1 /* malloc.c 2 * 3 */ 4 5 /* 6 Here are some notes on configuring Perl's malloc. (For non-perl 7 usage see below.) 8 9 There are two macros which serve as bulk disablers of advanced 10 features of this malloc: NO_FANCY_MALLOC, PLAIN_MALLOC (undef by 11 default). Look in the list of default values below to understand 12 their exact effect. Defining NO_FANCY_MALLOC returns malloc.c to the 13 state of the malloc in Perl 5.004. Additionally defining PLAIN_MALLOC 14 returns it to the state as of Perl 5.000. 15 16 Note that some of the settings below may be ignored in the code based 17 on values of other macros. The PERL_CORE symbol is only defined when 18 perl itself is being compiled (so malloc can make some assumptions 19 about perl's facilities being available to it). 20 21 Each config option has a short description, followed by its name, 22 default value, and a comment about the default (if applicable). Some 23 options take a precise value, while the others are just boolean. 24 The boolean ones are listed first. 25 26 # Enable code for an emergency memory pool in $^M. See perlvar.pod 27 # for a description of $^M. 28 PERL_EMERGENCY_SBRK (!PLAIN_MALLOC && PERL_CORE) 29 30 # Enable code for printing memory statistics. 31 DEBUGGING_MSTATS (!PLAIN_MALLOC && PERL_CORE) 32 33 # Move allocation info for small buckets into separate areas. 34 # Memory optimization (especially for small allocations, of the 35 # less than 64 bytes). Since perl usually makes a large number 36 # of small allocations, this is usually a win. 37 PACK_MALLOC (!PLAIN_MALLOC && !RCHECK) 38 39 # Add one page to big powers of two when calculating bucket size. 40 # This is targeted at big allocations, as are common in image 41 # processing. 42 TWO_POT_OPTIMIZE !PLAIN_MALLOC 43 44 # Use intermediate bucket sizes between powers-of-two. This is 45 # generally a memory optimization, and a (small) speed pessimization. 46 BUCKETS_ROOT2 !NO_FANCY_MALLOC 47 48 # Do not check small deallocations for bad free(). Memory 49 # and speed optimization, error reporting pessimization. 50 IGNORE_SMALL_BAD_FREE (!NO_FANCY_MALLOC && !RCHECK) 51 52 # Use table lookup to decide in which bucket a given allocation will go. 53 SMALL_BUCKET_VIA_TABLE !NO_FANCY_MALLOC 54 55 # Use a perl-defined sbrk() instead of the (presumably broken or 56 # missing) system-supplied sbrk(). 57 USE_PERL_SBRK undef 58 59 # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally 60 # only used with broken sbrk()s. 61 PERL_SBRK_VIA_MALLOC undef 62 63 # Which allocator to use if PERL_SBRK_VIA_MALLOC 64 SYSTEM_ALLOC(a) malloc(a) 65 66 # Minimal alignment (in bytes, should be a power of 2) of SYSTEM_ALLOC 67 SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES 68 69 # Disable memory overwrite checking with DEBUGGING. Memory and speed 70 # optimization, error reporting pessimization. 71 NO_RCHECK undef 72 73 # Enable memory overwrite checking with DEBUGGING. Memory and speed 74 # pessimization, error reporting optimization 75 RCHECK (DEBUGGING && !NO_RCHECK) 76 77 # Failed allocations bigger than this size croak (if 78 # PERL_EMERGENCY_SBRK is enabled) without touching $^M. See 79 # perlvar.pod for a description of $^M. 80 BIG_SIZE (1<<16) # 64K 81 82 # Starting from this power of two, add an extra page to the 83 # size of the bucket. This enables optimized allocations of sizes 84 # close to powers of 2. Note that the value is indexed at 0. 85 FIRST_BIG_POW2 15 # 32K, 16K is used too often 86 87 # Estimate of minimal memory footprint. malloc uses this value to 88 # request the most reasonable largest blocks of memory from the system. 89 FIRST_SBRK (48*1024) 90 91 # Round up sbrk()s to multiples of this. 92 MIN_SBRK 2048 93 94 # Round up sbrk()s to multiples of this percent of footprint. 95 MIN_SBRK_FRAC 3 96 97 # Add this much memory to big powers of two to get the bucket size. 98 PERL_PAGESIZE 4096 99 100 # This many sbrk() discontinuities should be tolerated even 101 # from the start without deciding that sbrk() is usually 102 # discontinuous. 103 SBRK_ALLOW_FAILURES 3 104 105 # This many continuous sbrk()s compensate for one discontinuous one. 106 SBRK_FAILURE_PRICE 50 107 108 # Some configurations may ask for 12-byte-or-so allocations which 109 # require 8-byte alignment (?!). In such situation one needs to 110 # define this to disable 12-byte bucket (will increase memory footprint) 111 STRICT_ALIGNMENT undef 112 113 This implementation assumes that calling PerlIO_printf() does not 114 result in any memory allocation calls (used during a panic). 115 116 */ 117 118 /* 119 If used outside of Perl environment, it may be useful to redefine 120 the following macros (listed below with defaults): 121 122 # Type of address returned by allocation functions 123 Malloc_t void * 124 125 # Type of size argument for allocation functions 126 MEM_SIZE unsigned long 127 128 # size of void* 129 PTRSIZE 4 130 131 # Maximal value in LONG 132 LONG_MAX 0x7FFFFFFF 133 134 # Unsigned integer type big enough to keep a pointer 135 UV unsigned long 136 137 # Type of pointer with 1-byte granularity 138 caddr_t char * 139 140 # Type returned by free() 141 Free_t void 142 143 # Very fatal condition reporting function (cannot call any ) 144 fatalcroak(arg) write(2,arg,strlen(arg)) + exit(2) 145 146 # Fatal error reporting function 147 croak(format, arg) warn(idem) + exit(1) 148 149 # Fatal error reporting function 150 croak2(format, arg1, arg2) warn2(idem) + exit(1) 151 152 # Error reporting function 153 warn(format, arg) fprintf(stderr, idem) 154 155 # Error reporting function 156 warn2(format, arg1, arg2) fprintf(stderr, idem) 157 158 # Locking/unlocking for MT operation 159 MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex) 160 MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex) 161 162 # Locking/unlocking mutex for MT operation 163 MUTEX_LOCK(l) void 164 MUTEX_UNLOCK(l) void 165 */ 166 167 #ifndef NO_FANCY_MALLOC 168 # ifndef SMALL_BUCKET_VIA_TABLE 169 # define SMALL_BUCKET_VIA_TABLE 170 # endif 171 # ifndef BUCKETS_ROOT2 172 # define BUCKETS_ROOT2 173 # endif 174 # ifndef IGNORE_SMALL_BAD_FREE 175 # define IGNORE_SMALL_BAD_FREE 176 # endif 177 #endif 178 179 #ifndef PLAIN_MALLOC /* Bulk enable features */ 180 # ifndef PACK_MALLOC 181 # define PACK_MALLOC 182 # endif 183 # ifndef TWO_POT_OPTIMIZE 184 # define TWO_POT_OPTIMIZE 185 # endif 186 # if defined(PERL_CORE) && !defined(PERL_EMERGENCY_SBRK) 187 # define PERL_EMERGENCY_SBRK 188 # endif 189 # if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS) 190 # define DEBUGGING_MSTATS 191 # endif 192 #endif 193 194 #define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */ 195 #define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2) 196 197 #if !(defined(I286) || defined(atarist) || defined(__MINT__)) 198 /* take 2k unless the block is bigger than that */ 199 # define LOG_OF_MIN_ARENA 11 200 #else 201 /* take 16k unless the block is bigger than that 202 (80286s like large segments!), probably good on the atari too */ 203 # define LOG_OF_MIN_ARENA 14 204 #endif 205 206 #ifndef lint 207 # if defined(DEBUGGING) && !defined(NO_RCHECK) 208 # define RCHECK 209 # endif 210 # if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE) 211 # undef IGNORE_SMALL_BAD_FREE 212 # endif 213 /* 214 * malloc.c (Caltech) 2/21/82 215 * Chris Kingsley, kingsley@cit-20. 216 * 217 * This is a very fast storage allocator. It allocates blocks of a small 218 * number of different sizes, and keeps free lists of each size. Blocks that 219 * don't exactly fit are passed up to the next larger size. In this 220 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long. 221 * If PACK_MALLOC is defined, small blocks are 2^n bytes long. 222 * This is designed for use in a program that uses vast quantities of memory, 223 * but bombs when it runs out. 224 * 225 * Modifications Copyright Ilya Zakharevich 1996-99. 226 * 227 * Still very quick, but much more thrifty. (Std config is 10% slower 228 * than it was, and takes 67% of old heap size for typical usage.) 