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