summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/ttm/ttm_page_alloc.c
blob: 2c28c4568c5f3eeec0f6899ee99a19f8beff2da9 (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
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
/*
 * Copyright (c) Red Hat Inc.

 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sub license,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Authors: Dave Airlie <airlied@redhat.com>
 *          Jerome Glisse <jglisse@redhat.com>
 *          Pauli Nieminen <suokkos@gmail.com>
 */

/* simple list based uncached page pool
 * - Pool collects resently freed pages for reuse
 * - Use page->lru to keep a free list
 * - doesn't track currently in use pages
 */

#define pr_fmt(fmt) "[TTM] " fmt

#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/highmem.h>
#include <linux/mm_types.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/seq_file.h> /* for seq_printf */
#include <linux/slab.h>
#include <linux/dma-mapping.h>

#include <linux/atomic.h>

#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_page_alloc.h>

#if IS_ENABLED(CONFIG_AGP)
#include <asm/agp.h>
#endif
#ifdef CONFIG_X86
#include <asm/set_memory.h>
#endif

#define NUM_PAGES_TO_ALLOC		(PAGE_SIZE/sizeof(struct page *))
#define SMALL_ALLOCATION		16
#define FREE_ALL_PAGES			(~0U)
/* times are in msecs */
#define PAGE_FREE_INTERVAL		1000

/**
 * struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
 *
 * @lock: Protects the shared pool from concurrnet access. Must be used with
 * irqsave/irqrestore variants because pool allocator maybe called from
 * delayed work.
 * @fill_lock: Prevent concurrent calls to fill.
 * @list: Pool of free uc/wc pages for fast reuse.
 * @gfp_flags: Flags to pass for alloc_page.
 * @npages: Number of pages in pool.
 */
struct ttm_page_pool {
	spinlock_t		lock;
	bool			fill_lock;
	struct list_head	list;
	gfp_t			gfp_flags;
	unsigned		npages;
	char			*name;
	unsigned long		nfrees;
	unsigned long		nrefills;
	unsigned int		order;
};

/**
 * Limits for the pool. They are handled without locks because only place where
 * they may change is in sysfs store. They won't have immediate effect anyway
 * so forcing serialization to access them is pointless.
 */

struct ttm_pool_opts {
	unsigned	alloc_size;
	unsigned	max_size;
	unsigned	small;
};

#define NUM_POOLS 6

/**
 * struct ttm_pool_manager - Holds memory pools for fst allocation
 *
 * Manager is read only object for pool code so it doesn't need locking.
 *
 * @free_interval: minimum number of jiffies between freeing pages from pool.
 * @page_alloc_inited: reference counting for pool allocation.
 * @work: Work that is used to shrink the pool. Work is only run when there is
 * some pages to free.
 * @small_allocation: Limit in number of pages what is small allocation.
 *
 * @pools: All pool objects in use.
 **/
struct ttm_pool_manager {
	struct kobject		kobj;
	struct shrinker		mm_shrink;
	struct ttm_pool_opts	options;

	union {
		struct ttm_page_pool	pools[NUM_POOLS];
		struct {
			struct ttm_page_pool	wc_pool;
			struct ttm_page_pool	uc_pool;
			struct ttm_page_pool	wc_pool_dma32;
			struct ttm_page_pool	uc_pool_dma32;
			struct ttm_page_pool	wc_pool_huge;
			struct ttm_page_pool	uc_pool_huge;
		} ;
	};
};

static struct attribute ttm_page_pool_max = {
	.name = "pool_max_size",
	.mode = S_IRUGO | S_IWUSR
};
static struct attribute ttm_page_pool_small = {
	.name = "pool_small_allocation",
	.mode = S_IRUGO | S_IWUSR
};
static struct attribute ttm_page_pool_alloc_size = {
	.name = "pool_allocation_size",
	.mode = S_IRUGO | S_IWUSR
};

static struct attribute *ttm_pool_attrs[] = {
	&ttm_page_pool_max,
	&ttm_page_pool_small,
	&ttm_page_pool_alloc_size,
	NULL
};

static void ttm_pool_kobj_release(struct kobject *kobj)
{
	struct ttm_pool_manager *m =
		container_of(kobj, struct ttm_pool_manager, kobj);
	kfree(m);
}

static ssize_t ttm_pool_store(struct kobject *kobj,
		struct attribute *attr, const char *buffer, size_t size)
{
	struct ttm_pool_manager *m =
		container_of(kobj, struct ttm_pool_manager, kobj);
	int chars;
	unsigned val;
	chars = sscanf(buffer, "%u", &val);
	if (chars == 0)
		return size;

