summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/vm/ksm_tests.c
blob: fd85f15869d13f755198647280892c4c4bb43e57 (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
// SPDX-License-Identifier: GPL-2.0

#include <sys/mman.h>
#include <stdbool.h>
#include <time.h>
#include <string.h>
#include <numa.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdint.h>
#include <err.h>

#include "../kselftest.h"
#include "../../../../include/vdso/time64.h"
#include "util.h"

#define KSM_SYSFS_PATH "/sys/kernel/mm/ksm/"
#define KSM_FP(s) (KSM_SYSFS_PATH s)
#define KSM_SCAN_LIMIT_SEC_DEFAULT 120
#define KSM_PAGE_COUNT_DEFAULT 10l
#define KSM_PROT_STR_DEFAULT "rw"
#define KSM_USE_ZERO_PAGES_DEFAULT false
#define KSM_MERGE_ACROSS_NODES_DEFAULT true
#define MB (1ul << 20)

struct ksm_sysfs {
	unsigned long max_page_sharing;
	unsigned long merge_across_nodes;
	unsigned long pages_to_scan;
	unsigned long run;
	unsigned long sleep_millisecs;
	unsigned long stable_node_chains_prune_millisecs;
	unsigned long use_zero_pages;
};

enum ksm_test_name {
	CHECK_KSM_MERGE,
	CHECK_KSM_UNMERGE,
	CHECK_KSM_ZERO_PAGE_MERGE,
	CHECK_KSM_NUMA_MERGE,
	KSM_MERGE_TIME,
	KSM_MERGE_TIME_HUGE_PAGES,
	KSM_COW_TIME
};

static int ksm_write_sysfs(const char *file_path, unsigned long val)
{
	FILE *f = fopen(file_path, "w");

	if (!f) {
		fprintf(stderr, "f %s\n", file_path);
		perror("fopen");
		return 1;
	}
	if (fprintf(f, "%lu", val) < 0) {
		perror("fprintf");
		return 1;
	}
	fclose(f);

	return 0;
}

static int ksm_read_sysfs(const char *file_path, unsigned long *val)
{
	FILE *f = fopen(file_path, "r");

	if (!f) {
		fprintf(stderr, "f %s\n", file_path);
		perror("fopen");
		return 1;
	}
	if (fscanf(f, "%lu", val) != 1) {
		perror("fscanf");
		return 1;
	}
	fclose(f);

	return 0;
}

static int str_to_prot(char *prot_str)
{
	int prot = 0;

	if ((strchr(prot_str, 'r')) != NULL)
		prot |= PROT_READ;
	if ((strchr(prot_str, 'w')) != NULL)
		prot |= PROT_WRITE;
	if ((strchr(prot_str, 'x')) != NULL)
		prot |= PROT_EXEC;

	return prot;
}

static void print_help(void)
{
	printf("usage: ksm_tests [-h] <test type> [-a prot] [-p page_count] [-l timeout]\n"
	       "[-z use_zero_pages] [-m merge_across_nodes] [-s size]\n");

	printf("Supported <test type>:\n"
	       " -M (page merging)\n"
	       " -Z (zero pages merging)\n"
	       " -N (merging of pages in different NUMA nodes)\n"
	       " -U (page unmerging)\n"
	       " -P evaluate merging time and speed.\n"
	       "    For this test, the size of duplicated memory area (in MiB)\n"
	       "    must be provided using -s option\n"
				 " -H evaluate merging time and speed of area allocated mostly with huge pages\n"
	       "    For this test, the size of duplicated memory area (in MiB)\n"
	       "    must be provided using -s option\n"
	       " -C evaluate the time required to break COW of merged pages.\n\n");

	printf(" -a: specify the access protections of pages.\n"
	       "     <prot> must be of the form [rwx].\n"
	       "     Default: %s\n", KSM_PROT_STR_DEFAULT);
	printf(" -p: specify the number of pages to test.\n"
	       "     Default: %ld\n", KSM_PAGE_COUNT_DEFAULT);
	printf(" -l: limit the maximum running time (in seconds) for a test.\n"
	       "     Default: %d seconds\n", KSM_SCAN_LIMIT_SEC_DEFAULT);
	printf(" -z: change use_zero_pages tunable\n"
	       "     Default: %d\n", KSM_USE_ZERO_PAGES_DEFAULT);
	printf(" -m: change merge_across_nodes tunable\n"
	       "     Default: %d\n", KSM_MERGE_ACROSS_NODES_DEFAULT);
	printf(" -s: the size of duplicated memory area (in MiB)\n");

