summaryrefslogtreecommitdiffstats
path: root/lib/test_rhashtable.c
blob: aecc0996628f8efd3896de21aed7cd87753f2609 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
/*
 * Resizable, Scalable, Concurrent Hash Table
 *
 * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/**************************************************************************
 * Self Test
 **************************************************************************/

#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/rcupdate.h>
#include <linux/rhashtable.h>
#include <linux/semaphore.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/random.h>
#include <linux/vmalloc.h>

#define MAX_ENTRIES	1000000
#define TEST_INSERT_FAIL INT_MAX

static int parm_entries = 50000;
module_param(parm_entries, int, 0);
MODULE_PARM_DESC(parm_entries, "Number of entries to add (default: 50000)");

static int runs = 4;
module_param(runs, int, 0);
MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");

static int max_size = 0;
module_param(max_size, int, 0);
MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");

static bool shrinking = false;
module_param(shrinking, bool, 0);
MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");

static int size = 8;
module_param(size, int, 0);
MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");

static int tcount = 10;
module_param(tcount, int, 0);
MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");

static bool enomem_retry = false;
module_param(enomem_retry, bool, 0);
MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");

struct test_obj_val {
	int	id;
	int	tid;
};

struct test_obj {
	struct test_obj_val	value;
	struct rhash_head	node;
};

struct test_obj_rhl {
	struct test_obj_val	value;
	struct rhlist_head	list_node;
};

struct thread_data {
	unsigned int entries;
	int id;
	struct task_struct *task;
	struct test_obj *objs;
};

static u32 my_hashfn(const void *data, u32 len, u32 seed)
{
	const struct test_obj_rhl *obj = data;

	return (obj->value.id % 10);
}

static int my_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
{
	const struct test_obj_rhl *test_obj = obj;
	const struct test_obj_val *val = arg->key;

	return test_obj->value.id - val->id;
}

static struct rhashtable_params test_rht_params = {
	.head_offset = offsetof(struct test_obj, node),
	.key_offset = offsetof(struct test_obj, value),
	.key_len = sizeof(struct test_obj_val),
	.hashfn = jhash,
};

static struct rhashtable_params test_rht_params_dup = {
	.head_offset = offsetof(struct test_obj_rhl, list_node),
	.key_offset = offsetof(struct test_obj_rhl, value),
	.key_len = sizeof(struct test_obj_val),
	.hashfn = jhash,
	.obj_hashfn = my_hashfn,
	.obj_cmpfn = my_cmpfn,
	.nelem_hint = 128,
	.automatic_shrinking = false,
};

static struct semaphore prestart_sem;
static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);

static int insert_retry(struct rhashtable *ht, struct test_obj *obj,
                        const struct rhashtable_params params)
{
	int err, retries = -1, enomem_retries = 0;

	do {
		retries++;
		cond_resched();
		err = rhashtable_insert_fast(ht, &obj->node, params);
		if (err == -ENOMEM && enomem_retry) {
			enomem_retries++;
			err = -EBUSY;
		}
	} while (err == -EBUSY);

	if (enomem_retries)
		pr_info(" %u insertions retried after -ENOMEM\n",
			enomem_retries);

	return err ? : retries;
}

static int __init test_rht_lookup(struct rhashtable *ht, struct test_obj *array,
				  unsigned int entries)
{
	unsigned int i;

	for (i = 0; i < entries; i++) {
		struct test_obj *obj;
		bool expected = !(i % 2);
		struct test_obj_val key = {
			.id = i,
		};

		if (array[i / 2].value.id == TEST_INSERT_FAIL)
			expected = false;

		obj = rhashtable_lookup_fast(ht, &key, test_rht_params);

		if (expected && !obj) {
			pr_warn("Test failed: Could not find key %u\n", key.id);
			return -ENOENT;
		} else if (!expected && obj) {
			pr_warn("Test failed: Unexpected entry found for key %u\n",
				key.id);
			return -EEXIST;
		} else if (expected && obj) {
			if (obj->value.id != i) {
				pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
					obj->value.id, i);
				return -EINVAL;
			}
		}

		cond_resched_rcu();
	}

	return 0;
}

static void test_bucket_stats(struct rhashtable *ht, unsigned int entries)
{
	unsigned int err, total = 0, chain_len = 0;
	struct rhashtable_iter hti;
	struct rhash_head *pos;

	err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
	if (err) {
		pr_warn("Test failed: allocation error");
		return;
	}

	rhashtable_walk_start(&hti);

