1 /* Malloc implementation for multiple threads without lock contention.
2 Copyright (C) 1996-2002, 2003 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Wolfram Gloger <wg@malloc.de>
5 and Doug Lea <dl@cs.oswego.edu>, 2001.
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public License as
9 published by the Free Software Foundation; either version 2.1 of the
10 License, or (at your option) any later version.
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; see the file COPYING.LIB. If not,
19 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 This is a version (aka ptmalloc2) of malloc/free/realloc written by
24 Doug Lea and adapted to multiple threads/arenas by Wolfram Gloger.
26 * Version ptmalloc2-20011215
29 VERSION 2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee)
31 Note: There may be an updated version of this malloc obtainable at
32 http://www.malloc.de/malloc/ptmalloc2.tar.gz
33 Check before installing!
37 In order to compile this implementation, a Makefile is provided with
38 the ptmalloc2 distribution, which has pre-defined targets for some
39 popular systems (e.g. "make posix" for Posix threads). All that is
40 typically required with regard to compiler flags is the selection of
41 the thread package via defining one out of USE_PTHREADS, USE_THR or
42 USE_SPROC. Check the thread-m.h file for what effects this has.
43 Many/most systems will additionally require USE_TSD_DATA_HACK to be
44 defined, so this is the default for "make posix".
46 * Why use this malloc?
48 This is not the fastest, most space-conserving, most portable, or
49 most tunable malloc ever written. However it is among the fastest
50 while also being among the most space-conserving, portable and tunable.
51 Consistent balance across these factors results in a good general-purpose
52 allocator for malloc-intensive programs.
54 The main properties of the algorithms are:
55 * For large (>= 512 bytes) requests, it is a pure best-fit allocator,
56 with ties normally decided via FIFO (i.e. least recently used).
57 * For small (<= 64 bytes by default) requests, it is a caching
58 allocator, that maintains pools of quickly recycled chunks.
59 * In between, and for combinations of large and small requests, it does
60 the best it can trying to meet both goals at once.
61 * For very large requests (>= 128KB by default), it relies on system
62 memory mapping facilities, if supported.
64 For a longer but slightly out of date high-level description, see
65 http://gee.cs.oswego.edu/dl/html/malloc.html
67 You may already by default be using a C library containing a malloc
68 that is based on some version of this malloc (for example in
69 linux). You might still want to use the one in this file in order to
70 customize settings or to avoid overheads associated with library
73 * Contents, described in more detail in "description of public routines" below.
75 Standard (ANSI/SVID/...) functions:
77 calloc(size_t n_elements, size_t element_size);
79 realloc(Void_t* p, size_t n);
80 memalign(size_t alignment, size_t n);
83 mallopt(int parameter_number, int parameter_value)
86 independent_calloc(size_t n_elements, size_t size, Void_t* chunks[]);
87 independent_comalloc(size_t n_elements, size_t sizes[], Void_t* chunks[]);
90 malloc_trim(size_t pad);
91 malloc_usable_size(Void_t* p);
96 Supported pointer representation: 4 or 8 bytes
97 Supported size_t representation: 4 or 8 bytes
98 Note that size_t is allowed to be 4 bytes even if pointers are 8.
99 You can adjust this by defining INTERNAL_SIZE_T
101 Alignment: 2 * sizeof(size_t) (default)
102 (i.e., 8 byte alignment with 4byte size_t). This suffices for
103 nearly all current machines and C compilers. However, you can
104 define MALLOC_ALIGNMENT to be wider than this if necessary.
106 Minimum overhead per allocated chunk: 4 or 8 bytes
107 Each malloced chunk has a hidden word of overhead holding size
108 and status information.
110 Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead)
111 8-byte ptrs: 24/32 bytes (including, 4/8 overhead)
113 When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
114 ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
115 needed; 4 (8) for a trailing size field and 8 (16) bytes for
116 free list pointers. Thus, the minimum allocatable size is
119 Even a request for zero bytes (i.e., malloc(0)) returns a
120 pointer to something of the minimum allocatable size.
122 The maximum overhead wastage (i.e., number of extra bytes
123 allocated than were requested in malloc) is less than or equal
124 to the minimum size, except for requests >= mmap_threshold that
125 are serviced via mmap(), where the worst case wastage is 2 *
126 sizeof(size_t) bytes plus the remainder from a system page (the
127 minimal mmap unit); typically 4096 or 8192 bytes.
129 Maximum allocated size: 4-byte size_t: 2^32 minus about two pages
130 8-byte size_t: 2^64 minus about two pages
132 It is assumed that (possibly signed) size_t values suffice to
133 represent chunk sizes. `Possibly signed' is due to the fact
134 that `size_t' may be defined on a system as either a signed or
135 an unsigned type. The ISO C standard says that it must be
136 unsigned, but a few systems are known not to adhere to this.
137 Additionally, even when size_t is unsigned, sbrk (which is by
138 default used to obtain memory from system) accepts signed
139 arguments, and may not be able to handle size_t-wide arguments
140 with negative sign bit. Generally, values that would
141 appear as negative after accounting for overhead and alignment
142 are supported only via mmap(), which does not have this
145 Requests for sizes outside the allowed range will perform an optional
146 failure action and then return null. (Requests may also
147 also fail because a system is out of memory.)
149 Thread-safety: thread-safe unless NO_THREADS is defined
151 Compliance: I believe it is compliant with the 1997 Single Unix Specification
152 (See http://www.opennc.org). Also SVID/XPG, ANSI C, and probably
155 * Synopsis of compile-time options:
157 People have reported using previous versions of this malloc on all
158 versions of Unix, sometimes by tweaking some of the defines
159 below. It has been tested most extensively on Solaris and
160 Linux. It is also reported to work on WIN32 platforms.
161 People also report using it in stand-alone embedded systems.
163 The implementation is in straight, hand-tuned ANSI C. It is not
164 at all modular. (Sorry!) It uses a lot of macros. To be at all
165 usable, this code should be compiled using an optimizing compiler
166 (for example gcc -O3) that can simplify expressions and control
167 paths. (FAQ: some macros import variables as arguments rather than
168 declare locals because people reported that some debuggers
169 otherwise get confused.)
173 Compilation Environment options:
175 __STD_C derived from C compiler defines
178 USE_MEMCPY 1 if HAVE_MEMCPY is defined
179 HAVE_MMAP defined as 1
181 HAVE_MREMAP 0 unless linux defined
182 USE_ARENAS the same as HAVE_MMAP
183 malloc_getpagesize derived from system #includes, or 4096 if not
184 HAVE_USR_INCLUDE_MALLOC_H NOT defined
185 LACKS_UNISTD_H NOT defined unless WIN32
186 LACKS_SYS_PARAM_H NOT defined unless WIN32
187 LACKS_SYS_MMAN_H NOT defined unless WIN32
189 Changing default word sizes:
191 INTERNAL_SIZE_T size_t
192 MALLOC_ALIGNMENT 2 * sizeof(INTERNAL_SIZE_T)
194 Configuration and functionality options:
196 USE_DL_PREFIX NOT defined
197 USE_PUBLIC_MALLOC_WRAPPERS NOT defined
198 USE_MALLOC_LOCK NOT defined
199 MALLOC_DEBUG NOT defined
200 REALLOC_ZERO_BYTES_FREES 1
201 MALLOC_FAILURE_ACTION errno = ENOMEM, if __STD_C defined, else no-op
204 Options for customizing MORECORE:
208 MORECORE_CONTIGUOUS 1
209 MORECORE_CANNOT_TRIM NOT defined
211 MMAP_AS_MORECORE_SIZE (1024 * 1024)
213 Tuning options that are also dynamically changeable via mallopt:
216 DEFAULT_TRIM_THRESHOLD 128 * 1024
218 DEFAULT_MMAP_THRESHOLD 128 * 1024
219 DEFAULT_MMAP_MAX 65536
221 There are several other #defined constants and macros that you
222 probably don't want to touch unless you are extending or adapting malloc. */
225 __STD_C should be nonzero if using ANSI-standard C compiler, a C++
226 compiler, or a C compiler sufficiently close to ANSI to get away
231 #if defined(__STDC__) || defined(__cplusplus)
240 Void_t* is the pointer type that malloc should say it returns
244 #if (__STD_C || defined(WIN32))
252 #include <stddef.h> /* for size_t */
253 #include <stdlib.h> /* for getenv(), abort() */
255 #include <sys/types.h>
262 /* define LACKS_UNISTD_H if your system does not have a <unistd.h>. */
264 /* #define LACKS_UNISTD_H */
266 #ifndef LACKS_UNISTD_H
270 /* define LACKS_SYS_PARAM_H if your system does not have a <sys/param.h>. */
272 /* #define LACKS_SYS_PARAM_H */
275 #include <stdio.h> /* needed for malloc_stats */
276 #include <errno.h> /* needed for optional MALLOC_FAILURE_ACTION */
282 Because freed chunks may be overwritten with bookkeeping fields, this
283 malloc will often die when freed memory is overwritten by user
284 programs. This can be very effective (albeit in an annoying way)
285 in helping track down dangling pointers.
287 If you compile with -DMALLOC_DEBUG, a number of assertion checks are
288 enabled that will catch more memory errors. You probably won't be
289 able to make much sense of the actual assertion errors, but they
290 should help you locate incorrectly overwritten memory. The checking
291 is fairly extensive, and will slow down execution
292 noticeably. Calling malloc_stats or mallinfo with MALLOC_DEBUG set
293 will attempt to check every non-mmapped allocated and free chunk in
294 the course of computing the summmaries. (By nature, mmapped regions
295 cannot be checked very much automatically.)
297 Setting MALLOC_DEBUG may also be helpful if you are trying to modify
298 this code. The assertions in the check routines spell out in more
299 detail the assumptions and invariants underlying the algorithms.
301 Setting MALLOC_DEBUG does NOT provide an automated mechanism for
302 checking that all accesses to malloced memory stay within their
303 bounds. However, there are several add-ons and adaptations of this
304 or other mallocs available that do this.
311 #define assert(x) ((void)0)
316 INTERNAL_SIZE_T is the word-size used for internal bookkeeping
319 The default version is the same as size_t.
321 While not strictly necessary, it is best to define this as an
322 unsigned type, even if size_t is a signed type. This may avoid some
323 artificial size limitations on some systems.
325 On a 64-bit machine, you may be able to reduce malloc overhead by
326 defining INTERNAL_SIZE_T to be a 32 bit `unsigned int' at the
327 expense of not being able to handle more than 2^32 of malloced
328 space. If this limitation is acceptable, you are encouraged to set
329 this unless you are on a platform requiring 16byte alignments. In
330 this case the alignment requirements turn out to negate any
331 potential advantages of decreasing size_t word size.
333 Implementors: Beware of the possible combinations of:
334 - INTERNAL_SIZE_T might be signed or unsigned, might be 32 or 64 bits,
335 and might be the same width as int or as long
336 - size_t might have different width and signedness as INTERNAL_SIZE_T
337 - int and long might be 32 or 64 bits, and might be the same width
338 To deal with this, most comparisons and difference computations
339 among INTERNAL_SIZE_Ts should cast them to unsigned long, being
340 aware of the fact that casting an unsigned int to a wider long does
341 not sign-extend. (This also makes checking for negative numbers
342 awkward.) Some of these casts result in harmless compiler warnings
346 #ifndef INTERNAL_SIZE_T
347 #define INTERNAL_SIZE_T size_t
350 /* The corresponding word size */
351 #define SIZE_SZ (sizeof(INTERNAL_SIZE_T))
355 MALLOC_ALIGNMENT is the minimum alignment for malloc'ed chunks.
356 It must be a power of two at least 2 * SIZE_SZ, even on machines
357 for which smaller alignments would suffice. It may be defined as
358 larger than this though. Note however that code and data structures
359 are optimized for the case of 8-byte alignment.
363 #ifndef MALLOC_ALIGNMENT
364 #define MALLOC_ALIGNMENT (2 * SIZE_SZ)
367 /* The corresponding bit mask value */
368 #define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)
373 REALLOC_ZERO_BYTES_FREES should be set if a call to
374 realloc with zero bytes should be the same as a call to free.
375 This is required by the C standard. Otherwise, since this malloc
376 returns a unique pointer for malloc(0), so does realloc(p, 0).
379 #ifndef REALLOC_ZERO_BYTES_FREES
380 #define REALLOC_ZERO_BYTES_FREES 1
384 TRIM_FASTBINS controls whether free() of a very small chunk can
385 immediately lead to trimming. Setting to true (1) can reduce memory
386 footprint, but will almost always slow down programs that use a lot
389 Define this only if you are willing to give up some speed to more
390 aggressively reduce system-level memory footprint when releasing
391 memory in programs that use many small chunks. You can get
392 essentially the same effect by setting MXFAST to 0, but this can
393 lead to even greater slowdowns in programs using many small chunks.
394 TRIM_FASTBINS is an in-between compile-time option, that disables
395 only those chunks bordering topmost memory from being placed in
399 #ifndef TRIM_FASTBINS
400 #define TRIM_FASTBINS 0
405 USE_DL_PREFIX will prefix all public routines with the string 'dl'.
406 This is necessary when you only want to use this malloc in one part
407 of a program, using your regular system malloc elsewhere.
410 /* #define USE_DL_PREFIX */
414 Two-phase name translation.
415 All of the actual routines are given mangled names.
416 When wrappers are used, they become the public callable versions.
417 When DL_PREFIX is used, the callable names are prefixed.
421 #define public_cALLOc dlcalloc
422 #define public_fREe dlfree
423 #define public_cFREe dlcfree
424 #define public_mALLOc dlmalloc
425 #define public_mEMALIGn dlmemalign
426 #define public_rEALLOc dlrealloc
427 #define public_vALLOc dlvalloc
428 #define public_pVALLOc dlpvalloc
429 #define public_mALLINFo dlmallinfo
430 #define public_mALLOPt dlmallopt
431 #define public_mTRIm dlmalloc_trim
432 #define public_mSTATs dlmalloc_stats
433 #define public_mUSABLe dlmalloc_usable_size
434 #define public_iCALLOc dlindependent_calloc
435 #define public_iCOMALLOc dlindependent_comalloc
436 #define public_gET_STATe dlget_state
437 #define public_sET_STATe dlset_state
438 #else /* USE_DL_PREFIX */
441 /* Special defines for the GNU C library. */
442 #define public_cALLOc __libc_calloc
443 #define public_fREe __libc_free
444 #define public_cFREe __libc_cfree
445 #define public_mALLOc __libc_malloc
446 #define public_mEMALIGn __libc_memalign
447 #define public_rEALLOc __libc_realloc
448 #define public_vALLOc __libc_valloc
449 #define public_pVALLOc __libc_pvalloc
450 #define public_mALLINFo __libc_mallinfo
451 #define public_mALLOPt __libc_mallopt
452 #define public_mTRIm __malloc_trim
453 #define public_mSTATs __malloc_stats
454 #define public_mUSABLe __malloc_usable_size
455 #define public_iCALLOc __libc_independent_calloc
456 #define public_iCOMALLOc __libc_independent_comalloc
457 #define public_gET_STATe __malloc_get_state
458 #define public_sET_STATe __malloc_set_state
459 #define malloc_getpagesize __getpagesize()
462 #define munmap __munmap
463 #define mremap __mremap
464 #define mprotect __mprotect
465 #define MORECORE (*__morecore)
466 #define MORECORE_FAILURE 0
468 Void_t
* __default_morecore (ptrdiff_t);
469 Void_t
*(*__morecore
)(ptrdiff_t) = __default_morecore
;
472 #define public_cALLOc calloc
473 #define public_fREe free
474 #define public_cFREe cfree
475 #define public_mALLOc malloc
476 #define public_mEMALIGn memalign
477 #define public_rEALLOc realloc
478 #define public_vALLOc valloc
479 #define public_pVALLOc pvalloc
480 #define public_mALLINFo mallinfo
481 #define public_mALLOPt mallopt
482 #define public_mTRIm malloc_trim
483 #define public_mSTATs malloc_stats
484 #define public_mUSABLe malloc_usable_size
485 #define public_iCALLOc independent_calloc
486 #define public_iCOMALLOc independent_comalloc
487 #define public_gET_STATe malloc_get_state
488 #define public_sET_STATe malloc_set_state
490 #endif /* USE_DL_PREFIX */
493 #define __builtin_expect(expr, val) (expr)
495 #define fwrite(buf, size, count, fp) _IO_fwrite (buf, size, count, fp)
499 HAVE_MEMCPY should be defined if you are not otherwise using
500 ANSI STD C, but still have memcpy and memset in your C library
501 and want to use them in calloc and realloc. Otherwise simple
502 macro versions are defined below.
504 USE_MEMCPY should be defined as 1 if you actually want to
505 have memset and memcpy called. People report that the macro
506 versions are faster than libc versions on some systems.
508 Even if USE_MEMCPY is set to 1, loops to copy/clear small chunks
509 (of <= 36 bytes) are manually unrolled in realloc and calloc.
523 #if (__STD_C || defined(HAVE_MEMCPY))
529 /* On Win32 memset and memcpy are already declared in windows.h */
532 void* memset(void*, int, size_t);
533 void* memcpy(void*, const void*, size_t);
543 MALLOC_FAILURE_ACTION is the action to take before "return 0" when
544 malloc fails to be able to return memory, either because memory is
545 exhausted or because of illegal arguments.
547 By default, sets errno if running on STD_C platform, else does nothing.
550 #ifndef MALLOC_FAILURE_ACTION
552 #define MALLOC_FAILURE_ACTION \
556 #define MALLOC_FAILURE_ACTION
561 MORECORE-related declarations. By default, rely on sbrk
565 #ifdef LACKS_UNISTD_H
566 #if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
568 extern Void_t
* sbrk(ptrdiff_t);
570 extern Void_t
* sbrk();
576 MORECORE is the name of the routine to call to obtain more memory
577 from the system. See below for general guidance on writing
578 alternative MORECORE functions, as well as a version for WIN32 and a
579 sample version for pre-OSX macos.
583 #define MORECORE sbrk
587 MORECORE_FAILURE is the value returned upon failure of MORECORE
588 as well as mmap. Since it cannot be an otherwise valid memory address,
589 and must reflect values of standard sys calls, you probably ought not
593 #ifndef MORECORE_FAILURE
594 #define MORECORE_FAILURE (-1)
598 If MORECORE_CONTIGUOUS is true, take advantage of fact that
599 consecutive calls to MORECORE with positive arguments always return
600 contiguous increasing addresses. This is true of unix sbrk. Even
601 if not defined, when regions happen to be contiguous, malloc will
602 permit allocations spanning regions obtained from different
603 calls. But defining this when applicable enables some stronger
604 consistency checks and space efficiencies.
607 #ifndef MORECORE_CONTIGUOUS
608 #define MORECORE_CONTIGUOUS 1
612 Define MORECORE_CANNOT_TRIM if your version of MORECORE
613 cannot release space back to the system when given negative
614 arguments. This is generally necessary only if you are using
615 a hand-crafted MORECORE function that cannot handle negative arguments.
618 /* #define MORECORE_CANNOT_TRIM */
620 /* MORECORE_CLEARS (default 1)
621 The degree to which the routine mapped to MORECORE zeroes out
622 memory: never (0), only for newly allocated space (1) or always
623 (2). The distinction between (1) and (2) is necessary because on
624 some systems, if the application first decrements and then
625 increments the break value, the contents of the reallocated space
629 #ifndef MORECORE_CLEARS
630 #define MORECORE_CLEARS 1
635 Define HAVE_MMAP as true to optionally make malloc() use mmap() to
636 allocate very large blocks. These will be returned to the
637 operating system immediately after a free(). Also, if mmap
638 is available, it is used as a backup strategy in cases where
639 MORECORE fails to provide space from system.
641 This malloc is best tuned to work with mmap for large requests.
642 If you do not have mmap, operations involving very large chunks (1MB
643 or so) may be slower than you'd like.
650 Standard unix mmap using /dev/zero clears memory so calloc doesn't
655 #define MMAP_CLEARS 1
660 #define MMAP_CLEARS 0
666 MMAP_AS_MORECORE_SIZE is the minimum mmap size argument to use if
667 sbrk fails, and mmap is used as a backup (which is done only if
668 HAVE_MMAP). The value must be a multiple of page size. This
669 backup strategy generally applies only when systems have "holes" in
670 address space, so sbrk cannot perform contiguous expansion, but
671 there is still space available on system. On systems for which
672 this is known to be useful (i.e. most linux kernels), this occurs
673 only when programs allocate huge amounts of memory. Between this,
674 and the fact that mmap regions tend to be limited, the size should
675 be large, to avoid too many mmap calls and thus avoid running out
679 #ifndef MMAP_AS_MORECORE_SIZE
680 #define MMAP_AS_MORECORE_SIZE (1024 * 1024)
684 Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
685 large blocks. This is currently only possible on Linux with
686 kernel versions newer than 1.3.77.
