common/SC_AllocPool.cpp

   1 /*
   2         SuperCollider real time audio synthesis system
   3     Copyright (c) 2002 James McCartney. All rights reserved.
   4         http://www.audiosynth.com
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  19 */
  20
  21 #include <string.h>
  22 #include <stdexcept>
  23 #include "SC_AllocPool.h"
  24 #include "SC_BoundsMacros.h"
  25 #include <assert.h>
  26 #include <string>
  27
  28 /*
  29    Requests are `small' if both the corresponding and the next bin are small
  30 */
  31
  32 #if DEBUG
  33 #define check_pool()  DoCheckPool()
  34 #define check_free_chunk(P)  DoCheckFreeChunk(P)
  35 #define check_inuse_chunk(P) DoCheckInUseChunk(P)
  36 #define check_chunk(P) DoCheckChunk(P)
  37 #define check_malloced_chunk(P,N) DoCheckAllocedChunk(P,N)
  38 #define garbage_fill(P) DoGarbageFill(P)
  39 #else
  40 #define check_pool()
  41 #define check_free_chunk(P)
  42 #define check_inuse_chunk(P)
  43 #define check_chunk(P)
  44 #define check_malloced_chunk(P,N)
  45 #define garbage_fill(P)
  46 #endif
  47
  48 #define aligned_OK(m)    ((((size_t)(m)) & kAlignMask) == 0)
  49
  50 /*
  51 void* allocmem(AllocPool *pool, int32 size);
  52 void* allocmem(AllocPool *pool, int32 size)
  53 {
  54         return pool->Alloc(size);
  55 }
  56
  57 void* reallocmem(AllocPool *pool, void* ptr, int32 size);
  58 void* reallocmem(AllocPool *pool, void* ptr, int32 size)
  59 {
  60         return pool->Realloc(ptr, size);
  61 }
  62
  63 void freemem(AllocPool *pool, void* ptr);
  64 void freemem(AllocPool *pool, void* ptr)
  65 {
  66         pool->Free(ptr);
  67 }
  68 */
  69 void AllocPool::InitAlloc()
  70 {
  71         if (mAreaInitSize == 0) return;
  72
  73         /* alloc initial area */
  74         NewArea(mAreaInitSize);
  75         /* get chunk */
  76         AllocAreaPtr area = mAreas;
  77         AllocChunkPtr chunk = &area->mChunk;
  78         LinkFree(chunk);
  79
  80         check_pool();
  81 }
  82
  83 void AllocPool::InitBins()
  84 {
  85         for (int i=0; i<kNumAllocBins; ++i) {
  86                 mBins[i].BeEmpty();
  87         }
  88         for (int i=0; i<4; ++i) {
  89                 mBinBlocks[i] = 0;
  90         }
  91 }
  92
  93 AllocPool::AllocPool(NewAreaFunc inAllocArea, FreeAreaFunc inFreeArea,
  94                                         size_t inAreaInitSize, size_t inAreaMoreSize)
  95 {
  96         InitBins();
  97         mAreaInitSize = inAreaInitSize;
  98         mAreaMoreSize = inAreaMoreSize;
  99         mAllocArea = inAllocArea;
 100         mFreeArea = inFreeArea;
 101         mAreas = 0;
 102         check_pool();
 103
 104         InitAlloc();
 105 }
 106
 107 AllocPool::~AllocPool()
 108 {
 109         FreeAll();
 110 }
 111
 112 void AllocPool::FreeAll()
 113 {
 114         check_pool();
 115         AllocAreaPtr area = mAreas;
 116         if (area) {
 117                 AllocAreaPtr firstArea = area;
 118                 do {
 119                         AllocAreaPtr nextarea = area->mNext;
 120                         (mFreeArea)(area->mUnalignedPointerToThis);
 121                         area = nextarea;
 122                 } while (area != firstArea);
 123                 mAreas = NULL;
 124         }
 125         InitBins();
 126         check_pool();
 127 }
 128
 129 void AllocPool::FreeAllInternal()
 130 {
 131         check_pool();
 132         InitBins();
 133
 134         AllocAreaPtr area = mAreas;
 135         if (area) {
 136                 AllocAreaPtr firstArea = area;
 137                 do {
 138                         AllocAreaPtr nextarea = area->mNext;
 139                         size_t size = area->mSize;
 140                 AllocChunkPtr chunk = &area->mChunk;
 141                         chunk->SetSizeFree(size);
 142                         chunk->SetNeighborsInUse(size);
 143                         LinkFree(chunk);
 144                         area = nextarea;
 145                 } while (area != firstArea);
 146         }
 147         check_pool();
 148 }
 149
 150 void AllocPool::Reinit()
 151 {
 152         FreeAll();