	while ((pos = rhashtable_walk_next(&hti))) {
		if (PTR_ERR(pos) == -EAGAIN) {
			pr_info("Info: encountered resize\n");
			chain_len++;
			continue;
		} else if (IS_ERR(pos)) {
			pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
				PTR_ERR(pos));
			break;
		}

		total++;
	}

	rhashtable_walk_stop(&hti);
	rhashtable_walk_exit(&hti);

	pr_info("  Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
		total, atomic_read(&ht->nelems), entries, chain_len);

	if (total != atomic_read(&ht->nelems) || total != entries)
		pr_warn("Test failed: Total count mismatch ^^^");
}

static s64 __init test_rhashtable(struct rhashtable *ht, struct test_obj *array,
				  unsigned int entries)
{
	struct test_obj *obj;
	int err;
	unsigned int i, insert_retries = 0;
	s64 start, end;

	/*
	 * Insertion Test:
	 * Insert entries into table with all keys even numbers
	 */
	pr_info("  Adding %d keys\n", entries);
	start = ktime_get_ns();
	for (i = 0; i < entries; i++) {
		struct test_obj *obj = &array[i];

		obj->value.id = i * 2;
		err = insert_retry(ht, obj, test_rht_params);
		if (err > 0)
			insert_retries += err;
		else if (err)
			return err;
	}

	if (insert_retries)
		pr_info("  %u insertions retried due to memory pressure\n",
			insert_retries);

	test_bucket_stats(ht, entries);
	rcu_read_lock();
	test_rht_lookup(ht, array, entries);
	rcu_read_unlock();

	test_bucket_stats(ht, entries);

	pr_info("  Deleting %d keys\n", entries);
	for (i = 0; i < entries; i++) {
		struct test_obj_val key = {
			.id = i * 2,
		};

		if (array[i].value.id != TEST_INSERT_FAIL) {
			obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
			BUG_ON(!obj);

			rhashtable_remove_fast(ht, &obj->node, test_rht_params);
		}

		cond_resched();
	}

	end = ktime_get_ns();
	pr_info("  Duration of test: %lld ns\n", end - start);

	return end - start;
}

static struct rhashtable ht;
static struct rhltable rhlt;

static int __init test_rhltable(unsigned int entries)
{
	struct test_obj_rhl *rhl_test_objects;
	unsigned long *obj_in_table;
	unsigned int i, j, k;
	int ret, err;

	if (entries == 0)
		entries = 1;

	rhl_test_objects = vzalloc(array_size(entries,
					      sizeof(*rhl_test_objects)));
	if (!rhl_test_objects)
		return -ENOMEM;

	ret = -ENOMEM;
	obj_in_table = vzalloc(array_size(sizeof(unsigned long),
					  BITS_TO_LONGS(entries)));
	if (!obj_in_table)
		goto out_free;

	err = rhltable_init(&rhlt, &test_rht_params);
	if (WARN_ON(err))
		goto out_free;

	k = prandom_u32();
	ret = 0;
	for (i = 0; i < entries; i++) {
		rhl_test_objects[i].value.id = k;
		err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
				      test_rht_params);
		if (WARN(err, "error %d on element %d\n", err, i))
			break;
		if (err == 0)
			set_bit(i, obj_in_table);
	}

	if (err)
		ret = err;

	pr_info("test %d add/delete pairs into rhlist\n", entries);
	for (i = 0; i < entries; i++) {
		struct rhlist_head *h, *pos;
		struct test_obj_rhl *obj;
		struct test_obj_val key = {
			.id = k,
		};
		bool found;

		rcu_read_lock();
		h = rhltable_lookup(&rhlt, &key, test_rht_params);
		if (WARN(!h, "key not found during iteration %d of %d", i, entries)) {
			rcu_read_unlock();
			break;
		}

		if (i) {
			j = i - 1;
			rhl_for_each_entry_rcu(obj, pos, h, list_node) {
				if (WARN(pos == &rhl_test_objects[j].list_node, "old element found, should be gone"))
					break;
			}
		}

		cond_resched_rcu();

		found = false;

		rhl_for_each_entry_rcu(obj, pos, h, list_node) {
			if (pos == &rhl_test_objects[i].list_node) {
				found = true;
				break;
			}
		}

		rcu_read_unlock();

		if (WARN(!found, "element %d not found", i))
			break;

		err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
		WARN(err, "rhltable_remove: err %d for iteration %d\n", err, i);
		if (err == 0)
			clear_bit(i, obj_in_table);
	}

	if (ret == 0 && err)
		ret = err;