691 #define HAVE_MREMAP 1
693 #define HAVE_MREMAP 0
696 #endif /* HAVE_MMAP */
698 /* Define USE_ARENAS to enable support for multiple `arenas'. These
699 are allocated using mmap(), are necessary for threads and
700 occasionally useful to overcome address space limitations affecting
704 #define USE_ARENAS HAVE_MMAP
709 The system page size. To the extent possible, this malloc manages
710 memory from the system in page-size units. Note that this value is
711 cached during initialization into a field of malloc_state. So even
712 if malloc_getpagesize is a function, it is only called once.
714 The following mechanics for getpagesize were adapted from bsd/gnu
715 getpagesize.h. If none of the system-probes here apply, a value of
716 4096 is used, which should be OK: If they don't apply, then using
717 the actual value probably doesn't impact performance.
721 #ifndef malloc_getpagesize
723 #ifndef LACKS_UNISTD_H
727 # ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */
728 # ifndef _SC_PAGE_SIZE
729 # define _SC_PAGE_SIZE _SC_PAGESIZE
733 # ifdef _SC_PAGE_SIZE
734 # define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
736 # if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
737 extern size_t getpagesize();
738 # define malloc_getpagesize getpagesize()
740 # ifdef WIN32 /* use supplied emulation of getpagesize */
741 # define malloc_getpagesize getpagesize()
743 # ifndef LACKS_SYS_PARAM_H
744 # include <sys/param.h>
746 # ifdef EXEC_PAGESIZE
747 # define malloc_getpagesize EXEC_PAGESIZE
751 # define malloc_getpagesize NBPG
753 # define malloc_getpagesize (NBPG * CLSIZE)
757 # define malloc_getpagesize NBPC
760 # define malloc_getpagesize PAGESIZE
761 # else /* just guess */
762 # define malloc_getpagesize (4096)
773 This version of malloc supports the standard SVID/XPG mallinfo
774 routine that returns a struct containing usage properties and
775 statistics. It should work on any SVID/XPG compliant system that has
776 a /usr/include/malloc.h defining struct mallinfo. (If you'd like to
777 install such a thing yourself, cut out the preliminary declarations
778 as described above and below and save them in a malloc.h file. But
779 there's no compelling reason to bother to do this.)
781 The main declaration needed is the mallinfo struct that is returned
782 (by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a
783 bunch of fields that are not even meaningful in this version of
784 malloc. These fields are are instead filled by mallinfo() with
785 other numbers that might be of interest.
787 HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
788 /usr/include/malloc.h file that includes a declaration of struct
789 mallinfo. If so, it is included; else an SVID2/XPG2 compliant
790 version is declared below. These must be precisely the same for
791 mallinfo() to work. The original SVID version of this struct,
792 defined on most systems with mallinfo, declares all fields as
793 ints. But some others define as unsigned long. If your system
794 defines the fields using a type of different width than listed here,
795 you must #include your system version and #define
796 HAVE_USR_INCLUDE_MALLOC_H.
799 /* #define HAVE_USR_INCLUDE_MALLOC_H */
801 #ifdef HAVE_USR_INCLUDE_MALLOC_H
802 #include "/usr/include/malloc.h"
806 /* ---------- description of public routines ------------ */
810 Returns a pointer to a newly allocated chunk of at least n bytes, or null
811 if no space is available. Additionally, on failure, errno is
812 set to ENOMEM on ANSI C systems.
814 If n is zero, malloc returns a minumum-sized chunk. (The minimum
815 size is 16 bytes on most 32bit systems, and 24 or 32 bytes on 64bit
816 systems.) On most systems, size_t is an unsigned type, so calls
817 with negative arguments are interpreted as requests for huge amounts
818 of space, which will often fail. The maximum supported value of n
819 differs across systems, but is in all cases less than the maximum
820 representable value of a size_t.
823 Void_t
* public_mALLOc(size_t);
825 Void_t
* public_mALLOc();
830 Releases the chunk of memory pointed to by p, that had been previously
831 allocated using malloc or a related routine such as realloc.
832 It has no effect if p is null. It can have arbitrary (i.e., bad!)
833 effects if p has already been freed.
835 Unless disabled (using mallopt), freeing very large spaces will
836 when possible, automatically trigger operations that give
837 back unused memory to the system, thus reducing program footprint.
840 void public_fREe(Void_t
*);
846 calloc(size_t n_elements, size_t element_size);
847 Returns a pointer to n_elements * element_size bytes, with all locations
851 Void_t
* public_cALLOc(size_t, size_t);
853 Void_t
* public_cALLOc();
857 realloc(Void_t* p, size_t n)
858 Returns a pointer to a chunk of size n that contains the same data
859 as does chunk p up to the minimum of (n, p's size) bytes, or null
860 if no space is available.
862 The returned pointer may or may not be the same as p. The algorithm
863 prefers extending p when possible, otherwise it employs the
864 equivalent of a malloc-copy-free sequence.
866 If p is null, realloc is equivalent to malloc.
868 If space is not available, realloc returns null, errno is set (if on
869 ANSI) and p is NOT freed.
871 if n is for fewer bytes than already held by p, the newly unused
872 space is lopped off and freed if possible. Unless the #define
873 REALLOC_ZERO_BYTES_FREES is set, realloc with a size argument of
874 zero (re)allocates a minimum-sized chunk.
876 Large chunks that were internally obtained via mmap will always
877 be reallocated using malloc-copy-free sequences unless
878 the system supports MREMAP (currently only linux).
880 The old unix realloc convention of allowing the last-free'd chunk
881 to be used as an argument to realloc is not supported.
884 Void_t
* public_rEALLOc(Void_t
*, size_t);
886 Void_t
* public_rEALLOc();
890 memalign(size_t alignment, size_t n);
891 Returns a pointer to a newly allocated chunk of n bytes, aligned
892 in accord with the alignment argument.
894 The alignment argument should be a power of two. If the argument is
895 not a power of two, the nearest greater power is used.
896 8-byte alignment is guaranteed by normal malloc calls, so don't
897 bother calling memalign with an argument of 8 or less.
899 Overreliance on memalign is a sure way to fragment space.
902 Void_t
* public_mEMALIGn(size_t, size_t);
904 Void_t
* public_mEMALIGn();
909 Equivalent to memalign(pagesize, n), where pagesize is the page
910 size of the system. If the pagesize is unknown, 4096 is used.
913 Void_t
* public_vALLOc(size_t);
915 Void_t
* public_vALLOc();
921 mallopt(int parameter_number, int parameter_value)
922 Sets tunable parameters The format is to provide a
923 (parameter-number, parameter-value) pair. mallopt then sets the
924 corresponding parameter to the argument value if it can (i.e., so
925 long as the value is meaningful), and returns 1 if successful else
926 0. SVID/XPG/ANSI defines four standard param numbers for mallopt,
927 normally defined in malloc.h. Only one of these (M_MXFAST) is used
928 in this malloc. The others (M_NLBLKS, M_GRAIN, M_KEEP) don't apply,
929 so setting them has no effect. But this malloc also supports four
930 other options in mallopt. See below for details. Briefly, supported
931 parameters are as follows (listed defaults are for "typical"
934 Symbol param # default allowed param values
935 M_MXFAST 1 64 0-80 (0 disables fastbins)
936 M_TRIM_THRESHOLD -1 128*1024 any (-1U disables trimming)
938 M_MMAP_THRESHOLD -3 128*1024 any (or 0 if no MMAP support)
939 M_MMAP_MAX -4 65536 any (0 disables use of mmap)
942 int public_mALLOPt(int, int);
944 int public_mALLOPt();
950 Returns (by copy) a struct containing various summary statistics:
952 arena: current total non-mmapped bytes allocated from system
953 ordblks: the number of free chunks
954 smblks: the number of fastbin blocks (i.e., small chunks that
955 have been freed but not use resused or consolidated)
956 hblks: current number of mmapped regions
957 hblkhd: total bytes held in mmapped regions
958 usmblks: the maximum total allocated space. This will be greater
959 than current total if trimming has occurred.
960 fsmblks: total bytes held in fastbin blocks
961 uordblks: current total allocated space (normal or mmapped)
962 fordblks: total free space
963 keepcost: the maximum number of bytes that could ideally be released
964 back to system via malloc_trim. ("ideally" means that
965 it ignores page restrictions etc.)
967 Because these fields are ints, but internal bookkeeping may
968 be kept as longs, the reported values may wrap around zero and
972 struct mallinfo
public_mALLINFo(void);
974 struct mallinfo
public_mALLINFo();
978 independent_calloc(size_t n_elements, size_t element_size, Void_t* chunks[]);
980 independent_calloc is similar to calloc, but instead of returning a
981 single cleared space, it returns an array of pointers to n_elements
982 independent elements that can hold contents of size elem_size, each
983 of which starts out cleared, and can be independently freed,
984 realloc'ed etc. The elements are guaranteed to be adjacently
985 allocated (this is not guaranteed to occur with multiple callocs or
986 mallocs), which may also improve cache locality in some
989 The "chunks" argument is optional (i.e., may be null, which is
990 probably the most typical usage). If it is null, the returned array
991 is itself dynamically allocated and should also be freed when it is
992 no longer needed. Otherwise, the chunks array must be of at least
993 n_elements in length. It is filled in with the pointers to the
996 In either case, independent_calloc returns this pointer array, or
997 null if the allocation failed. If n_elements is zero and "chunks"
998 is null, it returns a chunk representing an array with zero elements
999 (which should be freed if not wanted).
1001 Each element must be individually freed when it is no longer
1002 needed. If you'd like to instead be able to free all at once, you
1003 should instead use regular calloc and assign pointers into this
1004 space to represent elements. (In this case though, you cannot
1005 independently free elements.)
1007 independent_calloc simplifies and speeds up implementations of many
1008 kinds of pools. It may also be useful when constructing large data
1009 structures that initially have a fixed number of fixed-sized nodes,
1010 but the number is not known at compile time, and some of the nodes
1011 may later need to be freed. For example:
1013 struct Node { int item; struct Node* next; };
1015 struct Node* build_list() {
1017 int n = read_number_of_nodes_needed();
1018 if (n <= 0) return 0;
1019 pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
1020 if (pool == 0) die();
1021 // organize into a linked list...
1022 struct Node* first = pool[0];
1023 for (i = 0; i < n-1; ++i)
1024 pool[i]->next = pool[i+1];
1025 free(pool); // Can now free the array (or not, if it is needed later)
1030 Void_t
** public_iCALLOc(size_t, size_t, Void_t
**);
1032 Void_t
** public_iCALLOc();
1036 independent_comalloc(size_t n_elements, size_t sizes[], Void_t* chunks[]);
1038 independent_comalloc allocates, all at once, a set of n_elements
1039 chunks with sizes indicated in the "sizes" array. It returns
1040 an array of pointers to these elements, each of which can be
1041 independently freed, realloc'ed etc. The elements are guaranteed to
1042 be adjacently allocated (this is not guaranteed to occur with
1043 multiple callocs or mallocs), which may also improve cache locality
1044 in some applications.
1046 The "chunks" argument is optional (i.e., may be null). If it is null
1047 the returned array is itself dynamically allocated and should also
1048 be freed when it is no longer needed. Otherwise, the chunks array
1049 must be of at least n_elements in length. It is filled in with the
1050 pointers to the chunks.
1052 In either case, independent_comalloc returns this pointer array, or
1053 null if the allocation failed. If n_elements is zero and chunks is
1054 null, it returns a chunk representing an array with zero elements
1055 (which should be freed if not wanted).
1057 Each element must be individually freed when it is no longer
1058 needed. If you'd like to instead be able to free all at once, you
1059 should instead use a single regular malloc, and assign pointers at
1060 particular offsets in the aggregate space. (In this case though, you
1061 cannot independently free elements.)
1063 independent_comallac differs from independent_calloc in that each
1064 element may have a different size, and also that it does not
1065 automatically clear elements.
1067 independent_comalloc can be used to speed up allocation in cases
1068 where several structs or objects must always be allocated at the
1069 same time. For example:
1074 void send_message(char* msg) {
1075 int msglen = strlen(msg);
1076 size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
1078 if (independent_comalloc(3, sizes, chunks) == 0)
1080 struct Head* head = (struct Head*)(chunks[0]);
1081 char* body = (char*)(chunks[1]);
1082 struct Foot* foot = (struct Foot*)(chunks[2]);
1086 In general though, independent_comalloc is worth using only for
1087 larger values of n_elements. For small values, you probably won't
1088 detect enough difference from series of malloc calls to bother.
1090 Overuse of independent_comalloc can increase overall memory usage,
1091 since it cannot reuse existing noncontiguous small chunks that
1092 might be available for some of the elements.
1095 Void_t
** public_iCOMALLOc(size_t, size_t*, Void_t
**);
1097 Void_t
** public_iCOMALLOc();
1103 Equivalent to valloc(minimum-page-that-holds(n)), that is,
1104 round up n to nearest pagesize.
1107 Void_t
* public_pVALLOc(size_t);
1109 Void_t
* public_pVALLOc();
1114 Equivalent to free(p).
1116 cfree is needed/defined on some systems that pair it with calloc,
1117 for odd historical reasons (such as: cfree is used in example
1118 code in the first edition of K&R).
1121 void public_cFREe(Void_t
*);
1123 void public_cFREe();
1127 malloc_trim(size_t pad);
1129 If possible, gives memory back to the system (via negative
1130 arguments to sbrk) if there is unused memory at the `high' end of
1131 the malloc pool. You can call this after freeing large blocks of
1132 memory to potentially reduce the system-level memory requirements
1133 of a program. However, it cannot guarantee to reduce memory. Under
1134 some allocation patterns, some large free blocks of memory will be
1135 locked between two used chunks, so they cannot be given back to
1138 The `pad' argument to malloc_trim represents the amount of free
1139 trailing space to leave untrimmed. If this argument is zero,
1140 only the minimum amount of memory to maintain internal data
1141 structures will be left (one page or less). Non-zero arguments
1142 can be supplied to maintain enough trailing space to service
1143 future expected allocations without having to re-obtain memory
1146 Malloc_trim returns 1 if it actually released any memory, else 0.
1147 On systems that do not support "negative sbrks", it will always
1151 int public_mTRIm(size_t);
1157 malloc_usable_size(Void_t* p);
1159 Returns the number of bytes you can actually use in
1160 an allocated chunk, which may be more than you requested (although
1161 often not) due to alignment and minimum size constraints.
1162 You can use this many bytes without worrying about
1163 overwriting other allocated objects. This is not a particularly great
1164 programming practice. malloc_usable_size can be more useful in
1165 debugging and assertions, for example:
1168 assert(malloc_usable_size(p) >= 256);
1172 size_t public_mUSABLe(Void_t
*);
1174 size_t public_mUSABLe();
1179 Prints on stderr the amount of space obtained from the system (both
1180 via sbrk and mmap), the maximum amount (which may be more than
1181 current if malloc_trim and/or munmap got called), and the current
1182 number of bytes allocated via malloc (or realloc, etc) but not yet
1183 freed. Note that this is the number of bytes allocated, not the
1184 number requested. It will be larger than the number requested
1185 because of alignment and bookkeeping overhead. Because it includes
1186 alignment wastage as being in use, this figure may be greater than
1187 zero even when no user-level chunks are allocated.
1189 The reported current and maximum system memory can be inaccurate if
1190 a program makes other calls to system memory allocation functions
1191 (normally sbrk) outside of malloc.
1193 malloc_stats prints only the most commonly interesting statistics.
1194 More information can be obtained by calling mallinfo.
1198 void public_mSTATs(void);
1200 void public_mSTATs();
1204 malloc_get_state(void);
1206 Returns the state of all malloc variables in an opaque data
1210 Void_t
* public_gET_STATe(void);
1212 Void_t
* public_gET_STATe();
1216 malloc_set_state(Void_t* state);
1218 Restore the state of all malloc variables from data obtained with
1222 int public_sET_STATe(Void_t
*);
1224 int public_sET_STATe();
1229 posix_memalign(void **memptr, size_t alignment, size_t size);
1231 POSIX wrapper like memalign(), checking for validity of size.
1233 int __posix_memalign(void **, size_t, size_t);
1236 /* mallopt tuning options */
1239 M_MXFAST is the maximum request size used for "fastbins", special bins
1240 that hold returned chunks without consolidating their spaces. This
1241 enables future requests for chunks of the same size to be handled
1242 very quickly, but can increase fragmentation, and thus increase the
1243 overall memory footprint of a program.
1245 This malloc manages fastbins very conservatively yet still
1246 efficiently, so fragmentation is rarely a problem for values less
1247 than or equal to the default. The maximum supported value of MXFAST
1248 is 80. You wouldn't want it any higher than this anyway. Fastbins
1249 are designed especially for use with many small structs, objects or
1250 strings -- the default handles structs/objects/arrays with sizes up
1251 to 8 4byte fields, or small strings representing words, tokens,
1252 etc. Using fastbins for larger objects normally worsens
1253 fragmentation without improving speed.
1255 M_MXFAST is set in REQUEST size units. It is internally used in
1256 chunksize units, which adds padding and alignment. You can reduce
1257 M_MXFAST to 0 to disable all use of fastbins. This causes the malloc
1258 algorithm to be a closer approximation of fifo-best-fit in all cases,
1259 not just for larger requests, but will generally cause it to be
1264 /* M_MXFAST is a standard SVID/XPG tuning option, usually listed in malloc.h */
1269 #ifndef DEFAULT_MXFAST
1270 #define DEFAULT_MXFAST 64
1275 M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
1276 to keep before releasing via malloc_trim in free().
1278 Automatic trimming is mainly useful in long-lived programs.
1279 Because trimming via sbrk can be slow on some systems, and can
1280 sometimes be wasteful (in cases where programs immediately
1281 afterward allocate more large chunks) the value should be high
1282 enough so that your overall system performance would improve by
1283 releasing this much memory.
1285 The trim threshold and the mmap control parameters (see below)
1286 can be traded off with one another. Trimming and mmapping are
1287 two different ways of releasing unused memory back to the
1288 system. Between these two, it is often possible to keep
1289 system-level demands of a long-lived program down to a bare
1290 minimum. For example, in one test suite of sessions measuring
1291 the XF86 X server on Linux, using a trim threshold of 128K and a
1292 mmap threshold of 192K led to near-minimal long term resource
1295 If you are using this malloc in a long-lived program, it should
1296 pay to experiment with these values. As a rough guide, you
1297 might set to a value close to the average size of a process
1298 (program) running on your system. Releasing this much memory
1299 would allow such a process to run in memory. Generally, it's
1300 worth it to tune for trimming rather tham memory mapping when a
1301 program undergoes phases where several large chunks are
1302 allocated and released in ways that can reuse each other's
1303 storage, perhaps mixed with phases where there are no such
1304 chunks at all. And in well-behaved long-lived programs,
1305 controlling release of large blocks via trimming versus mapping
1308 However, in most programs, these parameters serve mainly as
1309 protection against the system-level effects of carrying around
1310 massive amounts of unneeded memory. Since frequent calls to
1311 sbrk, mmap, and munmap otherwise degrade performance, the default
1312 parameters are set to relatively high values that serve only as
1315 The trim value It must be greater than page size to have any useful
1316 effect. To disable trimming completely, you can set to
1319 Trim settings interact with fastbin (MXFAST) settings: Unless
1320 TRIM_FASTBINS is defined, automatic trimming never takes place upon
1321 freeing a chunk with size less than or equal to MXFAST. Trimming is
1322 instead delayed until subsequent freeing of larger chunks. However,
1323 you can still force an attempted trim by calling malloc_trim.
1325 Also, trimming is not generally possible in cases where
1326 the main arena is obtained via mmap.
1328 Note that the trick some people use of mallocing a huge space and
1329 then freeing it at program startup, in an attempt to reserve system
1330 memory, doesn't have the intended effect under automatic trimming,
1331 since that memory will immediately be returned to the system.
1334 #define M_TRIM_THRESHOLD -1
1336 #ifndef DEFAULT_TRIM_THRESHOLD
1337 #define DEFAULT_TRIM_THRESHOLD (128 * 1024)
1341 M_TOP_PAD is the amount of extra `padding' space to allocate or
1342 retain whenever sbrk is called. It is used in two ways internally:
1344 * When sbrk is called to extend the top of the arena to satisfy
1345 a new malloc request, this much padding is added to the sbrk
1348 * When malloc_trim is called automatically from free(),
1349 it is used as the `pad' argument.
1351 In both cases, the actual amount of padding is rounded
1352 so that the end of the arena is always a system page boundary.
1354 The main reason for using padding is to avoid calling sbrk so
1355 often. Having even a small pad greatly reduces the likelihood
1356 that nearly every malloc request during program start-up (or
1357 after trimming) will invoke sbrk, which needlessly wastes
1360 Automatic rounding-up to page-size units is normally sufficient
1361 to avoid measurable overhead, so the default is 0. However, in
1362 systems where sbrk is relatively slow, it can pay to increase
1363 this value, at the expense of carrying around more memory than
1367 #define M_TOP_PAD -2
1369 #ifndef DEFAULT_TOP_PAD
1370 #define DEFAULT_TOP_PAD (0)
1374 M_MMAP_THRESHOLD is the request size threshold for using mmap()
1375 to service a request. Requests of at least this size that cannot
1376 be allocated using already-existing space will be serviced via mmap.
