Line data Source code
1 : /******************************************************************************
2 : *
3 : * Project: GDAL Core
4 : * Purpose: Implementation of GDALRasterBlock class and related global
5 : * raster block cache management.
6 : * Author: Frank Warmerdam, warmerdam@pobox.com
7 : *
8 : **********************************************************************
9 : * Copyright (c) 1998, Frank Warmerdam <warmerdam@pobox.com>
10 : * Copyright (c) 2008-2013, Even Rouault <even dot rouault at spatialys.com>
11 : *
12 : * SPDX-License-Identifier: MIT
13 : ****************************************************************************/
14 :
15 : #include "cpl_port.h"
16 : #include "gdal.h"
17 : #include "gdal_priv.h"
18 :
19 : #include <algorithm>
20 : #include <climits>
21 : #include <cstring>
22 : #include <mutex>
23 :
24 : #include "cpl_atomic_ops.h"
25 : #include "cpl_conv.h"
26 : #include "cpl_error.h"
27 : #include "cpl_multiproc.h"
28 : #include "cpl_string.h"
29 : #include "cpl_vsi.h"
30 :
31 : // Will later be overridden by the default 5% if GDAL_CACHEMAX not defined.
32 : static GIntBig nCacheMax = 40 * 1024 * 1024;
33 : static GIntBig nCacheUsed = 0;
34 :
35 : static GDALRasterBlock *poOldest = nullptr; // Tail.
36 : static GDALRasterBlock *poNewest = nullptr; // Head.
37 :
38 : static int nDisableDirtyBlockFlushCounter = 0;
39 :
40 : #if 0
41 : static CPLMutex *hRBLock = nullptr;
42 : #define INITIALIZE_LOCK CPLMutexHolderD(&hRBLock)
43 : #define TAKE_LOCK CPLMutexHolderOptionalLockD(hRBLock)
44 : #define DESTROY_LOCK CPLDestroyMutex(hRBLock)
45 : #else
46 :
47 : static CPLLock *hRBLock = nullptr;
48 : static bool bDebugContention = false;
49 : static bool bSleepsForBockCacheDebug = false;
50 :
51 5073 : static CPLLockType GetLockType()
52 : {
53 : static int nLockType = -1;
54 5073 : if (nLockType < 0)
55 : {
56 : const char *pszLockType =
57 566 : CPLGetConfigOption("GDAL_RB_LOCK_TYPE", "ADAPTIVE");
58 566 : if (EQUAL(pszLockType, "ADAPTIVE"))
59 564 : nLockType = LOCK_ADAPTIVE_MUTEX;
60 2 : else if (EQUAL(pszLockType, "RECURSIVE"))
61 0 : nLockType = LOCK_RECURSIVE_MUTEX;
62 2 : else if (EQUAL(pszLockType, "SPIN"))
63 2 : nLockType = LOCK_SPIN;
64 : else
65 : {
66 0 : CPLError(
67 : CE_Warning, CPLE_NotSupported,
68 : "GDAL_RB_LOCK_TYPE=%s not supported. Falling back to ADAPTIVE",
69 : pszLockType);
70 0 : nLockType = LOCK_ADAPTIVE_MUTEX;
71 : }
72 566 : bDebugContention = CPLTestBool(
73 : CPLGetConfigOption("GDAL_RB_LOCK_DEBUG_CONTENTION", "NO"));
74 : }
75 5073 : return static_cast<CPLLockType>(nLockType);
76 : }
77 :
78 : #define INITIALIZE_LOCK \
79 : CPLLockHolderD(&hRBLock, GetLockType()); \
80 : CPLLockSetDebugPerf(hRBLock, bDebugContention)
81 : #define TAKE_LOCK CPLLockHolderOptionalLockD(hRBLock)
82 : #define DESTROY_LOCK CPLDestroyLock(hRBLock)
83 :
84 : #endif
85 :
86 : // #define ENABLE_DEBUG
87 :
88 : /************************************************************************/
89 : /* GDALSetCacheMax() */
90 : /************************************************************************/
91 :
92 : /**
93 : * \brief Set maximum cache memory.
94 : *
95 : * This function sets the maximum amount of memory that GDAL is permitted
96 : * to use for GDALRasterBlock caching. The unit of the value is bytes.
97 : *
98 : * The maximum value is 2GB, due to the use of a signed 32 bit integer.
99 : * Use GDALSetCacheMax64() to be able to set a higher value.
100 : *
101 : * @param nNewSizeInBytes the maximum number of bytes for caching.
102 : */
103 :
104 15 : void CPL_STDCALL GDALSetCacheMax(int nNewSizeInBytes)
105 :
106 : {
107 15 : GDALSetCacheMax64(nNewSizeInBytes);
108 15 : }
109 :
110 : /************************************************************************/
111 : /* GDALSetCacheMax64() */
112 : /************************************************************************/
113 :
114 : /**
115 : * \brief Set maximum cache memory.
116 : *
117 : * This function sets the maximum amount of memory that GDAL is permitted
118 : * to use for GDALRasterBlock caching. The unit of the value is bytes.
119 : *
120 : * Note: On 32 bit platforms, the maximum amount of memory that can be addressed
121 : * by a process might be 2 GB or 3 GB, depending on the operating system
122 : * capabilities. This function will not make any attempt to check the
123 : * consistency of the passed value with the effective capabilities of the OS.
124 : *
125 : * @param nNewSizeInBytes the maximum number of bytes for caching.
