summaryrefslogtreecommitdiffstats
path: root/src/intel/vulkan/anv_allocator.c
blob: f884ac3b8270f5e051827a6ea9fd077770629ccf (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
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
/*
 * Copyright © 2015 Intel Corporation
 *
 * 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, sublicense,
 * 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 NONINFRINGEMENT.  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.
 */

#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <assert.h>
#include <linux/memfd.h>
#include <sys/mman.h>

#include "anv_private.h"

#include "util/hash_table.h"
#include "util/simple_mtx.h"

#ifdef HAVE_VALGRIND
#define VG_NOACCESS_READ(__ptr) ({                       \
   VALGRIND_MAKE_MEM_DEFINED((__ptr), sizeof(*(__ptr))); \
   __typeof(*(__ptr)) __val = *(__ptr);                  \
   VALGRIND_MAKE_MEM_NOACCESS((__ptr), sizeof(*(__ptr)));\
   __val;                                                \
})
#define VG_NOACCESS_WRITE(__ptr, __val) ({                  \
   VALGRIND_MAKE_MEM_UNDEFINED((__ptr), sizeof(*(__ptr)));  \
   *(__ptr) = (__val);                                      \
   VALGRIND_MAKE_MEM_NOACCESS((__ptr), sizeof(*(__ptr)));   \
})
#else
#define VG_NOACCESS_READ(__ptr) (*(__ptr))
#define VG_NOACCESS_WRITE(__ptr, __val) (*(__ptr) = (__val))
#endif

/* Design goals:
 *
 *  - Lock free (except when resizing underlying bos)
 *
 *  - Constant time allocation with typically only one atomic
 *
 *  - Multiple allocation sizes without fragmentation
 *
 *  - Can grow while keeping addresses and offset of contents stable
 *
 *  - All allocations within one bo so we can point one of the
 *    STATE_BASE_ADDRESS pointers at it.
 *
 * The overall design is a two-level allocator: top level is a fixed size, big
 * block (8k) allocator, which operates out of a bo.  Allocation is done by
 * either pulling a block from the free list or growing the used range of the
 * bo.  Growing the range may run out of space in the bo which we then need to
 * grow.  Growing the bo is tricky in a multi-threaded, lockless environment:
 * we need to keep all pointers and contents in the old map valid.  GEM bos in
 * general can't grow, but we use a trick: we create a memfd and use ftruncate
 * to grow it as necessary.  We mmap the new size and then create a gem bo for
 * it using the new gem userptr ioctl.  Without heavy-handed locking around
 * our allocation fast-path, there isn't really a way to munmap the old mmap,
 * so we just keep it around until garbage collection time.  While the block
 * allocator is lockless for normal operations, we block other threads trying
 * to allocate while we're growing the map.  It sholdn't happen often, and
 * growing is fast anyway.
 *
 * At the next level we can use various sub-allocators.  The state pool is a
 * pool of smaller, fixed size objects, which operates much like the block
 * pool.  It uses a free list for freeing objects, but when it runs out of
 * space it just allocates a new block from the block pool.  This allocator is
 * intended for longer lived state objects such as SURFACE_STATE and most
 * other persistent state objects in the API.  We may need to track more info
 * with these object and a pointer back to the CPU object (eg VkImage).  In
 * those cases we just allocate a slightly bigger object and put the extra
 * state after the GPU state object.
 *
 * The state stream allocator works similar to how the i965 DRI driver streams
 * all its state.  Even with Vulkan, we need to emit transient state (whether
 * surface state base or dynamic state base), and for that we can just get a
 * block and fill it up.  These cases are local to a command buffer and the
 * sub-allocator need not be thread safe.  The streaming allocator gets a new
 * block when it runs out of space and chains them together so they can be
 * easily freed.
 */

/* Allocations are always at least 64 byte aligned, so 1 is an invalid value.
 * We use it to indicate the free list is empty. */
#define EMPTY 1

struct anv_mmap_cleanup {
   void *map;
   size_t size;
   uint32_t gem_handle;
};

#define ANV_MMAP_CLEANUP_INIT ((struct anv_mmap_cleanup){0})

#ifndef HAVE_MEMFD_CREATE
static inline int
memfd_create(const char *name, unsigned int flags)
{
   return syscall(SYS_memfd_create, name, flags);
}
#endif

static inline uint32_t
ilog2_round_up(uint32_t value)
{
   assert(value != 0);
   return 32 - __builtin_clz(value - 1);
}

static inline uint32_t
round_to_power_of_two(uint32_t value)
{
   return 1 << ilog2_round_up(value);
}

static bool
anv_free_list_pop(union anv_free_list *list, void **map, int32_t *offset)
{
   union anv_free_list current, new, old;

   current.u64 = list->u64;
   while (current.offset != EMPTY) {
      /* We have to add a memory barrier here so that the list head (and
       * offset) gets read before we read the map pointer.  This way we
       * know that the map pointer is valid for the given offset at the
       * point where we read it.
       */
      __sync_synchronize();

      int32_t *next_ptr = *map + current.offset;
      new.offset = VG_NOACCESS_READ(next_ptr);
      new.count = current.count + 1;
      old.u64 = __sync_val_compare_and_swap(&list->u64, current.u64, new.u64);
      if (old.u64 == current.u64) {
         *offset = current.offset;
         return true;
      }
      current = old;
   }

   return false;
}

static void
anv_free_list_push(union anv_free_list *list, void *map, int32_t offset,
                   uint32_t size, uint32_t count)
{
   union anv_free_list current, old, new;
   int32_t *next_ptr = map + offset;

   /* If we're returning more than one chunk, we need to build a chain to add
    * to the list.  Fortunately, we can do this without any atomics since we
    * own everything in the chain right now.  `offset` is left pointing to the
    * head of our chain list while `next_ptr` points to the tail.
    */
   for (uint32_t i = 1; i < count; i++) {
      VG_NOACCESS_WRITE(next_ptr, offset + i * size);
      next_ptr = map + offset + i * size;
   }

   old = *list;
   do {
      current = old;
      VG_NOACCESS_WRITE(next_ptr, current.offset);
      new.offset = offset;
      new.count = current.count + 1;
      old.u64 = __sync_val_compare_and_swap(&list->u64, current.u64, new.u64);
   } while (old.u64 != current.u64);
}

