malloc.c revision 1.3
1/* malloc.c 2 * 3 */ 4 5/* 6 Here are some notes on configuring Perl's malloc. 7 8 There are two macros which serve as bulk disablers of advanced 9 features of this malloc: NO_FANCY_MALLOC, PLAIN_MALLOC (undef by 10 default). Look in the list of default values below to understand 11 their exact effect. Defining NO_FANCY_MALLOC returns malloc.c to the 12 state of the malloc in Perl 5.004. Additionally defining PLAIN_MALLOC 13 returns it to the state as of Perl 5.000. 14 15 Note that some of the settings below may be ignored in the code based 16 on values of other macros. The PERL_CORE symbol is only defined when 17 perl itself is being compiled (so malloc can make some assumptions 18 about perl's facilities being available to it). 19 20 Each config option has a short description, followed by its name, 21 default value, and a comment about the default (if applicable). Some 22 options take a precise value, while the others are just boolean. 23 The boolean ones are listed first. 24 25 # Enable code for an emergency memory pool in $^M. See perlvar.pod 26 # for a description of $^M. 27 PERL_EMERGENCY_SBRK (!PLAIN_MALLOC && PERL_CORE) 28 29 # Enable code for printing memory statistics. 30 DEBUGGING_MSTATS (!PLAIN_MALLOC && PERL_CORE) 31 32 # Move allocation info for small buckets into separate areas. 33 # Memory optimization (especially for small allocations, of the 34 # less than 64 bytes). Since perl usually makes a large number 35 # of small allocations, this is usually a win. 36 PACK_MALLOC (!PLAIN_MALLOC && !RCHECK) 37 38 # Add one page to big powers of two when calculating bucket size. 39 # This is targeted at big allocations, as are common in image 40 # processing. 41 TWO_POT_OPTIMIZE !PLAIN_MALLOC 42 43 # Use intermediate bucket sizes between powers-of-two. This is 44 # generally a memory optimization, and a (small) speed pessimization. 45 BUCKETS_ROOT2 !NO_FANCY_MALLOC 46 47 # Do not check small deallocations for bad free(). Memory 48 # and speed optimization, error reporting pessimization. 49 IGNORE_SMALL_BAD_FREE (!NO_FANCY_MALLOC && !RCHECK) 50 51 # Use table lookup to decide in which bucket a given allocation will go. 52 SMALL_BUCKET_VIA_TABLE !NO_FANCY_MALLOC 53 54 # Use a perl-defined sbrk() instead of the (presumably broken or 55 # missing) system-supplied sbrk(). 56 USE_PERL_SBRK undef 57 58 # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally 59 # only used with broken sbrk()s. 60 PERL_SBRK_VIA_MALLOC undef 61 62 # Which allocator to use if PERL_SBRK_VIA_MALLOC 63 SYSTEM_ALLOC(a) malloc(a) 64 65 # Disable memory overwrite checking with DEBUGGING. Memory and speed 66 # optimization, error reporting pessimization. 67 NO_RCHECK undef 68 69 # Enable memory overwrite checking with DEBUGGING. Memory and speed 70 # pessimization, error reporting optimization 71 RCHECK (DEBUGGING && !NO_RCHECK) 72 73 # Failed allocations bigger than this size croak (if 74 # PERL_EMERGENCY_SBRK is enabled) without touching $^M. See 75 # perlvar.pod for a description of $^M. 76 BIG_SIZE (1<<16) # 64K 77 78 # Starting from this power of two, add an extra page to the 79 # size of the bucket. This enables optimized allocations of sizes 80 # close to powers of 2. Note that the value is indexed at 0. 81 FIRST_BIG_POW2 15 # 32K, 16K is used too often 82 83 # Estimate of minimal memory footprint. malloc uses this value to 84 # request the most reasonable largest blocks of memory from the system. 85 FIRST_SBRK (48*1024) 86 87 # Round up sbrk()s to multiples of this. 88 MIN_SBRK 2048 89 90 # Round up sbrk()s to multiples of this percent of footprint. 91 MIN_SBRK_FRAC 3 92 93 # Add this much memory to big powers of two to get the bucket size. 94 PERL_PAGESIZE 4096 95 96 # This many sbrk() discontinuities should be tolerated even 97 # from the start without deciding that sbrk() is usually 98 # discontinuous. 99 SBRK_ALLOW_FAILURES 3 100 101 # This many continuous sbrk()s compensate for one discontinuous one. 102 SBRK_FAILURE_PRICE 50 103 104 # Some configurations may ask for 12-byte-or-so allocations which 105 # require 8-byte alignment (?!). In such situation one needs to 106 # define this to disable 12-byte bucket (will increase memory footprint) 107 STRICT_ALIGNMENT undef 108 109 This implementation assumes that calling PerlIO_printf() does not 110 result in any memory allocation calls (used during a panic). 111 112 */ 113 114#ifndef NO_FANCY_MALLOC 115# ifndef SMALL_BUCKET_VIA_TABLE 116# define SMALL_BUCKET_VIA_TABLE 117# endif 118# ifndef BUCKETS_ROOT2 119# define BUCKETS_ROOT2 120# endif 121# ifndef IGNORE_SMALL_BAD_FREE 122# define IGNORE_SMALL_BAD_FREE 123# endif 124#endif 125 126#ifndef PLAIN_MALLOC /* Bulk enable features */ 127# ifndef PACK_MALLOC 128# define PACK_MALLOC 129# endif 130# ifndef TWO_POT_OPTIMIZE 131# define TWO_POT_OPTIMIZE 132# endif 133# if defined(PERL_CORE) && !defined(PERL_EMERGENCY_SBRK) 134# define PERL_EMERGENCY_SBRK 135# endif 136# if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS) 137# define DEBUGGING_MSTATS 138# endif 139#endif 140 141#define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */ 142#define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2) 143 144#if !(defined(I286) || defined(atarist) || defined(__MINT__)) 145 /* take 2k unless the block is bigger than that */ 146# define LOG_OF_MIN_ARENA 11 147#else 148 /* take 16k unless the block is bigger than that 149 (80286s like large segments!), probably good on the atari too */ 150# define LOG_OF_MIN_ARENA 14 151#endif 152 153#ifndef lint 154# if defined(DEBUGGING) && !defined(NO_RCHECK) 155# define RCHECK 156# endif 157# if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE) 158# undef IGNORE_SMALL_BAD_FREE 159# endif 160/* 161 * malloc.c (Caltech) 2/21/82 162 * Chris Kingsley, kingsley@cit-20. 