 153         InitAlloc();
 154 }
 155
 156 void AllocPool::Free(void *inPtr)
 157 {
 158 #ifdef DISABLE_MEMORY_POOLS
 159         free(inPtr);
 160         return;
 161 #endif
 162
 163         check_pool();
 164         if (inPtr == 0) return;                   /* free(0) has no effect */
 165
 166         AllocChunkPtr chunk = MemToChunk(inPtr);
 167
 168         check_inuse_chunk(chunk);
 169         garbage_fill(chunk);
 170
 171         size_t size = chunk->Size();
 172
 173         if (!chunk->PrevInUse()) /* consolidate backward */
 174         {
 175                 size_t prevSize = chunk->PrevSize();
 176                 chunk = chunk->ChunkAtOffset(0L-prevSize);
 177                 size += prevSize;
 178                 UnlinkFree(chunk);
 179         }
 180
 181         AllocChunkPtr next = chunk->ChunkAtOffset(size);
 182         if (!next->InUse())   /* consolidate forward */
 183         {
 184                 size += next->Size();
 185                 UnlinkFree(next);
 186         }
 187
 188         chunk->SetSizeFree(size);
 189         if (mAreaMoreSize && chunk->IsArea()) {
 190                 // whole area is free
 191                 FreeArea(chunk);
 192         } else {
 193                 LinkFree(chunk);
 194         }
 195         check_pool();
 196 }
 197
 198
 199
 200 AllocAreaPtr AllocPool::NewArea(size_t inAreaSize)
 201 {
 202         void *ptr = (AllocAreaPtr)(mAllocArea)(inAreaSize + kAreaOverhead);
 203
 204         if (ptr == NULL)
 205                 throw std::runtime_error(std::string("Could not allocate new area"));
 206
 207         // AllocAreaPtr area = (AllocAreaPtr)((unsigned long)ptr & ~kAlignMask);
 208         AllocAreaPtr area = (AllocAreaPtr)(((size_t)ptr + kAlignMask) & ~kAlignMask);
 209         assert((area >= ptr) && ((void*)((size_t)area & ~kAlignMask) == area));
 210
 211         area->mUnalignedPointerToThis = ptr;
 212
 213         /* link in area */
 214         if (mAreas) {
 215                 area->mNext = mAreas;
 216                 area->mPrev = mAreas->mPrev;
 217                 area->mNext->mPrev = area;
 218                 area->mPrev->mNext = area;
 219         } else {
 220                 area->mNext = area;
 221                 area->mPrev = area;
 222         }
 223         mAreas = area;
 224
 225         /* set area size */
 226         area->mSize = inAreaSize;
 227         area->mChunk.BeEmpty();
 228         area->mChunk.SetNeighborsInUse(inAreaSize);
 229         area->mChunk.SetSizeFree(inAreaSize);
 230
 231         return area;
 232 }
 233
 234 void AllocPool::FreeArea(AllocChunkPtr chunk)
 235 {
 236         AllocAreaPtr area = (AllocAreaPtr)((char*)chunk - sizeof(AllocAreaHdr));
 237
 238         if (area->mNext == area) {
 239                 mAreas = NULL;
 240         } else {
 241                 /* unlink area */
 242                 mAreas = area->mPrev->mNext = area->mNext;
 243                 area->mNext->mPrev = area->mPrev;
 244         }
 245
 246         (mFreeArea)(area->mUnalignedPointerToThis);
 247 }
 248
 249
 250 size_t AllocPool::TotalFree()
 251 {
 252         size_t total = 0;
 253         for (int i=0; i<kNumAllocBins; ++i) {
 254                 AllocChunkPtr bin = mBins + i;
 255                 if (bin->Prev() != bin) {
 256                         for (AllocChunkPtr candidate = bin->Prev(); candidate != bin; candidate = candidate->Prev()) {
 257                                 total += candidate->Size();
 258                         }
 259                 }
 260         }
 261         return total;
 262 }
 263
 264 size_t AllocPool::LargestFreeChunk()
 265 {
 266         int word = 0;
 267         for (int i=3; i>=0; --i) {
 268                 if (mBinBlocks[i]) {
 269                         word = i;
 270                         break;
 271                 }
 272         }
 273         int binBits = (int)mBinBlocks[word];
 274         int bitPosition = NUMBITS(binBits) - 1;
 275         int index = (word << 5) + bitPosition;
 276         AllocChunkPtr bin = mBins + index;
 277         //postbuf("** %p %p %p %p\n", mBinBlocks[0], mBinBlocks[1], mBinBlocks[2], mBinBlocks[3]);