/* All pointers in the ptr_free_list are assumed to be page-aligned.  This
 * means that the bottom 12 bits should all be zero.
 */
#define PFL_COUNT(x) ((uintptr_t)(x) & 0xfff)
#define PFL_PTR(x) ((void *)((uintptr_t)(x) & ~(uintptr_t)0xfff))
#define PFL_PACK(ptr, count) ({           \
   (void *)(((uintptr_t)(ptr) & ~(uintptr_t)0xfff) | ((count) & 0xfff)); \
})

static bool
anv_ptr_free_list_pop(void **list, void **elem)
{
   void *current = *list;
   while (PFL_PTR(current) != NULL) {
      void **next_ptr = PFL_PTR(current);
      void *new_ptr = VG_NOACCESS_READ(next_ptr);
      unsigned new_count = PFL_COUNT(current) + 1;
      void *new = PFL_PACK(new_ptr, new_count);
      void *old = __sync_val_compare_and_swap(list, current, new);
      if (old == current) {
         *elem = PFL_PTR(current);
         return true;
      }
      current = old;
   }

   return false;
}

static void
anv_ptr_free_list_push(void **list, void *elem)
{
   void *old, *current;
   void **next_ptr = elem;

   /* The pointer-based free list requires that the pointer be
    * page-aligned.  This is because we use the bottom 12 bits of the
    * pointer to store a counter to solve the ABA concurrency problem.
    */
   assert(((uintptr_t)elem & 0xfff) == 0);

   old = *list;
   do {
      current = old;
      VG_NOACCESS_WRITE(next_ptr, PFL_PTR(current));
      unsigned new_count = PFL_COUNT(current) + 1;
      void *new = PFL_PACK(elem, new_count);
      old = __sync_val_compare_and_swap(list, current, new);
   } while (old != current);
}

static VkResult
anv_block_pool_expand_range(struct anv_block_pool *pool,
                            uint32_t center_bo_offset, uint32_t size);

VkResult
anv_block_pool_init(struct anv_block_pool *pool,
                    struct anv_device *device,
                    uint32_t initial_size,
                    uint64_t bo_flags)
{
   VkResult result;

   pool->device = device;
   pool->bo_flags = bo_flags;
   anv_bo_init(&pool->bo, 0, 0);

   pool->fd = memfd_create("block pool", MFD_CLOEXEC);
   if (pool->fd == -1)
      return vk_error(VK_ERROR_INITIALIZATION_FAILED);

   /* Just make it 2GB up-front.  The Linux kernel won't actually back it
    * with pages until we either map and fault on one of them or we use
    * userptr and send a chunk of it off to the GPU.
    */
   if (ftruncate(pool->fd, BLOCK_POOL_MEMFD_SIZE) == -1) {
      result = vk_error(VK_ERROR_INITIALIZATION_FAILED);
      goto fail_fd;
   }

   if (!u_vector_init(&pool->mmap_cleanups,
                      round_to_power_of_two(sizeof(struct anv_mmap_cleanup)),
                      128)) {
      result = vk_error(VK_ERROR_INITIALIZATION_FAILED);
      goto fail_fd;
   }

   pool->state.next = 0;
   pool->state.end = 0;
   pool->back_state.next = 0;
   pool->back_state.end = 0;

   result = anv_block_pool_expand_range(pool, 0, initial_size);
   if (result != VK_SUCCESS)
      goto fail_mmap_cleanups;

   return VK_SUCCESS;

 fail_mmap_cleanups:
   u_vector_finish(&pool->mmap_cleanups);
 fail_fd:
   close(pool->fd);

   return result;
}

void
anv_block_pool_finish(struct anv_block_pool *pool)
{
   struct anv_mmap_cleanup *cleanup;

   u_vector_foreach(cleanup, &pool->mmap_cleanups) {
      if (cleanup->map)
         munmap(cleanup->map, cleanup->size);
      if (cleanup->gem_handle)
         anv_gem_close(pool->device, cleanup->gem_handle);
   }

   u_vector_finish(&pool->mmap_cleanups);

   close(pool->fd);
}

#define PAGE_SIZE 4096

static VkResult
anv_block_pool_expand_range(struct anv_block_pool *pool,
                            uint32_t center_bo_offset, uint32_t size)
{
   void *map;
   uint32_t gem_handle;
   struct anv_mmap_cleanup *cleanup;

   /* Assert that we only ever grow the pool */
   assert(center_bo_offset >= pool->back_state.end);
   assert(size - center_bo_offset >= pool->state.end);

   /* Assert that we don't go outside the bounds of the memfd */
   assert(center_bo_offset <= BLOCK_POOL_MEMFD_CENTER);
   assert(size - center_bo_offset <=
          BLOCK_POOL_MEMFD_SIZE - BLOCK_POOL_MEMFD_CENTER);

   cleanup = u_vector_add(&pool->mmap_cleanups);
   if (!cleanup)
      return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);

   *cleanup = ANV_MMAP_CLEANUP_INIT;

   /* Just leak the old map until we destroy the pool.  We can't munmap it
    * without races or imposing locking on the block allocate fast path. On
    * the whole the leaked maps adds up to less than the size of the
    * current map.  MAP_POPULATE seems like the right thing to do, but we
    * should try to get some numbers.
    */
   map = mmap(NULL, size, PROT_READ | PROT_WRITE,
              MAP_SHARED | MAP_POPULATE, pool->fd,
              BLOCK_POOL_MEMFD_CENTER - center_bo_offset);
   if (map == MAP_FAILED)
      return vk_errorf(pool->device->instance, pool->device,
                       VK_ERROR_MEMORY_MAP_FAILED, "mmap failed: %m");

   gem_handle = anv_gem_userptr(pool->device, map, size);
   if (gem_handle == 0) {
      munmap(map, size);
      return vk_errorf(pool->device->instance, pool->device,
                       VK_ERROR_TOO_MANY_OBJECTS, "userptr failed: %m");
   }

   cleanup->map = map;
   cleanup->size = size;
   cleanup->gem_handle = gem_handle;