229 * 230 * Allocations of small blocks are now table-driven to many different 231 * buckets. Sizes of really big buckets are increased to accomodata 232 * common size=power-of-2 blocks. Running-out-of-memory is made into 233 * an exception. Deeply configurable and thread-safe. 234 * 235 */ 236 237 #ifdef PERL_CORE 238 # include "EXTERN.h" 239 # define PERL_IN_MALLOC_C 240 # include "perl.h" 241 # if defined(PERL_IMPLICIT_CONTEXT) 242 # define croak Perl_croak_nocontext 243 # define croak2 Perl_croak_nocontext 244 # define warn Perl_warn_nocontext 245 # define warn2 Perl_warn_nocontext 246 # else 247 # define croak2 croak 248 # define warn2 warn 249 # endif 250 #else 251 # ifdef PERL_FOR_X2P 252 # include "../EXTERN.h" 253 # include "../perl.h" 254 # else 255 # include <stdlib.h> 256 # include <stdio.h> 257 # include <memory.h> 258 # define _(arg) arg 259 # ifndef Malloc_t 260 # define Malloc_t void * 261 # endif 262 # ifndef PTRSIZE 263 # define PTRSIZE 4 264 # endif 265 # ifndef MEM_SIZE 266 # define MEM_SIZE unsigned long 267 # endif 268 # ifndef LONG_MAX 269 # define LONG_MAX 0x7FFFFFFF 270 # endif 271 # ifndef UV 272 # define UV unsigned long 273 # endif 274 # ifndef caddr_t 275 # define caddr_t char * 276 # endif 277 # ifndef Free_t 278 # define Free_t void 279 # endif 280 # define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t)) 281 # define PerlEnv_getenv getenv 282 # define PerlIO_printf fprintf 283 # define PerlIO_stderr() stderr 284 # endif 285 # ifndef croak /* make depend */ 286 # define croak(mess, arg) (warn((mess), (arg)), exit(1)) 287 # endif 288 # ifndef croak2 /* make depend */ 289 # define croak2(mess, arg1, arg2) (warn2((mess), (arg1), (arg2)), exit(1)) 290 # endif 291 # ifndef warn 292 # define warn(mess, arg) fprintf(stderr, (mess), (arg)) 293 # endif 294 # ifndef warn2 295 # define warn2(mess, arg1) fprintf(stderr, (mess), (arg1), (arg2)) 296 # endif 297 # ifdef DEBUG_m 298 # undef DEBUG_m 299 # endif 300 # define DEBUG_m(a) 301 # ifdef DEBUGGING 302 # undef DEBUGGING 303 # endif 304 # ifndef pTHX 305 # define pTHX void 306 # define pTHX_ 307 # define dTHX extern int Perl___notused 308 # define WITH_THX(s) s 309 # endif 310 # ifndef PERL_GET_INTERP 311 # define PERL_GET_INTERP PL_curinterp 312 # endif 313 # ifndef Perl_malloc 314 # define Perl_malloc malloc 315 # endif 316 # ifndef Perl_mfree 317 # define Perl_mfree free 318 # endif 319 # ifndef Perl_realloc 320 # define Perl_realloc realloc 321 # endif 322 # ifndef Perl_calloc 323 # define Perl_calloc calloc 324 # endif 325 # ifndef Perl_strdup 326 # define Perl_strdup strdup 327 # endif 328 #endif 329 330 #ifndef MUTEX_LOCK 331 # define MUTEX_LOCK(l) 332 #endif 333 334 #ifndef MUTEX_UNLOCK 335 # define MUTEX_UNLOCK(l) 336 #endif 337 338 #ifndef MALLOC_LOCK 339 # define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex) 340 #endif 341 342 #ifndef MALLOC_UNLOCK 343 # define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex) 344 #endif 345 346 # ifndef fatalcroak /* make depend */ 347 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2)) 348 # endif 349 350 #ifdef DEBUGGING 351 # undef DEBUG_m 352 # define DEBUG_m(a) \ 353 STMT_START { \ 354 if (PERL_GET_INTERP) { dTHX; if (PL_debug & 128) { a; } } \ 355 } STMT_END 356 #endif 357 358 #ifdef PERL_IMPLICIT_CONTEXT 359 # define PERL_IS_ALIVE aTHX 360 #else 361 # define PERL_IS_ALIVE TRUE 362 #endif 363 364 365 /* 366 * Layout of memory: 367 * ~~~~~~~~~~~~~~~~ 368 * The memory is broken into "blocks" which occupy multiples of 2K (and 369 * generally speaking, have size "close" to a power of 2). The addresses 370 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf 371 * is an array of linked lists.) (Addresses of used blocks are not known.) 372 * 373 * Moreover, since the algorithm may try to "bite" smaller blocks out 374 * of unused bigger ones, there are also regions of "irregular" size, 375 * managed separately, by a linked list chunk_chain. 376 * 377 * The third type of storage is the sbrk()ed-but-not-yet-used space, its 378 * end and size are kept in last_sbrk_top and sbrked_remains. 379 * 380 * Growing blocks "in place": 381 * ~~~~~~~~~~~~~~~~~~~~~~~~~ 382 * The address of the block with the greatest address is kept in last_op 383 * (if not known, last_op is 0). If it is known that the memory above 384 * last_op is not continuous, or contains a chunk from chunk_chain, 385 * last_op is set to 0. 386 * 387 * The chunk with address last_op may be grown by expanding into 388 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous 389 * memory. 390 * 391 * Management of last_op: 392 * ~~~~~~~~~~~~~~~~~~~~~ 393 * 394 * free() never changes the boundaries of blocks, so is not relevant. 395 * 396 * The only way realloc() may change the boundaries of blocks is if it 397 * grows a block "in place". However, in the case of success such a 398 * chunk is automatically last_op, and it remains last_op. In the case 399 * of failure getpages_adjacent() clears last_op. 400 * 401 * malloc() may change blocks by calling morecore() only. 402 * 403 * morecore() may create new blocks by: 404 * a) biting pieces from chunk_chain (cannot create one above last_op); 405 * b) biting a piece from an unused block (if block was last_op, this 406 * may create a chunk from chain above last_op, thus last_op is 407 * invalidated in such a case). 408 * c) biting of sbrk()ed-but-not-yet-used space. This creates 409 * a block which is last_op. 410 * d) Allocating new pages by calling getpages(); 411 * 412 * getpages() creates a new block. It marks last_op at the bottom of 413 * the chunk of memory it returns. 414 * 415 * Active pages footprint: 416 * ~~~~~~~~~~~~~~~~~~~~~~ 417 * Note that we do not need to traverse the lists in nextf[i], just take 418 * the first element of this list. However, we *need* to traverse the 419 * list in chunk_chain, but most the time it should be a very short one, 420 * so we do not step on a lot of pages we are not going to use. 421 * 422 * Flaws: 423 * ~~~~~ 424 * get_from_bigger_buckets(): forget to increment price => Quite 425 * aggressive. 426 */ 427 428 /* I don't much care whether these are defined in sys/types.h--LAW */ 429 430 #define u_char unsigned char 431 #define u_int unsigned int 432 /* 433 * I removed the definition of u_bigint which appeared to be u_bigint = UV 434 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT 435 * where I have used PTR2UV. RMB 436 */ 437 #define u_short unsigned short 438 439 /* 286 and atarist like big chunks, which gives too much overhead. */ 440 #if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC) 441 # undef PACK_MALLOC 442 #endif 443 444 /* 445 * The description below is applicable if PACK_MALLOC is not defined. 446 * 447 * The overhead on a block is at least 4 bytes. When free, this space 448 * contains a pointer to the next free block, and the bottom two bits must 449 * be zero. When in use, the first byte is set to MAGIC, and the second 450 * byte is the size index. The remaining bytes are for alignment. 451 * If range checking is enabled and the size of the block fits 452 * in two bytes, then the top two bytes hold the size of the requested block 453 * plus the range checking words, and the header word MINUS ONE. 454 */ 455 union overhead { 456 union overhead *ov_next; /* when free */ 457 #if MEM_ALIGNBYTES > 4 458 double strut; /* alignment problems */ 459 #endif 460 struct { 461 /* 462 * Keep the ovu_index and ovu_magic in this order, having a char 463 * field first gives alignment indigestion in some systems, such as 464 * MachTen. 