	exit(0);
}

static void  *allocate_memory(void *ptr, int prot, int mapping, char data, size_t map_size)
{
	void *map_ptr = mmap(ptr, map_size, PROT_WRITE, mapping, -1, 0);

	if (!map_ptr) {
		perror("mmap");
		return NULL;
	}
	memset(map_ptr, data, map_size);
	if (mprotect(map_ptr, map_size, prot)) {
		perror("mprotect");
		munmap(map_ptr, map_size);
		return NULL;
	}

	return map_ptr;
}

static int ksm_do_scan(int scan_count, struct timespec start_time, int timeout)
{
	struct timespec cur_time;
	unsigned long cur_scan, init_scan;

	if (ksm_read_sysfs(KSM_FP("full_scans"), &init_scan))
		return 1;
	cur_scan = init_scan;

	while (cur_scan < init_scan + scan_count) {
		if (ksm_read_sysfs(KSM_FP("full_scans"), &cur_scan))
			return 1;
		if (clock_gettime(CLOCK_MONOTONIC_RAW, &cur_time)) {
			perror("clock_gettime");
			return 1;
		}
		if ((cur_time.tv_sec - start_time.tv_sec) > timeout) {
			printf("Scan time limit exceeded\n");
			return 1;
		}
	}

	return 0;
}

static int ksm_merge_pages(void *addr, size_t size, struct timespec start_time, int timeout)
{
	if (madvise(addr, size, MADV_MERGEABLE)) {
		perror("madvise");
		return 1;
	}
	if (ksm_write_sysfs(KSM_FP("run"), 1))
		return 1;

	/* Since merging occurs only after 2 scans, make sure to get at least 2 full scans */
	if (ksm_do_scan(2, start_time, timeout))
		return 1;

	return 0;
}

static bool assert_ksm_pages_count(long dupl_page_count)
{
	unsigned long max_page_sharing, pages_sharing, pages_shared;

	if (ksm_read_sysfs(KSM_FP("pages_shared"), &pages_shared) ||
	    ksm_read_sysfs(KSM_FP("pages_sharing"), &pages_sharing) ||
	    ksm_read_sysfs(KSM_FP("max_page_sharing"), &max_page_sharing))
		return false;

	/*
	 * Since there must be at least 2 pages for merging and 1 page can be
	 * shared with the limited number of pages (max_page_sharing), sometimes
	 * there are 'leftover' pages that cannot be merged. For example, if there
	 * are 11 pages and max_page_sharing = 10, then only 10 pages will be
	 * merged and the 11th page won't be affected. As a result, when the number
	 * of duplicate pages is divided by max_page_sharing and the remainder is 1,
	 * pages_shared and pages_sharing values will be equal between dupl_page_count
	 * and dupl_page_count - 1.
	 */
	if (dupl_page_count % max_page_sharing == 1 || dupl_page_count % max_page_sharing == 0) {
		if (pages_shared == dupl_page_count / max_page_sharing &&
		    pages_sharing == pages_shared * (max_page_sharing - 1))
			return true;
	} else {
		if (pages_shared == (dupl_page_count / max_page_sharing + 1) &&
		    pages_sharing == dupl_page_count - pages_shared)
			return true;
	}

	return false;
}

static int ksm_save_def(struct ksm_sysfs *ksm_sysfs)
{
	if (ksm_read_sysfs(KSM_FP("max_page_sharing"), &ksm_sysfs->max_page_sharing) ||
	    ksm_read_sysfs(KSM_FP("merge_across_nodes"), &ksm_sysfs->merge_across_nodes) ||
	    ksm_read_sysfs(KSM_FP("sleep_millisecs"), &ksm_sysfs->sleep_millisecs) ||
	    ksm_read_sysfs(KSM_FP("pages_to_scan"), &ksm_sysfs->pages_to_scan) ||
	    ksm_read_sysfs(KSM_FP("run"), &ksm_sysfs->run) ||
	    ksm_read_sysfs(KSM_FP("stable_node_chains_prune_millisecs"),
			   &ksm_sysfs->stable_node_chains_prune_millisecs) ||
	    ksm_read_sysfs(KSM_FP("use_zero_pages"), &ksm_sysfs->use_zero_pages))
		return 1;

