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
|
/*****************************************************************************
Copyright (c) 2006, 2010, Innobase Oy. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA
*****************************************************************************/
/**************************************************//**
@file buf/buf0buddy.c
Binary buddy allocator for compressed pages
Created December 2006 by Marko Makela
*******************************************************/
#define THIS_MODULE
#include "buf0buddy.h"
#ifdef UNIV_NONINL
# include "buf0buddy.ic"
#endif
#undef THIS_MODULE
#include "buf0buf.h"
#include "buf0lru.h"
#include "buf0flu.h"
#include "page0zip.h"
/**********************************************************************//**
Get the offset of the buddy of a compressed page frame.
@return the buddy relative of page */
UNIV_INLINE
byte*
buf_buddy_get(
/*==========*/
byte* page, /*!< in: compressed page */
ulint size) /*!< in: page size in bytes */
{
ut_ad(ut_is_2pow(size));
ut_ad(size >= BUF_BUDDY_LOW);
ut_ad(size < BUF_BUDDY_HIGH);
ut_ad(!ut_align_offset(page, size));
if (((ulint) page) & size) {
return(page - size);
} else {
return(page + size);
}
}
/**********************************************************************//**
Add a block to the head of the appropriate buddy free list. */
UNIV_INLINE
void
buf_buddy_add_to_free(
/*==================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
buf_page_t* bpage, /*!< in,own: block to be freed */
ulint i) /*!< in: index of
buf_pool->zip_free[] */
{
#ifdef UNIV_DEBUG_VALGRIND
buf_page_t* b = UT_LIST_GET_FIRST(buf_pool->zip_free[i]);
if (b) UNIV_MEM_VALID(b, BUF_BUDDY_LOW << i);
#endif /* UNIV_DEBUG_VALGRIND */
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_FREE);
ut_ad(buf_pool->zip_free[i].start != bpage);
UT_LIST_ADD_FIRST(list, buf_pool->zip_free[i], bpage);
#ifdef UNIV_DEBUG_VALGRIND
if (b) UNIV_MEM_FREE(b, BUF_BUDDY_LOW << i);
UNIV_MEM_ASSERT_AND_FREE(bpage, BUF_BUDDY_LOW << i);
#endif /* UNIV_DEBUG_VALGRIND */
}
/**********************************************************************//**
Remove a block from the appropriate buddy free list. */
UNIV_INLINE
void
buf_buddy_remove_from_free(
/*=======================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
buf_page_t* bpage, /*!< in: block to be removed */
ulint i) /*!< in: index of
buf_pool->zip_free[] */
{
#ifdef UNIV_DEBUG_VALGRIND
buf_page_t* prev = UT_LIST_GET_PREV(list, bpage);
buf_page_t* next = UT_LIST_GET_NEXT(list, bpage);
if (prev) UNIV_MEM_VALID(prev, BUF_BUDDY_LOW << i);
if (next) UNIV_MEM_VALID(next, BUF_BUDDY_LOW << i);
ut_ad(!prev || buf_page_get_state(prev) == BUF_BLOCK_ZIP_FREE);
ut_ad(!next || buf_page_get_state(next) == BUF_BLOCK_ZIP_FREE);
#endif /* UNIV_DEBUG_VALGRIND */
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_FREE);
UT_LIST_REMOVE(list, buf_pool->zip_free[i], bpage);
#ifdef UNIV_DEBUG_VALGRIND
if (prev) UNIV_MEM_FREE(prev, BUF_BUDDY_LOW << i);
if (next) UNIV_MEM_FREE(next, BUF_BUDDY_LOW << i);
#endif /* UNIV_DEBUG_VALGRIND */
}
/**********************************************************************//**
Try to allocate a block from buf_pool->zip_free[].