1377 (If enough normal freed space already exists it is used instead.)
1379 Using mmap segregates relatively large chunks of memory so that
1380 they can be individually obtained and released from the host
1381 system. A request serviced through mmap is never reused by any
1382 other request (at least not directly; the system may just so
1383 happen to remap successive requests to the same locations).
1385 Segregating space in this way has the benefits that:
1387 1. Mmapped space can ALWAYS be individually released back
1388 to the system, which helps keep the system level memory
1389 demands of a long-lived program low.
1390 2. Mapped memory can never become `locked' between
1391 other chunks, as can happen with normally allocated chunks, which
1392 means that even trimming via malloc_trim would not release them.
1393 3. On some systems with "holes" in address spaces, mmap can obtain
1394 memory that sbrk cannot.
1396 However, it has the disadvantages that:
1398 1. The space cannot be reclaimed, consolidated, and then
1399 used to service later requests, as happens with normal chunks.
1400 2. It can lead to more wastage because of mmap page alignment
1402 3. It causes malloc performance to be more dependent on host
1403 system memory management support routines which may vary in
1404 implementation quality and may impose arbitrary
1405 limitations. Generally, servicing a request via normal
1406 malloc steps is faster than going through a system's mmap.
1408 The advantages of mmap nearly always outweigh disadvantages for
1409 "large" chunks, but the value of "large" varies across systems. The
1410 default is an empirically derived value that works well in most
1414 #define M_MMAP_THRESHOLD -3
1416 #ifndef DEFAULT_MMAP_THRESHOLD
1417 #define DEFAULT_MMAP_THRESHOLD (128 * 1024)
1421 M_MMAP_MAX is the maximum number of requests to simultaneously
1422 service using mmap. This parameter exists because
1423 some systems have a limited number of internal tables for
1424 use by mmap, and using more than a few of them may degrade
1427 The default is set to a value that serves only as a safeguard.
1428 Setting to 0 disables use of mmap for servicing large requests. If
1429 HAVE_MMAP is not set, the default value is 0, and attempts to set it
1430 to non-zero values in mallopt will fail.
1433 #define M_MMAP_MAX -4
1435 #ifndef DEFAULT_MMAP_MAX
1437 #define DEFAULT_MMAP_MAX (65536)
1439 #define DEFAULT_MMAP_MAX (0)
1444 }; /* end of extern "C" */
1448 #include "thread-m.h"
1451 #define BOUNDED_N(ptr, sz) (ptr)
1453 #ifndef RETURN_ADDRESS
1454 #define RETURN_ADDRESS(X_) (NULL)
1457 /* On some platforms we can compile internal, not exported functions better.
1458 Let the environment provide a macro and define it to be empty if it
1459 is not available. */
1460 #ifndef internal_function
1461 # define internal_function
1464 /* Forward declarations. */
1465 struct malloc_chunk
;
1466 typedef struct malloc_chunk
* mchunkptr
;
1468 /* Internal routines. */
1472 Void_t
* _int_malloc(mstate
, size_t);
1473 void _int_free(mstate
, Void_t
*);
1474 Void_t
* _int_realloc(mstate
, Void_t
*, size_t);
1475 Void_t
* _int_memalign(mstate
, size_t, size_t);
1476 Void_t
* _int_valloc(mstate
, size_t);
1477 static Void_t
* _int_pvalloc(mstate
, size_t);
1478 /*static Void_t* cALLOc(size_t, size_t);*/
1479 static Void_t
** _int_icalloc(mstate
, size_t, size_t, Void_t
**);
1480 static Void_t
** _int_icomalloc(mstate
, size_t, size_t*, Void_t
**);
1481 static int mTRIm(size_t);
1482 static size_t mUSABLe(Void_t
*);
1483 static void mSTATs(void);
1484 static int mALLOPt(int, int);
1485 static struct mallinfo
mALLINFo(mstate
);
1487 static Void_t
* internal_function
mem2mem_check(Void_t
*p
, size_t sz
);
1488 static int internal_function
top_check(void);
1489 static void internal_function
munmap_chunk(mchunkptr p
);
1491 static mchunkptr internal_function
mremap_chunk(mchunkptr p
, size_t new_size
);
1494 static Void_t
* malloc_check(size_t sz
, const Void_t
*caller
);
1495 static void free_check(Void_t
* mem
, const Void_t
*caller
);
1496 static Void_t
* realloc_check(Void_t
* oldmem
, size_t bytes
,
1497 const Void_t
*caller
);
1498 static Void_t
* memalign_check(size_t alignment
, size_t bytes
,
1499 const Void_t
*caller
);
1502 # if USE___THREAD || (defined USE_TLS && !defined SHARED)
1503 /* These routines are never needed in this configuration. */
1510 static Void_t
* malloc_starter(size_t sz
, const Void_t
*caller
);
1511 static Void_t
* memalign_starter(size_t aln
, size_t sz
, const Void_t
*caller
);
1512 static void free_starter(Void_t
* mem
, const Void_t
*caller
);
1514 static Void_t
* malloc_atfork(size_t sz
, const Void_t
*caller
);
1515 static void free_atfork(Void_t
* mem
, const Void_t
*caller
);
1520 Void_t
* _int_malloc();
1522 Void_t
* _int_realloc();
1523 Void_t
* _int_memalign();
1524 Void_t
* _int_valloc();
1525 Void_t
* _int_pvalloc();
1526 /*static Void_t* cALLOc();*/
1527 static Void_t
** _int_icalloc();
1528 static Void_t
** _int_icomalloc();
1530 static size_t mUSABLe();
1531 static void mSTATs();
1532 static int mALLOPt();
1533 static struct mallinfo
mALLINFo();
1540 /* ------------- Optional versions of memcopy ---------------- */
1546 Note: memcpy is ONLY invoked with non-overlapping regions,
1547 so the (usually slower) memmove is not needed.
1550 #define MALLOC_COPY(dest, src, nbytes) memcpy(dest, src, nbytes)
1551 #define MALLOC_ZERO(dest, nbytes) memset(dest, 0, nbytes)
1553 #else /* !USE_MEMCPY */
1555 /* Use Duff's device for good zeroing/copying performance. */
1557 #define MALLOC_ZERO(charp, nbytes) \
1559 INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp); \
1560 unsigned long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T); \
1562 if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \
1564 case 0: for(;;) { *mzp++ = 0; \
1565 case 7: *mzp++ = 0; \
1566 case 6: *mzp++ = 0; \
1567 case 5: *mzp++ = 0; \
1568 case 4: *mzp++ = 0; \
1569 case 3: *mzp++ = 0; \
1570 case 2: *mzp++ = 0; \
1571 case 1: *mzp++ = 0; if(mcn <= 0) break; mcn--; } \
1575 #define MALLOC_COPY(dest,src,nbytes) \
1577 INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \
1578 INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \
1579 unsigned long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T); \
1581 if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \
1583 case 0: for(;;) { *mcdst++ = *mcsrc++; \
1584 case 7: *mcdst++ = *mcsrc++; \
1585 case 6: *mcdst++ = *mcsrc++; \
1586 case 5: *mcdst++ = *mcsrc++; \
1587 case 4: *mcdst++ = *mcsrc++; \
1588 case 3: *mcdst++ = *mcsrc++; \
1589 case 2: *mcdst++ = *mcsrc++; \
1590 case 1: *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; } \
1596 /* ------------------ MMAP support ------------------ */
1602 #ifndef LACKS_SYS_MMAN_H
1603 #include <sys/mman.h>
1606 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
1607 # define MAP_ANONYMOUS MAP_ANON
1609 #if !defined(MAP_FAILED)
1610 # define MAP_FAILED ((char*)-1)
1613 #ifndef MAP_NORESERVE
1614 # ifdef MAP_AUTORESRV
1615 # define MAP_NORESERVE MAP_AUTORESRV
1617 # define MAP_NORESERVE 0
1622 Nearly all versions of mmap support MAP_ANONYMOUS,
1623 so the following is unlikely to be needed, but is
1624 supplied just in case.
1627 #ifndef MAP_ANONYMOUS
1629 static int dev_zero_fd
= -1; /* Cached file descriptor for /dev/zero. */
1631 #define MMAP(addr, size, prot, flags) ((dev_zero_fd < 0) ? \
1632 (dev_zero_fd = open("/dev/zero", O_RDWR), \
1633 mmap((addr), (size), (prot), (flags), dev_zero_fd, 0)) : \
1634 mmap((addr), (size), (prot), (flags), dev_zero_fd, 0))
1638 #define MMAP(addr, size, prot, flags) \
1639 (mmap((addr), (size), (prot), (flags)|MAP_ANONYMOUS, -1, 0))
1644 #endif /* HAVE_MMAP */
1648 ----------------------- Chunk representations -----------------------
1653 This struct declaration is misleading (but accurate and necessary).
1654 It declares a "view" into memory allowing access to necessary
1655 fields at known offsets from a given base. See explanation below.
1658 struct malloc_chunk
{
1660 INTERNAL_SIZE_T prev_size
; /* Size of previous chunk (if free). */
1661 INTERNAL_SIZE_T size
; /* Size in bytes, including overhead. */
1663 struct malloc_chunk
* fd
; /* double links -- used only if free. */
1664 struct malloc_chunk
* bk
;
1669 malloc_chunk details:
1671 (The following includes lightly edited explanations by Colin Plumb.)
1673 Chunks of memory are maintained using a `boundary tag' method as
1674 described in e.g., Knuth or Standish. (See the paper by Paul
1675 Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
1676 survey of such techniques.) Sizes of free chunks are stored both
1677 in the front of each chunk and at the end. This makes
1678 consolidating fragmented chunks into bigger chunks very fast. The
1679 size fields also hold bits representing whether chunks are free or
1682 An allocated chunk looks like this:
1685 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1686 | Size of previous chunk, if allocated | |
1687 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1688 | Size of chunk, in bytes |P|
1689 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1690 | User data starts here... .
1692 . (malloc_usable_space() bytes) .
1694 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1696 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1699 Where "chunk" is the front of the chunk for the purpose of most of
1700 the malloc code, but "mem" is the pointer that is returned to the
1701 user. "Nextchunk" is the beginning of the next contiguous chunk.
1703 Chunks always begin on even word boundries, so the mem portion
1704 (which is returned to the user) is also on an even word boundary, and
1705 thus at least double-word aligned.
1707 Free chunks are stored in circular doubly-linked lists, and look like this:
1709 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1710 | Size of previous chunk |
1711 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1712 `head:' | Size of chunk, in bytes |P|
1713 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1714 | Forward pointer to next chunk in list |
1715 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1716 | Back pointer to previous chunk in list |
1717 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1718 | Unused space (may be 0 bytes long) .
1721 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1722 `foot:' | Size of chunk, in bytes |
1723 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1725 The P (PREV_INUSE) bit, stored in the unused low-order bit of the
1726 chunk size (which is always a multiple of two words), is an in-use
1727 bit for the *previous* chunk. If that bit is *clear*, then the
1728 word before the current chunk size contains the previous chunk
1729 size, and can be used to find the front of the previous chunk.
1730 The very first chunk allocated always has this bit set,
1731 preventing access to non-existent (or non-owned) memory. If
1732 prev_inuse is set for any given chunk, then you CANNOT determine
1733 the size of the previous chunk, and might even get a memory
1734 addressing fault when trying to do so.
1736 Note that the `foot' of the current chunk is actually represented
1737 as the prev_size of the NEXT chunk. This makes it easier to
1738 deal with alignments etc but can be very confusing when trying
1739 to extend or adapt this code.
1741 The two exceptions to all this are
1743 1. The special chunk `top' doesn't bother using the
1744 trailing size field since there is no next contiguous chunk
1745 that would have to index off it. After initialization, `top'
1746 is forced to always exist. If it would become less than
1747 MINSIZE bytes long, it is replenished.
1749 2. Chunks allocated via mmap, which have the second-lowest-order
1750 bit (IS_MMAPPED) set in their size fields. Because they are
1751 allocated one-by-one, each must contain its own trailing size field.
1756 ---------- Size and alignment checks and conversions ----------
1759 /* conversion from malloc headers to user pointers, and back */
1761 #define chunk2mem(p) ((Void_t*)((char*)(p) + 2*SIZE_SZ))
1762 #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))
1764 /* The smallest possible chunk */
1765 #define MIN_CHUNK_SIZE (sizeof(struct malloc_chunk))
1767 /* The smallest size we can malloc is an aligned minimal chunk */
1770 (unsigned long)(((MIN_CHUNK_SIZE+MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK))
1772 /* Check if m has acceptable alignment */
1774 #define aligned_OK(m) (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)
1778 Check if a request is so large that it would wrap around zero when
1779 padded and aligned. To simplify some other code, the bound is made
1780 low enough so that adding MINSIZE will also not wrap around zero.
1783 #define REQUEST_OUT_OF_RANGE(req) \
1784 ((unsigned long)(req) >= \
1785 (unsigned long)(INTERNAL_SIZE_T)(-2 * MINSIZE))
1787 /* pad request bytes into a usable size -- internal version */
1789 #define request2size(req) \
1790 (((req) + SIZE_SZ + MALLOC_ALIGN_MASK < MINSIZE) ? \
1792 ((req) + SIZE_SZ + MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK)
1794 /* Same, except also perform argument check */
1796 #define checked_request2size(req, sz) \
1797 if (REQUEST_OUT_OF_RANGE(req)) { \
1798 MALLOC_FAILURE_ACTION; \
1801 (sz) = request2size(req);
1804 --------------- Physical chunk operations ---------------
1808 /* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */
1809 #define PREV_INUSE 0x1
1811 /* extract inuse bit of previous chunk */
1812 #define prev_inuse(p) ((p)->size & PREV_INUSE)
1815 /* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */
1816 #define IS_MMAPPED 0x2
1818 /* check for mmap()'ed chunk */
1819 #define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)
1822 /* size field is or'ed with NON_MAIN_ARENA if the chunk was obtained
1823 from a non-main arena. This is only set immediately before handing
1824 the chunk to the user, if necessary. */
1825 #define NON_MAIN_ARENA 0x4
1827 /* check for chunk from non-main arena */
1828 #define chunk_non_main_arena(p) ((p)->size & NON_MAIN_ARENA)
1832 Bits to mask off when extracting size
1834 Note: IS_MMAPPED is intentionally not masked off from size field in
1835 macros for which mmapped chunks should never be seen. This should
1836 cause helpful core dumps to occur if it is tried by accident by
1837 people extending or adapting this malloc.
1839 #define SIZE_BITS (PREV_INUSE|IS_MMAPPED|NON_MAIN_ARENA)
1841 /* Get size, ignoring use bits */
1842 #define chunksize(p) ((p)->size & ~(SIZE_BITS))
1845 /* Ptr to next physical malloc_chunk. */
1846 #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~SIZE_BITS) ))
1848 /* Ptr to previous physical malloc_chunk */
1849 #define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))
1851 /* Treat space at ptr + offset as a chunk */
1852 #define chunk_at_offset(p, s) ((mchunkptr)(((char*)(p)) + (s)))
1854 /* extract p's inuse bit */
1856 ((((mchunkptr)(((char*)(p))+((p)->size & ~SIZE_BITS)))->size) & PREV_INUSE)
1858 /* set/clear chunk as being inuse without otherwise disturbing */
1859 #define set_inuse(p)\
1860 ((mchunkptr)(((char*)(p)) + ((p)->size & ~SIZE_BITS)))->size |= PREV_INUSE
1862 #define clear_inuse(p)\
1863 ((mchunkptr)(((char*)(p)) + ((p)->size & ~SIZE_BITS)))->size &= ~(PREV_INUSE)
1866 /* check/set/clear inuse bits in known places */
1867 #define inuse_bit_at_offset(p, s)\
1868 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)
1870 #define set_inuse_bit_at_offset(p, s)\
1871 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)
1873 #define clear_inuse_bit_at_offset(p, s)\
1874 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))
1877 /* Set size at head, without disturbing its use bit */
1878 #define set_head_size(p, s) ((p)->size = (((p)->size & SIZE_BITS) | (s)))
1880 /* Set size/use field */
1881 #define set_head(p, s) ((p)->size = (s))
1883 /* Set size at footer (only when chunk is not in use) */
1884 #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))
1888 -------------------- Internal data structures --------------------
1890 All internal state is held in an instance of malloc_state defined
1891 below. There are no other static variables, except in two optional
1893 * If USE_MALLOC_LOCK is defined, the mALLOC_MUTEx declared above.
1894 * If HAVE_MMAP is true, but mmap doesn't support
1895 MAP_ANONYMOUS, a dummy file descriptor for mmap.
1897 Beware of lots of tricks that minimize the total bookkeeping space
1898 requirements. The result is a little over 1K bytes (for 4byte
1899 pointers and size_t.)
1905 An array of bin headers for free chunks. Each bin is doubly
1906 linked. The bins are approximately proportionally (log) spaced.
1907 There are a lot of these bins (128). This may look excessive, but
1908 works very well in practice. Most bins hold sizes that are
1909 unusual as malloc request sizes, but are more usual for fragments
1910 and consolidated sets of chunks, which is what these bins hold, so
1911 they can be found quickly. All procedures maintain the invariant
1912 that no consolidated chunk physically borders another one, so each
1913 chunk in a list is known to be preceeded and followed by either
1914 inuse chunks or the ends of memory.
1916 Chunks in bins are kept in size order, with ties going to the
1917 approximately least recently used chunk. Ordering isn't needed
1918 for the small bins, which all contain the same-sized chunks, but
1919 facilitates best-fit allocation for larger chunks. These lists
1920 are just sequential. Keeping them in order almost never requires
1921 enough traversal to warrant using fancier ordered data
1924 Chunks of the same size are linked with the most
1925 recently freed at the front, and allocations are taken from the
1926 back. This results in LRU (FIFO) allocation order, which tends
1927 to give each chunk an equal opportunity to be consolidated with
1928 adjacent freed chunks, resulting in larger free chunks and less
1931 To simplify use in double-linked lists, each bin header acts
1932 as a malloc_chunk. This avoids special-casing for headers.
1933 But to conserve space and improve locality, we allocate
1934 only the fd/bk pointers of bins, and then use repositioning tricks
1935 to treat these as the fields of a malloc_chunk*.
1938 typedef struct malloc_chunk
* mbinptr
;
1940 /* addressing -- note that bin_at(0) does not exist */
1941 #define bin_at(m, i) ((mbinptr)((char*)&((m)->bins[(i)<<1]) - (SIZE_SZ<<1)))
1943 /* analog of ++bin */
1944 #define next_bin(b) ((mbinptr)((char*)(b) + (sizeof(mchunkptr)<<1)))
1946 /* Reminders about list directionality within bins */
1947 #define first(b) ((b)->fd)
1948 #define last(b) ((b)->bk)
1950 /* Take a chunk off a bin list */
1951 #define unlink(P, BK, FD) { \
1961 Bins for sizes < 512 bytes contain chunks of all the same size, spaced
1962 8 bytes apart. Larger bins are approximately logarithmically spaced:
1968 4 bins of size 32768
1969 2 bins of size 262144
1970 1 bin of size what's left
1972 There is actually a little bit of slop in the numbers in bin_index
1973 for the sake of speed. This makes no difference elsewhere.
1975 The bins top out around 1MB because we expect to service large
1980 #define NSMALLBINS 64
1981 #define SMALLBIN_WIDTH 8
1982 #define MIN_LARGE_SIZE 512
1984 #define in_smallbin_range(sz) \
1985 ((unsigned long)(sz) < (unsigned long)MIN_LARGE_SIZE)
1987 #define smallbin_index(sz) (((unsigned)(sz)) >> 3)
1989 #define largebin_index(sz) \
1990 (((((unsigned long)(sz)) >> 6) <= 32)? 56 + (((unsigned long)(sz)) >> 6): \
1991 ((((unsigned long)(sz)) >> 9) <= 20)? 91 + (((unsigned long)(sz)) >> 9): \
1992 ((((unsigned long)(sz)) >> 12) <= 10)? 110 + (((unsigned long)(sz)) >> 12): \
1993 ((((unsigned long)(sz)) >> 15) <= 4)? 119 + (((unsigned long)(sz)) >> 15): \
1994 ((((unsigned long)(sz)) >> 18) <= 2)? 124 + (((unsigned long)(sz)) >> 18): \
1997 #define bin_index(sz) \
1998 ((in_smallbin_range(sz)) ? smallbin_index(sz) : largebin_index(sz))
2004 All remainders from chunk splits, as well as all returned chunks,
2005 are first placed in the "unsorted" bin. They are then placed
2006 in regular bins after malloc gives them ONE chance to be used before
2007 binning. So, basically, the unsorted_chunks list acts as a queue,
2008 with chunks being placed on it in free (and malloc_consolidate),
2009 and taken off (to be either used or placed in bins) in malloc.
2011 The NON_MAIN_ARENA flag is never set for unsorted chunks, so it
2012 does not have to be taken into account in size comparisons.