465 */ 466 u_char ovu_index; /* bucket # */ 467 u_char ovu_magic; /* magic number */ 468 #ifdef RCHECK 469 u_short ovu_size; /* actual block size */ 470 u_int ovu_rmagic; /* range magic number */ 471 #endif 472 } ovu; 473 #define ov_magic ovu.ovu_magic 474 #define ov_index ovu.ovu_index 475 #define ov_size ovu.ovu_size 476 #define ov_rmagic ovu.ovu_rmagic 477 }; 478 479 #define MAGIC 0xff /* magic # on accounting info */ 480 #define RMAGIC 0x55555555 /* magic # on range info */ 481 #define RMAGIC_C 0x55 /* magic # on range info */ 482 483 #ifdef RCHECK 484 # define RSLOP sizeof (u_int) 485 # ifdef TWO_POT_OPTIMIZE 486 # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2) 487 # else 488 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2) 489 # endif 490 #else 491 # define RSLOP 0 492 #endif 493 494 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2) 495 # undef BUCKETS_ROOT2 496 #endif 497 498 #ifdef BUCKETS_ROOT2 499 # define BUCKET_TABLE_SHIFT 2 500 # define BUCKET_POW2_SHIFT 1 501 # define BUCKETS_PER_POW2 2 502 #else 503 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2 504 # define BUCKET_POW2_SHIFT 0 505 # define BUCKETS_PER_POW2 1 506 #endif 507 508 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT)) 509 /* Figure out the alignment of void*. */ 510 struct aligner { 511 char c; 512 void *p; 513 }; 514 # define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p))) 515 #else 516 # define ALIGN_SMALL MEM_ALIGNBYTES 517 #endif 518 519 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no)) 520 521 #ifdef BUCKETS_ROOT2 522 # define MAX_BUCKET_BY_TABLE 13 523 static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] = 524 { 525 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80, 526 }; 527 # define BUCKET_SIZE(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT))) 528 # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \ 529 ? buck_size[i] \ 530 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \ 531 - MEM_OVERHEAD(i) \ 532 + POW2_OPTIMIZE_SURPLUS(i))) 533 #else 534 # define BUCKET_SIZE(i) (1 << ((i) >> BUCKET_POW2_SHIFT)) 535 # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i) + POW2_OPTIMIZE_SURPLUS(i)) 536 #endif 537 538 539 #ifdef PACK_MALLOC 540 /* In this case there are several possible layout of arenas depending 541 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and 542 * have a size close to a power of 2. 543 * 544 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K 545 * may keep one chunk or multiple chunks. Here are the possible 546 * layouts of arenas: 547 * 548 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11 549 * 550 * INDEX MAGIC1 UNUSED CHUNK1 551 * 552 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7 553 * 554 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ... 555 * 556 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7 557 * 558 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ... 559 * 560 * # Multichunk with sanity checking and size up to 80 561 * 562 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ... 563 * 564 * # No sanity check (usually up to 48=byte-long buckets) 565 * INDEX UNUSED CHUNK1 CHUNK2 ... 566 * 567 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are 568 * appropriate to keep algorithms simple and memory aligned. INDEX 569 * encodes the size of the chunk, while MAGICn encodes state (used, 570 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC 571 * is used for sanity checking purposes only. SOMETHING is 0 or 4K 572 * (to make size of big CHUNK accomodate allocations for powers of two 573 * better). 574 * 575 * [There is no need to alignment between chunks, since C rules ensure 576 * that structs which need 2^k alignment have sizeof which is 577 * divisible by 2^k. Thus as far as the last chunk is aligned at the 578 * end of the arena, and 2K-alignment does not contradict things, 579 * everything is going to be OK for sizes of chunks 2^n and 2^n + 580 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we 581 * put allocations for requests in 65..80 range, all is fine. 582 * 583 * Note, however, that standard malloc() puts more strict 584 * requirements than the above C rules. Moreover, our algorithms of 585 * realloc() may break this idyll, but we suppose that realloc() does 586 * need not change alignment.] 587 * 588 * Is very important to make calculation of the offset of MAGICm as 589 * quick as possible, since it is done on each malloc()/free(). In 590 * fact it is so quick that it has quite little effect on the speed of 591 * doing malloc()/free(). [By default] We forego such calculations 592 * for small chunks, but only to save extra 3% of memory, not because 593 * of speed considerations. 594 * 595 * Here is the algorithm [which is the same for all the allocations 596 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the 597 * offset of the CHUNKm from the start of ARENA. Then offset of 598 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET 599 * are numbers which depend on the size of the chunks only. 600 * 601 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are 602 * different for all the chunks in the arena if 2^SHIFT is not greater 603 * than size of the chunks in the arena. MAGIC1 will not overwrite 604 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast 605 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) + 606 * ADDOFFSET. 607 * 608 * Make SHIFT the maximal possible (there is no point in making it 609 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions 610 * give restrictions on OFFSET1 and on ADDOFFSET. 611 * 612 * In particular, for chunks of size 2^k with k>=6 we can put 613 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have 614 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is 615 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96, 616 * when ADDOFFSET should be 1). In particular, keeping MAGICs for 617 * these sizes gives no additional size penalty. 618 * 619 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >= 620 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k) 621 * chunks per arena. This is smaller than 2^(11-k) - 1 which are 622 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET 623 * would allow for slightly more buckets per arena for k=2,3.] 624 * 625 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span 626 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal 627 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny 628 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16 629 * (with no savings for negative values). 630 * 631 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6 632 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and 633 * leads to no contradictions except for size=80 (or 96.) 634 * 635 * However, it also makes sense to keep no magic for sizes 48 or less. 636 * This is what we do. In this case one needs ADDOFFSET>=1 also for 637 * chunksizes 12, 24, and 48, unless one gets one less chunk per 638 * arena. 639 * 640 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until 641 * chunksize of 64, then makes it 1. 642 * 643 * This allows for an additional optimization: the above scheme leads 644 * to giant overheads for sizes 128 or more (one whole chunk needs to 645 * be sacrifised to keep INDEX). Instead we use chunks not of size 646 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of 647 * the arena, then the beginnings are still in different 2^k-long 648 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8. 649 * Thus for k>7 the above algo of calculating the offset of the magic 650 * will still give different answers for different chunks. And to 651 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1. 652 * In the case k=7 we just move the first chunk an extra ALIGN 653 * backward inside the ARENA (this is done once per arena lifetime, 654 * thus is not a big overhead). */ 655 # define MAX_PACKED_POW2 6 656 # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT) 657 # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD) 658 # define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1) 659 # define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK) 660 # define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK) 661 # define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block))) 662 # define OV_INDEX(block) (*OV_INDEXp(block)) 663 # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \ 664 (TWOK_SHIFT(block)>> \ 665 (bucket>>BUCKET_POW2_SHIFT)) + \ 666 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0))) 667 /* A bucket can have a shift smaller than it size, we need to 668 shift its magic number so it will not overwrite index: */ 669 # ifdef BUCKETS_ROOT2 670 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */ 671 # else 672 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */ 673 # endif 674 # define CHUNK_SHIFT 0 675 676 /* Number of active buckets of given ordinal. */ 677 #ifdef IGNORE_SMALL_BAD_FREE 678 #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */ 679 # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \ 680 ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE(bucket) \ 681 : n_blks[bucket] ) 682 #else 683 # define N_BLKS(bucket) n_blks[bucket] 684 #endif 685 686 static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] = 687 { 688 # if BUCKETS_PER_POW2==1 689 0, 0, 690 (MIN_BUC_POW2==2 ? 