163 * 164 * This is a very fast storage allocator. It allocates blocks of a small 165 * number of different sizes, and keeps free lists of each size. Blocks that 166 * don't exactly fit are passed up to the next larger size. In this 167 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long. 168 * If PACK_MALLOC is defined, small blocks are 2^n bytes long. 169 * This is designed for use in a program that uses vast quantities of memory, 170 * but bombs when it runs out. 171 */ 172 173#ifdef PERL_CORE 174# include "EXTERN.h" 175# include "perl.h" 176#else 177# ifdef PERL_FOR_X2P 178# include "../EXTERN.h" 179# include "../perl.h" 180# else 181# include <stdlib.h> 182# include <stdio.h> 183# include <memory.h> 184# define _(arg) arg 185# ifndef Malloc_t 186# define Malloc_t void * 187# endif 188# ifndef MEM_SIZE 189# define MEM_SIZE unsigned long 190# endif 191# ifndef LONG_MAX 192# define LONG_MAX 0x7FFFFFFF 193# endif 194# ifndef UV 195# define UV unsigned long 196# endif 197# ifndef caddr_t 198# define caddr_t char * 199# endif 200# ifndef Free_t 201# define Free_t void 202# endif 203# define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t)) 204# define PerlEnv_getenv getenv 205# define PerlIO_printf fprintf 206# define PerlIO_stderr() stderr 207# endif 208# ifndef croak /* make depend */ 209# define croak(mess, arg) warn((mess), (arg)); exit(1); 210# endif 211# ifndef warn 212# define warn(mess, arg) fprintf(stderr, (mess), (arg)); 213# endif 214# ifdef DEBUG_m 215# undef DEBUG_m 216# endif 217# define DEBUG_m(a) 218# ifdef DEBUGGING 219# undef DEBUGGING 220# endif 221#endif 222 223#ifndef MUTEX_LOCK 224# define MUTEX_LOCK(l) 225#endif 226 227#ifndef MUTEX_UNLOCK 228# define MUTEX_UNLOCK(l) 229#endif 230 231#ifdef DEBUGGING 232# undef DEBUG_m 233# define DEBUG_m(a) if (PL_debug & 128) a 234#endif 235 236/* I don't much care whether these are defined in sys/types.h--LAW */ 237 238#define u_char unsigned char 239#define u_int unsigned int 240 241#ifdef HAS_QUAD 242# define u_bigint UV /* Needs to eat *void. */ 243#else /* needed? */ 244# define u_bigint unsigned long /* Needs to eat *void. */ 245#endif 246 247#define u_short unsigned short 248 249/* 286 and atarist like big chunks, which gives too much overhead. */ 250#if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC) 251# undef PACK_MALLOC 252#endif 253 254/* 255 * The description below is applicable if PACK_MALLOC is not defined. 256 * 257 * The overhead on a block is at least 4 bytes. When free, this space 258 * contains a pointer to the next free block, and the bottom two bits must 259 * be zero. When in use, the first byte is set to MAGIC, and the second 260 * byte is the size index. The remaining bytes are for alignment. 261 * If range checking is enabled and the size of the block fits 262 * in two bytes, then the top two bytes hold the size of the requested block 263 * plus the range checking words, and the header word MINUS ONE. 264 */ 265union overhead { 266 union overhead *ov_next; /* when free */ 267#if MEM_ALIGNBYTES > 4 268 double strut; /* alignment problems */ 269#endif 270 struct { 271 u_char ovu_magic; /* magic number */ 272 u_char ovu_index; /* bucket # */ 273#ifdef RCHECK 274 u_short ovu_size; /* actual block size */ 275 u_int ovu_rmagic; /* range magic number */ 276#endif 277 } ovu; 278#define ov_magic ovu.ovu_magic 279#define ov_index ovu.ovu_index 280#define ov_size ovu.ovu_size 281#define ov_rmagic ovu.ovu_rmagic 282}; 283 284#ifdef DEBUGGING 285static void botch _((char *diag, char *s)); 286#endif 287static void morecore _((int bucket)); 288static int findbucket _((union overhead *freep, int srchlen)); 289static void add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip); 290 291#define MAGIC 0xff /* magic # on accounting info */ 292#define RMAGIC 0x55555555 /* magic # on range info */ 293#define RMAGIC_C 0x55 /* magic # on range info */ 294 295#ifdef RCHECK 296# define RSLOP sizeof (u_int) 297# ifdef TWO_POT_OPTIMIZE 298# define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2) 299# else 300# define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2) 301# endif 302#else 303# define RSLOP 0 304#endif 305 306#if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2) 307# undef BUCKETS_ROOT2 308#endif 309 310#ifdef BUCKETS_ROOT2 311# define BUCKET_TABLE_SHIFT 2 312# define BUCKET_POW2_SHIFT 1 313# define BUCKETS_PER_POW2 2 314#else 315# define BUCKET_TABLE_SHIFT MIN_BUC_POW2 316# define BUCKET_POW2_SHIFT 0 317# define BUCKETS_PER_POW2 1 318#endif 319 320#if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT)) 321/* Figure out the alignment of void*. */ 322struct aligner { 323 char c; 324 void *p; 325}; 326# define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p))) 327#else 328# define ALIGN_SMALL MEM_ALIGNBYTES 329#endif 330 331#define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no)) 332 333#ifdef BUCKETS_ROOT2 334# define MAX_BUCKET_BY_TABLE 13 335static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] = 336 { 337 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80, 338 }; 339# define BUCKET_SIZE(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT))) 340# define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \ 341 ? buck_size[i] \ 342 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \ 343 - MEM_OVERHEAD(i) \ 344 + POW2_OPTIMIZE_SURPLUS(i))) 345#else 346# define BUCKET_SIZE(i) (1 << ((i) >> BUCKET_POW2_SHIFT)) 347# define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i) + POW2_OPTIMIZE_SURPLUS(i)) 348#endif 349 350 351#ifdef PACK_MALLOC 352/* In this case it is assumed that if we do sbrk() in 2K units, we 353 * will get 2K aligned arenas (at least after some initial 354 * alignment). The bucket number of the given subblock is on the start 355 * of 2K arena which contains the subblock. Several following bytes 356 * contain the magic numbers for the subblocks in the block. 357 * 358 * Sizes of chunks are powers of 2 for chunks in buckets <= 359 * MAX_PACKED, after this they are (2^n - sizeof(union overhead)) (to 360 * get alignment right). 361 * 362 * Consider an arena for 2^n with n>MAX_PACKED. We suppose that 363 * starts of all the chunks in a 2K arena are in different 364 * 2^n-byte-long chunks. If the top of the last chunk is aligned on a 365 * boundary of 2K block, this means that sizeof(union 366 * overhead)*"number of chunks" < 2^n, or sizeof(union overhead)*2K < 367 * 4^n, or n > 6 + log2(sizeof()/2)/2, since a chunk of size 2^n - 368 * overhead is used. Since this rules out n = 7 for 8 byte alignment, 369 * we specialcase allocation of the first of 16 128-byte-long chunks. 