#if 0
   /* Regular objects are created I915_CACHING_CACHED on LLC platforms and
    * I915_CACHING_NONE on non-LLC platforms. However, userptr objects are
    * always created as I915_CACHING_CACHED, which on non-LLC means
    * snooped. That can be useful but comes with a bit of overheard.  Since
    * we're eplicitly clflushing and don't want the overhead we need to turn
    * it off. */
   if (!pool->device->info.has_llc) {
      anv_gem_set_caching(pool->device, gem_handle, I915_CACHING_NONE);
      anv_gem_set_domain(pool->device, gem_handle,
                         I915_GEM_DOMAIN_GTT, I915_GEM_DOMAIN_GTT);
   }
#endif

   /* Now that we successfull allocated everything, we can write the new
    * values back into pool. */
   pool->map = map + center_bo_offset;
   pool->center_bo_offset = center_bo_offset;

   /* For block pool BOs we have to be a bit careful about where we place them
    * in the GTT.  There are two documented workarounds for state base address
    * placement : Wa32bitGeneralStateOffset and Wa32bitInstructionBaseOffset
    * which state that those two base addresses do not support 48-bit
    * addresses and need to be placed in the bottom 32-bit range.
    * Unfortunately, this is not quite accurate.
    *
    * The real problem is that we always set the size of our state pools in
    * STATE_BASE_ADDRESS to 0xfffff (the maximum) even though the BO is most
    * likely significantly smaller.  We do this because we do not no at the
    * time we emit STATE_BASE_ADDRESS whether or not we will need to expand
    * the pool during command buffer building so we don't actually have a
    * valid final size.  If the address + size, as seen by STATE_BASE_ADDRESS
    * overflows 48 bits, the GPU appears to treat all accesses to the buffer
    * as being out of bounds and returns zero.  For dynamic state, this
    * usually just leads to rendering corruptions, but shaders that are all
    * zero hang the GPU immediately.
    *
    * The easiest solution to do is exactly what the bogus workarounds say to
    * do: restrict these buffers to 32-bit addresses.  We could also pin the
    * BO to some particular location of our choosing, but that's significantly
    * more work than just not setting a flag.  So, we explicitly DO NOT set
    * the EXEC_OBJECT_SUPPORTS_48B_ADDRESS flag and the kernel does all of the
    * hard work for us.
    */
   anv_bo_init(&pool->bo, gem_handle, size);
   pool->bo.flags = pool->bo_flags;
   pool->bo.map = map;

   return VK_SUCCESS;
}

/** Grows and re-centers the block pool.
 *
 * We grow the block pool in one or both directions in such a way that the
 * following conditions are met:
 *
 *  1) The size of the entire pool is always a power of two.
 *
 *  2) The pool only grows on both ends.  Neither end can get
 *     shortened.
 *
 *  3) At the end of the allocation, we have about twice as much space
 *     allocated for each end as we have used.  This way the pool doesn't
 *     grow too far in one direction or the other.
 *
 *  4) If the _alloc_back() has never been called, then the back portion of
 *     the pool retains a size of zero.  (This makes it easier for users of
 *     the block pool that only want a one-sided pool.)
 *
 *  5) We have enough space allocated for at least one more block in
 *     whichever side `state` points to.
 *
 *  6) The center of the pool is always aligned to both the block_size of
 *     the pool and a 4K CPU page.
 */
static uint32_t
anv_block_pool_grow(struct anv_block_pool *pool, struct anv_block_state *state)
{
   VkResult result = VK_SUCCESS;

   pthread_mutex_lock(&pool->device->mutex);

   assert(state == &pool->state || state == &pool->back_state);

   /* Gather a little usage information on the pool.  Since we may have
    * threadsd waiting in queue to get some storage while we resize, it's
    * actually possible that total_used will be larger than old_size.  In
    * particular, block_pool_alloc() increments state->next prior to
    * calling block_pool_grow, so this ensures that we get enough space for
    * which ever side tries to grow the pool.
    *
    * We align to a page size because it makes it easier to do our
    * calculations later in such a way that we state page-aigned.
    */
   uint32_t back_used = align_u32(pool->back_state.next, PAGE_SIZE);
   uint32_t front_used = align_u32(pool->state.next, PAGE_SIZE);
   uint32_t total_used = front_used + back_used;

   assert(state == &pool->state || back_used > 0);

   uint32_t old_size = pool->bo.size;

   /* The block pool is always initialized to a nonzero size and this function
    * is always called after initialization.
    */
   assert(old_size > 0);

   /* The back_used and front_used may actually be smaller than the actual
    * requirement because they are based on the next pointers which are
    * updated prior to calling this function.
    */
   uint32_t back_required = MAX2(back_used, pool->center_bo_offset);
   uint32_t front_required = MAX2(front_used, old_size - pool->center_bo_offset);

   if (back_used * 2 <= back_required && front_used * 2 <= front_required) {
      /* If we're in this case then this isn't the firsta allocation and we
       * already have enough space on both sides to hold double what we
       * have allocated.  There's nothing for us to do.
       */
      goto done;
   }

   uint32_t size = old_size * 2;
   while (size < back_required + front_required)
      size *= 2;

   assert(size > pool->bo.size);

   /* We compute a new center_bo_offset such that, when we double the size
    * of the pool, we maintain the ratio of how much is used by each side.
    * This way things should remain more-or-less balanced.
    */
   uint32_t center_bo_offset;
   if (back_used == 0) {
      /* If we're in this case then we have never called alloc_back().  In
       * this case, we want keep the offset at 0 to make things as simple
       * as possible for users that don't care about back allocations.
       */
      center_bo_offset = 0;
   } else {
      /* Try to "center" the allocation based on how much is currently in
       * use on each side of the center line.
       */
      center_bo_offset = ((uint64_t)size * back_used) / total_used;

      /* Align down to a multiple of the page size */
      center_bo_offset &= ~(PAGE_SIZE - 1);

      assert(center_bo_offset >= back_used);

