1/* SPDX-License-Identifier: GPL-2.0+ */ 2/* 3 This code is based on a version of malloc/free/realloc written by Doug Lea and 4 released to the public domain. Send questions/comments/complaints/performance 5 data to dl@cs.oswego.edu 6 7* VERSION 2.6.6 Sun Mar 5 19:10:03 2000 Doug Lea (dl at gee) 8 9 Note: There may be an updated version of this malloc obtainable at 10 http://g.oswego.edu/pub/misc/malloc.c 11 Check before installing! 12 13* Why use this malloc? 14 15 This is not the fastest, most space-conserving, most portable, or 16 most tunable malloc ever written. However it is among the fastest 17 while also being among the most space-conserving, portable and tunable. 18 Consistent balance across these factors results in a good general-purpose 19 allocator. For a high-level description, see 20 http://g.oswego.edu/dl/html/malloc.html 21 22* Synopsis of public routines 23 24 (Much fuller descriptions are contained in the program documentation below.) 25 26 malloc(size_t n); 27 Return a pointer to a newly allocated chunk of at least n bytes, or null 28 if no space is available. 29 free(Void_t* p); 30 Release the chunk of memory pointed to by p, or no effect if p is null. 31 realloc(Void_t* p, size_t n); 32 Return a pointer to a chunk of size n that contains the same data 33 as does chunk p up to the minimum of (n, p's size) bytes, or null 34 if no space is available. The returned pointer may or may not be 35 the same as p. If p is null, equivalent to malloc. Unless the 36 #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a 37 size argument of zero (re)allocates a minimum-sized chunk. 38 memalign(size_t alignment, size_t n); 39 Return a pointer to a newly allocated chunk of n bytes, aligned 40 in accord with the alignment argument, which must be a power of 41 two. 42 valloc(size_t n); 43 Equivalent to memalign(pagesize, n), where pagesize is the page 44 size of the system (or as near to this as can be figured out from 45 all the includes/defines below.) 46 pvalloc(size_t n); 47 Equivalent to valloc(minimum-page-that-holds(n)), that is, 48 round up n to nearest pagesize. 49 calloc(size_t unit, size_t quantity); 50 Returns a pointer to quantity * unit bytes, with all locations 51 set to zero. 52 cfree(Void_t* p); 53 Equivalent to free(p). 54 malloc_trim(size_t pad); 55 Release all but pad bytes of freed top-most memory back 56 to the system. Return 1 if successful, else 0. 57 malloc_usable_size(Void_t* p); 58 Report the number usable allocated bytes associated with allocated 59 chunk p. This may or may not report more bytes than were requested, 60 due to alignment and minimum size constraints. 61 malloc_stats(); 62 Prints brief summary statistics on stderr. 63 mallinfo() 64 Returns (by copy) a struct containing various summary statistics. 65 mallopt(int parameter_number, int parameter_value) 66 Changes one of the tunable parameters described below. Returns 67 1 if successful in changing the parameter, else 0. 68 69* Vital statistics: 70 71 Alignment: 8-byte 72 8 byte alignment is currently hardwired into the design. This 73 seems to suffice for all current machines and C compilers. 74 75 Assumed pointer representation: 4 or 8 bytes 76 Code for 8-byte pointers is untested by me but has worked 77 reliably by Wolfram Gloger, who contributed most of the 78 changes supporting this. 79 80 Assumed size_t representation: 4 or 8 bytes 81 Note that size_t is allowed to be 4 bytes even if pointers are 8. 82 83 Minimum overhead per allocated chunk: 4 or 8 bytes 84 Each malloced chunk has a hidden overhead of 4 bytes holding size 85 and status information. 86 87 Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead) 88 8-byte ptrs: 24/32 bytes (including, 4/8 overhead) 89 90 When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte 91 ptrs but 4 byte size) or 24 (for 8/8) additional bytes are 92 needed; 4 (8) for a trailing size field 93 and 8 (16) bytes for free list pointers. Thus, the minimum 94 allocatable size is 16/24/32 bytes. 