	/* Convert kb to number of pages */
	val = val / (PAGE_SIZE >> 10);

	if (attr == &ttm_page_pool_max)
		m->options.max_size = val;
	else if (attr == &ttm_page_pool_small)
		m->options.small = val;
	else if (attr == &ttm_page_pool_alloc_size) {
		if (val > NUM_PAGES_TO_ALLOC*8) {
			pr_err("Setting allocation size to %lu is not allowed. Recommended size is %lu\n",
			       NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
			       NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
			return size;
		} else if (val > NUM_PAGES_TO_ALLOC) {
			pr_warn("Setting allocation size to larger than %lu is not recommended\n",
				NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
		}
		m->options.alloc_size = val;
	}

	return size;
}

static ssize_t ttm_pool_show(struct kobject *kobj,
		struct attribute *attr, char *buffer)
{
	struct ttm_pool_manager *m =
		container_of(kobj, struct ttm_pool_manager, kobj);
	unsigned val = 0;

	if (attr == &ttm_page_pool_max)
		val = m->options.max_size;
	else if (attr == &ttm_page_pool_small)
		val = m->options.small;
	else if (attr == &ttm_page_pool_alloc_size)
		val = m->options.alloc_size;

	val = val * (PAGE_SIZE >> 10);

	return snprintf(buffer, PAGE_SIZE, "%u\n", val);
}

static const struct sysfs_ops ttm_pool_sysfs_ops = {
	.show = &ttm_pool_show,
	.store = &ttm_pool_store,
};

static struct kobj_type ttm_pool_kobj_type = {
	.release = &ttm_pool_kobj_release,
	.sysfs_ops = &ttm_pool_sysfs_ops,
	.default_attrs = ttm_pool_attrs,
};

static struct ttm_pool_manager *_manager;

#ifndef CONFIG_X86
static int set_pages_wb(struct page *page, int numpages)
{
#if IS_ENABLED(CONFIG_AGP)
	int i;

	for (i = 0; i < numpages; i++)
		unmap_page_from_agp(page++);
#endif
	return 0;
}

static int set_pages_array_wb(struct page **pages, int addrinarray)
{
#if IS_ENABLED(CONFIG_AGP)
	int i;

	for (i = 0; i < addrinarray; i++)
		unmap_page_from_agp(pages[i]);
#endif
	return 0;
}

static int set_pages_array_wc(struct page **pages, int addrinarray)
{
#if IS_ENABLED(CONFIG_AGP)
	int i;

	for (i = 0; i < addrinarray; i++)
		map_page_into_agp(pages[i]);
#endif
	return 0;
}

static int set_pages_array_uc(struct page **pages, int addrinarray)
{
#if IS_ENABLED(CONFIG_AGP)
	int i;

	for (i = 0; i < addrinarray; i++)
		map_page_into_agp(pages[i]);
#endif
	return 0;
}
#endif

/**
 * Select the right pool or requested caching state and ttm flags. */
static struct ttm_page_pool *ttm_get_pool(int flags, bool huge,
					  enum ttm_caching_state cstate)
{
	int pool_index;

	if (cstate == tt_cached)
		return NULL;

	if (cstate == tt_wc)
		pool_index = 0x0;
	else
		pool_index = 0x1;

	if (flags & TTM_PAGE_FLAG_DMA32) {
		if (huge)
			return NULL;
		pool_index |= 0x2;

	} else if (huge) {
		pool_index |= 0x4;
	}

	return &_manager->pools[pool_index];
}

/* set memory back to wb and free the pages. */
static void ttm_pages_put(struct page *pages[], unsigned npages,
		unsigned int order)
{
	unsigned int i, pages_nr = (1 << order);

	if (order == 0) {
		if (set_pages_array_wb(pages, npages))
			pr_err("Failed to set %d pages to wb!\n", npages);
	}

	for (i = 0; i < npages; ++i) {
		if (order > 0) {
			if (set_pages_wb(pages[i], pages_nr))
				pr_err("Failed to set %d pages to wb!\n", pages_nr);
		}
		__free_pages(pages[i], order);
	}
}

static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
		unsigned freed_pages)
{
	pool->npages -= freed_pages;
	pool->nfrees += freed_pages;
}

