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 hl com"> * * This is a very fast storage allocator. It allocates blocks of a small * number of different sizes, and keeps free lists of each size. Blocks * that don't exactly fit are passed up to the next larger size. Blocks * over a certain size are directly allocated from the system. * * Copyright (c) 1983 Regents of the University of California. * Copyright (c) 1996-1997 Sun Microsystems, Inc. * Copyright (c) 1998-1999 by Scriptics Corporation. * * Portions contributed by Chris Kingsley, Jack Jansen and Ray Johnson. * * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. */ /* * Windows and Unix use an alternative allocator when building with threads * that has significantly reduced lock contention. */ #include "tclInt.h" #if !defined(TCL_THREADS) || !defined(USE_THREAD_ALLOC) #if USE_TCLALLOC /* * We should really make use of AC_CHECK_TYPE(caddr_t) here, but it can wait * until Tcl uses config.h properly. */ #if defined(_MSC_VER) || defined(__MSVCRT__) || defined(__BORLANDC__) typedef size_t caddr_t; #endif /* * The overhead on a block is at least 8 bytes. When free, this space contains * a pointer to the next free block, and the bottom two bits must be zero. * When in use, the first byte is set to MAGIC, and the second byte is the * size index. The remaining bytes are for alignment. If range checking is * enabled then a second word holds the size of the requested block, less 1, * rounded up to a multiple of sizeof(RMAGIC). The order of elements is * critical: ov.magic must overlay the low order bits of ov.next, and ov.magic * can not be a valid ov.next bit pattern. */ union overhead { union overhead *next; /* when free */ unsigned char padding[TCL_ALLOCALIGN]; /* align struct to TCL_ALLOCALIGN bytes */ struct { unsigned char magic0; /* magic number */ unsigned char index; /* bucket # */ unsigned char unused; /* unused */ unsigned char magic1; /* other magic number */ #ifndef NDEBUG unsigned short rmagic; /* range magic number */ size_t size; /* actual block size */ unsigned short unused2; /* padding to 8-byte align */ #endif } ovu; #define overMagic0 ovu.magic0 #define overMagic1 ovu.magic1 #define bucketIndex ovu.index #define rangeCheckMagic ovu.rmagic #define realBlockSize ovu.size }; #define MAGIC 0xef /* magic # on accounting info */ #define RMAGIC 0x5555 /* magic # on range info */ #ifndef NDEBUG #define RSLOP sizeof(unsigned short) #else #define RSLOP 0 #endif #define OVERHEAD (sizeof(union overhead) + RSLOP) /* * Macro to make it easier to refer to the end-of-block guard magic. */ #define BLOCK_END(overPtr) \ (*(unsigned short *)((caddr_t)((overPtr) + 1) + (overPtr)->realBlockSize)) /* * nextf[i] is the pointer to the next free block of size 2^(i+3). The * smallest allocatable block is MINBLOCK bytes. The overhead information * precedes the data area returned to the user. */ #define MINBLOCK ((sizeof(union overhead) + (TCL_ALLOCALIGN-1)) & ~(TCL_ALLOCALIGN-1)) #define NBUCKETS (13 - (MINBLOCK >> 4)) #define MAXMALLOC (1<<(NBUCKETS+2)) static union overhead *nextf[NBUCKETS]; /* * The following structure is used to keep track of all system memory * currently owned by Tcl. When finalizing, all this memory will be returned * to the system. */ struct block { struct block *nextPtr; /* Linked list. */ struct block *prevPtr; /* Linked list for big blocks, ensures 8-byte * alignment for suballocated blocks. */ }; static struct block *blockList; /* Tracks the suballocated blocks. */ static struct block bigBlocks={ /* Big blocks aren't suballocated. */ &bigBlocks, &bigBlocks }; /* * The allocator is protected by a special mutex that must be explicitly * initialized. Futhermore, because Tcl_Alloc may be used before anything else * in Tcl, we make this module self-initializing after all with the allocInit * variable. */ #ifdef TCL_THREADS static Tcl_Mutex *allocMutexPtr; #endif static int allocInit = 0; #ifdef MSTATS /* * numMallocs[i] is the difference between the number of mallocs and frees for * a given block size. */ static size_t numMallocs[NBUCKETS+1]; #endif #if !defined(NDEBUG) #define ASSERT(p) if (!