@return allocated block, or NULL if buf_pool->zip_free[] was empty */
static
void*
buf_buddy_alloc_zip(
/*================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
ulint i) /*!< in: index of buf_pool->zip_free[] */
{
buf_page_t* bpage;
ut_ad(buf_pool_mutex_own(buf_pool));
ut_a(i < BUF_BUDDY_SIZES);
#ifndef UNIV_DEBUG_VALGRIND
/* Valgrind would complain about accessing free memory. */
ut_d(UT_LIST_VALIDATE(list, buf_page_t, buf_pool->zip_free[i],
ut_ad(buf_page_get_state(ut_list_node_313)
== BUF_BLOCK_ZIP_FREE)));
#endif /* !UNIV_DEBUG_VALGRIND */
bpage = UT_LIST_GET_FIRST(buf_pool->zip_free[i]);
if (bpage) {
UNIV_MEM_VALID(bpage, BUF_BUDDY_LOW << i);
ut_a(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_FREE);
buf_buddy_remove_from_free(buf_pool, bpage, i);
} else if (i + 1 < BUF_BUDDY_SIZES) {
/* Attempt to split. */
bpage = buf_buddy_alloc_zip(buf_pool, i + 1);
if (bpage) {
buf_page_t* buddy = (buf_page_t*)
(((char*) bpage) + (BUF_BUDDY_LOW << i));
ut_ad(!buf_pool_contains_zip(buf_pool, buddy));
ut_d(memset(buddy, i, BUF_BUDDY_LOW << i));
buddy->state = BUF_BLOCK_ZIP_FREE;
buf_buddy_add_to_free(buf_pool, buddy, i);
}
}
#ifdef UNIV_DEBUG
if (bpage) {
memset(bpage, ~i, BUF_BUDDY_LOW << i);
}
#endif /* UNIV_DEBUG */
UNIV_MEM_ALLOC(bpage, BUF_BUDDY_SIZES << i);
return(bpage);
}
/**********************************************************************//**
Deallocate a buffer frame of UNIV_PAGE_SIZE. */
static
void
buf_buddy_block_free(
/*=================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
void* buf) /*!< in: buffer frame to deallocate */
{
const ulint fold = BUF_POOL_ZIP_FOLD_PTR(buf);
buf_page_t* bpage;
buf_block_t* block;
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(!mutex_own(&buf_pool->zip_mutex));
ut_a(!ut_align_offset(buf, UNIV_PAGE_SIZE));
HASH_SEARCH(hash, buf_pool->zip_hash, fold, buf_page_t*, bpage,
ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_MEMORY
&& bpage->in_zip_hash && !bpage->in_page_hash),
((buf_block_t*) bpage)->frame == buf);
ut_a(bpage);
ut_a(buf_page_get_state(bpage) == BUF_BLOCK_MEMORY);
ut_ad(!bpage->in_page_hash);
ut_ad(bpage->in_zip_hash);
ut_d(bpage->in_zip_hash = FALSE);
HASH_DELETE(buf_page_t, hash, buf_pool->zip_hash, fold, bpage);
ut_d(memset(buf, 0, UNIV_PAGE_SIZE));
UNIV_MEM_INVALID(buf, UNIV_PAGE_SIZE);
block = (buf_block_t*) bpage;
mutex_enter(&block->mutex);
buf_LRU_block_free_non_file_page(block);
mutex_exit(&block->mutex);
ut_ad(buf_pool->buddy_n_frames > 0);
ut_d(buf_pool->buddy_n_frames--);
}
/**********************************************************************//**
Allocate a buffer block to the buddy allocator. */
static
void
buf_buddy_block_register(
/*=====================*/
buf_block_t* block) /*!< in: buffer frame to allocate */
{
buf_pool_t* buf_pool = buf_pool_from_block(block);
const ulint fold = BUF_POOL_ZIP_FOLD(block);
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(!mutex_own(&buf_pool->zip_mutex));
ut_ad(buf_block_get_state(block) == BUF_BLOCK_READY_FOR_USE);
buf_block_set_state(block, BUF_BLOCK_MEMORY);
ut_a(block->frame);
ut_a(!ut_align_offset(block->frame, UNIV_PAGE_SIZE));
ut_ad(!block->page.in_page_hash);
ut_ad(!block->page.in_zip_hash);
ut_d(block->page.in_zip_hash = TRUE);
HASH_INSERT(buf_page_t, hash, buf_pool->zip_hash, fold, &block->page);
ut_d(buf_pool->buddy_n_frames++);
}
/**********************************************************************//**
Allocate a block from a bigger object.