126 : *
127 : * @since GDAL 1.8.0
128 : */
129 :
130 91 : void CPL_STDCALL GDALSetCacheMax64(GIntBig nNewSizeInBytes)
131 :
132 : {
133 : #if 0
134 : if( nNewSizeInBytes == 12346789 )
135 : {
136 : GDALRasterBlock::DumpAll();
137 : return;
138 : }
139 : #endif
140 :
141 : // To force one-time initialization of nCacheMax if not already done
142 91 : GDALGetCacheMax64();
143 91 : nCacheMax = nNewSizeInBytes;
144 :
145 : /* -------------------------------------------------------------------- */
146 : /* Flush blocks till we are under the new limit or till we */
147 : /* can't seem to flush anymore. */
148 : /* -------------------------------------------------------------------- */
149 4295 : while (nCacheUsed > nCacheMax)
150 : {
151 4204 : const GIntBig nOldCacheUsed = nCacheUsed;
152 :
153 4204 : GDALFlushCacheBlock();
154 :
155 4204 : if (nCacheUsed == nOldCacheUsed)
156 0 : break;
157 : }
158 91 : }
159 :
160 : /************************************************************************/
161 : /* GDALGetCacheMax() */
162 : /************************************************************************/
163 :
164 : /**
165 : * \brief Get maximum cache memory.
166 : *
167 : * Gets the maximum amount of memory available to the GDALRasterBlock
168 : * caching system for caching GDAL read/write imagery.
169 : *
170 : * The first type this function is called, it will read the GDAL_CACHEMAX
171 : * configuration option to initialize the maximum cache memory.
172 : * Starting with GDAL 2.1, the value can be expressed as x% of the usable
173 : * physical RAM (which may potentially be used by other processes). Otherwise
174 : * it is expected to be a value in MB.
175 : *
176 : * This function cannot return a value higher than 2 GB. Use
177 : * GDALGetCacheMax64() to get a non-truncated value.
178 : *
179 : * @return maximum in bytes.
180 : */
181 :
182 1 : int CPL_STDCALL GDALGetCacheMax()
183 : {
184 1 : GIntBig nRes = GDALGetCacheMax64();
185 1 : if (nRes > INT_MAX)
186 : {
187 0 : CPLErrorOnce(CE_Warning, CPLE_AppDefined,
188 : "Cache max value doesn't fit on a 32 bit integer. "
189 : "Call GDALGetCacheMax64() instead");
190 0 : nRes = INT_MAX;
191 : }
192 1 : return static_cast<int>(nRes);
193 : }
194 :
195 : /************************************************************************/
196 : /* GDALGetCacheMax64() */
197 : /************************************************************************/
198 :
199 : /**
200 : * \brief Get maximum cache memory.
201 : *
202 : * Gets the maximum amount of memory available to the GDALRasterBlock
203 : * caching system for caching GDAL read/write imagery.
204 : *
205 : * The first time this function is called, it will read the GDAL_CACHEMAX
206 : * configuration option to initialize the maximum cache memory.
207 : * Starting with GDAL 2.1, the value can be expressed as x% of the usable
208 : * physical RAM (which may potentially be used by other processes). Starting
209 : * with GDAL 3.11, the value can include units of memory. If not units are
210 : * provided the value is assumed to be in MB.
211 : *
212 : * @return maximum in bytes.
213 : *
214 : * @since GDAL 1.8.0
215 : */
216 :
217 4100020 : GIntBig CPL_STDCALL GDALGetCacheMax64()
218 : {
219 : static std::once_flag flagSetupGDALGetCacheMax64;
220 4100020 : std::call_once(
221 : flagSetupGDALGetCacheMax64,
222 566 : []()
223 : {
224 : {
225 566 : INITIALIZE_LOCK;
226 : }
227 566 : bSleepsForBockCacheDebug =
228 566 : CPLTestBool(CPLGetConfigOption("GDAL_DEBUG_BLOCK_CACHE", "NO"));
229 :
230 566 : const char *pszCacheMax = CPLGetConfigOption("GDAL_CACHEMAX", "5%");
231 : GIntBig nNewCacheMax;
232 566 : bool bUnitSpecified = false;
233 :
234 566 : if (CPLParseMemorySize(pszCacheMax, &nNewCacheMax,
235 566 : &bUnitSpecified) != CE_None)
236 : {
237 0 : CPLError(CE_Failure, CPLE_NotSupported,
238 : "Invalid value for GDAL_CACHEMAX. "
239 : "Using default value.");
240 0 : if (CPLParseMemorySize("5%", &nNewCacheMax, &bUnitSpecified) !=
241 : CE_None)
242 : {
243 : // This means that usable physical RAM could not be determined.
244 0 : nNewCacheMax = nCacheMax;
245 : }
246 : }
247 :
248 566 : if (!bUnitSpecified && nNewCacheMax < 100000)
249 : {
250 : // Assume MB
251 5 : nNewCacheMax *= (1024 * 1024);
252 : }
253 :
254 566 : nCacheMax = nNewCacheMax;
255 566 : CPLDebug("GDAL", "GDAL_CACHEMAX = " CPL_FRMT_GIB " MB",
256 : nCacheMax / (1024 * 1024));
257 566 : });
258 :
259 4099960 : return nCacheMax;
260 : }
261 :
262 : /************************************************************************/
263 : /* GDALGetCacheUsed() */
264 : /************************************************************************/
265 :
266 : /**
267 : * \brief Get cache memory used.
268 : *
269 : * @return the number of bytes of memory currently in use by the
270 : * GDALRasterBlock memory caching.
271 : */
272 :
273 0 : int CPL_STDCALL GDALGetCacheUsed()
274 : {
275 0 : if (nCacheUsed > INT_MAX)
276 : {
277 0 : CPLErrorOnce(CE_Warning, CPLE_AppDefined,
278 : "Cache used value doesn't fit on a 32 bit integer. "
279 : "Call GDALGetCacheUsed64() instead");
280 0 : return INT_MAX;
281 : }
282 0 : return static_cast<int>(nCacheUsed);
283 : }
284 :
285 : /************************************************************************/
286 : /* GDALGetCacheUsed64() */
287 : /************************************************************************/
288 :
289 : /**
290 : * \brief Get cache memory used.
291 : *
292 : * @return the number of bytes of memory currently in use by the
293 : * GDALRasterBlock memory caching.
