old malloc implementations
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/* Malloc implementation for multiple threads without lock contention. | |
Copyright (C) 1996-2001, 2002 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Wolfram Gloger <wmglo@dent.med.uni-muenchen.de> | |
and Doug Lea <dl@cs.oswego.edu>, 1996. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 of the License, or (at your option) any later version. | |
The GNU C Library is distributed in the hope that it will be useful, | |
but WITHOUT ANY WARRANTY; without even the implied warranty of | |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, write to the Free | |
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
02111-1307 USA. */ | |
/* $Id$ | |
This work is mainly derived from malloc-2.6.4 by Doug Lea | |
<dl@cs.oswego.edu>, which is available from: | |
ftp://g.oswego.edu/pub/misc/malloc.c | |
Most of the original comments are reproduced in the code below. | |
* Why use this malloc? | |
This is not the fastest, most space-conserving, most portable, or | |
most tunable malloc ever written. However it is among the fastest | |
while also being among the most space-conserving, portable and tunable. | |
Consistent balance across these factors results in a good general-purpose | |
allocator. For a high-level description, see | |
http://g.oswego.edu/dl/html/malloc.html | |
On many systems, the standard malloc implementation is by itself not | |
thread-safe, and therefore wrapped with a single global lock around | |
all malloc-related functions. In some applications, especially with | |
multiple available processors, this can lead to contention problems | |
and bad performance. This malloc version was designed with the goal | |
to avoid waiting for locks as much as possible. Statistics indicate | |
that this goal is achieved in many cases. | |
* Synopsis of public routines | |
(Much fuller descriptions are contained in the program documentation below.) | |
ptmalloc_init(); | |
Initialize global configuration. When compiled for multiple threads, | |
this function must be called once before any other function in the | |
package. It is not required otherwise. It is called automatically | |
in the Linux/GNU C libray or when compiling with MALLOC_HOOKS. | |
malloc(size_t n); | |
Return a pointer to a newly allocated chunk of at least n bytes, or null | |
if no space is available. | |
free(Void_t* p); | |
Release the chunk of memory pointed to by p, or no effect if p is null. | |
realloc(Void_t* p, size_t n); | |
Return a pointer to a chunk of size n that contains the same data | |
as does chunk p up to the minimum of (n, p's size) bytes, or null | |
if no space is available. The returned pointer may or may not be | |
the same as p. If p is null, equivalent to malloc. Unless the | |
#define REALLOC_ZERO_BYTES_FREES below is set, realloc with a | |
size argument of zero (re)allocates a minimum-sized chunk. | |
memalign(size_t alignment, size_t n); | |
Return a pointer to a newly allocated chunk of n bytes, aligned | |
in accord with the alignment argument, which must be a power of | |
two. | |
valloc(size_t n); | |
Equivalent to memalign(pagesize, n), where pagesize is the page | |
size of the system (or as near to this as can be figured out from | |
all the includes/defines below.) | |
pvalloc(size_t n); | |
Equivalent to valloc(minimum-page-that-holds(n)), that is, | |
round up n to nearest pagesize. | |
calloc(size_t unit, size_t quantity); | |
Returns a pointer to quantity * unit bytes, with all locations | |
set to zero. | |
cfree(Void_t* p); | |
Equivalent to free(p). | |
malloc_trim(size_t pad); | |
Release all but pad bytes of freed top-most memory back | |
to the system. Return 1 if successful, else 0. | |
malloc_usable_size(Void_t* p); | |
Report the number usable allocated bytes associated with allocated | |
chunk p. This may or may not report more bytes than were requested, | |
due to alignment and minimum size constraints. | |
malloc_stats(); | |
Prints brief summary statistics on stderr. | |
mallinfo() | |
Returns (by copy) a struct containing various summary statistics. | |
mallopt(int parameter_number, int parameter_value) | |
Changes one of the tunable parameters described below. Returns | |
1 if successful in changing the parameter, else 0. | |
* Vital statistics: | |
Alignment: 8-byte | |
8 byte alignment is currently hardwired into the design. This | |
seems to suffice for all current machines and C compilers. | |
Assumed pointer representation: 4 or 8 bytes | |
Code for 8-byte pointers is untested by me but has worked | |
reliably by Wolfram Gloger, who contributed most of the | |
changes supporting this. | |
Assumed size_t representation: 4 or 8 bytes | |
Note that size_t is allowed to be 4 bytes even if pointers are 8. | |
Minimum overhead per allocated chunk: 4 or 8 bytes | |
Each malloced chunk has a hidden overhead of 4 bytes holding size | |
and status information. | |
Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead) | |
8-byte ptrs: 24/32 bytes (including, 4/8 overhead) | |
When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte | |
ptrs but 4 byte size) or 24 (for 8/8) additional bytes are | |
needed; 4 (8) for a trailing size field | |
and 8 (16) bytes for free list pointers. Thus, the minimum | |
