1 #include <common.h> 2 3 #ifdef CONFIG_SANDBOX 4 #define DEBUG 5 #endif 6 7 #if 0 /* Moved to malloc.h */ 8 /* ---------- To make a malloc.h, start cutting here ------------ */ 9 10 /* 11 A version of malloc/free/realloc written by Doug Lea and released to the 12 public domain. Send questions/comments/complaints/performance data 13 to dl@cs.oswego.edu 14 15 * VERSION 2.6.6 Sun Mar 5 19:10:03 2000 Doug Lea (dl at gee) 16 17 Note: There may be an updated version of this malloc obtainable at 18 ftp://g.oswego.edu/pub/misc/malloc.c 19 Check before installing! 20 21 * Why use this malloc? 22 23 This is not the fastest, most space-conserving, most portable, or 24 most tunable malloc ever written. However it is among the fastest 25 while also being among the most space-conserving, portable and tunable. 26 Consistent balance across these factors results in a good general-purpose 27 allocator. For a high-level description, see 28 http://g.oswego.edu/dl/html/malloc.html 29 30 * Synopsis of public routines 31 32 (Much fuller descriptions are contained in the program documentation below.) 33 34 malloc(size_t n); 35 Return a pointer to a newly allocated chunk of at least n bytes, or null 36 if no space is available. 37 free(Void_t* p); 38 Release the chunk of memory pointed to by p, or no effect if p is null. 39 realloc(Void_t* p, size_t n); 40 Return a pointer to a chunk of size n that contains the same data 41 as does chunk p up to the minimum of (n, p's size) bytes, or null 42 if no space is available. The returned pointer may or may not be 43 the same as p. If p is null, equivalent to malloc. Unless the 44 #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a 45 size argument of zero (re)allocates a minimum-sized chunk. 46 memalign(size_t alignment, size_t n); 47 Return a pointer to a newly allocated chunk of n bytes, aligned 48 in accord with the alignment argument, which must be a power of 49 two. 50 valloc(size_t n); 51 Equivalent to memalign(pagesize, n), where pagesize is the page 52 size of the system (or as near to this as can be figured out from 53 all the includes/defines below.) 54 pvalloc(size_t n); 55 Equivalent to valloc(minimum-page-that-holds(n)), that is, 56 round up n to nearest pagesize. 57 calloc(size_t unit, size_t quantity); 58 Returns a pointer to quantity * unit bytes, with all locations 59 set to zero. 60 cfree(Void_t* p); 61 Equivalent to free(p). 62 malloc_trim(size_t pad); 63 Release all but pad bytes of freed top-most memory back 64 to the system. Return 1 if successful, else 0. 65 malloc_usable_size(Void_t* p); 66 Report the number usable allocated bytes associated with allocated 67 chunk p. This may or may not report more bytes than were requested, 68 due to alignment and minimum size constraints. 69 malloc_stats(); 70 Prints brief summary statistics. 71 mallinfo() 72 Returns (by copy) a struct containing various summary statistics. 73 mallopt(int parameter_number, int parameter_value) 74 Changes one of the tunable parameters described below. Returns 75 1 if successful in changing the parameter, else 0. 76 77 * Vital statistics: 78 79 Alignment: 8-byte 80 8 byte alignment is currently hardwired into the design. This 81 seems to suffice for all current machines and C compilers. 82 83 Assumed pointer representation: 4 or 8 bytes 84 Code for 8-byte pointers is untested by me but has worked 85 reliably by Wolfram Gloger, who contributed most of the 86 changes supporting this. 87 88 Assumed size_t representation: 4 or 8 bytes 89 Note that size_t is allowed to be 4 bytes even if pointers are 8. 90 91 Minimum overhead per allocated chunk: 4 or 8 bytes 92 Each malloced chunk has a hidden overhead of 4 bytes holding size 93 and status information. 94 95 Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead) 96 8-byte ptrs: 24/32 bytes (including, 4/8 overhead) 97 98 When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte 99 ptrs but 4 byte size) or 24 (for 8/8) additional bytes are 100 needed; 4 (8) for a trailing size field 101 and 8 (16) bytes for free list pointers. Thus, the minimum 102 allocatable size is 16/24/32 bytes. 103 104 Even a request for zero bytes (i.e., malloc(0)) returns a 105 pointer to something of the minimum allocatable size. 106 107 Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes 108 8-byte size_t: 2^63 - 16 bytes 109 110 It is assumed that (possibly signed) size_t bit values suffice to 111 represent chunk sizes. `Possibly signed' is due to the fact 112 that `size_t' may be defined on a system as either a signed or 113 an unsigned type. To be conservative, values that would appear 114 as negative numbers are avoided. 115 Requests for sizes with a negative sign bit when the request 116 size is treaded as a long will return null. 117 118 Maximum overhead wastage per allocated chunk: normally 15 bytes 119 120 Alignnment demands, plus the minimum allocatable size restriction 121 make the normal worst-case wastage 15 bytes (i.e., up to 15 122 more bytes will be allocated than were requested in malloc), with 123 two exceptions: 124 1. Because requests for zero bytes allocate non-zero space, 125 the worst case wastage for a request of zero bytes is 24 bytes. 126 2. For requests >= mmap_threshold that are serviced via 127 mmap(), the worst case wastage is 8 bytes plus the remainder 128 from a system page (the minimal mmap unit); typically 4096 bytes. 129 130 * Limitations 131 132 Here are some features that are NOT currently supported 133 134 * No user-definable hooks for callbacks and the like. 135 * No automated mechanism for fully checking that all accesses 136 to malloced memory stay within their bounds. 137 * No support for compaction. 138 139 * Synopsis of compile-time options: 140 141 People have reported using previous versions of this malloc on all 142 versions of Unix, sometimes by tweaking some of the defines 143 below. It has been tested most extensively on Solaris and 144 Linux. It is also reported to work on WIN32 platforms. 145 People have also reported adapting this malloc for use in 146 stand-alone embedded systems. 147 148 The implementation is in straight, hand-tuned ANSI C. Among other 149 consequences, it uses a lot of macros. Because of this, to be at 150 all usable, this code should be compiled using an optimizing compiler 151 (for example gcc -O2) that can simplify expressions and control 152 paths. 153 154 __STD_C (default: derived from C compiler defines) 155 Nonzero if using ANSI-standard C compiler, a C++ compiler, or 156 a C compiler sufficiently close to ANSI to get away with it. 157 DEBUG (default: NOT defined) 158 Define to enable debugging. Adds fairly extensive assertion-based 159 checking to help track down memory errors, but noticeably slows down 160 execution. 161 REALLOC_ZERO_BYTES_FREES (default: NOT defined) 162 Define this if you think that realloc(p, 0) should be equivalent 163 to free(p). Otherwise, since malloc returns a unique pointer for 164 malloc(0), so does realloc(p, 0). 165 HAVE_MEMCPY (default: defined) 166 Define if you are not otherwise using ANSI STD C, but still 167 have memcpy and memset in your C library and want to use them. 168 Otherwise, simple internal versions are supplied. 169 USE_MEMCPY (default: 1 if HAVE_MEMCPY is defined, 0 otherwise) 170 Define as 1 if you want the C library versions of memset and 171 memcpy called in realloc and calloc (otherwise macro versions are used). 172 At least on some platforms, the simple macro versions usually 173 outperform libc versions. 174 HAVE_MMAP (default: defined as 1) 175 Define to non-zero to optionally make malloc() use mmap() to 176 allocate very large blocks. 177 HAVE_MREMAP (default: defined as 0 unless Linux libc set) 178 Define to non-zero to optionally make realloc() use mremap() to 179 reallocate very large blocks. 180 malloc_getpagesize (default: derived from system #includes) 181 Either a constant or routine call returning the system page size. 182 HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined) 183 Optionally define if you are on a system with a /usr/include/malloc.h 184 that declares struct mallinfo. It is not at all necessary to 185 define this even if you do, but will ensure consistency. 186 INTERNAL_SIZE_T (default: size_t) 187 Define to a 32-bit type (probably `unsigned int') if you are on a 188 64-bit machine, yet do not want or need to allow malloc requests of 189 greater than 2^31 to be handled. This saves space, especially for 190 very small chunks. 191 INTERNAL_LINUX_C_LIB (default: NOT defined) 192 Defined only when compiled as part of Linux libc. 193 Also note that there is some odd internal name-mangling via defines 194 (for example, internally, `malloc' is named `mALLOc') needed 195 when compiling in this case. These look funny but don't otherwise 196 affect anything. 197 WIN32 (default: undefined) 198 Define this on MS win (95, nt) platforms to compile in sbrk emulation. 199 LACKS_UNISTD_H (default: undefined if not WIN32) 200 Define this if your system does not have a <unistd.h>. 201 LACKS_SYS_PARAM_H (default: undefined if not WIN32) 202 Define this if your system does not have a <sys/param.h>. 203 MORECORE (default: sbrk) 204 The name of the routine to call to obtain more memory from the system. 205 MORECORE_FAILURE (default: -1) 206 The value returned upon failure of MORECORE. 207 MORECORE_CLEARS (default 1) 208 true (1) if the routine mapped to MORECORE zeroes out memory (which 209 holds for sbrk). 210 DEFAULT_TRIM_THRESHOLD 211 DEFAULT_TOP_PAD 212 DEFAULT_MMAP_THRESHOLD 213 DEFAULT_MMAP_MAX 214 Default values of tunable parameters (described in detail below) 215 controlling interaction with host system routines (sbrk, mmap, etc). 216 These values may also be changed dynamically via mallopt(). The 217 preset defaults are those that give best performance for typical 218 programs/systems. 219 USE_DL_PREFIX (default: undefined) 220 Prefix all public routines with the string 'dl'. Useful to 221 quickly avoid procedure declaration conflicts and linker symbol 222 conflicts with existing memory allocation routines. 223 224 225 */ 226 227 228 229 /* Preliminaries */ 230 231 #ifndef __STD_C 232 #ifdef __STDC__ 233 #define __STD_C 1 234 #else 235 #if __cplusplus 236 #define __STD_C 1 237 #else 238 #define __STD_C 0 239 #endif /*__cplusplus*/ 240 #endif /*__STDC__*/ 241 #endif /*__STD_C*/ 242 243 #ifndef Void_t 244 #if (__STD_C || defined(WIN32)) 245 #define Void_t void 246 #else 247 #define Void_t char 248 #endif 249 #endif /*Void_t*/ 250 251 #if __STD_C 252 #include <stddef.h> /* for size_t */ 253 #else 254 #include <sys/types.h> 255 #endif 256 257 #ifdef __cplusplus 258 extern "C" { 259 #endif 260 261 #include <stdio.h> /* needed for malloc_stats */ 262 263 264 /* 265 Compile-time options 266 */ 267 268 269 /* 270 Debugging: 271 272 Because freed chunks may be overwritten with link fields, this 273 malloc will often die when freed memory is overwritten by user 274 programs. This can be very effective (albeit in an annoying way) 275 in helping track down dangling pointers. 276 277 If you compile with -DDEBUG, a number of assertion checks are 278 enabled that will catch more memory errors. You probably won't be 279 able to make much sense of the actual assertion errors, but they 280 should help you locate incorrectly overwritten memory. The 281 checking is fairly extensive, and will slow down execution 282 noticeably. Calling malloc_stats or mallinfo with DEBUG set will 283 attempt to check every non-mmapped allocated and free chunk in the 284 course of computing the summmaries. (By nature, mmapped regions 285 cannot be checked very much automatically.) 286 287 Setting DEBUG may also be helpful if you are trying to modify 288 this code. The assertions in the check routines spell out in more 289 detail the assumptions and invariants underlying the algorithms. 290 291 */ 292 293 /* 294 INTERNAL_SIZE_T is the word-size used for internal bookkeeping 295 of chunk sizes. On a 64-bit machine, you can reduce malloc 296 overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int' 297 at the expense of not being able to handle requests greater than 298 2^31. This limitation is hardly ever a concern; you are encouraged 299 to set this. However, the default version is the same as size_t. 300 */ 301 302 #ifndef INTERNAL_SIZE_T 303 #define INTERNAL_SIZE_T size_t 304 #endif 305 306 /* 307 REALLOC_ZERO_BYTES_FREES should be set if a call to 308 realloc with zero bytes should be the same as a call to free. 309 Some people think it should. Otherwise, since this malloc 310 returns a unique pointer for malloc(0), so does realloc(p, 0). 311 */ 312 313 314 /* #define REALLOC_ZERO_BYTES_FREES */ 315 316 317 /* 318 WIN32 causes an emulation of sbrk to be compiled in 319 mmap-based options are not currently supported in WIN32. 320 */ 321 322 /* #define WIN32 */ 323 #ifdef WIN32 324 #define MORECORE wsbrk 325 #define HAVE_MMAP 0 326 327 #define LACKS_UNISTD_H 328 #define LACKS_SYS_PARAM_H 329 330 /* 331 Include 'windows.h' to get the necessary declarations for the 332 Microsoft Visual C++ data structures and routines used in the 'sbrk' 333 emulation. 