 278         //postbuf("%d %d %d %p    %p %p\n", word, bitPosition, index, binBits, bin->Prev(), bin->Next());
 279
 280         AllocChunkPtr candidate;
 281         size_t maxsize = 0;
 282         for (candidate = bin->Prev(); candidate != bin; candidate = candidate->Prev()) {
 283                 size_t candidate_size = candidate->Size();
 284                 maxsize = sc_max(maxsize, candidate_size);
 285                 //postbuf("  %d %d\n", maxsize, candidate_size);
 286         }
 287
 288         /*for (int i=0; i<kNumAllocBins; ++i) {
 289                 bin = mBins + i;
 290                 if (bin->Prev() != bin) {
 291                         postbuf("*  %d %d\n", i, bin->Prev()->Size());
 292                 }
 293         }*/
 294         return maxsize;
 295 }
 296
 297 void* AllocPool::Alloc(size_t inReqSize)
 298 {
 299 #ifdef DISABLE_MEMORY_POOLS
 300         return malloc(inReqSize);
 301 #endif
 302
 303         // OK it has a lot of gotos, but these remove a whole lot of common code
 304         // that was obfuscating the original version of this function.
 305         // So here I am choosing the OnceAndOnlyOnce principle over the caveats on gotos.
 306         // The gotos only jump forward and only to the exit paths of the function
 307
 308         // The old bin block scheme has been replaced by 4 x 32 bit words so that each bin has a bit
 309         // and the next bin is found using a count leading zeroes instruction. Much faster.
 310         // Also now each bin's flag can be kept accurate. This simplifies the searching code quite a bit.
 311
 312         // Also fwiw, changed 'victim' in the original code to 'candidate'. 'victim' just bothered me.
 313
 314
 315         AllocChunkPtr   candidate;        /* inspected/selected chunk */
 316         size_t                  candidate_size;   /* its size */
 317         AllocChunkPtr   remainder;        /* remainder from a split */
 318         int32                   remainder_size;   /* its size */
 319         AllocAreaPtr    area;
 320         size_t                  areaSize;
 321
 322         size_t size = RequestToSize(inReqSize);
 323         int index = BinIndex(size);
 324         assert(index < 128);
 325         AllocChunkPtr bin = mBins + index;
 326
 327         check_pool();
 328
 329         /* Check for exact match in a bin */
 330         if (index < kMaxSmallBin) { /* Faster version for small requests */
 331                 /* No traversal or size check necessary for small bins.  */
 332                 candidate = bin->Prev();
 333
 334                 /* Also scan the next one, since it would have a remainder < kMinAllocSize */
 335                 if (candidate == bin) candidate = (++bin)->Prev();
 336                 if (candidate != bin) {
 337                         candidate_size = candidate->Size();
 338                         goto found_exact_fit;
 339                 }
 340
 341                 index += 2; /* Set for bin scan below. We've already scanned 2 bins. */
 342         } else {
 343                 for (candidate = bin->Prev(); candidate != bin; candidate = candidate->Prev()) {
 344
 345                         candidate_size = candidate->Size();
 346                         remainder_size = (int)(candidate_size - size);
 347                         if (remainder_size >= (int32)kMinAllocSize) { /* too big */
 348                                 --index; /* adjust to rescan below after checking last remainder */
 349                                 break;
 350                         } else if (remainder_size >= 0) { /* exact fit */
 351                                 goto found_exact_fit;
 352                         }
 353                 }
 354                 ++index;
 355         }
 356
 357         for(; (index = NextFullBin(index)) >= 0; ++index) {
 358                 bin = mBins + index;
 359
 360                 /* Find and use first big enough chunk ... */
 361                 for (candidate = bin->Prev(); candidate != bin; candidate = candidate->Prev()) {
 362                         candidate_size = candidate->Size();