2015 /* The otherwise unindexable 1-bin is used to hold unsorted chunks. */
2016 #define unsorted_chunks(M) (bin_at(M, 1))
2021 The top-most available chunk (i.e., the one bordering the end of
2022 available memory) is treated specially. It is never included in
2023 any bin, is used only if no other chunk is available, and is
2024 released back to the system if it is very large (see
2025 M_TRIM_THRESHOLD). Because top initially
2026 points to its own bin with initial zero size, thus forcing
2027 extension on the first malloc request, we avoid having any special
2028 code in malloc to check whether it even exists yet. But we still
2029 need to do so when getting memory from system, so we make
2030 initial_top treat the bin as a legal but unusable chunk during the
2031 interval between initialization and the first call to
2032 sYSMALLOc. (This is somewhat delicate, since it relies on
2033 the 2 preceding words to be zero during this interval as well.)
2036 /* Conveniently, the unsorted bin can be used as dummy top on first call */
2037 #define initial_top(M) (unsorted_chunks(M))
2042 To help compensate for the large number of bins, a one-level index
2043 structure is used for bin-by-bin searching. `binmap' is a
2044 bitvector recording whether bins are definitely empty so they can
2045 be skipped over during during traversals. The bits are NOT always
2046 cleared as soon as bins are empty, but instead only
2047 when they are noticed to be empty during traversal in malloc.
2050 /* Conservatively use 32 bits per map word, even if on 64bit system */
2051 #define BINMAPSHIFT 5
2052 #define BITSPERMAP (1U << BINMAPSHIFT)
2053 #define BINMAPSIZE (NBINS / BITSPERMAP)
2055 #define idx2block(i) ((i) >> BINMAPSHIFT)
2056 #define idx2bit(i) ((1U << ((i) & ((1U << BINMAPSHIFT)-1))))
2058 #define mark_bin(m,i) ((m)->binmap[idx2block(i)] |= idx2bit(i))
2059 #define unmark_bin(m,i) ((m)->binmap[idx2block(i)] &= ~(idx2bit(i)))
2060 #define get_binmap(m,i) ((m)->binmap[idx2block(i)] & idx2bit(i))
2065 An array of lists holding recently freed small chunks. Fastbins
2066 are not doubly linked. It is faster to single-link them, and
2067 since chunks are never removed from the middles of these lists,
2068 double linking is not necessary. Also, unlike regular bins, they
2069 are not even processed in FIFO order (they use faster LIFO) since
2070 ordering doesn't much matter in the transient contexts in which
2071 fastbins are normally used.
2073 Chunks in fastbins keep their inuse bit set, so they cannot
2074 be consolidated with other free chunks. malloc_consolidate
2075 releases all chunks in fastbins and consolidates them with
2079 typedef struct malloc_chunk
* mfastbinptr
;
2081 /* offset 2 to use otherwise unindexable first 2 bins */
2082 #define fastbin_index(sz) ((((unsigned int)(sz)) >> 3) - 2)
2084 /* The maximum fastbin request size we support */
2085 #define MAX_FAST_SIZE 80
2087 #define NFASTBINS (fastbin_index(request2size(MAX_FAST_SIZE))+1)
2090 FASTBIN_CONSOLIDATION_THRESHOLD is the size of a chunk in free()
2091 that triggers automatic consolidation of possibly-surrounding
2092 fastbin chunks. This is a heuristic, so the exact value should not
2093 matter too much. It is defined at half the default trim threshold as a
2094 compromise heuristic to only attempt consolidation if it is likely
2095 to lead to trimming. However, it is not dynamically tunable, since
2096 consolidation reduces fragmentation surrounding large chunks even
2097 if trimming is not used.
2100 #define FASTBIN_CONSOLIDATION_THRESHOLD (65536UL)
2103 Since the lowest 2 bits in max_fast don't matter in size comparisons,
2104 they are used as flags.
2108 FASTCHUNKS_BIT held in max_fast indicates that there are probably
2109 some fastbin chunks. It is set true on entering a chunk into any
2110 fastbin, and cleared only in malloc_consolidate.
2112 The truth value is inverted so that have_fastchunks will be true
2113 upon startup (since statics are zero-filled), simplifying
2114 initialization checks.
2117 #define FASTCHUNKS_BIT (1U)
2119 #define have_fastchunks(M) (((M)->max_fast & FASTCHUNKS_BIT) == 0)
2120 #define clear_fastchunks(M) ((M)->max_fast |= FASTCHUNKS_BIT)
2121 #define set_fastchunks(M) ((M)->max_fast &= ~FASTCHUNKS_BIT)
2124 NONCONTIGUOUS_BIT indicates that MORECORE does not return contiguous
2125 regions. Otherwise, contiguity is exploited in merging together,
2126 when possible, results from consecutive MORECORE calls.
2128 The initial value comes from MORECORE_CONTIGUOUS, but is
2129 changed dynamically if mmap is ever used as an sbrk substitute.
2132 #define NONCONTIGUOUS_BIT (2U)
2134 #define contiguous(M) (((M)->max_fast & NONCONTIGUOUS_BIT) == 0)
2135 #define noncontiguous(M) (((M)->max_fast & NONCONTIGUOUS_BIT) != 0)
2136 #define set_noncontiguous(M) ((M)->max_fast |= NONCONTIGUOUS_BIT)
2137 #define set_contiguous(M) ((M)->max_fast &= ~NONCONTIGUOUS_BIT)
2140 Set value of max_fast.
2141 Use impossibly small value if 0.
2142 Precondition: there are no existing fastbin chunks.
2143 Setting the value clears fastchunk bit but preserves noncontiguous bit.
2146 #define set_max_fast(M, s) \
2147 (M)->max_fast = (((s) == 0)? SMALLBIN_WIDTH: request2size(s)) | \
2149 ((M)->max_fast & NONCONTIGUOUS_BIT)
2153 ----------- Internal state representation and initialization -----------
2156 struct malloc_state
{
2157 /* Serialize access. */
2160 /* Statistics for locking. Only used if THREAD_STATS is defined. */
2161 long stat_lock_direct
, stat_lock_loop
, stat_lock_wait
;
2162 long pad0_
[1]; /* try to give the mutex its own cacheline */
2164 /* The maximum chunk size to be eligible for fastbin */
2165 INTERNAL_SIZE_T max_fast
; /* low 2 bits used as flags */
2168 mfastbinptr fastbins
[NFASTBINS
];
2170 /* Base of the topmost chunk -- not otherwise kept in a bin */
2173 /* The remainder from the most recent split of a small request */
2174 mchunkptr last_remainder
;
2176 /* Normal bins packed as described above */
2177 mchunkptr bins
[NBINS
* 2];
2179 /* Bitmap of bins */
2180 unsigned int binmap
[BINMAPSIZE
];
2183 struct malloc_state
*next
;
2185 /* Memory allocated from the system in this arena. */
2186 INTERNAL_SIZE_T system_mem
;
2187 INTERNAL_SIZE_T max_system_mem
;
2191 /* Tunable parameters */
2192 unsigned long trim_threshold
;
2193 INTERNAL_SIZE_T top_pad
;
2194 INTERNAL_SIZE_T mmap_threshold
;
2196 /* Memory map support */
2201 /* Cache malloc_getpagesize */
2202 unsigned int pagesize
;
2205 INTERNAL_SIZE_T mmapped_mem
;
2206 /*INTERNAL_SIZE_T sbrked_mem;*/
2207 /*INTERNAL_SIZE_T max_sbrked_mem;*/
2208 INTERNAL_SIZE_T max_mmapped_mem
;
2209 INTERNAL_SIZE_T max_total_mem
; /* only kept for NO_THREADS */
2211 /* First address handed out by MORECORE/sbrk. */
2215 /* There are several instances of this struct ("arenas") in this
2216 malloc. If you are adapting this malloc in a way that does NOT use
2217 a static or mmapped malloc_state, you MUST explicitly zero-fill it
2218 before using. This malloc relies on the property that malloc_state
2219 is initialized to all zeroes (as is true of C statics). */
2221 static struct malloc_state main_arena
;
2223 /* There is only one instance of the malloc parameters. */
2225 static struct malloc_par mp_
;
2228 Initialize a malloc_state struct.
2230 This is called only from within malloc_consolidate, which needs
2231 be called in the same contexts anyway. It is never called directly
2232 outside of malloc_consolidate because some optimizing compilers try
2233 to inline it at all call points, which turns out not to be an
2234 optimization at all. (Inlining it in malloc_consolidate is fine though.)
2238 static void malloc_init_state(mstate av
)
2240 static void malloc_init_state(av
) mstate av
;
2246 /* Establish circular links for normal bins */
2247 for (i
= 1; i
< NBINS
; ++i
) {
2249 bin
->fd
= bin
->bk
= bin
;
2252 #if MORECORE_CONTIGUOUS
2253 if (av
!= &main_arena
)
2255 set_noncontiguous(av
);
2257 set_max_fast(av
, DEFAULT_MXFAST
);
2259 av
->top
= initial_top(av
);
2263 Other internal utilities operating on mstates
2267 static Void_t
* sYSMALLOc(INTERNAL_SIZE_T
, mstate
);
2268 static int sYSTRIm(size_t, mstate
);
2269 static void malloc_consolidate(mstate
);
2270 static Void_t
** iALLOc(mstate
, size_t, size_t*, int, Void_t
**);
2272 static Void_t
* sYSMALLOc();
2273 static int sYSTRIm();
2274 static void malloc_consolidate();
2275 static Void_t
** iALLOc();
2279 /* -------------- Early definitions for debugging hooks ---------------- */
2281 /* Define and initialize the hook variables. These weak definitions must
2282 appear before any use of the variables in a function (arena.c uses one). */
2283 #ifndef weak_variable
2285 #define weak_variable /**/
2287 /* In GNU libc we want the hook variables to be weak definitions to
2288 avoid a problem with Emacs. */
2289 #define weak_variable weak_function
2293 /* Forward declarations. */
2294 static Void_t
* malloc_hook_ini
__MALLOC_P ((size_t sz
,
2295 const __malloc_ptr_t caller
));
2296 static Void_t
* realloc_hook_ini
__MALLOC_P ((Void_t
* ptr
, size_t sz
,
2297 const __malloc_ptr_t caller
));
2298 static Void_t
* memalign_hook_ini
__MALLOC_P ((size_t alignment
, size_t sz
,
2299 const __malloc_ptr_t caller
));
2301 void weak_variable (*__malloc_initialize_hook
) __MALLOC_P ((void)) = NULL
;
2302 void weak_variable (*__free_hook
) __MALLOC_P ((__malloc_ptr_t __ptr
,
2303 const __malloc_ptr_t
)) = NULL
;
2304 __malloc_ptr_t
weak_variable (*__malloc_hook
)
2305 __MALLOC_P ((size_t __size
, const __malloc_ptr_t
)) = malloc_hook_ini
;
2306 __malloc_ptr_t
weak_variable (*__realloc_hook
)
2307 __MALLOC_P ((__malloc_ptr_t __ptr
, size_t __size
, const __malloc_ptr_t
))
2309 __malloc_ptr_t
weak_variable (*__memalign_hook
)
2310 __MALLOC_P ((size_t __alignment
, size_t __size
, const __malloc_ptr_t
))
2311 = memalign_hook_ini
;
2312 void weak_variable (*__after_morecore_hook
) __MALLOC_P ((void)) = NULL
;
2315 /* ------------------- Support for multiple arenas -------------------- */
2321 These routines make a number of assertions about the states
2322 of data structures that should be true at all times. If any
2323 are not true, it's very likely that a user program has somehow
2324 trashed memory. (It's also possible that there is a coding error
2325 in malloc. In which case, please report it!)
2330 #define check_chunk(A,P)
2331 #define check_free_chunk(A,P)
2332 #define check_inuse_chunk(A,P)
2333 #define check_remalloced_chunk(A,P,N)
2334 #define check_malloced_chunk(A,P,N)
2335 #define check_malloc_state(A)
2339 #define check_chunk(A,P) do_check_chunk(A,P)
2340 #define check_free_chunk(A,P) do_check_free_chunk(A,P)
2341 #define check_inuse_chunk(A,P) do_check_inuse_chunk(A,P)
2342 #define check_remalloced_chunk(A,P,N) do_check_remalloced_chunk(A,P,N)
2343 #define check_malloced_chunk(A,P,N) do_check_malloced_chunk(A,P,N)
2344 #define check_malloc_state(A) do_check_malloc_state(A)
2347 Properties of all chunks
2351 static void do_check_chunk(mstate av
, mchunkptr p
)
2353 static void do_check_chunk(av
, p
) mstate av
; mchunkptr p
;
2356 unsigned long sz
= chunksize(p
);
2357 /* min and max possible addresses assuming contiguous allocation */
2358 char* max_address
= (char*)(av
->top
) + chunksize(av
->top
);
2359 char* min_address
= max_address
- av
->system_mem
;
2361 if (!chunk_is_mmapped(p
)) {
2363 /* Has legal address ... */
2365 if (contiguous(av
)) {
2366 assert(((char*)p
) >= min_address
);
2367 assert(((char*)p
+ sz
) <= ((char*)(av
->top
)));
2371 /* top size is always at least MINSIZE */
2372 assert((unsigned long)(sz
) >= MINSIZE
);
2373 /* top predecessor always marked inuse */
2374 assert(prev_inuse(p
));
2380 /* address is outside main heap */
2381 if (contiguous(av
) && av
->top
!= initial_top(av
)) {
2382 assert(((char*)p
) < min_address
|| ((char*)p
) > max_address
);
2384 /* chunk is page-aligned */
2385 assert(((p
->prev_size
+ sz
) & (mp_
.pagesize
-1)) == 0);
2386 /* mem is aligned */
2387 assert(aligned_OK(chunk2mem(p
)));
2389 /* force an appropriate assert violation if debug set */
2390 assert(!chunk_is_mmapped(p
));
2396 Properties of free chunks
2400 static void do_check_free_chunk(mstate av
, mchunkptr p
)
2402 static void do_check_free_chunk(av
, p
) mstate av
; mchunkptr p
;
2405 INTERNAL_SIZE_T sz
= p
->size
& ~(PREV_INUSE
|NON_MAIN_ARENA
);
2406 mchunkptr next
= chunk_at_offset(p
, sz
);
2408 do_check_chunk(av
, p
);
2410 /* Chunk must claim to be free ... */
2412 assert (!chunk_is_mmapped(p
));
2414 /* Unless a special marker, must have OK fields */
2415 if ((unsigned long)(sz
) >= MINSIZE
)
2417 assert((sz
& MALLOC_ALIGN_MASK
) == 0);
2418 assert(aligned_OK(chunk2mem(p
)));
2419 /* ... matching footer field */
2420 assert(next
->prev_size
== sz
);
2421 /* ... and is fully consolidated */
2422 assert(prev_inuse(p
));
2423 assert (next
== av
->top
|| inuse(next
));
2425 /* ... and has minimally sane links */
2426 assert(p
->fd
->bk
== p
);
2427 assert(p
->bk
->fd
== p
);
2429 else /* markers are always of size SIZE_SZ */
2430 assert(sz
== SIZE_SZ
);
2434 Properties of inuse chunks
2438 static void do_check_inuse_chunk(mstate av
, mchunkptr p
)
2440 static void do_check_inuse_chunk(av
, p
) mstate av
; mchunkptr p
;
2445 do_check_chunk(av
, p
);
2447 if (chunk_is_mmapped(p
))
2448 return; /* mmapped chunks have no next/prev */
2450 /* Check whether it claims to be in use ... */
2453 next
= next_chunk(p
);
2455 /* ... and is surrounded by OK chunks.
2456 Since more things can be checked with free chunks than inuse ones,
2457 if an inuse chunk borders them and debug is on, it's worth doing them.
2459 if (!prev_inuse(p
)) {
2460 /* Note that we cannot even look at prev unless it is not inuse */
2461 mchunkptr prv
= prev_chunk(p
);
2462 assert(next_chunk(prv
) == p
);
2463 do_check_free_chunk(av
, prv
);
2466 if (next
== av
->top
) {
2467 assert(prev_inuse(next
));
2468 assert(chunksize(next
) >= MINSIZE
);
2470 else if (!inuse(next
))
2471 do_check_free_chunk(av
, next
);
2475 Properties of chunks recycled from fastbins
2479 static void do_check_remalloced_chunk(mstate av
, mchunkptr p
, INTERNAL_SIZE_T s
)
2481 static void do_check_remalloced_chunk(av
, p
, s
)
2482 mstate av
; mchunkptr p
; INTERNAL_SIZE_T s
;
2485 INTERNAL_SIZE_T sz
= p
->size
& ~(PREV_INUSE
|NON_MAIN_ARENA
);
2487 if (!chunk_is_mmapped(p
)) {
2488 assert(av
== arena_for_chunk(p
));
2489 if (chunk_non_main_arena(p
))
2490 assert(av
!= &main_arena
);
2492 assert(av
== &main_arena
);
2495 do_check_inuse_chunk(av
, p
);
2497 /* Legal size ... */
2498 assert((sz
& MALLOC_ALIGN_MASK
) == 0);
2499 assert((unsigned long)(sz
) >= MINSIZE
);
2500 /* ... and alignment */
2501 assert(aligned_OK(chunk2mem(p
)));
2502 /* chunk is less than MINSIZE more than request */
2503 assert((long)(sz
) - (long)(s
) >= 0);
2504 assert((long)(sz
) - (long)(s
+ MINSIZE
) < 0);
2508 Properties of nonrecycled chunks at the point they are malloced
2512 static void do_check_malloced_chunk(mstate av
, mchunkptr p
, INTERNAL_SIZE_T s
)
2514 static void do_check_malloced_chunk(av
, p
, s
)
2515 mstate av
; mchunkptr p
; INTERNAL_SIZE_T s
;
2518 /* same as recycled case ... */
2519 do_check_remalloced_chunk(av
, p
, s
);
2522 ... plus, must obey implementation invariant that prev_inuse is
2523 always true of any allocated chunk; i.e., that each allocated
2524 chunk borders either a previously allocated and still in-use
2525 chunk, or the base of its memory arena. This is ensured
2526 by making all allocations from the the `lowest' part of any found
2527 chunk. This does not necessarily hold however for chunks
2528 recycled via fastbins.
2531 assert(prev_inuse(p
));
2536 Properties of malloc_state.
2538 This may be useful for debugging malloc, as well as detecting user
2539 programmer errors that somehow write into malloc_state.
2541 If you are extending or experimenting with this malloc, you can
2542 probably figure out how to hack this routine to print out or
2543 display chunk addresses, sizes, bins, and other instrumentation.
2546 static void do_check_malloc_state(mstate av
)
2552 unsigned int binbit
;
2555 INTERNAL_SIZE_T size
;
2556 unsigned long total
= 0;
2559 /* internal size_t must be no wider than pointer type */
2560 assert(sizeof(INTERNAL_SIZE_T
) <= sizeof(char*));
2562 /* alignment is a power of 2 */
2563 assert((MALLOC_ALIGNMENT
& (MALLOC_ALIGNMENT
-1)) == 0);
2565 /* cannot run remaining checks until fully initialized */
2566 if (av
->top
== 0 || av
->top
== initial_top(av
))
2569 /* pagesize is a power of 2 */
2570 assert((mp_
.pagesize
& (mp_
.pagesize
-1)) == 0);
2572 /* A contiguous main_arena is consistent with sbrk_base. */
2573 if (av
== &main_arena
&& contiguous(av
))
2574 assert((char*)mp_
.sbrk_base
+ av
->system_mem
==
2575 (char*)av
->top
+ chunksize(av
->top
));
2577 /* properties of fastbins */
2579 /* max_fast is in allowed range */
2580 assert((av
->max_fast
& ~1) <= request2size(MAX_FAST_SIZE
));
2582 max_fast_bin
= fastbin_index(av
->max_fast
);
2584 for (i
= 0; i
< NFASTBINS
; ++i
) {
2585 p
= av
->fastbins
[i
];
2587 /* all bins past max_fast are empty */
2588 if (i
> max_fast_bin
)
2592 /* each chunk claims to be inuse */
2593 do_check_inuse_chunk(av
, p
);
2594 total
+= chunksize(p
);
2595 /* chunk belongs in this bin */
2596 assert(fastbin_index(chunksize(p
)) == i
);
2602 assert(have_fastchunks(av
));
2603 else if (!have_fastchunks(av
))
2606 /* check normal bins */
2607 for (i
= 1; i
< NBINS
; ++i
) {
2610 /* binmap is accurate (except for bin 1 == unsorted_chunks) */
2612 binbit
= get_binmap(av
,i
);
2613 empty
= last(b
) == b
;
2620 for (p
= last(b
); p
!= b
; p
= p
->bk
) {
2621 /* each chunk claims to be free */
2622 do_check_free_chunk(av
, p
);
2623 size
= chunksize(p
);
2626 /* chunk belongs in bin */
2627 idx
= bin_index(size
);
2629 /* lists are sorted */
2630 assert(p
->bk
== b
||
2631 (unsigned long)chunksize(p
->bk
) >= (unsigned long)chunksize(p
));
2633 /* chunk is followed by a legal chain of inuse chunks */
2634 for (q
= next_chunk(p
);
2635 (q
!= av
->top
&& inuse(q
) &&
2636 (unsigned long)(chunksize(q
)) >= MINSIZE
);
2638 do_check_inuse_chunk(av
, q
);
2642 /* top chunk is OK */
2643 check_chunk(av
, av
->top
);
2645 /* sanity checks for statistics */
2648 assert(total
<= (unsigned long)(mp_
.max_total_mem
));
2649 assert(mp_
.n_mmaps
>= 0);
2651 assert(mp_
.n_mmaps
<= mp_
.n_mmaps_max
);
2652 assert(mp_
.n_mmaps
<= mp_
.max_n_mmaps
);
2654 assert((unsigned long)(av
->system_mem
) <=
2655 (unsigned long)(av
->max_system_mem
));
2657 assert((unsigned long)(mp_
.mmapped_mem
) <=
2658 (unsigned long)(mp_
.max_mmapped_mem
));
2661 assert((unsigned long)(mp_
.max_total_mem
) >=
2662 (unsigned long)(mp_
.mmapped_mem
) + (unsigned long)(av
->system_mem
));
2668 /* ----------------- Support for debugging hooks -------------------- */
2672 /* ----------- Routines dealing with system allocation -------------- */
2675 sysmalloc handles malloc cases requiring more memory from the system.