	for (i = 0; i < entries; i++) {
		WARN(test_bit(i, obj_in_table), "elem %d allegedly still present", i);

		err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
				      test_rht_params);
		if (WARN(err, "error %d on element %d\n", err, i))
			break;
		if (err == 0)
			set_bit(i, obj_in_table);
	}

	pr_info("test %d random rhlist add/delete operations\n", entries);
	for (j = 0; j < entries; j++) {
		u32 i = prandom_u32_max(entries);
		u32 prand = prandom_u32();

		cond_resched();

		if (prand == 0)
			prand = prandom_u32();

		if (prand & 1) {
			prand >>= 1;
			continue;
		}

		err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
		if (test_bit(i, obj_in_table)) {
			clear_bit(i, obj_in_table);
			if (WARN(err, "cannot remove element at slot %d", i))
				continue;
		} else {
			if (WARN(err != -ENOENT, "removed non-existant element %d, error %d not %d",
			     i, err, -ENOENT))
				continue;
		}

		if (prand & 1) {
			prand >>= 1;
			continue;
		}

		err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
		if (err == 0) {
			if (WARN(test_and_set_bit(i, obj_in_table), "succeeded to insert same object %d", i))
				continue;
		} else {
			if (WARN(!test_bit(i, obj_in_table), "failed to insert object %d", i))
				continue;
		}

		if (prand & 1) {
			prand >>= 1;
			continue;
		}

		i = prandom_u32_max(entries);
		if (test_bit(i, obj_in_table)) {
			err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
			WARN(err, "cannot remove element at slot %d", i);
			if (err == 0)
				clear_bit(i, obj_in_table);
		} else {
			err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
			WARN(err, "failed to insert object %d", i);
			if (err == 0)
				set_bit(i, obj_in_table);
		}
	}

	for (i = 0; i < entries; i++) {
		cond_resched();
		err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
		if (test_bit(i, obj_in_table)) {
			if (WARN(err, "cannot remove element at slot %d", i))
				continue;
		} else {
			if (WARN(err != -ENOENT, "removed non-existant element, error %d not %d",
				 err, -ENOENT))
			continue;
		}
	}

	rhltable_destroy(&rhlt);
out_free:
	vfree(rhl_test_objects);
	vfree(obj_in_table);
	return ret;
}

static int __init test_rhashtable_max(struct test_obj *array,
				      unsigned int entries)
{
	unsigned int i, insert_retries = 0;
	int err;

	test_rht_params.max_size = roundup_pow_of_two(entries / 8);
	err = rhashtable_init(&ht, &test_rht_params);
	if (err)
		return err;

	for (i = 0; i < ht.max_elems; i++) {
		struct test_obj *obj = &array[i];

		obj->value.id = i * 2;
		err = insert_retry(&ht, obj, test_rht_params);
		if (err > 0)
			insert_retries += err;
		else if (err)
			return err;
	}

	err = insert_retry(&ht, &array[ht.max_elems], test_rht_params);
	if (err == -E2BIG) {
		err = 0;
	} else {
		pr_info("insert element %u should have failed with %d, got %d\n",
				ht.max_elems, -E2BIG, err);
		if (err == 0)
			err = -1;
	}

	rhashtable_destroy(&ht);

	return err;
}

static unsigned int __init print_ht(struct rhltable *rhlt)
{
	struct rhashtable *ht;
	const struct bucket_table *tbl;
	char buff[512] = "";
	unsigned int i, cnt = 0;

	ht = &rhlt->ht;
	/* Take the mutex to avoid RCU warning */
	mutex_lock(&ht->mutex);
	tbl = rht_dereference(ht->tbl, ht);
	for (i = 0; i < tbl->size; i++) {
		struct rhash_head *pos, *next;
		struct test_obj_rhl *p;

		pos = rht_dereference(tbl->buckets[i], ht);
		next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL;

		if (!rht_is_a_nulls(pos)) {
			sprintf(buff, "%s\nbucket[%d] -> ", buff, i);
		}

		while (!rht_is_a_nulls(pos)) {
			struct rhlist_head *list = container_of(pos, struct rhlist_head, rhead);
			sprintf(buff, "%s[[", buff);
			do {
				pos = &list->rhead;
				list = rht_dereference(list->next, ht);
				p = rht_obj(ht, pos);

				sprintf(buff, "%s val %d (tid=%d)%s", buff, p->value.id, p->value.tid,
					list? ", " : " ");
				cnt++;
			} while (list);