allocatable size is 16/24/32 bytes. | |
Even a request for zero bytes (i.e., malloc(0)) returns a | |
pointer to something of the minimum allocatable size. | |
Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes | |
8-byte size_t: 2^63 - 16 bytes | |
It is assumed that (possibly signed) size_t bit values suffice to | |
represent chunk sizes. `Possibly signed' is due to the fact | |
that `size_t' may be defined on a system as either a signed or | |
an unsigned type. To be conservative, values that would appear | |
as negative numbers are avoided. | |
Requests for sizes with a negative sign bit will return a | |
minimum-sized chunk. | |
Maximum overhead wastage per allocated chunk: normally 15 bytes | |
Alignment demands, plus the minimum allocatable size restriction | |
make the normal worst-case wastage 15 bytes (i.e., up to 15 | |
more bytes will be allocated than were requested in malloc), with | |
two exceptions: | |
1. Because requests for zero bytes allocate non-zero space, | |
the worst case wastage for a request of zero bytes is 24 bytes. | |
2. For requests >= mmap_threshold that are serviced via | |
mmap(), the worst case wastage is 8 bytes plus the remainder | |
from a system page (the minimal mmap unit); typically 4096 bytes. | |
* Limitations | |
Here are some features that are NOT currently supported | |
* No automated mechanism for fully checking that all accesses | |
to malloced memory stay within their bounds. | |
* No support for compaction. | |
* Synopsis of compile-time options: | |
People have reported using previous versions of this malloc on all | |
versions of Unix, sometimes by tweaking some of the defines | |
below. It has been tested most extensively on Solaris and | |
Linux. People have also reported adapting this malloc for use in | |
stand-alone embedded systems. | |
The implementation is in straight, hand-tuned ANSI C. Among other | |
consequences, it uses a lot of macros. Because of this, to be at | |
all usable, this code should be compiled using an optimizing compiler | |
(for example gcc -O2) that can simplify expressions and control | |
paths. | |
__STD_C (default: derived from C compiler defines) | |
Nonzero if using ANSI-standard C compiler, a C++ compiler, or | |
a C compiler sufficiently close to ANSI to get away with it. | |
MALLOC_DEBUG (default: NOT defined) | |
Define to enable debugging. Adds fairly extensive assertion-based | |
checking to help track down memory errors, but noticeably slows down | |
execution. | |
MALLOC_HOOKS (default: NOT defined) | |
Define to enable support run-time replacement of the allocation | |
functions through user-defined `hooks'. | |
REALLOC_ZERO_BYTES_FREES (default: defined) | |
Define this if you think that realloc(p, 0) should be equivalent | |
to free(p). (The C standard requires this behaviour, therefore | |
it is the default.) Otherwise, since malloc returns a unique | |
pointer for malloc(0), so does realloc(p, 0). | |
HAVE_MEMCPY (default: defined) | |
Define if you are not otherwise using ANSI STD C, but still | |
have memcpy and memset in your C library and want to use them. | |
Otherwise, simple internal versions are supplied. | |
USE_MEMCPY (default: 1 if HAVE_MEMCPY is defined, 0 otherwise) | |
Define as 1 if you want the C library versions of memset and | |
memcpy called in realloc and calloc (otherwise macro versions are used). | |
At least on some platforms, the simple macro versions usually | |
outperform libc versions. | |
HAVE_MMAP (default: defined as 1) | |
Define to non-zero to optionally make malloc() use mmap() to | |
allocate very large blocks. | |
HAVE_MREMAP (default: defined as 0 unless Linux libc set) | |
Define to non-zero to optionally make realloc() use mremap() to | |
reallocate very large blocks. | |
USE_ARENAS (default: the same as HAVE_MMAP) | |
Enable support for multiple arenas, allocated using mmap(). | |
malloc_getpagesize (default: derived from system #includes) | |
Either a constant or routine call returning the system page size. | |
HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined) | |
Optionally define if you are on a system with a /usr/include/malloc.h | |
that declares struct mallinfo. It is not at all necessary to | |
define this even if you do, but will ensure consistency. | |
INTERNAL_SIZE_T (default: size_t) | |
Define to a 32-bit type (probably `unsigned int') if you are on a | |
64-bit machine, yet do not want or need to allow malloc requests of | |
greater than 2^31 to be handled. This saves space, especially for | |
very small chunks. | |
_LIBC (default: NOT defined) | |
Defined only when compiled as part of the Linux libc/glibc. | |
Also note that there is some odd internal name-mangling via defines | |
(for example, internally, `malloc' is named `mALLOc') needed | |
when compiling in this case. These look funny but don't otherwise | |
affect anything. | |
LACKS_UNISTD_H (default: undefined) | |
Define this if your system does not have a <unistd.h>. | |
MORECORE (default: sbrk) | |
The name of the routine to call to obtain more memory from the system. | |
MORECORE_FAILURE (default: -1) | |
The value returned upon failure of MORECORE. | |
MORECORE_CLEARS (default 1) | |
The degree to which the routine mapped to MORECORE zeroes out | |
memory: never (0), only for newly allocated space (1) or always | |