384 : 0), 691 224, 120, 62, 31, 16, 8, 4, 2 692 # else 693 0, 0, 0, 0, 694 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */ 695 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2 696 # endif 697 }; 698 699 /* Shift of the first bucket with the given ordinal inside 2K chunk. */ 700 #ifdef IGNORE_SMALL_BAD_FREE 701 # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \ 702 ? ((1<<LOG_OF_MIN_ARENA) \ 703 - BUCKET_SIZE(bucket) * N_BLKS(bucket)) \ 704 : blk_shift[bucket]) 705 #else 706 # define BLK_SHIFT(bucket) blk_shift[bucket] 707 #endif 708 709 static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] = 710 { 711 # if BUCKETS_PER_POW2==1 712 0, 0, 713 (MIN_BUC_POW2==2 ? 512 : 0), 714 256, 128, 64, 64, /* 8 to 64 */ 715 16*sizeof(union overhead), 716 8*sizeof(union overhead), 717 4*sizeof(union overhead), 718 2*sizeof(union overhead), 719 # else 720 0, 0, 0, 0, 721 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0), 722 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */ 723 16*sizeof(union overhead), 16*sizeof(union overhead), 724 8*sizeof(union overhead), 8*sizeof(union overhead), 725 4*sizeof(union overhead), 4*sizeof(union overhead), 726 2*sizeof(union overhead), 2*sizeof(union overhead), 727 # endif 728 }; 729 730 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */ 731 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */ 732 733 #else /* !PACK_MALLOC */ 734 735 # define OV_MAGIC(block,bucket) (block)->ov_magic 736 # define OV_INDEX(block) (block)->ov_index 737 # define CHUNK_SHIFT 1 738 # define MAX_PACKED -1 739 # define NEEDED_ALIGNMENT MEM_ALIGNBYTES 740 # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */ 741 742 #endif /* !PACK_MALLOC */ 743 744 #define M_OVERHEAD (sizeof(union overhead) + RSLOP) 745 746 #ifdef PACK_MALLOC 747 # define MEM_OVERHEAD(bucket) \ 748 (bucket <= MAX_PACKED ? 0 : M_OVERHEAD) 749 # ifdef SMALL_BUCKET_VIA_TABLE 750 # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2) 751 # define START_SHIFT MAX_PACKED_POW2 752 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */ 753 # define SIZE_TABLE_MAX 80 754 # else 755 # define SIZE_TABLE_MAX 64 756 # endif 757 static char bucket_of[] = 758 { 759 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */ 760 /* 0 to 15 in 4-byte increments. */ 761 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */ 762 6, /* 8 */ 763 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */ 764 9, 9, 10, 10, /* 24, 32 */ 765 11, 11, 11, 11, /* 48 */ 766 12, 12, 12, 12, /* 64 */ 767 13, 13, 13, 13, /* 80 */ 768 13, 13, 13, 13 /* 80 */ 769 # else /* !BUCKETS_ROOT2 */ 770 /* 0 to 15 in 4-byte increments. */ 771 (sizeof(void*) > 4 ? 3 : 2), 772 3, 773 4, 4, 774 5, 5, 5, 5, 775 6, 6, 6, 6, 776 6, 6, 6, 6 777 # endif /* !BUCKETS_ROOT2 */ 778 }; 779 # else /* !SMALL_BUCKET_VIA_TABLE */ 780 # define START_SHIFTS_BUCKET MIN_BUCKET 781 # define START_SHIFT (MIN_BUC_POW2 - 1) 782 # endif /* !SMALL_BUCKET_VIA_TABLE */ 783 #else /* !PACK_MALLOC */ 784 # define MEM_OVERHEAD(bucket) M_OVERHEAD 785 # ifdef SMALL_BUCKET_VIA_TABLE 786 # undef SMALL_BUCKET_VIA_TABLE 787 # endif 788 # define START_SHIFTS_BUCKET MIN_BUCKET 789 # define START_SHIFT (MIN_BUC_POW2 - 1) 790 #endif /* !PACK_MALLOC */ 791 792 /* 793 * Big allocations are often of the size 2^n bytes. To make them a 794 * little bit better, make blocks of size 2^n+pagesize for big n. 795 */ 796 797 #ifdef TWO_POT_OPTIMIZE 798 799 # ifndef PERL_PAGESIZE 800 # define PERL_PAGESIZE 4096 801 # endif 802 # ifndef FIRST_BIG_POW2 803 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */ 804 # endif 805 # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2) 806 /* If this value or more, check against bigger blocks. */ 807 # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD) 808 /* If less than this value, goes into 2^n-overhead-block. */ 809 # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD) 810 811 # define POW2_OPTIMIZE_ADJUST(nbytes) \ 812 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0) 813 # define POW2_OPTIMIZE_SURPLUS(bucket) \ 814 ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0) 815 816 #else /* !TWO_POT_OPTIMIZE */ 817 # define POW2_OPTIMIZE_ADJUST(nbytes) 818 # define POW2_OPTIMIZE_SURPLUS(bucket) 0 819 #endif /* !TWO_POT_OPTIMIZE */ 820 821 #if defined(HAS_64K_LIMIT) && defined(PERL_CORE) 822 # define BARK_64K_LIMIT(what,nbytes,size) \ 823 if (nbytes > 0xffff) { \ 824 PerlIO_printf(PerlIO_stderr(), \ 825 "%s too large: %lx\n", what, size); \ 826 my_exit(1); \ 827 } 828 #else /* !HAS_64K_LIMIT || !PERL_CORE */ 829 # define BARK_64K_LIMIT(what,nbytes,size) 830 #endif /* !HAS_64K_LIMIT || !PERL_CORE */ 831 832 #ifndef MIN_SBRK 833 # define MIN_SBRK 2048 834 #endif 835 836 #ifndef FIRST_SBRK 837 # define FIRST_SBRK (48*1024) 838 #endif 839 840 /* Minimal sbrk in percents of what is already alloced. */ 841 #ifndef MIN_SBRK_FRAC 842 # define MIN_SBRK_FRAC 3 843 #endif 844 845 #ifndef SBRK_ALLOW_FAILURES 846 # define SBRK_ALLOW_FAILURES 3 847 #endif 848 849 #ifndef SBRK_FAILURE_PRICE 850 # define SBRK_FAILURE_PRICE 50 851 #endif 852 853 static void morecore (register int bucket); 854 # if defined(DEBUGGING) 855 static void botch (char *diag, char *s); 856 # endif 857 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip); 858 static void* get_from_chain (MEM_SIZE size); 859 static void* get_from_bigger_buckets(int bucket, MEM_SIZE size); 860 static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket); 861 static int getpages_adjacent(MEM_SIZE require); 862 863 #ifdef PERL_CORE 864 865 #ifdef I_MACH_CTHREADS 866 # undef MUTEX_LOCK 867 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END 868 # undef MUTEX_UNLOCK 869 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END 870 #endif 871 872 #ifndef BITS_IN_PTR 873 # define BITS_IN_PTR (8*PTRSIZE) 874 #endif 875 876 /* 877 * nextf[i] is the pointer to the next free block of size 2^i. The 878 * smallest allocatable block is 8 bytes. The overhead information 879 * precedes the data area returned to the user. 880 */ 881 #define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1) 882 static union overhead *nextf[NBUCKETS]; 883 884 #if defined(PURIFY) && !defined(USE_PERL_SBRK) 885 # define USE_PERL_SBRK 886 #endif 887 888 #ifdef USE_PERL_SBRK 889 # define sbrk(a) Perl_sbrk(a) 890 Malloc_t Perl_sbrk (int size); 891 #else 892 #ifndef HAS_SBRK_PROTO 893 extern Malloc_t sbrk(int); 894 #endif 895 #endif 896 897 #ifdef DEBUGGING_MSTATS 898 /* 899 * nmalloc[i] is the difference between the number of mallocs and frees 900 * for a given block size. 901 */ 902 static u_int nmalloc[NBUCKETS]; 903 static u_int sbrk_slack; 904 static u_int start_slack; 905 #else /* !( defined DEBUGGING_MSTATS ) */ 906 # define sbrk_slack 0 907 #endif 908 909 static u_int goodsbrk; 910 911 # ifdef PERL_EMERGENCY_SBRK 912 913 # ifndef BIG_SIZE 914 # define BIG_SIZE (1<<16) /* 64K */ 915 # endif 916 917 static char *emergency_buffer; 918 static MEM_SIZE emergency_buffer_size; 919 static int no_mem; /* 0 if the last request for more memory succeeded. 