			pos = next,
			next = !rht_is_a_nulls(pos) ?
				rht_dereference(pos->next, ht) : NULL;

			sprintf(buff, "%s]]%s", buff, !rht_is_a_nulls(pos) ? " -> " : "");
		}
	}
	printk(KERN_ERR "\n---- ht: ----%s\n-------------\n", buff);
	mutex_unlock(&ht->mutex);

	return cnt;
}

static int __init test_insert_dup(struct test_obj_rhl *rhl_test_objects,
				  int cnt, bool slow)
{
	struct rhltable *rhlt;
	unsigned int i, ret;
	const char *key;
	int err = 0;

	rhlt = kmalloc(sizeof(*rhlt), GFP_KERNEL);
	if (WARN_ON(!rhlt))
		return -EINVAL;

	err = rhltable_init(rhlt, &test_rht_params_dup);
	if (WARN_ON(err)) {
		kfree(rhlt);
		return err;
	}

	for (i = 0; i < cnt; i++) {
		rhl_test_objects[i].value.tid = i;
		key = rht_obj(&rhlt->ht, &rhl_test_objects[i].list_node.rhead);
		key += test_rht_params_dup.key_offset;

		if (slow) {
			err = PTR_ERR(rhashtable_insert_slow(&rhlt->ht, key,
							     &rhl_test_objects[i].list_node.rhead));
			if (err == -EAGAIN)
				err = 0;
		} else
			err = rhltable_insert(rhlt,
					      &rhl_test_objects[i].list_node,
					      test_rht_params_dup);
		if (WARN(err, "error %d on element %d/%d (%s)\n", err, i, cnt, slow? "slow" : "fast"))
			goto skip_print;
	}

	ret = print_ht(rhlt);
	WARN(ret != cnt, "missing rhltable elements (%d != %d, %s)\n", ret, cnt, slow? "slow" : "fast");

skip_print:
	rhltable_destroy(rhlt);
	kfree(rhlt);

	return 0;
}

static int __init test_insert_duplicates_run(void)
{
	struct test_obj_rhl rhl_test_objects[3] = {};

	pr_info("test inserting duplicates\n");

	/* two different values that map to same bucket */
	rhl_test_objects[0].value.id = 1;
	rhl_test_objects[1].value.id = 21;

	/* and another duplicate with same as [0] value
	 * which will be second on the bucket list */
	rhl_test_objects[2].value.id = rhl_test_objects[0].value.id;

	test_insert_dup(rhl_test_objects, 2, false);
	test_insert_dup(rhl_test_objects, 3, false);
	test_insert_dup(rhl_test_objects, 2, true);
	test_insert_dup(rhl_test_objects, 3, true);

	return 0;
}

static int thread_lookup_test(struct thread_data *tdata)
{
	unsigned int entries = tdata->entries;
	int i, err = 0;

	for (i = 0; i < entries; i++) {
		struct test_obj *obj;
		struct test_obj_val key = {
			.id = i,
			.tid = tdata->id,
		};

		obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
		if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
			pr_err("  found unexpected object %d-%d\n", key.tid, key.id);
			err++;
		} else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
			pr_err("  object %d-%d not found!\n", key.tid, key.id);
			err++;
		} else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
			pr_err("  wrong object returned (got %d-%d, expected %d-%d)\n",
			       obj->value.tid, obj->value.id, key.tid, key.id);
			err++;
		}

		cond_resched();
	}
	return err;
}

static int threadfunc(void *data)
{
	int i, step, err = 0, insert_retries = 0;
	struct thread_data *tdata = data;

	up(&prestart_sem);
	if (down_interruptible(&startup_sem))
		pr_err("  thread[%d]: down_interruptible failed\n", tdata->id);

	for (i = 0; i < tdata->entries; i++) {
		tdata->objs[i].value.id = i;
		tdata->objs[i].value.tid = tdata->id;
		err = insert_retry(&ht, &tdata->objs[i], test_rht_params);
		if (err > 0) {
			insert_retries += err;
		} else if (err) {
			pr_err("  thread[%d]: rhashtable_insert_fast failed\n",
			       tdata->id);
			goto out;
		}
	}
	if (insert_retries)
		pr_info("  thread[%d]: %u insertions retried due to memory pressure\n",
			tdata->id, insert_retries);

	err = thread_lookup_test(tdata);
	if (err) {
		pr_err("  thread[%d]: rhashtable_lookup_test failed\n",
		       tdata->id);
		goto out;
	}