      /* Make sure we don't shrink the back end of the pool */
      if (center_bo_offset < pool->back_state.end)
         center_bo_offset = pool->back_state.end;

      /* Make sure that we don't shrink the front end of the pool */
      if (size - center_bo_offset < pool->state.end)
         center_bo_offset = size - pool->state.end;
   }

   assert(center_bo_offset % PAGE_SIZE == 0);

   result = anv_block_pool_expand_range(pool, center_bo_offset, size);

   pool->bo.flags = pool->bo_flags;

done:
   pthread_mutex_unlock(&pool->device->mutex);

   if (result == VK_SUCCESS) {
      /* Return the appropriate new size.  This function never actually
       * updates state->next.  Instead, we let the caller do that because it
       * needs to do so in order to maintain its concurrency model.
       */
      if (state == &pool->state) {
         return pool->bo.size - pool->center_bo_offset;
      } else {
         assert(pool->center_bo_offset > 0);
         return pool->center_bo_offset;
      }
   } else {
      return 0;
   }
}

static uint32_t
anv_block_pool_alloc_new(struct anv_block_pool *pool,
                         struct anv_block_state *pool_state,
                         uint32_t block_size)
{
   struct anv_block_state state, old, new;

   while (1) {
      state.u64 = __sync_fetch_and_add(&pool_state->u64, block_size);
      if (state.next + block_size <= state.end) {
         assert(pool->map);
         return state.next;
      } else if (state.next <= state.end) {
         /* We allocated the first block outside the pool so we have to grow
          * the pool.  pool_state->next acts a mutex: threads who try to
          * allocate now will get block indexes above the current limit and
          * hit futex_wait below.
          */
         new.next = state.next + block_size;
         do {
            new.end = anv_block_pool_grow(pool, pool_state);
         } while (new.end < new.next);

         old.u64 = __sync_lock_test_and_set(&pool_state->u64, new.u64);
         if (old.next != state.next)
            futex_wake(&pool_state->end, INT_MAX);
         return state.next;
      } else {
         futex_wait(&pool_state->end, state.end, NULL);
         continue;
      }
   }
}

int32_t
anv_block_pool_alloc(struct anv_block_pool *pool,
                     uint32_t block_size)
{
   return anv_block_pool_alloc_new(pool, &pool->state, block_size);
}

/* Allocates a block out of the back of the block pool.
 *
 * This will allocated a block earlier than the "start" of the block pool.
 * The offsets returned from this function will be negative but will still
 * be correct relative to the block pool's map pointer.
 *
 * If you ever use anv_block_pool_alloc_back, then you will have to do
 * gymnastics with the block pool's BO when doing relocations.
 */
int32_t
anv_block_pool_alloc_back(struct anv_block_pool *pool,
                          uint32_t block_size)
{
   int32_t offset = anv_block_pool_alloc_new(pool, &pool->back_state,
                                             block_size);

   /* The offset we get out of anv_block_pool_alloc_new() is actually the
    * number of bytes downwards from the middle to the end of the block.
    * We need to turn it into a (negative) offset from the middle to the
    * start of the block.
    */
   assert(offset >= 0);
   return -(offset + block_size);
}

VkResult
anv_state_pool_init(struct anv_state_pool *pool,
                    struct anv_device *device,
                    uint32_t block_size,
                    uint64_t bo_flags)
{
   VkResult result = anv_block_pool_init(&pool->block_pool, device,
                                         block_size * 16,
                                         bo_flags);
   if (result != VK_SUCCESS)
      return result;

   assert(util_is_power_of_two_or_zero(block_size));
   pool->block_size = block_size;
   pool->back_alloc_free_list = ANV_FREE_LIST_EMPTY;
   for (unsigned i = 0; i < ANV_STATE_BUCKETS; i++) {
      pool->buckets[i].free_list = ANV_FREE_LIST_EMPTY;
      pool->buckets[i].block.next = 0;
      pool->buckets[i].block.end = 0;
   }
   VG(VALGRIND_CREATE_MEMPOOL(pool, 0, false));

   return VK_SUCCESS;
}

void
anv_state_pool_finish(struct anv_state_pool *pool)
{
   VG(VALGRIND_DESTROY_MEMPOOL(pool));
   anv_block_pool_finish(&pool->block_pool);
}

static uint32_t
anv_fixed_size_state_pool_alloc_new(struct anv_fixed_size_state_pool *pool,
                                    struct anv_block_pool *block_pool,
                                    uint32_t state_size,
                                    uint32_t block_size)
{
   struct anv_block_state block, old, new;
   uint32_t offset;

   /* If our state is large, we don't need any sub-allocation from a block.
    * Instead, we just grab whole (potentially large) blocks.
    */
   if (state_size >= block_size)
      return anv_block_pool_alloc(block_pool, state_size);

 restart:
   block.u64 = __sync_fetch_and_add(&pool->block.u64, state_size);

   if (block.next < block.end) {
      return block.next;
   } else if (block.next == block.end) {
      offset = anv_block_pool_alloc(block_pool, block_size);
      new.next = offset + state_size;
      new.end = offset + block_size;
      old.u64 = __sync_lock_test_and_set(&pool->block.u64, new.u64);
      if (old.next != block.next)
         futex_wake(&pool->block.end, INT_MAX);
      return offset;
   } else {
      futex_wait(&pool->block.end, block.end, NULL);
      goto restart;
   }
}

static uint32_t
anv_state_pool_get_bucket(uint32_t size)
{
   unsigned size_log2 = ilog2_round_up(size);
   assert(size_log2 <= ANV_MAX_STATE_SIZE_LOG2);
   if (size_log2 < ANV_MIN_STATE_SIZE_LOG2)
      size_log2 = ANV_MIN_STATE_SIZE_LOG2;
   return size_log2 - ANV_MIN_STATE_SIZE_LOG2;
}

static uint32_t
anv_state_pool_get_bucket_size(uint32_t bucket)
{
   uint32_t size_log2 = bucket + ANV_MIN_STATE_SIZE_LOG2;
   return 1 << size_log2;
}

static struct anv_state
anv_state_pool_alloc_no_vg(struct anv_state_pool *pool,
                           uint32_t size, uint32_t align)
{
   uint32_t bucket = anv_state_pool_get_bucket(MAX2(size, align));

   struct anv_state state;
   state.alloc_size = anv_state_pool_get_bucket_size(bucket);