370 * 371 * Note that with the above assumption we automatically have enough 372 * place for MAGIC at the start of 2K block. Note also that we 373 * overlay union overhead over the chunk, thus the start of small chunks 374 * is immediately overwritten after freeing. */ 375# define MAX_PACKED_POW2 6 376# define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT) 377# define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD) 378# define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1) 379# define TWOK_MASKED(x) ((u_bigint)(x) & ~TWOK_MASK) 380# define TWOK_SHIFT(x) ((u_bigint)(x) & TWOK_MASK) 381# define OV_INDEXp(block) ((u_char*)(TWOK_MASKED(block))) 382# define OV_INDEX(block) (*OV_INDEXp(block)) 383# define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \ 384 (TWOK_SHIFT(block)>> \ 385 (bucket>>BUCKET_POW2_SHIFT)) + \ 386 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0))) 387 /* A bucket can have a shift smaller than it size, we need to 388 shift its magic number so it will not overwrite index: */ 389# ifdef BUCKETS_ROOT2 390# define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */ 391# else 392# define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */ 393# endif 394# define CHUNK_SHIFT 0 395 396/* Number of active buckets of given ordinal. */ 397#ifdef IGNORE_SMALL_BAD_FREE 398#define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */ 399# define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \ 400 ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE(bucket) \ 401 : n_blks[bucket] ) 402#else 403# define N_BLKS(bucket) n_blks[bucket] 404#endif 405 406static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] = 407 { 408# if BUCKETS_PER_POW2==1 409 0, 0, 410 (MIN_BUC_POW2==2 ? 384 : 0), 411 224, 120, 62, 31, 16, 8, 4, 2 412# else 413 0, 0, 0, 0, 414 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */ 415 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2 416# endif 417 }; 418 419/* Shift of the first bucket with the given ordinal inside 2K chunk. */ 420#ifdef IGNORE_SMALL_BAD_FREE 421# define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \ 422 ? ((1<<LOG_OF_MIN_ARENA) \ 423 - BUCKET_SIZE(bucket) * N_BLKS(bucket)) \ 424 : blk_shift[bucket]) 425#else 426# define BLK_SHIFT(bucket) blk_shift[bucket] 427#endif 428 429static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] = 430 { 431# if BUCKETS_PER_POW2==1 432 0, 0, 433 (MIN_BUC_POW2==2 ? 512 : 0), 434 256, 128, 64, 64, /* 8 to 64 */ 435 16*sizeof(union overhead), 436 8*sizeof(union overhead), 437 4*sizeof(union overhead), 438 2*sizeof(union overhead), 439# else 440 0, 0, 0, 0, 441 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0), 442 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */ 443 16*sizeof(union overhead), 16*sizeof(union overhead), 444 8*sizeof(union overhead), 8*sizeof(union overhead), 445 4*sizeof(union overhead), 4*sizeof(union overhead), 446 2*sizeof(union overhead), 2*sizeof(union overhead), 447# endif 448 }; 449 450#else /* !PACK_MALLOC */ 451 452# define OV_MAGIC(block,bucket) (block)->ov_magic 453# define OV_INDEX(block) (block)->ov_index 454# define CHUNK_SHIFT 1 455# define MAX_PACKED -1 456#endif /* !PACK_MALLOC */ 457 458#define M_OVERHEAD (sizeof(union overhead) + RSLOP) 459 460#ifdef PACK_MALLOC 461# define MEM_OVERHEAD(bucket) \ 462 (bucket <= MAX_PACKED ? 0 : M_OVERHEAD) 463# ifdef SMALL_BUCKET_VIA_TABLE 464# define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2) 465# define START_SHIFT MAX_PACKED_POW2 466# ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */ 467# define SIZE_TABLE_MAX 80 468# else 469# define SIZE_TABLE_MAX 64 470# endif 471static char bucket_of[] = 472 { 473# ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */ 474 /* 0 to 15 in 4-byte increments. */ 475 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */ 476 6, /* 8 */ 477 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */ 478 9, 9, 10, 10, /* 24, 32 */ 479 11, 11, 11, 11, /* 48 */ 480 12, 12, 12, 12, /* 64 */ 481 13, 13, 13, 13, /* 80 */ 482 13, 13, 13, 13 /* 80 */ 483# else /* !BUCKETS_ROOT2 */ 484 /* 0 to 15 in 4-byte increments. */ 485 (sizeof(void*) > 4 ? 3 : 2), 486 3, 487 4, 4, 488 5, 5, 5, 5, 489 6, 6, 6, 6, 490 6, 6, 6, 6 491# endif /* !BUCKETS_ROOT2 */ 492 }; 493# else /* !SMALL_BUCKET_VIA_TABLE */ 494# define START_SHIFTS_BUCKET MIN_BUCKET 495# define START_SHIFT (MIN_BUC_POW2 - 1) 496# endif /* !SMALL_BUCKET_VIA_TABLE */ 497#else /* !PACK_MALLOC */ 498# define MEM_OVERHEAD(bucket) M_OVERHEAD 499# ifdef SMALL_BUCKET_VIA_TABLE 500# undef SMALL_BUCKET_VIA_TABLE 501# endif 502# define START_SHIFTS_BUCKET MIN_BUCKET 503# define START_SHIFT (MIN_BUC_POW2 - 1) 504#endif /* !PACK_MALLOC */ 505 506/* 507 * Big allocations are often of the size 2^n bytes. To make them a 508 * little bit better, make blocks of size 2^n+pagesize for big n. 509 */ 510 511#ifdef TWO_POT_OPTIMIZE 512 513# ifndef PERL_PAGESIZE 514# define PERL_PAGESIZE 4096 515# endif 516# ifndef FIRST_BIG_POW2 517# define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */ 518# endif 519# define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2) 520/* If this value or more, check against bigger blocks. */ 521# define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD) 522/* If less than this value, goes into 2^n-overhead-block. */ 523# define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD) 524 525# define POW2_OPTIMIZE_ADJUST(nbytes) \ 526 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0) 527# define POW2_OPTIMIZE_SURPLUS(bucket) \ 528 ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0) 529 530#else /* !TWO_POT_OPTIMIZE */ 531# define POW2_OPTIMIZE_ADJUST(nbytes) 532# define POW2_OPTIMIZE_SURPLUS(bucket) 0 533#endif /* !TWO_POT_OPTIMIZE */ 534 535#if defined(HAS_64K_LIMIT) && defined(PERL_CORE) 536# define BARK_64K_LIMIT(what,nbytes,size) \ 537 if (nbytes > 0xffff) { \ 538 PerlIO_printf(PerlIO_stderr(), \ 539 "%s too large: %lx\n", what, size); \ 540 my_exit(1); \ 541 } 542#else /* !HAS_64K_LIMIT || !PERL_CORE */ 543# define BARK_64K_LIMIT(what,nbytes,size) 544#endif /* !HAS_64K_LIMIT || !PERL_CORE */ 545 546#ifndef MIN_SBRK 547# define MIN_SBRK 2048 548#endif 549 550#ifndef FIRST_SBRK 551# define FIRST_SBRK (48*1024) 552#endif 553 554/* Minimal sbrk in percents of what is already alloced. */ 555#ifndef MIN_SBRK_FRAC 556# define MIN_SBRK_FRAC 3 557#endif 558 559#ifndef SBRK_ALLOW_FAILURES 560# define SBRK_ALLOW_FAILURES 3 561#endif 562 563#ifndef SBRK_FAILURE_PRICE 564# define SBRK_FAILURE_PRICE 50 565#endif 566 567#if defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE) 568 569# ifndef BIG_SIZE 570# define BIG_SIZE (1<<16) /* 64K */ 571# endif 572 573#ifdef MUTEX_INIT_CALLS_MALLOC 574# undef MUTEX_LOCK 