2676 On entry, it is assumed that av->top does not have enough
2677 space to service request for nb bytes, thus requiring that av->top
2678 be extended or replaced.
2682 static Void_t
* sYSMALLOc(INTERNAL_SIZE_T nb
, mstate av
)
2684 static Void_t
* sYSMALLOc(nb
, av
) INTERNAL_SIZE_T nb
; mstate av
;
2687 mchunkptr old_top
; /* incoming value of av->top */
2688 INTERNAL_SIZE_T old_size
; /* its size */
2689 char* old_end
; /* its end address */
2691 long size
; /* arg to first MORECORE or mmap call */
2692 char* brk
; /* return value from MORECORE */
2694 long correction
; /* arg to 2nd MORECORE call */
2695 char* snd_brk
; /* 2nd return val */
2697 INTERNAL_SIZE_T front_misalign
; /* unusable bytes at front of new space */
2698 INTERNAL_SIZE_T end_misalign
; /* partial page left at end of new space */
2699 char* aligned_brk
; /* aligned offset into brk */
2701 mchunkptr p
; /* the allocated/returned chunk */
2702 mchunkptr remainder
; /* remainder from allocation */
2703 unsigned long remainder_size
; /* its size */
2705 unsigned long sum
; /* for updating stats */
2707 size_t pagemask
= mp_
.pagesize
- 1;
2713 If have mmap, and the request size meets the mmap threshold, and
2714 the system supports mmap, and there are few enough currently
2715 allocated mmapped regions, try to directly map this request
2716 rather than expanding top.
2719 if ((unsigned long)(nb
) >= (unsigned long)(mp_
.mmap_threshold
) &&
2720 (mp_
.n_mmaps
< mp_
.n_mmaps_max
)) {
2722 char* mm
; /* return value from mmap call*/
2725 Round up size to nearest page. For mmapped chunks, the overhead
2726 is one SIZE_SZ unit larger than for normal chunks, because there
2727 is no following chunk whose prev_size field could be used.
2729 size
= (nb
+ SIZE_SZ
+ MALLOC_ALIGN_MASK
+ pagemask
) & ~pagemask
;
2731 /* Don't try if size wraps around 0 */
2732 if ((unsigned long)(size
) > (unsigned long)(nb
)) {
2734 mm
= (char*)(MMAP(0, size
, PROT_READ
|PROT_WRITE
, MAP_PRIVATE
));
2736 if (mm
!= MAP_FAILED
) {
2739 The offset to the start of the mmapped region is stored
2740 in the prev_size field of the chunk. This allows us to adjust
2741 returned start address to meet alignment requirements here
2742 and in memalign(), and still be able to compute proper
2743 address argument for later munmap in free() and realloc().
2746 front_misalign
= (INTERNAL_SIZE_T
)chunk2mem(mm
) & MALLOC_ALIGN_MASK
;
2747 if (front_misalign
> 0) {
2748 correction
= MALLOC_ALIGNMENT
- front_misalign
;
2749 p
= (mchunkptr
)(mm
+ correction
);
2750 p
->prev_size
= correction
;
2751 set_head(p
, (size
- correction
) |IS_MMAPPED
);
2755 set_head(p
, size
|IS_MMAPPED
);
2758 /* update statistics */
2760 if (++mp_
.n_mmaps
> mp_
.max_n_mmaps
)
2761 mp_
.max_n_mmaps
= mp_
.n_mmaps
;
2763 sum
= mp_
.mmapped_mem
+= size
;
2764 if (sum
> (unsigned long)(mp_
.max_mmapped_mem
))
2765 mp_
.max_mmapped_mem
= sum
;
2767 sum
+= av
->system_mem
;
2768 if (sum
> (unsigned long)(mp_
.max_total_mem
))
2769 mp_
.max_total_mem
= sum
;
2774 return chunk2mem(p
);
2780 /* Record incoming configuration of top */
2783 old_size
= chunksize(old_top
);
2784 old_end
= (char*)(chunk_at_offset(old_top
, old_size
));
2786 brk
= snd_brk
= (char*)(MORECORE_FAILURE
);
2789 If not the first time through, we require old_size to be
2790 at least MINSIZE and to have prev_inuse set.
2793 assert((old_top
== initial_top(av
) && old_size
== 0) ||
2794 ((unsigned long) (old_size
) >= MINSIZE
&&
2795 prev_inuse(old_top
) &&
2796 ((unsigned long)old_end
& pagemask
) == 0));
2798 /* Precondition: not enough current space to satisfy nb request */
2799 assert((unsigned long)(old_size
) < (unsigned long)(nb
+ MINSIZE
));
2801 /* Precondition: all fastbins are consolidated */
2802 assert(!have_fastchunks(av
));
2805 if (av
!= &main_arena
) {
2807 heap_info
*old_heap
, *heap
;
2808 size_t old_heap_size
;
2810 /* First try to extend the current heap. */
2811 old_heap
= heap_for_ptr(old_top
);
2812 old_heap_size
= old_heap
->size
;
2813 if (grow_heap(old_heap
, MINSIZE
+ nb
- old_size
) == 0) {
2814 av
->system_mem
+= old_heap
->size
- old_heap_size
;
2815 arena_mem
+= old_heap
->size
- old_heap_size
;
2817 if(mmapped_mem
+ arena_mem
+ sbrked_mem
> max_total_mem
)
2818 max_total_mem
= mmapped_mem
+ arena_mem
+ sbrked_mem
;
2820 set_head(old_top
, (((char *)old_heap
+ old_heap
->size
) - (char *)old_top
)
2823 else if ((heap
= new_heap(nb
+ (MINSIZE
+ sizeof(*heap
)), mp_
.top_pad
))) {
2824 /* Use a newly allocated heap. */
2826 heap
->prev
= old_heap
;
2827 av
->system_mem
+= heap
->size
;
2828 arena_mem
+= heap
->size
;
2830 if((unsigned long)(mmapped_mem
+ arena_mem
+ sbrked_mem
) > max_total_mem
)
2831 max_total_mem
= mmapped_mem
+ arena_mem
+ sbrked_mem
;
2833 /* Set up the new top. */
2834 top(av
) = chunk_at_offset(heap
, sizeof(*heap
));
2835 set_head(top(av
), (heap
->size
- sizeof(*heap
)) | PREV_INUSE
);
2837 /* Setup fencepost and free the old top chunk. */
2838 /* The fencepost takes at least MINSIZE bytes, because it might
2839 become the top chunk again later. Note that a footer is set
2840 up, too, although the chunk is marked in use. */
2841 old_size
-= MINSIZE
;
2842 set_head(chunk_at_offset(old_top
, old_size
+ 2*SIZE_SZ
), 0|PREV_INUSE
);
2843 if (old_size
>= MINSIZE
) {
2844 set_head(chunk_at_offset(old_top
, old_size
), (2*SIZE_SZ
)|PREV_INUSE
);
2845 set_foot(chunk_at_offset(old_top
, old_size
), (2*SIZE_SZ
));
2846 set_head(old_top
, old_size
|PREV_INUSE
|NON_MAIN_ARENA
);
2847 _int_free(av
, chunk2mem(old_top
));
2849 set_head(old_top
, (old_size
+ 2*SIZE_SZ
)|PREV_INUSE
);
2850 set_foot(old_top
, (old_size
+ 2*SIZE_SZ
));
2854 } else { /* av == main_arena */
2857 /* Request enough space for nb + pad + overhead */
2859 size
= nb
+ mp_
.top_pad
+ MINSIZE
;
2862 If contiguous, we can subtract out existing space that we hope to
2863 combine with new space. We add it back later only if
2864 we don't actually get contiguous space.
2871 Round to a multiple of page size.
2872 If MORECORE is not contiguous, this ensures that we only call it
2873 with whole-page arguments. And if MORECORE is contiguous and
2874 this is not first time through, this preserves page-alignment of
2875 previous calls. Otherwise, we correct to page-align below.
2878 size
= (size
+ pagemask
) & ~pagemask
;
2881 Don't try to call MORECORE if argument is so big as to appear
2882 negative. Note that since mmap takes size_t arg, it may succeed
2883 below even if we cannot call MORECORE.
2887 brk
= (char*)(MORECORE(size
));
2889 if (brk
!= (char*)(MORECORE_FAILURE
)) {
2890 /* Call the `morecore' hook if necessary. */
2891 if (__after_morecore_hook
)
2892 (*__after_morecore_hook
) ();
2895 If have mmap, try using it as a backup when MORECORE fails or
2896 cannot be used. This is worth doing on systems that have "holes" in
2897 address space, so sbrk cannot extend to give contiguous space, but
2898 space is available elsewhere. Note that we ignore mmap max count
2899 and threshold limits, since the space will not be used as a
2900 segregated mmap region.
2904 /* Cannot merge with old top, so add its size back in */
2906 size
= (size
+ old_size
+ pagemask
) & ~pagemask
;
2908 /* If we are relying on mmap as backup, then use larger units */
2909 if ((unsigned long)(size
) < (unsigned long)(MMAP_AS_MORECORE_SIZE
))
2910 size
= MMAP_AS_MORECORE_SIZE
;
2912 /* Don't try if size wraps around 0 */
2913 if ((unsigned long)(size
) > (unsigned long)(nb
)) {
2915 char *mbrk
= (char*)(MMAP(0, size
, PROT_READ
|PROT_WRITE
, MAP_PRIVATE
));
2917 if (mbrk
!= MAP_FAILED
) {
2919 /* We do not need, and cannot use, another sbrk call to find end */
2921 snd_brk
= brk
+ size
;
2924 Record that we no longer have a contiguous sbrk region.
2925 After the first time mmap is used as backup, we do not
2926 ever rely on contiguous space since this could incorrectly
2929 set_noncontiguous(av
);
2935 if (brk
!= (char*)(MORECORE_FAILURE
)) {
2936 if (mp_
.sbrk_base
== 0)
2937 mp_
.sbrk_base
= brk
;
2938 av
->system_mem
+= size
;
2941 If MORECORE extends previous space, we can likewise extend top size.
2944 if (brk
== old_end
&& snd_brk
== (char*)(MORECORE_FAILURE
))
2945 set_head(old_top
, (size
+ old_size
) | PREV_INUSE
);
2947 else if (contiguous(av
) && old_size
&& brk
< old_end
) {
2948 /* Oops! Someone else killed our space.. Can't touch anything. */
2953 Otherwise, make adjustments:
2955 * If the first time through or noncontiguous, we need to call sbrk
2956 just to find out where the end of memory lies.
2958 * We need to ensure that all returned chunks from malloc will meet
2961 * If there was an intervening foreign sbrk, we need to adjust sbrk
2962 request size to account for fact that we will not be able to
2963 combine new space with existing space in old_top.
2965 * Almost all systems internally allocate whole pages at a time, in
2966 which case we might as well use the whole last page of request.
2967 So we allocate enough more memory to hit a page boundary now,
2968 which in turn causes future contiguous calls to page-align.
2972 /* Count foreign sbrk as system_mem. */
2974 av
->system_mem
+= brk
- old_end
;
2980 /* handle contiguous cases */
2981 if (contiguous(av
)) {
2983 /* Guarantee alignment of first new chunk made from this space */
2985 front_misalign
= (INTERNAL_SIZE_T
)chunk2mem(brk
) & MALLOC_ALIGN_MASK
;
2986 if (front_misalign
> 0) {
2989 Skip over some bytes to arrive at an aligned position.
2990 We don't need to specially mark these wasted front bytes.
2991 They will never be accessed anyway because
2992 prev_inuse of av->top (and any chunk created from its start)
2993 is always true after initialization.
2996 correction
= MALLOC_ALIGNMENT
- front_misalign
;
2997 aligned_brk
+= correction
;
3001 If this isn't adjacent to existing space, then we will not
3002 be able to merge with old_top space, so must add to 2nd request.
3005 correction
+= old_size
;
3007 /* Extend the end address to hit a page boundary */
3008 end_misalign
= (INTERNAL_SIZE_T
)(brk
+ size
+ correction
);
3009 correction
+= ((end_misalign
+ pagemask
) & ~pagemask
) - end_misalign
;
3011 assert(correction
>= 0);
3012 snd_brk
= (char*)(MORECORE(correction
));
3015 If can't allocate correction, try to at least find out current
3016 brk. It might be enough to proceed without failing.
3018 Note that if second sbrk did NOT fail, we assume that space
3019 is contiguous with first sbrk. This is a safe assumption unless
3020 program is multithreaded but doesn't use locks and a foreign sbrk
3021 occurred between our first and second calls.
3024 if (snd_brk
== (char*)(MORECORE_FAILURE
)) {
3026 snd_brk
= (char*)(MORECORE(0));
3028 /* Call the `morecore' hook if necessary. */
3029 if (__after_morecore_hook
)
3030 (*__after_morecore_hook
) ();
3033 /* handle non-contiguous cases */
3035 /* MORECORE/mmap must correctly align */
3036 assert(((unsigned long)chunk2mem(brk
) & MALLOC_ALIGN_MASK
) == 0);
3038 /* Find out current end of memory */
3039 if (snd_brk
== (char*)(MORECORE_FAILURE
)) {
3040 snd_brk
= (char*)(MORECORE(0));
3044 /* Adjust top based on results of second sbrk */
3045 if (snd_brk
!= (char*)(MORECORE_FAILURE
)) {
3046 av
->top
= (mchunkptr
)aligned_brk
;
3047 set_head(av
->top
, (snd_brk
- aligned_brk
+ correction
) | PREV_INUSE
);
3048 av
->system_mem
+= correction
;
3051 If not the first time through, we either have a
3052 gap due to foreign sbrk or a non-contiguous region. Insert a
3053 double fencepost at old_top to prevent consolidation with space
3054 we don't own. These fenceposts are artificial chunks that are
3055 marked as inuse and are in any case too small to use. We need
3056 two to make sizes and alignments work out.
3059 if (old_size
!= 0) {
3061 Shrink old_top to insert fenceposts, keeping size a
3062 multiple of MALLOC_ALIGNMENT. We know there is at least
3063 enough space in old_top to do this.
3065 old_size
= (old_size
- 4*SIZE_SZ
) & ~MALLOC_ALIGN_MASK
;
3066 set_head(old_top
, old_size
| PREV_INUSE
);
3069 Note that the following assignments completely overwrite
3070 old_top when old_size was previously MINSIZE. This is
3071 intentional. We need the fencepost, even if old_top otherwise gets
3074 chunk_at_offset(old_top
, old_size
)->size
=
3075 (2*SIZE_SZ
)|PREV_INUSE
;
3077 chunk_at_offset(old_top
, old_size
+ 2*SIZE_SZ
)->size
=
3078 (2*SIZE_SZ
)|PREV_INUSE
;
3080 /* If possible, release the rest. */
3081 if (old_size
>= MINSIZE
) {
3082 _int_free(av
, chunk2mem(old_top
));
3089 /* Update statistics */
3091 sum
= av
->system_mem
+ mp_
.mmapped_mem
;
3092 if (sum
> (unsigned long)(mp_
.max_total_mem
))
3093 mp_
.max_total_mem
= sum
;
3098 } /* if (av != &main_arena) */
3100 if ((unsigned long)av
->system_mem
> (unsigned long)(av
->max_system_mem
))
3101 av
->max_system_mem
= av
->system_mem
;
3102 check_malloc_state(av
);
3104 /* finally, do the allocation */
3106 size
= chunksize(p
);
3108 /* check that one of the above allocation paths succeeded */
3109 if ((unsigned long)(size
) >= (unsigned long)(nb
+ MINSIZE
)) {
3110 remainder_size
= size
- nb
;
3111 remainder
= chunk_at_offset(p
, nb
);
3112 av
->top
= remainder
;
3113 set_head(p
, nb
| PREV_INUSE
| (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
3114 set_head(remainder
, remainder_size
| PREV_INUSE
);
3115 check_malloced_chunk(av
, p
, nb
);
3116 return chunk2mem(p
);
3119 /* catch all failure paths */
3120 MALLOC_FAILURE_ACTION
;
3126 sYSTRIm is an inverse of sorts to sYSMALLOc. It gives memory back
3127 to the system (via negative arguments to sbrk) if there is unused
3128 memory at the `high' end of the malloc pool. It is called
3129 automatically by free() when top space exceeds the trim
3130 threshold. It is also called by the public malloc_trim routine. It
3131 returns 1 if it actually released any memory, else 0.
3135 static int sYSTRIm(size_t pad
, mstate av
)
3137 static int sYSTRIm(pad
, av
) size_t pad
; mstate av
;
3140 long top_size
; /* Amount of top-most memory */
3141 long extra
; /* Amount to release */
3142 long released
; /* Amount actually released */
3143 char* current_brk
; /* address returned by pre-check sbrk call */
3144 char* new_brk
; /* address returned by post-check sbrk call */
3147 pagesz
= mp_
.pagesize
;
3148 top_size
= chunksize(av
->top
);
3150 /* Release in pagesize units, keeping at least one page */
3151 extra
= ((top_size
- pad
- MINSIZE
+ (pagesz
-1)) / pagesz
- 1) * pagesz
;
3156 Only proceed if end of memory is where we last set it.
3157 This avoids problems if there were foreign sbrk calls.
3159 current_brk
= (char*)(MORECORE(0));
3160 if (current_brk
== (char*)(av
->top
) + top_size
) {
3163 Attempt to release memory. We ignore MORECORE return value,
3164 and instead call again to find out where new end of memory is.
3165 This avoids problems if first call releases less than we asked,
3166 of if failure somehow altered brk value. (We could still
3167 encounter problems if it altered brk in some very bad way,
3168 but the only thing we can do is adjust anyway, which will cause
3169 some downstream failure.)