294 : *
295 : * @since GDAL 1.8.0
296 : */
297 :
298 17 : GIntBig CPL_STDCALL GDALGetCacheUsed64()
299 : {
300 17 : return nCacheUsed;
301 : }
302 :
303 : /************************************************************************/
304 : /* GDALFlushCacheBlock() */
305 : /* */
306 : /* The workhorse of cache management! */
307 : /************************************************************************/
308 :
309 : /**
310 : * \brief Try to flush one cached raster block
311 : *
312 : * This function will search the first unlocked raster block and will
313 : * flush it to release the associated memory.
314 : *
315 : * @return TRUE if one block was flushed, FALSE if there are no cached blocks
316 : * or if they are currently locked.
317 : */
318 4211 : int CPL_STDCALL GDALFlushCacheBlock()
319 :
320 : {
321 4211 : return GDALRasterBlock::FlushCacheBlock();
322 : }
323 :
324 : /************************************************************************/
325 : /* ==================================================================== */
326 : /* GDALRasterBlock */
327 : /* ==================================================================== */
328 : /************************************************************************/
329 :
330 : /**
331 : * \class GDALRasterBlock "gdal_priv.h"
332 : *
333 : * GDALRasterBlock objects hold one block of raster data for one band
334 : * that is currently stored in the GDAL raster cache. The cache holds
335 : * some blocks of raster data for zero or more GDALRasterBand objects
336 : * across zero or more GDALDataset objects in a global raster cache with
337 : * a least recently used (LRU) list and an upper cache limit (see
338 : * GDALSetCacheMax()) under which the cache size is normally kept.
339 : *
340 : * Some blocks in the cache may be modified relative to the state on disk
341 : * (they are marked "Dirty") and must be flushed to disk before they can
342 : * be discarded. Other (Clean) blocks may just be discarded if their memory
343 : * needs to be recovered.
344 : *
345 : * In normal situations applications do not interact directly with the
346 : * GDALRasterBlock - instead it it utilized by the RasterIO() interfaces
347 : * to implement caching.
348 : *
349 : * Some driver classes are implemented in a fashion that completely avoids
350 : * use of the GDAL raster cache (and GDALRasterBlock) though this is not very
351 : * common.
352 : */
353 :
354 : /************************************************************************/
355 : /* FlushCacheBlock() */
356 : /* */
357 : /* Note, if we have a lot of blocks locked for a long time, this */
358 : /* method is going to get slow because it will have to traverse */
359 : /* the linked list a long ways looking for a flushing */
360 : /* candidate. It might help to re-touch locked blocks to push */
361 : /* them to the top of the list. */
362 : /************************************************************************/
363 :
364 : /**
365 : * \brief Attempt to flush at least one block from the cache.
366 : *
367 : * This static method is normally used to recover memory when a request
368 : * for a new cache block would put cache memory use over the established
369 : * limit.
370 : *
371 : * C++ analog to the C function GDALFlushCacheBlock().
372 : *
373 : * @param bDirtyBlocksOnly Only flushes dirty blocks.
374 : * @return TRUE if successful or FALSE if no flushable block is found.
375 : */
376 :
377 4216 : int GDALRasterBlock::FlushCacheBlock(int bDirtyBlocksOnly)
378 :
379 : {
380 : GDALRasterBlock *poTarget;
381 :
382 : {
383 4216 : INITIALIZE_LOCK;
384 4216 : poTarget = poOldest;
385 :
386 4226 : while (poTarget != nullptr)
387 : {
388 4229 : if (!bDirtyBlocksOnly ||
389 9 : (poTarget->GetDirty() && nDisableDirtyBlockFlushCounter == 0))
390 : {
391 4211 : if (CPLAtomicCompareAndExchange(&(poTarget->nLockCount), 0, -1))
392 4210 : break;
393 : }
394 10 : poTarget = poTarget->poPrevious;
395 : }
396 :
397 4216 : if (poTarget == nullptr)
398 6 : return FALSE;
399 : #ifndef __COVERITY__
400 : // Disabled to avoid complains about sleeping under locks, that
401 : // are only true for debug/testing code
402 4210 : if (bSleepsForBockCacheDebug)
403 : {
404 6 : const double dfDelay = CPLAtof(CPLGetConfigOption(
405 : "GDAL_RB_FLUSHBLOCK_SLEEP_AFTER_DROP_LOCK", "0"));
406 6 : if (dfDelay > 0)
407 3 : CPLSleep(dfDelay);
408 : }
409 : #endif
410 :
411 4210 : poTarget->Detach_unlocked();
412 4210 : poTarget->GetBand()->UnreferenceBlock(poTarget);
413 : }
414 :
415 : #ifndef __COVERITY__
416 : // Disabled to avoid complains about sleeping under locks, that
417 : // are only true for debug/testing code
418 4210 : if (bSleepsForBockCacheDebug)
419 : {
420 6 : const double dfDelay = CPLAtof(
421 : CPLGetConfigOption("GDAL_RB_FLUSHBLOCK_SLEEP_AFTER_RB_LOCK", "0"));
422 6 : if (dfDelay > 0)
423 1 : CPLSleep(dfDelay);
424 : }
425 : #endif
426 :
427 4210 : if (poTarget->GetDirty())
428 : {
429 30 : const CPLErr eErr = poTarget->Write();
430 30 : if (eErr != CE_None)
431 : {
432 : // Save the error for later reporting.
433 0 : poTarget->GetBand()->SetFlushBlockErr(eErr);
434 : }
435 : }
436 :
437 4210 : VSIFreeAligned(poTarget->pData);
438 4210 : poTarget->pData = nullptr;
439 4210 : poTarget->GetBand()->AddBlockToFreeList(poTarget);
440 :
441 4210 : return TRUE;
442 : }
443 :
444 : /************************************************************************/
445 : /* FlushDirtyBlocks() */
446 : /************************************************************************/
447 :
448 : /**
449 : * \brief Flush all dirty blocks from cache.
450 : *
451 : * This static method is normally used to recover memory and is especially
452 : * useful when doing multi-threaded code that can trigger the block cache.
453 : *
454 : * Due to the current design of the block cache, dirty blocks belonging to a
455 : * same dataset could be pushed simultaneously to the IWriteBlock() method of
456 : * that dataset from different threads, causing races.