575# define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END 576# undef MUTEX_UNLOCK 577# define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END 578#endif 579 580static char *emergency_buffer; 581static MEM_SIZE emergency_buffer_size; 582static Malloc_t emergency_sbrk(MEM_SIZE size); 583 584static Malloc_t 585emergency_sbrk(MEM_SIZE size) 586{ 587 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA; 588 589 if (size >= BIG_SIZE) { 590 /* Give the possibility to recover: */ 591 MUTEX_UNLOCK(&PL_malloc_mutex); 592 croak("Out of memory during \"large\" request for %i bytes", size); 593 } 594 595 if (emergency_buffer_size >= rsize) { 596 char *old = emergency_buffer; 597 598 emergency_buffer_size -= rsize; 599 emergency_buffer += rsize; 600 return old; 601 } else { 602 dTHR; 603 /* First offense, give a possibility to recover by dieing. */ 604 /* No malloc involved here: */ 605 GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0); 606 SV *sv; 607 char *pv; 608 int have = 0; 609 STRLEN n_a; 610 611 if (emergency_buffer_size) { 612 add_to_chain(emergency_buffer, emergency_buffer_size, 0); 613 emergency_buffer_size = 0; 614 emergency_buffer = Nullch; 615 have = 1; 616 } 617 if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0); 618 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv) 619 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD)) { 620 if (have) 621 goto do_croak; 622 return (char *)-1; /* Now die die die... */ 623 } 624 /* Got it, now detach SvPV: */ 625 pv = SvPV(sv, n_a); 626 /* Check alignment: */ 627 if (((UV)(pv - sizeof(union overhead))) & ((1<<LOG_OF_MIN_ARENA) - 1)) { 628 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n"); 629 return (char *)-1; /* die die die */ 630 } 631 632 emergency_buffer = pv - sizeof(union overhead); 633 emergency_buffer_size = malloced_size(pv) + M_OVERHEAD; 634 SvPOK_off(sv); 635 SvPVX(sv) = Nullch; 636 SvCUR(sv) = SvLEN(sv) = 0; 637 } 638 do_croak: 639 MUTEX_UNLOCK(&PL_malloc_mutex); 640 croak("Out of memory during request for %i bytes", size); 641} 642 643#else /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */ 644# define emergency_sbrk(size) -1 645#endif /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */ 646 647/* 648 * nextf[i] is the pointer to the next free block of size 2^i. The 649 * smallest allocatable block is 8 bytes. The overhead information 650 * precedes the data area returned to the user. 651 */ 652#define NBUCKETS (32*BUCKETS_PER_POW2 + 1) 653static union overhead *nextf[NBUCKETS]; 654 655#ifdef USE_PERL_SBRK 656#define sbrk(a) Perl_sbrk(a) 657Malloc_t Perl_sbrk _((int size)); 658#else 659#ifdef DONT_DECLARE_STD 660#ifdef I_UNISTD 661#include <unistd.h> 662#endif 663#else 664extern Malloc_t sbrk(int); 665#endif 666#endif 667 668#ifdef DEBUGGING_MSTATS 669/* 670 * nmalloc[i] is the difference between the number of mallocs and frees 671 * for a given block size. 672 */ 673static u_int nmalloc[NBUCKETS]; 674static u_int sbrk_slack; 675static u_int start_slack; 676#endif 677 678static u_int goodsbrk; 679 680#ifdef DEBUGGING 681#undef ASSERT 682#define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p)); else 683static void 684botch(char *diag, char *s) 685{ 686 PerlIO_printf(PerlIO_stderr(), "assertion botched (%s?): %s\n", diag, s); 687 PerlProc_abort(); 688} 689#else 690#define ASSERT(p, diag) 691#endif 692 693Malloc_t 694malloc(register size_t nbytes) 695{ 696 register union overhead *p; 697 register int bucket; 698 register MEM_SIZE shiftr; 699 700#if defined(DEBUGGING) || defined(RCHECK) 701 MEM_SIZE size = nbytes; 702#endif 703 704 BARK_64K_LIMIT("Allocation",nbytes,nbytes); 705#ifdef DEBUGGING 706 if ((long)nbytes < 0) 707 croak("%s", "panic: malloc"); 708#endif 709 710 MUTEX_LOCK(&PL_malloc_mutex); 711 /* 712 * Convert amount of memory requested into 713 * closest block size stored in hash buckets 714 * which satisfies request. Account for 715 * space used per block for accounting. 716 */ 717#ifdef PACK_MALLOC 718# ifdef SMALL_BUCKET_VIA_TABLE 719 if (nbytes == 0) 720 bucket = MIN_BUCKET; 721 else if (nbytes <= SIZE_TABLE_MAX) { 722 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT]; 723 } else 724# else 725 if (nbytes == 0) 726 nbytes = 1; 727 if (nbytes <= MAX_POW2_ALGO) goto do_shifts; 728 else 729# endif 730#endif 731 { 732 POW2_OPTIMIZE_ADJUST(nbytes); 733 nbytes += M_OVERHEAD; 734 nbytes = (nbytes + 3) &~ 3; 735 do_shifts: 736 shiftr = (nbytes - 1) >> START_SHIFT; 737 bucket = START_SHIFTS_BUCKET; 738 /* apart from this loop, this is O(1) */ 739 while (shiftr >>= 1) 740 bucket += BUCKETS_PER_POW2; 741 } 742 /* 743 * If nothing in hash bucket right now, 744 * request more memory from the system. 745 */ 746 if (nextf[bucket] == NULL) 747 morecore(bucket); 748 if ((p = nextf[bucket]) == NULL) { 749 MUTEX_UNLOCK(&PL_malloc_mutex); 750#ifdef PERL_CORE 751 if (!PL_nomemok) { 752 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n"); 753 my_exit(1); 754 } 755#else 756 return (NULL); 757#endif 758 } 759 760 DEBUG_m(PerlIO_printf(Perl_debug_log, 761 "0x%lx: (%05lu) malloc %ld bytes\n", 762 (unsigned long)(p+1), (unsigned long)(PL_an++), 763 (long)size)); 764 765 /* remove from linked list */ 766#if defined(RCHECK) 767 if (((UV)p) & (MEM_ALIGNBYTES - 1)) 768 PerlIO_printf(PerlIO_stderr(), "Corrupt malloc ptr 0x%lx at 0x%lx\n", 769 (unsigned long)*((int*)p),(unsigned long)p); 770#endif 771 nextf[bucket] = p->ov_next; 772#ifdef IGNORE_SMALL_BAD_FREE 773 if (bucket >= FIRST_BUCKET_WITH_CHECK) 774#endif 775 OV_MAGIC(p, bucket) = MAGIC; 776#ifndef PACK_MALLOC 777 OV_INDEX(p) = bucket; 778#endif 779#ifdef RCHECK 780 /* 781 * Record allocated size of block and 782 * bound space with magic numbers. 