk_start(&hti);
 153         if (err && err != -EAGAIN) {
 154                 pr_warn("Test failed: iterator failed: %d\n", err);
 155                 return;
 156         }
 157
 158         while ((pos = rhashtable_walk_next(&hti))) {
 159                 if (PTR_ERR(pos) == -EAGAIN) {
 160                         pr_info("Info: encountered resize\n");
 161                         chain_len++;
 162                         continue;
 163                 } else if (IS_ERR(pos)) {
 164                         pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
 165                                 PTR_ERR(pos));
 166                         break;
 167                 }
 168
 169                 total++;
 170         }
 171
 172         rhashtable_walk_stop(&hti);
 173         rhashtable_walk_exit(&hti);
 174
 175         pr_info("  Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
 176                 total, atomic_read(&ht->nelems), entries, chain_len);
 177
 178         if (total != atomic_read(&ht->nelems) || total != entries)
 179                 pr_warn("Test failed: Total count mismatch ^^^");
 180 }
 181
 182 static s64 __init test_rhashtable(struct rhashtable *ht)
 183 {
 184         struct test_obj *obj;
 185         int err;
 186         unsigned int i, insert_retries = 0;
 187         s64 start, end;
 188
 189         /*
 190          * Insertion Test:
 191          * Insert entries into table with all keys even numbers
 192          */
 193         pr_info("  Adding %d keys\n", entries);
 194         start = ktime_get_ns();
 195         for (i = 0; i < entries; i++) {
 196                 struct test_obj *obj = &array[i];
 197
 198                 obj->value = i * 2;
 199                 err = insert_retry(ht, &obj->node, test_rht_params);
 200                 if (err > 0)
 201                         insert_retries += err;
 202                 else if (err)
 203                         return err;
 204         }
 205
 206         if (insert_retries)
 207                 pr_info("  %u insertions retried due to memory pressure\n",
 208                         insert_retries);
 209
 210         test_bucket_stats(ht);
 211         rcu_read_lock();
 212         test_rht_lookup(ht);
 213         rcu_read_unlock();
 214
 215         test_bucket_stats(ht);
 216
 217         pr_info("  Deleting %d keys\n", entries);
 218         for (i = 0; i < entries; i++) {
 219                 u32 key = i * 2;
 220
 221                 if (array[i].value != TEST_INSERT_FAIL) {
 222                         obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
 223                         BUG_ON(!obj);
 224
 225                         rhashtable_remove_fast(ht, &obj->node, test_rht_params);
 226                 }
 227
 228                 cond_resched();
 229         }
 230
 231         end = ktime_get_ns();
 232         pr_info("  Duration of test: %lld ns\n", end - start);
 233
 234         return end - start;
 235 }
 236
 237 static struct rhashtable ht;
 238
 239 static int thread_lookup_test(struct thread_data *tdata)
 240 {
 241         int i, err = 0;
 242
 243         for (i = 0; i < entries; i++) {
 244                 struct test_obj *obj;
 245                 int key = (tdata->id << 16) | i;
 246
 247                 obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
 248                 if (obj && (tdata->objs[i].value == TEST_INSERT_FAIL)) {
 249                         pr_err("  found unexpected object %d\n", key);
 250                         err++;
 251                 } else if (!obj && (tdata->objs[i].value != TEST_INSERT_FAIL)) {
 252                         pr_err("  object %d not found!\n", key);
 253                         err++;
 254                 } else if (obj && (obj->value != key)) {
 255                         pr_err("  wrong object returned (got %d, expected %d)\n",
 256                                obj->value, key);
 257                         err++;
 258                 }
 259
 260                 cond_resched();
 261         }
 262         return err;
 263 }
 264
 265 static int threadfunc(void *data)
 266 {
 267         int i, step, err = 0, insert_retries = 0;
 268         struct thread_data *tdata = data;
 269
 270         up(&prestart_sem);
 271         if (down_interruptible(&startup_sem))
 272                 pr_err("  thread[%d]: down_interruptible failed\n", tdata->id);
 273
 274         for (i = 0; i < entries; i++) {
 275                 tdata->objs[i].value = (tdata->id << 16) | i;
 276                 err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params);
 277                 if (err > 0) {
 278                         insert_retries += err;
 279                 } else if (err) {
 280                         pr_err("  thread[%d]: rhashtable_insert_fast failed\n",
 281                                tdata->id);
 282                         goto out;
 283                 }
 284         }
 285         if (insert_retries)
 286                 pr_info("  thread[%d]: %u insertions retried due to memory pressure\n",
 287                         tdata->id, insert_retries);
 288
 289         err = thread_lookup_test(tdata);
 290         if (err) {
 291                 pr_err("  thread[%d]: rhashtable_lookup_test failed\n",
 292                        tdata->id);
 293                 goto out;