457 : *
458 : * Calling this method before that code can help to work around that issue,
459 : * in a multiple readers, one writer scenario.
460 : *
461 : * @since GDAL 2.0
462 : */
463 :
464 5 : void GDALRasterBlock::FlushDirtyBlocks()
465 :
466 : {
467 5 : while (FlushCacheBlock(TRUE))
468 : {
469 : /* go on */
470 : }
471 5 : }
472 :
473 : /************************************************************************/
474 : /* EnterDisableDirtyBlockFlush() */
475 : /************************************************************************/
476 :
477 : /**
478 : * \brief Starts preventing dirty blocks from being flushed
479 : *
480 : * This static method is used to prevent dirty blocks from being flushed.
481 : * This might be useful when in a IWriteBlock() method, whose implementation
482 : * can directly/indirectly cause the block cache to evict new blocks, to
483 : * be recursively called on the same dataset.
484 : *
485 : * This method implements a reference counter and is thread-safe.
486 : *
487 : * This call must be paired with a corresponding LeaveDisableDirtyBlockFlush().
488 : *
489 : * @since GDAL 2.2.2
490 : */
491 :
492 14109 : void GDALRasterBlock::EnterDisableDirtyBlockFlush()
493 : {
494 14109 : CPLAtomicInc(&nDisableDirtyBlockFlushCounter);
495 14109 : }
496 :
497 : /************************************************************************/
498 : /* LeaveDisableDirtyBlockFlush() */
499 : /************************************************************************/
500 :
501 : /**
502 : * \brief Ends preventing dirty blocks from being flushed.
503 : *
504 : * Undoes the effect of EnterDisableDirtyBlockFlush().
505 : *
506 : * @since GDAL 2.2.2
507 : */
508 :
509 14109 : void GDALRasterBlock::LeaveDisableDirtyBlockFlush()
510 : {
511 14109 : CPLAtomicDec(&nDisableDirtyBlockFlushCounter);
512 14109 : }
513 :
514 : /************************************************************************/
515 : /* GDALRasterBlock() */
516 : /************************************************************************/
517 :
518 : /**
519 : * @brief GDALRasterBlock Constructor
520 : *
521 : * Normally only called from GDALRasterBand::GetLockedBlockRef().
522 : *
523 : * @param poBandIn the raster band used as source of raster block
524 : * being constructed.
525 : *
526 : * @param nXOffIn the horizontal block offset, with zero indicating
527 : * the left most block, 1 the next block and so forth.
528 : *
529 : * @param nYOffIn the vertical block offset, with zero indicating
530 : * the top most block, 1 the next block and so forth.
531 : */
532 :
533 3355840 : GDALRasterBlock::GDALRasterBlock(GDALRasterBand *poBandIn, int nXOffIn,
534 3355840 : int nYOffIn)
535 3355840 : : eType(poBandIn->GetRasterDataType()), nXOff(nXOffIn), nYOff(nYOffIn),
536 3355820 : poBand(poBandIn), bMustDetach(true)
537 : {
538 3355820 : if (!hRBLock)
539 : {
540 : // Needed for scenarios where GDALAllRegister() is called after
541 : // GDALDestroyDriverManager()
542 290 : INITIALIZE_LOCK;
543 : }
544 :
545 3355820 : CPLAssert(poBandIn != nullptr);
546 3355820 : poBand->GetBlockSize(&nXSize, &nYSize);
547 3355820 : }
548 :
549 : /************************************************************************/
550 : /* GDALRasterBlock() */
551 : /************************************************************************/
552 :
553 : /**
554 : * @brief GDALRasterBlock Constructor (for GDALHashSetBandBlockAccess purpose)
555 : *
556 : * Normally only called from GDALHashSetBandBlockAccess class. Such a block
557 : * is completely non functional and only meant as being used to do a look-up
558 : * in the hash set of GDALHashSetBandBlockAccess
559 : *
560 : * @param nXOffIn the horizontal block offset, with zero indicating
561 : * the left most block, 1 the next block and so forth.
562 : *
563 : * @param nYOffIn the vertical block offset, with zero indicating
564 : * the top most block, 1 the next block and so forth.
565 : */
566 :
567 2960300 : GDALRasterBlock::GDALRasterBlock(int nXOffIn, int nYOffIn)
568 2960300 : : nXOff(nXOffIn), nYOff(nYOffIn)
569 : {
570 2960300 : }
571 :
572 : /************************************************************************/
573 : /* RecycleFor() */
574 : /************************************************************************/
575 :
576 : /**
577 : * Recycle an existing block (of the same band)
578 : *
579 : * Normally called from GDALAbstractBandBlockCache::CreateBlock().
580 : */
581 :
582 10890 : void GDALRasterBlock::RecycleFor(int nXOffIn, int nYOffIn)
583 : {
584 10890 : CPLAssert(pData == nullptr);
585 10890 : pData = nullptr;
586 10890 : bDirty = false;
587 10890 : nLockCount = 0;
588 :
589 10890 : poNext = nullptr;
590 10890 : poPrevious = nullptr;
591 :
592 10890 : nXOff = nXOffIn;
593 10890 : nYOff = nYOffIn;
594 10890 : bMustDetach = true;
595 10890 : }
596 :
597 : /************************************************************************/
598 : /* ~GDALRasterBlock() */
599 : /************************************************************************/
600 :
601 : /**
602 : * Block destructor.
603 : *
604 : * Normally called from GDALRasterBand::FlushBlock().
605 : */
606 :
607 12632300 : GDALRasterBlock::~GDALRasterBlock()
608 :
609 : {
610 6316140 : Detach();
611 :
612 6316130 : if (pData != nullptr)
613 : {
614 3336900 : VSIFreeAligned(pData);
615 : }
616 :
617 6316140 : CPLAssert(nLockCount <= 0);
618 :
619 : #ifdef ENABLE_DEBUG
620 : Verify();
621 : #endif
622 6316140 : }
623 :
624 : /************************************************************************/
625 : /* GetEffectiveBlockSize() */
626 : /************************************************************************/
627 :
628 6733470 : static size_t GetEffectiveBlockSize(GPtrDiff_t nBlockSize)
629 : {
630 : // The real cost of a block allocation is more than just nBlockSize
631 : // As we allocate with 64-byte alignment, use 64 as a multiple.