@return allocated block */
static
void*
buf_buddy_alloc_from(
/*=================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
void* buf, /*!< in: a block that is free to use */
ulint i, /*!< in: index of
buf_pool->zip_free[] */
ulint j) /*!< in: size of buf as an index
of buf_pool->zip_free[] */
{
ulint offs = BUF_BUDDY_LOW << j;
ut_ad(j <= BUF_BUDDY_SIZES);
ut_ad(j >= i);
ut_ad(!ut_align_offset(buf, offs));
/* Add the unused parts of the block to the free lists. */
while (j > i) {
buf_page_t* bpage;
offs >>= 1;
j--;
bpage = (buf_page_t*) ((byte*) buf + offs);
ut_d(memset(bpage, j, BUF_BUDDY_LOW << j));
bpage->state = BUF_BLOCK_ZIP_FREE;
#ifndef UNIV_DEBUG_VALGRIND
/* Valgrind would complain about accessing free memory. */
ut_d(UT_LIST_VALIDATE(list, buf_page_t, buf_pool->zip_free[i],
ut_ad(buf_page_get_state(
ut_list_node_313)
== BUF_BLOCK_ZIP_FREE)));
#endif /* !UNIV_DEBUG_VALGRIND */
buf_buddy_add_to_free(buf_pool, bpage, j);
}
return(buf);
}
/**********************************************************************//**
Allocate a block. The thread calling this function must hold
buf_pool->mutex and must not hold buf_pool->zip_mutex or any block->mutex.
The buf_pool->mutex may only be released and reacquired if lru != NULL.
@return allocated block, possibly NULL if lru==NULL */
UNIV_INTERN
void*
buf_buddy_alloc_low(
/*================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
ulint i, /*!< in: index of buf_pool->zip_free[],
or BUF_BUDDY_SIZES */
ibool* lru) /*!< in: pointer to a variable that
will be assigned TRUE if storage was
allocated from the LRU list and
buf_pool->mutex was temporarily
released, or NULL if the LRU list
should not be used */
{
buf_block_t* block;
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(!mutex_own(&buf_pool->zip_mutex));
if (i < BUF_BUDDY_SIZES) {
/* Try to allocate from the buddy system. */
block = buf_buddy_alloc_zip(buf_pool, i);
if (block) {
goto func_exit;
}
}
/* Try allocating from the buf_pool->free list. */
block = buf_LRU_get_free_only(buf_pool);
if (block) {
goto alloc_big;
}
if (!lru) {
return(NULL);
}
/* Try replacing an uncompressed page in the buffer pool. */
buf_pool_mutex_exit(buf_pool);
block = buf_LRU_get_free_block(buf_pool);
*lru = TRUE;
buf_pool_mutex_enter(buf_pool);
alloc_big:
buf_buddy_block_register(block);
block = buf_buddy_alloc_from(
buf_pool, block->frame, i, BUF_BUDDY_SIZES);
func_exit:
buf_pool->buddy_stat[i].used++;
return(block);
}
/**********************************************************************//**
Try to relocate the control block of a compressed page.