	return 0;
}

static int ksm_restore(struct ksm_sysfs *ksm_sysfs)
{
	if (ksm_write_sysfs(KSM_FP("max_page_sharing"), ksm_sysfs->max_page_sharing) ||
	    ksm_write_sysfs(KSM_FP("merge_across_nodes"), ksm_sysfs->merge_across_nodes) ||
	    ksm_write_sysfs(KSM_FP("pages_to_scan"), ksm_sysfs->pages_to_scan) ||
	    ksm_write_sysfs(KSM_FP("run"), ksm_sysfs->run) ||
	    ksm_write_sysfs(KSM_FP("sleep_millisecs"), ksm_sysfs->sleep_millisecs) ||
	    ksm_write_sysfs(KSM_FP("stable_node_chains_prune_millisecs"),
			    ksm_sysfs->stable_node_chains_prune_millisecs) ||
	    ksm_write_sysfs(KSM_FP("use_zero_pages"), ksm_sysfs->use_zero_pages))
		return 1;

	return 0;
}

static int check_ksm_merge(int mapping, int prot, long page_count, int timeout, size_t page_size)
{
	void *map_ptr;
	struct timespec start_time;

	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
		perror("clock_gettime");
		return KSFT_FAIL;
	}

	/* fill pages with the same data and merge them */
	map_ptr = allocate_memory(NULL, prot, mapping, '*', page_size * page_count);
	if (!map_ptr)
		return KSFT_FAIL;

	if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout))
		goto err_out;

	/* verify that the right number of pages are merged */
	if (assert_ksm_pages_count(page_count)) {
		printf("OK\n");
		munmap(map_ptr, page_size * page_count);
		return KSFT_PASS;
	}

err_out:
	printf("Not OK\n");
	munmap(map_ptr, page_size * page_count);
	return KSFT_FAIL;
}

static int check_ksm_unmerge(int mapping, int prot, int timeout, size_t page_size)
{
	void *map_ptr;
	struct timespec start_time;
	int page_count = 2;

	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
		perror("clock_gettime");
		return KSFT_FAIL;
	}

	/* fill pages with the same data and merge them */
	map_ptr = allocate_memory(NULL, prot, mapping, '*', page_size * page_count);
	if (!map_ptr)
		return KSFT_FAIL;

	if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout))
		goto err_out;

	/* change 1 byte in each of the 2 pages -- KSM must automatically unmerge them */
	memset(map_ptr, '-', 1);
	memset(map_ptr + page_size, '+', 1);

	/* get at least 1 scan, so KSM can detect that the pages were modified */
	if (ksm_do_scan(1, start_time, timeout))
		goto err_out;

	/* check that unmerging was successful and 0 pages are currently merged */
	if (assert_ksm_pages_count(0)) {
		printf("OK\n");
		munmap(map_ptr, page_size * page_count);
		return KSFT_PASS;
	}

err_out:
	printf("Not OK\n");
	munmap(map_ptr, page_size * page_count);
	return KSFT_FAIL;
}

static int check_ksm_zero_page_merge(int mapping, int prot, long page_count, int timeout,
				     bool use_zero_pages, size_t page_size)
{
	void *map_ptr;
	struct timespec start_time;

	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
		perror("clock_gettime");
		return KSFT_FAIL;
	}

	if (ksm_write_sysfs(KSM_FP("use_zero_pages"), use_zero_pages))
		return KSFT_FAIL;

	/* fill pages with zero and try to merge them */
	map_ptr = allocate_memory(NULL, prot, mapping, 0, page_size * page_count);
	if (!map_ptr)
		return KSFT_FAIL;

	if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout))
		goto err_out;

       /*
	* verify that the right number of pages are merged:
	* 1) if use_zero_pages is set to 1, empty pages are merged
	*    with the kernel zero page instead of with each other;
	* 2) if use_zero_pages is set to 0, empty pages are not treated specially
	*    and merged as usual.
	*/
	if (use_zero_pages && !assert_ksm_pages_count(0))
		goto err_out;
	else if (!use_zero_pages && !assert_ksm_pages_count(page_count))
		goto err_out;

	printf("OK\n");
	munmap(map_ptr, page_size * page_count);
	return KSFT_PASS;

err_out:
	printf("Not OK\n");
	munmap(map_ptr, page_size * page_count);
	return KSFT_FAIL;
}

static int get_next_mem_node(int node)
{

	long node_size;
	int mem_node = 0;
	int i, max_node = numa_max_node();

	for (i = node + 1; i <= max_node + node; i++) {
		mem_node = i % (max_node + 1);
		node_size = numa_node_size(mem_node, NULL);
		if (node_size > 0)
			break;
	}
	return mem_node;
}

static int get_first_mem_node(void)
{
	return get_next_mem_node(numa_max_node());
}

static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_across_nodes,
				size_t page_size)
{
	void *numa1_map_ptr, *numa2_map_ptr;
	struct timespec start_time;
	int page_count = 2;
	int first_node;