   /* Try free list first. */
   if (anv_free_list_pop(&pool->buckets[bucket].free_list,
                         &pool->block_pool.map, &state.offset)) {
      assert(state.offset >= 0);
      goto done;
   }

   /* Try to grab a chunk from some larger bucket and split it up */
   for (unsigned b = bucket + 1; b < ANV_STATE_BUCKETS; b++) {
      int32_t chunk_offset;
      if (anv_free_list_pop(&pool->buckets[b].free_list,
                            &pool->block_pool.map, &chunk_offset)) {
         unsigned chunk_size = anv_state_pool_get_bucket_size(b);

         /* We've found a chunk that's larger than the requested state size.
          * There are a couple of options as to what we do with it:
          *
          *    1) We could fully split the chunk into state.alloc_size sized
          *       pieces.  However, this would mean that allocating a 16B
          *       state could potentially split a 2MB chunk into 512K smaller
          *       chunks.  This would lead to unnecessary fragmentation.
          *
          *    2) The classic "buddy allocator" method would have us split the
          *       chunk in half and return one half.  Then we would split the
          *       remaining half in half and return one half, and repeat as
          *       needed until we get down to the size we want.  However, if
          *       you are allocating a bunch of the same size state (which is
          *       the common case), this means that every other allocation has
          *       to go up a level and every fourth goes up two levels, etc.
          *       This is not nearly as efficient as it could be if we did a
          *       little more work up-front.
          *
          *    3) Split the difference between (1) and (2) by doing a
          *       two-level split.  If it's bigger than some fixed block_size,
          *       we split it into block_size sized chunks and return all but
          *       one of them.  Then we split what remains into
          *       state.alloc_size sized chunks and return all but one.
          *
          * We choose option (3).
          */
         if (chunk_size > pool->block_size &&
             state.alloc_size < pool->block_size) {
            assert(chunk_size % pool->block_size == 0);
            /* We don't want to split giant chunks into tiny chunks.  Instead,
             * break anything bigger than a block into block-sized chunks and
             * then break it down into bucket-sized chunks from there.  Return
             * all but the first block of the chunk to the block bucket.
             */
            const uint32_t block_bucket =
               anv_state_pool_get_bucket(pool->block_size);
            anv_free_list_push(&pool->buckets[block_bucket].free_list,
                               pool->block_pool.map,
                               chunk_offset + pool->block_size,
                               pool->block_size,
                               (chunk_size / pool->block_size) - 1);
            chunk_size = pool->block_size;
         }

         assert(chunk_size % state.alloc_size == 0);
         anv_free_list_push(&pool->buckets[bucket].free_list,
                            pool->block_pool.map,
                            chunk_offset + state.alloc_size,
                            state.alloc_size,
                            (chunk_size / state.alloc_size) - 1);

         state.offset = chunk_offset;
         goto done;
      }
   }

   state.offset = anv_fixed_size_state_pool_alloc_new(&pool->buckets[bucket],
                                                      &pool->block_pool,
                                                      state.alloc_size,
                                                      pool->block_size);

done:
   state.map = pool->block_pool.map + state.offset;
   return state;
}

struct anv_state
anv_state_pool_alloc(struct anv_state_pool *pool, uint32_t size, uint32_t align)
{
   if (size == 0)
      return ANV_STATE_NULL;

   struct anv_state state = anv_state_pool_alloc_no_vg(pool, size, align);
   VG(VALGRIND_MEMPOOL_ALLOC(pool, state.map, size));
   return state;
}

struct anv_state
anv_state_pool_alloc_back(struct anv_state_pool *pool)
{
   struct anv_state state;
   state.alloc_size = pool->block_size;

   if (anv_free_list_pop(&pool->back_alloc_free_list,
                         &pool->block_pool.map, &state.offset)) {
      assert(state.offset < 0);
      goto done;
   }

   state.offset = anv_block_pool_alloc_back(&pool->block_pool,
                                            pool->block_size);

done:
   state.map = pool->block_pool.map + state.offset;
   VG(VALGRIND_MEMPOOL_ALLOC(pool, state.map, state.alloc_size));
   return state;
}

static void
anv_state_pool_free_no_vg(struct anv_state_pool *pool, struct anv_state state)
{
   assert(util_is_power_of_two_or_zero(state.alloc_size));
   unsigned bucket = anv_state_pool_get_bucket(state.alloc_size);

   if (state.offset < 0) {
      assert(state.alloc_size == pool->block_size);
      anv_free_list_push(&pool->back_alloc_free_list,
                         pool->block_pool.map, state.offset,
                         state.alloc_size, 1);
   } else {
      anv_free_list_push(&pool->buckets[bucket].free_list,
                         pool->block_pool.map, state.offset,
                         state.alloc_size, 1);
   }
}

void
anv_state_pool_free(struct anv_state_pool *pool, struct anv_state state)
{
   if (state.alloc_size == 0)
      return;

   VG(VALGRIND_MEMPOOL_FREE(pool, state.map));
   anv_state_pool_free_no_vg(pool, state);
}

struct anv_state_stream_block {
   struct anv_state block;

   /* The next block */
   struct anv_state_stream_block *next;

#ifdef HAVE_VALGRIND
   /* A pointer to the first user-allocated thing in this block.  This is
    * what valgrind sees as the start of the block.
    */
   void *_vg_ptr;
#endif
};

/* The state stream allocator is a one-shot, single threaded allocator for
 * variable sized blocks.  We use it for allocating dynamic state.
 */
void
anv_state_stream_init(struct anv_state_stream *stream,
                      struct anv_state_pool *state_pool,
                      uint32_t block_size)
{
   stream->state_pool = state_pool;
   stream->block_size = block_size;

   stream->block = ANV_STATE_NULL;

   stream->block_list = NULL;