3173 /* Call the `morecore' hook if necessary. */
3174 if (__after_morecore_hook
)
3175 (*__after_morecore_hook
) ();
3176 new_brk
= (char*)(MORECORE(0));
3178 if (new_brk
!= (char*)MORECORE_FAILURE
) {
3179 released
= (long)(current_brk
- new_brk
);
3181 if (released
!= 0) {
3182 /* Success. Adjust top. */
3183 av
->system_mem
-= released
;
3184 set_head(av
->top
, (top_size
- released
) | PREV_INUSE
);
3185 check_malloc_state(av
);
3199 munmap_chunk(mchunkptr p
)
3201 munmap_chunk(p
) mchunkptr p
;
3204 INTERNAL_SIZE_T size
= chunksize(p
);
3207 assert (chunk_is_mmapped(p
));
3209 assert(! ((char*)p
>= mp_
.sbrk_base
&& (char*)p
< mp_
.sbrk_base
+ mp_
.sbrked_mem
));
3210 assert((mp_
.n_mmaps
> 0));
3212 assert(((p
->prev_size
+ size
) & (mp_
.pagesize
-1)) == 0);
3215 mp_
.mmapped_mem
-= (size
+ p
->prev_size
);
3217 ret
= munmap((char *)p
- p
->prev_size
, size
+ p
->prev_size
);
3219 /* munmap returns non-zero on failure */
3228 mremap_chunk(mchunkptr p
, size_t new_size
)
3230 mremap_chunk(p
, new_size
) mchunkptr p
; size_t new_size
;
3233 size_t page_mask
= mp_
.pagesize
- 1;
3234 INTERNAL_SIZE_T offset
= p
->prev_size
;
3235 INTERNAL_SIZE_T size
= chunksize(p
);
3238 assert (chunk_is_mmapped(p
));
3240 assert(! ((char*)p
>= mp_
.sbrk_base
&& (char*)p
< mp_
.sbrk_base
+ mp_
.sbrked_mem
));
3241 assert((mp_
.n_mmaps
> 0));
3243 assert(((size
+ offset
) & (mp_
.pagesize
-1)) == 0);
3245 /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
3246 new_size
= (new_size
+ offset
+ SIZE_SZ
+ page_mask
) & ~page_mask
;
3248 cp
= (char *)mremap((char *)p
- offset
, size
+ offset
, new_size
,
3251 if (cp
== MAP_FAILED
) return 0;
3253 p
= (mchunkptr
)(cp
+ offset
);
3255 assert(aligned_OK(chunk2mem(p
)));
3257 assert((p
->prev_size
== offset
));
3258 set_head(p
, (new_size
- offset
)|IS_MMAPPED
);
3260 mp_
.mmapped_mem
-= size
+ offset
;
3261 mp_
.mmapped_mem
+= new_size
;
3262 if ((unsigned long)mp_
.mmapped_mem
> (unsigned long)mp_
.max_mmapped_mem
)
3263 mp_
.max_mmapped_mem
= mp_
.mmapped_mem
;
3265 if ((unsigned long)(mp_
.mmapped_mem
+ arena_mem
+ main_arena
.system_mem
) >
3267 mp_
.max_total_mem
= mp_
.mmapped_mem
+ arena_mem
+ main_arena
.system_mem
;
3272 #endif /* HAVE_MREMAP */
3274 #endif /* HAVE_MMAP */
3276 /*------------------------ Public wrappers. --------------------------------*/
3279 public_mALLOc(size_t bytes
)
3284 __malloc_ptr_t (*hook
) __MALLOC_P ((size_t, __const __malloc_ptr_t
)) =
3287 return (*hook
)(bytes
, RETURN_ADDRESS (0));
3289 arena_get(ar_ptr
, bytes
);
3292 victim
= _int_malloc(ar_ptr
, bytes
);
3294 /* Maybe the failure is due to running out of mmapped areas. */
3295 if(ar_ptr
!= &main_arena
) {
3296 (void)mutex_unlock(&ar_ptr
->mutex
);
3297 (void)mutex_lock(&main_arena
.mutex
);
3298 victim
= _int_malloc(&main_arena
, bytes
);
3299 (void)mutex_unlock(&main_arena
.mutex
);
3302 /* ... or sbrk() has failed and there is still a chance to mmap() */
3303 ar_ptr
= arena_get2(ar_ptr
->next
? ar_ptr
: 0, bytes
);
3304 (void)mutex_unlock(&main_arena
.mutex
);
3306 victim
= _int_malloc(ar_ptr
, bytes
);
3307 (void)mutex_unlock(&ar_ptr
->mutex
);
3312 (void)mutex_unlock(&ar_ptr
->mutex
);
3313 assert(!victim
|| chunk_is_mmapped(mem2chunk(victim
)) ||
3314 ar_ptr
== arena_for_chunk(mem2chunk(victim
)));
3319 public_fREe(Void_t
* mem
)
3322 mchunkptr p
; /* chunk corresponding to mem */
3324 void (*hook
) __MALLOC_P ((__malloc_ptr_t
, __const __malloc_ptr_t
)) =
3327 (*hook
)(mem
, RETURN_ADDRESS (0));
3331 if (mem
== 0) /* free(0) has no effect */
3337 if (chunk_is_mmapped(p
)) /* release mmapped memory. */
3344 ar_ptr
= arena_for_chunk(p
);
3346 if(!mutex_trylock(&ar_ptr
->mutex
))
3347 ++(ar_ptr
->stat_lock_direct
);
3349 (void)mutex_lock(&ar_ptr
->mutex
);
3350 ++(ar_ptr
->stat_lock_wait
);
3353 (void)mutex_lock(&ar_ptr
->mutex
);
3355 _int_free(ar_ptr
, mem
);
3356 (void)mutex_unlock(&ar_ptr
->mutex
);
3360 public_rEALLOc(Void_t
* oldmem
, size_t bytes
)
3363 INTERNAL_SIZE_T nb
; /* padded request size */
3365 mchunkptr oldp
; /* chunk corresponding to oldmem */
3366 INTERNAL_SIZE_T oldsize
; /* its size */
3368 Void_t
* newp
; /* chunk to return */
3370 __malloc_ptr_t (*hook
) __MALLOC_P ((__malloc_ptr_t
, size_t,
3371 __const __malloc_ptr_t
)) =
3374 return (*hook
)(oldmem
, bytes
, RETURN_ADDRESS (0));
3376 #if REALLOC_ZERO_BYTES_FREES
3377 if (bytes
== 0 && oldmem
!= NULL
) { public_fREe(oldmem
); return 0; }
3380 /* realloc of null is supposed to be same as malloc */
3381 if (oldmem
== 0) return public_mALLOc(bytes
);
3383 oldp
= mem2chunk(oldmem
);
3384 oldsize
= chunksize(oldp
);
3386 checked_request2size(bytes
, nb
);
3389 if (chunk_is_mmapped(oldp
))
3394 newp
= mremap_chunk(oldp
, nb
);
3395 if(newp
) return chunk2mem(newp
);
3397 /* Note the extra SIZE_SZ overhead. */
3398 if(oldsize
- SIZE_SZ
>= nb
) return oldmem
; /* do nothing */
3399 /* Must alloc, copy, free. */
3400 newmem
= public_mALLOc(bytes
);
3401 if (newmem
== 0) return 0; /* propagate failure */
3402 MALLOC_COPY(newmem
, oldmem
, oldsize
- 2*SIZE_SZ
);
3408 ar_ptr
= arena_for_chunk(oldp
);
3410 if(!mutex_trylock(&ar_ptr
->mutex
))
3411 ++(ar_ptr
->stat_lock_direct
);
3413 (void)mutex_lock(&ar_ptr
->mutex
);
3414 ++(ar_ptr
->stat_lock_wait
);
3417 (void)mutex_lock(&ar_ptr
->mutex
);
3421 /* As in malloc(), remember this arena for the next allocation. */
3422 tsd_setspecific(arena_key
, (Void_t
*)ar_ptr
);
3425 newp
= _int_realloc(ar_ptr
, oldmem
, bytes
);
3427 (void)mutex_unlock(&ar_ptr
->mutex
);
3428 assert(!newp
|| chunk_is_mmapped(mem2chunk(newp
)) ||
3429 ar_ptr
== arena_for_chunk(mem2chunk(newp
)));
3434 public_mEMALIGn(size_t alignment
, size_t bytes
)
3439 __malloc_ptr_t (*hook
) __MALLOC_PMT ((size_t, size_t,
3440 __const __malloc_ptr_t
)) =
3443 return (*hook
)(alignment
, bytes
, RETURN_ADDRESS (0));
3445 /* If need less alignment than we give anyway, just relay to malloc */
3446 if (alignment
<= MALLOC_ALIGNMENT
) return public_mALLOc(bytes
);
3448 /* Otherwise, ensure that it is at least a minimum chunk size */
3449 if (alignment
< MINSIZE
) alignment
= MINSIZE
;
3451 arena_get(ar_ptr
, bytes
+ alignment
+ MINSIZE
);
3454 p
= _int_memalign(ar_ptr
, alignment
, bytes
);
3455 (void)mutex_unlock(&ar_ptr
->mutex
);
3457 /* Maybe the failure is due to running out of mmapped areas. */
3458 if(ar_ptr
!= &main_arena
) {
3459 (void)mutex_lock(&main_arena
.mutex
);
3460 p
= _int_memalign(&main_arena
, alignment
, bytes
);
3461 (void)mutex_unlock(&main_arena
.mutex
);
3464 /* ... or sbrk() has failed and there is still a chance to mmap() */
3465 ar_ptr
= arena_get2(ar_ptr
->next
? ar_ptr
: 0, bytes
);
3467 p
= _int_memalign(ar_ptr
, alignment
, bytes
);
3468 (void)mutex_unlock(&ar_ptr
->mutex
);
3473 assert(!p
|| chunk_is_mmapped(mem2chunk(p
)) ||
3474 ar_ptr
== arena_for_chunk(mem2chunk(p
)));
3477 strong_alias (public_mEMALIGn
, __memalign_internal
)
3480 public_vALLOc(size_t bytes
)
3485 if(__malloc_initialized
< 0)
3487 arena_get(ar_ptr
, bytes
+ mp_
.pagesize
+ MINSIZE
);
3490 p
= _int_valloc(ar_ptr
, bytes
);
3491 (void)mutex_unlock(&ar_ptr
->mutex
);
3496 public_pVALLOc(size_t bytes
)
3501 if(__malloc_initialized
< 0)
3503 arena_get(ar_ptr
, bytes
+ 2*mp_
.pagesize
+ MINSIZE
);
3504 p
= _int_pvalloc(ar_ptr
, bytes
);
3505 (void)mutex_unlock(&ar_ptr
->mutex
);
3510 public_cALLOc(size_t n
, size_t elem_size
)
3513 mchunkptr oldtop
, p
;
3514 INTERNAL_SIZE_T bytes
, sz
, csz
, oldtopsize
;
3516 unsigned long clearsize
;
3517 unsigned long nclears
;
3519 __malloc_ptr_t (*hook
) __MALLOC_PMT ((size_t, __const __malloc_ptr_t
)) =
3522 /* size_t is unsigned so the behavior on overflow is defined. */
3523 bytes
= n
* elem_size
;
3524 #define HALF_INTERNAL_SIZE_T \
3525 (((INTERNAL_SIZE_T) 1) << (8 * sizeof (INTERNAL_SIZE_T) / 2))
3526 if (__builtin_expect ((n
| elem_size
) >= HALF_INTERNAL_SIZE_T
, 0)) {
3527 if (elem_size
!= 0 && bytes
/ elem_size
!= n
) {
3528 MALLOC_FAILURE_ACTION
;
3535 mem
= (*hook
)(sz
, RETURN_ADDRESS (0));
3539 return memset(mem
, 0, sz
);
3541 while(sz
> 0) ((char*)mem
)[--sz
] = 0; /* rather inefficient */
3552 /* Check if we hand out the top chunk, in which case there may be no
3556 oldtopsize
= chunksize(top(av
));
3557 #if MORECORE_CLEARS < 2
3558 /* Only newly allocated memory is guaranteed to be cleared. */
3559 if (av
== &main_arena
&&
3560 oldtopsize
< mp_
.sbrk_base
+ av
->max_system_mem
- (char *)oldtop
)
3561 oldtopsize
= (mp_
.sbrk_base
+ av
->max_system_mem
- (char *)oldtop
);
3564 mem
= _int_malloc(av
, sz
);
3566 /* Only clearing follows, so we can unlock early. */
3567 (void)mutex_unlock(&av
->mutex
);
3569 assert(!mem
|| chunk_is_mmapped(mem2chunk(mem
)) ||
3570 av
== arena_for_chunk(mem2chunk(mem
)));
3573 /* Maybe the failure is due to running out of mmapped areas. */
3574 if(av
!= &main_arena
) {
3575 (void)mutex_lock(&main_arena
.mutex
);
3576 mem
= _int_malloc(&main_arena
, sz
);
3577 (void)mutex_unlock(&main_arena
.mutex
);
3580 /* ... or sbrk() has failed and there is still a chance to mmap() */
3581 (void)mutex_lock(&main_arena
.mutex
);
3582 av
= arena_get2(av
->next
? av
: 0, sz
);
3583 (void)mutex_unlock(&main_arena
.mutex
);
3585 mem
= _int_malloc(av
, sz
);
3586 (void)mutex_unlock(&av
->mutex
);
3590 if (mem
== 0) return 0;
3594 /* Two optional cases in which clearing not necessary */
3596 if (chunk_is_mmapped(p
))
3603 if (p
== oldtop
&& csz
> oldtopsize
) {
3604 /* clear only the bytes from non-freshly-sbrked memory */
3609 /* Unroll clear of <= 36 bytes (72 if 8byte sizes). We know that
3610 contents have an odd number of INTERNAL_SIZE_T-sized words;
3612 d
= (INTERNAL_SIZE_T
*)mem
;
3613 clearsize
= csz
- SIZE_SZ
;
3614 nclears
= clearsize
/ sizeof(INTERNAL_SIZE_T
);
3615 assert(nclears
>= 3);
3618 MALLOC_ZERO(d
, clearsize
);
3642 public_iCALLOc(size_t n
, size_t elem_size
, Void_t
** chunks
)
3647 arena_get(ar_ptr
, n
*elem_size
);
3651 m
= _int_icalloc(ar_ptr
, n
, elem_size
, chunks
);
3652 (void)mutex_unlock(&ar_ptr
->mutex
);
3657 public_iCOMALLOc(size_t n
, size_t sizes
[], Void_t
** chunks
)
3662 arena_get(ar_ptr
, 0);
3666 m
= _int_icomalloc(ar_ptr
, n
, sizes
, chunks
);
3667 (void)mutex_unlock(&ar_ptr
->mutex
);
3674 public_cFREe(Void_t
* m
)
3682 public_mTRIm(size_t s
)
3686 (void)mutex_lock(&main_arena
.mutex
);
3688 (void)mutex_unlock(&main_arena
.mutex
);
3693 public_mUSABLe(Void_t
* m
)
3697 result
= mUSABLe(m
);
3707 struct mallinfo
public_mALLINFo()
3711 (void)mutex_lock(&main_arena
.mutex
);
3712 m
= mALLINFo(&main_arena
);
3713 (void)mutex_unlock(&main_arena
.mutex
);
3718 public_mALLOPt(int p
, int v
)
3721 result
= mALLOPt(p
, v
);
3726 ------------------------------ malloc ------------------------------
3730 _int_malloc(mstate av
, size_t bytes
)
3732 INTERNAL_SIZE_T nb
; /* normalized request size */
3733 unsigned int idx
; /* associated bin index */
3734 mbinptr bin
; /* associated bin */
3735 mfastbinptr
* fb
; /* associated fastbin */
3737 mchunkptr victim
; /* inspected/selected chunk */
3738 INTERNAL_SIZE_T size
; /* its size */
3739 int victim_index
; /* its bin index */
3741 mchunkptr remainder
; /* remainder from a split */
3742 unsigned long remainder_size
; /* its size */
3744 unsigned int block
; /* bit map traverser */
3745 unsigned int bit
; /* bit map traverser */
3746 unsigned int map
; /* current word of binmap */
3748 mchunkptr fwd
; /* misc temp for linking */
3749 mchunkptr bck
; /* misc temp for linking */
3752 Convert request size to internal form by adding SIZE_SZ bytes
3753 overhead plus possibly more to obtain necessary alignment and/or
3754 to obtain a size of at least MINSIZE, the smallest allocatable
3755 size. Also, checked_request2size traps (returning 0) request sizes
3756 that are so large that they wrap around zero when padded and
3760 checked_request2size(bytes
, nb
);
3763 If the size qualifies as a fastbin, first check corresponding bin.
3764 This code is safe to execute even if av is not yet initialized, so we
3765 can try it without checking, which saves some time on this fast path.
3768 if ((unsigned long)(nb
) <= (unsigned long)(av
->max_fast
)) {
3769 fb
= &(av
->fastbins
[(fastbin_index(nb
))]);
3770 if ( (victim
= *fb
) != 0) {
3772 check_remalloced_chunk(av
, victim
, nb
);
3773 return chunk2mem(victim
);
3778 If a small request, check regular bin. Since these "smallbins"
3779 hold one size each, no searching within bins is necessary.
3780 (For a large request, we need to wait until unsorted chunks are
3781 processed to find best fit. But for small ones, fits are exact
3782 anyway, so we can check now, which is faster.)
3785 if (in_smallbin_range(nb
)) {
3786 idx
= smallbin_index(nb
);
3787 bin
= bin_at(av
,idx
);
3789 if ( (victim
= last(bin
)) != bin
) {
3790 if (victim
== 0) /* initialization check */
3791 malloc_consolidate(av
);
3794 set_inuse_bit_at_offset(victim
, nb
);
3798 if (av
!= &main_arena
)
3799 victim
->size
|= NON_MAIN_ARENA
;
3800 check_malloced_chunk(av
, victim
, nb
);
3801 return chunk2mem(victim
);
3807 If this is a large request, consolidate fastbins before continuing.
3808 While it might look excessive to kill all fastbins before
3809 even seeing if there is space available, this avoids
3810 fragmentation problems normally associated with fastbins.
3811 Also, in practice, programs tend to have runs of either small or
3812 large requests, but less often mixtures, so consolidation is not
3813 invoked all that often in most programs. And the programs that
3814 it is called frequently in otherwise tend to fragment.
3818 idx
= largebin_index(nb
);
3819 if (have_fastchunks(av
))
3820 malloc_consolidate(av
);
3824 Process recently freed or remaindered chunks, taking one only if
3825 it is exact fit, or, if this a small request, the chunk is remainder from
3826 the most recent non-exact fit. Place other traversed chunks in
3827 bins. Note that this step is the only place in any routine where
3828 chunks are placed in bins.
3830 The outer loop here is needed because we might not realize until
3831 near the end of malloc that we should have consolidated, so must
3832 do so and retry. This happens at most once, and only when we would
3833 otherwise need to expand memory to service a "small" request.
3838 while ( (victim
= unsorted_chunks(av
)->bk
) != unsorted_chunks(av
)) {
3840 size
= chunksize(victim
);
3843 If a small request, try to use last remainder if it is the
3844 only chunk in unsorted bin. This helps promote locality for
3845 runs of consecutive small requests. This is the only
3846 exception to best-fit, and applies only when there is
3847 no exact fit for a small chunk.
3850 if (in_smallbin_range(nb
) &&
3851 bck
== unsorted_chunks(av
) &&
3852 victim
== av
->last_remainder
&&
3853 (unsigned long)(size
) > (unsigned long)(nb
+ MINSIZE
)) {
3855 /* split and reattach remainder */
3856 remainder_size
= size
- nb
;
3857 remainder
= chunk_at_offset(victim
, nb
);
3858 unsorted_chunks(av
)->bk
= unsorted_chunks(av
)->fd
= remainder
;
3859 av
->last_remainder
= remainder
;
3860 remainder
->bk
= remainder
->fd
= unsorted_chunks(av
);
3862 set_head(victim
, nb
| PREV_INUSE
|
3863 (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
3864 set_head(remainder
, remainder_size
| PREV_INUSE
);
3865 set_foot(remainder
, remainder_size
);
3867 check_malloced_chunk(av
, victim
, nb
);
3868 return chunk2mem(victim
);
3871 /* remove from unsorted list */
3872 unsorted_chunks(av
)->bk
= bck
;
3873 bck
->fd
= unsorted_chunks(av
);
3875 /* Take now instead of binning if exact fit */
3878 set_inuse_bit_at_offset(victim
, size
);
3879 if (av
!= &main_arena
)
3880 victim
->size
|= NON_MAIN_ARENA
;
3881 check_malloced_chunk(av
, victim
, nb
);
3882 return chunk2mem(victim
);
3885 /* place chunk in bin */
3887 if (in_smallbin_range(size
)) {
3888 victim_index
= smallbin_index(size
);
3889 bck
= bin_at(av
, victim_index
);
3893 victim_index
= largebin_index(size
);
3894 bck
= bin_at(av
, victim_index
);
3897 /* maintain large bins in sorted order */
3899 /* Or with inuse bit to speed comparisons */
3901 /* if smaller than smallest, bypass loop below */
3902 assert((bck
->bk
->size
& NON_MAIN_ARENA
) == 0);
3903 if ((unsigned long)(size
) <= (unsigned long)(bck
->bk
->size
)) {
3908 assert((fwd
->size
& NON_MAIN_ARENA
) == 0);
3909 while ((unsigned long)(size
) < (unsigned long)(fwd
->size
)) {
3911 assert((fwd
->size
& NON_MAIN_ARENA
) == 0);
3918 mark_bin(av
, victim_index
);
3926 If a large request, scan through the chunks of current bin in
3927 sorted order to find smallest that fits. This is the only step
3928 where an unbounded number of chunks might be scanned without doing
3929 anything useful with them. However the lists tend to be short.
3932 if (!in_smallbin_range(nb
)) {
3933 bin
= bin_at(av
, idx
);
3935 /* skip scan if empty or largest chunk is too small */
3936 if ((victim
= last(bin
)) != bin
&&
3937 (unsigned long)(first(bin
)->size
) >= (unsigned long)(nb
)) {
3939 while (((unsigned long)(size
= chunksize(victim
)) <
3940 (unsigned long)(nb
)))
3941 victim
= victim
->bk
;
3943 remainder_size
= size
- nb
;
3944 unlink(victim
, bck
, fwd
);
3947 if (remainder_size
< MINSIZE
) {
3948 set_inuse_bit_at_offset(victim
, size
);
3949 if (av
!= &main_arena
)
3950 victim
->size
|= NON_MAIN_ARENA
;
3951 check_malloced_chunk(av
, victim
, nb
);
3952 return chunk2mem(victim
);
3956 remainder
= chunk_at_offset(victim
, nb
);
3957 unsorted_chunks(av
)->bk
= unsorted_chunks(av
)->fd
= remainder
;
3958 remainder
->bk
= remainder
->fd
= unsorted_chunks(av
);
3959 set_head(victim
, nb
| PREV_INUSE
|
3960 (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
3961 set_head(remainder
, remainder_size
| PREV_INUSE
);
3962 set_foot(remainder
, remainder_size
);
3963 check_malloced_chunk(av
, victim
, nb
);
3964 return chunk2mem(victim
);
3970 Search for a chunk by scanning bins, starting with next largest
3971 bin. This search is strictly by best-fit; i.e., the smallest
3972 (with ties going to approximately the least recently used) chunk
3973 that fits is selected.