/**
 * Free pages from pool.
 *
 * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
 * number of pages in one go.
 *
 * @pool: to free the pages from
 * @free_all: If set to true will free all pages in pool
 * @use_static: Safe to use static buffer
 **/
static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free,
			      bool use_static)
{
	static struct page *static_buf[NUM_PAGES_TO_ALLOC];
	unsigned long irq_flags;
	struct page *p;
	struct page **pages_to_free;
	unsigned freed_pages = 0,
		 npages_to_free = nr_free;

	if (NUM_PAGES_TO_ALLOC < nr_free)
		npages_to_free = NUM_PAGES_TO_ALLOC;

	if (use_static)
		pages_to_free = static_buf;
	else
		pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
					GFP_KERNEL);
	if (!pages_to_free) {
		pr_debug("Failed to allocate memory for pool free operation\n");
		return 0;
	}

restart:
	spin_lock_irqsave(&pool->lock, irq_flags);

	list_for_each_entry_reverse(p, &pool->list, lru) {
		if (freed_pages >= npages_to_free)
			break;

		pages_to_free[freed_pages++] = p;
		/* We can only remove NUM_PAGES_TO_ALLOC at a time. */
		if (freed_pages >= NUM_PAGES_TO_ALLOC) {
			/* remove range of pages from the pool */
			__list_del(p->lru.prev, &pool->list);

			ttm_pool_update_free_locked(pool, freed_pages);
			/**
			 * Because changing page caching is costly
			 * we unlock the pool to prevent stalling.
			 */
			spin_unlock_irqrestore(&pool->lock, irq_flags);

			ttm_pages_put(pages_to_free, freed_pages, pool->order);
			if (likely(nr_free != FREE_ALL_PAGES))
				nr_free -= freed_pages;

			if (NUM_PAGES_TO_ALLOC >= nr_free)
				npages_to_free = nr_free;
			else
				npages_to_free = NUM_PAGES_TO_ALLOC;

			freed_pages = 0;

			/* free all so restart the processing */
			if (nr_free)
				goto restart;

			/* Not allowed to fall through or break because
			 * following context is inside spinlock while we are
			 * outside here.
			 */
			goto out;

		}
	}

	/* remove range of pages from the pool */
	if (freed_pages) {
		__list_del(&p->lru, &pool->list);

		ttm_pool_update_free_locked(pool, freed_pages);
		nr_free -= freed_pages;
	}

	spin_unlock_irqrestore(&pool->lock, irq_flags);

	if (freed_pages)
		ttm_pages_put(pages_to_free, freed_pages, pool->order);
out:
	if (pages_to_free != static_buf)
		kfree(pages_to_free);
	return nr_free;
}

/**
 * Callback for mm to request pool to reduce number of page held.
 *
 * XXX: (dchinner) Deadlock warning!
 *
 * This code is crying out for a shrinker per pool....
 */
static unsigned long
ttm_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
{
	static DEFINE_MUTEX(lock);
	static unsigned start_pool;
	unsigned i;
	unsigned pool_offset;
	struct ttm_page_pool *pool;
	int shrink_pages = sc->nr_to_scan;
	unsigned long freed = 0;
	unsigned int nr_free_pool;

	if (!mutex_trylock(&lock))
		return SHRINK_STOP;
	pool_offset = ++start_pool % NUM_POOLS;
	/* select start pool in round robin fashion */
	for (i = 0; i < NUM_POOLS; ++i) {
		unsigned nr_free = shrink_pages;
		unsigned page_nr;

		if (shrink_pages == 0)
			break;

		pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
		page_nr = (1 << pool->order);
		/* OK to use static buffer since global mutex is held. */
		nr_free_pool = roundup(nr_free, page_nr) >> pool->order;
		shrink_pages = ttm_page_pool_free(pool, nr_free_pool, true);
		freed += (nr_free_pool - shrink_pages) << pool->order;
		if (freed >= sc->nr_to_scan)
			break;
		shrink_pages <<= pool->order;
	}
	mutex_unlock(&lock);
	return freed;
}