334 335 Define WIN32_LEAN_AND_MEAN so that only the essential Microsoft 336 Visual C++ header files are included. 337 */ 338 #define WIN32_LEAN_AND_MEAN 339 #include <windows.h> 340 #endif 341 342 343 /* 344 HAVE_MEMCPY should be defined if you are not otherwise using 345 ANSI STD C, but still have memcpy and memset in your C library 346 and want to use them in calloc and realloc. Otherwise simple 347 macro versions are defined here. 348 349 USE_MEMCPY should be defined as 1 if you actually want to 350 have memset and memcpy called. People report that the macro 351 versions are often enough faster than libc versions on many 352 systems that it is better to use them. 353 354 */ 355 356 #define HAVE_MEMCPY 357 358 #ifndef USE_MEMCPY 359 #ifdef HAVE_MEMCPY 360 #define USE_MEMCPY 1 361 #else 362 #define USE_MEMCPY 0 363 #endif 364 #endif 365 366 #if (__STD_C || defined(HAVE_MEMCPY)) 367 368 #if __STD_C 369 void* memset(void*, int, size_t); 370 void* memcpy(void*, const void*, size_t); 371 #else 372 #ifdef WIN32 373 /* On Win32 platforms, 'memset()' and 'memcpy()' are already declared in */ 374 /* 'windows.h' */ 375 #else 376 Void_t* memset(); 377 Void_t* memcpy(); 378 #endif 379 #endif 380 #endif 381 382 #if USE_MEMCPY 383 384 /* The following macros are only invoked with (2n+1)-multiples of 385 INTERNAL_SIZE_T units, with a positive integer n. This is exploited 386 for fast inline execution when n is small. */ 387 388 #define MALLOC_ZERO(charp, nbytes) \ 389 do { \ 390 INTERNAL_SIZE_T mzsz = (nbytes); \ 391 if(mzsz <= 9*sizeof(mzsz)) { \ 392 INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp); \ 393 if(mzsz >= 5*sizeof(mzsz)) { *mz++ = 0; \ 394 *mz++ = 0; \ 395 if(mzsz >= 7*sizeof(mzsz)) { *mz++ = 0; \ 396 *mz++ = 0; \ 397 if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0; \ 398 *mz++ = 0; }}} \ 399 *mz++ = 0; \ 400 *mz++ = 0; \ 401 *mz = 0; \ 402 } else memset((charp), 0, mzsz); \ 403 } while(0) 404 405 #define MALLOC_COPY(dest,src,nbytes) \ 406 do { \ 407 INTERNAL_SIZE_T mcsz = (nbytes); \ 408 if(mcsz <= 9*sizeof(mcsz)) { \ 409 INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src); \ 410 INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest); \ 411 if(mcsz >= 5*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ 412 *mcdst++ = *mcsrc++; \ 413 if(mcsz >= 7*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ 414 *mcdst++ = *mcsrc++; \ 415 if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ 416 *mcdst++ = *mcsrc++; }}} \ 417 *mcdst++ = *mcsrc++; \ 418 *mcdst++ = *mcsrc++; \ 419 *mcdst = *mcsrc ; \ 420 } else memcpy(dest, src, mcsz); \ 421 } while(0) 422 423 #else /* !USE_MEMCPY */ 424 425 /* Use Duff's device for good zeroing/copying performance. */ 426 427 #define MALLOC_ZERO(charp, nbytes) \ 428 do { \ 429 INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp); \ 430 long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ 431 if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ 432 switch (mctmp) { \ 433 case 0: for(;;) { *mzp++ = 0; \ 434 case 7: *mzp++ = 0; \ 435 case 6: *mzp++ = 0; \ 436 case 5: *mzp++ = 0; \ 437 case 4: *mzp++ = 0; \ 438 case 3: *mzp++ = 0; \ 439 case 2: *mzp++ = 0; \ 440 case 1: *mzp++ = 0; if(mcn <= 0) break; mcn--; } \ 441 } \ 442 } while(0) 443 444 #define MALLOC_COPY(dest,src,nbytes) \ 445 do { \ 446 INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \ 447 INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \ 448 long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ 449 if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ 450 switch (mctmp) { \ 451 case 0: for(;;) { *mcdst++ = *mcsrc++; \ 452 case 7: *mcdst++ = *mcsrc++; \ 453 case 6: *mcdst++ = *mcsrc++; \ 454 case 5: *mcdst++ = *mcsrc++; \ 455 case 4: *mcdst++ = *mcsrc++; \ 456 case 3: *mcdst++ = *mcsrc++; \ 457 case 2: *mcdst++ = *mcsrc++; \ 458 case 1: *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; } \ 459 } \ 460 } while(0) 461 462 #endif 463 464 465 /* 466 Define HAVE_MMAP to optionally make malloc() use mmap() to 467 allocate very large blocks. These will be returned to the 468 operating system immediately after a free(). 469 */ 470 471 #ifndef HAVE_MMAP 472 #define HAVE_MMAP 1 473 #endif 474 475 /* 476 Define HAVE_MREMAP to make realloc() use mremap() to re-allocate 477 large blocks. This is currently only possible on Linux with 478 kernel versions newer than 1.3.77. 479 */ 480 481 #ifndef HAVE_MREMAP 482 #ifdef INTERNAL_LINUX_C_LIB 483 #define HAVE_MREMAP 1 484 #else 485 #define HAVE_MREMAP 0 486 #endif 487 #endif 488 489 #if HAVE_MMAP 490 491 #include <unistd.h> 492 #include <fcntl.h> 493 #include <sys/mman.h> 494 495 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) 496 #define MAP_ANONYMOUS MAP_ANON 497 #endif 498 499 #endif /* HAVE_MMAP */ 500 501 /* 502 Access to system page size. To the extent possible, this malloc 503 manages memory from the system in page-size units. 504 505 The following mechanics for getpagesize were adapted from 506 bsd/gnu getpagesize.h 507 */ 508 509 #ifndef LACKS_UNISTD_H 510 # include <unistd.h> 511 #endif 512 513 #ifndef malloc_getpagesize 514 # ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */ 515 # ifndef _SC_PAGE_SIZE 516 # define _SC_PAGE_SIZE _SC_PAGESIZE 517 # endif 518 # endif 519 # ifdef _SC_PAGE_SIZE 520 # define malloc_getpagesize sysconf(_SC_PAGE_SIZE) 521 # else 522 # if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE) 523 extern size_t getpagesize(); 524 # define malloc_getpagesize getpagesize() 525 # else 526 # ifdef WIN32 527 # define malloc_getpagesize (4096) /* TBD: Use 'GetSystemInfo' instead */ 528 # else 529 # ifndef LACKS_SYS_PARAM_H 530 # include <sys/param.h> 531 # endif 532 # ifdef EXEC_PAGESIZE 533 # define malloc_getpagesize EXEC_PAGESIZE 534 # else 535 # ifdef NBPG 536 # ifndef CLSIZE 537 # define malloc_getpagesize NBPG 538 # else 539 # define malloc_getpagesize (NBPG * CLSIZE) 540 # endif 541 # else 542 # ifdef NBPC 543 # define malloc_getpagesize NBPC 544 # else 545 # ifdef PAGESIZE 546 # define malloc_getpagesize PAGESIZE 547 # else 548 # define malloc_getpagesize (4096) /* just guess */ 549 # endif 550 # endif 551 # endif 552 # endif 553 # endif 554 # endif 555 # endif 556 #endif 557 558 559 /* 560 561 This version of malloc supports the standard SVID/XPG mallinfo 562 routine that returns a struct containing the same kind of 563 information you can get from malloc_stats. It should work on 564 any SVID/XPG compliant system that has a /usr/include/malloc.h 565 defining struct mallinfo. (If you'd like to install such a thing 566 yourself, cut out the preliminary declarations as described above 567 and below and save them in a malloc.h file. But there's no 568 compelling reason to bother to do this.) 569 570 The main declaration needed is the mallinfo struct that is returned 571 (by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a 572 bunch of fields, most of which are not even meaningful in this 573 version of malloc. Some of these fields are are instead filled by 574 mallinfo() with other numbers that might possibly be of interest. 575 576 HAVE_USR_INCLUDE_MALLOC_H should be set if you have a 577 /usr/include/malloc.h file that includes a declaration of struct 578 mallinfo. If so, it is included; else an SVID2/XPG2 compliant 579 version is declared below. These must be precisely the same for 580 mallinfo() to work. 581 582 */ 583 584 /* #define HAVE_USR_INCLUDE_MALLOC_H */ 585 586 #if HAVE_USR_INCLUDE_MALLOC_H 587 #include "/usr/include/malloc.h" 588 #else 589 590 /* SVID2/XPG mallinfo structure */ 591 592 struct mallinfo { 593 int arena; /* total space allocated from system */ 594 int ordblks; /* number of non-inuse chunks */ 595 int smblks; /* unused -- always zero */ 596 int hblks; /* number of mmapped regions */ 597 int hblkhd; /* total space in mmapped regions */ 598 int usmblks; /* unused -- always zero */ 599 int fsmblks; /* unused -- always zero */ 600 int uordblks; /* total allocated space */ 601 int fordblks; /* total non-inuse space */ 602 int keepcost; /* top-most, releasable (via malloc_trim) space */ 603 }; 604 605 /* SVID2/XPG mallopt options */ 606 607 #define M_MXFAST 1 /* UNUSED in this malloc */ 608 #define M_NLBLKS 2 /* UNUSED in this malloc */ 609 #define M_GRAIN 3 /* UNUSED in this malloc */ 610 #define M_KEEP 4 /* UNUSED in this malloc */ 611 612 #endif 613 614 /* mallopt options that actually do something */ 615 616 #define M_TRIM_THRESHOLD -1 617 #define M_TOP_PAD -2 618 #define M_MMAP_THRESHOLD -3 619 #define M_MMAP_MAX -4 620 621 622 #ifndef DEFAULT_TRIM_THRESHOLD 623 #define DEFAULT_TRIM_THRESHOLD (128 * 1024) 624 #endif 625 626 /* 627 M_TRIM_THRESHOLD is the maximum amount of unused top-most memory 628 to keep before releasing via malloc_trim in free(). 629 630 Automatic trimming is mainly useful in long-lived programs. 631 Because trimming via sbrk can be slow on some systems, and can 632 sometimes be wasteful (in cases where programs immediately 633 afterward allocate more large chunks) the value should be high 634 enough so that your overall system performance would improve by 635 releasing. 636 637 The trim threshold and the mmap control parameters (see below) 638 can be traded off with one another. Trimming and mmapping are 639 two different ways of releasing unused memory back to the 640 system. Between these two, it is often possible to keep 641 system-level demands of a long-lived program down to a bare 642 minimum. For example, in one test suite of sessions measuring 643 the XF86 X server on Linux, using a trim threshold of 128K and a 644 mmap threshold of 192K led to near-minimal long term resource 645 consumption. 646 647 If you are using this malloc in a long-lived program, it should 648 pay to experiment with these values. As a rough guide, you 649 might set to a value close to the average size of a process 650 (program) running on your system. Releasing this much memory 651 would allow such a process to run in memory. Generally, it's 652 worth it to tune for trimming rather tham memory mapping when a 653 program undergoes phases where several large chunks are 654 allocated and released in ways that can reuse each other's 655 storage, perhaps mixed with phases where there are no such 656 chunks at all. And in well-behaved long-lived programs, 657 controlling release of large blocks via trimming versus mapping 658 is usually faster. 659 660 However, in most programs, these parameters serve mainly as 661 protection against the system-level effects of carrying around 662 massive amounts of unneeded memory. Since frequent calls to 663 sbrk, mmap, and munmap otherwise degrade performance, the default 664 parameters are set to relatively high values that serve only as 665 safeguards. 666 667 The default trim value is high enough to cause trimming only in 668 fairly extreme (by current memory consumption standards) cases. 669 It must be greater than page size to have any useful effect. To 670 disable trimming completely, you can set to (unsigned long)(-1); 671 672 673 */ 674 675 676 #ifndef DEFAULT_TOP_PAD 677 #define DEFAULT_TOP_PAD (0) 678 #endif 679 680 /* 681 M_TOP_PAD is the amount of extra `padding' space to allocate or 682 retain whenever sbrk is called. It is used in two ways internally: 683 684 * When sbrk is called to extend the top of the arena to satisfy 685 a new malloc request, this much padding is added to the sbrk 686 request. 687 688 * When malloc_trim is called automatically from free(), 689 it is used as the `pad' argument. 690 691 In both cases, the actual amount of padding is rounded 692 so that the end of the arena is always a system page boundary. 693 694 The main reason for using padding is to avoid calling sbrk so 695 often. Having even a small pad greatly reduces the likelihood 696 that nearly every malloc request during program start-up (or 697 after trimming) will invoke sbrk, which needlessly wastes 698 time. 699 700 Automatic rounding-up to page-size units is normally sufficient 701 to avoid measurable overhead, so the default is 0. However, in 702 systems where sbrk is relatively slow, it can pay to increase 703 this value, at the expense of carrying around more memory than 704 the program needs. 705 706 */ 707 708 709 #ifndef DEFAULT_MMAP_THRESHOLD 710 #define DEFAULT_MMAP_THRESHOLD (128 * 1024) 711 #endif 712 713 /* 714 715 M_MMAP_THRESHOLD is the request size threshold for using mmap() 716 to service a request. Requests of at least this size that cannot 717 be allocated using already-existing space will be serviced via mmap. 718 (If enough normal freed space already exists it is used instead.) 719 720 Using mmap segregates relatively large chunks of memory so that 721 they can be individually obtained and released from the host 722 system. A request serviced through mmap is never reused by any 723 other request (at least not directly; the system may just so 724 happen to remap successive requests to the same locations). 