   /* Ensure that next + whatever > block_size.  This way the first call to
    * state_stream_alloc fetches a new block.
    */
   stream->next = block_size;

   VG(VALGRIND_CREATE_MEMPOOL(stream, 0, false));
}

void
anv_state_stream_finish(struct anv_state_stream *stream)
{
   struct anv_state_stream_block *next = stream->block_list;
   while (next != NULL) {
      struct anv_state_stream_block sb = VG_NOACCESS_READ(next);
      VG(VALGRIND_MEMPOOL_FREE(stream, sb._vg_ptr));
      VG(VALGRIND_MAKE_MEM_UNDEFINED(next, stream->block_size));
      anv_state_pool_free_no_vg(stream->state_pool, sb.block);
      next = sb.next;
   }

   VG(VALGRIND_DESTROY_MEMPOOL(stream));
}

struct anv_state
anv_state_stream_alloc(struct anv_state_stream *stream,
                       uint32_t size, uint32_t alignment)
{
   if (size == 0)
      return ANV_STATE_NULL;

   assert(alignment <= PAGE_SIZE);

   uint32_t offset = align_u32(stream->next, alignment);
   if (offset + size > stream->block.alloc_size) {
      uint32_t block_size = stream->block_size;
      if (block_size < size)
         block_size = round_to_power_of_two(size);

      stream->block = anv_state_pool_alloc_no_vg(stream->state_pool,
                                                 block_size, PAGE_SIZE);

      struct anv_state_stream_block *sb = stream->block.map;
      VG_NOACCESS_WRITE(&sb->block, stream->block);
      VG_NOACCESS_WRITE(&sb->next, stream->block_list);
      stream->block_list = sb;
      VG(VG_NOACCESS_WRITE(&sb->_vg_ptr, NULL));

      VG(VALGRIND_MAKE_MEM_NOACCESS(stream->block.map, stream->block_size));

      /* Reset back to the start plus space for the header */
      stream->next = sizeof(*sb);

      offset = align_u32(stream->next, alignment);
      assert(offset + size <= stream->block.alloc_size);
   }

   struct anv_state state = stream->block;
   state.offset += offset;
   state.alloc_size = size;
   state.map += offset;

   stream->next = offset + size;

#ifdef HAVE_VALGRIND
   struct anv_state_stream_block *sb = stream->block_list;
   void *vg_ptr = VG_NOACCESS_READ(&sb->_vg_ptr);
   if (vg_ptr == NULL) {
      vg_ptr = state.map;
      VG_NOACCESS_WRITE(&sb->_vg_ptr, vg_ptr);
      VALGRIND_MEMPOOL_ALLOC(stream, vg_ptr, size);
   } else {
      void *state_end = state.map + state.alloc_size;
      /* This only updates the mempool.  The newly allocated chunk is still
       * marked as NOACCESS. */
      VALGRIND_MEMPOOL_CHANGE(stream, vg_ptr, vg_ptr, state_end - vg_ptr);
      /* Mark the newly allocated chunk as undefined */
      VALGRIND_MAKE_MEM_UNDEFINED(state.map, state.alloc_size);
   }
#endif

   return state;
}

struct bo_pool_bo_link {
   struct bo_pool_bo_link *next;
   struct anv_bo bo;
};

void
anv_bo_pool_init(struct anv_bo_pool *pool, struct anv_device *device,
                 uint64_t bo_flags)
{
   pool->device = device;
   pool->bo_flags = bo_flags;
   memset(pool->free_list, 0, sizeof(pool->free_list));

   VG(VALGRIND_CREATE_MEMPOOL(pool, 0, false));
}

void
anv_bo_pool_finish(struct anv_bo_pool *pool)
{
   for (unsigned i = 0; i < ARRAY_SIZE(pool->free_list); i++) {
      struct bo_pool_bo_link *link = PFL_PTR(pool->free_list[i]);
      while (link != NULL) {
         struct bo_pool_bo_link link_copy = VG_NOACCESS_READ(link);

         anv_gem_munmap(link_copy.bo.map, link_copy.bo.size);
         anv_gem_close(pool->device, link_copy.bo.gem_handle);
         link = link_copy.next;
      }
   }

   VG(VALGRIND_DESTROY_MEMPOOL(pool));
}

VkResult
anv_bo_pool_alloc(struct anv_bo_pool *pool, struct anv_bo *bo, uint32_t size)
{
   VkResult result;

   const unsigned size_log2 = size < 4096 ? 12 : ilog2_round_up(size);
   const unsigned pow2_size = 1 << size_log2;
   const unsigned bucket = size_log2 - 12;
   assert(bucket < ARRAY_SIZE(pool->free_list));

   void *next_free_void;
   if (anv_ptr_free_list_pop(&pool->free_list[bucket], &next_free_void)) {
      struct bo_pool_bo_link *next_free = next_free_void;
      *bo = VG_NOACCESS_READ(&next_free->bo);
      assert(bo->gem_handle);
      assert(bo->map == next_free);
      assert(size <= bo->size);

      VG(VALGRIND_MEMPOOL_ALLOC(pool, bo->map, size));

      return VK_SUCCESS;
   }

   struct anv_bo new_bo;

   result = anv_bo_init_new(&new_bo, pool->device, pow2_size);
   if (result != VK_SUCCESS)
      return result;

   new_bo.flags = pool->bo_flags;

   assert(new_bo.size == pow2_size);

   new_bo.map = anv_gem_mmap(pool->device, new_bo.gem_handle, 0, pow2_size, 0);
   if (new_bo.map == MAP_FAILED) {
      anv_gem_close(pool->device, new_bo.gem_handle);
      return vk_error(VK_ERROR_MEMORY_MAP_FAILED);
   }

   *bo = new_bo;

   VG(VALGRIND_MEMPOOL_ALLOC(pool, bo->map, size));

   return VK_SUCCESS;
}

void
anv_bo_pool_free(struct anv_bo_pool *pool, const struct anv_bo *bo_in)
{
   /* Make a copy in case the anv_bo happens to be storred in the BO */
   struct anv_bo bo = *bo_in;