632 : // We arbitrarily add 2 * sizeof(GDALRasterBlock) to account for that
633 : return static_cast<size_t>(
634 13466900 : std::min(static_cast<GUIntBig>(UINT_MAX),
635 6733470 : static_cast<GUIntBig>(DIV_ROUND_UP(nBlockSize, 64)) * 64 +
636 6733470 : 2 * sizeof(GDALRasterBlock)));
637 : }
638 :
639 : /************************************************************************/
640 : /* Detach() */
641 : /************************************************************************/
642 :
643 : /**
644 : * Remove block from cache.
645 : *
646 : * This method removes the current block from the linked list used to keep
647 : * track of all cached blocks in order of age. It does not affect whether
648 : * the block is referenced by a GDALRasterBand nor does it destroy or flush
649 : * the block.
650 : */
651 :
652 7636950 : void GDALRasterBlock::Detach()
653 :
654 : {
655 7636950 : if (bMustDetach)
656 : {
657 6673810 : TAKE_LOCK;
658 3336910 : Detach_unlocked();
659 : }
660 7636950 : }
661 :
662 3366740 : void GDALRasterBlock::Detach_unlocked()
663 : {
664 3366740 : if (poOldest == this)
665 2782580 : poOldest = poPrevious;
666 :
667 3366740 : if (poNewest == this)
668 : {
669 28482 : poNewest = poNext;
670 : }
671 :
672 3366740 : if (poPrevious != nullptr)
673 3338250 : poPrevious->poNext = poNext;
674 :
675 3366740 : if (poNext != nullptr)
676 584152 : poNext->poPrevious = poPrevious;
677 :
678 3366740 : poPrevious = nullptr;
679 3366740 : poNext = nullptr;
680 3366740 : bMustDetach = false;
681 :
682 3366740 : if (pData)
683 3366740 : nCacheUsed -= GetEffectiveBlockSize(GetBlockSize());
684 :
685 : #ifdef ENABLE_DEBUG
686 : Verify();
687 : #endif
688 3366740 : }
689 :
690 : /************************************************************************/
691 : /* Verify() */
692 : /************************************************************************/
693 :
694 : /**
695 : * Confirms (via assertions) that the block cache linked list is in a
696 : * consistent state.
697 : */
698 :
699 : #ifdef ENABLE_DEBUG
700 : void GDALRasterBlock::Verify()
701 :
702 : {
703 : TAKE_LOCK;
704 :
705 : CPLAssert((poNewest == nullptr && poOldest == nullptr) ||
706 : (poNewest != nullptr && poOldest != nullptr));
707 :
708 : if (poNewest != nullptr)
709 : {
710 : CPLAssert(poNewest->poPrevious == nullptr);
711 : CPLAssert(poOldest->poNext == nullptr);
712 :
713 : GDALRasterBlock *poLast = nullptr;
714 : for (GDALRasterBlock *poBlock = poNewest; poBlock != nullptr;
715 : poBlock = poBlock->poNext)
716 : {
717 : CPLAssert(poBlock->poPrevious == poLast);
718 :
719 : poLast = poBlock;
720 : }
721 :
722 : CPLAssert(poOldest == poLast);
723 : }
724 : }
725 :
726 : #else
727 0 : void GDALRasterBlock::Verify()
728 : {
729 0 : }
730 : #endif
731 :
732 : #ifdef notdef
733 : void GDALRasterBlock::CheckNonOrphanedBlocks(GDALRasterBand *poBand)
734 : {
735 : TAKE_LOCK;
736 : for (GDALRasterBlock *poBlock = poNewest; poBlock != nullptr;
737 : poBlock = poBlock->poNext)
738 : {
739 : if (poBlock->GetBand() == poBand)
740 : {
741 : printf("Cache has still blocks of band %p\n", poBand); /*ok*/
742 : printf("Band : %d\n", poBand->GetBand()); /*ok*/
743 : printf("nRasterXSize = %d\n", poBand->GetXSize()); /*ok*/
744 : printf("nRasterYSize = %d\n", poBand->GetYSize()); /*ok*/
745 : int nBlockXSize, nBlockYSize;
746 : poBand->GetBlockSize(&nBlockXSize, &nBlockYSize);
747 : printf("nBlockXSize = %d\n", nBlockXSize); /*ok*/
748 : printf("nBlockYSize = %d\n", nBlockYSize); /*ok*/
749 : printf("Dataset : %p\n", poBand->GetDataset()); /*ok*/
750 : if (poBand->GetDataset())
751 : printf("Dataset : %s\n", /*ok*/
752 : poBand->GetDataset()->GetDescription());
753 : }
754 : }
755 : }
756 : #endif
757 :
758 : /************************************************************************/
759 : /* Write() */
760 : /************************************************************************/
761 :
762 : /**
763 : * Force writing of the current block, if dirty.
764 : *
765 : * The block is written using GDALRasterBand::IWriteBlock() on its
766 : * corresponding band object. Even if the write fails the block will
767 : * be marked clean.
768 : *
769 : * @return CE_None otherwise the error returned by IWriteBlock().
770 : */
771 :
772 227801 : CPLErr GDALRasterBlock::Write()
773 :
774 : {
775 227801 : if (!GetDirty())
776 0 : return CE_None;
777 :
778 227801 : if (poBand == nullptr)
779 0 : return CE_Failure;
780 :
781 227801 : MarkClean();
782 :
783 227800 : if (poBand->eFlushBlockErr == CE_None)
784 : {
785 227800 : int bCallLeaveReadWrite = poBand->EnterReadWrite(GF_Write);
786 227800 : CPLErr eErr = poBand->IWriteBlock(nXOff, nYOff, pData);
787 227801 : if (bCallLeaveReadWrite)
788 125376 : poBand->LeaveReadWrite();
789 227799 : return eErr;
790 : }
791 : else
792 0 : return poBand->eFlushBlockErr;
793 : }
794 :
795 : /************************************************************************/
796 : /* Touch() */
797 : /************************************************************************/
798 :
799 : /**
800 : * Push block to top of LRU (least-recently used) list.