(2). The distinction between (1) and (2) is necessary because on | |
some systems, if the application first decrements and then | |
increments the break value, the contents of the reallocated space | |
are unspecified. | |
DEFAULT_TRIM_THRESHOLD | |
DEFAULT_TOP_PAD | |
DEFAULT_MMAP_THRESHOLD | |
DEFAULT_MMAP_MAX | |
Default values of tunable parameters (described in detail below) | |
controlling interaction with host system routines (sbrk, mmap, etc). | |
These values may also be changed dynamically via mallopt(). The | |
preset defaults are those that give best performance for typical | |
programs/systems. | |
DEFAULT_CHECK_ACTION | |
When the standard debugging hooks are in place, and a pointer is | |
detected as corrupt, do nothing (0), print an error message (1), | |
or call abort() (2). | |
*/ | |
/* | |
* Compile-time options for multiple threads: | |
USE_PTHREADS, USE_THR, USE_SPROC | |
Define one of these as 1 to select the thread interface: | |
POSIX threads, Solaris threads or SGI sproc's, respectively. | |
If none of these is defined as non-zero, you get a `normal' | |
malloc implementation which is not thread-safe. Support for | |
multiple threads requires HAVE_MMAP=1. As an exception, when | |
compiling for GNU libc, i.e. when _LIBC is defined, then none of | |
the USE_... symbols have to be defined. | |
HEAP_MIN_SIZE | |
HEAP_MAX_SIZE | |
When thread support is enabled, additional `heap's are created | |
with mmap calls. These are limited in size; HEAP_MIN_SIZE should | |
be a multiple of the page size, while HEAP_MAX_SIZE must be a power | |
of two for alignment reasons. HEAP_MAX_SIZE should be at least | |
twice as large as the mmap threshold. | |
THREAD_STATS | |
When this is defined as non-zero, some statistics on mutex locking | |
are computed. | |
*/ | |
/* Preliminaries */ | |
#ifndef __STD_C | |
#if defined (__STDC__) | |
#define __STD_C 1 | |
#else | |
#if __cplusplus | |
#define __STD_C 1 | |
#else | |
#define __STD_C 0 | |
#endif /*__cplusplus*/ | |
#endif /*__STDC__*/ | |
#endif /*__STD_C*/ | |
#ifndef Void_t | |
#if __STD_C | |
#define Void_t void | |
#else | |
#define Void_t char | |
#endif | |
#endif /*Void_t*/ | |
#define _GNU_SOURCE | |
#include <features.h> | |
#define _LIBC 1 | |
#define NOT_IN_libc 1 | |
#if __STD_C | |
# include <stddef.h> /* for size_t */ | |
# if defined _LIBC || defined MALLOC_HOOKS | |
# include <stdlib.h> /* for getenv(), abort() */ | |
# endif | |
#else | |
# include <sys/types.h> | |
# if defined _LIBC || defined MALLOC_HOOKS | |
extern char* getenv(); | |
# endif | |
#endif | |
/* newlib modifications */ | |
#include <libc-symbols.h> | |
#include <sys/types.h> | |
extern void __pthread_initialize (void) __attribute__((weak)); | |
extern void *__mmap (void *__addr, size_t __len, int __prot, | |
int __flags, int __fd, off_t __offset); | |
extern int __munmap (void *__addr, size_t __len); | |
extern void *__mremap (void *__addr, size_t __old_len, size_t __new_len, | |
int __may_move); | |
extern int __getpagesize (void); | |
#define __libc_enable_secure 1 | |
/* Macros for handling mutexes and thread-specific data. This is | |
included early, because some thread-related header files (such as | |
pthread.h) should be included before any others. */ | |
#include <bits/libc-lock.h> | |
#include "thread-m.h" | |
void *(*__malloc_internal_tsd_get) (enum __libc_tsd_key_t) = NULL; | |
int (*__malloc_internal_tsd_set) (enum __libc_tsd_key_t, | |
__const void *) = NULL; | |
weak_alias(__malloc_internal_tsd_get, __libc_internal_tsd_get) | |
weak_alias(__malloc_internal_tsd_set, __libc_internal_tsd_set) | |
#ifdef __cplusplus | |
extern "C" { | |
#endif | |
#include <errno.h> | |
#include <stdio.h> /* needed for malloc_stats */ | |
/* | |
Compile-time options | |
*/ | |
/* | |
Debugging: | |
Because freed chunks may be overwritten with link fields, this | |
malloc will often die when freed memory is overwritten by user | |
programs. This can be very effective (albeit in an annoying way) | |
in helping track down dangling pointers. | |
If you compile with -DMALLOC_DEBUG, a number of assertion checks are | |
enabled that will catch more memory errors. You probably won't be | |
able to make much sense of the actual assertion errors, but they | |
should help you locate incorrectly overwritten memory. The | |
checking is fairly extensive, and will slow down execution | |
noticeably. Calling malloc_stats or mallinfo with MALLOC_DEBUG set will | |
attempt to check every non-mmapped allocated and free chunk in the | |
course of computing the summaries. (By nature, mmapped regions | |
cannot be checked very much automatically.) | |
Setting MALLOC_DEBUG may also be helpful if you are trying to modify | |
this code. The assertions in the check routines spell out in more | |
detail the assumptions and invariants underlying the algorithms. | |
*/ | |
#if MALLOC_DEBUG | |
#include <assert.h> | |
#else | |
#define assert(x) ((void)0) | |
#endif | |
/* | |
INTERNAL_SIZE_T is the word-size used for internal bookkeeping | |
of chunk sizes. On a 64-bit machine, you can reduce malloc | |
overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int' | |
at the expense of not being able to handle requests greater than | |
2^31. This limitation is hardly ever a concern; you are encouraged | |