static unsigned long
ttm_pool_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
{
	unsigned i;
	unsigned long count = 0;
	struct ttm_page_pool *pool;

	for (i = 0; i < NUM_POOLS; ++i) {
		pool = &_manager->pools[i];
		count += (pool->npages << pool->order);
	}

	return count;
}

static int ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
{
	manager->mm_shrink.count_objects = ttm_pool_shrink_count;
	manager->mm_shrink.scan_objects = ttm_pool_shrink_scan;
	manager->mm_shrink.seeks = 1;
	return register_shrinker(&manager->mm_shrink);
}

static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
{
	unregister_shrinker(&manager->mm_shrink);
}

static int ttm_set_pages_caching(struct page **pages,
		enum ttm_caching_state cstate, unsigned cpages)
{
	int r = 0;
	/* Set page caching */
	switch (cstate) {
	case tt_uncached:
		r = set_pages_array_uc(pages, cpages);
		if (r)
			pr_err("Failed to set %d pages to uc!\n", cpages);
		break;
	case tt_wc:
		r = set_pages_array_wc(pages, cpages);
		if (r)
			pr_err("Failed to set %d pages to wc!\n", cpages);
		break;
	default:
		break;
	}
	return r;
}

/**
 * Free pages the pages that failed to change the caching state. If there is
 * any pages that have changed their caching state already put them to the
 * pool.
 */
static void ttm_handle_caching_state_failure(struct list_head *pages,
		int ttm_flags, enum ttm_caching_state cstate,
		struct page **failed_pages, unsigned cpages)
{
	unsigned i;
	/* Failed pages have to be freed */
	for (i = 0; i < cpages; ++i) {
		list_del(&failed_pages[i]->lru);
		__free_page(failed_pages[i]);
	}
}

/**
 * Allocate new pages with correct caching.
 *
 * This function is reentrant if caller updates count depending on number of
 * pages returned in pages array.
 */
static int ttm_alloc_new_pages(struct list_head *pages, gfp_t gfp_flags,
			       int ttm_flags, enum ttm_caching_state cstate,
			       unsigned count, unsigned order)
{
	struct page **caching_array;
	struct page *p;
	int r = 0;
	unsigned i, j, cpages;
	unsigned npages = 1 << order;
	unsigned max_cpages = min(count << order, (unsigned)NUM_PAGES_TO_ALLOC);

	/* allocate array for page caching change */
	caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);

	if (!caching_array) {
		pr_debug("Unable to allocate table for new pages\n");
		return -ENOMEM;
	}

	for (i = 0, cpages = 0; i < count; ++i) {
		p = alloc_pages(gfp_flags, order);

		if (!p) {
			pr_debug("Unable to get page %u\n", i);

			/* store already allocated pages in the pool after
			 * setting the caching state */
			if (cpages) {
				r = ttm_set_pages_caching(caching_array,
							  cstate, cpages);
				if (r)
					ttm_handle_caching_state_failure(pages,
						ttm_flags, cstate,
						caching_array, cpages);
			}
			r = -ENOMEM;
			goto out;
		}

		list_add(&p->lru, pages);

#ifdef CONFIG_HIGHMEM
		/* gfp flags of highmem page should never be dma32 so we
		 * we should be fine in such case
		 */
		if (PageHighMem(p))
			continue;

#endif
		for (j = 0; j < npages; ++j) {
			caching_array[cpages++] = p++;
			if (cpages == max_cpages) {

				r = ttm_set_pages_caching(caching_array,
						cstate, cpages);
				if (r) {
					ttm_handle_caching_state_failure(pages,
						ttm_flags, cstate,
						caching_array, cpages);
					goto out;
				}
				cpages = 0;
			}
		}
	}

	if (cpages) {
		r = ttm_set_pages_caching(caching_array, cstate, cpages);
		if (r)
			ttm_handle_caching_state_failure(pages,
					ttm_flags, cstate,
					caching_array, cpages);
	}
out:
	kfree(caching_array);

	return r;
}

/**
 * Fill the given pool if there aren't enough pages and the requested number of
 * pages is small.
 */
static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool, int ttm_flags,
				      enum ttm_caching_state cstate,
				      unsigned count, unsigned long *irq_flags)
{
	struct page *p;
	int r;
	unsigned cpages = 0;
	/**
	 * Only allow one pool fill operation at a time.
	 * If pool doesn't have enough pages for the allocation new pages are
	 * allocated from outside of pool.
	 */
	if (pool->fill_lock)
		return;

	pool->fill_lock = true;