 363                         remainder_size = (int)(candidate_size - size);
 364                         if (remainder_size >= (int32)kMinAllocSize) { /* split */
 365                                 UnlinkFree(candidate);
 366                                 goto found_bigger_fit;
 367                         } else if (remainder_size >= 0) goto found_exact_fit;
 368                 }
 369         }
 370         check_pool();
 371
 372         if (mAreaMoreSize == 0) { /* pool has a non-growable area */
 373                 if (mAreas != NULL /* fixed size area exhausted */
 374                                 || size > mAreaInitSize)  /* too big anyway */
 375                         goto found_nothing;
 376                 areaSize = mAreaInitSize;
 377                 goto split_new_area;
 378         }
 379
 380         if (size > mAreaMoreSize) {
 381                 areaSize = size;
 382                 goto whole_new_area;
 383         } else {
 384                 areaSize = mAreaMoreSize;
 385                 goto split_new_area;
 386         }
 387
 388         // exit paths:
 389         found_nothing:
 390                 //ipostbuf("alloc failed. size: %d\n", inReqSize);
 391                 throw std::runtime_error(std::string("alloc failed, increase server's memory allocation (e.g. via ServerOptions)"));
 392
 393         whole_new_area:
 394                 //ipostbuf("whole_new_area\n");
 395                 area = NewArea(areaSize);
 396                 if (!area) return 0;
 397                 candidate = &area->mChunk;
 398                 candidate_size = candidate->Size();
 399                 goto return_chunk;
 400
 401         split_new_area:
 402                 //ipostbuf("split_new_area\n");
 403                 area = NewArea(areaSize);
 404                 if (!area) return 0;
 405                 candidate = &area->mChunk;
 406                 candidate_size = candidate->Size();
 407                 remainder_size = (int)(areaSize - size);
 408                 //      FALL THROUGH
 409         found_bigger_fit:
 410                 //ipostbuf("found_bigger_fit\n");
 411                 remainder = candidate->ChunkAtOffset(size);
 412                 remainder->SetSizeFree(remainder_size);
 413                 candidate_size -= remainder_size;
 414                 LinkFree(remainder);
 415                 goto return_chunk;
 416
 417         found_exact_fit:
 418                         check_pool();
 419                 UnlinkFree(candidate);
 420                 //      FALL THROUGH
 421         return_chunk:
 422
 423                 candidate->SetSizeInUse(candidate_size);
 424                         check_malloced_chunk(candidate, candidate_size);
 425                         check_pool();
 426                         garbage_fill(candidate);
 427                 return candidate->ToPtr();
 428 }
 429
 430
 431 void* AllocPool::Realloc(void* inPtr, size_t inReqSize)
 432 {
 433 #ifdef DISABLE_MEMORY_POOLS
 434         return realloc(inPtr, inReqSize);
 435 #endif
 436
 437
 438         void *outPtr;
 439         AllocChunkPtr prev;
 440         check_pool();
 441         bool docopy = false;
 442
 443         /* realloc of null is supposed to be same as malloc */
 444         if (inPtr == 0) return Alloc(inReqSize);
 445
 446         AllocChunkPtr oldChunk = MemToChunk(inPtr);
 447         AllocChunkPtr newChunk = oldChunk;
 448         size_t oldsize = oldChunk->Size();
 449         size_t newsize = oldsize;
 450         size_t size = RequestToSize(inReqSize);
 451         size_t nextsize, prevsize;
 452                 check_inuse_chunk(oldChunk);
 453
 454         if (oldsize < size) {
 455                 /* Try expanding forward */
 456                 AllocChunkPtr next = oldChunk->NextChunk();
 457                 if (!next->InUse()) {
 458                         nextsize = next->Size();
 459                         /* Forward into next chunk */
 460                         if (nextsize + newsize >= size) {
 461                                 UnlinkFree(next);
 462                                 newsize  += nextsize;