to set this. However, the default version is the same as size_t. | |
*/ | |
#ifndef INTERNAL_SIZE_T | |
#define INTERNAL_SIZE_T size_t | |
#endif | |
/* | |
REALLOC_ZERO_BYTES_FREES should be set if a call to realloc with | |
zero bytes should be the same as a call to free. The C standard | |
requires this. Otherwise, since this malloc returns a unique pointer | |
for malloc(0), so does realloc(p, 0). | |
*/ | |
#define REALLOC_ZERO_BYTES_FREES | |
/* | |
HAVE_MEMCPY should be defined if you are not otherwise using | |
ANSI STD C, but still have memcpy and memset in your C library | |
and want to use them in calloc and realloc. Otherwise simple | |
macro versions are defined here. | |
USE_MEMCPY should be defined as 1 if you actually want to | |
have memset and memcpy called. People report that the macro | |
versions are often enough faster than libc versions on many | |
systems that it is better to use them. | |
*/ | |
#define HAVE_MEMCPY 1 | |
#ifndef USE_MEMCPY | |
#ifdef HAVE_MEMCPY | |
#define USE_MEMCPY 1 | |
#else | |
#define USE_MEMCPY 0 | |
#endif | |
#endif | |
#if (__STD_C || defined(HAVE_MEMCPY)) | |
#if __STD_C | |
void* memset(void*, int, size_t); | |
void* memcpy(void*, const void*, size_t); | |
void* memmove(void*, const void*, size_t); | |
#else | |
Void_t* memset(); | |
Void_t* memcpy(); | |
Void_t* memmove(); | |
#endif | |
#endif | |
/* The following macros are only invoked with (2n+1)-multiples of | |
INTERNAL_SIZE_T units, with a positive integer n. This is exploited | |
for fast inline execution when n is small. If the regions to be | |
copied do overlap, the destination lies always _below_ the source. */ | |
#if USE_MEMCPY | |
#define MALLOC_ZERO(charp, nbytes) \ | |
do { \ | |
INTERNAL_SIZE_T mzsz = (nbytes); \ | |
if(mzsz <= 9*sizeof(mzsz)) { \ | |
INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp); \ | |
if(mzsz >= 5*sizeof(mzsz)) { *mz++ = 0; \ | |
*mz++ = 0; \ | |
if(mzsz >= 7*sizeof(mzsz)) { *mz++ = 0; \ | |
*mz++ = 0; \ | |
if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0; \ | |
*mz++ = 0; }}} \ | |
*mz++ = 0; \ | |
*mz++ = 0; \ | |
*mz = 0; \ | |
} else memset((charp), 0, mzsz); \ | |
} while(0) | |
/* If the regions overlap, dest is always _below_ src. */ | |
#define MALLOC_COPY(dest,src,nbytes,overlap) \ | |
do { \ | |
INTERNAL_SIZE_T mcsz = (nbytes); \ | |
if(mcsz <= 9*sizeof(mcsz)) { \ | |
INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src); \ | |
INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest); \ | |
if(mcsz >= 5*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ | |
*mcdst++ = *mcsrc++; \ | |
if(mcsz >= 7*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ | |
*mcdst++ = *mcsrc++; \ | |
if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ | |
*mcdst++ = *mcsrc++; }}} \ | |
*mcdst++ = *mcsrc++; \ | |
*mcdst++ = *mcsrc++; \ | |
*mcdst = *mcsrc ; \ | |
} else if(overlap) \ | |
memmove(dest, src, mcsz); \ | |
else \ | |
memcpy(dest, src, mcsz); \ | |
} while(0) | |
#else /* !USE_MEMCPY */ | |
/* Use Duff's device for good zeroing/copying performance. */ | |
#define MALLOC_ZERO(charp, nbytes) \ | |
do { \ | |
INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp); \ | |
long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ | |
if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ | |
switch (mctmp) { \ | |
case 0: for(;;) { *mzp++ = 0; \ | |
case 7: *mzp++ = 0; \ | |
case 6: *mzp++ = 0; \ | |
case 5: *mzp++ = 0; \ | |
case 4: *mzp++ = 0; \ | |
case 3: *mzp++ = 0; \ | |
case 2: *mzp++ = 0; \ | |
case 1: *mzp++ = 0; if(mcn <= 0) break; mcn--; } \ | |
} \ | |
} while(0) | |
/* If the regions overlap, dest is always _below_ src. */ | |
#define MALLOC_COPY(dest,src,nbytes,overlap) \ | |
do { \ | |
INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \ | |
INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \ | |
long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ | |
if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ | |
switch (mctmp) { \ | |
case 0: for(;;) { *mcdst++ = *mcsrc++; \ | |
case 7: *mcdst++ = *mcsrc++; \ | |
case 6: *mcdst++ = *mcsrc++; \ | |
case 5: *mcdst++ = *mcsrc++; \ | |
case 4: *mcdst++ = *mcsrc++; \ | |
case 3: *mcdst++ = *mcsrc++; \ | |
case 2: *mcdst++ = *mcsrc++; \ | |
case 1: *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; } \ | |
} \ | |
} while(0) | |
#endif | |
#ifndef LACKS_UNISTD_H | |
# include <unistd.h> | |
#endif | |
/* | |
Define HAVE_MMAP to optionally make malloc() use mmap() to allocate | |
very large blocks. These will be returned to the operating system | |
immediately after a free(). HAVE_MMAP is also a prerequisite to | |
support multiple `arenas' (see USE_ARENAS below). | |
*/ | |
#ifndef HAVE_MMAP | |
# ifdef _POSIX_MAPPED_FILES | |
# define HAVE_MMAP 1 | |
# endif | |
#endif | |
/* | |
Define HAVE_MREMAP to make realloc() use mremap() to re-allocate | |
large blocks. This is currently only possible on Linux with | |
kernel versions newer than 1.3.77. | |
*/ | |
#ifndef HAVE_MREMAP | |
#define HAVE_MREMAP defined(__linux__) | |
#endif | |
/* Define USE_ARENAS to enable support for multiple `arenas'. These | |
are allocated using mmap(), are necessary for threads and | |
occasionally useful to overcome address space limitations affecting | |
sbrk(). */ | |
#ifndef USE_ARENAS | |
#define USE_ARENAS HAVE_MMAP | |