783 */ 784 p->ov_rmagic = RMAGIC; 785 if (bucket <= MAX_SHORT_BUCKET) { 786 int i; 787 788 nbytes = size + M_OVERHEAD; 789 p->ov_size = nbytes - 1; 790 if ((i = nbytes & 3)) { 791 i = 4 - i; 792 while (i--) 793 *((char *)((caddr_t)p + nbytes - RSLOP + i)) = RMAGIC_C; 794 } 795 nbytes = (nbytes + 3) &~ 3; 796 *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC; 797 } 798#endif 799 MUTEX_UNLOCK(&PL_malloc_mutex); 800 return ((Malloc_t)(p + CHUNK_SHIFT)); 801} 802 803static char *last_sbrk_top; 804static char *last_op; /* This arena can be easily extended. */ 805static int sbrked_remains; 806static int sbrk_good = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE; 807 808#ifdef DEBUGGING_MSTATS 809static int sbrks; 810#endif 811 812struct chunk_chain_s { 813 struct chunk_chain_s *next; 814 MEM_SIZE size; 815}; 816static struct chunk_chain_s *chunk_chain; 817static int n_chunks; 818static char max_bucket; 819 820/* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */ 821static void * 822get_from_chain(MEM_SIZE size) 823{ 824 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain; 825 struct chunk_chain_s **oldgoodp = NULL; 826 long min_remain = LONG_MAX; 827 828 while (elt) { 829 if (elt->size >= size) { 830 long remains = elt->size - size; 831 if (remains >= 0 && remains < min_remain) { 832 oldgoodp = oldp; 833 min_remain = remains; 834 } 835 if (remains == 0) { 836 break; 837 } 838 } 839 oldp = &( elt->next ); 840 elt = elt->next; 841 } 842 if (!oldgoodp) return NULL; 843 if (min_remain) { 844 void *ret = *oldgoodp; 845 struct chunk_chain_s *next = (*oldgoodp)->next; 846 847 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size); 848 (*oldgoodp)->size = min_remain; 849 (*oldgoodp)->next = next; 850 return ret; 851 } else { 852 void *ret = *oldgoodp; 853 *oldgoodp = (*oldgoodp)->next; 854 n_chunks--; 855 return ret; 856 } 857} 858 859static void 860add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip) 861{ 862 struct chunk_chain_s *next = chunk_chain; 863 char *cp = (char*)p; 864 865 cp += chip; 866 chunk_chain = (struct chunk_chain_s *)cp; 867 chunk_chain->size = size - chip; 868 chunk_chain->next = next; 869 n_chunks++; 870} 871 872static void * 873get_from_bigger_buckets(int bucket, MEM_SIZE size) 874{ 875 int price = 1; 876 static int bucketprice[NBUCKETS]; 877 while (bucket <= max_bucket) { 878 /* We postpone stealing from bigger buckets until we want it 879 often enough. */ 880 if (nextf[bucket] && bucketprice[bucket]++ >= price) { 881 /* Steal it! */ 882 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT); 883 bucketprice[bucket] = 0; 884 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) { 885 last_op = NULL; /* Disable optimization */ 886 } 887 nextf[bucket] = nextf[bucket]->ov_next; 888#ifdef DEBUGGING_MSTATS 889 nmalloc[bucket]--; 890 start_slack -= M_OVERHEAD; 891#endif 892 add_to_chain(ret, (BUCKET_SIZE(bucket) + 893 POW2_OPTIMIZE_SURPLUS(bucket)), 894 size); 895 return ret; 896 } 897 bucket++; 898 } 899 return NULL; 900} 901 902static union overhead * 903getpages(int needed, int *nblksp, int bucket) 904{ 905 /* Need to do (possibly expensive) system call. Try to 906 optimize it for rare calling. */ 907 MEM_SIZE require = needed - sbrked_remains; 908 char *cp; 909 union overhead *ovp; 910 int slack = 0; 911 912 if (sbrk_good > 0) { 913 if (!last_sbrk_top && require < FIRST_SBRK) 914 require = FIRST_SBRK; 915 else if (require < MIN_SBRK) require = MIN_SBRK; 916 917 if (require < goodsbrk * MIN_SBRK_FRAC / 100) 918 require = goodsbrk * MIN_SBRK_FRAC / 100; 919 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK; 920 } else { 921 require = needed; 922 last_sbrk_top = 0; 923 sbrked_remains = 0; 924 } 925 926 DEBUG_m(PerlIO_printf(Perl_debug_log, 927 "sbrk(%ld) for %ld-byte-long arena\n", 928 (long)require, (long) needed)); 929 cp = (char *)sbrk(require); 930#ifdef DEBUGGING_MSTATS 931 sbrks++; 932#endif 933 if (cp == last_sbrk_top) { 934 /* Common case, anything is fine. */ 935 sbrk_good++; 936 ovp = (union overhead *) (cp - sbrked_remains); 937 sbrked_remains = require - (needed - sbrked_remains); 938 } else if (cp == (char *)-1) { /* no more room! */ 939 ovp = (union overhead *)emergency_sbrk(needed); 940 if (ovp == (union overhead *)-1) 941 return 0; 942 return ovp; 943 } else { /* Non-continuous or first sbrk(). */ 944 long add = sbrked_remains; 945 char *newcp; 946 947 if (sbrked_remains) { /* Put rest into chain, we 948 cannot use it right now. */ 949 add_to_chain((void*)(last_sbrk_top - sbrked_remains), 950 sbrked_remains, 0); 951 } 952 953 /* Second, check alignment. */ 954 slack = 0; 955 956#if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */ 957# ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */ 958 959 /* CHUNK_SHIFT is 1 for PACK_MALLOC, 0 otherwise. */ 960 if ((UV)cp & (0x7FF >> CHUNK_SHIFT)) { /* Not aligned. */ 961 slack = (0x800 >> CHUNK_SHIFT) 962 - ((UV)cp & (0x7FF >> CHUNK_SHIFT)); 963 add += slack; 964 } 965# endif 966#endif /* !atarist && !MINT */ 967 968 if (add) { 969 DEBUG_m(PerlIO_printf(Perl_debug_log, 970 "sbrk(%ld) to fix non-continuous/off-page sbrk:\n\t%ld for alignement,\t%ld were assumed to come from the tail of the previous sbrk\n", 971 (long)add, (long) slack, 972 (long) sbrked_remains)); 973 newcp = (char *)sbrk(add); 974#if defined(DEBUGGING_MSTATS) 975 sbrks++; 976 sbrk_slack += add; 977#endif 978 if (newcp != cp + require) { 979 /* Too bad: even rounding sbrk() is not continuous.*/ 980 DEBUG_m(PerlIO_printf(Perl_debug_log, 981 "failed to fix bad sbrk()\n")); 982#ifdef PACK_MALLOC 983 if (slack) { 984 MUTEX_UNLOCK(&PL_malloc_mutex); 985 croak("%s", "panic: Off-page sbrk"); 986 } 987#endif 988 if (sbrked_remains) { 989 /* Try again. */ 990#if defined(DEBUGGING_MSTATS) 991 sbrk_slack += require; 992#endif 993 require = needed; 994 DEBUG_m(PerlIO_printf(Perl_debug_log, 995 "straight sbrk(%ld)\n", 996 (long)require)); 997 cp = (char *)sbrk(require); 998#ifdef DEBUGGING_MSTATS 999 sbrks++; 1000#endif 1001 if (cp == (char *)-1) 1002 return 0; 1003 } 1004 sbrk_good = -1; /* Disable optimization! 1005 Continue with not-aligned... */ 1006 } else { 1007 cp += slack; 1008 require += sbrked_remains; 1009 } 1010 } 1011 1012 if (last_sbrk_top) { 1013 sbrk_good -= SBRK_FAILURE_PRICE; 1014 } 1015 1016 ovp = (union overhead *) cp; 1017 /* 1018 * Round up to minimum allocation size boundary 1019 * and deduct from block count to reflect. 