3975 The bitmap avoids needing to check that most blocks are nonempty.
3976 The particular case of skipping all bins during warm-up phases
3977 when no chunks have been returned yet is faster than it might look.
3981 bin
= bin_at(av
,idx
);
3982 block
= idx2block(idx
);
3983 map
= av
->binmap
[block
];
3988 /* Skip rest of block if there are no more set bits in this block. */
3989 if (bit
> map
|| bit
== 0) {
3991 if (++block
>= BINMAPSIZE
) /* out of bins */
3993 } while ( (map
= av
->binmap
[block
]) == 0);
3995 bin
= bin_at(av
, (block
<< BINMAPSHIFT
));
3999 /* Advance to bin with set bit. There must be one. */
4000 while ((bit
& map
) == 0) {
4001 bin
= next_bin(bin
);
4006 /* Inspect the bin. It is likely to be non-empty */
4009 /* If a false alarm (empty bin), clear the bit. */
4010 if (victim
== bin
) {
4011 av
->binmap
[block
] = map
&= ~bit
; /* Write through */
4012 bin
= next_bin(bin
);
4017 size
= chunksize(victim
);
4019 /* We know the first chunk in this bin is big enough to use. */
4020 assert((unsigned long)(size
) >= (unsigned long)(nb
));
4022 remainder_size
= size
- nb
;
4030 if (remainder_size
< MINSIZE
) {
4031 set_inuse_bit_at_offset(victim
, size
);
4032 if (av
!= &main_arena
)
4033 victim
->size
|= NON_MAIN_ARENA
;
4034 check_malloced_chunk(av
, victim
, nb
);
4035 return chunk2mem(victim
);
4040 remainder
= chunk_at_offset(victim
, nb
);
4042 unsorted_chunks(av
)->bk
= unsorted_chunks(av
)->fd
= remainder
;
4043 remainder
->bk
= remainder
->fd
= unsorted_chunks(av
);
4044 /* advertise as last remainder */
4045 if (in_smallbin_range(nb
))
4046 av
->last_remainder
= remainder
;
4048 set_head(victim
, nb
| PREV_INUSE
|
4049 (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4050 set_head(remainder
, remainder_size
| PREV_INUSE
);
4051 set_foot(remainder
, remainder_size
);
4052 check_malloced_chunk(av
, victim
, nb
);
4053 return chunk2mem(victim
);
4060 If large enough, split off the chunk bordering the end of memory
4061 (held in av->top). Note that this is in accord with the best-fit
4062 search rule. In effect, av->top is treated as larger (and thus
4063 less well fitting) than any other available chunk since it can
4064 be extended to be as large as necessary (up to system
4067 We require that av->top always exists (i.e., has size >=
4068 MINSIZE) after initialization, so if it would otherwise be
4069 exhuasted by current request, it is replenished. (The main
4070 reason for ensuring it exists is that we may need MINSIZE space
4071 to put in fenceposts in sysmalloc.)
4075 size
= chunksize(victim
);
4077 if ((unsigned long)(size
) >= (unsigned long)(nb
+ MINSIZE
)) {
4078 remainder_size
= size
- nb
;
4079 remainder
= chunk_at_offset(victim
, nb
);
4080 av
->top
= remainder
;
4081 set_head(victim
, nb
| PREV_INUSE
|
4082 (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4083 set_head(remainder
, remainder_size
| PREV_INUSE
);
4085 check_malloced_chunk(av
, victim
, nb
);
4086 return chunk2mem(victim
);
4090 If there is space available in fastbins, consolidate and retry,
4091 to possibly avoid expanding memory. This can occur only if nb is
4092 in smallbin range so we didn't consolidate upon entry.
4095 else if (have_fastchunks(av
)) {
4096 assert(in_smallbin_range(nb
));
4097 malloc_consolidate(av
);
4098 idx
= smallbin_index(nb
); /* restore original bin index */
4102 Otherwise, relay to handle system-dependent cases
4105 return sYSMALLOc(nb
, av
);
4110 ------------------------------ free ------------------------------
4114 _int_free(mstate av
, Void_t
* mem
)
4116 mchunkptr p
; /* chunk corresponding to mem */
4117 INTERNAL_SIZE_T size
; /* its size */
4118 mfastbinptr
* fb
; /* associated fastbin */
4119 mchunkptr nextchunk
; /* next contiguous chunk */
4120 INTERNAL_SIZE_T nextsize
; /* its size */
4121 int nextinuse
; /* true if nextchunk is used */
4122 INTERNAL_SIZE_T prevsize
; /* size of previous contiguous chunk */
4123 mchunkptr bck
; /* misc temp for linking */
4124 mchunkptr fwd
; /* misc temp for linking */
4127 /* free(0) has no effect */
4130 size
= chunksize(p
);
4132 check_inuse_chunk(av
, p
);
4135 If eligible, place chunk on a fastbin so it can be found
4136 and used quickly in malloc.
4139 if ((unsigned long)(size
) <= (unsigned long)(av
->max_fast
)
4143 If TRIM_FASTBINS set, don't place chunks
4144 bordering top into fastbins
4146 && (chunk_at_offset(p
, size
) != av
->top
)
4151 fb
= &(av
->fastbins
[fastbin_index(size
)]);
4157 Consolidate other non-mmapped chunks as they arrive.
4160 else if (!chunk_is_mmapped(p
)) {
4161 nextchunk
= chunk_at_offset(p
, size
);
4162 nextsize
= chunksize(nextchunk
);
4163 assert(nextsize
> 0);
4165 /* consolidate backward */
4166 if (!prev_inuse(p
)) {
4167 prevsize
= p
->prev_size
;
4169 p
= chunk_at_offset(p
, -((long) prevsize
));
4170 unlink(p
, bck
, fwd
);
4173 if (nextchunk
!= av
->top
) {
4174 /* get and clear inuse bit */
4175 nextinuse
= inuse_bit_at_offset(nextchunk
, nextsize
);
4177 /* consolidate forward */
4179 unlink(nextchunk
, bck
, fwd
);
4182 clear_inuse_bit_at_offset(nextchunk
, 0);
4185 Place the chunk in unsorted chunk list. Chunks are
4186 not placed into regular bins until after they have
4187 been given one chance to be used in malloc.
4190 bck
= unsorted_chunks(av
);
4197 set_head(p
, size
| PREV_INUSE
);
4200 check_free_chunk(av
, p
);
4204 If the chunk borders the current high end of memory,
4205 consolidate into top
4210 set_head(p
, size
| PREV_INUSE
);
4216 If freeing a large space, consolidate possibly-surrounding
4217 chunks. Then, if the total unused topmost memory exceeds trim
4218 threshold, ask malloc_trim to reduce top.
4220 Unless max_fast is 0, we don't know if there are fastbins
4221 bordering top, so we cannot tell for sure whether threshold
4222 has been reached unless fastbins are consolidated. But we
4223 don't want to consolidate on each free. As a compromise,
4224 consolidation is performed if FASTBIN_CONSOLIDATION_THRESHOLD
4228 if ((unsigned long)(size
) >= FASTBIN_CONSOLIDATION_THRESHOLD
) {
4229 if (have_fastchunks(av
))
4230 malloc_consolidate(av
);
4232 if (av
== &main_arena
) {
4233 #ifndef MORECORE_CANNOT_TRIM
4234 if ((unsigned long)(chunksize(av
->top
)) >=
4235 (unsigned long)(mp_
.trim_threshold
))
4236 sYSTRIm(mp_
.top_pad
, av
);
4239 /* Always try heap_trim(), even if the top chunk is not
4240 large, because the corresponding heap might go away. */
4241 heap_info
*heap
= heap_for_ptr(top(av
));
4243 assert(heap
->ar_ptr
== av
);
4244 heap_trim(heap
, mp_
.top_pad
);
4250 If the chunk was allocated via mmap, release via munmap(). Note
4251 that if HAVE_MMAP is false but chunk_is_mmapped is true, then
4252 user must have overwritten memory. There's nothing we can do to
4253 catch this error unless MALLOC_DEBUG is set, in which case
4254 check_inuse_chunk (above) will have triggered error.
4260 INTERNAL_SIZE_T offset
= p
->prev_size
;
4262 mp_
.mmapped_mem
-= (size
+ offset
);
4263 ret
= munmap((char*)p
- offset
, size
+ offset
);
4264 /* munmap returns non-zero on failure */
4272 ------------------------- malloc_consolidate -------------------------
4274 malloc_consolidate is a specialized version of free() that tears
4275 down chunks held in fastbins. Free itself cannot be used for this
4276 purpose since, among other things, it might place chunks back onto
4277 fastbins. So, instead, we need to use a minor variant of the same
4280 Also, because this routine needs to be called the first time through
4281 malloc anyway, it turns out to be the perfect place to trigger
4282 initialization code.
4286 static void malloc_consolidate(mstate av
)
4288 static void malloc_consolidate(av
) mstate av
;
4291 mfastbinptr
* fb
; /* current fastbin being consolidated */
4292 mfastbinptr
* maxfb
; /* last fastbin (for loop control) */
4293 mchunkptr p
; /* current chunk being consolidated */
4294 mchunkptr nextp
; /* next chunk to consolidate */
4295 mchunkptr unsorted_bin
; /* bin header */
4296 mchunkptr first_unsorted
; /* chunk to link to */
4298 /* These have same use as in free() */
4299 mchunkptr nextchunk
;
4300 INTERNAL_SIZE_T size
;
4301 INTERNAL_SIZE_T nextsize
;
4302 INTERNAL_SIZE_T prevsize
;
4308 If max_fast is 0, we know that av hasn't
4309 yet been initialized, in which case do so below
4312 if (av
->max_fast
!= 0) {
4313 clear_fastchunks(av
);
4315 unsorted_bin
= unsorted_chunks(av
);
4318 Remove each chunk from fast bin and consolidate it, placing it
4319 then in unsorted bin. Among other reasons for doing this,
4320 placing in unsorted bin avoids needing to calculate actual bins
4321 until malloc is sure that chunks aren't immediately going to be
4325 maxfb
= &(av
->fastbins
[fastbin_index(av
->max_fast
)]);
4326 fb
= &(av
->fastbins
[0]);
4328 if ( (p
= *fb
) != 0) {
4332 check_inuse_chunk(av
, p
);
4335 /* Slightly streamlined version of consolidation code in free() */
4336 size
= p
->size
& ~(PREV_INUSE
|NON_MAIN_ARENA
);
4337 nextchunk
= chunk_at_offset(p
, size
);
4338 nextsize
= chunksize(nextchunk
);
4340 if (!prev_inuse(p
)) {
4341 prevsize
= p
->prev_size
;
4343 p
= chunk_at_offset(p
, -((long) prevsize
));
4344 unlink(p
, bck
, fwd
);
4347 if (nextchunk
!= av
->top
) {
4348 nextinuse
= inuse_bit_at_offset(nextchunk
, nextsize
);
4352 unlink(nextchunk
, bck
, fwd
);
4354 clear_inuse_bit_at_offset(nextchunk
, 0);
4356 first_unsorted
= unsorted_bin
->fd
;
4357 unsorted_bin
->fd
= p
;
4358 first_unsorted
->bk
= p
;
4360 set_head(p
, size
| PREV_INUSE
);
4361 p
->bk
= unsorted_bin
;
4362 p
->fd
= first_unsorted
;
4368 set_head(p
, size
| PREV_INUSE
);
4372 } while ( (p
= nextp
) != 0);
4375 } while (fb
++ != maxfb
);
4378 malloc_init_state(av
);
4379 check_malloc_state(av
);
4384 ------------------------------ realloc ------------------------------
4388 _int_realloc(mstate av
, Void_t
* oldmem
, size_t bytes
)
4390 INTERNAL_SIZE_T nb
; /* padded request size */
4392 mchunkptr oldp
; /* chunk corresponding to oldmem */
4393 INTERNAL_SIZE_T oldsize
; /* its size */
4395 mchunkptr newp
; /* chunk to return */
4396 INTERNAL_SIZE_T newsize
; /* its size */
4397 Void_t
* newmem
; /* corresponding user mem */
4399 mchunkptr next
; /* next contiguous chunk after oldp */
4401 mchunkptr remainder
; /* extra space at end of newp */
4402 unsigned long remainder_size
; /* its size */
4404 mchunkptr bck
; /* misc temp for linking */
4405 mchunkptr fwd
; /* misc temp for linking */
4407 unsigned long copysize
; /* bytes to copy */
4408 unsigned int ncopies
; /* INTERNAL_SIZE_T words to copy */
4409 INTERNAL_SIZE_T
* s
; /* copy source */
4410 INTERNAL_SIZE_T
* d
; /* copy destination */
4413 #if REALLOC_ZERO_BYTES_FREES
4415 _int_free(av
, oldmem
);
4420 /* realloc of null is supposed to be same as malloc */
4421 if (oldmem
== 0) return _int_malloc(av
, bytes
);
4423 checked_request2size(bytes
, nb
);
4425 oldp
= mem2chunk(oldmem
);
4426 oldsize
= chunksize(oldp
);
4428 check_inuse_chunk(av
, oldp
);
4430 if (!chunk_is_mmapped(oldp
)) {
4432 if ((unsigned long)(oldsize
) >= (unsigned long)(nb
)) {
4433 /* already big enough; split below */
4439 next
= chunk_at_offset(oldp
, oldsize
);
4441 /* Try to expand forward into top */
4442 if (next
== av
->top
&&
4443 (unsigned long)(newsize
= oldsize
+ chunksize(next
)) >=
4444 (unsigned long)(nb
+ MINSIZE
)) {
4445 set_head_size(oldp
, nb
| (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4446 av
->top
= chunk_at_offset(oldp
, nb
);
4447 set_head(av
->top
, (newsize
- nb
) | PREV_INUSE
);
4448 check_inuse_chunk(av
, oldp
);
4449 return chunk2mem(oldp
);
4452 /* Try to expand forward into next chunk; split off remainder below */
4453 else if (next
!= av
->top
&&
4455 (unsigned long)(newsize
= oldsize
+ chunksize(next
)) >=
4456 (unsigned long)(nb
)) {
4458 unlink(next
, bck
, fwd
);
4461 /* allocate, copy, free */
4463 newmem
= _int_malloc(av
, nb
- MALLOC_ALIGN_MASK
);
4465 return 0; /* propagate failure */
4467 newp
= mem2chunk(newmem
);
4468 newsize
= chunksize(newp
);
4471 Avoid copy if newp is next chunk after oldp.
4479 Unroll copy of <= 36 bytes (72 if 8byte sizes)
4480 We know that contents have an odd number of
4481 INTERNAL_SIZE_T-sized words; minimally 3.
4484 copysize
= oldsize
- SIZE_SZ
;
4485 s
= (INTERNAL_SIZE_T
*)(oldmem
);
4486 d
= (INTERNAL_SIZE_T
*)(newmem
);
4487 ncopies
= copysize
/ sizeof(INTERNAL_SIZE_T
);
4488 assert(ncopies
>= 3);
4491 MALLOC_COPY(d
, s
, copysize
);
4511 _int_free(av
, oldmem
);
4512 check_inuse_chunk(av
, newp
);
4513 return chunk2mem(newp
);
4518 /* If possible, free extra space in old or extended chunk */
4520 assert((unsigned long)(newsize
) >= (unsigned long)(nb
));
4522 remainder_size
= newsize
- nb
;
4524 if (remainder_size
< MINSIZE
) { /* not enough extra to split off */
4525 set_head_size(newp
, newsize
| (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4526 set_inuse_bit_at_offset(newp
, newsize
);
4528 else { /* split remainder */
4529 remainder
= chunk_at_offset(newp
, nb
);
4530 set_head_size(newp
, nb
| (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4531 set_head(remainder
, remainder_size
| PREV_INUSE
|
4532 (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4533 /* Mark remainder as inuse so free() won't complain */
4534 set_inuse_bit_at_offset(remainder
, remainder_size
);
4535 _int_free(av
, chunk2mem(remainder
));
4538 check_inuse_chunk(av
, newp
);
4539 return chunk2mem(newp
);
4550 INTERNAL_SIZE_T offset
= oldp
->prev_size
;
4551 size_t pagemask
= mp_
.pagesize
- 1;
4555 /* Note the extra SIZE_SZ overhead */
4556 newsize
= (nb
+ offset
+ SIZE_SZ
+ pagemask
) & ~pagemask
;
4558 /* don't need to remap if still within same page */
4559 if (oldsize
== newsize
- offset
)
4562 cp
= (char*)mremap((char*)oldp
- offset
, oldsize
+ offset
, newsize
, 1);
4564 if (cp
!= MAP_FAILED
) {
4566 newp
= (mchunkptr
)(cp
+ offset
);
4567 set_head(newp
, (newsize
- offset
)|IS_MMAPPED
);
4569 assert(aligned_OK(chunk2mem(newp
)));
4570 assert((newp
->prev_size
== offset
));
4572 /* update statistics */
4573 sum
= mp_
.mmapped_mem
+= newsize
- oldsize
;
4574 if (sum
> (unsigned long)(mp_
.max_mmapped_mem
))
4575 mp_
.max_mmapped_mem
= sum
;
4577 sum
+= main_arena
.system_mem
;
4578 if (sum
> (unsigned long)(mp_
.max_total_mem
))
4579 mp_
.max_total_mem
= sum
;
4582 return chunk2mem(newp
);
4586 /* Note the extra SIZE_SZ overhead. */
4587 if ((unsigned long)(oldsize
) >= (unsigned long)(nb
+ SIZE_SZ
))
4588 newmem
= oldmem
; /* do nothing */
4590 /* Must alloc, copy, free. */
4591 newmem
= _int_malloc(av
, nb
- MALLOC_ALIGN_MASK
);
4593 MALLOC_COPY(newmem
, oldmem
, oldsize
- 2*SIZE_SZ
);
4594 _int_free(av
, oldmem
);
4600 /* If !HAVE_MMAP, but chunk_is_mmapped, user must have overwritten mem */
4601 check_malloc_state(av
);
4602 MALLOC_FAILURE_ACTION
;
4609 ------------------------------ memalign ------------------------------
4613 _int_memalign(mstate av
, size_t alignment
, size_t bytes
)
4615 INTERNAL_SIZE_T nb
; /* padded request size */
4616 char* m
; /* memory returned by malloc call */
4617 mchunkptr p
; /* corresponding chunk */
4618 char* brk
; /* alignment point within p */
4619 mchunkptr newp
; /* chunk to return */
4620 INTERNAL_SIZE_T newsize
; /* its size */
4621 INTERNAL_SIZE_T leadsize
; /* leading space before alignment point */
4622 mchunkptr remainder
; /* spare room at end to split off */
4623 unsigned long remainder_size
; /* its size */
4624 INTERNAL_SIZE_T size
;
4626 /* If need less alignment than we give anyway, just relay to malloc */
4628 if (alignment
<= MALLOC_ALIGNMENT
) return _int_malloc(av
, bytes
);
4630 /* Otherwise, ensure that it is at least a minimum chunk size */
4632 if (alignment
< MINSIZE
) alignment
= MINSIZE
;
4634 /* Make sure alignment is power of 2 (in case MINSIZE is not). */
4635 if ((alignment
& (alignment
- 1)) != 0) {
4636 size_t a
= MALLOC_ALIGNMENT
* 2;
4637 while ((unsigned long)a
< (unsigned long)alignment
) a
<<= 1;
4641 checked_request2size(bytes
, nb
);
4644 Strategy: find a spot within that chunk that meets the alignment
4645 request, and then possibly free the leading and trailing space.
4649 /* Call malloc with worst case padding to hit alignment. */
4651 m
= (char*)(_int_malloc(av
, nb
+ alignment
+ MINSIZE
));
4653 if (m
== 0) return 0; /* propagate failure */
4657 if ((((unsigned long)(m
)) % alignment
) != 0) { /* misaligned */
4660 Find an aligned spot inside chunk. Since we need to give back
4661 leading space in a chunk of at least MINSIZE, if the first
4662 calculation places us at a spot with less than MINSIZE leader,
4663 we can move to the next aligned spot -- we've allocated enough
4664 total room so that this is always possible.