801 : *
802 : * This method is normally called when a block is used to keep track
803 : * that it has been recently used.
804 : */
805 :
806 7143760 : void GDALRasterBlock::Touch()
807 :
808 : {
809 : // Can be safely tested outside the lock
810 7143760 : if (poNewest == this)
811 333413 : return;
812 :
813 13620800 : TAKE_LOCK;
814 6810470 : Touch_unlocked();
815 : }
816 :
817 10177200 : void GDALRasterBlock::Touch_unlocked()
818 :
819 : {
820 : // Could happen even if tested in Touch() before taking the lock
821 : // Scenario would be :
822 : // 0. this is the second block (the one pointed by poNewest->poNext)
823 : // 1. Thread 1 calls Touch() and poNewest != this at that point
824 : // 2. Thread 2 detaches poNewest
825 : // 3. Thread 1 arrives here
826 10177200 : if (poNewest == this)
827 0 : return;
828 :
829 : // We should not try to touch a block that has been detached.
830 : // If that happen, corruption has already occurred.
831 10177200 : CPLAssert(bMustDetach);
832 :
833 10177200 : if (poOldest == this)
834 1548100 : poOldest = this->poPrevious;
835 :
836 10177200 : if (poPrevious != nullptr)
837 6810470 : poPrevious->poNext = poNext;
838 :
839 10177200 : if (poNext != nullptr)
840 5262380 : poNext->poPrevious = poPrevious;
841 :
842 10177200 : poPrevious = nullptr;
843 10177200 : poNext = poNewest;
844 :
845 10177200 : if (poNewest != nullptr)
846 : {
847 10154600 : CPLAssert(poNewest->poPrevious == nullptr);
848 10154600 : poNewest->poPrevious = this;
849 : }
850 10177200 : poNewest = this;
851 :
852 10177200 : if (poOldest == nullptr)
853 : {
854 22595 : CPLAssert(poPrevious == nullptr && poNext == nullptr);
855 22595 : poOldest = this;
856 : }
857 : #ifdef ENABLE_DEBUG
858 : Verify();
859 : #endif
860 : }
861 :
862 : /************************************************************************/
863 : /* Internalize() */
864 : /************************************************************************/
865 :
866 : /**
867 : * Allocate memory for block.
868 : *
869 : * This method allocates memory for the block, and attempts to flush other
870 : * blocks, if necessary, to bring the total cache size back within the limits.
871 : * The newly allocated block is touched and will be considered most recently
872 : * used in the LRU list.
873 : *
874 : * @return CE_None on success or CE_Failure if memory allocation fails.
875 : */
876 :
877 3366720 : CPLErr GDALRasterBlock::Internalize()
878 :
879 : {
880 3366720 : CPLAssert(pData == nullptr);
881 :
882 3366720 : void *pNewData = nullptr;
883 :
884 : // This call will initialize the hRBLock mutex. Other call places can
885 : // only be called if we have go through there.
886 3366720 : const GIntBig nCurCacheMax = GDALGetCacheMax64();
887 :
888 : // No risk of overflow as it is checked in GDALRasterBand::InitBlockInfo().
889 3366720 : const auto nSizeInBytes = GetBlockSize();
890 :
891 : /* -------------------------------------------------------------------- */
892 : /* Flush old blocks if we are nearing our memory limit. */
893 : /* -------------------------------------------------------------------- */
894 3366700 : bool bFirstIter = true;
895 3366700 : bool bLoopAgain = false;
896 3366700 : GDALDataset *poThisDS = poBand->GetDataset();
897 3366770 : do
898 : {
899 3366740 : bLoopAgain = false;
900 3366740 : GDALRasterBlock *apoBlocksToFree[64] = {nullptr};
901 3366740 : int nBlocksToFree = 0;
902 : {
903 6733500 : TAKE_LOCK;
904 :
905 3366770 : if (bFirstIter)
906 3366740 : nCacheUsed += GetEffectiveBlockSize(nSizeInBytes);
907 3366770 : GDALRasterBlock *poTarget = poOldest;
908 3385260 : while (nCacheUsed > nCurCacheMax)
909 : {
910 36276 : GDALRasterBlock *poDirtyBlockOtherDataset = nullptr;
911 : // In this first pass, only discard dirty blocks of this
912 : // dataset. We do this to decrease significantly the likelihood
913 : // of the following weakness of the block cache design:
914 : // 1. Thread 1 fills block B with ones
915 : // 2. Thread 2 evicts this dirty block, while thread 1 almost
916 : // at the same time (but slightly after) tries to reacquire
917 : // this block. As it has been removed from the block cache
918 : // array/set, thread 1 now tries to read block B from disk,
919 : // so gets the old value.