725 726 Segregating space in this way has the benefit that mmapped space 727 can ALWAYS be individually released back to the system, which 728 helps keep the system level memory demands of a long-lived 729 program low. Mapped memory can never become `locked' between 730 other chunks, as can happen with normally allocated chunks, which 731 menas that even trimming via malloc_trim would not release them. 732 733 However, it has the disadvantages that: 734 735 1. The space cannot be reclaimed, consolidated, and then 736 used to service later requests, as happens with normal chunks. 737 2. It can lead to more wastage because of mmap page alignment 738 requirements 739 3. It causes malloc performance to be more dependent on host 740 system memory management support routines which may vary in 741 implementation quality and may impose arbitrary 742 limitations. Generally, servicing a request via normal 743 malloc steps is faster than going through a system's mmap. 744 745 All together, these considerations should lead you to use mmap 746 only for relatively large requests. 747 748 749 */ 750 751 752 #ifndef DEFAULT_MMAP_MAX 753 #if HAVE_MMAP 754 #define DEFAULT_MMAP_MAX (64) 755 #else 756 #define DEFAULT_MMAP_MAX (0) 757 #endif 758 #endif 759 760 /* 761 M_MMAP_MAX is the maximum number of requests to simultaneously 762 service using mmap. This parameter exists because: 763 764 1. Some systems have a limited number of internal tables for 765 use by mmap. 766 2. In most systems, overreliance on mmap can degrade overall 767 performance. 768 3. If a program allocates many large regions, it is probably 769 better off using normal sbrk-based allocation routines that 770 can reclaim and reallocate normal heap memory. Using a 771 small value allows transition into this mode after the 772 first few allocations. 773 774 Setting to 0 disables all use of mmap. If HAVE_MMAP is not set, 775 the default value is 0, and attempts to set it to non-zero values 776 in mallopt will fail. 777 */ 778 779 780 /* 781 USE_DL_PREFIX will prefix all public routines with the string 'dl'. 782 Useful to quickly avoid procedure declaration conflicts and linker 783 symbol conflicts with existing memory allocation routines. 784 785 */ 786 787 /* #define USE_DL_PREFIX */ 788 789 790 /* 791 792 Special defines for linux libc 793 794 Except when compiled using these special defines for Linux libc 795 using weak aliases, this malloc is NOT designed to work in 796 multithreaded applications. No semaphores or other concurrency 797 control are provided to ensure that multiple malloc or free calls 798 don't run at the same time, which could be disasterous. A single 799 semaphore could be used across malloc, realloc, and free (which is 800 essentially the effect of the linux weak alias approach). It would 801 be hard to obtain finer granularity. 802 803 */ 804 805 806 #ifdef INTERNAL_LINUX_C_LIB 807 808 #if __STD_C 809 810 Void_t * __default_morecore_init (ptrdiff_t); 811 Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init; 812 813 #else 814 815 Void_t * __default_morecore_init (); 816 Void_t *(*__morecore)() = __default_morecore_init; 817 818 #endif 819 820 #define MORECORE (*__morecore) 821 #define MORECORE_FAILURE 0 822 #define MORECORE_CLEARS 1 823 824 #else /* INTERNAL_LINUX_C_LIB */ 825 826 #if __STD_C 827 extern Void_t* sbrk(ptrdiff_t); 828 #else 829 extern Void_t* sbrk(); 830 #endif 831 832 #ifndef MORECORE 833 #define MORECORE sbrk 834 #endif 835 836 #ifndef MORECORE_FAILURE 837 #define MORECORE_FAILURE -1 838 #endif 839 840 #ifndef MORECORE_CLEARS 841 #define MORECORE_CLEARS 1 842 #endif 843 844 #endif /* INTERNAL_LINUX_C_LIB */ 845 846 #if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__) 847 848 #define cALLOc __libc_calloc 849 #define fREe __libc_free 850 #define mALLOc __libc_malloc 851 #define mEMALIGn __libc_memalign 852 #define rEALLOc __libc_realloc 853 #define vALLOc __libc_valloc 854 #define pvALLOc __libc_pvalloc 855 #define mALLINFo __libc_mallinfo 856 #define mALLOPt __libc_mallopt 857 858 #pragma weak calloc = __libc_calloc 859 #pragma weak free = __libc_free 860 #pragma weak cfree = __libc_free 861 #pragma weak malloc = __libc_malloc 862 #pragma weak memalign = __libc_memalign 863 #pragma weak realloc = __libc_realloc 864 #pragma weak valloc = __libc_valloc 865 #pragma weak pvalloc = __libc_pvalloc 866 #pragma weak mallinfo = __libc_mallinfo 867 #pragma weak mallopt = __libc_mallopt 868 869 #else 870 871 #ifdef USE_DL_PREFIX 872 #define cALLOc dlcalloc 873 #define fREe dlfree 874 #define mALLOc dlmalloc 875 #define mEMALIGn dlmemalign 876 #define rEALLOc dlrealloc 877 #define vALLOc dlvalloc 878 #define pvALLOc dlpvalloc 879 #define mALLINFo dlmallinfo 880 #define mALLOPt dlmallopt 881 #else /* USE_DL_PREFIX */ 882 #define cALLOc calloc 883 #define fREe free 884 #define mALLOc malloc 885 #define mEMALIGn memalign 886 #define rEALLOc realloc 887 #define vALLOc valloc 888 #define pvALLOc pvalloc 889 #define mALLINFo mallinfo 890 #define mALLOPt mallopt 891 #endif /* USE_DL_PREFIX */ 892 893 #endif 894 895 /* Public routines */ 896 897 #if __STD_C 898 899 Void_t* mALLOc(size_t); 900 void fREe(Void_t*); 901 Void_t* rEALLOc(Void_t*, size_t); 902 Void_t* mEMALIGn(size_t, size_t); 903 Void_t* vALLOc(size_t); 904 Void_t* pvALLOc(size_t); 905 Void_t* cALLOc(size_t, size_t); 906 void cfree(Void_t*); 907 int malloc_trim(size_t); 908 size_t malloc_usable_size(Void_t*); 909 void malloc_stats(); 910 int mALLOPt(int, int); 911 struct mallinfo mALLINFo(void); 912 #else 913 Void_t* mALLOc(); 914 void fREe(); 915 Void_t* rEALLOc(); 916 Void_t* mEMALIGn(); 917 Void_t* vALLOc(); 918 Void_t* pvALLOc(); 919 Void_t* cALLOc(); 920 void cfree(); 921 int malloc_trim(); 922 size_t malloc_usable_size(); 923 void malloc_stats(); 924 int mALLOPt(); 925 struct mallinfo mALLINFo(); 926 #endif 927 928 929 #ifdef __cplusplus 930 }; /* end of extern "C" */ 931 #endif 932 933 /* ---------- To make a malloc.h, end cutting here ------------ */ 934 #endif /* 0 */ /* Moved to malloc.h */ 935 936 #include <malloc.h> 937 #include <asm/io.h> 938 939 #ifdef DEBUG 940 #if __STD_C 941 static void malloc_update_mallinfo (void); 942 void malloc_stats (void); 943 #else 944 static void malloc_update_mallinfo (); 945 void malloc_stats(); 946 #endif 947 #endif /* DEBUG */ 948 949 DECLARE_GLOBAL_DATA_PTR; 950 951 /* 952 Emulation of sbrk for WIN32 953 All code within the ifdef WIN32 is untested by me. 954 955 Thanks to Martin Fong and others for supplying this. 956 */ 957 958 959 #ifdef WIN32 960 961 #define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \ 962 ~(malloc_getpagesize-1)) 963 #define AlignPage64K(add) (((add) + (0x10000 - 1)) & ~(0x10000 - 1)) 964 965 /* resrve 64MB to insure large contiguous space */ 966 #define RESERVED_SIZE (1024*1024*64) 967 #define NEXT_SIZE (2048*1024) 968 #define TOP_MEMORY ((unsigned long)2*1024*1024*1024) 969 970 struct GmListElement; 971 typedef struct GmListElement GmListElement; 972 973 struct GmListElement 974 { 975 GmListElement* next; 976 void* base; 977 }; 978 979 static GmListElement* head = 0; 980 static unsigned int gNextAddress = 0; 981 static unsigned int gAddressBase = 0; 982 static unsigned int gAllocatedSize = 0; 983 984 static 985 GmListElement* makeGmListElement (void* bas) 986 { 987 GmListElement* this; 988 this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement)); 989 assert (this); 990 if (this) 991 { 992 this->base = bas; 993 this->next = head; 994 head = this; 995 } 996 return this; 997 } 998 999 void gcleanup () 1000 { 1001 BOOL rval; 1002 assert ( (head == NULL) || (head->base == (void*)gAddressBase)); 1003 if (gAddressBase && (gNextAddress - gAddressBase)) 1004 { 1005 rval = VirtualFree ((void*)gAddressBase, 1006 gNextAddress - gAddressBase, 1007 MEM_DECOMMIT); 1008 assert (rval); 1009 } 1010 while (head) 1011 { 1012 GmListElement* next = head->next; 1013 rval = VirtualFree (head->base, 0, MEM_RELEASE); 1014 assert (rval); 1015 LocalFree (head); 1016 head = next; 1017 } 1018 } 1019 1020 static 1021 void* findRegion (void* start_address, unsigned long size) 1022 { 1023 MEMORY_BASIC_INFORMATION info; 1024 if (size >= TOP_MEMORY) return NULL; 1025 1026 while ((unsigned long)start_address + size < TOP_MEMORY) 1027 { 1028 VirtualQuery (start_address, &info, sizeof (info)); 1029 if ((info.State == MEM_FREE) && (info.RegionSize >= size)) 1030 return start_address; 1031 else 1032 { 1033 /* Requested region is not available so see if the */ 1034 /* next region is available. Set 'start_address' */ 1035 /* to the next region and call 'VirtualQuery()' */ 1036 /* again. */ 1037 1038 start_address = (char*)info.BaseAddress + info.RegionSize; 1039 1040 /* Make sure we start looking for the next region */ 1041 /* on the *next* 64K boundary. Otherwise, even if */ 1042 /* the new region is free according to */ 1043 /* 'VirtualQuery()', the subsequent call to */ 1044 /* 'VirtualAlloc()' (which follows the call to */ 1045 /* this routine in 'wsbrk()') will round *down* */ 1046 /* the requested address to a 64K boundary which */ 1047 /* we already know is an address in the */ 1048 /* unavailable region. Thus, the subsequent call */ 1049 /* to 'VirtualAlloc()' will fail and bring us back */ 1050 /* here, causing us to go into an infinite loop. */ 1051 1052 start_address = 1053 (void *) AlignPage64K((unsigned long) start_address); 1054 } 1055 } 1056 return NULL; 1057 1058 } 1059 1060 1061 void* wsbrk (long size) 1062 { 1063 void* tmp; 1064 if (size > 0) 1065 { 1066 if (gAddressBase == 0) 1067 { 1068 gAllocatedSize = max (RESERVED_SIZE, AlignPage (size)); 1069 gNextAddress = gAddressBase = 1070 (unsigned int)VirtualAlloc (NULL, gAllocatedSize, 1071 MEM_RESERVE, PAGE_NOACCESS); 1072 } else if (AlignPage (gNextAddress + size) > (gAddressBase + 1073 gAllocatedSize)) 1074 { 1075 long new_size = max (NEXT_SIZE, AlignPage (size)); 1076 void* new_address = (void*)(gAddressBase+gAllocatedSize); 1077 do 1078 { 1079 new_address = findRegion (new_address, new_size); 1080 1081 if (new_address == 0) 1082 return (void*)-1; 1083 1084 gAddressBase = gNextAddress = 1085 (unsigned int)VirtualAlloc (new_address, new_size, 1086 MEM_RESERVE, PAGE_NOACCESS); 1087 /* repeat in case of race condition */ 1088 /* The region that we found has been snagged */ 1089 /* by another thread */ 1090 } 1091 while (gAddressBase == 0); 1092 1093 assert (new_address == (void*)gAddressBase); 1094 1095 gAllocatedSize = new_size; 1096 1097 if (!makeGmListElement ((void*)gAddressBase)) 1098 return (void*)-1; 1099 } 1100 if ((size + gNextAddress) > AlignPage (gNextAddress)) 1101 { 1102 void* res; 1103 res = VirtualAlloc ((void*)AlignPage (gNextAddress), 1104 (size + gNextAddress - 1105 AlignPage (gNextAddress)), 1106 MEM_COMMIT, PAGE_READWRITE); 1107 if (res == 0) 1108 return (void*)-1; 1109 } 1110 tmp = (void*)gNextAddress; 1111 gNextAddress = (unsigned int)tmp + size; 1112 return tmp; 1113 } 1114 else if (size < 0) 1115 { 1116 unsigned int alignedGoal = AlignPage (gNextAddress + size); 1117 /* Trim by releasing the virtual memory */ 1118 if (alignedGoal >= gAddressBase) 1119 { 1120 VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal, 1121 MEM_DECOMMIT); 1122 gNextAddress = gNextAddress + size; 1123 return (void*)gNextAddress; 1124 } 1125 else 1126 { 1127 VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase, 1128 MEM_DECOMMIT); 1129 gNextAddress = gAddressBase; 1130 return (void*)-1; 1131 } 1132 } 1133 else 1134 { 1135 return (void*)gNextAddress; 1136 } 1137 } 1138 1139 #endif 1140 1141 1142 1143 /* 1144 Type declarations 1145 */ 1146 1147 1148 struct malloc_chunk 1149 { 1150 INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */ 1151 INTERNAL_SIZE_T size; /* Size in bytes, including overhead. */ 1152 struct malloc_chunk* fd; /* double links -- used only if free. */ 1153 struct malloc_chunk* bk; 1154 } __attribute__((__may_alias__)) ; 1155 1156 typedef struct malloc_chunk* mchunkptr; 1157 1158 /* 1159 1160 malloc_chunk details: 1161 1162 (The following includes lightly edited explanations by Colin Plumb.) 1163 1164 Chunks of memory are maintained using a `boundary tag' method as 1165 described in e.g., Knuth or Standish. (See the paper by Paul 1166 Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a 1167 survey of such techniques.) Sizes of free chunks are stored both 1168 in the front of each chunk and at the end. This makes 1169 consolidating fragmented chunks into bigger chunks very fast. The 1170 size fields also hold bits representing whether chunks are free or 1171 in use. 1172 1173 An allocated chunk looks like this: 1174 1175 1176 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1177 | Size of previous chunk, if allocated | | 1178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1179 | Size of chunk, in bytes |P| 1180 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1181 | User data starts here... . 1182 . . 1183 . (malloc_usable_space() bytes) . 1184 . | 1185 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1186 | Size of chunk | 1187 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1188 1189 1190 Where "chunk" is the front of the chunk for the purpose of most of 1191 the malloc code, but "mem" is the pointer that is returned to the 1192 user. "Nextchunk" is the beginning of the next contiguous chunk. 