4667 brk
= (char*)mem2chunk(((unsigned long)(m
+ alignment
- 1)) &
4668 -((signed long) alignment
));
4669 if ((unsigned long)(brk
- (char*)(p
)) < MINSIZE
)
4672 newp
= (mchunkptr
)brk
;
4673 leadsize
= brk
- (char*)(p
);
4674 newsize
= chunksize(p
) - leadsize
;
4676 /* For mmapped chunks, just adjust offset */
4677 if (chunk_is_mmapped(p
)) {
4678 newp
->prev_size
= p
->prev_size
+ leadsize
;
4679 set_head(newp
, newsize
|IS_MMAPPED
);
4680 return chunk2mem(newp
);
4683 /* Otherwise, give back leader, use the rest */
4684 set_head(newp
, newsize
| PREV_INUSE
|
4685 (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4686 set_inuse_bit_at_offset(newp
, newsize
);
4687 set_head_size(p
, leadsize
| (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4688 _int_free(av
, chunk2mem(p
));
4691 assert (newsize
>= nb
&&
4692 (((unsigned long)(chunk2mem(p
))) % alignment
) == 0);
4695 /* Also give back spare room at the end */
4696 if (!chunk_is_mmapped(p
)) {
4697 size
= chunksize(p
);
4698 if ((unsigned long)(size
) > (unsigned long)(nb
+ MINSIZE
)) {
4699 remainder_size
= size
- nb
;
4700 remainder
= chunk_at_offset(p
, nb
);
4701 set_head(remainder
, remainder_size
| PREV_INUSE
|
4702 (av
!= &main_arena
? NON_MAIN_ARENA
: 0));
4703 set_head_size(p
, nb
);
4704 _int_free(av
, chunk2mem(remainder
));
4708 check_inuse_chunk(av
, p
);
4709 return chunk2mem(p
);
4714 ------------------------------ calloc ------------------------------
4718 Void_t
* cALLOc(size_t n_elements
, size_t elem_size
)
4720 Void_t
* cALLOc(n_elements
, elem_size
) size_t n_elements
; size_t elem_size
;
4724 unsigned long clearsize
;
4725 unsigned long nclears
;
4728 Void_t
* mem
= mALLOc(n_elements
* elem_size
);
4734 if (!chunk_is_mmapped(p
)) /* don't need to clear mmapped space */
4738 Unroll clear of <= 36 bytes (72 if 8byte sizes)
4739 We know that contents have an odd number of
4740 INTERNAL_SIZE_T-sized words; minimally 3.
4743 d
= (INTERNAL_SIZE_T
*)mem
;
4744 clearsize
= chunksize(p
) - SIZE_SZ
;
4745 nclears
= clearsize
/ sizeof(INTERNAL_SIZE_T
);
4746 assert(nclears
>= 3);
4749 MALLOC_ZERO(d
, clearsize
);
4775 ------------------------- independent_calloc -------------------------
4780 _int_icalloc(mstate av
, size_t n_elements
, size_t elem_size
, Void_t
* chunks
[])
4782 _int_icalloc(av
, n_elements
, elem_size
, chunks
)
4783 mstate av
; size_t n_elements
; size_t elem_size
; Void_t
* chunks
[];
4786 size_t sz
= elem_size
; /* serves as 1-element array */
4787 /* opts arg of 3 means all elements are same size, and should be cleared */
4788 return iALLOc(av
, n_elements
, &sz
, 3, chunks
);
4792 ------------------------- independent_comalloc -------------------------
4797 _int_icomalloc(mstate av
, size_t n_elements
, size_t sizes
[], Void_t
* chunks
[])
4799 _int_icomalloc(av
, n_elements
, sizes
, chunks
)
4800 mstate av
; size_t n_elements
; size_t sizes
[]; Void_t
* chunks
[];
4803 return iALLOc(av
, n_elements
, sizes
, 0, chunks
);
4808 ------------------------------ ialloc ------------------------------
4809 ialloc provides common support for independent_X routines, handling all of
4810 the combinations that can result.
4813 bit 0 set if all elements are same size (using sizes[0])
4814 bit 1 set if elements should be zeroed
4820 iALLOc(mstate av
, size_t n_elements
, size_t* sizes
, int opts
, Void_t
* chunks
[])
4822 iALLOc(av
, n_elements
, sizes
, opts
, chunks
)
4823 mstate av
; size_t n_elements
; size_t* sizes
; int opts
; Void_t
* chunks
[];
4826 INTERNAL_SIZE_T element_size
; /* chunksize of each element, if all same */
4827 INTERNAL_SIZE_T contents_size
; /* total size of elements */
4828 INTERNAL_SIZE_T array_size
; /* request size of pointer array */
4829 Void_t
* mem
; /* malloced aggregate space */
4830 mchunkptr p
; /* corresponding chunk */
4831 INTERNAL_SIZE_T remainder_size
; /* remaining bytes while splitting */
4832 Void_t
** marray
; /* either "chunks" or malloced ptr array */
4833 mchunkptr array_chunk
; /* chunk for malloced ptr array */
4834 int mmx
; /* to disable mmap */
4835 INTERNAL_SIZE_T size
;
4836 INTERNAL_SIZE_T size_flags
;
4839 /* Ensure initialization/consolidation */
4840 if (have_fastchunks(av
)) malloc_consolidate(av
);
4842 /* compute array length, if needed */
4844 if (n_elements
== 0)
4845 return chunks
; /* nothing to do */
4850 /* if empty req, must still return chunk representing empty array */
4851 if (n_elements
== 0)
4852 return (Void_t
**) _int_malloc(av
, 0);
4854 array_size
= request2size(n_elements
* (sizeof(Void_t
*)));
4857 /* compute total element size */
4858 if (opts
& 0x1) { /* all-same-size */
4859 element_size
= request2size(*sizes
);
4860 contents_size
= n_elements
* element_size
;
4862 else { /* add up all the sizes */
4865 for (i
= 0; i
!= n_elements
; ++i
)
4866 contents_size
+= request2size(sizes
[i
]);
4869 /* subtract out alignment bytes from total to minimize overallocation */
4870 size
= contents_size
+ array_size
- MALLOC_ALIGN_MASK
;
4873 Allocate the aggregate chunk.
4874 But first disable mmap so malloc won't use it, since
4875 we would not be able to later free/realloc space internal
4876 to a segregated mmap region.
4878 mmx
= mp_
.n_mmaps_max
; /* disable mmap */
4879 mp_
.n_mmaps_max
= 0;
4880 mem
= _int_malloc(av
, size
);
4881 mp_
.n_mmaps_max
= mmx
; /* reset mmap */
4886 assert(!chunk_is_mmapped(p
));
4887 remainder_size
= chunksize(p
);
4889 if (opts
& 0x2) { /* optionally clear the elements */
4890 MALLOC_ZERO(mem
, remainder_size
- SIZE_SZ
- array_size
);
4893 size_flags
= PREV_INUSE
| (av
!= &main_arena
? NON_MAIN_ARENA
: 0);
4895 /* If not provided, allocate the pointer array as final part of chunk */
4897 array_chunk
= chunk_at_offset(p
, contents_size
);
4898 marray
= (Void_t
**) (chunk2mem(array_chunk
));
4899 set_head(array_chunk
, (remainder_size
- contents_size
) | size_flags
);
4900 remainder_size
= contents_size
;
4903 /* split out elements */
4904 for (i
= 0; ; ++i
) {
4905 marray
[i
] = chunk2mem(p
);
4906 if (i
!= n_elements
-1) {
4907 if (element_size
!= 0)
4908 size
= element_size
;
4910 size
= request2size(sizes
[i
]);
4911 remainder_size
-= size
;
4912 set_head(p
, size
| size_flags
);
4913 p
= chunk_at_offset(p
, size
);
4915 else { /* the final element absorbs any overallocation slop */
4916 set_head(p
, remainder_size
| size_flags
);
4922 if (marray
!= chunks
) {
4923 /* final element must have exactly exhausted chunk */
4924 if (element_size
!= 0)
4925 assert(remainder_size
== element_size
);
4927 assert(remainder_size
== request2size(sizes
[i
]));
4928 check_inuse_chunk(av
, mem2chunk(marray
));
4931 for (i
= 0; i
!= n_elements
; ++i
)
4932 check_inuse_chunk(av
, mem2chunk(marray
[i
]));
4940 ------------------------------ valloc ------------------------------
4945 _int_valloc(mstate av
, size_t bytes
)
4947 _int_valloc(av
, bytes
) mstate av
; size_t bytes
;
4950 /* Ensure initialization/consolidation */
4951 if (have_fastchunks(av
)) malloc_consolidate(av
);
4952 return _int_memalign(av
, mp_
.pagesize
, bytes
);
4956 ------------------------------ pvalloc ------------------------------
4962 _int_pvalloc(mstate av
, size_t bytes
)
4964 _int_pvalloc(av
, bytes
) mstate av
, size_t bytes
;
4969 /* Ensure initialization/consolidation */
4970 if (have_fastchunks(av
)) malloc_consolidate(av
);
4971 pagesz
= mp_
.pagesize
;
4972 return _int_memalign(av
, pagesz
, (bytes
+ pagesz
- 1) & ~(pagesz
- 1));
4977 ------------------------------ malloc_trim ------------------------------
4981 int mTRIm(size_t pad
)
4983 int mTRIm(pad
) size_t pad
;
4986 mstate av
= &main_arena
; /* already locked */
4988 /* Ensure initialization/consolidation */
4989 malloc_consolidate(av
);
4991 #ifndef MORECORE_CANNOT_TRIM
4992 return sYSTRIm(pad
, av
);
5000 ------------------------- malloc_usable_size -------------------------
5004 size_t mUSABLe(Void_t
* mem
)
5006 size_t mUSABLe(mem
) Void_t
* mem
;
5012 if (chunk_is_mmapped(p
))
5013 return chunksize(p
) - 2*SIZE_SZ
;
5015 return chunksize(p
) - SIZE_SZ
;
5021 ------------------------------ mallinfo ------------------------------
5024 struct mallinfo
mALLINFo(mstate av
)
5030 INTERNAL_SIZE_T avail
;
5031 INTERNAL_SIZE_T fastavail
;
5035 /* Ensure initialization */
5036 if (av
->top
== 0) malloc_consolidate(av
);
5038 check_malloc_state(av
);
5040 /* Account for top */
5041 avail
= chunksize(av
->top
);
5042 nblocks
= 1; /* top always exists */
5044 /* traverse fastbins */
5048 for (i
= 0; i
< NFASTBINS
; ++i
) {
5049 for (p
= av
->fastbins
[i
]; p
!= 0; p
= p
->fd
) {
5051 fastavail
+= chunksize(p
);
5057 /* traverse regular bins */
5058 for (i
= 1; i
< NBINS
; ++i
) {
5060 for (p
= last(b
); p
!= b
; p
= p
->bk
) {
5062 avail
+= chunksize(p
);
5066 mi
.smblks
= nfastblocks
;
5067 mi
.ordblks
= nblocks
;
5068 mi
.fordblks
= avail
;
5069 mi
.uordblks
= av
->system_mem
- avail
;
5070 mi
.arena
= av
->system_mem
;
5071 mi
.hblks
= mp_
.n_mmaps
;
5072 mi
.hblkhd
= mp_
.mmapped_mem
;
5073 mi
.fsmblks
= fastavail
;
5074 mi
.keepcost
= chunksize(av
->top
);
5075 mi
.usmblks
= mp_
.max_total_mem
;
5080 ------------------------------ malloc_stats ------------------------------
5088 unsigned int in_use_b
= mp_
.mmapped_mem
, system_b
= in_use_b
;
5090 long stat_lock_direct
= 0, stat_lock_loop
= 0, stat_lock_wait
= 0;
5093 if(__malloc_initialized
< 0)
5095 for (i
=0, ar_ptr
= &main_arena
;; i
++) {
5096 (void)mutex_lock(&ar_ptr
->mutex
);
5097 mi
= mALLINFo(ar_ptr
);
5098 fprintf(stderr
, "Arena %d:\n", i
);
5099 fprintf(stderr
, "system bytes = %10u\n", (unsigned int)mi
.arena
);
5100 fprintf(stderr
, "in use bytes = %10u\n", (unsigned int)mi
.uordblks
);
5101 #if MALLOC_DEBUG > 1
5103 dump_heap(heap_for_ptr(top(ar_ptr
)));
5105 system_b
+= mi
.arena
;
5106 in_use_b
+= mi
.uordblks
;
5108 stat_lock_direct
+= ar_ptr
->stat_lock_direct
;
5109 stat_lock_loop
+= ar_ptr
->stat_lock_loop
;
5110 stat_lock_wait
+= ar_ptr
->stat_lock_wait
;
5112 (void)mutex_unlock(&ar_ptr
->mutex
);
5113 ar_ptr
= ar_ptr
->next
;
5114 if(ar_ptr
== &main_arena
) break;
5117 fprintf(stderr
, "Total (incl. mmap):\n");
5119 fprintf(stderr
, "Total:\n");
5121 fprintf(stderr
, "system bytes = %10u\n", system_b
);
5122 fprintf(stderr
, "in use bytes = %10u\n", in_use_b
);
5124 fprintf(stderr
, "max system bytes = %10u\n", (unsigned int)mp_
.max_total_mem
);
5127 fprintf(stderr
, "max mmap regions = %10u\n", (unsigned int)mp_
.max_n_mmaps
);
5128 fprintf(stderr
, "max mmap bytes = %10lu\n",
5129 (unsigned long)mp_
.max_mmapped_mem
);
5132 fprintf(stderr
, "heaps created = %10d\n", stat_n_heaps
);
5133 fprintf(stderr
, "locked directly = %10ld\n", stat_lock_direct
);
5134 fprintf(stderr
, "locked in loop = %10ld\n", stat_lock_loop
);
5135 fprintf(stderr
, "locked waiting = %10ld\n", stat_lock_wait
);
5136 fprintf(stderr
, "locked total = %10ld\n",
5137 stat_lock_direct
+ stat_lock_loop
+ stat_lock_wait
);
5143 ------------------------------ mallopt ------------------------------
5147 int mALLOPt(int param_number
, int value
)
5149 int mALLOPt(param_number
, value
) int param_number
; int value
;
5152 if(__malloc_initialized
< 0)
5154 mstate av
= &main_arena
;
5157 (void)mutex_lock(&av
->mutex
);
5158 /* Ensure initialization/consolidation */
5159 malloc_consolidate(av
);
5161 switch(param_number
) {
5163 if (value
>= 0 && value
<= MAX_FAST_SIZE
) {
5164 set_max_fast(av
, value
);
5170 case M_TRIM_THRESHOLD
:
5171 mp_
.trim_threshold
= value
;
5175 mp_
.top_pad
= value
;
5178 case M_MMAP_THRESHOLD
:
5180 /* Forbid setting the threshold too high. */
5181 if((unsigned long)value
> HEAP_MAX_SIZE
/2)
5185 mp_
.mmap_threshold
= value
;
5194 mp_
.n_mmaps_max
= value
;
5197 case M_CHECK_ACTION
:
5198 check_action
= value
;
5201 (void)mutex_unlock(&av
->mutex
);
5207 -------------------- Alternative MORECORE functions --------------------
5212 General Requirements for MORECORE.
5214 The MORECORE function must have the following properties:
5216 If MORECORE_CONTIGUOUS is false:
5218 * MORECORE must allocate in multiples of pagesize. It will
5219 only be called with arguments that are multiples of pagesize.
5221 * MORECORE(0) must return an address that is at least
5222 MALLOC_ALIGNMENT aligned. (Page-aligning always suffices.)
5224 else (i.e. If MORECORE_CONTIGUOUS is true):
5226 * Consecutive calls to MORECORE with positive arguments
5227 return increasing addresses, indicating that space has been
5228 contiguously extended.
5230 * MORECORE need not allocate in multiples of pagesize.
5231 Calls to MORECORE need not have args of multiples of pagesize.
5233 * MORECORE need not page-align.
5237 * MORECORE may allocate more memory than requested. (Or even less,
5238 but this will generally result in a malloc failure.)
5240 * MORECORE must not allocate memory when given argument zero, but
5241 instead return one past the end address of memory from previous
5242 nonzero call. This malloc does NOT call MORECORE(0)
5243 until at least one call with positive arguments is made, so
5244 the initial value returned is not important.
5246 * Even though consecutive calls to MORECORE need not return contiguous
5247 addresses, it must be OK for malloc'ed chunks to span multiple
5248 regions in those cases where they do happen to be contiguous.
5250 * MORECORE need not handle negative arguments -- it may instead
5251 just return MORECORE_FAILURE when given negative arguments.
5252 Negative arguments are always multiples of pagesize. MORECORE
5253 must not misinterpret negative args as large positive unsigned
5254 args. You can suppress all such calls from even occurring by defining
5255 MORECORE_CANNOT_TRIM,
5257 There is some variation across systems about the type of the
5258 argument to sbrk/MORECORE. If size_t is unsigned, then it cannot
5259 actually be size_t, because sbrk supports negative args, so it is
5260 normally the signed type of the same width as size_t (sometimes
5261 declared as "intptr_t", and sometimes "ptrdiff_t"). It doesn't much
5262 matter though. Internally, we use "long" as arguments, which should
5263 work across all reasonable possibilities.
5265 Additionally, if MORECORE ever returns failure for a positive
5266 request, and HAVE_MMAP is true, then mmap is used as a noncontiguous
5267 system allocator. This is a useful backup strategy for systems with
5268 holes in address spaces -- in this case sbrk cannot contiguously
5269 expand the heap, but mmap may be able to map noncontiguous space.
5271 If you'd like mmap to ALWAYS be used, you can define MORECORE to be
5272 a function that always returns MORECORE_FAILURE.
5274 If you are using this malloc with something other than sbrk (or its
5275 emulation) to supply memory regions, you probably want to set
5276 MORECORE_CONTIGUOUS as false. As an example, here is a custom
5277 allocator kindly contributed for pre-OSX macOS. It uses virtually
5278 but not necessarily physically contiguous non-paged memory (locked
5279 in, present and won't get swapped out). You can use it by
5280 uncommenting this section, adding some #includes, and setting up the
5281 appropriate defines above:
5283 #define MORECORE osMoreCore
5284 #define MORECORE_CONTIGUOUS 0
5286 There is also a shutdown routine that should somehow be called for
5287 cleanup upon program exit.
5289 #define MAX_POOL_ENTRIES 100
5290 #define MINIMUM_MORECORE_SIZE (64 * 1024)
5291 static int next_os_pool;
5292 void *our_os_pools[MAX_POOL_ENTRIES];
5294 void *osMoreCore(int size)
5297 static void *sbrk_top = 0;
5301 if (size < MINIMUM_MORECORE_SIZE)
5302 size = MINIMUM_MORECORE_SIZE;
5303 if (CurrentExecutionLevel() == kTaskLevel)
5304 ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
5307 return (void *) MORECORE_FAILURE;
5309 // save ptrs so they can be freed during cleanup
5310 our_os_pools[next_os_pool] = ptr;
5312 ptr = (void *) ((((unsigned long) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
5313 sbrk_top = (char *) ptr + size;
5318 // we don't currently support shrink behavior
5319 return (void *) MORECORE_FAILURE;
5327 // cleanup any allocated memory pools
5328 // called as last thing before shutting down driver
5330 void osCleanupMem(void)
5334 for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
5337 PoolDeallocate(*ptr);
5346 # include <sys/param.h>
5348 /* We need a wrapper function for one of the additions of POSIX. */
5350 __posix_memalign (void **memptr
, size_t alignment
, size_t size
)
5354 /* Test whether the SIZE argument is valid. It must be a power of
5355 two multiple of sizeof (void *). */
5356 if (alignment
% sizeof (void *) != 0 || !powerof2 (alignment
) != 0)
5359 mem
= __memalign_internal (alignment
, size
);
5368 weak_alias (__posix_memalign
, posix_memalign
)
5370 weak_alias (__libc_calloc
, __calloc
) weak_alias (__libc_calloc
, calloc
)
5371 weak_alias (__libc_free
, __cfree
) weak_alias (__libc_free
, cfree
)
5372 weak_alias (__libc_free
, __free
) weak_alias (__libc_free
, free
)
5373 weak_alias (__libc_malloc
, __malloc
) weak_alias (__libc_malloc
, malloc
)
5374 weak_alias (__libc_memalign
, __memalign
) weak_alias (__libc_memalign
, memalign
)
5375 weak_alias (__libc_realloc
, __realloc
) weak_alias (__libc_realloc
, realloc
)
5376 weak_alias (__libc_valloc
, __valloc
) weak_alias (__libc_valloc
, valloc
)
5377 weak_alias (__libc_pvalloc
, __pvalloc
) weak_alias (__libc_pvalloc
, pvalloc
)
5378 weak_alias (__libc_mallinfo
, __mallinfo
) weak_alias (__libc_mallinfo
, mallinfo
)
5379 weak_alias (__libc_mallopt
, __mallopt
) weak_alias (__libc_mallopt
, mallopt
)
5381 weak_alias (__malloc_stats
, malloc_stats
)
5382 weak_alias (__malloc_usable_size
, malloc_usable_size
)
5383 weak_alias (__malloc_trim
, malloc_trim
)
5384 weak_alias (__malloc_get_state
, malloc_get_state
)
5385 weak_alias (__malloc_set_state
, malloc_set_state
)
5389 /* ------------------------------------------------------------
5392 [see ftp://g.oswego.edu/pub/misc/malloc.c for the history of dlmalloc]