	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
		perror("clock_gettime");
		return KSFT_FAIL;
	}

	if (numa_available() < 0) {
		perror("NUMA support not enabled");
		return KSFT_SKIP;
	}
	if (numa_num_configured_nodes() <= 1) {
		printf("At least 2 NUMA nodes must be available\n");
		return KSFT_SKIP;
	}
	if (ksm_write_sysfs(KSM_FP("merge_across_nodes"), merge_across_nodes))
		return KSFT_FAIL;

	/* allocate 2 pages in 2 different NUMA nodes and fill them with the same data */
	first_node = get_first_mem_node();
	numa1_map_ptr = numa_alloc_onnode(page_size, first_node);
	numa2_map_ptr = numa_alloc_onnode(page_size, get_next_mem_node(first_node));
	if (!numa1_map_ptr || !numa2_map_ptr) {
		perror("numa_alloc_onnode");
		return KSFT_FAIL;
	}

	memset(numa1_map_ptr, '*', page_size);
	memset(numa2_map_ptr, '*', page_size);

	/* try to merge the pages */
	if (ksm_merge_pages(numa1_map_ptr, page_size, start_time, timeout) ||
	    ksm_merge_pages(numa2_map_ptr, page_size, start_time, timeout))
		goto err_out;

       /*
	* verify that the right number of pages are merged:
	* 1) if merge_across_nodes was enabled, 2 duplicate pages will be merged;
	* 2) if merge_across_nodes = 0, there must be 0 merged pages, since there is
	*    only 1 unique page in each node and they can't be shared.
	*/
	if (merge_across_nodes && !assert_ksm_pages_count(page_count))
		goto err_out;
	else if (!merge_across_nodes && !assert_ksm_pages_count(0))
		goto err_out;

	numa_free(numa1_map_ptr, page_size);
	numa_free(numa2_map_ptr, page_size);
	printf("OK\n");
	return KSFT_PASS;

err_out:
	numa_free(numa1_map_ptr, page_size);
	numa_free(numa2_map_ptr, page_size);
	printf("Not OK\n");
	return KSFT_FAIL;
}

static int ksm_merge_hugepages_time(int mapping, int prot, int timeout, size_t map_size)
{
	void *map_ptr, *map_ptr_orig;
	struct timespec start_time, end_time;
	unsigned long scan_time_ns;
	int pagemap_fd, n_normal_pages, n_huge_pages;

	map_size *= MB;
	size_t len = map_size;

	len -= len % HPAGE_SIZE;
	map_ptr_orig = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE,
			MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
	map_ptr = map_ptr_orig + HPAGE_SIZE - (uintptr_t)map_ptr_orig % HPAGE_SIZE;

	if (map_ptr_orig == MAP_FAILED)
		err(2, "initial mmap");

	if (madvise(map_ptr, len + HPAGE_SIZE, MADV_HUGEPAGE))
		err(2, "MADV_HUGEPAGE");

	pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
	if (pagemap_fd < 0)
		err(2, "open pagemap");

	n_normal_pages = 0;
	n_huge_pages = 0;
	for (void *p = map_ptr; p < map_ptr + len; p += HPAGE_SIZE) {
		if (allocate_transhuge(p, pagemap_fd) < 0)
			n_normal_pages++;
		else
			n_huge_pages++;
	}
	printf("Number of normal pages:    %d\n", n_normal_pages);
	printf("Number of huge pages:    %d\n", n_huge_pages);

	memset(map_ptr, '*', len);