	for (step = 10; step > 0; step--) {
		for (i = 0; i < tdata->entries; i += step) {
			if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
				continue;
			err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
			                             test_rht_params);
			if (err) {
				pr_err("  thread[%d]: rhashtable_remove_fast failed\n",
				       tdata->id);
				goto out;
			}
			tdata->objs[i].value.id = TEST_INSERT_FAIL;

			cond_resched();
		}
		err = thread_lookup_test(tdata);
		if (err) {
			pr_err("  thread[%d]: rhashtable_lookup_test (2) failed\n",
			       tdata->id);
			goto out;
		}
	}
out:
	while (!kthread_should_stop()) {
		set_current_state(TASK_INTERRUPTIBLE);
		schedule();
	}
	return err;
}

static int __init test_rht_init(void)
{
	unsigned int entries;
	int i, err, started_threads = 0, failed_threads = 0;
	u64 total_time = 0;
	struct thread_data *tdata;
	struct test_obj *objs;

	if (parm_entries < 0)
		parm_entries = 1;

	entries = min(parm_entries, MAX_ENTRIES);

	test_rht_params.automatic_shrinking = shrinking;
	test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
	test_rht_params.nelem_hint = size;

	objs = vzalloc(array_size(sizeof(struct test_obj),
				  test_rht_params.max_size + 1));
	if (!objs)
		return -ENOMEM;

	pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
		size, max_size, shrinking);

	for (i = 0; i < runs; i++) {
		s64 time;

		pr_info("Test %02d:\n", i);
		memset(objs, 0, test_rht_params.max_size * sizeof(struct test_obj));

		err = rhashtable_init(&ht, &test_rht_params);
		if (err < 0) {
			pr_warn("Test failed: Unable to initialize hashtable: %d\n",
				err);
			continue;
		}

		time = test_rhashtable(&ht, objs, entries);
		rhashtable_destroy(&ht);
		if (time < 0) {
			vfree(objs);
			pr_warn("Test failed: return code %lld\n", time);
			return -EINVAL;
		}

		total_time += time;
	}

	pr_info("test if its possible to exceed max_size %d: %s\n",
			test_rht_params.max_size, test_rhashtable_max(objs, entries) == 0 ?
			"no, ok" : "YES, failed");
	vfree(objs);

	do_div(total_time, runs);
	pr_info("Average test time: %llu\n", total_time);

	test_insert_duplicates_run();

	if (!tcount)
		return 0;

	pr_info("Testing concurrent rhashtable access from %d threads\n",
	        tcount);
	sema_init(&prestart_sem, 1 - tcount);
	tdata = vzalloc(array_size(tcount, sizeof(struct thread_data)));
	if (!tdata)
		return -ENOMEM;
	objs  = vzalloc(array3_size(sizeof(struct test_obj), tcount, entries));
	if (!objs) {
		vfree(tdata);
		return -ENOMEM;
	}

	test_rht_params.max_size = max_size ? :
	                           roundup_pow_of_two(tcount * entries);
	err = rhashtable_init(&ht, &test_rht_params);
	if (err < 0) {
		pr_warn("Test failed: Unable to initialize hashtable: %d\n",
			err);
		vfree(tdata);
		vfree(objs);
		return -EINVAL;
	}
	for (i = 0; i < tcount; i++) {
		tdata[i].id = i;
		tdata[i].entries = entries;
		tdata[i].objs = objs + i * entries;
		tdata[i].task = kthread_run(threadfunc, &tdata[i],
		                            "rhashtable_thrad[%d]", i);
		if (IS_ERR(tdata[i].task))
			pr_err(" kthread_run failed for thread %d\n", i);
		else
			started_threads++;
	}
	if (down_interruptible(&prestart_sem))
		pr_err("  down interruptible failed\n");
	for (i = 0; i < tcount; i++)
		up(&startup_sem);
	for (i = 0; i < tcount; i++) {
		if (IS_ERR(tdata[i].task))
			continue;
		if ((err = kthread_stop(tdata[i].task))) {
			pr_warn("Test failed: thread %d returned: %d\n",
			        i, err);
			failed_threads++;
		}
	}
	rhashtable_destroy(&ht);
	vfree(tdata);
	vfree(objs);

	/*
	 * rhltable_remove is very expensive, default values can cause test
	 * to run for 2 minutes or more,  use a smaller number instead.
	 */
	err = test_rhltable(entries / 16);
	pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
	        started_threads, failed_threads, err);
	return 0;
}

static void __exit test_rht_exit(void)
{
}

module_init(test_rht_init);
module_exit(test_rht_exit);

MODULE_LICENSE("GPL v2");