1193 1194 Chunks always begin on even word boundries, so the mem portion 1195 (which is returned to the user) is also on an even word boundary, and 1196 thus double-word aligned. 1197 1198 Free chunks are stored in circular doubly-linked lists, and look like this: 1199 1200 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1201 | Size of previous chunk | 1202 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1203 `head:' | Size of chunk, in bytes |P| 1204 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1205 | Forward pointer to next chunk in list | 1206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1207 | Back pointer to previous chunk in list | 1208 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1209 | Unused space (may be 0 bytes long) . 1210 . . 1211 . | 1212 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1213 `foot:' | Size of chunk, in bytes | 1214 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1215 1216 The P (PREV_INUSE) bit, stored in the unused low-order bit of the 1217 chunk size (which is always a multiple of two words), is an in-use 1218 bit for the *previous* chunk. If that bit is *clear*, then the 1219 word before the current chunk size contains the previous chunk 1220 size, and can be used to find the front of the previous chunk. 1221 (The very first chunk allocated always has this bit set, 1222 preventing access to non-existent (or non-owned) memory.) 1223 1224 Note that the `foot' of the current chunk is actually represented 1225 as the prev_size of the NEXT chunk. (This makes it easier to 1226 deal with alignments etc). 1227 1228 The two exceptions to all this are 1229 1230 1. The special chunk `top', which doesn't bother using the 1231 trailing size field since there is no 1232 next contiguous chunk that would have to index off it. (After 1233 initialization, `top' is forced to always exist. If it would 1234 become less than MINSIZE bytes long, it is replenished via 1235 malloc_extend_top.) 1236 1237 2. Chunks allocated via mmap, which have the second-lowest-order 1238 bit (IS_MMAPPED) set in their size fields. Because they are 1239 never merged or traversed from any other chunk, they have no 1240 foot size or inuse information. 1241 1242 Available chunks are kept in any of several places (all declared below): 1243 1244 * `av': An array of chunks serving as bin headers for consolidated 1245 chunks. Each bin is doubly linked. The bins are approximately 1246 proportionally (log) spaced. There are a lot of these bins 1247 (128). This may look excessive, but works very well in 1248 practice. All procedures maintain the invariant that no 1249 consolidated chunk physically borders another one. Chunks in 1250 bins are kept in size order, with ties going to the 1251 approximately least recently used chunk. 1252 1253 The chunks in each bin are maintained in decreasing sorted order by 1254 size. This is irrelevant for the small bins, which all contain 1255 the same-sized chunks, but facilitates best-fit allocation for 1256 larger chunks. (These lists are just sequential. Keeping them in 1257 order almost never requires enough traversal to warrant using 1258 fancier ordered data structures.) Chunks of the same size are 1259 linked with the most recently freed at the front, and allocations 1260 are taken from the back. This results in LRU or FIFO allocation 1261 order, which tends to give each chunk an equal opportunity to be 1262 consolidated with adjacent freed chunks, resulting in larger free 1263 chunks and less fragmentation. 1264 1265 * `top': The top-most available chunk (i.e., the one bordering the 1266 end of available memory) is treated specially. It is never 1267 included in any bin, is used only if no other chunk is 1268 available, and is released back to the system if it is very 1269 large (see M_TRIM_THRESHOLD). 1270 1271 * `last_remainder': A bin holding only the remainder of the 1272 most recently split (non-top) chunk. This bin is checked 1273 before other non-fitting chunks, so as to provide better 1274 locality for runs of sequentially allocated chunks. 1275 1276 * Implicitly, through the host system's memory mapping tables. 1277 If supported, requests greater than a threshold are usually 1278 serviced via calls to mmap, and then later released via munmap. 1279 1280 */ 1281 1282 /* sizes, alignments */ 1283 1284 #define SIZE_SZ (sizeof(INTERNAL_SIZE_T)) 1285 #define MALLOC_ALIGNMENT (SIZE_SZ + SIZE_SZ) 1286 #define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1) 1287 #define MINSIZE (sizeof(struct malloc_chunk)) 1288 1289 /* conversion from malloc headers to user pointers, and back */ 1290 1291 #define chunk2mem(p) ((Void_t*)((char*)(p) + 2*SIZE_SZ)) 1292 #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ)) 1293 1294 /* pad request bytes into a usable size */ 1295 1296 #define request2size(req) \ 1297 (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \ 1298 (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \ 1299 (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK))) 1300 1301 /* Check if m has acceptable alignment */ 1302 1303 #define aligned_OK(m) (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0) 1304 1305 1306 1307 1308 /* 1309 Physical chunk operations 1310 */ 1311 1312 1313 /* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */ 1314 1315 #define PREV_INUSE 0x1 1316 1317 /* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */ 1318 1319 #define IS_MMAPPED 0x2 1320 1321 /* Bits to mask off when extracting size */ 1322 1323 #define SIZE_BITS (PREV_INUSE|IS_MMAPPED) 1324 1325 1326 /* Ptr to next physical malloc_chunk. */ 1327 1328 #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) )) 1329 1330 /* Ptr to previous physical malloc_chunk */ 1331 1332 #define prev_chunk(p)\ 1333 ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) )) 1334 1335 1336 /* Treat space at ptr + offset as a chunk */ 1337 1338 #define chunk_at_offset(p, s) ((mchunkptr)(((char*)(p)) + (s))) 1339 1340 1341 1342 1343 /* 1344 Dealing with use bits 1345 */ 1346 1347 /* extract p's inuse bit */ 1348 1349 #define inuse(p)\ 1350 ((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE) 1351 1352 /* extract inuse bit of previous chunk */ 1353 1354 #define prev_inuse(p) ((p)->size & PREV_INUSE) 1355 1356 /* check for mmap()'ed chunk */ 1357 1358 #define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED) 1359 1360 /* set/clear chunk as in use without otherwise disturbing */ 1361 1362 #define set_inuse(p)\ 1363 ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE 1364 1365 #define clear_inuse(p)\ 1366 ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE) 1367 1368 /* check/set/clear inuse bits in known places */ 1369 1370 #define inuse_bit_at_offset(p, s)\ 1371 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE) 1372 1373 #define set_inuse_bit_at_offset(p, s)\ 1374 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE) 1375 1376 #define clear_inuse_bit_at_offset(p, s)\ 1377 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE)) 1378 1379 1380 1381 1382 /* 1383 Dealing with size fields 1384 */ 1385 1386 /* Get size, ignoring use bits */ 1387 1388 #define chunksize(p) ((p)->size & ~(SIZE_BITS)) 1389 1390 /* Set size at head, without disturbing its use bit */ 1391 1392 #define set_head_size(p, s) ((p)->size = (((p)->size & PREV_INUSE) | (s))) 1393 1394 /* Set size/use ignoring previous bits in header */ 1395 1396 #define set_head(p, s) ((p)->size = (s)) 1397 1398 /* Set size at footer (only when chunk is not in use) */ 1399 1400 #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s)) 1401 1402 1403 1404 1405 1406 /* 1407 Bins 1408 1409 The bins, `av_' are an array of pairs of pointers serving as the 1410 heads of (initially empty) doubly-linked lists of chunks, laid out 1411 in a way so that each pair can be treated as if it were in a 1412 malloc_chunk. (This way, the fd/bk offsets for linking bin heads 1413 and chunks are the same). 1414 1415 Bins for sizes < 512 bytes contain chunks of all the same size, spaced 1416 8 bytes apart. Larger bins are approximately logarithmically 1417 spaced. (See the table below.) The `av_' array is never mentioned 1418 directly in the code, but instead via bin access macros. 1419 1420 Bin layout: 1421 1422 64 bins of size 8 1423 32 bins of size 64 1424 16 bins of size 512 1425 8 bins of size 4096 1426 4 bins of size 32768 1427 2 bins of size 262144 1428 1 bin of size what's left 1429 1430 There is actually a little bit of slop in the numbers in bin_index 1431 for the sake of speed. This makes no difference elsewhere. 1432 1433 The special chunks `top' and `last_remainder' get their own bins, 1434 (this is implemented via yet more trickery with the av_ array), 1435 although `top' is never properly linked to its bin since it is 1436 always handled specially. 1437 1438 */ 1439 1440 #define NAV 128 /* number of bins */ 1441 1442 typedef struct malloc_chunk* mbinptr; 1443 1444 /* access macros */ 1445 1446 #define bin_at(i) ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ)) 1447 #define next_bin(b) ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr))) 1448 #define prev_bin(b) ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr))) 1449 1450 /* 1451 The first 2 bins are never indexed. The corresponding av_ cells are instead 1452 used for bookkeeping. This is not to save space, but to simplify 1453 indexing, maintain locality, and avoid some initialization tests. 1454 */ 1455 1456 #define top (av_[2]) /* The topmost chunk */ 1457 #define last_remainder (bin_at(1)) /* remainder from last split */ 1458 1459 1460 /* 1461 Because top initially points to its own bin with initial 1462 zero size, thus forcing extension on the first malloc request, 1463 we avoid having any special code in malloc to check whether 1464 it even exists yet. But we still need to in malloc_extend_top. 1465 */ 1466 1467 #define initial_top ((mchunkptr)(bin_at(0))) 1468 1469 /* Helper macro to initialize bins */ 1470 1471 #define IAV(i) bin_at(i), bin_at(i) 1472 1473 static mbinptr av_[NAV * 2 + 2] = { 1474 NULL, NULL, 1475 IAV(0), IAV(1), IAV(2), IAV(3), IAV(4), IAV(5), IAV(6), IAV(7), 1476 IAV(8), IAV(9), IAV(10), IAV(11), IAV(12), IAV(13), IAV(14), IAV(15), 1477 IAV(16), IAV(17), IAV(18), IAV(19), IAV(20), IAV(21), IAV(22), IAV(23), 1478 IAV(24), IAV(25), IAV(26), IAV(27), IAV(28), IAV(29), IAV(30), IAV(31), 1479 IAV(32), IAV(33), IAV(34), IAV(35), IAV(36), IAV(37), IAV(38), IAV(39), 1480 IAV(40), IAV(41), IAV(42), IAV(43), IAV(44), IAV(45), IAV(46), IAV(47), 1481 IAV(48), IAV(49), IAV(50), IAV(51), IAV(52), IAV(53), IAV(54), IAV(55), 1482 IAV(56), IAV(57), IAV(58), IAV(59), IAV(60), IAV(61), IAV(62), IAV(63), 1483 IAV(64), IAV(65), IAV(66), IAV(67), IAV(68), IAV(69), IAV(70), IAV(71), 1484 IAV(72), IAV(73), IAV(74), IAV(75), IAV(76), IAV(77), IAV(78), IAV(79), 1485 IAV(80), IAV(81), IAV(82), IAV(83), IAV(84), IAV(85), IAV(86), IAV(87), 1486 IAV(88), IAV(89), IAV(90), IAV(91), IAV(92), IAV(93), IAV(94), IAV(95), 1487 IAV(96), IAV(97), IAV(98), IAV(99), IAV(100), IAV(101), IAV(102), IAV(103), 1488 IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111), 1489 IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119), 1490 IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127) 1491 }; 1492 1493 #ifdef CONFIG_NEEDS_MANUAL_RELOC 1494 static void malloc_bin_reloc(void) 1495 { 1496 mbinptr *p = &av_[2]; 1497 size_t i; 1498 1499 for (i = 2; i < ARRAY_SIZE(av_); ++i, ++p) 1500 *p = (mbinptr)((ulong)*p + gd->reloc_off); 1501 } 1502 #else 1503 static inline void malloc_bin_reloc(void) {} 1504 #endif 1505 1506 ulong mem_malloc_start = 0; 1507 ulong mem_malloc_end = 0; 1508 ulong mem_malloc_brk = 0; 1509 1510 void *sbrk(ptrdiff_t increment) 1511 { 1512 ulong old = mem_malloc_brk; 1513 ulong new = old + increment; 1514 1515 /* 1516 * if we are giving memory back make sure we clear it out since 1517 * we set MORECORE_CLEARS to 1 1518 */ 1519 if (increment < 0) 1520 memset((void *)new, 0, -increment); 1521 1522 if ((new < mem_malloc_start) || (new > mem_malloc_end)) 1523 return (void *)MORECORE_FAILURE; 1524 1525 mem_malloc_brk = new; 1526 1527 return (void *)old; 1528 } 1529 1530 void mem_malloc_init(ulong start, ulong size) 1531 { 1532 mem_malloc_start = start; 1533 mem_malloc_end = start + size; 1534 mem_malloc_brk = start; 1535 1536 debug("using memory %#lx-%#lx for malloc()\n", mem_malloc_start, 1537 mem_malloc_end); 1538 1539 memset((void *)mem_malloc_start, 0, size); 1540 1541 malloc_bin_reloc(); 1542 } 1543 1544 /* field-extraction macros */ 1545 1546 #define first(b) ((b)->fd) 1547 #define last(b) ((b)->bk) 1548 1549 /* 1550 Indexing into bins 1551 */ 1552 1553 #define bin_index(sz) \ 1554 (((((unsigned long)(sz)) >> 9) == 0) ? (((unsigned long)(sz)) >> 3): \ 1555 ((((unsigned long)(sz)) >> 9) <= 4) ? 56 + (((unsigned long)(sz)) >> 6): \ 1556 ((((unsigned long)(sz)) >> 9) <= 20) ? 91 + (((unsigned long)(sz)) >> 9): \ 1557 ((((unsigned long)(sz)) >> 9) <= 84) ? 110 + (((unsigned long)(sz)) >> 12): \ 1558 ((((unsigned long)(sz)) >> 9) <= 340) ? 119 + (((unsigned long)(sz)) >> 15): \ 1559 ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \ 1560 126) 1561 /* 1562 bins for chunks < 512 are all spaced 8 bytes apart, and hold 1563 identically sized chunks. This is exploited in malloc. 