920 Otherwise the size of the failing request. */ 921 922 static Malloc_t 923 emergency_sbrk(MEM_SIZE size) 924 { 925 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA; 926 927 if (size >= BIG_SIZE && (!no_mem || (size < no_mem))) { 928 /* Give the possibility to recover, but avoid an infinite cycle. */ 929 MALLOC_UNLOCK; 930 no_mem = size; 931 croak2("Out of memory during \"large\" request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack)); 932 } 933 934 if (emergency_buffer_size >= rsize) { 935 char *old = emergency_buffer; 936 937 emergency_buffer_size -= rsize; 938 emergency_buffer += rsize; 939 return old; 940 } else { 941 dTHX; 942 /* First offense, give a possibility to recover by dieing. */ 943 /* No malloc involved here: */ 944 GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0); 945 SV *sv; 946 char *pv; 947 int have = 0; 948 STRLEN n_a; 949 950 if (emergency_buffer_size) { 951 add_to_chain(emergency_buffer, emergency_buffer_size, 0); 952 emergency_buffer_size = 0; 953 emergency_buffer = Nullch; 954 have = 1; 955 } 956 if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0); 957 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv) 958 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD)) { 959 if (have) 960 goto do_croak; 961 return (char *)-1; /* Now die die die... */ 962 } 963 /* Got it, now detach SvPV: */ 964 pv = SvPV(sv, n_a); 965 /* Check alignment: */ 966 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) { 967 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n"); 968 return (char *)-1; /* die die die */ 969 } 970 971 emergency_buffer = pv - sizeof(union overhead); 972 emergency_buffer_size = malloced_size(pv) + M_OVERHEAD; 973 SvPOK_off(sv); 974 SvPVX(sv) = Nullch; 975 SvCUR(sv) = SvLEN(sv) = 0; 976 } 977 do_croak: 978 MALLOC_UNLOCK; 979 croak("Out of memory during request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack)); 980 /* NOTREACHED */ 981 return Nullch; 982 } 983 984 # else /* !defined(PERL_EMERGENCY_SBRK) */ 985 # define emergency_sbrk(size) -1 986 # endif 987 #endif /* ifdef PERL_CORE */ 988 989 #ifdef DEBUGGING 990 #undef ASSERT 991 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p)); else 992 static void 993 botch(char *diag, char *s) 994 { 995 dTHX; 996 PerlIO_printf(PerlIO_stderr(), "assertion botched (%s?): %s\n", diag, s); 997 PerlProc_abort(); 998 } 999 #else 1000 #define ASSERT(p, diag) 1001 #endif 1002 1003 Malloc_t 1004 Perl_malloc(register size_t nbytes) 1005 { 1006 register union overhead *p; 1007 register int bucket; 1008 register MEM_SIZE shiftr; 1009 1010 #if defined(DEBUGGING) || defined(RCHECK) 1011 MEM_SIZE size = nbytes; 1012 #endif 1013 1014 BARK_64K_LIMIT("Allocation",nbytes,nbytes); 1015 #ifdef DEBUGGING 1016 if ((long)nbytes < 0) 1017 croak("%s", "panic: malloc"); 1018 #endif 1019 1020 /* 1021 * Convert amount of memory requested into 1022 * closest block size stored in hash buckets 1023 * which satisfies request. Account for 1024 * space used per block for accounting. 1025 */ 1026 #ifdef PACK_MALLOC 1027 # ifdef SMALL_BUCKET_VIA_TABLE 1028 if (nbytes == 0) 1029 bucket = MIN_BUCKET; 1030 else if (nbytes <= SIZE_TABLE_MAX) { 1031 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT]; 1032 } else 1033 # else 1034 if (nbytes == 0) 1035 nbytes = 1; 1036 if (nbytes <= MAX_POW2_ALGO) goto do_shifts; 1037 else 1038 # endif 1039 #endif 1040 { 1041 POW2_OPTIMIZE_ADJUST(nbytes); 1042 nbytes += M_OVERHEAD; 1043 nbytes = (nbytes + 3) &~ 3; 1044 do_shifts: 1045 shiftr = (nbytes - 1) >> START_SHIFT; 1046 bucket = START_SHIFTS_BUCKET; 1047 /* apart from this loop, this is O(1) */ 1048 while (shiftr >>= 1) 1049 bucket += BUCKETS_PER_POW2; 1050 } 1051 MALLOC_LOCK; 1052 /* 1053 * If nothing in hash bucket right now, 1054 * request more memory from the system. 1055 */ 1056 if (nextf[bucket] == NULL) 1057 morecore(bucket); 1058 if ((p = nextf[bucket]) == NULL) { 1059 MALLOC_UNLOCK; 1060 #ifdef PERL_CORE 1061 { 1062 dTHX; 1063 if (!PL_nomemok) { 1064 #if defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) 1065 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n"); 1066 #else 1067 char buff[80]; 1068 char *eb = buff + sizeof(buff) - 1; 1069 char *s = eb; 1070 size_t n = nbytes; 1071 1072 PerlIO_puts(PerlIO_stderr(),"Out of memory during request for "); 1073 #if defined(DEBUGGING) || defined(RCHECK) 1074 n = size; 1075 #endif 1076 *s = 0; 1077 do { 1078 *--s = '0' + (n % 10); 1079 } while (n /= 10); 1080 PerlIO_puts(PerlIO_stderr(),s); 1081 PerlIO_puts(PerlIO_stderr()," bytes, total sbrk() is "); 1082 s = eb; 1083 n = goodsbrk + sbrk_slack; 1084 do { 1085 *--s = '0' + (n % 10); 1086 } while (n /= 10); 1087 PerlIO_puts(PerlIO_stderr(),s); 1088 PerlIO_puts(PerlIO_stderr()," bytes!\n"); 1089 #endif /* defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) */ 1090 my_exit(1); 1091 } 1092 } 1093 #endif 1094 return (NULL); 1095 } 1096 1097 DEBUG_m(PerlIO_printf(Perl_debug_log, 1098 "0x%"UVxf": (%05lu) malloc %ld bytes\n", 1099 PTR2UV(p), (unsigned long)(PL_an++), 1100 (long)size)); 1101 1102 /* remove from linked list */ 1103 #if defined(RCHECK) 1104 if ((PTR2UV(p)) & (MEM_ALIGNBYTES - 1)) { 1105 dTHX; 1106 PerlIO_printf(PerlIO_stderr(), 1107 "Unaligned pointer in the free chain 0x%"UVxf"\n", 1108 PTR2UV(p)); 1109 } 1110 if ((PTR2UV(p->ov_next)) & (MEM_ALIGNBYTES - 1)) { 1111 dTHX; 1112 PerlIO_printf(PerlIO_stderr(), 1113 "Unaligned `next' pointer in the free " 1114 "chain 0x%"UVxf" at 0x%"UVxf"\n", 1115 PTR2UV(p->ov_next), PTR2UV(p)); 1116 } 1117 #endif 1118 nextf[bucket] = p->ov_next; 1119 1120 MALLOC_UNLOCK; 1121 1122 #ifdef IGNORE_SMALL_BAD_FREE 1123 if (bucket >= FIRST_BUCKET_WITH_CHECK) 1124 #endif 1125 OV_MAGIC(p, bucket) = MAGIC; 1126 #ifndef PACK_MALLOC 1127 OV_INDEX(p) = bucket; 1128 #endif 1129 #ifdef RCHECK 1130 /* 1131 * Record allocated size of block and 1132 * bound space with magic numbers. 1133 */ 1134 p->ov_rmagic = RMAGIC; 1135 if (bucket <= MAX_SHORT_BUCKET) { 1136 int i; 1137 1138 nbytes = size + M_OVERHEAD; 1139 p->ov_size = nbytes - 1; 1140 if ((i = nbytes & 3)) { 1141 i = 4 - i; 1142 while (i--) 1143 *((char *)((caddr_t)p + nbytes - RSLOP + i)) = RMAGIC_C; 1144 } 1145 nbytes = (nbytes + 3) &~ 3; 1146 *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC; 1147 } 1148 #endif 1149 return ((Malloc_t)(p + CHUNK_SHIFT)); 1150 } 1151 1152 static char *last_sbrk_top; 1153 static char *last_op; /* This arena can be easily extended. */ 1154 static int sbrked_remains; 1155 static int sbrk_good = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE; 1156 1157 #ifdef DEBUGGING_MSTATS 1158 static int sbrks; 1159 #endif 1160 1161 struct chunk_chain_s { 1162 struct chunk_chain_s *next; 1163 MEM_SIZE size; 1164 }; 1165 static struct chunk_chain_s *chunk_chain; 1166 static int n_chunks; 1167 static char max_bucket; 1168 1169 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */ 1170 static void * 1171 get_from_chain(MEM_SIZE size) 1172 { 1173 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain; 1174 struct chunk_chain_s **oldgoodp = NULL; 1175 long min_remain = LONG_MAX; 1176 1177 while (elt) { 1178 if (elt->size >= size) { 1179 long remains = elt->size - size; 1180 if (remains >= 0 && remains < min_remain) { 1181 oldgoodp = oldp; 1182 min_remain = remains; 1183 } 1184 if (remains == 0) { 1185 break; 1186 } 1187 } 1188 oldp = &( elt->next ); 1189 elt = elt->next; 1190 } 1191 if (!oldgoodp) return NULL; 1192 if (min_remain) { 1193 void *ret = *oldgoodp; 1194 struct chunk_chain_s *next = (*oldgoodp)->next; 1195 1196 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size); 1197 (*oldgoodp)->size = min_remain; 1198 (*oldgoodp)->next = next; 1199 return ret; 1200 } else { 1201 void *ret = *oldgoodp; 1202 *oldgoodp = (*oldgoodp)->next; 1203 n_chunks--; 1204 return ret; 1205 } 1206 } 1207 1208 static void 1209 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip) 1210 { 1211 struct chunk_chain_s *next = chunk_chain; 1212 char *cp = (char*)p; 1213 1214 cp += chip; 1215 chunk_chain = (struct chunk_chain_s *)cp; 1216 chunk_chain->size = size - chip; 1217 chunk_chain->next = next; 1218 n_chunks++; 1219 } 1220 1221 static void * 1222 get_from_bigger_buckets(int bucket, MEM_SIZE size) 1223 { 1224 int price = 1; 1225 static int bucketprice[NBUCKETS]; 1226 while (bucket <= max_bucket) { 1227 /* We postpone stealing from bigger buckets until we want it 1228 often enough. */ 1229 if (nextf[bucket] && bucketprice[bucket]++ >= price) { 1230 /* Steal it! */ 1231 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT); 1232 bucketprice[bucket] = 0; 1233 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) { 1234 last_op = NULL; /* Disable optimization */ 1235 } 1236 nextf[bucket] = nextf[bucket]->ov_next; 1237 #ifdef DEBUGGING_MSTATS 1238 nmalloc[bucket]--; 1239 start_slack -= M_OVERHEAD; 1240 #endif 1241 add_to_chain(ret, (BUCKET_SIZE(bucket) + 1242 POW2_OPTIMIZE_SURPLUS(bucket)), 1243 size); 1244 return ret; 1245 } 1246 bucket++; 1247 } 1248 return NULL; 1249 } 1250 1251 static union overhead * 1252 getpages(MEM_SIZE needed, int *nblksp, int bucket) 1253 { 1254 /* Need to do (possibly expensive) system call. Try to 1255 optimize it for rare calling. */ 1256 MEM_SIZE require = needed - sbrked_remains; 1257 char *cp; 1258 union overhead *ovp; 1259 MEM_SIZE slack = 0; 1260 1261 if (sbrk_good > 0) { 1262 if (!last_sbrk_top && require < FIRST_SBRK) 1263 require = FIRST_SBRK; 1264 else if (require < MIN_SBRK) require = MIN_SBRK; 1265 1266 if (require < goodsbrk * MIN_SBRK_FRAC / 