920 166347 : while (poTarget != nullptr)
921 : {
922 155684 : if (!poTarget->GetDirty())
923 : {
924 25268 : if (CPLAtomicCompareAndExchange(&(poTarget->nLockCount),
925 25268 : 0, -1))
926 18487 : break;
927 : }
928 130416 : else if (nDisableDirtyBlockFlushCounter == 0)
929 : {
930 130416 : if (poTarget->poBand->GetDataset() == poThisDS)
931 : {
932 7126 : if (CPLAtomicCompareAndExchange(
933 7126 : &(poTarget->nLockCount), 0, -1))
934 7126 : break;
935 : }
936 123290 : else if (poDirtyBlockOtherDataset == nullptr)
937 : {
938 7923 : poDirtyBlockOtherDataset = poTarget;
939 : }
940 : }
941 130071 : poTarget = poTarget->poPrevious;
942 : }
943 36276 : if (poTarget == nullptr && poDirtyBlockOtherDataset)
944 : {
945 6 : if (CPLAtomicCompareAndExchange(
946 6 : &(poDirtyBlockOtherDataset->nLockCount), 0, -1))
947 : {
948 6 : CPLDebug("GDAL",
949 : "Evicting dirty block of another dataset");
950 6 : poTarget = poDirtyBlockOtherDataset;
951 : }
952 : else
953 : {
954 0 : poTarget = poOldest;
955 0 : while (poTarget != nullptr)
956 : {
957 0 : if (CPLAtomicCompareAndExchange(
958 0 : &(poTarget->nLockCount), 0, -1))
959 : {
960 0 : CPLDebug(
961 : "GDAL",
962 : "Evicting dirty block of another dataset");
963 0 : break;
964 : }
965 0 : poTarget = poTarget->poPrevious;
966 : }
967 : }
968 : }
969 :
970 36276 : if (poTarget != nullptr)
971 : {
972 : #ifndef __COVERITY__
973 : // Disabled to avoid complains about sleeping under locks,
974 : // that are only true for debug/testing code
975 25619 : if (bSleepsForBockCacheDebug)
976 : {
977 2 : const double dfDelay = CPLAtof(CPLGetConfigOption(
978 : "GDAL_RB_INTERNALIZE_SLEEP_AFTER_DROP_LOCK", "0"));
979 2 : if (dfDelay > 0)
980 1 : CPLSleep(dfDelay);
981 : }
982 : #endif
983 :
984 25619 : GDALRasterBlock *_poPrevious = poTarget->poPrevious;
985 :
986 25619 : poTarget->Detach_unlocked();
987 25619 : poTarget->GetBand()->UnreferenceBlock(poTarget);
988 :
989 25619 : apoBlocksToFree[nBlocksToFree++] = poTarget;
990 25619 : if (poTarget->GetDirty())
991 : {
992 : // Only free one dirty block at a time so that
993 : // other dirty blocks of other bands with the same
994 : // coordinates can be found with TryGetLockedBlock()
995 7132 : bLoopAgain = nCacheUsed > nCurCacheMax;
996 7132 : break;
997 : }
998 18487 : if (nBlocksToFree == 64)
999 : {
1000 0 : bLoopAgain = (nCacheUsed > nCurCacheMax);
1001 0 : break;
1002 : }
1003 :
1004 18487 : poTarget = _poPrevious;
1005 : }
1006 : else
1007 : {
1008 10657 : break;
1009 : }
1010 : }
1011 :
1012 : /* ------------------------------------------------------------------
1013 : */
1014 : /* Add this block to the list. */
1015 : /* ------------------------------------------------------------------
1016 : */
1017 3366770 : if (!bLoopAgain)
1018 3366740 : Touch_unlocked();
1019 : }
1020 :
1021 3366770 : bFirstIter = false;
1022 :
1023 : // Now free blocks we have detached and removed from their band.
1024 3392390 : for (int i = 0; i < nBlocksToFree; ++i)
1025 : {
1026 25619 : GDALRasterBlock *const poBlock = apoBlocksToFree[i];
1027 :
1028 25619 : if (poBlock->GetDirty())
1029 : {
1030 : #ifndef __COVERITY__
1031 : // Disabled to avoid complains about sleeping under locks, that
1032 : // are only true for debug/testing code
1033 7132 : if (bSleepsForBockCacheDebug)
1034 : {
1035 1 : const double dfDelay = CPLAtof(CPLGetConfigOption(
1036 : "GDAL_RB_INTERNALIZE_SLEEP_AFTER_DETACH_BEFORE_WRITE",
1037 : "0"));
1038 1 : if (dfDelay > 0)
1039 1 : CPLSleep(dfDelay);
1040 : }
1041 : #endif
1042 :
1043 7132 : CPLErr eErr = poBlock->Write();
1044 7132 : if (eErr != CE_None)
1045 : {
1046 : // Save the error for later reporting.
1047 0 : poBlock->GetBand()->SetFlushBlockErr(eErr);
1048 : }
1049 : }
1050 :
1051 : // Try to recycle the data of an existing block.
1052 25619 : void *pDataBlock = poBlock->pData;
1053 50702 : if (pNewData == nullptr && pDataBlock != nullptr &&
1054 25083 : poBlock->GetBlockSize() == nSizeInBytes)
1055 : {
1056 24981 : pNewData = pDataBlock;
1057 : }
1058 : else
1059 : {
1060 638 : VSIFreeAligned(poBlock->pData);
1061 : }
1062 25619 : poBlock->pData = nullptr;
1063 :
1064 25619 : poBlock->GetBand()->AddBlockToFreeList(poBlock);
1065 : }
1066 : } while (bLoopAgain);
1067 :
1068 3366740 : if (pNewData == nullptr)
1069 : {
1070 3341750 : pNewData = VSI_MALLOC_ALIGNED_AUTO_VERBOSE(nSizeInBytes);
1071 3341740 : if (pNewData == nullptr)
1072 : {
1073 0 : return (CE_Failure);
1074 : }
1075 : }
1076 :
1077 3366720 : pData = pNewData;
1078 :
1079 3366720 : return CE_None;
1080 : }
1081 :
1082 : /************************************************************************/
1083 : /* MarkDirty() */
1084 : /************************************************************************/
1085 :
1086 : /**
1087 : * Mark the block as modified.
1088 : *
1089 : * A dirty block is one that has been modified and will need to be written
1090 : * to disk before it can be flushed.
1091 : */
1092 :
1093 3977220 : void GDALRasterBlock::MarkDirty()
1094 : {
1095 3977220 : if (poBand)
1096 : {
1097 3977220 : poBand->InitRWLock();
1098 3977220 : if (!bDirty)
1099 398393 : poBand->IncDirtyBlocks(1);
1100 : }
1101 3977220 : bDirty = true;
1102 3977220 : }
1103 :
1104 : /************************************************************************/
1105 : /* MarkClean() */
1106 : /************************************************************************/
1107 :
1108 : /**
1109 : * Mark the block as unmodified.