1564 */ 1565 1566 #define MAX_SMALLBIN 63 1567 #define MAX_SMALLBIN_SIZE 512 1568 #define SMALLBIN_WIDTH 8 1569 1570 #define smallbin_index(sz) (((unsigned long)(sz)) >> 3) 1571 1572 /* 1573 Requests are `small' if both the corresponding and the next bin are small 1574 */ 1575 1576 #define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH) 1577 1578 1579 1580 /* 1581 To help compensate for the large number of bins, a one-level index 1582 structure is used for bin-by-bin searching. `binblocks' is a 1583 one-word bitvector recording whether groups of BINBLOCKWIDTH bins 1584 have any (possibly) non-empty bins, so they can be skipped over 1585 all at once during during traversals. The bits are NOT always 1586 cleared as soon as all bins in a block are empty, but instead only 1587 when all are noticed to be empty during traversal in malloc. 1588 */ 1589 1590 #define BINBLOCKWIDTH 4 /* bins per block */ 1591 1592 #define binblocks_r ((INTERNAL_SIZE_T)av_[1]) /* bitvector of nonempty blocks */ 1593 #define binblocks_w (av_[1]) 1594 1595 /* bin<->block macros */ 1596 1597 #define idx2binblock(ix) ((unsigned)1 << (ix / BINBLOCKWIDTH)) 1598 #define mark_binblock(ii) (binblocks_w = (mbinptr)(binblocks_r | idx2binblock(ii))) 1599 #define clear_binblock(ii) (binblocks_w = (mbinptr)(binblocks_r & ~(idx2binblock(ii)))) 1600 1601 1602 1603 1604 1605 /* Other static bookkeeping data */ 1606 1607 /* variables holding tunable values */ 1608 1609 static unsigned long trim_threshold = DEFAULT_TRIM_THRESHOLD; 1610 static unsigned long top_pad = DEFAULT_TOP_PAD; 1611 static unsigned int n_mmaps_max = DEFAULT_MMAP_MAX; 1612 static unsigned long mmap_threshold = DEFAULT_MMAP_THRESHOLD; 1613 1614 /* The first value returned from sbrk */ 1615 static char* sbrk_base = (char*)(-1); 1616 1617 /* The maximum memory obtained from system via sbrk */ 1618 static unsigned long max_sbrked_mem = 0; 1619 1620 /* The maximum via either sbrk or mmap */ 1621 static unsigned long max_total_mem = 0; 1622 1623 /* internal working copy of mallinfo */ 1624 static struct mallinfo current_mallinfo = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; 1625 1626 /* The total memory obtained from system via sbrk */ 1627 #define sbrked_mem (current_mallinfo.arena) 1628 1629 /* Tracking mmaps */ 1630 1631 #ifdef DEBUG 1632 static unsigned int n_mmaps = 0; 1633 #endif /* DEBUG */ 1634 static unsigned long mmapped_mem = 0; 1635 #if HAVE_MMAP 1636 static unsigned int max_n_mmaps = 0; 1637 static unsigned long max_mmapped_mem = 0; 1638 #endif 1639 1640 1641 1642 /* 1643 Debugging support 1644 */ 1645 1646 #ifdef DEBUG 1647 1648 1649 /* 1650 These routines make a number of assertions about the states 1651 of data structures that should be true at all times. If any 1652 are not true, it's very likely that a user program has somehow 1653 trashed memory. (It's also possible that there is a coding error 1654 in malloc. In which case, please report it!) 1655 */ 1656 1657 #if __STD_C 1658 static void do_check_chunk(mchunkptr p) 1659 #else 1660 static void do_check_chunk(p) mchunkptr p; 1661 #endif 1662 { 1663 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; 1664 1665 /* No checkable chunk is mmapped */ 1666 assert(!chunk_is_mmapped(p)); 1667 1668 /* Check for legal address ... */ 1669 assert((char*)p >= sbrk_base); 1670 if (p != top) 1671 assert((char*)p + sz <= (char*)top); 1672 else 1673 assert((char*)p + sz <= sbrk_base + sbrked_mem); 1674 1675 } 1676 1677 1678 #if __STD_C 1679 static void do_check_free_chunk(mchunkptr p) 1680 #else 1681 static void do_check_free_chunk(p) mchunkptr p; 1682 #endif 1683 { 1684 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; 1685 mchunkptr next = chunk_at_offset(p, sz); 1686 1687 do_check_chunk(p); 1688 1689 /* Check whether it claims to be free ... */ 1690 assert(!inuse(p)); 1691 1692 /* Unless a special marker, must have OK fields */ 1693 if ((long)sz >= (long)MINSIZE) 1694 { 1695 assert((sz & MALLOC_ALIGN_MASK) == 0); 1696 assert(aligned_OK(chunk2mem(p))); 1697 /* ... matching footer field */ 1698 assert(next->prev_size == sz); 1699 /* ... and is fully consolidated */ 1700 assert(prev_inuse(p)); 1701 assert (next == top || inuse(next)); 1702 1703 /* ... and has minimally sane links */ 1704 assert(p->fd->bk == p); 1705 assert(p->bk->fd == p); 1706 } 1707 else /* markers are always of size SIZE_SZ */ 1708 assert(sz == SIZE_SZ); 1709 } 1710 1711 #if __STD_C 1712 static void do_check_inuse_chunk(mchunkptr p) 1713 #else 1714 static void do_check_inuse_chunk(p) mchunkptr p; 1715 #endif 1716 { 1717 mchunkptr next = next_chunk(p); 1718 do_check_chunk(p); 1719 1720 /* Check whether it claims to be in use ... */ 1721 assert(inuse(p)); 1722 1723 /* ... and is surrounded by OK chunks. 1724 Since more things can be checked with free chunks than inuse ones, 1725 if an inuse chunk borders them and debug is on, it's worth doing them. 1726 */ 1727 if (!prev_inuse(p)) 1728 { 1729 mchunkptr prv = prev_chunk(p); 1730 assert(next_chunk(prv) == p); 1731 do_check_free_chunk(prv); 1732 } 1733 if (next == top) 1734 { 1735 assert(prev_inuse(next)); 1736 assert(chunksize(next) >= MINSIZE); 1737 } 1738 else if (!inuse(next)) 1739 do_check_free_chunk(next); 1740 1741 } 1742 1743 #if __STD_C 1744 static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s) 1745 #else 1746 static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s; 1747 #endif 1748 { 1749 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; 1750 long room = sz - s; 1751 1752 do_check_inuse_chunk(p); 1753 1754 /* Legal size ... */ 1755 assert((long)sz >= (long)MINSIZE); 1756 assert((sz & MALLOC_ALIGN_MASK) == 0); 1757 assert(room >= 0); 1758 assert(room < (long)MINSIZE); 1759 1760 /* ... and alignment */ 1761 assert(aligned_OK(chunk2mem(p))); 1762 1763 1764 /* ... and was allocated at front of an available chunk */ 1765 assert(prev_inuse(p)); 1766 1767 } 1768 1769 1770 #define check_free_chunk(P) do_check_free_chunk(P) 1771 #define check_inuse_chunk(P) do_check_inuse_chunk(P) 1772 #define check_chunk(P) do_check_chunk(P) 1773 #define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N) 1774 #else 1775 #define check_free_chunk(P) 1776 #define check_inuse_chunk(P) 1777 #define check_chunk(P) 1778 #define check_malloced_chunk(P,N) 1779 #endif 1780 1781 1782 1783 /* 1784 Macro-based internal utilities 1785 */ 1786 1787 1788 /* 1789 Linking chunks in bin lists. 1790 Call these only with variables, not arbitrary expressions, as arguments. 1791 */ 1792 1793 /* 1794 Place chunk p of size s in its bin, in size order, 1795 putting it ahead of others of same size. 1796 */ 1797 1798 1799 #define frontlink(P, S, IDX, BK, FD) \ 1800 { \ 1801 if (S < MAX_SMALLBIN_SIZE) \ 1802 { \ 1803 IDX = smallbin_index(S); \ 1804 mark_binblock(IDX); \ 1805 BK = bin_at(IDX); \ 1806 FD = BK->fd; \ 1807 P->bk = BK; \ 1808 P->fd = FD; \ 1809 FD->bk = BK->fd = P; \ 1810 } \ 1811 else \ 1812 { \ 1813 IDX = bin_index(S); \ 1814 BK = bin_at(IDX); \ 1815 FD = BK->fd; \ 1816 if (FD == BK) mark_binblock(IDX); \ 1817 else \ 1818 { \ 1819 while (FD != BK && S < chunksize(FD)) FD = FD->fd; \ 1820 BK = FD->bk; \ 1821 } \ 1822 P->bk = BK; \ 1823 P->fd = FD; \ 1824 FD->bk = BK->fd = P; \ 1825 } \ 1826 } 1827 1828 1829 /* take a chunk off a list */ 1830 1831 #define unlink(P, BK, FD) \ 1832 { \ 1833 BK = P->bk; \ 1834 FD = P->fd; \ 1835 FD->bk = BK; \ 1836 BK->fd = FD; \ 1837 } \ 1838 1839 /* Place p as the last remainder */ 1840 1841 #define link_last_remainder(P) \ 1842 { \ 1843 last_remainder->fd = last_remainder->bk = P; \ 1844 P->fd = P->bk = last_remainder; \ 1845 } 1846 1847 /* Clear the last_remainder bin */ 1848 1849 #define clear_last_remainder \ 1850 (last_remainder->fd = last_remainder->bk = last_remainder) 1851 1852 1853 1854 1855 1856 /* Routines dealing with mmap(). */ 1857 1858 #if HAVE_MMAP 1859 1860 #if __STD_C 1861 static mchunkptr mmap_chunk(size_t size) 1862 #else 1863 static mchunkptr mmap_chunk(size) size_t size; 1864 #endif 1865 { 1866 size_t page_mask = malloc_getpagesize - 1; 1867 mchunkptr p; 1868 1869 #ifndef MAP_ANONYMOUS 1870 static int fd = -1; 1871 #endif 1872 1873 if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */ 1874 1875 /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because 1876 * there is no following chunk whose prev_size field could be used. 1877 */ 1878 size = (size + SIZE_SZ + page_mask) & ~page_mask; 1879 1880 #ifdef MAP_ANONYMOUS 1881 p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, 1882 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 1883 #else /* !MAP_ANONYMOUS */ 1884 if (fd < 0) 1885 { 1886 fd = open("/dev/zero", O_RDWR); 1887 if(fd < 0) return 0; 1888 } 1889 p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 1890 #endif 1891 1892 if(p == (mchunkptr)-1) return 0; 1893 1894 n_mmaps++; 1895 if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps; 1896 1897 /* We demand that eight bytes into a page must be 8-byte aligned. */ 1898 assert(aligned_OK(chunk2mem(p))); 1899 1900 /* The offset to the start of the mmapped region is stored 1901 * in the prev_size field of the chunk; normally it is zero, 1902 * but that can be changed in memalign(). 1903 */ 1904 p->prev_size = 0; 1905 set_head(p, size|IS_MMAPPED); 1906 1907 mmapped_mem += size; 1908 if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) 1909 max_mmapped_mem = mmapped_mem; 1910 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) 1911 max_total_mem = mmapped_mem + sbrked_mem; 1912 return p; 1913 } 1914 1915 #if __STD_C 1916 static void munmap_chunk(mchunkptr p) 1917 #else 1918 static void munmap_chunk(p) mchunkptr p; 1919 #endif 1920 { 1921 INTERNAL_SIZE_T size = chunksize(p); 1922 int ret; 1923 1924 assert (chunk_is_mmapped(p)); 1925 assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem)); 1926 assert((n_mmaps > 0)); 1927 assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0); 1928 1929 n_mmaps--; 1930 mmapped_mem -= (size + p->prev_size); 1931 1932 ret = munmap((char *)p - p->prev_size, size + p->prev_size); 1933 1934 /* munmap returns non-zero on failure */ 1935 assert(ret == 0); 1936 } 1937 1938 #if HAVE_MREMAP 1939 1940 #if __STD_C 1941 static mchunkptr mremap_chunk(mchunkptr p, size_t new_size) 1942 #else 1943 static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size; 1944 #endif 1945 { 1946 size_t page_mask = malloc_getpagesize - 1; 1947 INTERNAL_SIZE_T offset = p->prev_size; 1948 INTERNAL_SIZE_T size = chunksize(p); 1949 char *cp; 1950 1951 assert (chunk_is_mmapped(p)); 1952 assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem)); 1953 assert((n_mmaps > 0)); 1954 assert(((size + offset) & (malloc_getpagesize-1)) == 0); 1955 1956 /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */ 1957 new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask; 1958 1959 cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1); 1960 1961 if (cp == (char *)-1) return 0; 1962 1963 p = (mchunkptr)(cp + offset); 1964 1965 assert(aligned_OK(chunk2mem(p))); 1966 1967 assert((p->prev_size == offset)); 1968 set_head(p, (new_size - offset)|IS_MMAPPED); 1969 1970 mmapped_mem -= size + offset; 1971 mmapped_mem += new_size; 1972 if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) 1973 max_mmapped_mem = mmapped_mem; 1974 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) 1975 max_total_mem = mmapped_mem + sbrked_mem; 1976 return p; 1977 } 1978 1979 #endif /* HAVE_MREMAP */ 1980 1981 #endif /* HAVE_MMAP */ 1982 1983 1984 1985 1986 /* 1987 Extend the top-most chunk by obtaining memory from system. 1988 Main interface to sbrk (but see also malloc_trim). 