#endif | |
#if HAVE_MMAP | |
#include <unistd.h> | |
#include <fcntl.h> | |
#include <sys/mman.h> | |
#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) | |
#define MAP_ANONYMOUS MAP_ANON | |
#endif | |
#if !defined(MAP_FAILED) | |
#define MAP_FAILED ((char*)-1) | |
#endif | |
#ifndef MAP_NORESERVE | |
# ifdef MAP_AUTORESRV | |
# define MAP_NORESERVE MAP_AUTORESRV | |
# else | |
# define MAP_NORESERVE 0 | |
# endif | |
#endif | |
#endif /* HAVE_MMAP */ | |
/* | |
Access to system page size. To the extent possible, this malloc | |
manages memory from the system in page-size units. | |
The following mechanics for getpagesize were adapted from | |
bsd/gnu getpagesize.h | |
*/ | |
#ifndef malloc_getpagesize | |
# ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */ | |
# ifndef _SC_PAGE_SIZE | |
# define _SC_PAGE_SIZE _SC_PAGESIZE | |
# endif | |
# endif | |
# ifdef _SC_PAGE_SIZE | |
# define malloc_getpagesize sysconf(_SC_PAGE_SIZE) | |
# else | |
# if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE) | |
extern size_t getpagesize(); | |
# define malloc_getpagesize getpagesize() | |
# else | |
# include <sys/param.h> | |
# ifdef EXEC_PAGESIZE | |
# define malloc_getpagesize EXEC_PAGESIZE | |
# else | |
# ifdef NBPG | |
# ifndef CLSIZE | |
# define malloc_getpagesize NBPG | |
# else | |
# define malloc_getpagesize (NBPG * CLSIZE) | |
# endif | |
# else | |
# ifdef NBPC | |
# define malloc_getpagesize NBPC | |
# else | |
# ifdef PAGESIZE | |
# define malloc_getpagesize PAGESIZE | |
# else | |
# define malloc_getpagesize (4096) /* just guess */ | |
# endif | |
# endif | |
# endif | |
# endif | |
# endif | |
# endif | |
#endif | |
/* | |
This version of malloc supports the standard SVID/XPG mallinfo | |
routine that returns a struct containing the same kind of | |
information you can get from malloc_stats. It should work on | |
any SVID/XPG compliant system that has a /usr/include/malloc.h | |
defining struct mallinfo. (If you'd like to install such a thing | |
yourself, cut out the preliminary declarations as described above | |
and below and save them in a malloc.h file. But there's no | |
compelling reason to bother to do this.) | |
The main declaration needed is the mallinfo struct that is returned | |
(by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a | |
bunch of fields, most of which are not even meaningful in this | |
version of malloc. Some of these fields are are instead filled by | |
mallinfo() with other numbers that might possibly be of interest. | |
HAVE_USR_INCLUDE_MALLOC_H should be set if you have a | |
/usr/include/malloc.h file that includes a declaration of struct | |
mallinfo. If so, it is included; else an SVID2/XPG2 compliant | |
version is declared below. These must be precisely the same for | |
mallinfo() to work. | |
*/ | |
/* #define HAVE_USR_INCLUDE_MALLOC_H */ | |
#if HAVE_USR_INCLUDE_MALLOC_H | |
# include "/usr/include/malloc.h" | |
#else | |
# ifdef _LIBC | |
# include "malloc.h" | |
# else | |
# include "ptmalloc.h" | |
# endif | |
#endif | |
#include <bp-checks.h> | |
#ifndef DEFAULT_TRIM_THRESHOLD | |
#define DEFAULT_TRIM_THRESHOLD (128 * 1024) | |
#endif | |
/* | |
M_TRIM_THRESHOLD is the maximum amount of unused top-most memory | |
to keep before releasing via malloc_trim in free(). | |
Automatic trimming is mainly useful in long-lived programs. | |
Because trimming via sbrk can be slow on some systems, and can | |
sometimes be wasteful (in cases where programs immediately | |
afterward allocate more large chunks) the value should be high | |
enough so that your overall system performance would improve by | |
releasing. | |
The trim threshold and the mmap control parameters (see below) | |
can be traded off with one another. Trimming and mmapping are | |
two different ways of releasing unused memory back to the | |
system. Between these two, it is often possible to keep | |
system-level demands of a long-lived program down to a bare | |
minimum. For example, in one test suite of sessions measuring | |
the XF86 X server on Linux, using a trim threshold of 128K and a | |
mmap threshold of 192K led to near-minimal long term resource | |
consumption. | |
If you are using this malloc in a long-lived program, it should | |
pay to experiment with these values. As a rough guide, you | |
might set to a value close to the average size of a process | |
(program) running on your system. Releasing this much memory | |
would allow such a process to run in memory. Generally, it's | |
worth it to tune for trimming rather than memory mapping when a | |
program undergoes phases where several large chunks are | |
allocated and released in ways that can reuse each other's | |
storage, perhaps mixed with phases where there are no such | |
chunks at all. And in well-behaved long-lived programs, | |
controlling release of large blocks via trimming versus mapping | |
is usually faster. | |
However, in most programs, these parameters serve mainly as | |
protection against the system-level effects of carrying around | |
massive amounts of unneeded memory. Since frequent calls to | |
sbrk, mmap, and munmap otherwise degrade performance, the default | |
parameters are set to relatively high values that serve only as | |
safeguards. | |
The default trim value is high enough to cause trimming only in | |