	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
		perror("clock_gettime");
		goto err_out;
	}
	if (ksm_merge_pages(map_ptr, map_size, start_time, timeout))
		goto err_out;
	if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) {
		perror("clock_gettime");
		goto err_out;
	}

	scan_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC +
		       (end_time.tv_nsec - start_time.tv_nsec);

	printf("Total size:    %lu MiB\n", map_size / MB);
	printf("Total time:    %ld.%09ld s\n", scan_time_ns / NSEC_PER_SEC,
	       scan_time_ns % NSEC_PER_SEC);
	printf("Average speed:  %.3f MiB/s\n", (map_size / MB) /
					       ((double)scan_time_ns / NSEC_PER_SEC));

	munmap(map_ptr_orig, len + HPAGE_SIZE);
	return KSFT_PASS;

err_out:
	printf("Not OK\n");
	munmap(map_ptr_orig, len + HPAGE_SIZE);
	return KSFT_FAIL;
}

static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size)
{
	void *map_ptr;
	struct timespec start_time, end_time;
	unsigned long scan_time_ns;

	map_size *= MB;

	map_ptr = allocate_memory(NULL, prot, mapping, '*', map_size);
	if (!map_ptr)
		return KSFT_FAIL;

	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
		perror("clock_gettime");
		goto err_out;
	}
	if (ksm_merge_pages(map_ptr, map_size, start_time, timeout))
		goto err_out;
	if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) {
		perror("clock_gettime");
		goto err_out;
	}

	scan_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC +
		       (end_time.tv_nsec - start_time.tv_nsec);

	printf("Total size:    %lu MiB\n", map_size / MB);
	printf("Total time:    %ld.%09ld s\n", scan_time_ns / NSEC_PER_SEC,
	       scan_time_ns % NSEC_PER_SEC);
	printf("Average speed:  %.3f MiB/s\n", (map_size / MB) /
					       ((double)scan_time_ns / NSEC_PER_SEC));

	munmap(map_ptr, map_size);
	return KSFT_PASS;

err_out:
	printf("Not OK\n");
	munmap(map_ptr, map_size);
	return KSFT_FAIL;
}

static int ksm_cow_time(int mapping, int prot, int timeout, size_t page_size)
{
	void *map_ptr;
	struct timespec start_time, end_time;
	unsigned long cow_time_ns;

	/* page_count must be less than 2*page_size */
	size_t page_count = 4000;

	map_ptr = allocate_memory(NULL, prot, mapping, '*', page_size * page_count);
	if (!map_ptr)
		return KSFT_FAIL;

	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
		perror("clock_gettime");
		return KSFT_FAIL;
	}
	for (size_t i = 0; i < page_count - 1; i = i + 2)
		memset(map_ptr + page_size * i, '-', 1);
	if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) {
		perror("clock_gettime");
		return KSFT_FAIL;
	}

	cow_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC +
		       (end_time.tv_nsec - start_time.tv_nsec);

	printf("Total size:    %lu MiB\n\n", (page_size * page_count) / MB);
	printf("Not merged pages:\n");
	printf("Total time:     %ld.%09ld s\n", cow_time_ns / NSEC_PER_SEC,
	       cow_time_ns % NSEC_PER_SEC);
	printf("Average speed:  %.3f MiB/s\n\n", ((page_size * (page_count / 2)) / MB) /
					       ((double)cow_time_ns / NSEC_PER_SEC));

	/* Create 2000 pairs of duplicate pages */
	for (size_t i = 0; i < page_count - 1; i = i + 2) {
		memset(map_ptr + page_size * i, '+', i / 2 + 1);
		memset(map_ptr + page_size * (i + 1), '+', i / 2 + 1);
	}
	if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout))
		goto err_out;

	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
		perror("clock_gettime");
		goto err_out;
	}
	for (size_t i = 0; i < page_count - 1; i = i + 2)
		memset(map_ptr + page_size * i, '-', 1);
	if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) {
		perror("clock_gettime");
		goto err_out;
	}

	cow_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC +
		       (end_time.tv_nsec - start_time.tv_nsec);

	printf("Merged pages:\n");
	printf("Total time:     %ld.%09ld s\n", cow_time_ns / NSEC_PER_SEC,
	       cow_time_ns % NSEC_PER_SEC);
	printf("Average speed:  %.3f MiB/s\n", ((page_size * (page_count / 2)) / MB) /
					       ((double)cow_time_ns / NSEC_PER_SEC));

	munmap(map_ptr, page_size * page_count);
	return KSFT_PASS;

err_out:
	printf("Not OK\n");
	munmap(map_ptr, page_size * page_count);
	return KSFT_FAIL;
}