1989 */ 1990 1991 #if __STD_C 1992 static void malloc_extend_top(INTERNAL_SIZE_T nb) 1993 #else 1994 static void malloc_extend_top(nb) INTERNAL_SIZE_T nb; 1995 #endif 1996 { 1997 char* brk; /* return value from sbrk */ 1998 INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */ 1999 INTERNAL_SIZE_T correction; /* bytes for 2nd sbrk call */ 2000 char* new_brk; /* return of 2nd sbrk call */ 2001 INTERNAL_SIZE_T top_size; /* new size of top chunk */ 2002 2003 mchunkptr old_top = top; /* Record state of old top */ 2004 INTERNAL_SIZE_T old_top_size = chunksize(old_top); 2005 char* old_end = (char*)(chunk_at_offset(old_top, old_top_size)); 2006 2007 /* Pad request with top_pad plus minimal overhead */ 2008 2009 INTERNAL_SIZE_T sbrk_size = nb + top_pad + MINSIZE; 2010 unsigned long pagesz = malloc_getpagesize; 2011 2012 /* If not the first time through, round to preserve page boundary */ 2013 /* Otherwise, we need to correct to a page size below anyway. */ 2014 /* (We also correct below if an intervening foreign sbrk call.) */ 2015 2016 if (sbrk_base != (char*)(-1)) 2017 sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1); 2018 2019 brk = (char*)(MORECORE (sbrk_size)); 2020 2021 /* Fail if sbrk failed or if a foreign sbrk call killed our space */ 2022 if (brk == (char*)(MORECORE_FAILURE) || 2023 (brk < old_end && old_top != initial_top)) 2024 return; 2025 2026 sbrked_mem += sbrk_size; 2027 2028 if (brk == old_end) /* can just add bytes to current top */ 2029 { 2030 top_size = sbrk_size + old_top_size; 2031 set_head(top, top_size | PREV_INUSE); 2032 } 2033 else 2034 { 2035 if (sbrk_base == (char*)(-1)) /* First time through. Record base */ 2036 sbrk_base = brk; 2037 else /* Someone else called sbrk(). Count those bytes as sbrked_mem. */ 2038 sbrked_mem += brk - (char*)old_end; 2039 2040 /* Guarantee alignment of first new chunk made from this space */ 2041 front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK; 2042 if (front_misalign > 0) 2043 { 2044 correction = (MALLOC_ALIGNMENT) - front_misalign; 2045 brk += correction; 2046 } 2047 else 2048 correction = 0; 2049 2050 /* Guarantee the next brk will be at a page boundary */ 2051 2052 correction += ((((unsigned long)(brk + sbrk_size))+(pagesz-1)) & 2053 ~(pagesz - 1)) - ((unsigned long)(brk + sbrk_size)); 2054 2055 /* Allocate correction */ 2056 new_brk = (char*)(MORECORE (correction)); 2057 if (new_brk == (char*)(MORECORE_FAILURE)) return; 2058 2059 sbrked_mem += correction; 2060 2061 top = (mchunkptr)brk; 2062 top_size = new_brk - brk + correction; 2063 set_head(top, top_size | PREV_INUSE); 2064 2065 if (old_top != initial_top) 2066 { 2067 2068 /* There must have been an intervening foreign sbrk call. */ 2069 /* A double fencepost is necessary to prevent consolidation */ 2070 2071 /* If not enough space to do this, then user did something very wrong */ 2072 if (old_top_size < MINSIZE) 2073 { 2074 set_head(top, PREV_INUSE); /* will force null return from malloc */ 2075 return; 2076 } 2077 2078 /* Also keep size a multiple of MALLOC_ALIGNMENT */ 2079 old_top_size = (old_top_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK; 2080 set_head_size(old_top, old_top_size); 2081 chunk_at_offset(old_top, old_top_size )->size = 2082 SIZE_SZ|PREV_INUSE; 2083 chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size = 2084 SIZE_SZ|PREV_INUSE; 2085 /* If possible, release the rest. */ 2086 if (old_top_size >= MINSIZE) 2087 fREe(chunk2mem(old_top)); 2088 } 2089 } 2090 2091 if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem) 2092 max_sbrked_mem = sbrked_mem; 2093 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) 2094 max_total_mem = mmapped_mem + sbrked_mem; 2095 2096 /* We always land on a page boundary */ 2097 assert(((unsigned long)((char*)top + top_size) & (pagesz - 1)) == 0); 2098 } 2099 2100 2101 2102 2103 /* Main public routines */ 2104 2105 2106 /* 2107 Malloc Algorthim: 2108 2109 The requested size is first converted into a usable form, `nb'. 2110 This currently means to add 4 bytes overhead plus possibly more to 2111 obtain 8-byte alignment and/or to obtain a size of at least 2112 MINSIZE (currently 16 bytes), the smallest allocatable size. 2113 (All fits are considered `exact' if they are within MINSIZE bytes.) 2114 2115 From there, the first successful of the following steps is taken: 2116 2117 1. The bin corresponding to the request size is scanned, and if 2118 a chunk of exactly the right size is found, it is taken. 2119 2120 2. The most recently remaindered chunk is used if it is big 2121 enough. This is a form of (roving) first fit, used only in 2122 the absence of exact fits. Runs of consecutive requests use 2123 the remainder of the chunk used for the previous such request 2124 whenever possible. This limited use of a first-fit style 2125 allocation strategy tends to give contiguous chunks 2126 coextensive lifetimes, which improves locality and can reduce 2127 fragmentation in the long run. 2128 2129 3. Other bins are scanned in increasing size order, using a 2130 chunk big enough to fulfill the request, and splitting off 2131 any remainder. This search is strictly by best-fit; i.e., 2132 the smallest (with ties going to approximately the least 2133 recently used) chunk that fits is selected. 2134 2135 4. If large enough, the chunk bordering the end of memory 2136 (`top') is split off. (This use of `top' is in accord with 2137 the best-fit search rule. In effect, `top' is treated as 2138 larger (and thus less well fitting) than any other available 2139 chunk since it can be extended to be as large as necessary 2140 (up to system limitations). 2141 2142 5. If the request size meets the mmap threshold and the 2143 system supports mmap, and there are few enough currently 2144 allocated mmapped regions, and a call to mmap succeeds, 2145 the request is allocated via direct memory mapping. 2146 2147 6. Otherwise, the top of memory is extended by 2148 obtaining more space from the system (normally using sbrk, 2149 but definable to anything else via the MORECORE macro). 2150 Memory is gathered from the system (in system page-sized 2151 units) in a way that allows chunks obtained across different 2152 sbrk calls to be consolidated, but does not require 2153 contiguous memory. Thus, it should be safe to intersperse 2154 mallocs with other sbrk calls. 2155 2156 2157 All allocations are made from the the `lowest' part of any found 2158 chunk. (The implementation invariant is that prev_inuse is 2159 always true of any allocated chunk; i.e., that each allocated 2160 chunk borders either a previously allocated and still in-use chunk, 2161 or the base of its memory arena.) 2162 2163 */ 2164 2165 #if __STD_C 2166 Void_t* mALLOc(size_t bytes) 2167 #else 2168 Void_t* mALLOc(bytes) size_t bytes; 2169 #endif 2170 { 2171 mchunkptr victim; /* inspected/selected chunk */ 2172 INTERNAL_SIZE_T victim_size; /* its size */ 2173 int idx; /* index for bin traversal */ 2174 mbinptr bin; /* associated bin */ 2175 mchunkptr remainder; /* remainder from a split */ 2176 long remainder_size; /* its size */ 2177 int remainder_index; /* its bin index */ 2178 unsigned long block; /* block traverser bit */ 2179 int startidx; /* first bin of a traversed block */ 2180 mchunkptr fwd; /* misc temp for linking */ 2181 mchunkptr bck; /* misc temp for linking */ 2182 mbinptr q; /* misc temp */ 2183 2184 INTERNAL_SIZE_T nb; 2185 2186 #ifdef CONFIG_SYS_MALLOC_F_LEN 2187 if (gd && !(gd->flags & GD_FLG_RELOC)) { 2188 ulong new_ptr; 2189 void *ptr; 2190 2191 new_ptr = gd->malloc_ptr + bytes; 2192 if (new_ptr > gd->malloc_limit) 2193 panic("Out of pre-reloc memory"); 2194 ptr = map_sysmem(gd->malloc_base + gd->malloc_ptr, bytes); 2195 gd->malloc_ptr = ALIGN(new_ptr, sizeof(new_ptr)); 2196 return ptr; 2197 } 2198 #endif 2199 2200 /* check if mem_malloc_init() was run */ 2201 if ((mem_malloc_start == 0) && (mem_malloc_end == 0)) { 2202 /* not initialized yet */ 2203 return NULL; 2204 } 2205 2206 if ((long)bytes < 0) return NULL; 2207 2208 nb = request2size(bytes); /* padded request size; */ 2209 2210 /* Check for exact match in a bin */ 2211 2212 if (is_small_request(nb)) /* Faster version for small requests */ 2213 { 2214 idx = smallbin_index(nb); 2215 2216 /* No traversal or size check necessary for small bins. */ 2217 2218 q = bin_at(idx); 2219 victim = last(q); 2220 2221 /* Also scan the next one, since it would have a remainder < MINSIZE */ 2222 if (victim == q) 2223 { 2224 q = next_bin(q); 2225 victim = last(q); 2226 } 2227 if (victim != q) 2228 { 2229 victim_size = chunksize(victim); 2230 unlink(victim, bck, fwd); 2231 set_inuse_bit_at_offset(victim, victim_size); 2232 check_malloced_chunk(victim, nb); 2233 return chunk2mem(victim); 2234 } 2235 2236 idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */ 2237 2238 } 2239 else 2240 { 2241 idx = bin_index(nb); 2242 bin = bin_at(idx); 2243 2244 for (victim = last(bin); victim != bin; victim = victim->bk) 2245 { 2246 victim_size = chunksize(victim); 2247 remainder_size = victim_size - nb; 2248 2249 if (remainder_size >= (long)MINSIZE) /* too big */ 2250 { 2251 --idx; /* adjust to rescan below after checking last remainder */ 2252 break; 2253 } 2254 2255 else if (remainder_size >= 0) /* exact fit */ 2256 { 2257 unlink(victim, bck, fwd); 2258 set_inuse_bit_at_offset(victim, victim_size); 2259 check_malloced_chunk(victim, nb); 2260 return chunk2mem(victim); 2261 } 2262 } 2263 2264 ++idx; 2265 2266 } 2267 2268 /* Try to use the last split-off remainder */ 2269 2270 if ( (victim = last_remainder->fd) != last_remainder) 2271 { 2272 victim_size = chunksize(victim); 2273 remainder_size = victim_size - nb; 2274 2275 if (remainder_size >= (long)MINSIZE) /* re-split */ 2276 { 2277 remainder = chunk_at_offset(victim, nb); 2278 set_head(victim, nb | PREV_INUSE); 2279 link_last_remainder(remainder); 2280 set_head(remainder, remainder_size | PREV_INUSE); 2281 set_foot(remainder, remainder_size); 2282 check_malloced_chunk(victim, nb); 2283 return chunk2mem(victim); 2284 } 2285 2286 clear_last_remainder; 2287 2288 if (remainder_size >= 0) /* exhaust */ 2289 { 2290 set_inuse_bit_at_offset(victim, victim_size); 2291 check_malloced_chunk(victim, nb); 2292 return chunk2mem(victim); 2293 } 2294 2295 /* Else place in bin */ 2296 2297 frontlink(victim, victim_size, remainder_index, bck, fwd); 2298 } 2299 2300 /* 2301 If there are any possibly nonempty big-enough blocks, 2302 search for best fitting chunk by scanning bins in blockwidth units. 2303 */ 2304 2305 if ( (block = idx2binblock(idx)) <= binblocks_r) 2306 { 2307 2308 /* Get to the first marked block */ 2309 2310 if ( (block & binblocks_r) == 0) 2311 { 2312 /* force to an even block boundary */ 2313 idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH; 2314 block <<= 1; 2315 while ((block & binblocks_r) == 0) 2316 { 2317 idx += BINBLOCKWIDTH; 2318 block <<= 1; 2319 } 2320 } 2321 2322 /* For each possibly nonempty block ... */ 2323 for (;;) 2324 { 2325 startidx = idx; /* (track incomplete blocks) */ 2326 q = bin = bin_at(idx); 2327 2328 /* For each bin in this block ... */ 2329 do 2330 { 2331 /* Find and use first big enough chunk ... */ 2332 2333 for (victim = last(bin); victim != bin; victim = victim->bk) 2334 { 2335 victim_size = chunksize(victim); 2336 remainder_size = victim_size - nb; 2337 2338 if (remainder_size >= (long)MINSIZE) /* split */ 2339 { 2340 remainder = chunk_at_offset(victim, nb); 2341 set_head(victim, nb | PREV_INUSE); 2342 unlink(victim, bck, fwd); 2343 link_last_remainder(remainder); 2344 set_head(remainder, remainder_size | PREV_INUSE); 2345 set_foot(remainder, remainder_size); 2346 check_malloced_chunk(victim, nb); 2347 return chunk2mem(victim); 2348 } 2349 2350 else if (remainder_size >= 0) /* take */ 2351 { 2352 set_inuse_bit_at_offset(victim, victim_size); 2353 unlink(victim, bck, fwd); 2354 check_malloced_chunk(victim, nb); 2355 return chunk2mem(victim); 2356 } 2357 2358 } 2359 2360 bin = next_bin(bin); 2361 2362 } while ((++idx & (BINBLOCKWIDTH - 1)) != 0); 2363 2364 /* Clear out the block bit. */ 2365 2366 do /* Possibly backtrack to try to clear a partial block */ 2367 { 2368 if ((startidx & (BINBLOCKWIDTH - 1)) == 0) 2369 { 2370 av_[1] = (mbinptr)(binblocks_r & ~block); 2371 break; 2372 } 2373 --startidx; 2374 q = prev_bin(q); 2375 } while (first(q) == q); 2376 2377 /* Get to the next possibly nonempty block */ 2378 2379 if ( (block <<= 1) <= binblocks_r && (block != 0) ) 2380 { 2381 while ((block & binblocks_r) == 0) 2382 { 2383 idx += BINBLOCKWIDTH; 2384 block <<= 1; 2385 } 2386 } 2387 else 2388 break; 2389 } 2390 } 2391 2392 2393 /* Try to use top chunk */ 2394 2395 /* Require that there be a remainder, ensuring top always exists */ 2396 if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE) 2397 { 2398 2399 #if HAVE_MMAP 2400 /* If big and would otherwise need to extend, try to use mmap instead */ 2401 if ((unsigned long)nb >= (unsigned long)mmap_threshold && 2402 (victim = mmap_chunk(nb)) != 0) 2403 return chunk2mem(victim); 2404 #endif 2405 2406 /* Try to extend */ 2407 malloc_extend_top(nb); 2408 if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE) 2409 return NULL; /* propagate failure */ 2410 } 2411 2412 victim = top; 2413 set_head(victim, nb | PREV_INUSE); 2414 top = chunk_at_offset(victim, nb); 2415 set_head(top, remainder_size | PREV_INUSE); 2416 check_malloced_chunk(victim, nb); 2417 return chunk2mem(victim); 2418 2419 } 2420 2421 2422 2423 2424 /* 2425 2426 free() algorithm : 2427 2428 cases: 2429 2430 1. free(0) has no effect. 2431 2432 2. If the chunk was allocated via mmap, it is release via munmap(). 2433 2434 3. If a returned chunk borders the current high end of memory, 2435 it is consolidated into the top, and if the total unused 2436 topmost memory exceeds the trim threshold, malloc_trim is 2437 called. 2438 2439 4. Other chunks are consolidated as they arrive, and 2440 placed in corresponding bins. (This includes the case of 2441 consolidating with the current `last_remainder'). 2442 2443 */ 2444 2445 2446 #if __STD_C 2447 void fREe(Void_t* mem) 2448 #else 2449 void fREe(mem) Void_t* mem; 2450 #endif 2451 { 2452 mchunkptr p; /* chunk corresponding to mem */ 2453 INTERNAL_SIZE_T hd; /* its head field */ 2454 INTERNAL_SIZE_T sz; /* its size */ 2455 int idx; /* its bin index */ 2456 mchunkptr next; /* next contiguous chunk */ 2457 INTERNAL_SIZE_T nextsz; /* its size */ 2458 INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */ 2459 mchunkptr bck; /* misc temp for linking */ 2460 mchunkptr fwd; /* misc temp for linking */ 2461 int islr; /* track whether merging with last_remainder */ 2462 2463 #ifdef CONFIG_SYS_MALLOC_F_LEN 2464 /* free() is a no-op - all the memory will be freed on relocation */ 2465 if (!