100) 1267 require = goodsbrk * MIN_SBRK_FRAC / 100; 1268 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK; 1269 } else { 1270 require = needed; 1271 last_sbrk_top = 0; 1272 sbrked_remains = 0; 1273 } 1274 1275 DEBUG_m(PerlIO_printf(Perl_debug_log, 1276 "sbrk(%ld) for %ld-byte-long arena\n", 1277 (long)require, (long) needed)); 1278 cp = (char *)sbrk(require); 1279 #ifdef DEBUGGING_MSTATS 1280 sbrks++; 1281 #endif 1282 if (cp == last_sbrk_top) { 1283 /* Common case, anything is fine. */ 1284 sbrk_good++; 1285 ovp = (union overhead *) (cp - sbrked_remains); 1286 last_op = cp - sbrked_remains; 1287 sbrked_remains = require - (needed - sbrked_remains); 1288 } else if (cp == (char *)-1) { /* no more room! */ 1289 ovp = (union overhead *)emergency_sbrk(needed); 1290 if (ovp == (union overhead *)-1) 1291 return 0; 1292 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */ 1293 last_op = 0; 1294 } 1295 return ovp; 1296 } else { /* Non-continuous or first sbrk(). */ 1297 long add = sbrked_remains; 1298 char *newcp; 1299 1300 if (sbrked_remains) { /* Put rest into chain, we 1301 cannot use it right now. */ 1302 add_to_chain((void*)(last_sbrk_top - sbrked_remains), 1303 sbrked_remains, 0); 1304 } 1305 1306 /* Second, check alignment. */ 1307 slack = 0; 1308 1309 #if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */ 1310 # ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */ 1311 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may 1312 improve performance of memory access. */ 1313 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */ 1314 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)); 1315 add += slack; 1316 } 1317 # endif 1318 #endif /* !atarist && !MINT */ 1319 1320 if (add) { 1321 DEBUG_m(PerlIO_printf(Perl_debug_log, 1322 "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", 1323 (long)add, (long) slack, 1324 (long) sbrked_remains)); 1325 newcp = (char *)sbrk(add); 1326 #if defined(DEBUGGING_MSTATS) 1327 sbrks++; 1328 sbrk_slack += add; 1329 #endif 1330 if (newcp != cp + require) { 1331 /* Too bad: even rounding sbrk() is not continuous.*/ 1332 DEBUG_m(PerlIO_printf(Perl_debug_log, 1333 "failed to fix bad sbrk()\n")); 1334 #ifdef PACK_MALLOC 1335 if (slack) { 1336 MALLOC_UNLOCK; 1337 fatalcroak("panic: Off-page sbrk\n"); 1338 } 1339 #endif 1340 if (sbrked_remains) { 1341 /* Try again. */ 1342 #if defined(DEBUGGING_MSTATS) 1343 sbrk_slack += require; 1344 #endif 1345 require = needed; 1346 DEBUG_m(PerlIO_printf(Perl_debug_log, 1347 "straight sbrk(%ld)\n", 1348 (long)require)); 1349 cp = (char *)sbrk(require); 1350 #ifdef DEBUGGING_MSTATS 1351 sbrks++; 1352 #endif 1353 if (cp == (char *)-1) 1354 return 0; 1355 } 1356 sbrk_good = -1; /* Disable optimization! 1357 Continue with not-aligned... */ 1358 } else { 1359 cp += slack; 1360 require += sbrked_remains; 1361 } 1362 } 1363 1364 if (last_sbrk_top) { 1365 sbrk_good -= SBRK_FAILURE_PRICE; 1366 } 1367 1368 ovp = (union overhead *) cp; 1369 /* 1370 * Round up to minimum allocation size boundary 1371 * and deduct from block count to reflect. 1372 */ 1373 1374 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES 1375 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1)) 1376 fatalcroak("Misalignment of sbrk()\n"); 1377 else 1378 # endif 1379 #ifndef I286 /* Again, this should always be ok on an 80286 */ 1380 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) { 1381 DEBUG_m(PerlIO_printf(Perl_debug_log, 1382 "fixing sbrk(): %d bytes off machine alignement\n", 1383 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)))); 1384 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) & 1385 (MEM_ALIGNBYTES - 1)); 1386 (*nblksp)--; 1387 # if defined(DEBUGGING_MSTATS) 1388 /* This is only approx. if TWO_POT_OPTIMIZE: */ 1389 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT)); 1390 # endif 1391 } 1392 #endif 1393 ; /* Finish `else' */ 1394 sbrked_remains = require - needed; 1395 last_op = cp; 1396 } 1397 #if !defined(PLAIN_MALLOC) && !defined(NO_FANCY_MALLOC) 1398 no_mem = 0; 1399 #endif 1400 last_sbrk_top = cp + require; 1401 #ifdef DEBUGGING_MSTATS 1402 goodsbrk += require; 1403 #endif 1404 return ovp; 1405 } 1406 1407 static int 1408 getpages_adjacent(MEM_SIZE require) 1409 { 1410 if (require <= sbrked_remains) { 1411 sbrked_remains -= require; 1412 } else { 1413 char *cp; 1414 1415 require -= sbrked_remains; 1416 /* We do not try to optimize sbrks here, we go for place. */ 1417 cp = (char*) sbrk(require); 1418 #ifdef DEBUGGING_MSTATS 1419 sbrks++; 1420 goodsbrk += require; 1421 #endif 1422 if (cp == last_sbrk_top) { 1423 sbrked_remains = 0; 1424 last_sbrk_top = cp + require; 1425 } else { 1426 if (cp == (char*)-1) { /* Out of memory */ 1427 #ifdef DEBUGGING_MSTATS 1428 goodsbrk -= require; 1429 #endif 1430 return 0; 1431 } 1432 /* Report the failure: */ 1433 if (sbrked_remains) 1434 add_to_chain((void*)(last_sbrk_top - sbrked_remains), 1435 sbrked_remains, 0); 1436 add_to_chain((void*)cp, require, 0); 1437 sbrk_good -= SBRK_FAILURE_PRICE; 1438 sbrked_remains = 0; 1439 last_sbrk_top = 0; 1440 last_op = 0; 1441 return 0; 1442 } 1443 } 1444 1445 return 1; 1446 } 1447 1448 /* 1449 * Allocate more memory to the indicated bucket. 1450 */ 1451 static void 1452 morecore(register int bucket) 1453 { 1454 register union overhead *ovp; 1455 register int rnu; /* 2^rnu bytes will be requested */ 1456 int nblks; /* become nblks blocks of the desired size */ 1457 register MEM_SIZE siz, needed; 1458 1459 if (nextf[bucket]) 1460 return; 1461 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) { 1462 MALLOC_UNLOCK; 1463 croak("%s", "Out of memory during ridiculously large request"); 1464 } 1465 if (bucket > max_bucket) 1466 max_bucket = bucket; 1467 1468 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT)) 1469 ? LOG_OF_MIN_ARENA 1470 : (bucket >> BUCKET_POW2_SHIFT) ); 1471 /* This may be overwritten later: */ 1472 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */ 1473 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket); 1474 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */ 1475 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT; 1476 nextf[rnu << BUCKET_POW2_SHIFT] 1477 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next; 1478 #ifdef DEBUGGING_MSTATS 1479 nmalloc[rnu << BUCKET_POW2_SHIFT]--; 1480 start_slack -= M_OVERHEAD; 1481 #endif 1482 DEBUG_m(PerlIO_printf(Perl_debug_log, 1483 "stealing %ld bytes from %ld arena\n", 1484 (long) needed, (long) rnu << BUCKET_POW2_SHIFT)); 1485 } else if (chunk_chain 1486 && (ovp = (union overhead*) get_from_chain(needed))) { 1487 DEBUG_m(PerlIO_printf(Perl_debug_log, 1488 "stealing %ld bytes from chain\n", 1489 (long) needed)); 1490 } else if ( (ovp = (union overhead*) 1491 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1, 1492 needed)) ) { 1493 DEBUG_m(PerlIO_printf(Perl_debug_log, 1494 "stealing %ld bytes from bigger buckets\n", 1495 (long) needed)); 1496 } else if (needed <= sbrked_remains) { 1497 ovp = (union overhead *)(last_sbrk_top - sbrked_remains); 1498 sbrked_remains -= needed; 1499 last_op = (char*)ovp; 1500 } else 1501 ovp = getpages(needed, &nblks, bucket); 1502 1503 if (!ovp) 1504 return; 1505 1506 /* 1507 * Add new memory allocated to that on 1508 * free list for this hash bucket. 1509 */ 1510 siz = BUCKET_SIZE(bucket); 1511 #ifdef PACK_MALLOC 1512 *(u_char*)ovp = bucket; /* Fill index. */ 1513 if (bucket <= MAX_PACKED) { 1514 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket)); 1515 nblks = N_BLKS(bucket); 1516 # ifdef DEBUGGING_MSTATS 1517 start_slack += BLK_SHIFT(bucket); 1518 # endif 1519 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) { 1520 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket)); 1521 siz -= sizeof(union overhead); 1522 } else ovp++; /* One chunk per block. */ 1523 #endif /* PACK_MALLOC */ 1524 nextf[bucket] = ovp; 1525 #ifdef DEBUGGING_MSTATS 1526 nmalloc[bucket] += nblks; 1527 if (bucket > MAX_PACKED) { 1528 start_slack += M_OVERHEAD * nblks; 1529 } 1530 #endif 1531 while (--nblks > 0) { 1532 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz); 1533 ovp = (union overhead *)((caddr_t)ovp + siz); 1534 } 1535 /* Not all sbrks return zeroed memory.