fairly extreme (by current memory consumption standards) cases. | |
It must be greater than page size to have any useful effect. To | |
disable trimming completely, you can set to (unsigned long)(-1); | |
*/ | |
#ifndef DEFAULT_TOP_PAD | |
#define DEFAULT_TOP_PAD (0) | |
#endif | |
/* | |
M_TOP_PAD is the amount of extra `padding' space to allocate or | |
retain whenever sbrk is called. It is used in two ways internally: | |
* When sbrk is called to extend the top of the arena to satisfy | |
a new malloc request, this much padding is added to the sbrk | |
request. | |
* When malloc_trim is called automatically from free(), | |
it is used as the `pad' argument. | |
In both cases, the actual amount of padding is rounded | |
so that the end of the arena is always a system page boundary. | |
The main reason for using padding is to avoid calling sbrk so | |
often. Having even a small pad greatly reduces the likelihood | |
that nearly every malloc request during program start-up (or | |
after trimming) will invoke sbrk, which needlessly wastes | |
time. | |
Automatic rounding-up to page-size units is normally sufficient | |
to avoid measurable overhead, so the default is 0. However, in | |
systems where sbrk is relatively slow, it can pay to increase | |
this value, at the expense of carrying around more memory than | |
the program needs. | |
*/ | |
#ifndef DEFAULT_MMAP_THRESHOLD | |
#define DEFAULT_MMAP_THRESHOLD (128 * 1024) | |
#endif | |
/* | |
M_MMAP_THRESHOLD is the request size threshold for using mmap() | |
to service a request. Requests of at least this size that cannot | |
be allocated using already-existing space will be serviced via mmap. | |
(If enough normal freed space already exists it is used instead.) | |
Using mmap segregates relatively large chunks of memory so that | |
they can be individually obtained and released from the host | |
system. A request serviced through mmap is never reused by any | |
other request (at least not directly; the system may just so | |
happen to remap successive requests to the same locations). | |
Segregating space in this way has the benefit that mmapped space | |
can ALWAYS be individually released back to the system, which | |
helps keep the system level memory demands of a long-lived | |
program low. Mapped memory can never become `locked' between | |
other chunks, as can happen with normally allocated chunks, which | |
menas that even trimming via malloc_trim would not release them. | |
However, it has the disadvantages that: | |
1. The space cannot be reclaimed, consolidated, and then | |
used to service later requests, as happens with normal chunks. | |
2. It can lead to more wastage because of mmap page alignment | |
requirements | |
3. It causes malloc performance to be more dependent on host | |
system memory management support routines which may vary in | |
implementation quality and may impose arbitrary | |
limitations. Generally, servicing a request via normal | |
malloc steps is faster than going through a system's mmap. | |
All together, these considerations should lead you to use mmap | |
only for relatively large requests. | |
*/ | |
#ifndef DEFAULT_MMAP_MAX | |
#if HAVE_MMAP | |
#define DEFAULT_MMAP_MAX (1024) | |
#else | |
#define DEFAULT_MMAP_MAX (0) | |
#endif | |
#endif | |
/* | |
M_MMAP_MAX is the maximum number of requests to simultaneously | |
service using mmap. This parameter exists because: | |
1. Some systems have a limited number of internal tables for | |
use by mmap. | |
2. In most systems, overreliance on mmap can degrade overall | |
performance. | |
3. If a program allocates many large regions, it is probably | |
better off using normal sbrk-based allocation routines that | |
can reclaim and reallocate normal heap memory. Using a | |
small value allows transition into this mode after the | |
first few allocations. | |
Setting to 0 disables all use of mmap. If HAVE_MMAP is not set, | |
the default value is 0, and attempts to set it to non-zero values | |
in mallopt will fail. | |
*/ | |
#ifndef DEFAULT_CHECK_ACTION | |
#define DEFAULT_CHECK_ACTION 1 | |
#endif | |
/* What to do if the standard debugging hooks are in place and a | |
corrupt pointer is detected: do nothing (0), print an error message | |
(1), or call abort() (2). */ | |
#define HEAP_MIN_SIZE (32*1024) | |
#define HEAP_MAX_SIZE (1024*1024) /* must be a power of two */ | |
/* HEAP_MIN_SIZE and HEAP_MAX_SIZE limit the size of mmap()ed heaps | |
that are dynamically created for multi-threaded programs. The | |
maximum size must be a power of two, for fast determination of | |
which heap belongs to a chunk. It should be much larger than | |
the mmap threshold, so that requests with a size just below that | |
threshold can be fulfilled without creating too many heaps. | |
*/ | |
#ifndef THREAD_STATS | |
#define THREAD_STATS 0 | |
#endif | |
/* If THREAD_STATS is non-zero, some statistics on mutex locking are | |
computed. */ | |
/* Macro to set errno. */ | |
#ifndef __set_errno | |
# define __set_errno(val) errno = (val) | |
#endif | |
/* On some platforms we can compile internal, not exported functions better. | |
Let the environment provide a macro and define it to be empty if it | |
is not available. */ | |
#ifndef internal_function | |
# define internal_function | |
#endif | |
/* | |