 463                                 goto split;
 464                         }
 465                 } else {
 466                         next = 0;
 467                         nextsize = 0;
 468                 }
 469
 470
 471                 /* Try shifting backwards. */
 472                 prev = oldChunk->PrevChunk();
 473                 if (!prev->InUse()) {
 474                         prevsize = prev->Size();
 475
 476                         /* try forward + backward first to save a later consolidation */
 477                         if (next != 0) {
 478                                 /* into next chunk */
 479                                 if (nextsize + prevsize + newsize >= size) {
 480                                         newsize += nextsize + prevsize;
 481                                         UnlinkFree(next);
 482                                         goto alloc_prev;
 483                                 }
 484                         }
 485
 486                         /* backward only */
 487                         if (prev != 0 && prevsize + newsize >= size) {
 488                                 newsize += prevsize;
 489                                 goto alloc_prev;
 490                         }
 491                 }
 492
 493                 /* Must allocate */
 494
 495                 outPtr = Alloc(inReqSize);
 496
 497                 check_pool();
 498                 if (outPtr == 0) {
 499                         //ipostbuf("realloc failed. size: %d\n", inReqSize);
 500                         throw std::runtime_error(std::string("realloc failed, increase server's memory allocation (e.g. via ServerOptions)"));
 501                 }
 502
 503                 /* Otherwise copy, free, and exit */
 504                 memcpy(outPtr, inPtr, oldsize - sizeof(AllocChunk));
 505                 Free(inPtr);
 506                 return outPtr;
 507         } else goto split;
 508
 509         alloc_prev:
 510                 UnlinkFree(prev);
 511                 newChunk = prev;
 512                 docopy = true;
 513                 // FALL THROUGH
 514         split:  /* split off extra room in old or expanded chunk */
 515                 //check_pool();
 516                 if (newsize - size >= kMinAllocSize) { /* split off remainder */
 517                         size_t remainder_size = newsize - size;
 518                         AllocChunkPtr remainder = newChunk->ChunkAtOffset(size);
 519                         remainder->SetSizeInUse(remainder_size);
 520                         newChunk->SetSizeInUse(size);
 521                         Free(remainder->ToPtr()); /* let free() deal with it */
 522                 } else {
 523                         newChunk->SetSizeInUse(newsize);
 524                 }
 525                 outPtr = newChunk->ToPtr();
 526                 if (docopy) {
 527                         memmove(outPtr, inPtr, oldsize - sizeof(AllocChunk));
 528                 }
 529                 check_inuse_chunk(newChunk);
 530                 check_pool();
 531                 garbage_fill(newChunk);
 532         return outPtr;
 533 }
 534
 535 void AllocPool::LinkFree(AllocChunkPtr inChunk)
 536 {
 537         size_t size = inChunk->Size();
 538         size_t index = BinIndex(size);
 539
 540         AllocChunkPtr bin = mBins + index;
 541
 542         if (index < kNumSmallBins || bin->IsEmpty()) {
 543                 inChunk->InsertAfter(bin);
 544                 MarkBinBlock(index);
 545         } else {
 546                 AllocChunkPtr link = bin->Next();
 547                 while (link != bin && size < link->Size()) link = link->Next();
 548                 inChunk->InsertBefore(link);
 549         }
 550 }
 551
 552 void AllocPool::DoCheckArea(AllocAreaPtr area)
 553 {
 554         assert(area->mChunk.PrevInUse());
 555
 556         AllocChunkPtr p = &area->mChunk;
 557         while (p->mSize != kChunkInUse) {
 558                 if (p->InUse()) {
 559                         DoCheckInUseChunk(p);
 560                 } else {
 561                         DoCheckFreeChunk(p);