   VG(VALGRIND_MEMPOOL_FREE(pool, bo.map));

   struct bo_pool_bo_link *link = bo.map;
   VG_NOACCESS_WRITE(&link->bo, bo);

   assert(util_is_power_of_two_or_zero(bo.size));
   const unsigned size_log2 = ilog2_round_up(bo.size);
   const unsigned bucket = size_log2 - 12;
   assert(bucket < ARRAY_SIZE(pool->free_list));

   anv_ptr_free_list_push(&pool->free_list[bucket], link);
}

// Scratch pool

void
anv_scratch_pool_init(struct anv_device *device, struct anv_scratch_pool *pool)
{
   memset(pool, 0, sizeof(*pool));
}

void
anv_scratch_pool_finish(struct anv_device *device, struct anv_scratch_pool *pool)
{
   for (unsigned s = 0; s < MESA_SHADER_STAGES; s++) {
      for (unsigned i = 0; i < 16; i++) {
         struct anv_scratch_bo *bo = &pool->bos[i][s];
         if (bo->exists > 0)
            anv_gem_close(device, bo->bo.gem_handle);
      }
   }
}

struct anv_bo *
anv_scratch_pool_alloc(struct anv_device *device, struct anv_scratch_pool *pool,
                       gl_shader_stage stage, unsigned per_thread_scratch)
{
   if (per_thread_scratch == 0)
      return NULL;

   unsigned scratch_size_log2 = ffs(per_thread_scratch / 2048);
   assert(scratch_size_log2 < 16);

   struct anv_scratch_bo *bo = &pool->bos[scratch_size_log2][stage];

   /* We can use "exists" to shortcut and ignore the critical section */
   if (bo->exists)
      return &bo->bo;

   pthread_mutex_lock(&device->mutex);

   __sync_synchronize();
   if (bo->exists) {
      pthread_mutex_unlock(&device->mutex);
      return &bo->bo;
   }

   const struct anv_physical_device *physical_device =
      &device->instance->physicalDevice;
   const struct gen_device_info *devinfo = &physical_device->info;

   const unsigned subslices = MAX2(physical_device->subslice_total, 1);

   unsigned scratch_ids_per_subslice;
   if (devinfo->is_haswell) {
      /* WaCSScratchSize:hsw
       *
       * Haswell's scratch space address calculation appears to be sparse
       * rather than tightly packed. The Thread ID has bits indicating
       * which subslice, EU within a subslice, and thread within an EU it
       * is. There's a maximum of two slices and two subslices, so these
       * can be stored with a single bit. Even though there are only 10 EUs
       * per subslice, this is stored in 4 bits, so there's an effective
       * maximum value of 16 EUs. Similarly, although there are only 7
       * threads per EU, this is stored in a 3 bit number, giving an
       * effective maximum value of 8 threads per EU.
       *
       * This means that we need to use 16 * 8 instead of 10 * 7 for the
       * number of threads per subslice.
       */
      scratch_ids_per_subslice = 16 * 8;
   } else if (devinfo->is_cherryview) {
      /* Cherryview devices have either 6 or 8 EUs per subslice, and each EU
       * has 7 threads. The 6 EU devices appear to calculate thread IDs as if
       * it had 8 EUs.
       */
      scratch_ids_per_subslice = 8 * 7;
   } else {
      scratch_ids_per_subslice = devinfo->max_cs_threads;
   }

   uint32_t max_threads[] = {
      [MESA_SHADER_VERTEX]           = devinfo->max_vs_threads,
      [MESA_SHADER_TESS_CTRL]        = devinfo->max_tcs_threads,
      [MESA_SHADER_TESS_EVAL]        = devinfo->max_tes_threads,
      [MESA_SHADER_GEOMETRY]         = devinfo->max_gs_threads,
      [MESA_SHADER_FRAGMENT]         = devinfo->max_wm_threads,
      [MESA_SHADER_COMPUTE]          = scratch_ids_per_subslice * subslices,
   };

   uint32_t size = per_thread_scratch * max_threads[stage];

   anv_bo_init_new(&bo->bo, device, size);

   /* Even though the Scratch base pointers in 3DSTATE_*S are 64 bits, they
    * are still relative to the general state base address.  When we emit
    * STATE_BASE_ADDRESS, we set general state base address to 0 and the size
    * to the maximum (1 page under 4GB).  This allows us to just place the
    * scratch buffers anywhere we wish in the bottom 32 bits of address space
    * and just set the scratch base pointer in 3DSTATE_*S using a relocation.
    * However, in order to do so, we need to ensure that the kernel does not
    * place the scratch BO above the 32-bit boundary.
    *
    * NOTE: Technically, it can't go "anywhere" because the top page is off
    * limits.  However, when EXEC_OBJECT_SUPPORTS_48B_ADDRESS is set, the
    * kernel allocates space using
    *
    *    end = min_t(u64, end, (1ULL << 32) - I915_GTT_PAGE_SIZE);
    *
    * so nothing will ever touch the top page.
    */
   assert(!(bo->bo.flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS));

   if (device->instance->physicalDevice.has_exec_async)
      bo->bo.flags |= EXEC_OBJECT_ASYNC;

   /* Set the exists last because it may be read by other threads */
   __sync_synchronize();
   bo->exists = true;

   pthread_mutex_unlock(&device->mutex);

   return &bo->bo;
}

struct anv_cached_bo {
   struct anv_bo bo;

   uint32_t refcount;
};