*/ 1536 ovp->ov_next = (union overhead *)NULL; 1537 #ifdef PACK_MALLOC 1538 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */ 1539 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next; 1540 nextf[7*BUCKETS_PER_POW2] = 1541 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2] 1542 - sizeof(union overhead)); 1543 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op; 1544 } 1545 #endif /* !PACK_MALLOC */ 1546 } 1547 1548 Free_t 1549 Perl_mfree(void *mp) 1550 { 1551 register MEM_SIZE size; 1552 register union overhead *ovp; 1553 char *cp = (char*)mp; 1554 #ifdef PACK_MALLOC 1555 u_char bucket; 1556 #endif 1557 1558 DEBUG_m(PerlIO_printf(Perl_debug_log, 1559 "0x%"UVxf": (%05lu) free\n", 1560 PTR2UV(cp), (unsigned long)(PL_an++))); 1561 1562 if (cp == NULL) 1563 return; 1564 ovp = (union overhead *)((caddr_t)cp 1565 - sizeof (union overhead) * CHUNK_SHIFT); 1566 #ifdef PACK_MALLOC 1567 bucket = OV_INDEX(ovp); 1568 #endif 1569 #ifdef IGNORE_SMALL_BAD_FREE 1570 if ((bucket >= FIRST_BUCKET_WITH_CHECK) 1571 && (OV_MAGIC(ovp, bucket) != MAGIC)) 1572 #else 1573 if (OV_MAGIC(ovp, bucket) != MAGIC) 1574 #endif 1575 { 1576 static int bad_free_warn = -1; 1577 if (bad_free_warn == -1) { 1578 dTHX; 1579 char *pbf = PerlEnv_getenv("PERL_BADFREE"); 1580 bad_free_warn = (pbf) ? atoi(pbf) : 1; 1581 } 1582 if (!bad_free_warn) 1583 return; 1584 #ifdef RCHECK 1585 #ifdef PERL_CORE 1586 { 1587 dTHX; 1588 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC)) 1589 Perl_warner(aTHX_ WARN_MALLOC, "%s free() ignored", 1590 ovp->ov_rmagic == RMAGIC - 1 ? 1591 "Duplicate" : "Bad"); 1592 } 1593 #else 1594 warn("%s free() ignored", 1595 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad"); 1596 #endif 1597 #else 1598 #ifdef PERL_CORE 1599 { 1600 dTHX; 1601 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC)) 1602 Perl_warner(aTHX_ WARN_MALLOC, "%s", "Bad free() ignored"); 1603 } 1604 #else 1605 warn("%s", "Bad free() ignored"); 1606 #endif 1607 #endif 1608 return; /* sanity */ 1609 } 1610 #ifdef RCHECK 1611 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite"); 1612 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) { 1613 int i; 1614 MEM_SIZE nbytes = ovp->ov_size + 1; 1615 1616 if ((i = nbytes & 3)) { 1617 i = 4 - i; 1618 while (i--) { 1619 ASSERT(*((char *)((caddr_t)ovp + nbytes - RSLOP + i)) 1620 == RMAGIC_C, "chunk's tail overwrite"); 1621 } 1622 } 1623 nbytes = (nbytes + 3) &~ 3; 1624 ASSERT(*(u_int *)((caddr_t)ovp + nbytes - RSLOP) == RMAGIC, "chunk's tail overwrite"); 1625 } 1626 ovp->ov_rmagic = RMAGIC - 1; 1627 #endif 1628 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite"); 1629 size = OV_INDEX(ovp); 1630 1631 MALLOC_LOCK; 1632 ovp->ov_next = nextf[size]; 1633 nextf[size] = ovp; 1634 MALLOC_UNLOCK; 1635 } 1636 1637 /* There is no need to do any locking in realloc (with an exception of 1638 trying to grow in place if we are at the end of the chain). 1639 If somebody calls us from a different thread with the same address, 1640 we are sole anyway. */ 1641 1642 Malloc_t 1643 Perl_realloc(void *mp, size_t nbytes) 1644 { 1645 register MEM_SIZE onb; 1646 union overhead *ovp; 1647 char *res; 1648 int prev_bucket; 1649 register int bucket; 1650 int incr; /* 1 if does not fit, -1 if "easily" fits in a 1651 smaller bucket, otherwise 0. */ 1652 char *cp = (char*)mp; 1653 1654 #if defined(DEBUGGING) || !defined(PERL_CORE) 1655 MEM_SIZE size = nbytes; 1656 1657 if ((long)nbytes < 0) 1658 croak("%s", "panic: realloc"); 1659 #endif 1660 1661 BARK_64K_LIMIT("Reallocation",nbytes,size); 1662 if (!cp) 1663 return Perl_malloc(nbytes); 1664 1665 ovp = (union overhead *)((caddr_t)cp 1666 - sizeof (union overhead) * CHUNK_SHIFT); 1667 bucket = OV_INDEX(ovp); 1668 1669 #ifdef IGNORE_SMALL_BAD_FREE 1670 if ((bucket >= FIRST_BUCKET_WITH_CHECK) 1671 && (OV_MAGIC(ovp, bucket) != MAGIC)) 1672 #else 1673 if (OV_MAGIC(ovp, bucket) != MAGIC) 1674 #endif 1675 { 1676 static int bad_free_warn = -1; 1677 if (bad_free_warn == -1) { 1678 dTHX; 1679 char *pbf = PerlEnv_getenv("PERL_BADFREE"); 1680 bad_free_warn = (pbf) ? atoi(pbf) : 1; 1681 } 1682 if (!bad_free_warn) 1683 return Nullch; 1684 #ifdef RCHECK 1685 #ifdef PERL_CORE 1686 { 1687 dTHX; 1688 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC)) 1689 Perl_warner(aTHX_ WARN_MALLOC, "%srealloc() %signored", 1690 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "), 1691 ovp->ov_rmagic == RMAGIC - 1 1692 ? "of freed memory " : ""); 1693 } 1694 #else 1695 warn("%srealloc() %signored", 1696 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "), 1697 ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : ""); 1698 #endif 1699 #else 1700 #ifdef PERL_CORE 1701 { 1702 dTHX; 1703 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC)) 1704 Perl_warner(aTHX_ WARN_MALLOC, "%s", 1705 "Bad realloc() ignored"); 1706 } 1707 #else 1708 warn("%s", "Bad realloc() ignored"); 1709 #endif 1710 #endif 1711 return Nullch; /* sanity */ 1712 } 1713 1714 onb = BUCKET_SIZE_REAL(bucket); 1715 /* 1716 * avoid the copy if same size block. 1717 * We are not agressive with boundary cases. Note that it might 1718 * (for a small number of cases) give false negative if 1719 * both new size and old one are in the bucket for 1720 * FIRST_BIG_POW2, but the new one is near the lower end. 1721 * 1722 * We do not try to go to 1.5 times smaller bucket so far. 1723 */ 1724 if (nbytes > onb) incr = 1; 1725 else { 1726 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING 1727 if ( /* This is a little bit pessimal if PACK_MALLOC: */ 1728 nbytes > ( (onb >> 1) - M_OVERHEAD ) 1729 # ifdef TWO_POT_OPTIMIZE 1730 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND ) 1731 # endif 1732 ) 1733 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */ 1734 prev_bucket = ( (bucket > MAX_PACKED + 1) 1735 ? bucket - BUCKETS_PER_POW2 1736 : bucket - 1); 1737 if (nbytes > BUCKET_SIZE_REAL(prev_bucket)) 1738 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */ 1739 incr = 0; 1740 else incr = -1; 1741 } 1742 #ifdef STRESS_REALLOC 1743 goto hard_way; 1744 #endif 1745 if (incr == 0) { 1746 inplace_label: 1747 #ifdef RCHECK 1748 /* 1749 * Record new allocated size of block and 1750 * bound space with magic numbers. 1751 */ 1752 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) { 1753 int i, nb = ovp->ov_size + 1; 1754 1755 if ((i = nb & 3)) { 1756 i = 4 - i; 1757 while (i--) { 1758 ASSERT(*((char *)((caddr_t)ovp + nb - RSLOP + i)) == RMAGIC_C, "chunk's tail overwrite"); 1759 } 1760 } 1761 nb = (nb + 3) &~ 3; 1762 ASSERT(*(u_int *)((caddr_t)ovp + nb - RSLOP) == RMAGIC, "chunk's tail overwrite"); 1763 /* 1764 * Convert amount of memory requested into 1765 * closest block size stored in hash buckets 1766 * which satisfies request. Account for 1767 * space used per block for accounting. 1768 */ 1769 nbytes += M_OVERHEAD; 1770 ovp->ov_size = nbytes - 1; 1771 if ((i = nbytes & 3)) { 1772 i = 4 - i; 1773 while (i--) 1774 *((char *)((caddr_t)ovp + nbytes - RSLOP + i)) 1775 = RMAGIC_C; 1776 } 1777 nbytes = (nbytes + 3) &~ 3; 1778 *((u_int *)((caddr_t)ovp + nbytes - RSLOP)) = RMAGIC; 1779 } 1780 #endif 1781 res = cp; 1782 DEBUG_m(PerlIO_printf(Perl_debug_log, 1783 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n", 1784 PTR2UV(res),(unsigned long)(PL_an++), 1785 (long)size)); 1786 } else if (incr == 1 && (cp - M_OVERHEAD == last_op) 1787 && (onb > (1 << LOG_OF_MIN_ARENA))) { 1788 MEM_SIZE require, newarena = nbytes, pow; 1789 int shiftr; 1790 1791 POW2_OPTIMIZE_ADJUST(newarena); 1792 newarena = newarena + M_OVERHEAD; 1793 /* newarena = (newarena + 3) &~ 3; */ 1794 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA; 1795 pow = LOG_OF_MIN_ARENA + 1; 1796 /* apart from this loop, this is O(1) */ 1797 while (shiftr >>= 1) 1798 pow++; 1799 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2); 1800 require = newarena - onb - M_OVERHEAD; 1801 1802 MALLOC_LOCK; 1803 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */ 1804 && getpages_adjacent(require)) { 1805 #ifdef DEBUGGING_MSTATS 1806 nmalloc[bucket]--; 1807 nmalloc[pow * BUCKETS_PER_POW2]++; 1808 #endif 1809 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */ 1810 MALLOC_UNLOCK; 1811 goto inplace_label; 1812 } else { 1813 MALLOC_UNLOCK; 1814 goto hard_way; 1815 } 1816 } else { 1817 hard_way: 1818 DEBUG_m(PerlIO_printf(Perl_debug_log, 1819 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n", 1820 PTR2UV(cp),(unsigned long)(PL_an++), 1821 (long)size)); 1822 if ((res = (char*)Perl_malloc(nbytes)) == NULL) 1823 return (NULL); 1824 if (cp != res) /* common optimization */ 1825 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char); 1826 Perl_mfree(cp); 1827 } 1828 return ((Malloc_t)res); 1829 } 1830 1831 Malloc_t 1832 Perl_calloc(register size_t elements, register size_t size) 1833 { 1834 long sz = elements * size; 1835 Malloc_t p = Perl_malloc(sz); 1836 1837 if (p) { 1838 memset((void*)p, 0, sz); 1839 } 1840 return p; 1841 } 1842 1843 char * 1844 Perl_strdup(const char *s) 1845 { 1846 MEM_SIZE l = strlen(s); 1847 char *s1 = (char *)Perl_malloc(l+1); 1848 1849 Copy(s, s1, (MEM_SIZE)(l+1), char); 1850 return s1; 1851 } 1852 1853 #ifdef PERL_CORE 1854 int 1855 Perl_putenv(char *a) 1856 { 1857 /* Sometimes system's putenv conflicts with my_setenv() - this is system 1858 malloc vs Perl's free(). */ 1859 dTHX; 1860 char *var; 1861 char *val = a; 1862 MEM_SIZE l; 1863 char buf[80]; 1864 1865 while (*val && *val != '=') 1866 val++; 1867 if (!