(p)) Tcl_Panic(# p) #define RANGE_ASSERT(p) if (!(p)) Tcl_Panic(# p) #else #define ASSERT(p) #define RANGE_ASSERT(p) #endif /* * Prototypes for functions used only in this file. */ static void MoreCore(size_t bucket); /* *------------------------------------------------------------------------- * * TclInitAlloc -- * * Initialize the memory system. * * Results: * None. * * Side effects: * Initialize the mutex used to serialize allocations. * *------------------------------------------------------------------------- */ void TclInitAlloc(void) { if (!allocInit) { allocInit = 1; #ifdef TCL_THREADS allocMutexPtr = Tcl_GetAllocMutex(); #endif } } /* *------------------------------------------------------------------------- * * TclFinalizeAllocSubsystem -- * * Release all resources being used by this subsystem, including * aggressively freeing all memory allocated by TclpAlloc() that has not * yet been released with TclpFree(). * * After this function is called, all memory allocated with TclpAlloc() * should be considered unusable. * * Results: * None. * * Side effects: * This subsystem is self-initializing, since memory can be allocated * before Tcl is formally initialized. After this call, this subsystem * has been reset to its initial state and is usable again. * *------------------------------------------------------------------------- */ void TclFinalizeAllocSubsystem(void) { unsigned int i; struct block *blockPtr, *nextPtr; Tcl_MutexLock(allocMutexPtr); for (blockPtr = blockList; blockPtr != NULL; blockPtr = nextPtr) { nextPtr = blockPtr->nextPtr; TclpSysFree(blockPtr); } blockList = NULL; for (blockPtr = bigBlocks.nextPtr; blockPtr != &bigBlocks; ) { nextPtr = blockPtr->nextPtr; TclpSysFree(blockPtr); blockPtr = nextPtr; } bigBlocks.nextPtr = &bigBlocks; bigBlocks.prevPtr = &bigBlocks; for (i=0 ; i<NBUCKETS ; i++) { nextf[i] = NULL; #ifdef MSTATS numMallocs[i] = 0; #endif } #ifdef MSTATS numMallocs[i] = 0; #endif Tcl_MutexUnlock(allocMutexPtr); } /* *---------------------------------------------------------------------- * * TclpAlloc -- * * Allocate more memory. * * Results: * None. * * Side effects: * None. * *---------------------------------------------------------------------- */ char * TclpAlloc( unsigned int numBytes) /* Number of bytes to allocate. */ { register union overhead *overPtr; register size_t bucket; register unsigned amount; struct block *bigBlockPtr = NULL; if (!allocInit) { /* * We have to make the "self initializing" because Tcl_Alloc may be * used before any other part of Tcl. E.g., see main() for tclsh! */ TclInitAlloc(); } Tcl_MutexLock(allocMutexPtr); /* * First the simple case: we simple allocate big blocks directly. */ if (numBytes >= MAXMALLOC - OVERHEAD) { if (numBytes <= UINT_MAX - OVERHEAD -sizeof(struct block)) { bigBlockPtr = (struct block *) TclpSysAlloc((unsigned) (sizeof(struct block) + OVERHEAD + numBytes), 0); } if (bigBlockPtr == NULL) { Tcl_MutexUnlock(allocMutexPtr); return NULL; } bigBlockPtr->nextPtr = bigBlocks.nextPtr; bigBlocks.nextPtr = bigBlockPtr; bigBlockPtr->prevPtr = &bigBlocks; bigBlockPtr->nextPtr->prevPtr = bigBlockPtr; overPtr = (union overhead *) (bigBlockPtr + 1); overPtr->overMagic0 = overPtr->overMagic1 = MAGIC; overPtr->bucketIndex = 0xff; #ifdef MSTATS numMallocs[NBUCKETS]++; #endif #ifndef NDEBUG /* * Record allocated size of block and bound space with magic numbers. */ overPtr->realBlockSize = (numBytes + RSLOP - 1) & ~(RSLOP - 1); overPtr->rangeCheckMagic = RMAGIC; BLOCK_END(overPtr) = RMAGIC; #endif Tcl_MutexUnlock(allocMutexPtr); return (void *)(overPtr+1); } /* * Convert amount of memory requested into closest block size stored in * hash buckets which satisfies request. Account for space used per block * for accounting. */ amount = MINBLOCK; /* size of first bucket */ bucket = MINBLOCK >> 4; while (numBytes + OVERHEAD > amount) { amount <<= 1; if (amount == 0) { Tcl_MutexUnlock(allocMutexPtr); return NULL; } bucket++; } ASSERT(bucket < NBUCKETS); /* * If nothing in hash bucket right now, request more memory from the * system. */ if ((overPtr = nextf[bucket]) == NULL) { MoreCore(bucket); if ((overPtr = nextf[bucket]) == NULL) { Tcl_MutexUnlock(allocMutexPtr); return NULL; } } /* * Remove from linked list */ nextf[bucket] = overPtr->next; overPtr->overMagic0 = overPtr->overMagic1 = MAGIC; overPtr->bucketIndex = (unsigned char) bucket; #ifdef MSTATS numMallocs[bucket]++; #endif #ifndef NDEBUG /* * Record allocated size of block and bound space with magic numbers. */ overPtr->realBlockSize = (numBytes + RSLOP - 1) & ~(RSLOP - 1); overPtr->rangeCheckMagic = RMAGIC; BLOCK_END(overPtr) = RMAGIC; #endif Tcl_MutexUnlock(allocMutexPtr); return ((char *)(overPtr + 1)); } /* *---------------------------------------------------------------------- * * MoreCore -- * * Allocate more memory to the indicated bucket. * * Assumes Mutex is already held. * * Results: * None. * * Side effects: * Attempts to get more memory from the system. * *---------------------------------------------------------------------- */ static void MoreCore( size_t bucket) /* What bucket to allocate to. */ { register union overhead *overPtr; register size_t size; /* size of desired block */ size_t amount; /* amount to allocate */ size_t numBlocks; /* how many blocks we get */ struct block *blockPtr; /* * sbrk_size <= 0 only for big, FLUFFY, requests (about 2^30 bytes on a * VAX, I think) or for a negative arg. */ size = ((size_t)1) << (bucket + 3); ASSERT(size > 0); amount = MAXMALLOC; numBlocks = amount / size; ASSERT(numBlocks*size == amount); blockPtr = (struct block *) TclpSysAlloc( (sizeof(struct block) + amount), 1); /* no more room! */ if (blockPtr == NULL) { return; } blockPtr->nextPtr = blockList; blockList = blockPtr; overPtr = (union overhead *) (blockPtr + 1); /* * Add new memory allocated to that on free list for this hash bucket. */ nextf[bucket] = overPtr; while (--numBlocks > 0) { overPtr->next = (union overhead *)((caddr_t)overPtr + size); overPtr = (union overhead *)((caddr_t)overPtr + size); } overPtr->next = NULL; } /* *---------------------------------------------------------------------- * * TclpFree -- * * Free memory. * * Results: * None. * * Side effects: * None. * *---------------------------------------------------------------------- */ void TclpFree( char *oldPtr) /* Pointer to memory to free. */ { register size_t size; register union overhead *overPtr; struct block *bigBlockPtr; if (oldPtr == NULL) { return; } Tcl_MutexLock(allocMutexPtr); overPtr = (union overhead *)((caddr_t)oldPtr - sizeof(union overhead)); ASSERT(overPtr->overMagic0 == MAGIC); /* make sure it was in use */ ASSERT(overPtr->overMagic1 == MAGIC); if (overPtr->overMagic0 != MAGIC || overPtr->overMagic1 != MAGIC) { Tcl_MutexUnlock(allocMutexPtr); return; } RANGE_ASSERT(overPtr->rangeCheckMagic == RMAGIC); RANGE_ASSERT(BLOCK_END(overPtr) == RMAGIC); size = overPtr->bucketIndex; if (size == 0xff) { #ifdef MSTATS numMallocs[NBUCKETS]--; #endif bigBlockPtr = (struct block *) overPtr - 1; bigBlockPtr->prevPtr->nextPtr = bigBlockPtr->nextPtr; bigBlockPtr->nextPtr->prevPtr = bigBlockPtr->prevPtr; TclpSysFree(bigBlockPtr); Tcl_MutexUnlock(allocMutexPtr); return; } ASSERT(size < NBUCKETS); overPtr->next = nextf[size]; /* also clobbers overMagic */ nextf[size] = overPtr; #ifdef MSTATS numMallocs[size]--; #endif Tcl_MutexUnlock(allocMutexPtr); } /* *---------------------------------------------------------------------- * * TclpRealloc -- * * Reallocate memory. * * Results: * None. * * Side effects: * None. * *---------------------------------------------------------------------- */ char * TclpRealloc( char *oldPtr, /* Pointer to alloced block. */ unsigned int numBytes) /* New size of memory. */ { int i; union overhead *overPtr; struct block *bigBlockPtr; int expensive; size_t maxSize; if (oldPtr == NULL) { return TclpAlloc(numBytes); } Tcl_MutexLock(allocMutexPtr); overPtr = (union overhead *)((caddr_t)oldPtr - sizeof(union overhead)); ASSERT(overPtr->overMagic0 == MAGIC); /* make sure it was in use */ ASSERT(overPtr->overMagic1 == MAGIC); if (overPtr->overMagic0 != MAGIC || overPtr->overMagic1 != MAGIC) { Tcl_MutexUnlock(allocMutexPtr); return NULL; } RANGE_ASSERT(overPtr->rangeCheckMagic == RMAGIC); RANGE_ASSERT(BLOCK_END(overPtr) == RMAGIC); i = overPtr->bucketIndex; /* * If the block isn't in a bin, just realloc it. */ if (i == 0xff) { struct block *prevPtr, *nextPtr; bigBlockPtr = (struct block *) overPtr - 1; prevPtr = bigBlockPtr->prevPtr; nextPtr = bigBlockPtr->nextPtr; bigBlockPtr = (struct block *) TclpSysRealloc(bigBlockPtr, sizeof(struct block) + OVERHEAD + numBytes); if (bigBlockPtr == NULL) { Tcl_MutexUnlock(allocMutexPtr); return NULL; } if (prevPtr->nextPtr != bigBlockPtr) { /* * If the block has moved, splice the new block into the list * where the old block used to be. */ prevPtr->nextPtr = bigBlockPtr; nextPtr->prevPtr = bigBlockPtr; } overPtr = (union overhead *) (bigBlockPtr + 1); #ifdef MSTATS numMallocs[NBUCKETS]++; #endif #ifndef NDEBUG /* * Record allocated size of block and update magic number bounds. */ overPtr->realBlockSize = (numBytes + RSLOP - 1) & ~(RSLOP - 1); BLOCK_END(overPtr) = RMAGIC; #endif Tcl_MutexUnlock(allocMutexPtr); return (char *)(overPtr+1); } maxSize = 1 << (i+3); expensive = 0; if (numBytes+OVERHEAD > maxSize) { expensive = 1; } else if (i>0 && numBytes+OVERHEAD < maxSize/2) { expensive = 1; } if (expensive) { void *newPtr; Tcl_MutexUnlock(allocMutexPtr); newPtr = TclpAlloc(numBytes); if (newPtr == NULL) { return NULL; } maxSize -= OVERHEAD; if (maxSize < numBytes) { numBytes = maxSize; } memcpy(newPtr, oldPtr, (size_t) numBytes); TclpFree(oldPtr); return newPtr; } /* * Ok, we don't have to copy, it fits as-is */ #ifndef NDEBUG overPtr->realBlockSize = (numBytes + RSLOP - 1) & ~(RSLOP - 1); BLOCK_END(overPtr) = RMAGIC; #endif Tcl_MutexUnlock(allocMutexPtr); return(oldPtr); } /* *---------------------------------------------------------------------- * * mstats -- * * Prints two lines of numbers, one showing the length of the free list * for each size category, the second showing the number of mallocs - * frees for each size category. * * Results: * None. * * Side effects: * None. * *---------------------------------------------------------------------- */ #ifdef MSTATS void mstats( char *s) /* Where to write info. */ { register unsigned int i, j; register union overhead *overPtr; size_t totalFree = 0, totalUsed = 0; Tcl_MutexLock(allocMutexPtr); fprintf(stderr, "Memory allocation statistics %s\nTclpFree:\t", s); for (i = 0; i < NBUCKETS; i++) { for (j=0, overPtr=nextf[i]; overPtr; overPtr=overPtr->next, j++) { fprintf(stderr, " %u", j); } totalFree += ((size_t)j) * (1 << (i + 3)); } fprintf(stderr, "\nused:\t"); for (i = 0; i < NBUCKETS; i++) { fprintf(stderr, " %" TCL_LL_MODIFIER "d", (Tcl_WideInt)numMallocs[i]); totalUsed += numMallocs[i] * (1 << (i + 3)); } fprintf(stderr, "\n\tTotal small in use: %" TCL_LL_MODIFIER "d, total free: %" TCL_LL_MODIFIER "d\n", (Tcl_WideInt)totalUsed, (Tcl_WideInt)totalFree); fprintf(stderr, "\n\tNumber of big (>%d) blocks in use: %" TCL_LL_MODIFIER "d\n", MAXMALLOC, (Tcl_WideInt)numMallocs[NBUCKETS]); Tcl_MutexUnlock(allocMutexPtr); } #endif #else /* !USE_TCLALLOC */ /* *---------------------------------------------------------------------- * * TclpAlloc -- * * Allocate more memory. * * Results: * None. * * Side effects: * None. * *---------------------------------------------------------------------- */ char * TclpAlloc( unsigned int numBytes) /* Number of bytes to allocate. */ { return (char *) malloc(numBytes); } /* *---------------------------------------------------------------------- * * TclpFree -- * * Free memory. * * Results: * None. * * Side effects: * None. * *---------------------------------------------------------------------- */ void TclpFree( char *oldPtr) /* Pointer to memory to free. */ { free(oldPtr); return; } /* *---------------------------------------------------------------------- * * TclpRealloc -- * * Reallocate memory. * * Results: * None. * * Side effects: * None. * *---------------------------------------------------------------------- */ char * TclpRealloc( char *oldPtr, /* Pointer to alloced block. */ unsigned int numBytes) /* New size of memory. */ { return (char *) realloc(oldPtr, numBytes); } #endif /* !USE_TCLALLOC */ #endif /* !TCL_THREADS */ /* * Local Variables: * mode: c * c-basic-offset: 4 * fill-column: 78 * End: */ |