95 96 Even a request for zero bytes (i.e., malloc(0)) returns a 97 pointer to something of the minimum allocatable size. 98 99 Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes 100 8-byte size_t: 2^63 - 16 bytes 101 102 It is assumed that (possibly signed) size_t bit values suffice to 103 represent chunk sizes. `Possibly signed' is due to the fact 104 that `size_t' may be defined on a system as either a signed or 105 an unsigned type. To be conservative, values that would appear 106 as negative numbers are avoided. 107 Requests for sizes with a negative sign bit when the request 108 size is treaded as a long will return null. 109 110 Maximum overhead wastage per allocated chunk: normally 15 bytes 111 112 Alignnment demands, plus the minimum allocatable size restriction 113 make the normal worst-case wastage 15 bytes (i.e., up to 15 114 more bytes will be allocated than were requested in malloc), with 115 two exceptions: 116 1. Because requests for zero bytes allocate non-zero space, 117 the worst case wastage for a request of zero bytes is 24 bytes. 118 2. For requests >= mmap_threshold that are serviced via 119 mmap(), the worst case wastage is 8 bytes plus the remainder 120 from a system page (the minimal mmap unit); typically 4096 bytes. 121 122* Limitations 123 124 Here are some features that are NOT currently supported 125 126 * No user-definable hooks for callbacks and the like. 127 * No automated mechanism for fully checking that all accesses 128 to malloced memory stay within their bounds. 129 * No support for compaction. 130 131* Synopsis of compile-time options: 132 133 People have reported using previous versions of this malloc on all 134 versions of Unix, sometimes by tweaking some of the defines 135 below. It has been tested most extensively on Solaris and 136 Linux. It is also reported to work on WIN32 platforms. 137 People have also reported adapting this malloc for use in 138 stand-alone embedded systems. 139 140 The implementation is in straight, hand-tuned ANSI C. Among other 141 consequences, it uses a lot of macros. Because of this, to be at 142 all usable, this code should be compiled using an optimizing compiler 143 (for example gcc -O2) that can simplify expressions and control 144 paths. 145 146 __STD_C (default: derived from C compiler defines) 147 Nonzero if using ANSI-standard C compiler, a C++ compiler, or 148 a C compiler sufficiently close to ANSI to get away with it. 149 DEBUG (default: NOT defined) 150 Define to enable debugging. Adds fairly extensive assertion-based 151 checking to help track down memory errors, but noticeably slows down 152 execution. 153 REALLOC_ZERO_BYTES_FREES (default: NOT defined) 154 Define this if you think that realloc(p, 0) should be equivalent 155 to free(p). Otherwise, since malloc returns a unique pointer for 156 malloc(0), so does realloc(p, 0). 157 HAVE_MEMCPY (default: defined) 158 Define if you are not otherwise using ANSI STD C, but still 159 have memcpy and memset in your C library and want to use them. 160 Otherwise, simple internal versions are supplied. 161 USE_MEMCPY (default: 1 if HAVE_MEMCPY is defined, 0 otherwise) 162 Define as 1 if you want the C library versions of memset and 163 memcpy called in realloc and calloc (otherwise macro versions are used). 164 At least on some platforms, the simple macro versions usually 165 outperform libc versions. 166 HAVE_MMAP (default: defined as 1) 167 Define to non-zero to optionally make malloc() use mmap() to 168 allocate very large blocks. 169 HAVE_MREMAP (default: defined as 0 unless Linux libc set) 170 Define to non-zero to optionally make realloc() use mremap() to 171 reallocate very large blocks. 