	/* If allocation request is small and there are not enough
	 * pages in a pool we fill the pool up first. */
	if (count < _manager->options.small
		&& count > pool->npages) {
		struct list_head new_pages;
		unsigned alloc_size = _manager->options.alloc_size;

		/**
		 * Can't change page caching if in irqsave context. We have to
		 * drop the pool->lock.
		 */
		spin_unlock_irqrestore(&pool->lock, *irq_flags);

		INIT_LIST_HEAD(&new_pages);
		r = ttm_alloc_new_pages(&new_pages, pool->gfp_flags, ttm_flags,
					cstate, alloc_size, 0);
		spin_lock_irqsave(&pool->lock, *irq_flags);

		if (!r) {
			list_splice(&new_pages, &pool->list);
			++pool->nrefills;
			pool->npages += alloc_size;
		} else {
			pr_debug("Failed to fill pool (%p)\n", pool);
			/* If we have any pages left put them to the pool. */
			list_for_each_entry(p, &new_pages, lru) {
				++cpages;
			}
			list_splice(&new_pages, &pool->list);
			pool->npages += cpages;
		}

	}
	pool->fill_lock = false;
}

/**
 * Allocate pages from the pool and put them on the return list.
 *
 * @return zero for success or negative error code.
 */
static int ttm_page_pool_get_pages(struct ttm_page_pool *pool,
				   struct list_head *pages,
				   int ttm_flags,
				   enum ttm_caching_state cstate,
				   unsigned count, unsigned order)
{
	unsigned long irq_flags;
	struct list_head *p;
	unsigned i;
	int r = 0;

	spin_lock_irqsave(&pool->lock, irq_flags);
	if (!order)
		ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count,
					  &irq_flags);

	if (count >= pool->npages) {
		/* take all pages from the pool */
		list_splice_init(&pool->list, pages);
		count -= pool->npages;
		pool->npages = 0;
		goto out;
	}
	/* find the last pages to include for requested number of pages. Split
	 * pool to begin and halve it to reduce search space. */
	if (count <= pool->npages/2) {
		i = 0;
		list_for_each(p, &pool->list) {
			if (++i == count)
				break;
		}
	} else {
		i = pool->npages + 1;
		list_for_each_prev(p, &pool->list) {
			if (--i == count)
				break;
		}
	}
	/* Cut 'count' number of pages from the pool */
	list_cut_position(pages, &pool->list, p);
	pool->npages -= count;
	count = 0;
out:
	spin_unlock_irqrestore(&pool->lock, irq_flags);

	/* clear the pages coming from the pool if requested */
	if (ttm_flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
		struct page *page;

		list_for_each_entry(page, pages, lru) {
			if (PageHighMem(page))
				clear_highpage(page);
			else
				clear_page(page_address(page));
		}
	}

	/* If pool didn't have enough pages allocate new one. */
	if (count) {
		gfp_t gfp_flags = pool->gfp_flags;

		/* set zero flag for page allocation if required */
		if (ttm_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
			gfp_flags |= __GFP_ZERO;

		if (ttm_flags & TTM_PAGE_FLAG_NO_RETRY)
			gfp_flags |= __GFP_RETRY_MAYFAIL;

		/* ttm_alloc_new_pages doesn't reference pool so we can run
		 * multiple requests in parallel.
		 **/
		r = ttm_alloc_new_pages(pages, gfp_flags, ttm_flags, cstate,
					count, order);
	}

	return r;
}

/* Put all pages in pages list to correct pool to wait for reuse */
static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
			  enum ttm_caching_state cstate)
{
	struct ttm_page_pool *pool = ttm_get_pool(flags, false, cstate);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	struct ttm_page_pool *huge = ttm_get_pool(flags, true, cstate);
#endif
	unsigned long irq_flags;
	unsigned i;

	if (pool == NULL) {
		/* No pool for this memory type so free the pages */
		i = 0;
		while (i < npages) {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
			struct page *p = pages[i];
#endif
			unsigned order = 0, j;