Special defines for the Linux/GNU C library. | |
*/ | |
#ifdef _LIBC | |
#if __STD_C | |
Void_t * __default_morecore (ptrdiff_t); | |
Void_t *(*__morecore)(ptrdiff_t) = __default_morecore; | |
#else | |
Void_t * __default_morecore (); | |
Void_t *(*__morecore)() = __default_morecore; | |
#endif | |
#define MORECORE (*__morecore) | |
#define MORECORE_FAILURE 0 | |
#ifndef MORECORE_CLEARS | |
#define MORECORE_CLEARS 1 | |
#endif | |
static size_t __libc_pagesize; | |
#define access __access | |
#define mmap __mmap | |
#define munmap __munmap | |
#define mremap __mremap | |
#define mprotect __mprotect | |
#undef malloc_getpagesize | |
#define malloc_getpagesize __libc_pagesize | |
#else /* _LIBC */ | |
#if __STD_C | |
extern Void_t* sbrk(ptrdiff_t); | |
#else | |
extern Void_t* sbrk(); | |
#endif | |
#ifndef MORECORE | |
#define MORECORE sbrk | |
#endif | |
#ifndef MORECORE_FAILURE | |
#define MORECORE_FAILURE -1 | |
#endif | |
#ifndef MORECORE_CLEARS | |
#define MORECORE_CLEARS 1 | |
#endif | |
#endif /* _LIBC */ | |
#ifdef _LIBC | |
#define cALLOc __libc_calloc | |
#define fREe __libc_free | |
#define mALLOc __libc_malloc | |
#define mEMALIGn __libc_memalign | |
#define rEALLOc __libc_realloc | |
#define vALLOc __libc_valloc | |
#define pvALLOc __libc_pvalloc | |
#define mALLINFo __libc_mallinfo | |
#define mALLOPt __libc_mallopt | |
#define mALLOC_STATs __malloc_stats | |
#define mALLOC_USABLE_SIZe __malloc_usable_size | |
#define mALLOC_TRIm __malloc_trim | |
#define mALLOC_GET_STATe __malloc_get_state | |
#define mALLOC_SET_STATe __malloc_set_state | |
#else | |
#define cALLOc calloc | |
#define fREe free | |
#define mALLOc malloc | |
#define mEMALIGn memalign | |
#define rEALLOc realloc | |
#define vALLOc valloc | |
#define pvALLOc pvalloc | |
#define mALLINFo mallinfo | |
#define mALLOPt mallopt | |
#define mALLOC_STATs malloc_stats | |
#define mALLOC_USABLE_SIZe malloc_usable_size | |
#define mALLOC_TRIm malloc_trim | |
#define mALLOC_GET_STATe malloc_get_state | |
#define mALLOC_SET_STATe malloc_set_state | |
#endif | |
/* Public routines */ | |
#if __STD_C | |
#ifndef _LIBC | |
void ptmalloc_init(void); | |
#endif | |
Void_t* mALLOc(size_t); | |
void fREe(Void_t*); | |
Void_t* rEALLOc(Void_t*, size_t); | |
Void_t* mEMALIGn(size_t, size_t); | |
Void_t* vALLOc(size_t); | |
Void_t* pvALLOc(size_t); | |
Void_t* cALLOc(size_t, size_t); | |
void cfree(Void_t*); | |
int mALLOC_TRIm(size_t); | |
size_t mALLOC_USABLE_SIZe(Void_t*); | |
void mALLOC_STATs(void); | |
int mALLOPt(int, int); | |
struct mallinfo mALLINFo(void); | |
Void_t* mALLOC_GET_STATe(void); | |
int mALLOC_SET_STATe(Void_t*); | |
#else /* !__STD_C */ | |
#ifndef _LIBC | |
void ptmalloc_init(); | |
#endif | |
Void_t* mALLOc(); | |
void fREe(); | |
Void_t* rEALLOc(); | |
Void_t* mEMALIGn(); | |
Void_t* vALLOc(); | |
Void_t* pvALLOc(); | |
Void_t* cALLOc(); | |
void cfree(); | |
int mALLOC_TRIm(); | |
size_t mALLOC_USABLE_SIZe(); | |
void mALLOC_STATs(); | |
int mALLOPt(); | |
struct mallinfo mALLINFo(); | |
Void_t* mALLOC_GET_STATe(); | |
int mALLOC_SET_STATe(); | |
#endif /* __STD_C */ | |
#ifdef __cplusplus | |
} /* end of extern "C" */ | |
#endif | |
#if !defined(NO_THREADS) && !HAVE_MMAP | |
"Can't have threads support without mmap" | |
#endif | |
#if USE_ARENAS && !HAVE_MMAP | |
"Can't have multiple arenas without mmap" | |
#endif | |
/* | |
Type declarations | |
*/ | |
struct malloc_chunk | |
{ | |
INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */ | |
INTERNAL_SIZE_T size; /* Size in bytes, including overhead. */ | |
struct malloc_chunk* fd; /* double links -- used only if free. */ | |
struct malloc_chunk* bk; | |
}; | |
typedef struct malloc_chunk* mchunkptr; | |
/* | |
malloc_chunk details: | |
(The following includes lightly edited explanations by Colin Plumb.) | |
Chunks of memory are maintained using a `boundary tag' method as | |
described in e.g., Knuth or Standish. (See the paper by Paul | |
Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a | |
survey of such techniques.) Sizes of free chunks are stored both | |
in the front of each chunk and at the end. This makes | |
consolidating fragmented chunks into bigger chunks very fast. The | |
size fields also hold bits representing whether chunks are free or | |
in use. | |
An allocated chunk looks like this: | |
chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| Size of previous chunk, if allocated | | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| Size of chunk, in bytes |P| | |
mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| User data starts here... . | |
. . | |
. (malloc_usable_space() bytes) . | |
. | | |
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| Size of chunk | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
Where "chunk" is the front of the chunk for the purpose of most of | |
the malloc code, but "mem" is the pointer that is returned to the | |
user. "Nextchunk" is the beginning of the next contiguous chunk. | |
Chunks always begin on even word boundaries, so the mem portion | |
(which is returned to the user) is also on an even word boundary, and | |
thus double-word aligned. | |
Free chunks are stored in circular doubly-linked lists, and look like this: | |
chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| Size of previous chunk | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