172 malloc_getpagesize (default: derived from system #includes) 173 Either a constant or routine call returning the system page size. 174 HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined) 175 Optionally define if you are on a system with a /usr/include/malloc.h 176 that declares struct mallinfo. It is not at all necessary to 177 define this even if you do, but will ensure consistency. 178 INTERNAL_SIZE_T (default: size_t) 179 Define to a 32-bit type (probably `unsigned int') if you are on a 180 64-bit machine, yet do not want or need to allow malloc requests of 181 greater than 2^31 to be handled. This saves space, especially for 182 very small chunks. 183 INTERNAL_LINUX_C_LIB (default: NOT defined) 184 Defined only when compiled as part of Linux libc. 185 Also note that there is some odd internal name-mangling via defines 186 (for example, internally, `malloc' is named `mALLOc') needed 187 when compiling in this case. These look funny but don't otherwise 188 affect anything. 189 WIN32 (default: undefined) 190 Define this on MS win (95, nt) platforms to compile in sbrk emulation. 191 LACKS_UNISTD_H (default: undefined if not WIN32) 192 Define this if your system does not have a <unistd.h>. 193 LACKS_SYS_PARAM_H (default: undefined if not WIN32) 194 Define this if your system does not have a <sys/param.h>. 195 MORECORE (default: sbrk) 196 The name of the routine to call to obtain more memory from the system. 197 MORECORE_FAILURE (default: -1) 198 The value returned upon failure of MORECORE. 199 MORECORE_CLEARS (default 1) 200 true (1) if the routine mapped to MORECORE zeroes out memory (which 201 holds for sbrk). 202 DEFAULT_TRIM_THRESHOLD 203 DEFAULT_TOP_PAD 204 DEFAULT_MMAP_THRESHOLD 205 DEFAULT_MMAP_MAX 206 Default values of tunable parameters (described in detail below) 207 controlling interaction with host system routines (sbrk, mmap, etc). 208 These values may also be changed dynamically via mallopt(). The 209 preset defaults are those that give best performance for typical 210 programs/systems. 211 USE_DL_PREFIX (default: undefined) 212 Prefix all public routines with the string 'dl'. Useful to 213 quickly avoid procedure declaration conflicts and linker symbol 214 conflicts with existing memory allocation routines. 215 216 217*/ 218 219 220#ifndef __MALLOC_H__ 221#define __MALLOC_H__ 222 223/* Preliminaries */ 224 225#ifndef __STD_C 226#ifdef __STDC__ 227#define __STD_C 1 228#else 229#if __cplusplus 230#define __STD_C 1 231#else 232#define __STD_C 0 233#endif /*__cplusplus*/ 234#endif /*__STDC__*/ 235#endif /*__STD_C*/ 236 237#ifndef Void_t 238#if (__STD_C || defined(WIN32)) 239#define Void_t void 240#else 241#define Void_t char 242#endif 243#endif /*Void_t*/ 244 245#if __STD_C 246#include <linux/stddef.h> /* for size_t */ 247#else 248#include <sys/types.h> 249#endif /* __STD_C */ 250 251#ifdef __cplusplus 252extern "C" { 253#endif 254 255#if 0 /* not for U-Boot */ 256#include <stdio.h> /* needed for malloc_stats */ 257#endif 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/* U-Boot defines memset() and memcpy in /include/linux/string.h 366void* memset(void*, int, size_t); 367void* memcpy(void*, const void*, size_t); 368*/ 369#include <linux/string.h> 370#else 371#ifdef WIN32 372/* On Win32 platforms, 'memset()' and 'memcpy()' are already declared in */ 373/* 'windows.h' */ 374#else 375Void_t* memset(); 376Void_t* memcpy(); 377#endif 378#endif 379#endif 380 381#if USE_MEMCPY 382 383/* The following macros are only invoked with (2n+1)-multiples of 384 INTERNAL_SIZE_T units, with a positive integer n. This is exploited 385 for fast inline execution when n is small. */ 386 387#define MALLOC_ZERO(charp, nbytes) \ 388do { \ 389 INTERNAL_SIZE_T mzsz = (nbytes); \ 390 if(mzsz <= 9*sizeof(mzsz)) { \ 391 INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp); \ 392 if(mzsz >= 