1110 : *
1111 : * A dirty block is one that has been modified and will need to be written
1112 : * to disk before it can be flushed.
1113 : */
1114 :
1115 396287 : void GDALRasterBlock::MarkClean()
1116 : {
1117 396287 : if (bDirty && poBand)
1118 396257 : poBand->IncDirtyBlocks(-1);
1119 396286 : bDirty = false;
1120 396286 : }
1121 :
1122 : /************************************************************************/
1123 : /* DestroyRBMutex() */
1124 : /************************************************************************/
1125 :
1126 : /*! @cond Doxygen_Suppress */
1127 1121 : void GDALRasterBlock::DestroyRBMutex()
1128 : {
1129 1121 : if (hRBLock != nullptr)
1130 378 : DESTROY_LOCK;
1131 1121 : hRBLock = nullptr;
1132 1121 : }
1133 :
1134 : /*! @endcond */
1135 :
1136 : /************************************************************************/
1137 : /* TakeLock() */
1138 : /************************************************************************/
1139 :
1140 : /**
1141 : * Take a lock and Touch().
1142 : *
1143 : * Should only be used by GDALArrayBandBlockCache::TryGetLockedBlockRef()
1144 : * and GDALHashSetBandBlockCache::TryGetLockedBlockRef()
1145 : *
1146 : * @return TRUE if the lock has been successfully acquired. If FALSE, the
1147 : * block is being evicted by another thread, and so should be
1148 : * considered as invalid.
1149 : */
1150 :
1151 7143700 : int GDALRasterBlock::TakeLock()
1152 : {
1153 7143700 : const int nLockVal = AddLock();
1154 7143750 : CPLAssert(nLockVal >= 0);
1155 : #ifndef __COVERITY__
1156 : // Disabled to avoid complains about sleeping under locks, that
1157 : // are only true for debug/testing code
1158 7143750 : if (bSleepsForBockCacheDebug)
1159 : {
1160 4 : const double dfDelay = CPLAtof(
1161 : CPLGetConfigOption("GDAL_RB_TRYGET_SLEEP_AFTER_TAKE_LOCK", "0"));
1162 4 : if (dfDelay > 0)
1163 1 : CPLSleep(dfDelay);
1164 : }
1165 : #endif
1166 :
1167 7143730 : if (nLockVal == 0)
1168 : {
1169 : // The block is being evicted by GDALRasterBlock::Internalize()
1170 : // or FlushCacheBlock()
1171 :
1172 : #ifdef DEBUG
1173 4 : CPLDebug(
1174 : "GDAL",
1175 : "TakeLock(%p): Block(%d,%d,%p) is being evicted while trying to "
1176 : "reacquire it.",
1177 2 : reinterpret_cast<void *>(CPLGetPID()), nXOff, nYOff, poBand);
1178 : #endif
1179 2 : DropLock();
1180 :
1181 2 : return FALSE;
1182 : }
1183 7143730 : Touch();
1184 7143880 : return TRUE;
1185 : }
1186 :
1187 : /************************************************************************/
1188 : /* DropLockForRemovalFromStorage() */
1189 : /************************************************************************/
1190 :
1191 : /**
1192 : * Drop a lock before removing the block from the band storage.
1193 : *
1194 : * Should only be used by GDALArrayBandBlockCache::FlushBlock()
1195 : * and GDALHashSetBandBlockCache::FlushBlock()
1196 : *
1197 : * @return TRUE if the lock has been successfully dropped.
1198 : */
1199 :
1200 3336910 : int GDALRasterBlock::DropLockForRemovalFromStorage()
1201 : {
1202 : // Detect potential conflict with GDALRasterBlock::Internalize()
1203 : // or FlushCacheBlock()
1204 3336910 : if (CPLAtomicCompareAndExchange(&nLockCount, 0, -1))
1205 3336900 : return TRUE;
1206 : #ifdef DEBUG
1207 4 : CPLDebug("GDAL",
1208 : "DropLockForRemovalFromStorage(%p): Block(%d,%d,%p) was attempted "
1209 : "to be flushed from band but it is flushed by global cache.",
1210 2 : reinterpret_cast<void *>(CPLGetPID()), nXOff, nYOff, poBand);
1211 : #endif
1212 :
1213 : // Wait for the block for having been unreferenced.
1214 2 : TAKE_LOCK;
1215 :
1216 2 : return FALSE;
1217 : }
1218 :
1219 : #if 0
1220 : void GDALRasterBlock::DumpAll()
1221 : {
1222 : int iBlock = 0;
1223 : for( GDALRasterBlock *poBlock = poNewest;
1224 : poBlock != nullptr;
1225 : poBlock = poBlock->poNext )
1226 : {
1227 : printf("Block %d\n", iBlock);/*ok*/
1228 : poBlock->DumpBlock();
1229 : printf("\n");/*ok*/
1230 : iBlock++;
1231 : }
1232 : }
1233 :
1234 : void GDALRasterBlock::DumpBlock()
1235 : {
1236 : printf(" Lock count = %d\n", nLockCount);/*ok*/
1237 : printf(" bDirty = %d\n", static_cast<int>(bDirty));/*ok*/
1238 : printf(" nXOff = %d\n", nXOff);/*ok*/
1239 : printf(" nYOff = %d\n", nYOff);/*ok*/
1240 : printf(" nXSize = %d\n", nXSize);/*ok*/
1241 : printf(" nYSize = %d\n", nYSize);/*ok*/
1242 : printf(" eType = %d\n", eType);/*ok*/
1243 : printf(" Band %p\n", GetBand());/*ok*/
1244 : printf(" Band %d\n", GetBand()->GetBand());/*ok*/
1245 : if( GetBand()->GetDataset() )
1246 : printf(" Dataset = %s\n",/*ok*/
1247 : GetBand()->GetDataset()->GetDescription());
1248 : }
1249 : #endif // if 0
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