*val) 1868 return -1; 1869 l = val - a; 1870 if (l < sizeof(buf)) 1871 var = buf; 1872 else 1873 var = Perl_malloc(l + 1); 1874 Copy(a, var, l, char); 1875 var[l + 1] = 0; 1876 my_setenv(var, val+1); 1877 if (var != buf) 1878 Perl_mfree(var); 1879 return 0; 1880 } 1881 # endif 1882 1883 MEM_SIZE 1884 Perl_malloced_size(void *p) 1885 { 1886 union overhead *ovp = (union overhead *) 1887 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT); 1888 int bucket = OV_INDEX(ovp); 1889 #ifdef RCHECK 1890 /* The caller wants to have a complete control over the chunk, 1891 disable the memory checking inside the chunk. */ 1892 if (bucket <= MAX_SHORT_BUCKET) { 1893 MEM_SIZE size = BUCKET_SIZE_REAL(bucket); 1894 ovp->ov_size = size + M_OVERHEAD - 1; 1895 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RSLOP)) = RMAGIC; 1896 } 1897 #endif 1898 return BUCKET_SIZE_REAL(bucket); 1899 } 1900 1901 # ifdef BUCKETS_ROOT2 1902 # define MIN_EVEN_REPORT 6 1903 # else 1904 # define MIN_EVEN_REPORT MIN_BUCKET 1905 # endif 1906 1907 int 1908 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level) 1909 { 1910 #ifdef DEBUGGING_MSTATS 1911 register int i, j; 1912 register union overhead *p; 1913 struct chunk_chain_s* nextchain; 1914 1915 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd 1916 = buf->totfree = buf->total = buf->total_chain = 0; 1917 1918 buf->minbucket = MIN_BUCKET; 1919 MALLOC_LOCK; 1920 for (i = MIN_BUCKET ; i < NBUCKETS; i++) { 1921 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) 1922 ; 1923 if (i < buflen) { 1924 buf->nfree[i] = j; 1925 buf->ntotal[i] = nmalloc[i]; 1926 } 1927 buf->totfree += j * BUCKET_SIZE_REAL(i); 1928 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i); 1929 if (nmalloc[i]) { 1930 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i); 1931 buf->topbucket = i; 1932 } 1933 } 1934 nextchain = chunk_chain; 1935 while (nextchain) { 1936 buf->total_chain += nextchain->size; 1937 nextchain = nextchain->next; 1938 } 1939 buf->total_sbrk = goodsbrk + sbrk_slack; 1940 buf->sbrks = sbrks; 1941 buf->sbrk_good = sbrk_good; 1942 buf->sbrk_slack = sbrk_slack; 1943 buf->start_slack = start_slack; 1944 buf->sbrked_remains = sbrked_remains; 1945 MALLOC_UNLOCK; 1946 buf->nbuckets = NBUCKETS; 1947 if (level) { 1948 for (i = MIN_BUCKET ; i < NBUCKETS; i++) { 1949 if (i >= buflen) 1950 break; 1951 buf->bucket_mem_size[i] = BUCKET_SIZE(i); 1952 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i); 1953 } 1954 } 1955 #endif /* defined DEBUGGING_MSTATS */ 1956 return 0; /* XXX unused */ 1957 } 1958 /* 1959 * mstats - print out statistics about malloc 1960 * 1961 * Prints two lines of numbers, one showing the length of the free list 1962 * for each size category, the second showing the number of mallocs - 1963 * frees for each size category. 1964 */ 1965 void 1966 Perl_dump_mstats(pTHX_ char *s) 1967 { 1968 #ifdef DEBUGGING_MSTATS 1969 register int i; 1970 perl_mstats_t buffer; 1971 UV nf[NBUCKETS]; 1972 UV nt[NBUCKETS]; 1973 1974 buffer.nfree = nf; 1975 buffer.ntotal = nt; 1976 get_mstats(&buffer, NBUCKETS, 0); 1977 1978 if (s) 1979 PerlIO_printf(Perl_error_log, 1980 "Memory allocation statistics %s (buckets %"IVdf"(%"IVdf")..%"IVdf"(%"IVdf")\n", 1981 s, 1982 (IV)BUCKET_SIZE_REAL(MIN_BUCKET), 1983 (IV)BUCKET_SIZE(MIN_BUCKET), 1984 (IV)BUCKET_SIZE_REAL(buffer.topbucket), 1985 (IV)BUCKET_SIZE(buffer.topbucket)); 1986 PerlIO_printf(Perl_error_log, "%8"IVdf" free:", buffer.totfree); 1987 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) { 1988 PerlIO_printf(Perl_error_log, 1989 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) 1990 ? " %5"UVuf 1991 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)), 1992 buffer.nfree[i]); 1993 } 1994 #ifdef BUCKETS_ROOT2 1995 PerlIO_printf(Perl_error_log, "\n\t "); 1996 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) { 1997 PerlIO_printf(Perl_error_log, 1998 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) 1999 ? " %5"UVuf 2000 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)), 2001 buffer.nfree[i]); 2002 } 2003 #endif 2004 PerlIO_printf(Perl_error_log, "\n%8"IVdf" used:", buffer.total - buffer.totfree); 2005 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) { 2006 PerlIO_printf(Perl_error_log, 2007 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) 2008 ? " %5"IVdf 2009 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)), 2010 buffer.ntotal[i] - buffer.nfree[i]); 2011 } 2012 #ifdef BUCKETS_ROOT2 2013 PerlIO_printf(Perl_error_log, "\n\t "); 2014 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) { 2015 PerlIO_printf(Perl_error_log, 2016 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) 2017 ? " %5"IVdf 2018 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)), 2019 buffer.ntotal[i] - buffer.nfree[i]); 2020 } 2021 #endif 2022 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %"IVdf"/%"IVdf":%"IVdf". Odd ends: pad+heads+chain+tail: %"IVdf"+%"IVdf"+%"IVdf"+%"IVdf".\n", 2023 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good, 2024 buffer.sbrk_slack, buffer.start_slack, 2025 buffer.total_chain, buffer.sbrked_remains); 2026 #endif /* DEBUGGING_MSTATS */ 2027 } 2028 #endif /* lint */ 2029 2030 #ifdef USE_PERL_SBRK 2031 2032 # if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) || defined(PURIFY) 2033 # define PERL_SBRK_VIA_MALLOC 2034 # endif 2035 2036 # ifdef PERL_SBRK_VIA_MALLOC 2037 2038 /* it may seem schizophrenic to use perl's malloc and let it call system */ 2039 /* malloc, the reason for that is only the 3.2 version of the OS that had */ 2040 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */ 2041 /* end to the cores */ 2042 2043 # ifndef SYSTEM_ALLOC 2044 # define SYSTEM_ALLOC(a) malloc(a) 2045 # endif 2046 # ifndef SYSTEM_ALLOC_ALIGNMENT 2047 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES 2048 # endif 2049 2050 # endif /* PERL_SBRK_VIA_MALLOC */ 2051 2052 static IV Perl_sbrk_oldchunk; 2053 static long Perl_sbrk_oldsize; 2054 2055 # define PERLSBRK_32_K (1<<15) 2056 # define PERLSBRK_64_K (1<<16) 2057 2058 Malloc_t 2059 Perl_sbrk(int size) 2060 { 2061 IV got; 2062 int small, reqsize; 2063 2064 if (!size) return 0; 2065 #ifdef PERL_CORE 2066 reqsize = size; /* just for the DEBUG_m statement */ 2067 #endif 2068 #ifdef PACK_MALLOC 2069 size = (size + 0x7ff) & ~0x7ff; 2070 #endif 2071 if (size <= Perl_sbrk_oldsize) { 2072 got = Perl_sbrk_oldchunk; 2073 Perl_sbrk_oldchunk += size; 2074 Perl_sbrk_oldsize -= size; 2075 } else { 2076 if (size >= PERLSBRK_32_K) { 2077 small = 0; 2078 } else { 2079 size = PERLSBRK_64_K; 2080 small = 1; 2081 } 2082 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT 2083 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT; 2084 # endif 2085 got = (IV)SYSTEM_ALLOC(size); 2086 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT 2087 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1); 2088 # endif 2089 if (small) { 2090 /* Chunk is small, register the rest for future allocs. */ 2091 Perl_sbrk_oldchunk = got + reqsize; 2092 Perl_sbrk_oldsize = size - reqsize; 2093 } 2094 } 2095 2096 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n", 2097 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got))); 2098 2099 return (void *)got; 2100 } 2101 2102 #endif /* ! defined USE_PERL_SBRK */ 2103