5*sizeof(mzsz)) { *mz++ = 0; \ 393 *mz++ = 0; \ 394 if(mzsz >= 7*sizeof(mzsz)) { *mz++ = 0; \ 395 *mz++ = 0; \ 396 if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0; \ 397 *mz++ = 0; }}} \ 398 *mz++ = 0; \ 399 *mz++ = 0; \ 400 *mz = 0; \ 401 } else memset((charp), 0, mzsz); \ 402} while(0) 403 404#define MALLOC_COPY(dest,src,nbytes) \ 405do { \ 406 INTERNAL_SIZE_T mcsz = (nbytes); \ 407 if(mcsz <= 9*sizeof(mcsz)) { \ 408 INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src); \ 409 INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest); \ 410 if(mcsz >= 5*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ 411 *mcdst++ = *mcsrc++; \ 412 if(mcsz >= 7*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ 413 *mcdst++ = *mcsrc++; \ 414 if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ 415 *mcdst++ = *mcsrc++; }}} \ 416 *mcdst++ = *mcsrc++; \ 417 *mcdst++ = *mcsrc++; \ 418 *mcdst = *mcsrc ; \ 419 } else memcpy(dest, src, mcsz); \ 420} while(0) 421 422#else /* !USE_MEMCPY */ 423 424/* Use Duff's device for good zeroing/copying performance. */ 425 426#define MALLOC_ZERO(charp, nbytes) \ 427do { \ 428 INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp); \ 429 long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ 430 if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ 431 switch (mctmp) { \ 432 case 0: for(;;) { *mzp++ = 0; \ 433 case 7: *mzp++ = 0; \ 434 case 6: *mzp++ = 0; \ 435 case 5: *mzp++ = 0; \ 436 case 4: *mzp++ = 0; \ 437 case 3: *mzp++ = 0; \ 438 case 2: *mzp++ = 0; \ 439 case 1: *mzp++ = 0; if(mcn <= 0) break; mcn--; } \ 440 } \ 441} while(0) 442 443#define MALLOC_COPY(dest,src,nbytes) \ 444do { \ 445 INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \ 446 INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \ 447 long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ 448 if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ 449 switch (mctmp) { \ 450 case 0: for(;;) { *mcdst++ = *mcsrc++; \ 451 case 7: *mcdst++ = *mcsrc++; \ 452 case 6: *mcdst++ = *mcsrc++; \ 453 case 5: *mcdst++ = *mcsrc++; \ 454 case 4: *mcdst++ = *mcsrc++; \ 455 case 3: *mcdst++ = *mcsrc++; \ 456 case 2: *mcdst++ = *mcsrc++; \ 457 case 1: *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; } \ 458 } \ 459} while(0) 460 461#endif 462 463 464/* 465 Define HAVE_MMAP to optionally make malloc() use mmap() to 466 allocate very large blocks. These will be returned to the 467 operating system immediately after a free(). 468*/ 469 470/*** 471#ifndef HAVE_MMAP 472#define HAVE_MMAP 1 473#endif 474***/ 475#undef HAVE_MMAP /* Not available for U-Boot */ 476 477/* 478 Define HAVE_MREMAP to make realloc() use mremap() to re-allocate 479 large blocks. This is currently only possible on Linux with 480 kernel versions newer than 1.3.77. 481*/ 482 483/*** 484#ifndef HAVE_MREMAP 485#ifdef INTERNAL_LINUX_C_LIB 486#define HAVE_MREMAP 1 487#else 488#define HAVE_MREMAP 0 489#endif 490#endif 491***/ 492#undef HAVE_MREMAP /* Not available for U-Boot */ 493 494#ifdef HAVE_MMAP 495 496#include <unistd.h> 497#include <fcntl.h> 498#include <sys/mman.h> 499 500#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) 501#define MAP_ANONYMOUS MAP_ANON 502#endif 503 504#endif /* HAVE_MMAP */ 505 506/* 507 Access to system page size. To the extent possible, this malloc 508 manages memory from the system in page-size units. 