1020 */ 1021 1022#ifndef I286 /* Again, this should always be ok on an 80286 */ 1023 if ((UV)ovp & 7) { 1024 ovp = (union overhead *)(((UV)ovp + 8) & ~7); 1025 DEBUG_m(PerlIO_printf(Perl_debug_log, 1026 "fixing sbrk(): %d bytes off machine alignement\n", 1027 (int)((UV)ovp & 7))); 1028 (*nblksp)--; 1029# if defined(DEBUGGING_MSTATS) 1030 /* This is only approx. if TWO_POT_OPTIMIZE: */ 1031 sbrk_slack += (1 << bucket); 1032# endif 1033 } 1034#endif 1035 sbrked_remains = require - needed; 1036 } 1037 last_sbrk_top = cp + require; 1038 last_op = (char*) cp; 1039#ifdef DEBUGGING_MSTATS 1040 goodsbrk += require; 1041#endif 1042 return ovp; 1043} 1044 1045static int 1046getpages_adjacent(int require) 1047{ 1048 if (require <= sbrked_remains) { 1049 sbrked_remains -= require; 1050 } else { 1051 char *cp; 1052 1053 require -= sbrked_remains; 1054 /* We do not try to optimize sbrks here, we go for place. */ 1055 cp = (char*) sbrk(require); 1056#ifdef DEBUGGING_MSTATS 1057 sbrks++; 1058 goodsbrk += require; 1059#endif 1060 if (cp == last_sbrk_top) { 1061 sbrked_remains = 0; 1062 last_sbrk_top = cp + require; 1063 } else { 1064 if (cp == (char*)-1) { /* Out of memory */ 1065#ifdef DEBUGGING_MSTATS 1066 goodsbrk -= require; 1067#endif 1068 return 0; 1069 } 1070 /* Report the failure: */ 1071 if (sbrked_remains) 1072 add_to_chain((void*)(last_sbrk_top - sbrked_remains), 1073 sbrked_remains, 0); 1074 add_to_chain((void*)cp, require, 0); 1075 sbrk_good -= SBRK_FAILURE_PRICE; 1076 sbrked_remains = 0; 1077 last_sbrk_top = 0; 1078 last_op = 0; 1079 return 0; 1080 } 1081 } 1082 1083 return 1; 1084} 1085 1086/* 1087 * Allocate more memory to the indicated bucket. 1088 */ 1089static void 1090morecore(register int bucket) 1091{ 1092 register union overhead *ovp; 1093 register int rnu; /* 2^rnu bytes will be requested */ 1094 int nblks; /* become nblks blocks of the desired size */ 1095 register MEM_SIZE siz, needed; 1096 1097 if (nextf[bucket]) 1098 return; 1099 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) { 1100 MUTEX_UNLOCK(&PL_malloc_mutex); 1101 croak("%s", "Out of memory during ridiculously large request"); 1102 } 1103 if (bucket > max_bucket) 1104 max_bucket = bucket; 1105 1106 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT)) 1107 ? LOG_OF_MIN_ARENA 1108 : (bucket >> BUCKET_POW2_SHIFT) ); 1109 /* This may be overwritten later: */ 1110 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */ 1111 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket); 1112 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */ 1113 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT; 1114 nextf[rnu << BUCKET_POW2_SHIFT] 1115 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next; 1116#ifdef DEBUGGING_MSTATS 1117 nmalloc[rnu << BUCKET_POW2_SHIFT]--; 1118 start_slack -= M_OVERHEAD; 1119#endif 1120 DEBUG_m(PerlIO_printf(Perl_debug_log, 1121 "stealing %ld bytes from %ld arena\n", 1122 (long) needed, (long) rnu << BUCKET_POW2_SHIFT)); 1123 } else if (chunk_chain 1124 && (ovp = (union overhead*) get_from_chain(needed))) { 1125 DEBUG_m(PerlIO_printf(Perl_debug_log, 1126 "stealing %ld bytes from chain\n", 1127 (long) needed)); 1128 } else if ( (ovp = (union overhead*) 1129 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1, 1130 needed)) ) { 1131 DEBUG_m(PerlIO_printf(Perl_debug_log, 1132 "stealing %ld bytes from bigger buckets\n", 1133 (long) needed)); 1134 } else if (needed <= sbrked_remains) { 1135 ovp = (union overhead *)(last_sbrk_top - sbrked_remains); 1136 sbrked_remains -= needed; 1137 last_op = (char*)ovp; 1138 } else 1139 ovp = getpages(needed, &nblks, bucket); 1140 1141 if (!ovp) 1142 return; 1143 1144 /* 1145 * Add new memory allocated to that on 1146 * free list for this hash bucket. 1147 */ 1148 siz = BUCKET_SIZE(bucket); 1149#ifdef PACK_MALLOC 1150 *(u_char*)ovp = bucket; /* Fill index. */ 1151 if (bucket <= MAX_PACKED) { 1152 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket)); 1153 nblks = N_BLKS(bucket); 1154# ifdef DEBUGGING_MSTATS 1155 start_slack += BLK_SHIFT(bucket); 1156# endif 1157 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) { 1158 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket)); 1159 siz -= sizeof(union overhead); 1160 } else ovp++; /* One chunk per block. */ 1161#endif /* PACK_MALLOC */ 1162 nextf[bucket] = ovp; 1163#ifdef DEBUGGING_MSTATS 1164 nmalloc[bucket] += nblks; 1165 if (bucket > MAX_PACKED) { 1166 start_slack += M_OVERHEAD * nblks; 1167 } 1168#endif 1169 while (--nblks > 0) { 1170 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz); 1171 ovp = (union overhead *)((caddr_t)ovp + siz); 1172 } 1173 /* Not all sbrks return zeroed memory.*/ 1174 ovp->ov_next = (union overhead *)NULL; 1175#ifdef PACK_MALLOC 1176 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */ 1177 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next; 1178 nextf[7*BUCKETS_PER_POW2] = 1179 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2] 1180 - sizeof(union overhead)); 1181 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op; 1182 } 1183#endif /* !PACK_MALLOC */ 1184} 1185 1186Free_t 1187free(void *mp) 1188{ 1189 register MEM_SIZE size; 1190 register union overhead *ovp; 1191 char *cp = (char*)mp; 1192#ifdef PACK_MALLOC 1193 u_char bucket; 1194#endif 1195 1196 DEBUG_m(PerlIO_printf(Perl_debug_log, 1197 "0x%lx: (%05lu) free\n", 1198 (unsigned long)cp, (unsigned long)(PL_an++))); 1199 1200 if (cp == NULL) 1201 return; 1202 ovp = (union overhead *)((caddr_t)cp 1203 - sizeof (union overhead) * CHUNK_SHIFT); 1204#ifdef PACK_MALLOC 1205 bucket = OV_INDEX(ovp); 1206#endif 1207#ifdef IGNORE_SMALL_BAD_FREE 1208 if ((bucket >= FIRST_BUCKET_WITH_CHECK) 1209 && (OV_MAGIC(ovp, bucket) != MAGIC)) 1210#else 1211 if (OV_MAGIC(ovp, bucket) != MAGIC) 1212#endif 1213 { 1214 static int bad_free_warn = -1; 1215 if (bad_free_warn == -1) { 1216 char *pbf = PerlEnv_getenv("PERL_BADFREE"); 1217 bad_free_warn = (pbf) ? atoi(pbf) : 1; 1218 } 1219 if (!bad_free_warn) 1220 return; 1221#ifdef RCHECK 1222 warn("%s free() ignored", 1223 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad"); 1224#else 1225 warn("%s", "Bad free() ignored"); 1226#endif 1227 return; /* sanity */ 1228 } 1229 MUTEX_LOCK(&PL_malloc_mutex); 1230#ifdef RCHECK 1231 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite"); 1232 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) { 1233 int i; 1234 MEM_SIZE nbytes = ovp->ov_size + 1; 1235 1236 if ((i = nbytes & 3)) { 1237 i = 4 - i; 1238 while (i--) { 1239 ASSERT(*((char *)((caddr_t)ovp + nbytes - RSLOP + i)) 1240 == RMAGIC_C, "chunk's tail overwrite"); 1241 } 1242 } 1243 nbytes = (nbytes + 3) &~ 3; 1244 ASSERT(*(u_int *)((caddr_t)ovp + nbytes - RSLOP) == RMAGIC, "chunk's tail overwrite"); 1245 } 1246 ovp->ov_rmagic = RMAGIC - 1; 1247#endif 1248 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite"); 1249 size = OV_INDEX(ovp); 1250 ovp->ov_next = nextf[size]; 1251 nextf[size] = ovp; 1252 MUTEX_UNLOCK(&PL_malloc_mutex); 1253} 1254 1255/* 1256 * When a program attempts "storage compaction" as mentioned in the 1257 * old malloc man page, it