(gd->flags & GD_FLG_RELOC)) 2466 return; 2467 #endif 2468 2469 if (mem == NULL) /* free(0) has no effect */ 2470 return; 2471 2472 p = mem2chunk(mem); 2473 hd = p->size; 2474 2475 #if HAVE_MMAP 2476 if (hd & IS_MMAPPED) /* release mmapped memory. */ 2477 { 2478 munmap_chunk(p); 2479 return; 2480 } 2481 #endif 2482 2483 check_inuse_chunk(p); 2484 2485 sz = hd & ~PREV_INUSE; 2486 next = chunk_at_offset(p, sz); 2487 nextsz = chunksize(next); 2488 2489 if (next == top) /* merge with top */ 2490 { 2491 sz += nextsz; 2492 2493 if (!(hd & PREV_INUSE)) /* consolidate backward */ 2494 { 2495 prevsz = p->prev_size; 2496 p = chunk_at_offset(p, -((long) prevsz)); 2497 sz += prevsz; 2498 unlink(p, bck, fwd); 2499 } 2500 2501 set_head(p, sz | PREV_INUSE); 2502 top = p; 2503 if ((unsigned long)(sz) >= (unsigned long)trim_threshold) 2504 malloc_trim(top_pad); 2505 return; 2506 } 2507 2508 set_head(next, nextsz); /* clear inuse bit */ 2509 2510 islr = 0; 2511 2512 if (!(hd & PREV_INUSE)) /* consolidate backward */ 2513 { 2514 prevsz = p->prev_size; 2515 p = chunk_at_offset(p, -((long) prevsz)); 2516 sz += prevsz; 2517 2518 if (p->fd == last_remainder) /* keep as last_remainder */ 2519 islr = 1; 2520 else 2521 unlink(p, bck, fwd); 2522 } 2523 2524 if (!(inuse_bit_at_offset(next, nextsz))) /* consolidate forward */ 2525 { 2526 sz += nextsz; 2527 2528 if (!islr && next->fd == last_remainder) /* re-insert last_remainder */ 2529 { 2530 islr = 1; 2531 link_last_remainder(p); 2532 } 2533 else 2534 unlink(next, bck, fwd); 2535 } 2536 2537 2538 set_head(p, sz | PREV_INUSE); 2539 set_foot(p, sz); 2540 if (!islr) 2541 frontlink(p, sz, idx, bck, fwd); 2542 } 2543 2544 2545 2546 2547 2548 /* 2549 2550 Realloc algorithm: 2551 2552 Chunks that were obtained via mmap cannot be extended or shrunk 2553 unless HAVE_MREMAP is defined, in which case mremap is used. 2554 Otherwise, if their reallocation is for additional space, they are 2555 copied. If for less, they are just left alone. 2556 2557 Otherwise, if the reallocation is for additional space, and the 2558 chunk can be extended, it is, else a malloc-copy-free sequence is 2559 taken. There are several different ways that a chunk could be 2560 extended. All are tried: 2561 2562 * Extending forward into following adjacent free chunk. 2563 * Shifting backwards, joining preceding adjacent space 2564 * Both shifting backwards and extending forward. 2565 * Extending into newly sbrked space 2566 2567 Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a 2568 size argument of zero (re)allocates a minimum-sized chunk. 2569 2570 If the reallocation is for less space, and the new request is for 2571 a `small' (<512 bytes) size, then the newly unused space is lopped 2572 off and freed. 2573 2574 The old unix realloc convention of allowing the last-free'd chunk 2575 to be used as an argument to realloc is no longer supported. 2576 I don't know of any programs still relying on this feature, 2577 and allowing it would also allow too many other incorrect 2578 usages of realloc to be sensible. 2579 2580 2581 */ 2582 2583 2584 #if __STD_C 2585 Void_t* rEALLOc(Void_t* oldmem, size_t bytes) 2586 #else 2587 Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes; 2588 #endif 2589 { 2590 INTERNAL_SIZE_T nb; /* padded request size */ 2591 2592 mchunkptr oldp; /* chunk corresponding to oldmem */ 2593 INTERNAL_SIZE_T oldsize; /* its size */ 2594 2595 mchunkptr newp; /* chunk to return */ 2596 INTERNAL_SIZE_T newsize; /* its size */ 2597 Void_t* newmem; /* corresponding user mem */ 2598 2599 mchunkptr next; /* next contiguous chunk after oldp */ 2600 INTERNAL_SIZE_T nextsize; /* its size */ 2601 2602 mchunkptr prev; /* previous contiguous chunk before oldp */ 2603 INTERNAL_SIZE_T prevsize; /* its size */ 2604 2605 mchunkptr remainder; /* holds split off extra space from newp */ 2606 INTERNAL_SIZE_T remainder_size; /* its size */ 2607 2608 mchunkptr bck; /* misc temp for linking */ 2609 mchunkptr fwd; /* misc temp for linking */ 2610 2611 #ifdef REALLOC_ZERO_BYTES_FREES 2612 if (bytes == 0) { fREe(oldmem); return 0; } 2613 #endif 2614 2615 if ((long)bytes < 0) return NULL; 2616 2617 /* realloc of null is supposed to be same as malloc */ 2618 if (oldmem == NULL) return mALLOc(bytes); 2619 2620 #ifdef CONFIG_SYS_MALLOC_F_LEN 2621 if (!(gd->flags & GD_FLG_RELOC)) { 2622 /* This is harder to support and should not be needed */ 2623 panic("pre-reloc realloc() is not supported"); 2624 } 2625 #endif 2626 2627 newp = oldp = mem2chunk(oldmem); 2628 newsize = oldsize = chunksize(oldp); 2629 2630 2631 nb = request2size(bytes); 2632 2633 #if HAVE_MMAP 2634 if (chunk_is_mmapped(oldp)) 2635 { 2636 #if HAVE_MREMAP 2637 newp = mremap_chunk(oldp, nb); 2638 if(newp) return chunk2mem(newp); 2639 #endif 2640 /* Note the extra SIZE_SZ overhead. */ 2641 if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */ 2642 /* Must alloc, copy, free. */ 2643 newmem = mALLOc(bytes); 2644 if (newmem == 0) return 0; /* propagate failure */ 2645 MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ); 2646 munmap_chunk(oldp); 2647 return newmem; 2648 } 2649 #endif 2650 2651 check_inuse_chunk(oldp); 2652 2653 if ((long)(oldsize) < (long)(nb)) 2654 { 2655 2656 /* Try expanding forward */ 2657 2658 next = chunk_at_offset(oldp, oldsize); 2659 if (next == top || !inuse(next)) 2660 { 2661 nextsize = chunksize(next); 2662 2663 /* Forward into top only if a remainder */ 2664 if (next == top) 2665 { 2666 if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE)) 2667 { 2668 newsize += nextsize; 2669 top = chunk_at_offset(oldp, nb); 2670 set_head(top, (newsize - nb) | PREV_INUSE); 2671 set_head_size(oldp, nb); 2672 return chunk2mem(oldp); 2673 } 2674 } 2675 2676 /* Forward into next chunk */ 2677 else if (((long)(nextsize + newsize) >= (long)(nb))) 2678 { 2679 unlink(next, bck, fwd); 2680 newsize += nextsize; 2681 goto split; 2682 } 2683 } 2684 else 2685 { 2686 next = NULL; 2687 nextsize = 0; 2688 } 2689 2690 /* Try shifting backwards. */ 2691 2692 if (!prev_inuse(oldp)) 2693 { 2694 prev = prev_chunk(oldp); 2695 prevsize = chunksize(prev); 2696 2697 /* try forward + backward first to save a later consolidation */ 2698 2699 if (next != NULL) 2700 { 2701 /* into top */ 2702 if (next == top) 2703 { 2704 if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE)) 2705 { 2706 unlink(prev, bck, fwd); 2707 newp = prev; 2708 newsize += prevsize + nextsize; 2709 newmem = chunk2mem(newp); 2710 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ); 2711 top = chunk_at_offset(newp, nb); 2712 set_head(top, (newsize - nb) | PREV_INUSE); 2713 set_head_size(newp, nb); 2714 return newmem; 2715 } 2716 } 2717 2718 /* into next chunk */ 2719 else if (((long)(nextsize + prevsize + newsize) >= (long)(nb))) 2720 { 2721 unlink(next, bck, fwd); 2722 unlink(prev, bck, fwd); 2723 newp = prev; 2724 newsize += nextsize + prevsize; 2725 newmem = chunk2mem(newp); 2726 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ); 2727 goto split; 2728 } 2729 } 2730 2731 /* backward only */ 2732 if (prev != NULL && (long)(prevsize + newsize) >= (long)nb) 2733 { 2734 unlink(prev, bck, fwd); 2735 newp = prev; 2736 newsize += prevsize; 2737 newmem = chunk2mem(newp); 2738 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ); 2739 goto split; 2740 } 2741 } 2742 2743 /* Must allocate */ 2744 2745 newmem = mALLOc (bytes); 2746 2747 if (newmem == NULL) /* propagate failure */ 2748 return NULL; 2749 2750 /* Avoid copy if newp is next chunk after oldp. */ 2751 /* (This can only happen when new chunk is sbrk'ed.) */ 2752 2753 if ( (newp = mem2chunk(newmem)) == next_chunk(oldp)) 2754 { 2755 newsize += chunksize(newp); 2756 newp = oldp; 2757 goto split; 2758 } 2759 2760 /* Otherwise copy, free, and exit */ 2761 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ); 2762 fREe(oldmem); 2763 return newmem; 2764 } 2765 2766 2767 split: /* split off extra room in old or expanded chunk */ 2768 2769 if (newsize - nb >= MINSIZE) /* split off remainder */ 2770 { 2771 remainder = chunk_at_offset(newp, nb); 2772 remainder_size = newsize - nb; 2773 set_head_size(newp, nb); 2774 set_head(remainder, remainder_size | PREV_INUSE); 2775 set_inuse_bit_at_offset(remainder, remainder_size); 2776 fREe(chunk2mem(remainder)); /* let free() deal with it */ 2777 } 2778 else 2779 { 2780 set_head_size(newp, newsize); 2781 set_inuse_bit_at_offset(newp, newsize); 2782 } 2783 2784 check_inuse_chunk(newp); 2785 return chunk2mem(newp); 2786 } 2787 2788 2789 2790 2791 /* 2792 2793 memalign algorithm: 2794 2795 memalign requests more than enough space from malloc, finds a spot 2796 within that chunk that meets the alignment request, and then 2797 possibly frees the leading and trailing space. 2798 2799 The alignment argument must be a power of two. This property is not 2800 checked by memalign, so misuse may result in random runtime errors. 2801 2802 8-byte alignment is guaranteed by normal malloc calls, so don't 2803 bother calling memalign with an argument of 8 or less. 2804 2805 Overreliance on memalign is a sure way to fragment space. 2806 2807 */ 2808 2809 2810 #if __STD_C 2811 Void_t* mEMALIGn(size_t alignment, size_t bytes) 2812 #else 2813 Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes; 2814 #endif 2815 { 2816 INTERNAL_SIZE_T nb; /* padded request size */ 2817 char* m; /* memory returned by malloc call */ 2818 mchunkptr p; /* corresponding chunk */ 2819 char* brk; /* alignment point within p */ 2820 mchunkptr newp; /* chunk to return */ 2821 INTERNAL_SIZE_T newsize; /* its size */ 2822 INTERNAL_SIZE_T leadsize; /* leading space befor alignment point */ 2823 mchunkptr remainder; /* spare room at end to split off */ 2824 long remainder_size; /* its size */ 2825 2826 if ((long)bytes < 0) return NULL; 2827 2828 /* If need less alignment than we give anyway, just relay to malloc */ 2829 2830 if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes); 2831 2832 /* Otherwise, ensure that it is at least a minimum chunk size */ 2833 2834 if (alignment < MINSIZE) alignment = MINSIZE; 2835 2836 /* Call malloc with worst case padding to hit alignment. */ 2837 2838 nb = request2size(bytes); 2839 m = (char*)(mALLOc(nb + alignment + MINSIZE)); 2840 2841 if (m == NULL) return NULL; /* propagate failure */ 2842 2843 p = mem2chunk(m); 2844 2845 if ((((unsigned long)(m)) % alignment) == 0) /* aligned */ 2846 { 2847 #if HAVE_MMAP 2848 if(chunk_is_mmapped(p)) 2849 return chunk2mem(p); /* nothing more to do */ 2850 #endif 2851 } 2852 else /* misaligned */ 2853 { 2854 /* 2855 Find an aligned spot inside chunk. 2856 Since we need to give back leading space in a chunk of at 2857 least MINSIZE, if the first calculation places us at 2858 a spot with less than MINSIZE leader, we can move to the 2859 next aligned spot -- we've allocated enough total room so that 2860 this is always possible. 2861 */ 2862 2863 brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -((signed) alignment)); 2864 if ((long)(brk - (char*)(p)) < MINSIZE) brk = brk + alignment; 2865 2866 newp = (mchunkptr)brk; 2867 leadsize = brk - (char*)(p); 2868 newsize = chunksize(p) - leadsize; 2869 2870 #if HAVE_MMAP 2871 if(chunk_is_mmapped(p)) 2872 { 2873 newp->prev_size = p->prev_size + leadsize; 2874 set_head(newp, newsize|IS_MMAPPED); 2875 return chunk2mem(newp); 2876 } 2877 #endif 2878 2879 /* give back leader, use the rest */ 2880 2881 set_head(newp, newsize | PREV_INUSE); 2882 set_inuse_bit_at_offset(newp, newsize); 2883 set_head_size(p, leadsize); 2884 fREe(chunk2mem(p)); 2885 p = newp; 2886 2887 assert (newsize >= nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0); 2888 } 2889 2890 /* Also give back spare room at the end */ 2891 2892 remainder_size = chunksize(p) - nb; 2893 2894 if (remainder_size >= (long)MINSIZE) 2895 { 2896 remainder = chunk_at_offset(p, nb); 2897 set_head(remainder, remainder_size | PREV_INUSE); 2898 set_head_size(p, nb); 2899 fREe(chunk2mem(remainder)); 2900 } 2901 2902 check_inuse_chunk(p); 2903 return chunk2mem(p); 2904 2905 } 2906 2907 2908 2909 2910 /* 2911 valloc just invokes memalign with alignment argument equal 2912 to the page size of the system (or as near to this as can 2913 be figured out from all the includes/defines above.) 2914 */ 2915 2916 #if __STD_C 2917 Void_t* vALLOc(size_t bytes) 2918 #else 2919 Void_t* vALLOc(bytes) size_t bytes; 2920 #endif 2921 { 2922 return mEMALIGn (malloc_getpagesize, bytes); 2923 } 2924 2925 /* 2926 pvalloc just invokes valloc for the nearest pagesize 2927 that will accommodate request 2928 */ 2929 2930 2931 #if __STD_C 2932 Void_t* pvALLOc(size_t bytes) 2933 #else 2934 Void_t* pvALLOc(bytes) size_t bytes; 2935 #endif 2936 { 2937 size_t pagesize = malloc_getpagesize; 2938 return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1)); 2939 } 2940 2941 /* 2942 2943 calloc calls malloc, then zeroes out the allocated chunk. 