509 510 The following mechanics for getpagesize were adapted from 511 bsd/gnu getpagesize.h 512*/ 513 514#define LACKS_UNISTD_H /* Shortcut for U-Boot */ 515#define malloc_getpagesize 4096 516 517#ifndef LACKS_UNISTD_H 518# include <unistd.h> 519#endif 520 521#ifndef malloc_getpagesize 522# ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */ 523# ifndef _SC_PAGE_SIZE 524# define _SC_PAGE_SIZE _SC_PAGESIZE 525# endif 526# endif 527# ifdef _SC_PAGE_SIZE 528# define malloc_getpagesize sysconf(_SC_PAGE_SIZE) 529# else 530# if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE) 531 extern size_t getpagesize(); 532# define malloc_getpagesize getpagesize() 533# else 534# ifdef WIN32 535# define malloc_getpagesize (4096) /* TBD: Use 'GetSystemInfo' instead */ 536# else 537# ifndef LACKS_SYS_PARAM_H 538# include <sys/param.h> 539# endif 540# ifdef EXEC_PAGESIZE 541# define malloc_getpagesize EXEC_PAGESIZE 542# else 543# ifdef NBPG 544# ifndef CLSIZE 545# define malloc_getpagesize NBPG 546# else 547# define malloc_getpagesize (NBPG * CLSIZE) 548# endif 549# else 550# ifdef NBPC 551# define malloc_getpagesize NBPC 552# else 553# ifdef PAGESIZE 554# define malloc_getpagesize PAGESIZE 555# else 556# define malloc_getpagesize (4096) /* just guess */ 557# endif 558# endif 559# endif 560# endif 561# endif 562# endif 563# endif 564#endif 565 566 567/* 568 569 This version of malloc supports the standard SVID/XPG mallinfo 570 routine that returns a struct containing the same kind of 571 information you can get from malloc_stats. It should work on 572 any SVID/XPG compliant system that has a /usr/include/malloc.h 573 defining struct mallinfo. (If you'd like to install such a thing 574 yourself, cut out the preliminary declarations as described above 575 and below and save them in a malloc.h file. But there's no 576 compelling reason to bother to do this.) 577 578 The main declaration needed is the mallinfo struct that is returned 579 (by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a 580 bunch of fields, most of which are not even meaningful in this 581 version of malloc. Some of these fields are are instead filled by 582 mallinfo() with other numbers that might possibly be of interest. 583 584 HAVE_USR_INCLUDE_MALLOC_H should be set if you have a 585 /usr/include/malloc.h file that includes a declaration of struct 586 mallinfo. If so, it is included; else an SVID2/XPG2 compliant 587 version is declared below. These must be precisely the same for 588 mallinfo() to work. 589 590*/ 591 592/* #define HAVE_USR_INCLUDE_MALLOC_H */ 593 594#ifdef HAVE_USR_INCLUDE_MALLOC_H 595#include "/usr/include/malloc.h" 596#else 597 598/* SVID2/XPG mallinfo structure */ 599 600struct mallinfo { 601 int arena; /* total space allocated from system */ 602 int ordblks; /* number of non-inuse chunks */ 603 int smblks; /* unused -- always zero */ 604 int hblks; /* number of mmapped regions */ 605 int hblkhd; /* total space in mmapped regions */ 606 int usmblks; /* unused -- always zero */ 607 int fsmblks; /* unused -- always zero */ 608 int uordblks; /* total allocated space */ 609 int fordblks; /* total non-inuse space */ 610 int keepcost; /* top-most, releasable (via malloc_trim) space */ 611}; 612 613/* SVID2/XPG mallopt options */ 614 615#define M_MXFAST 1 /* UNUSED in this malloc */ 616#define M_NLBLKS 2 /* UNUSED in this malloc */ 617#define M_GRAIN 3 /* UNUSED in this malloc */ 618#define M_KEEP 4 /* UNUSED in this malloc */ 619 620#endif 621 622/* mallopt options that actually do something */ 623 624#define M_TRIM_THRESHOLD -1 625#define M_TOP_PAD -2 626#define M_MMAP_THRESHOLD -3 627#define M_MMAP_MAX -4 628 629 630#ifndef DEFAULT_TRIM_THRESHOLD 631#define DEFAULT_TRIM_THRESHOLD (128 * 1024) 632#endif 633 634/* 635 M_TRIM_THRESHOLD is the maximum amount of unused top-most memory 636 to keep before releasing via malloc_trim in free(). 637 638 Automatic trimming is mainly useful in long-lived programs. 639 Because trimming via sbrk can be slow on some systems, and can 640 sometimes be wasteful (in cases where programs immediately 641 afterward allocate more large chunks) the value should be high 642 enough so that your overall system performance would improve by 643 releasing. 