realloc's an already freed block. Usually 1258 * this is the last block it freed; occasionally it might be farther 1259 * back. We have to search all the free lists for the block in order 1260 * to determine its bucket: 1st we make one pass thru the lists 1261 * checking only the first block in each; if that fails we search 1262 * ``reall_srchlen'' blocks in each list for a match (the variable 1263 * is extern so the caller can modify it). If that fails we just copy 1264 * however many bytes was given to realloc() and hope it's not huge. 1265 */ 1266int reall_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */ 1267 1268Malloc_t 1269realloc(void *mp, size_t nbytes) 1270{ 1271 register MEM_SIZE onb; 1272 union overhead *ovp; 1273 char *res; 1274 int prev_bucket; 1275 register int bucket; 1276 int was_alloced = 0, incr; 1277 char *cp = (char*)mp; 1278 1279#if defined(DEBUGGING) || !defined(PERL_CORE) 1280 MEM_SIZE size = nbytes; 1281 1282 if ((long)nbytes < 0) 1283 croak("%s", "panic: realloc"); 1284#endif 1285 1286 BARK_64K_LIMIT("Reallocation",nbytes,size); 1287 if (!cp) 1288 return malloc(nbytes); 1289 1290 MUTEX_LOCK(&PL_malloc_mutex); 1291 ovp = (union overhead *)((caddr_t)cp 1292 - sizeof (union overhead) * CHUNK_SHIFT); 1293 bucket = OV_INDEX(ovp); 1294#ifdef IGNORE_SMALL_BAD_FREE 1295 if ((bucket < FIRST_BUCKET_WITH_CHECK) 1296 || (OV_MAGIC(ovp, bucket) == MAGIC)) 1297#else 1298 if (OV_MAGIC(ovp, bucket) == MAGIC) 1299#endif 1300 { 1301 was_alloced = 1; 1302 } else { 1303 /* 1304 * Already free, doing "compaction". 1305 * 1306 * Search for the old block of memory on the 1307 * free list. First, check the most common 1308 * case (last element free'd), then (this failing) 1309 * the last ``reall_srchlen'' items free'd. 1310 * If all lookups fail, then assume the size of 1311 * the memory block being realloc'd is the 1312 * smallest possible. 1313 */ 1314 if ((bucket = findbucket(ovp, 1)) < 0 && 1315 (bucket = findbucket(ovp, reall_srchlen)) < 0) 1316 bucket = 0; 1317 } 1318 onb = BUCKET_SIZE_REAL(bucket); 1319 /* 1320 * avoid the copy if same size block. 1321 * We are not agressive with boundary cases. Note that it might 1322 * (for a small number of cases) give false negative if 1323 * both new size and old one are in the bucket for 1324 * FIRST_BIG_POW2, but the new one is near the lower end. 1325 * 1326 * We do not try to go to 1.5 times smaller bucket so far. 1327 */ 1328 if (nbytes > onb) incr = 1; 1329 else { 1330#ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING 1331 if ( /* This is a little bit pessimal if PACK_MALLOC: */ 1332 nbytes > ( (onb >> 1) - M_OVERHEAD ) 1333# ifdef TWO_POT_OPTIMIZE 1334 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND ) 1335# endif 1336 ) 1337#else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */ 1338 prev_bucket = ( (bucket > MAX_PACKED + 1) 1339 ? bucket - BUCKETS_PER_POW2 1340 : bucket - 1); 1341 if (nbytes > BUCKET_SIZE_REAL(prev_bucket)) 1342#endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */ 1343 incr = 0; 1344 else incr = -1; 1345 } 1346 if (!was_alloced 1347#ifdef STRESS_REALLOC 1348 || 1 /* always do it the hard way */ 1349#endif 1350 ) goto hard_way; 1351 else if (incr == 0) { 1352 inplace_label: 1353#ifdef RCHECK 1354 /* 1355 * Record new allocated size of block and 1356 * bound space with magic numbers. 1357 */ 1358 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) { 1359 int i, nb = ovp->ov_size + 1; 1360 1361 if ((i = nb & 3)) { 1362 i = 4 - i; 1363 while (i--) { 1364 ASSERT(*((char *)((caddr_t)ovp + nb - RSLOP + i)) == RMAGIC_C, "chunk's tail overwrite"); 1365 } 1366 } 1367 nb = (nb + 3) &~ 3; 1368 ASSERT(*(u_int *)((caddr_t)ovp + nb - RSLOP) == RMAGIC, "chunk's tail overwrite"); 1369 /* 1370 * Convert amount of memory requested into 1371 * closest block size stored in hash buckets 1372 * which satisfies request. Account for 1373 * space used per block for accounting. 1374 */ 1375 nbytes += M_OVERHEAD; 1376 ovp->ov_size = nbytes - 1; 1377 if ((i = nbytes & 3)) { 1378 i = 4 - i; 1379 while (i--) 1380 *((char *)((caddr_t)ovp + nbytes - RSLOP + i)) 1381 = RMAGIC_C; 1382 } 1383 nbytes = (nbytes + 3) &~ 3; 1384 *((u_int *)((caddr_t)ovp + nbytes - RSLOP)) = RMAGIC; 1385 } 1386#endif 1387 res = cp; 1388 MUTEX_UNLOCK(&PL_malloc_mutex); 1389 DEBUG_m(PerlIO_printf(Perl_debug_log, 1390 "0x%lx: (%05lu) realloc %ld bytes inplace\n", 1391 (unsigned long)res,(unsigned long)(PL_an++), 1392 (long)size)); 1393 } else if (incr == 1 && (cp - M_OVERHEAD == last_op) 1394 && (onb > (1 << LOG_OF_MIN_ARENA))) { 1395 MEM_SIZE require, newarena = nbytes, pow; 1396 int shiftr; 1397 1398 POW2_OPTIMIZE_ADJUST(newarena); 1399 newarena = newarena + M_OVERHEAD; 1400 /* newarena = (newarena + 3) &~ 3; */ 1401 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA; 1402 pow = LOG_OF_MIN_ARENA + 1; 1403 /* apart from this loop, this is O(1) */ 1404 while (shiftr >>= 1) 1405 pow++; 1406 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2); 1407 require = newarena - onb - M_OVERHEAD; 1408 1409 if (getpages_adjacent(require)) { 1410#ifdef DEBUGGING_MSTATS 1411 nmalloc[bucket]--; 1412 nmalloc[pow * BUCKETS_PER_POW2]++; 1413#endif 1414 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */ 1415 goto inplace_label; 1416 } else 1417 goto hard_way; 1418 } else { 1419 hard_way: 1420 MUTEX_UNLOCK(&PL_malloc_mutex); 1421 DEBUG_m(PerlIO_printf(Perl_debug_log, 1422 "0x%lx: (%05lu) realloc %ld bytes the hard way\n", 1423 (unsigned long)cp,(unsigned long)(PL_an++), 1424 (long)size)); 1425 if ((res = (char*)malloc(nbytes)) == NULL) 1426 return (NULL); 1427 if (cp != res) /* common optimization */ 1428 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char); 1429 if (was_alloced) 1430 free(cp); 1431 } 1432 return ((Malloc_t)res); 1433} 1434 1435/* 1436 * Search ``srchlen'' elements of each free list for a block whose 1437 * header starts at ``freep''. If srchlen is -1 search the whole list. 1438 * Return bucket number, or -1 if not found. 