@return TRUE if relocated */
static
ibool
buf_buddy_relocate_block(
/*=====================*/
buf_page_t* bpage, /*!< in: block to relocate */
buf_page_t* dpage) /*!< in: free block to relocate to */
{
buf_page_t* b;
buf_pool_t* buf_pool = buf_pool_from_bpage(bpage);
ut_ad(buf_pool_mutex_own(buf_pool));
switch (buf_page_get_state(bpage)) {
case BUF_BLOCK_ZIP_FREE:
case BUF_BLOCK_NOT_USED:
case BUF_BLOCK_READY_FOR_USE:
case BUF_BLOCK_FILE_PAGE:
case BUF_BLOCK_MEMORY:
case BUF_BLOCK_REMOVE_HASH:
ut_error;
case BUF_BLOCK_ZIP_DIRTY:
/* Cannot relocate dirty pages. */
return(FALSE);
case BUF_BLOCK_ZIP_PAGE:
break;
}
mutex_enter(&buf_pool->zip_mutex);
if (!buf_page_can_relocate(bpage)) {
mutex_exit(&buf_pool->zip_mutex);
return(FALSE);
}
buf_relocate(bpage, dpage);
ut_d(bpage->state = BUF_BLOCK_ZIP_FREE);
/* relocate buf_pool->zip_clean */
b = UT_LIST_GET_PREV(list, dpage);
UT_LIST_REMOVE(list, buf_pool->zip_clean, dpage);
if (b) {
UT_LIST_INSERT_AFTER(list, buf_pool->zip_clean, b, dpage);
} else {
UT_LIST_ADD_FIRST(list, buf_pool->zip_clean, dpage);
}
UNIV_MEM_INVALID(bpage, sizeof *bpage);
mutex_exit(&buf_pool->zip_mutex);
return(TRUE);
}
/**********************************************************************//**
Try to relocate a block.
@return TRUE if relocated */
static
ibool
buf_buddy_relocate(
/*===============*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
void* src, /*!< in: block to relocate */
void* dst, /*!< in: free block to relocate to */
ulint i) /*!< in: index of
buf_pool->zip_free[] */
{
buf_page_t* bpage;
const ulint size = BUF_BUDDY_LOW << i;
ullint usec = ut_time_us(NULL);
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(!mutex_own(&buf_pool->zip_mutex));
ut_ad(!ut_align_offset(src, size));
ut_ad(!ut_align_offset(dst, size));
UNIV_MEM_ASSERT_W(dst, size);
/* We assume that all memory from buf_buddy_alloc()
is used for either compressed pages or buf_page_t
objects covering compressed pages. */
/* We look inside the allocated objects returned by
buf_buddy_alloc() and assume that anything of
PAGE_ZIP_MIN_SIZE or larger is a compressed page that contains
a valid space_id and page_no in the page header. Should the
fields be invalid, we will be unable to relocate the block.
We also assume that anything that fits sizeof(buf_page_t)
actually is a properly initialized buf_page_t object. */
if (size >= PAGE_ZIP_MIN_SIZE) {
/* This is a compressed page. */
mutex_t* mutex;
/* The src block may be split into smaller blocks,
some of which may be free. Thus, the
mach_read_from_4() calls below may attempt to read
from free memory. The memory is "owned" by the buddy
allocator (and it has been allocated from the buffer
pool), so there is nothing wrong about this. The
mach_read_from_4() calls here will only trigger bogus
Valgrind memcheck warnings in UNIV_DEBUG_VALGRIND builds. */
ulint space = mach_read_from_4(
(const byte*) src + FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID);
ulint page_no = mach_read_from_4(
(const byte*) src + FIL_PAGE_OFFSET);
/* Suppress Valgrind warnings about conditional jump
on uninitialized value. */
UNIV_MEM_VALID(&space, sizeof space);
UNIV_MEM_VALID(&page_no, sizeof page_no);
bpage = buf_page_hash_get(buf_pool, space, page_no);
if (!bpage || bpage->zip.data != src) {
/* The block has probably been freshly
allocated by buf_LRU_get_free_block() but not
added to buf_pool->page_hash yet. Obviously,
it cannot be relocated. */
return(FALSE);
}
ut_ad(!buf_pool_watch_is_sentinel(buf_pool, bpage));
if (page_zip_get_size(&bpage->zip) != size) {
/* The block is of different size. We would
have to relocate all blocks covered by src.