			if (!pages[i]) {
				++i;
				continue;
			}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
			if (!(flags & TTM_PAGE_FLAG_DMA32)) {
				for (j = 0; j < HPAGE_PMD_NR; ++j)
					if (p++ != pages[i + j])
					    break;

				if (j == HPAGE_PMD_NR)
					order = HPAGE_PMD_ORDER;
			}
#endif

			if (page_count(pages[i]) != 1)
				pr_err("Erroneous page count. Leaking pages.\n");
			__free_pages(pages[i], order);

			j = 1 << order;
			while (j) {
				pages[i++] = NULL;
				--j;
			}
		}
		return;
	}

	i = 0;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	if (huge) {
		unsigned max_size, n2free;

		spin_lock_irqsave(&huge->lock, irq_flags);
		while (i < npages) {
			struct page *p = pages[i];
			unsigned j;

			if (!p)
				break;

			for (j = 0; j < HPAGE_PMD_NR; ++j)
				if (p++ != pages[i + j])
				    break;

			if (j != HPAGE_PMD_NR)
				break;

			list_add_tail(&pages[i]->lru, &huge->list);

			for (j = 0; j < HPAGE_PMD_NR; ++j)
				pages[i++] = NULL;
			huge->npages++;
		}

		/* Check that we don't go over the pool limit */
		max_size = _manager->options.max_size;
		max_size /= HPAGE_PMD_NR;
		if (huge->npages > max_size)
			n2free = huge->npages - max_size;
		else
			n2free = 0;
		spin_unlock_irqrestore(&huge->lock, irq_flags);
		if (n2free)
			ttm_page_pool_free(huge, n2free, false);
	}
#endif

	spin_lock_irqsave(&pool->lock, irq_flags);
	while (i < npages) {
		if (pages[i]) {
			if (page_count(pages[i]) != 1)
				pr_err("Erroneous page count. Leaking pages.\n");
			list_add_tail(&pages[i]->lru, &pool->list);
			pages[i] = NULL;
			pool->npages++;
		}
		++i;
	}
	/* Check that we don't go over the pool limit */
	npages = 0;
	if (pool->npages > _manager->options.max_size) {
		npages = pool->npages - _manager->options.max_size;
		/* free at least NUM_PAGES_TO_ALLOC number of pages
		 * to reduce calls to set_memory_wb */
		if (npages < NUM_PAGES_TO_ALLOC)
			npages = NUM_PAGES_TO_ALLOC;
	}
	spin_unlock_irqrestore(&pool->lock, irq_flags);
	if (npages)
		ttm_page_pool_free(pool, npages, false);
}

/*
 * On success pages list will hold count number of correctly
 * cached pages.
 */
static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
			 enum ttm_caching_state cstate)
{
	struct ttm_page_pool *pool = ttm_get_pool(flags, false, cstate);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	struct ttm_page_pool *huge = ttm_get_pool(flags, true, cstate);
#endif
	struct list_head plist;
	struct page *p = NULL;
	unsigned count, first;
	int r;

	/* No pool for cached pages */
	if (pool == NULL) {
		gfp_t gfp_flags = GFP_USER;
		unsigned i;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
		unsigned j;
#endif

		/* set zero flag for page allocation if required */
		if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
			gfp_flags |= __GFP_ZERO;

		if (flags & TTM_PAGE_FLAG_NO_RETRY)
			gfp_flags |= __GFP_RETRY_MAYFAIL;

		if (flags & TTM_PAGE_FLAG_DMA32)
			gfp_flags |= GFP_DMA32;
		else
			gfp_flags |= GFP_HIGHUSER;

		i = 0;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
		if (!(gfp_flags & GFP_DMA32)) {
			while (npages >= HPAGE_PMD_NR) {
				gfp_t huge_flags = gfp_flags;

				huge_flags |= GFP_TRANSHUGE;
				huge_flags &= ~__GFP_MOVABLE;
				huge_flags &= ~__GFP_COMP;
				p = alloc_pages(huge_flags, HPAGE_PMD_ORDER);
				if (!p)
					break;

				for (j = 0; j < HPAGE_PMD_NR; ++j)
					pages[i++] = p++;

				npages -= HPAGE_PMD_NR;
			}
		}
#endif

		first = i;
		while (npages) {
			p = alloc_page(gfp_flags);
			if (!p) {
				pr_debug("Unable to allocate page\n");
				return -ENOMEM;
			}