 562                 }
 563                 p = p->NextChunk();
 564         }
 565 }
 566
 567 void AllocPool::DoCheckBin(AllocChunkPtr bin, long index)
 568 {
 569         AllocChunkPtr p = bin->Next();
 570
 571         while (p != bin) {
 572                 assert(BinIndex(p->Size()) == index);
 573                 DoCheckFreeChunk(p);
 574                 p = p->Next();
 575         }
 576 }
 577
 578
 579 void AllocPool::DoCheckPool()
 580 {
 581         AllocAreaPtr area = mAreas;
 582         if (area) {
 583                 do {
 584                         AllocAreaPtr nextarea = area->mNext;
 585                         DoCheckArea(area);
 586                         area = nextarea;
 587                 } while (area != mAreas);
 588         }
 589
 590         for (int i=0; i<kNumAllocBins; ++i) {
 591                 AllocChunkPtr b = mBins + i;
 592                 DoCheckBin(b, i);
 593         }
 594 }
 595
 596
 597 void AllocPool::DoCheckChunk(AllocChunkPtr p)
 598 {
 599 #ifndef NDEBUG
 600   size_t size = p->Size();
 601   //size_t maxsize = mAreaInitSize > mAreaMoreSize ? mAreaInitSize : mAreaMoreSize;
 602  // assert(size < maxsize);
 603
 604   AllocChunkPtr next = p->ChunkAtOffset(size);
 605 #endif
 606   assert(p->mSize == next->mPrevSize);
 607 }
 608
 609
 610 void AllocPool::DoCheckFreeChunk(AllocChunkPtr p)
 611 {
 612   size_t size = p->Size();
 613 #ifndef NDEBUG
 614   AllocChunkPtr next = p->ChunkAtOffset(size);
 615 #endif
 616   DoCheckChunk(p);
 617
 618   /* Check whether it claims to be free ... */
 619   assert(!p->InUse());
 620
 621   /* Unless an end marker, must have OK fields */
 622   if (size >= kMinAllocSize)
 623   {
 624     assert((size & kAlignMask) == 0);
 625     assert(aligned_OK(p->ToPtr()));
 626     /* ... and is fully consolidated */
 627     assert(p->PrevInUse());
 628     assert(next->InUse());
 629
 630     /* ... and has minimally sane links */
 631         assert(p->Next()->Prev() == p);
 632         assert(p->Prev()->Next() == p);
 633   }
 634   else /* end markers are always of size 0 */
 635     assert(size == 0);
 636 }
 637
 638 void AllocPool::DoCheckInUseChunk(AllocChunkPtr p)
 639 {
 640         size_t size = p->Size();
 641         AllocChunkPtr next = p->NextChunk();
 642
 643         DoCheckChunk(p);
 644
 645         /* Check whether it claims to be in use ... */
 646         assert(p->InUse());
 647
 648         /* ... and is surrounded by OK chunks.
 649         Since more things can be checked with free chunks than inuse ones,
 650         if an inuse chunk borders them and debug is on, it's worth doing them.
 651         */
 652         if (!p->PrevInUse()) {
 653                 size_t prevsize = p->PrevSize();
 654                 if (prevsize > 0) {
 655                         AllocChunkPtr prv = p->PrevChunk();
 656                         assert(prv->NextChunk() == p);
 657                         DoCheckFreeChunk(prv);
 658                 }
 659         }
 660         if (!p->ChunkAtOffset(size)->InUse()) {
 661                 DoCheckFreeChunk(next);
 662         }
 663 }
 664
 665 void AllocPool::DoCheckAllocedChunk(AllocChunkPtr p, size_t s)
 666 {
 667 #ifndef NDEBUG
 668   size_t size = p->Size();
 669   long room = size - s;
 670 #endif
 671
 672   DoCheckInUseChunk(p);
 673
 674   /* Legal size ... */
 675   assert(size >= kMinAllocSize);
 676   assert((size & kAlignMask) == 0);
 677   assert(room >= 0);
 678   assert(room < kMinAllocSize);
 679
 680   /* ... and alignment */
 681   assert(aligned_OK(p->ToPtr()));
 682
 683
 684   /* ... and was allocated at front of an available chunk */
 685   assert(p->PrevInUse());  // huh??  - jmc
 686
 687 }
 688
 689 void AllocPool::DoGarbageFill(AllocChunkPtr p)
 690 {
 691         long size = (p->Size() - sizeof(AllocChunk));
 692         DoGarbageFill(p, size);
 693 }
 694
 695 void AllocPool::DoGarbageFill(AllocChunkPtr p, long size)
 696 {
 697         size /= sizeof(long);
 698         long *ptr = (long*)p->ToPtr();
 699         for (int i=0; i<size; ++i) {
 700                 ptr[i] = 0xA3A56955;
 701         }
 702 }
 703
 704