644 645 The trim threshold and the mmap control parameters (see below) 646 can be traded off with one another. Trimming and mmapping are 647 two different ways of releasing unused memory back to the 648 system. Between these two, it is often possible to keep 649 system-level demands of a long-lived program down to a bare 650 minimum. For example, in one test suite of sessions measuring 651 the XF86 X server on Linux, using a trim threshold of 128K and a 652 mmap threshold of 192K led to near-minimal long term resource 653 consumption. 654 655 If you are using this malloc in a long-lived program, it should 656 pay to experiment with these values. As a rough guide, you 657 might set to a value close to the average size of a process 658 (program) running on your system. Releasing this much memory 659 would allow such a process to run in memory. Generally, it's 660 worth it to tune for trimming rather tham memory mapping when a 661 program undergoes phases where several large chunks are 662 allocated and released in ways that can reuse each other's 663 storage, perhaps mixed with phases where there are no such 664 chunks at all. And in well-behaved long-lived programs, 665 controlling release of large blocks via trimming versus mapping 666 is usually faster. 667 668 However, in most programs, these parameters serve mainly as 669 protection against the system-level effects of carrying around 670 massive amounts of unneeded memory. Since frequent calls to 671 sbrk, mmap, and munmap otherwise degrade performance, the default 672 parameters are set to relatively high values that serve only as 673 safeguards. 674 675 The default trim value is high enough to cause trimming only in 676 fairly extreme (by current memory consumption standards) cases. 677 It must be greater than page size to have any useful effect. To 678 disable trimming completely, you can set to (unsigned long)(-1); 679 680 681*/ 682 683 684#ifndef DEFAULT_TOP_PAD 685#define DEFAULT_TOP_PAD (0) 686#endif 687 688/* 689 M_TOP_PAD is the amount of extra `padding' space to allocate or 690 retain whenever sbrk is called. It is used in two ways internally: 691 692 * When sbrk is called to extend the top of the arena to satisfy 693 a new malloc request, this much padding is added to the sbrk 694 request. 695 696 * When malloc_trim is called automatically from free(), 697 it is used as the `pad' argument. 698 699 In both cases, the actual amount of padding is rounded 700 so that the end of the arena is always a system page boundary. 701 702 The main reason for using padding is to avoid calling sbrk so 703 often. Having even a small pad greatly reduces the likelihood 704 that nearly every malloc request during program start-up (or 705 after trimming) will invoke sbrk, which needlessly wastes 706 time. 707 708 Automatic rounding-up to page-size units is normally sufficient 709 to avoid measurable overhead, so the default is 0. However, in 710 systems where sbrk is relatively slow, it can pay to increase 711 this value, at the expense of carrying around more memory than 712 the program needs. 713 714*/ 715 716 717#ifndef DEFAULT_MMAP_THRESHOLD 718#define DEFAULT_MMAP_THRESHOLD (128 * 1024) 719#endif 720 721/* 722 723 M_MMAP_THRESHOLD is the request size threshold for using mmap() 724 to service a request. Requests of at least this size that cannot 725 be allocated using already-existing space will be serviced via mmap. 726 (If enough normal freed space already exists it is used instead.) 727 728 Using mmap segregates relatively large chunks of memory so that 729 they can be individually obtained and released from the host 730 system. A request serviced through mmap is never reused by any 731 other request (at least not directly; the system may just so 732 happen to remap successive requests to the same locations). 