			/* Swap the pages if we detect consecutive order */
			if (i > first && pages[i - 1] == p - 1)
				swap(p, pages[i - 1]);

			pages[i++] = p;
			--npages;
		}
		return 0;
	}

	count = 0;

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	if (huge && npages >= HPAGE_PMD_NR) {
		INIT_LIST_HEAD(&plist);
		ttm_page_pool_get_pages(huge, &plist, flags, cstate,
					npages / HPAGE_PMD_NR,
					HPAGE_PMD_ORDER);

		list_for_each_entry(p, &plist, lru) {
			unsigned j;

			for (j = 0; j < HPAGE_PMD_NR; ++j)
				pages[count++] = &p[j];
		}
	}
#endif

	INIT_LIST_HEAD(&plist);
	r = ttm_page_pool_get_pages(pool, &plist, flags, cstate,
				    npages - count, 0);

	first = count;
	list_for_each_entry(p, &plist, lru) {
		struct page *tmp = p;

		/* Swap the pages if we detect consecutive order */
		if (count > first && pages[count - 1] == tmp - 1)
			swap(tmp, pages[count - 1]);
		pages[count++] = tmp;
	}

	if (r) {
		/* If there is any pages in the list put them back to
		 * the pool.
		 */
		pr_debug("Failed to allocate extra pages for large request\n");
		ttm_put_pages(pages, count, flags, cstate);
		return r;
	}

	return 0;
}

static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, gfp_t flags,
		char *name, unsigned int order)
{
	spin_lock_init(&pool->lock);
	pool->fill_lock = false;
	INIT_LIST_HEAD(&pool->list);
	pool->npages = pool->nfrees = 0;
	pool->gfp_flags = flags;
	pool->name = name;
	pool->order = order;
}

int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
{
	int ret;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	unsigned order = HPAGE_PMD_ORDER;
#else
	unsigned order = 0;
#endif

	WARN_ON(_manager);

	pr_info("Initializing pool allocator\n");

	_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
	if (!_manager)
		return -ENOMEM;

	ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc", 0);

	ttm_page_pool_init_locked(&_manager->uc_pool, GFP_HIGHUSER, "uc", 0);

	ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
				  GFP_USER | GFP_DMA32, "wc dma", 0);

	ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
				  GFP_USER | GFP_DMA32, "uc dma", 0);

	ttm_page_pool_init_locked(&_manager->wc_pool_huge,
				  GFP_TRANSHUGE	& ~(__GFP_MOVABLE | __GFP_COMP),
				  "wc huge", order);

	ttm_page_pool_init_locked(&_manager->uc_pool_huge,
				  GFP_TRANSHUGE	& ~(__GFP_MOVABLE | __GFP_COMP)
				  , "uc huge", order);

	_manager->options.max_size = max_pages;
	_manager->options.small = SMALL_ALLOCATION;
	_manager->options.alloc_size = NUM_PAGES_TO_ALLOC;

	ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
				   &glob->kobj, "pool");
	if (unlikely(ret != 0))
		goto error;

	ret = ttm_pool_mm_shrink_init(_manager);
	if (unlikely(ret != 0))
		goto error;
	return 0;

error:
	kobject_put(&_manager->kobj);
	_manager = NULL;
	return ret;
}

void ttm_page_alloc_fini(void)
{
	int i;

	pr_info("Finalizing pool allocator\n");
	ttm_pool_mm_shrink_fini(_manager);

	/* OK to use static buffer since global mutex is no longer used. */
	for (i = 0; i < NUM_POOLS; ++i)
		ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES, true);

	kobject_put(&_manager->kobj);
	_manager = NULL;
}

static void
ttm_pool_unpopulate_helper(struct ttm_tt *ttm, unsigned mem_count_update)
{
	struct ttm_mem_global *mem_glob = ttm->bdev->glob->mem_glob;
	unsigned i;

	if (mem_count_update == 0)
		goto put_pages;

	for (i = 0; i < mem_count_update; ++i) {
		if (!ttm->pages[i])
			continue;

		ttm_mem_global_free_page(mem_glob, ttm->pages[i], PAGE_SIZE);
	}

put_pages:
	ttm_put_pages(ttm->pages, ttm->num_pages, ttm->page_flags,
		      ttm->caching_state);
	ttm->state = tt_unpopulated;
}