1439 */ 1440static int 1441findbucket(union overhead *freep, int srchlen) 1442{ 1443 register union overhead *p; 1444 register int i, j; 1445 1446 for (i = 0; i < NBUCKETS; i++) { 1447 j = 0; 1448 for (p = nextf[i]; p && j != srchlen; p = p->ov_next) { 1449 if (p == freep) 1450 return (i); 1451 j++; 1452 } 1453 } 1454 return (-1); 1455} 1456 1457Malloc_t 1458calloc(register size_t elements, register size_t size) 1459{ 1460 long sz = elements * size; 1461 Malloc_t p = malloc(sz); 1462 1463 if (p) { 1464 memset((void*)p, 0, sz); 1465 } 1466 return p; 1467} 1468 1469MEM_SIZE 1470malloced_size(void *p) 1471{ 1472 union overhead *ovp = (union overhead *) 1473 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT); 1474 int bucket = OV_INDEX(ovp); 1475#ifdef RCHECK 1476 /* The caller wants to have a complete control over the chunk, 1477 disable the memory checking inside the chunk. */ 1478 if (bucket <= MAX_SHORT_BUCKET) { 1479 MEM_SIZE size = BUCKET_SIZE_REAL(bucket); 1480 ovp->ov_size = size + M_OVERHEAD - 1; 1481 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RSLOP)) = RMAGIC; 1482 } 1483#endif 1484 return BUCKET_SIZE_REAL(bucket); 1485} 1486 1487#ifdef DEBUGGING_MSTATS 1488 1489# ifdef BUCKETS_ROOT2 1490# define MIN_EVEN_REPORT 6 1491# else 1492# define MIN_EVEN_REPORT MIN_BUCKET 1493# endif 1494/* 1495 * mstats - print out statistics about malloc 1496 * 1497 * Prints two lines of numbers, one showing the length of the free list 1498 * for each size category, the second showing the number of mallocs - 1499 * frees for each size category. 1500 */ 1501void 1502dump_mstats(char *s) 1503{ 1504 register int i, j; 1505 register union overhead *p; 1506 int topbucket=0, topbucket_ev=0, topbucket_odd=0, totfree=0, total=0; 1507 u_int nfree[NBUCKETS]; 1508 int total_chain = 0; 1509 struct chunk_chain_s* nextchain = chunk_chain; 1510 1511 for (i = MIN_BUCKET ; i < NBUCKETS; i++) { 1512 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) 1513 ; 1514 nfree[i] = j; 1515 totfree += nfree[i] * BUCKET_SIZE_REAL(i); 1516 total += nmalloc[i] * BUCKET_SIZE_REAL(i); 1517 if (nmalloc[i]) { 1518 i % 2 ? (topbucket_odd = i) : (topbucket_ev = i); 1519 topbucket = i; 1520 } 1521 } 1522 if (s) 1523 PerlIO_printf(PerlIO_stderr(), 1524 "Memory allocation statistics %s (buckets %ld(%ld)..%ld(%ld)\n", 1525 s, 1526 (long)BUCKET_SIZE_REAL(MIN_BUCKET), 1527 (long)BUCKET_SIZE(MIN_BUCKET), 1528 (long)BUCKET_SIZE_REAL(topbucket), (long)BUCKET_SIZE(topbucket)); 1529 PerlIO_printf(PerlIO_stderr(), "%8d free:", totfree); 1530 for (i = MIN_EVEN_REPORT; i <= topbucket; i += BUCKETS_PER_POW2) { 1531 PerlIO_printf(PerlIO_stderr(), 1532 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) 1533 ? " %5d" 1534 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")), 1535 nfree[i]); 1536 } 1537#ifdef BUCKETS_ROOT2 1538 PerlIO_printf(PerlIO_stderr(), "\n\t "); 1539 for (i = MIN_BUCKET + 1; i <= topbucket_odd; i += BUCKETS_PER_POW2) { 1540 PerlIO_printf(PerlIO_stderr(), 1541 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) 1542 ? " %5d" 1543 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")), 1544 nfree[i]); 1545 } 1546#endif 1547 PerlIO_printf(PerlIO_stderr(), "\n%8d used:", total - totfree); 1548 for (i = MIN_EVEN_REPORT; i <= topbucket; i += BUCKETS_PER_POW2) { 1549 PerlIO_printf(PerlIO_stderr(), 1550 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) 1551 ? " %5d" 1552 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")), 1553 nmalloc[i] - nfree[i]); 1554 } 1555#ifdef BUCKETS_ROOT2 1556 PerlIO_printf(PerlIO_stderr(), "\n\t "); 1557 for (i = MIN_BUCKET + 1; i <= topbucket_odd; i += BUCKETS_PER_POW2) { 1558 PerlIO_printf(PerlIO_stderr(), 1559 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) 1560 ? " %5d" 1561 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")), 1562 nmalloc[i] - nfree[i]); 1563 } 1564#endif 1565 while (nextchain) { 1566 total_chain += nextchain->size; 1567 nextchain = nextchain->next; 1568 } 1569 PerlIO_printf(PerlIO_stderr(), "\nTotal sbrk(): %d/%d:%d. Odd ends: pad+heads+chain+tail: %d+%d+%d+%d.\n", 1570 goodsbrk + sbrk_slack, sbrks, sbrk_good, sbrk_slack, 1571 start_slack, total_chain, sbrked_remains); 1572} 1573#else 1574void 1575dump_mstats(char *s) 1576{ 1577} 1578#endif 1579#endif /* lint */ 1580 1581 1582#ifdef USE_PERL_SBRK 1583 1584# if defined(__MACHTEN_PPC__) || defined(__NeXT__) 1585# define PERL_SBRK_VIA_MALLOC 1586/* 1587 * MachTen's malloc() returns a buffer aligned on a two-byte boundary. 1588 * While this is adequate, it may slow down access to longer data 1589 * types by forcing multiple memory accesses. It also causes 1590 * complaints when RCHECK is in force. So we allocate six bytes 1591 * more than we need to, and return an address rounded up to an 1592 * eight-byte boundary. 1593 * 1594 * 980701 Dominic Dunlop <domo@computer.org> 1595 */ 1596# define SYSTEM_ALLOC(a) ((void *)(((unsigned)malloc((a)+6)+6)&~7)) 1597# endif 1598 1599# ifdef PERL_SBRK_VIA_MALLOC 1600# if defined(HIDEMYMALLOC) || defined(EMBEDMYMALLOC) 1601# undef malloc /* Expose names that */ 1602# undef calloc /* HIDEMYMALLOC hides */ 1603# undef realloc 1604# undef free 1605# else 1606# include "Error: -DPERL_SBRK_VIA_MALLOC needs -D(HIDE|EMBED)MYMALLOC" 1607# endif 1608 1609/* it may seem schizophrenic to use perl's malloc and let it call system */ 1610/* malloc, the reason for that is only the 3.2 version of the OS that had */ 1611/* frequent core dumps within nxzonefreenolock. This sbrk routine put an */ 1612/* end to the cores */ 1613 1614# ifndef SYSTEM_ALLOC 1615# define SYSTEM_ALLOC(a) malloc(a) 1616# endif 1617 1618# endif /* PERL_SBRK_VIA_MALLOC */ 1619 1620static IV Perl_sbrk_oldchunk; 1621static long Perl_sbrk_oldsize; 1622 1623# define PERLSBRK_32_K (1<<15) 1624# define PERLSBRK_64_K (1<<16) 1625 1626Malloc_t 1627Perl_sbrk(int size) 1628{ 1629 IV got; 1630 int small, reqsize; 1631 1632 if (!size) return 0; 1633#ifdef PERL_CORE 1634 reqsize = size; /* just for the DEBUG_m statement */ 1635#endif 1636#ifdef PACK_MALLOC 1637 size = (size + 0x7ff) & ~0x7ff; 1638#endif 1639 if (size <= Perl_sbrk_oldsize) { 1640 got = Perl_sbrk_oldchunk; 1641 Perl_sbrk_oldchunk += size; 1642 Perl_sbrk_oldsize -= size; 1643 } else { 1644 if (size >= PERLSBRK_32_K) { 1645 small = 0; 1646 } else { 1647 size = PERLSBRK_64_K; 1648 small = 1; 1649 } 1650 got = (IV)SYSTEM_ALLOC(size); 1651#ifdef PACK_MALLOC 1652 got = (got + 0x7ff) & ~0x7ff; 1653#endif 1654 if (small) { 1655 /* Chunk is small, register the rest for future allocs. */ 1656 Perl_sbrk_oldchunk = got + reqsize; 1657 Perl_sbrk_oldsize = size - reqsize; 1658 } 1659 } 1660 1661 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%lx\n", 1662 size, reqsize, Perl_sbrk_oldsize, got)); 1663 1664 return (void *)got; 1665} 1666 1667#endif /* ! defined USE_PERL_SBRK */ 1668