VkResult
anv_bo_cache_init(struct anv_bo_cache *cache)
{
   cache->bo_map = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
                                           _mesa_key_pointer_equal);
   if (!cache->bo_map)
      return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);

   if (pthread_mutex_init(&cache->mutex, NULL)) {
      _mesa_hash_table_destroy(cache->bo_map, NULL);
      return vk_errorf(NULL, NULL, VK_ERROR_OUT_OF_HOST_MEMORY,
                       "pthread_mutex_init failed: %m");
   }

   return VK_SUCCESS;
}

void
anv_bo_cache_finish(struct anv_bo_cache *cache)
{
   _mesa_hash_table_destroy(cache->bo_map, NULL);
   pthread_mutex_destroy(&cache->mutex);
}

static struct anv_cached_bo *
anv_bo_cache_lookup_locked(struct anv_bo_cache *cache, uint32_t gem_handle)
{
   struct hash_entry *entry =
      _mesa_hash_table_search(cache->bo_map,
                              (const void *)(uintptr_t)gem_handle);
   if (!entry)
      return NULL;

   struct anv_cached_bo *bo = (struct anv_cached_bo *)entry->data;
   assert(bo->bo.gem_handle == gem_handle);

   return bo;
}

UNUSED static struct anv_bo *
anv_bo_cache_lookup(struct anv_bo_cache *cache, uint32_t gem_handle)
{
   pthread_mutex_lock(&cache->mutex);

   struct anv_cached_bo *bo = anv_bo_cache_lookup_locked(cache, gem_handle);

   pthread_mutex_unlock(&cache->mutex);

   return bo ? &bo->bo : NULL;
}

VkResult
anv_bo_cache_alloc(struct anv_device *device,
                   struct anv_bo_cache *cache,
                   uint64_t size, struct anv_bo **bo_out)
{
   struct anv_cached_bo *bo =
      vk_alloc(&device->alloc, sizeof(struct anv_cached_bo), 8,
               VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
   if (!bo)
      return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);

   bo->refcount = 1;

   /* The kernel is going to give us whole pages anyway */
   size = align_u64(size, 4096);

   VkResult result = anv_bo_init_new(&bo->bo, device, size);
   if (result != VK_SUCCESS) {
      vk_free(&device->alloc, bo);
      return result;
   }

   assert(bo->bo.gem_handle);

   pthread_mutex_lock(&cache->mutex);

   _mesa_hash_table_insert(cache->bo_map,
                           (void *)(uintptr_t)bo->bo.gem_handle, bo);

   pthread_mutex_unlock(&cache->mutex);

   *bo_out = &bo->bo;

   return VK_SUCCESS;
}

VkResult
anv_bo_cache_import(struct anv_device *device,
                    struct anv_bo_cache *cache,
                    int fd, struct anv_bo **bo_out)
{
   pthread_mutex_lock(&cache->mutex);

   uint32_t gem_handle = anv_gem_fd_to_handle(device, fd);
   if (!gem_handle) {
      pthread_mutex_unlock(&cache->mutex);
      return vk_error(VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR);
   }

   struct anv_cached_bo *bo = anv_bo_cache_lookup_locked(cache, gem_handle);
   if (bo) {
      __sync_fetch_and_add(&bo->refcount, 1);
   } else {
      off_t size = lseek(fd, 0, SEEK_END);
      if (size == (off_t)-1) {
         anv_gem_close(device, gem_handle);
         pthread_mutex_unlock(&cache->mutex);
         return vk_error(VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR);
      }

      bo = vk_alloc(&device->alloc, sizeof(struct anv_cached_bo), 8,
                    VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
      if (!bo) {
         anv_gem_close(device, gem_handle);
         pthread_mutex_unlock(&cache->mutex);
         return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);
      }

      bo->refcount = 1;

      anv_bo_init(&bo->bo, gem_handle, size);

      _mesa_hash_table_insert(cache->bo_map, (void *)(uintptr_t)gem_handle, bo);
   }

   pthread_mutex_unlock(&cache->mutex);
   *bo_out = &bo->bo;

   return VK_SUCCESS;
}

VkResult
anv_bo_cache_export(struct anv_device *device,
                    struct anv_bo_cache *cache,
                    struct anv_bo *bo_in, int *fd_out)
{
   assert(anv_bo_cache_lookup(cache, bo_in->gem_handle) == bo_in);
   struct anv_cached_bo *bo = (struct anv_cached_bo *)bo_in;

   int fd = anv_gem_handle_to_fd(device, bo->bo.gem_handle);
   if (fd < 0)
      return vk_error(VK_ERROR_TOO_MANY_OBJECTS);

   *fd_out = fd;

   return VK_SUCCESS;
}

static bool
atomic_dec_not_one(uint32_t *counter)
{
   uint32_t old, val;

   val = *counter;
   while (1) {
      if (val == 1)
         return false;

      old = __sync_val_compare_and_swap(counter, val, val - 1);
      if (old == val)
         return true;

      val = old;
   }
}

void
anv_bo_cache_release(struct anv_device *device,
                     struct anv_bo_cache *cache,
                     struct anv_bo *bo_in)
{
   assert(anv_bo_cache_lookup(cache, bo_in->gem_handle) == bo_in);
   struct anv_cached_bo *bo = (struct anv_cached_bo *)bo_in;

   /* Try to decrement the counter but don't go below one.  If this succeeds
    * then the refcount has been decremented and we are not the last
    * reference.
    */
   if (atomic_dec_not_one(&bo->refcount))
      return;

   pthread_mutex_lock(&cache->mutex);

   /* We are probably the last reference since our attempt to decrement above
    * failed.  However, we can't actually know until we are inside the mutex.
    * Otherwise, someone could import the BO between the decrement and our
    * taking the mutex.
    */
   if (unlikely(__sync_sub_and_fetch(&bo->refcount, 1) > 0)) {
      /* Turns out we're not the last reference.  Unlock and bail. */
      pthread_mutex_unlock(&cache->mutex);
      return;
   }

   struct hash_entry *entry =
      _mesa_hash_table_search(cache->bo_map,
                              (const void *)(uintptr_t)bo->bo.gem_handle);
   assert(entry);
   _mesa_hash_table_remove(cache->bo_map, entry);

   if (bo->bo.map)
      anv_gem_munmap(bo->bo.map, bo->bo.size);

   anv_gem_close(device, bo->bo.gem_handle);

   /* Don't unlock until we've actually closed the BO.  The whole point of
    * the BO cache is to ensure that we correctly handle races with creating
    * and releasing GEM handles and we don't want to let someone import the BO
    * again between mutex unlock and closing the GEM handle.
    */
   pthread_mutex_unlock(&cache->mutex);

   vk_free(&device->alloc, bo);
}