int ttm_pool_populate(struct ttm_tt *ttm, struct ttm_operation_ctx *ctx)
{
	struct ttm_mem_global *mem_glob = ttm->bdev->glob->mem_glob;
	unsigned i;
	int ret;

	if (ttm->state != tt_unpopulated)
		return 0;

	ret = ttm_get_pages(ttm->pages, ttm->num_pages, ttm->page_flags,
			    ttm->caching_state);
	if (unlikely(ret != 0)) {
		ttm_pool_unpopulate_helper(ttm, 0);
		return ret;
	}

	for (i = 0; i < ttm->num_pages; ++i) {
		ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
						PAGE_SIZE, ctx);
		if (unlikely(ret != 0)) {
			ttm_pool_unpopulate_helper(ttm, i);
			return -ENOMEM;
		}
	}

	if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
		ret = ttm_tt_swapin(ttm);
		if (unlikely(ret != 0)) {
			ttm_pool_unpopulate(ttm);
			return ret;
		}
	}

	ttm->state = tt_unbound;
	return 0;
}
EXPORT_SYMBOL(ttm_pool_populate);

void ttm_pool_unpopulate(struct ttm_tt *ttm)
{
	ttm_pool_unpopulate_helper(ttm, ttm->num_pages);
}
EXPORT_SYMBOL(ttm_pool_unpopulate);

int ttm_populate_and_map_pages(struct device *dev, struct ttm_dma_tt *tt,
					struct ttm_operation_ctx *ctx)
{
	unsigned i, j;
	int r;

	r = ttm_pool_populate(&tt->ttm, ctx);
	if (r)
		return r;

	for (i = 0; i < tt->ttm.num_pages; ++i) {
		struct page *p = tt->ttm.pages[i];
		size_t num_pages = 1;

		for (j = i + 1; j < tt->ttm.num_pages; ++j) {
			if (++p != tt->ttm.pages[j])
				break;

			++num_pages;
		}

		tt->dma_address[i] = dma_map_page(dev, tt->ttm.pages[i],
						  0, num_pages * PAGE_SIZE,
						  DMA_BIDIRECTIONAL);
		if (dma_mapping_error(dev, tt->dma_address[i])) {
			while (i--) {
				dma_unmap_page(dev, tt->dma_address[i],
					       PAGE_SIZE, DMA_BIDIRECTIONAL);
				tt->dma_address[i] = 0;
			}
			ttm_pool_unpopulate(&tt->ttm);
			return -EFAULT;
		}

		for (j = 1; j < num_pages; ++j) {
			tt->dma_address[i + 1] = tt->dma_address[i] + PAGE_SIZE;
			++i;
		}
	}
	return 0;
}
EXPORT_SYMBOL(ttm_populate_and_map_pages);

void ttm_unmap_and_unpopulate_pages(struct device *dev, struct ttm_dma_tt *tt)
{
	unsigned i, j;

	for (i = 0; i < tt->ttm.num_pages;) {
		struct page *p = tt->ttm.pages[i];
		size_t num_pages = 1;

		if (!tt->dma_address[i] || !tt->ttm.pages[i]) {
			++i;
			continue;
		}

		for (j = i + 1; j < tt->ttm.num_pages; ++j) {
			if (++p != tt->ttm.pages[j])
				break;

			++num_pages;
		}

		dma_unmap_page(dev, tt->dma_address[i], num_pages * PAGE_SIZE,
			       DMA_BIDIRECTIONAL);

		i += num_pages;
	}
	ttm_pool_unpopulate(&tt->ttm);
}
EXPORT_SYMBOL(ttm_unmap_and_unpopulate_pages);

int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
{
	struct ttm_page_pool *p;
	unsigned i;
	char *h[] = {"pool", "refills", "pages freed", "size"};
	if (!_manager) {
		seq_printf(m, "No pool allocator running.\n");
		return 0;
	}
	seq_printf(m, "%7s %12s %13s %8s\n",
			h[0], h[1], h[2], h[3]);
	for (i = 0; i < NUM_POOLS; ++i) {
		p = &_manager->pools[i];

		seq_printf(m, "%7s %12ld %13ld %8d\n",
				p->name, p->nrefills,
				p->nfrees, p->npages);
	}
	return 0;
}
EXPORT_SYMBOL(ttm_page_alloc_debugfs);