2944 2945 */ 2946 2947 #if __STD_C 2948 Void_t* cALLOc(size_t n, size_t elem_size) 2949 #else 2950 Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size; 2951 #endif 2952 { 2953 mchunkptr p; 2954 INTERNAL_SIZE_T csz; 2955 2956 INTERNAL_SIZE_T sz = n * elem_size; 2957 2958 2959 /* check if expand_top called, in which case don't need to clear */ 2960 #if MORECORE_CLEARS 2961 mchunkptr oldtop = top; 2962 INTERNAL_SIZE_T oldtopsize = chunksize(top); 2963 #endif 2964 Void_t* mem = mALLOc (sz); 2965 2966 if ((long)n < 0) return NULL; 2967 2968 if (mem == NULL) 2969 return NULL; 2970 else 2971 { 2972 #ifdef CONFIG_SYS_MALLOC_F_LEN 2973 if (!(gd->flags & GD_FLG_RELOC)) { 2974 MALLOC_ZERO(mem, sz); 2975 return mem; 2976 } 2977 #endif 2978 p = mem2chunk(mem); 2979 2980 /* Two optional cases in which clearing not necessary */ 2981 2982 2983 #if HAVE_MMAP 2984 if (chunk_is_mmapped(p)) return mem; 2985 #endif 2986 2987 csz = chunksize(p); 2988 2989 #if MORECORE_CLEARS 2990 if (p == oldtop && csz > oldtopsize) 2991 { 2992 /* clear only the bytes from non-freshly-sbrked memory */ 2993 csz = oldtopsize; 2994 } 2995 #endif 2996 2997 MALLOC_ZERO(mem, csz - SIZE_SZ); 2998 return mem; 2999 } 3000 } 3001 3002 /* 3003 3004 cfree just calls free. It is needed/defined on some systems 3005 that pair it with calloc, presumably for odd historical reasons. 3006 3007 */ 3008 3009 #if !defined(INTERNAL_LINUX_C_LIB) || !defined(__ELF__) 3010 #if __STD_C 3011 void cfree(Void_t *mem) 3012 #else 3013 void cfree(mem) Void_t *mem; 3014 #endif 3015 { 3016 fREe(mem); 3017 } 3018 #endif 3019 3020 3021 3022 /* 3023 3024 Malloc_trim gives memory back to the system (via negative 3025 arguments to sbrk) if there is unused memory at the `high' end of 3026 the malloc pool. You can call this after freeing large blocks of 3027 memory to potentially reduce the system-level memory requirements 3028 of a program. However, it cannot guarantee to reduce memory. Under 3029 some allocation patterns, some large free blocks of memory will be 3030 locked between two used chunks, so they cannot be given back to 3031 the system. 3032 3033 The `pad' argument to malloc_trim represents the amount of free 3034 trailing space to leave untrimmed. If this argument is zero, 3035 only the minimum amount of memory to maintain internal data 3036 structures will be left (one page or less). Non-zero arguments 3037 can be supplied to maintain enough trailing space to service 3038 future expected allocations without having to re-obtain memory 3039 from the system. 3040 3041 Malloc_trim returns 1 if it actually released any memory, else 0. 3042 3043 */ 3044 3045 #if __STD_C 3046 int malloc_trim(size_t pad) 3047 #else 3048 int malloc_trim(pad) size_t pad; 3049 #endif 3050 { 3051 long top_size; /* Amount of top-most memory */ 3052 long extra; /* Amount to release */ 3053 char* current_brk; /* address returned by pre-check sbrk call */ 3054 char* new_brk; /* address returned by negative sbrk call */ 3055 3056 unsigned long pagesz = malloc_getpagesize; 3057 3058 top_size = chunksize(top); 3059 extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz; 3060 3061 if (extra < (long)pagesz) /* Not enough memory to release */ 3062 return 0; 3063 3064 else 3065 { 3066 /* Test to make sure no one else called sbrk */ 3067 current_brk = (char*)(MORECORE (0)); 3068 if (current_brk != (char*)(top) + top_size) 3069 return 0; /* Apparently we don't own memory; must fail */ 3070 3071 else 3072 { 3073 new_brk = (char*)(MORECORE (-extra)); 3074 3075 if (new_brk == (char*)(MORECORE_FAILURE)) /* sbrk failed? */ 3076 { 3077 /* Try to figure out what we have */ 3078 current_brk = (char*)(MORECORE (0)); 3079 top_size = current_brk - (char*)top; 3080 if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */ 3081 { 3082 sbrked_mem = current_brk - sbrk_base; 3083 set_head(top, top_size | PREV_INUSE); 3084 } 3085 check_chunk(top); 3086 return 0; 3087 } 3088 3089 else 3090 { 3091 /* Success. Adjust top accordingly. */ 3092 set_head(top, (top_size - extra) | PREV_INUSE); 3093 sbrked_mem -= extra; 3094 check_chunk(top); 3095 return 1; 3096 } 3097 } 3098 } 3099 } 3100 3101 3102 3103 /* 3104 malloc_usable_size: 3105 3106 This routine tells you how many bytes you can actually use in an 3107 allocated chunk, which may be more than you requested (although 3108 often not). You can use this many bytes without worrying about 3109 overwriting other allocated objects. Not a particularly great 3110 programming practice, but still sometimes useful. 3111 3112 */ 3113 3114 #if __STD_C 3115 size_t malloc_usable_size(Void_t* mem) 3116 #else 3117 size_t malloc_usable_size(mem) Void_t* mem; 3118 #endif 3119 { 3120 mchunkptr p; 3121 if (mem == NULL) 3122 return 0; 3123 else 3124 { 3125 p = mem2chunk(mem); 3126 if(!chunk_is_mmapped(p)) 3127 { 3128 if (!inuse(p)) return 0; 3129 check_inuse_chunk(p); 3130 return chunksize(p) - SIZE_SZ; 3131 } 3132 return chunksize(p) - 2*SIZE_SZ; 3133 } 3134 } 3135 3136 3137 3138 3139 /* Utility to update current_mallinfo for malloc_stats and mallinfo() */ 3140 3141 #ifdef DEBUG 3142 static void malloc_update_mallinfo() 3143 { 3144 int i; 3145 mbinptr b; 3146 mchunkptr p; 3147 #ifdef DEBUG 3148 mchunkptr q; 3149 #endif 3150 3151 INTERNAL_SIZE_T avail = chunksize(top); 3152 int navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0; 3153 3154 for (i = 1; i < NAV; ++i) 3155 { 3156 b = bin_at(i); 3157 for (p = last(b); p != b; p = p->bk) 3158 { 3159 #ifdef DEBUG 3160 check_free_chunk(p); 3161 for (q = next_chunk(p); 3162 q < top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE; 3163 q = next_chunk(q)) 3164 check_inuse_chunk(q); 3165 #endif 3166 avail += chunksize(p); 3167 navail++; 3168 } 3169 } 3170 3171 current_mallinfo.ordblks = navail; 3172 current_mallinfo.uordblks = sbrked_mem - avail; 3173 current_mallinfo.fordblks = avail; 3174 current_mallinfo.hblks = n_mmaps; 3175 current_mallinfo.hblkhd = mmapped_mem; 3176 current_mallinfo.keepcost = chunksize(top); 3177 3178 } 3179 #endif /* DEBUG */ 3180 3181 3182 3183 /* 3184 3185 malloc_stats: 3186 3187 Prints on the amount of space obtain from the system (both 3188 via sbrk and mmap), the maximum amount (which may be more than 3189 current if malloc_trim and/or munmap got called), the maximum 3190 number of simultaneous mmap regions used, and the current number 3191 of bytes allocated via malloc (or realloc, etc) but not yet 3192 freed. (Note that this is the number of bytes allocated, not the 3193 number requested. It will be larger than the number requested 3194 because of alignment and bookkeeping overhead.) 3195 3196 */ 3197 3198 #ifdef DEBUG 3199 void malloc_stats() 3200 { 3201 malloc_update_mallinfo(); 3202 printf("max system bytes = %10u\n", 3203 (unsigned int)(max_total_mem)); 3204 printf("system bytes = %10u\n", 3205 (unsigned int)(sbrked_mem + mmapped_mem)); 3206 printf("in use bytes = %10u\n", 3207 (unsigned int)(current_mallinfo.uordblks + mmapped_mem)); 3208 #if HAVE_MMAP 3209 printf("max mmap regions = %10u\n", 3210 (unsigned int)max_n_mmaps); 3211 #endif 3212 } 3213 #endif /* DEBUG */ 3214 3215 /* 3216 mallinfo returns a copy of updated current mallinfo. 3217 */ 3218 3219 #ifdef DEBUG 3220 struct mallinfo mALLINFo() 3221 { 3222 malloc_update_mallinfo(); 3223 return current_mallinfo; 3224 } 3225 #endif /* DEBUG */ 3226 3227 3228 3229 3230 /* 3231 mallopt: 3232 3233 mallopt is the general SVID/XPG interface to tunable parameters. 3234 The format is to provide a (parameter-number, parameter-value) pair. 3235 mallopt then sets the corresponding parameter to the argument 3236 value if it can (i.e., so long as the value is meaningful), 3237 and returns 1 if successful else 0. 3238 3239 See descriptions of tunable parameters above. 3240 3241 */ 3242 3243 #if __STD_C 3244 int mALLOPt(int param_number, int value) 3245 #else 3246 int mALLOPt(param_number, value) int param_number; int value; 3247 #endif 3248 { 3249 switch(param_number) 3250 { 3251 case M_TRIM_THRESHOLD: 3252 trim_threshold = value; return 1; 3253 case M_TOP_PAD: 3254 top_pad = value; return 1; 3255 case M_MMAP_THRESHOLD: 3256 mmap_threshold = value; return 1; 3257 case M_MMAP_MAX: 3258 #if HAVE_MMAP 3259 n_mmaps_max = value; return 1; 3260 #else 3261 if (value != 0) return 0; else n_mmaps_max = value; return 1; 3262 #endif 3263 3264 default: 3265 return 0; 3266 } 3267 } 3268 3269 /* 3270 3271 History: 3272 3273 V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee) 3274 * return null for negative arguments 3275 * Added Several WIN32 cleanups from Martin C. Fong <mcfong@yahoo.com> 3276 * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h' 3277 (e.g. WIN32 platforms) 3278 * Cleanup up header file inclusion for WIN32 platforms 3279 * Cleanup code to avoid Microsoft Visual C++ compiler complaints 3280 * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing 3281 memory allocation routines 3282 * Set 'malloc_getpagesize' for WIN32 platforms (needs more work) 3283 * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to 3284 usage of 'assert' in non-WIN32 code 3285 * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to 3286 avoid infinite loop 3287 * Always call 'fREe()' rather than 'free()' 3288 3289 V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee) 3290 * Fixed ordering problem with boundary-stamping 3291 3292 V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee) 3293 * Added pvalloc, as recommended by H.J. Liu 3294 * Added 64bit pointer support mainly from Wolfram Gloger 3295 * Added anonymously donated WIN32 sbrk emulation 3296 * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen 3297 * malloc_extend_top: fix mask error that caused wastage after 3298 foreign sbrks 3299 * Add linux mremap support code from HJ Liu 3300 3301 V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee) 3302 * Integrated most documentation with the code. 3303 * Add support for mmap, with help from 3304 Wolfram Gloger (Gloger@lrz.uni-muenchen.de). 3305 * Use last_remainder in more cases. 3306 * Pack bins using idea from colin@nyx10.cs.du.edu 3307 * Use ordered bins instead of best-fit threshhold 3308 * Eliminate block-local decls to simplify tracing and debugging. 3309 * Support another case of realloc via move into top 3310 * Fix error occuring when initial sbrk_base not word-aligned. 3311 * Rely on page size for units instead of SBRK_UNIT to 3312 avoid surprises about sbrk alignment conventions. 3313 * Add mallinfo, mallopt. Thanks to Raymond Nijssen 3314 (raymond@es.ele.tue.nl) for the suggestion. 3315 * Add `pad' argument to malloc_trim and top_pad mallopt parameter. 3316 * More precautions for cases where other routines call sbrk, 3317 courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de). 3318 * Added macros etc., allowing use in linux libc from 3319 H.J. Lu (hjl@gnu.ai.mit.edu) 3320 * Inverted this history list 3321 3322 V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee) 3323 * Re-tuned and fixed to behave more nicely with V2.6.0 changes. 3324 * Removed all preallocation code since under current scheme 3325 the work required to undo bad preallocations exceeds 3326 the work saved in good cases for most test programs. 3327 * No longer use return list or unconsolidated bins since 3328 no scheme using them consistently outperforms those that don't 3329 given above changes. 3330 * Use best fit for very large chunks to prevent some worst-cases. 3331 * Added some support for debugging 3332 3333 V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee) 3334 * Removed footers when chunks are in use. Thanks to 3335 Paul Wilson (wilson@cs.texas.edu) for the suggestion. 3336 3337 V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee) 3338 * Added malloc_trim, with help from Wolfram Gloger 3339 (wmglo@Dent.MED.Uni-Muenchen.DE). 3340 3341 V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g) 3342 3343 V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g) 3344 * realloc: try to expand in both directions 3345 * malloc: swap order of clean-bin strategy; 3346 * realloc: only conditionally expand backwards 3347 * Try not to scavenge used bins 3348 * Use bin counts as a guide to preallocation 3349 * Occasionally bin return list chunks in first scan 3350 * Add a few optimizations from colin@nyx10.cs.du.edu 3351 3352 V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g) 3353 * faster bin computation & slightly different binning 3354 * merged all consolidations to one part of malloc proper 3355 (eliminating old malloc_find_space & malloc_clean_bin) 3356 * Scan 2 returns chunks (not just 1) 3357 * Propagate failure in realloc if malloc returns 0 3358 * Add stuff to allow compilation on non-ANSI compilers 3359 from kpv@research.att.com 3360 3361 V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu) 3362 * removed potential for odd address access in prev_chunk 3363 * removed dependency on getpagesize.h 3364 * misc cosmetics and a bit more internal documentation 3365 * anticosmetics: mangled names in macros to evade debugger strangeness 3366 * tested on sparc, hp-700, dec-mips, rs6000 3367 with gcc & native cc (hp, dec only) allowing 3368 Detlefs & Zorn comparison study (in SIGPLAN Notices.) 3369 3370 Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu) 3371 * Based loosely on libg++-1.2X malloc. (It retains some of the overall 3372 structure of old version, but most details differ.) 3373 3374 */ 3375