For the sake of simplicity, give up. */
ut_ad(page_zip_get_size(&bpage->zip) < size);
return(FALSE);
}
/* The block must have been allocated, but it may
contain uninitialized data. */
UNIV_MEM_ASSERT_W(src, size);
mutex = buf_page_get_mutex(bpage);
mutex_enter(mutex);
if (buf_page_can_relocate(bpage)) {
/* Relocate the compressed page. */
ut_a(bpage->zip.data == src);
memcpy(dst, src, size);
bpage->zip.data = dst;
mutex_exit(mutex);
success:
UNIV_MEM_INVALID(src, size);
{
buf_buddy_stat_t* buddy_stat
= &buf_pool->buddy_stat[i];
buddy_stat->relocated++;
buddy_stat->relocated_usec
+= ut_time_us(NULL) - usec;
}
return(TRUE);
}
mutex_exit(mutex);
} else if (i == buf_buddy_get_slot(sizeof(buf_page_t))) {
/* This must be a buf_page_t object. */
#if UNIV_WORD_SIZE == 4
/* On 32-bit systems, there is no padding in
buf_page_t. On other systems, Valgrind could complain
about uninitialized pad bytes. */
UNIV_MEM_ASSERT_RW(src, size);
#endif
if (buf_buddy_relocate_block(src, dst)) {
goto success;
}
}
return(FALSE);
}
/**********************************************************************//**
Deallocate a block. */
UNIV_INTERN
void
buf_buddy_free_low(
/*===============*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
void* buf, /*!< in: block to be freed, must not be
pointed to by the buffer pool */
ulint i) /*!< in: index of buf_pool->zip_free[],
or BUF_BUDDY_SIZES */
{
buf_page_t* bpage;
buf_page_t* buddy;
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(!mutex_own(&buf_pool->zip_mutex));
ut_ad(i <= BUF_BUDDY_SIZES);
ut_ad(buf_pool->buddy_stat[i].used > 0);
buf_pool->buddy_stat[i].used--;
recombine:
UNIV_MEM_ASSERT_AND_ALLOC(buf, BUF_BUDDY_LOW << i);
ut_d(((buf_page_t*) buf)->state = BUF_BLOCK_ZIP_FREE);
if (i == BUF_BUDDY_SIZES) {
buf_buddy_block_free(buf_pool, buf);
return;
}
ut_ad(i < BUF_BUDDY_SIZES);
ut_ad(buf == ut_align_down(buf, BUF_BUDDY_LOW << i));
ut_ad(!buf_pool_contains_zip(buf_pool, buf));
/* Try to combine adjacent blocks. */
buddy = (buf_page_t*) buf_buddy_get(((byte*) buf), BUF_BUDDY_LOW << i);
#ifndef UNIV_DEBUG_VALGRIND
/* Valgrind would complain about accessing free memory. */
if (buddy->state != BUF_BLOCK_ZIP_FREE) {
goto buddy_nonfree;
}
/* The field buddy->state can only be trusted for free blocks.
If buddy->state == BUF_BLOCK_ZIP_FREE, the block is free if
it is in the free list. */
#endif /* !UNIV_DEBUG_VALGRIND */
for (bpage = UT_LIST_GET_FIRST(buf_pool->zip_free[i]); bpage; ) {
UNIV_MEM_VALID(bpage, BUF_BUDDY_LOW << i);
ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_FREE);
if (bpage == buddy) {
buddy_free:
/* The buddy is free: recombine */
buf_buddy_remove_from_free(buf_pool, bpage, i);
buddy_free2:
ut_ad(buf_page_get_state(buddy) == BUF_BLOCK_ZIP_FREE);
ut_ad(!buf_pool_contains_zip(buf_pool, buddy));
i++;
buf = ut_align_down(buf, BUF_BUDDY_LOW << i);
goto recombine;
}
ut_a(bpage != buf);
{
buf_page_t* next = UT_LIST_GET_NEXT(list, bpage);
UNIV_MEM_ASSERT_AND_FREE(bpage, BUF_BUDDY_LOW << i);
bpage = next;
}
}
#ifndef UNIV_DEBUG_VALGRIND
buddy_nonfree:
/* Valgrind would complain about accessing free memory. */