733 734 Segregating space in this way has the benefit that mmapped space 735 can ALWAYS be individually released back to the system, which 736 helps keep the system level memory demands of a long-lived 737 program low. Mapped memory can never become `locked' between 738 other chunks, as can happen with normally allocated chunks, which 739 menas that even trimming via malloc_trim would not release them. 740 741 However, it has the disadvantages that: 742 743 1. The space cannot be reclaimed, consolidated, and then 744 used to service later requests, as happens with normal chunks. 745 2. It can lead to more wastage because of mmap page alignment 746 requirements 747 3. It causes malloc performance to be more dependent on host 748 system memory management support routines which may vary in 749 implementation quality and may impose arbitrary 750 limitations. Generally, servicing a request via normal 751 malloc steps is faster than going through a system's mmap. 752 753 All together, these considerations should lead you to use mmap 754 only for relatively large requests. 755 756 757*/ 758 759 760#ifndef DEFAULT_MMAP_MAX 761#ifdef HAVE_MMAP 762#define DEFAULT_MMAP_MAX (64) 763#else 764#define DEFAULT_MMAP_MAX (0) 765#endif 766#endif 767 768/* 769 M_MMAP_MAX is the maximum number of requests to simultaneously 770 service using mmap. This parameter exists because: 771 772 1. Some systems have a limited number of internal tables for 773 use by mmap. 774 2. In most systems, overreliance on mmap can degrade overall 775 performance. 776 3. If a program allocates many large regions, it is probably 777 better off using normal sbrk-based allocation routines that 778 can reclaim and reallocate normal heap memory. Using a 779 small value allows transition into this mode after the 780 first few allocations. 781 782 Setting to 0 disables all use of mmap. If HAVE_MMAP is not set, 783 the default value is 0, and attempts to set it to non-zero values 784 in mallopt will fail. 785*/ 786 787 788/* 789 USE_DL_PREFIX will prefix all public routines with the string 'dl'. 790 Useful to quickly avoid procedure declaration conflicts and linker 791 symbol conflicts with existing memory allocation routines. 792 793*/ 794 795/* 796 * Rename the U-Boot alloc functions so that sandbox can still use the system 797 * ones 798 */ 799#ifdef CONFIG_SANDBOX 800#define USE_DL_PREFIX 801#endif 802 803/* 804 805 Special defines for linux libc 806 807 Except when compiled using these special defines for Linux libc 808 using weak aliases, this malloc is NOT designed to work in 809 multithreaded applications. No semaphores or other concurrency 810 control are provided to ensure that multiple malloc or free calls 811 don't run at the same time, which could be disasterous. A single 812 semaphore could be used across malloc, realloc, and free (which is 813 essentially the effect of the linux weak alias approach). It would 814 be hard to obtain finer granularity. 815 816*/ 817 818 819#ifdef INTERNAL_LINUX_C_LIB 820 821#if __STD_C 822 823Void_t * __default_morecore_init (ptrdiff_t); 824Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init; 825 826#else 827 828Void_t * __default_morecore_init (); 829Void_t *(*__morecore)() = __default_morecore_init; 830 831#endif 832 833#define MORECORE (*__morecore) 834#define MORECORE_FAILURE 0 835#define MORECORE_CLEARS 1 836 837#else /* INTERNAL_LINUX_C_LIB */ 838 839#if __STD_C 840extern Void_t* sbrk(ptrdiff_t); 841#else 842extern Void_t* sbrk(); 843#endif 844 845#ifndef MORECORE 846#define MORECORE sbrk 847#endif 848 849#ifndef MORECORE_FAILURE 850#define MORECORE_FAILURE -1 851#endif 852 853#ifndef MORECORE_CLEARS 854#define MORECORE_CLEARS 1 855#endif 856 857#endif /* INTERNAL_LINUX_C_LIB */ 858 859#if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__) 860 861#define cALLOc __libc_calloc 862#define fREe __libc_free 863#define mALLOc __libc_malloc 864#define mEMALIGn __libc_memalign 865#define