 294         }
 295
 296         for (step = 10; step > 0; step--) {
 297                 for (i = 0; i < entries; i += step) {
 298                         if (tdata->objs[i].value == TEST_INSERT_FAIL)
 299                                 continue;
 300                         err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
 301                                                      test_rht_params);
 302                         if (err) {
 303                                 pr_err("  thread[%d]: rhashtable_remove_fast failed\n",
 304                                        tdata->id);
 305                                 goto out;
 306                         }
 307                         tdata->objs[i].value = TEST_INSERT_FAIL;
 308
 309                         cond_resched();
 310                 }
 311                 err = thread_lookup_test(tdata);
 312                 if (err) {
 313                         pr_err("  thread[%d]: rhashtable_lookup_test (2) failed\n",
 314                                tdata->id);
 315                         goto out;
 316                 }
 317         }
 318 out:
 319         while (!kthread_should_stop()) {
 320                 set_current_state(TASK_INTERRUPTIBLE);
 321                 schedule();
 322         }
 323         return err;
 324 }
 325
 326 static int __init test_rht_init(void)
 327 {
 328         int i, err, started_threads = 0, failed_threads = 0;
 329         u64 total_time = 0;
 330         struct thread_data *tdata;
 331         struct test_obj *objs;
 332
 333         entries = min(entries, MAX_ENTRIES);
 334
 335         test_rht_params.automatic_shrinking = shrinking;
 336         test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
 337         test_rht_params.nelem_hint = size;
 338
 339         pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
 340                 size, max_size, shrinking);
 341
 342         for (i = 0; i < runs; i++) {
 343                 s64 time;
 344
 345                 pr_info("Test %02d:\n", i);
 346                 memset(&array, 0, sizeof(array));
 347                 err = rhashtable_init(&ht, &test_rht_params);
 348                 if (err < 0) {
 349                         pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 350                                 err);
 351                         continue;
 352                 }
 353
 354                 time = test_rhashtable(&ht);
 355                 rhashtable_destroy(&ht);
 356                 if (time < 0) {
 357                         pr_warn("Test failed: return code %lld\n", time);
 358                         return -EINVAL;
 359                 }
 360
 361                 total_time += time;
 362         }
 363
 364         do_div(total_time, runs);
 365         pr_info("Average test time: %llu\n", total_time);
 366
 367         if (!tcount)
 368                 return 0;
 369
 370         pr_info("Testing concurrent rhashtable access from %d threads\n",
 371                 tcount);
 372         sema_init(&prestart_sem, 1 - tcount);
 373         tdata = vzalloc(tcount * sizeof(struct thread_data));
 374         if (!tdata)
 375                 return -ENOMEM;
 376         objs  = vzalloc(tcount * entries * sizeof(struct test_obj));
 377         if (!objs) {
 378                 vfree(tdata);
 379                 return -ENOMEM;
 380         }
 381
 382         test_rht_params.max_size = max_size ? :
 383                                    roundup_pow_of_two(tcount * entries);
 384         err = rhashtable_init(&ht, &test_rht_params);
 385         if (err < 0) {
 386                 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
 387                         err);
 388                 vfree(tdata);
 389                 vfree(objs);
 390                 return -EINVAL;
 391         }
 392         for (i = 0; i < tcount; i++) {
 393                 tdata[i].id = i;
 394                 tdata[i].objs = objs + i * entries;
 395                 tdata[i].task = kthread_run(threadfunc, &tdata[i],
 396                                             "rhashtable_thrad[%d]", i);
 397                 if (IS_ERR(tdata[i].task))
 398                         pr_err(" kthread_run failed for thread %d\n", i);
 399                 else
 400                         started_threads++;
 401         }
 402         if (down_interruptible(&prestart_sem))
 403                 pr_err("  down interruptible failed\n");
 404         for (i = 0; i < tcount; i++)
 405                 up(&startup_sem);
 406         for (i = 0; i < tcount; i++) {
 407                 if (IS_ERR(tdata[i].task))
 408                         continue;
 409                 if ((err = kthread_stop(tdata[i].task))) {
 410                         pr_warn("Test failed: thread %d returned: %d\n",
 411                                 i, err);
 412                         failed_threads++;
 413                 }
 414         }
 415         pr_info("Started %d threads, %d failed\n",
 416                 started_threads, failed_threads);
 417         rhashtable_destroy(&ht);
 418         vfree(tdata);
 419         vfree(objs);
 420         return 0;
 421 }
 422
 423 static void __exit test_rht_exit(void)
 424 {
 425 }
 426
 427 module_init(test_rht_init);
 428 module_exit(test_rht_exit);
 429
 430 MODULE_LICENSE("GPL v2");