ut_d(UT_LIST_VALIDATE(list, buf_page_t, buf_pool->zip_free[i],
ut_ad(buf_page_get_state(ut_list_node_313)
== BUF_BLOCK_ZIP_FREE)));
#endif /* UNIV_DEBUG_VALGRIND */
/* The buddy is not free. Is there a free block of this size? */
bpage = UT_LIST_GET_FIRST(buf_pool->zip_free[i]);
if (bpage) {
/* Remove the block from the free list, because a successful
buf_buddy_relocate() will overwrite bpage->list. */
UNIV_MEM_VALID(bpage, BUF_BUDDY_LOW << i);
buf_buddy_remove_from_free(buf_pool, bpage, i);
/* Try to relocate the buddy of buf to the free block. */
if (buf_buddy_relocate(buf_pool, buddy, bpage, i)) {
ut_d(buddy->state = BUF_BLOCK_ZIP_FREE);
goto buddy_free2;
}
buf_buddy_add_to_free(buf_pool, bpage, i);
/* Try to relocate the buddy of the free block to buf. */
buddy = (buf_page_t*) buf_buddy_get(((byte*) bpage),
BUF_BUDDY_LOW << i);
#ifndef UNIV_DEBUG_VALGRIND
/* Valgrind would complain about accessing free memory. */
/* The buddy must not be (completely) free, because we
always recombine adjacent free blocks.
(Parts of the buddy can be free in
buf_pool->zip_free[j] with j < i.) */
ut_d(UT_LIST_VALIDATE(list, buf_page_t, buf_pool->zip_free[i],
ut_ad(buf_page_get_state(
ut_list_node_313)
== BUF_BLOCK_ZIP_FREE
&& ut_list_node_313 != buddy)));
#endif /* !UNIV_DEBUG_VALGRIND */
if (buf_buddy_relocate(buf_pool, buddy, buf, i)) {
buf = bpage;
UNIV_MEM_VALID(bpage, BUF_BUDDY_LOW << i);
ut_d(buddy->state = BUF_BLOCK_ZIP_FREE);
goto buddy_free;
}
}
/* Free the block to the buddy list. */
bpage = buf;
#ifdef UNIV_DEBUG
if (i < buf_buddy_get_slot(PAGE_ZIP_MIN_SIZE)) {
/* This area has most likely been allocated for at
least one compressed-only block descriptor. Check
that there are no live objects in the area. This is
not a complete check: it may yield false positives as
well as false negatives. Also, due to buddy blocks
being recombined, it is possible (although unlikely)
that this branch is never reached. */
char* c;
# ifndef UNIV_DEBUG_VALGRIND
/* Valgrind would complain about accessing
uninitialized memory. Besides, Valgrind performs a
more exhaustive check, at every memory access. */
const buf_page_t* b = buf;
const buf_page_t* const b_end = (buf_page_t*)
((char*) b + (BUF_BUDDY_LOW << i));
for (; b < b_end; b++) {
/* Avoid false positives (and cause false
negatives) by checking for b->space < 1000. */
if ((b->state == BUF_BLOCK_ZIP_PAGE
|| b->state == BUF_BLOCK_ZIP_DIRTY)
&& b->space > 0 && b->space < 1000) {
fprintf(stderr,
"buddy dirty %p %u (%u,%u) %p,%lu\n",
(void*) b,
b->state, b->space, b->offset,
buf, i);
}
}
# endif /* !UNIV_DEBUG_VALGRIND */
/* Scramble the block. This should make any pointers
invalid and trigger a segmentation violation. Because
the scrambling can be reversed, it may be possible to
track down the object pointing to the freed data by
dereferencing the unscrambled bpage->LRU or
bpage->list pointers. */
for (c = (char*) buf + (BUF_BUDDY_LOW << i);
c-- > (char*) buf; ) {
*c = ~*c ^ i;
}
} else {
/* Fill large blocks with a constant pattern. */
memset(bpage, i, BUF_BUDDY_LOW << i);
}
#endif /* UNIV_DEBUG */
bpage->state = BUF_BLOCK_ZIP_FREE;
buf_buddy_add_to_free(buf_pool, bpage, i);
}
|