int main(int argc, char *argv[])
{
	int ret, opt;
	int prot = 0;
	int ksm_scan_limit_sec = KSM_SCAN_LIMIT_SEC_DEFAULT;
	long page_count = KSM_PAGE_COUNT_DEFAULT;
	size_t page_size = sysconf(_SC_PAGESIZE);
	struct ksm_sysfs ksm_sysfs_old;
	int test_name = CHECK_KSM_MERGE;
	bool use_zero_pages = KSM_USE_ZERO_PAGES_DEFAULT;
	bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT;
	long size_MB = 0;

	while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNPCH")) != -1) {
		switch (opt) {
		case 'a':
			prot = str_to_prot(optarg);
			break;
		case 'p':
			page_count = atol(optarg);
			if (page_count <= 0) {
				printf("The number of pages must be greater than 0\n");
				return KSFT_FAIL;
			}
			break;
		case 'l':
			ksm_scan_limit_sec = atoi(optarg);
			if (ksm_scan_limit_sec <= 0) {
				printf("Timeout value must be greater than 0\n");
				return KSFT_FAIL;
			}
			break;
		case 'h':
			print_help();
			break;
		case 'z':
			if (strcmp(optarg, "0") == 0)
				use_zero_pages = 0;
			else
				use_zero_pages = 1;
			break;
		case 'm':
			if (strcmp(optarg, "0") == 0)
				merge_across_nodes = 0;
			else
				merge_across_nodes = 1;
			break;
		case 's':
			size_MB = atoi(optarg);
			if (size_MB <= 0) {
				printf("Size must be greater than 0\n");
				return KSFT_FAIL;
			}
		case 'M':
			break;
		case 'U':
			test_name = CHECK_KSM_UNMERGE;
			break;
		case 'Z':
			test_name = CHECK_KSM_ZERO_PAGE_MERGE;
			break;
		case 'N':
			test_name = CHECK_KSM_NUMA_MERGE;
			break;
		case 'P':
			test_name = KSM_MERGE_TIME;
			break;
		case 'H':
			test_name = KSM_MERGE_TIME_HUGE_PAGES;
			break;
		case 'C':
			test_name = KSM_COW_TIME;
			break;
		default:
			return KSFT_FAIL;
		}
	}

	if (prot == 0)
		prot = str_to_prot(KSM_PROT_STR_DEFAULT);

	if (access(KSM_SYSFS_PATH, F_OK)) {
		printf("Config KSM not enabled\n");
		return KSFT_SKIP;
	}

	if (ksm_save_def(&ksm_sysfs_old)) {
		printf("Cannot save default tunables\n");
		return KSFT_FAIL;
	}

	if (ksm_write_sysfs(KSM_FP("run"), 2) ||
	    ksm_write_sysfs(KSM_FP("sleep_millisecs"), 0) ||
	    ksm_write_sysfs(KSM_FP("merge_across_nodes"), 1) ||
	    ksm_write_sysfs(KSM_FP("pages_to_scan"), page_count))
		return KSFT_FAIL;

	switch (test_name) {
	case CHECK_KSM_MERGE:
		ret = check_ksm_merge(MAP_PRIVATE | MAP_ANONYMOUS, prot, page_count,
				      ksm_scan_limit_sec, page_size);
		break;
	case CHECK_KSM_UNMERGE:
		ret = check_ksm_unmerge(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
					page_size);
		break;
	case CHECK_KSM_ZERO_PAGE_MERGE:
		ret = check_ksm_zero_page_merge(MAP_PRIVATE | MAP_ANONYMOUS, prot, page_count,
						ksm_scan_limit_sec, use_zero_pages, page_size);
		break;
	case CHECK_KSM_NUMA_MERGE:
		ret = check_ksm_numa_merge(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
					   merge_across_nodes, page_size);
		break;
	case KSM_MERGE_TIME:
		if (size_MB == 0) {
			printf("Option '-s' is required.\n");
			return KSFT_FAIL;
		}
		ret = ksm_merge_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
				     size_MB);
		break;
	case KSM_MERGE_TIME_HUGE_PAGES:
		if (size_MB == 0) {
			printf("Option '-s' is required.\n");
			return KSFT_FAIL;
		}
		ret = ksm_merge_hugepages_time(MAP_PRIVATE | MAP_ANONYMOUS, prot,
				ksm_scan_limit_sec, size_MB);
		break;
	case KSM_COW_TIME:
		ret = ksm_cow_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
				   page_size);
		break;
	}

	if (ksm_restore(&ksm_sysfs_old)) {
		printf("Cannot restore default tunables\n");
		return KSFT_FAIL;
	}

	return ret;
}