rEALLOc __libc_realloc 866#define vALLOc __libc_valloc 867#define pvALLOc __libc_pvalloc 868#define mALLINFo __libc_mallinfo 869#define mALLOPt __libc_mallopt 870 871#pragma weak calloc = __libc_calloc 872#pragma weak free = __libc_free 873#pragma weak cfree = __libc_free 874#pragma weak malloc = __libc_malloc 875#pragma weak memalign = __libc_memalign 876#pragma weak realloc = __libc_realloc 877#pragma weak valloc = __libc_valloc 878#pragma weak pvalloc = __libc_pvalloc 879#pragma weak mallinfo = __libc_mallinfo 880#pragma weak mallopt = __libc_mallopt 881 882#else 883 884void malloc_simple_info(void); 885 886/** 887 * malloc_enable_testing() - Put malloc() into test mode 888 * 889 * This only works if UNIT_TESTING is enabled 890 * 891 * @max_allocs: return -ENOMEM after max_allocs calls to malloc() 892 */ 893void malloc_enable_testing(int max_allocs); 894 895/** malloc_disable_testing() - Put malloc() into normal mode */ 896void malloc_disable_testing(void); 897 898#if CONFIG_IS_ENABLED(SYS_MALLOC_SIMPLE) 899#define malloc malloc_simple 900#define realloc realloc_simple 901#define memalign memalign_simple 902#if IS_ENABLED(CONFIG_VALGRIND) 903#define free free_simple 904#else 905static inline void free(void *ptr) {} 906#endif 907void *calloc(size_t nmemb, size_t size); 908void *realloc_simple(void *ptr, size_t size); 909#else 910 911# ifdef USE_DL_PREFIX 912# define cALLOc dlcalloc 913# define fREe dlfree 914# define mALLOc dlmalloc 915# define mEMALIGn dlmemalign 916# define rEALLOc dlrealloc 917# define vALLOc dlvalloc 918# define pvALLOc dlpvalloc 919# define mALLINFo dlmallinfo 920# define mALLOPt dlmallopt 921 922/* Ensure that U-Boot actually uses these too */ 923#define calloc dlcalloc 924#define free(ptr) dlfree(ptr) 925#define malloc(x) dlmalloc(x) 926#define memalign dlmemalign 927#define realloc dlrealloc 928#define valloc dlvalloc 929#define pvalloc dlpvalloc 930#define mallinfo() dlmallinfo() 931#define mallopt dlmallopt 932#define malloc_trim dlmalloc_trim 933#define malloc_usable_size dlmalloc_usable_size 934#define malloc_stats dlmalloc_stats 935 936# else /* USE_DL_PREFIX */ 937# define cALLOc calloc 938# define fREe free 939# define mALLOc malloc 940# define mEMALIGn memalign 941# define rEALLOc realloc 942# define vALLOc valloc 943# define pvALLOc pvalloc 944# define mALLINFo mallinfo 945# define mALLOPt mallopt 946# endif /* USE_DL_PREFIX */ 947 948#endif 949 950/* Set up pre-relocation malloc() ready for use */ 951int initf_malloc(void); 952 953/* Public routines */ 954 955/* Simple versions which can be used when space is tight */ 956void *malloc_simple(size_t size); 957void *memalign_simple(size_t alignment, size_t bytes); 958 959#pragma GCC visibility push(hidden) 960# if __STD_C 961 962Void_t* mALLOc(size_t); 963void fREe(Void_t*); 964Void_t* rEALLOc(Void_t*, size_t); 965Void_t* mEMALIGn(size_t, size_t); 966Void_t* vALLOc(size_t); 967Void_t* pvALLOc(size_t); 968Void_t* cALLOc(size_t, size_t); 969void cfree(Void_t*); 970int malloc_trim(size_t); 971size_t malloc_usable_size(Void_t*); 972void malloc_stats(void); 973int mALLOPt(int, int); 974struct mallinfo mALLINFo(void); 975# else 976Void_t* mALLOc(); 977void fREe(); 978Void_t* rEALLOc(); 979Void_t* mEMALIGn(); 980Void_t* vALLOc(); 981Void_t* pvALLOc(); 982Void_t* cALLOc(); 983void cfree(); 984int malloc_trim(); 985size_t malloc_usable_size(); 986void malloc_stats(); 987int mALLOPt(); 988struct mallinfo mALLINFo(); 989# endif 990#endif 991#pragma GCC visibility pop 992 993/* 994 * Begin and End of memory area for malloc(), and current "brk" 995 */ 996extern ulong mem_malloc_start; 997extern ulong mem_malloc_end; 998extern ulong mem_malloc_brk; 999 1000void mem_malloc_init(ulong start, ulong size); 1001 1002#ifdef __cplusplus 1003}; /* end of extern "C" */ 1004#endif 1005 1006#endif /* __MALLOC_H__ */ 1007