`head:' | Size of chunk, in bytes |P| | |
mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| Forward pointer to next chunk in list | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| Back pointer to previous chunk in list | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| Unused space (may be 0 bytes long) . | |
. . | |
. | | |
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
`foot:' | Size of chunk, in bytes | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
The P (PREV_INUSE) bit, stored in the unused low-order bit of the | |
chunk size (which is always a multiple of two words), is an in-use | |
bit for the *previous* chunk. If that bit is *clear*, then the | |
word before the current chunk size contains the previous chunk | |
size, and can be used to find the front of the previous chunk. | |
(The very first chunk allocated always has this bit set, | |
preventing access to non-existent (or non-owned) memory.) | |
Note that the `foot' of the current chunk is actually represented | |
as the prev_size of the NEXT chunk. (This makes it easier to | |
deal with alignments etc). | |
The two exceptions to all this are | |
1. The special chunk `top', which doesn't bother using the | |
trailing size field since there is no | |
next contiguous chunk that would have to index off it. (After | |
initialization, `top' is forced to always exist. If it would | |
become less than MINSIZE bytes long, it is replenished via | |
malloc_extend_top.) | |
2. Chunks allocated via mmap, which have the second-lowest-order | |
bit (IS_MMAPPED) set in their size fields. Because they are | |
never merged or traversed from any other chunk, they have no | |
foot size or inuse information. | |
Available chunks are kept in any of several places (all declared below): | |
* `av': An array of chunks serving as bin headers for consolidated | |
chunks. Each bin is doubly linked. The bins are approximately | |
proportionally (log) spaced. There are a lot of these bins | |
(128). This may look excessive, but works very well in | |
practice. All procedures maintain the invariant that no | |
consolidated chunk physically borders another one. Chunks in | |
bins are kept in size order, with ties going to the | |
approximately least recently used chunk. | |
The chunks in each bin are maintained in decreasing sorted order by | |
size. This is irrelevant for the small bins, which all contain | |
the same-sized chunks, but facilitates best-fit allocation for | |
larger chunks. (These lists are just sequential. Keeping them in | |
order almost never requires enough traversal to warrant using | |
fancier ordered data structures.) Chunks of the same size are | |
linked with the most recently freed at the front, and allocations | |
are taken from the back. This results in LRU or FIFO allocation | |
order, which tends to give each chunk an equal opportunity to be | |
consolidated with adjacent freed chunks, resulting in larger free | |
chunks and less fragmentation. | |
* `top': The top-most available chunk (i.e., the one bordering the | |
end of available memory) is treated specially. It is never | |
included in any bin, is used only if no other chunk is | |
available, and is released back to the system if it is very | |
large (see M_TRIM_THRESHOLD). | |
* `last_remainder': A bin holding only the remainder of the | |
most recently split (non-top) chunk. This bin is checked | |
before other non-fitting chunks, so as to provide better | |
locality for runs of sequentially allocated chunks. | |
* Implicitly, through the host system's memory mapping tables. | |
If supported, requests greater than a threshold are usually | |
serviced via calls to mmap, and then later released via munmap. | |
*/ | |
/* | |
Bins | |
The bins are an array of pairs of pointers serving as the | |
heads of (initially empty) doubly-linked lists of chunks, laid out | |
in a way so that each pair can be treated as if it were in a | |
malloc_chunk. (This way, the fd/bk offsets for linking bin heads | |
and chunks are the same). | |
Bins for sizes < 512 bytes contain chunks of all the same size, spaced | |
8 bytes apart. Larger bins are approximately logarithmically | |
spaced. (See the table below.) | |
Bin layout: | |
64 bins of size 8 | |
32 bins of size 64 | |
16 bins of size 512 | |
8 bins of size 4096 | |
4 bins of size 32768 | |
2 bins of size 262144 | |
1 bin of size what's left | |
There is actually a little bit of slop in the numbers in bin_index | |
for the sake of speed. This makes no difference elsewhere. | |
The special chunks `top' and `last_remainder' get their own bins, | |
(this is implemented via yet more trickery with the av array), | |
although `top' is never properly linked to its bin since it is | |
always handled specially. | |
*/ | |
#define NAV 128 /* number of bins */ | |
typedef struct malloc_chunk* mbinptr; | |
/* An arena is a configuration of malloc_chunks together with an array | |
of bins. With multiple threads, it must be locked via a mutex | |
before changing its data structures. One or more `heaps' are | |
associated with each arena, except for the main_arena, which is | |
associated only with the `main heap', i.e. the conventional free | |
store obtained with calls to MORECORE() (usually sbrk). The `av' | |
array is never mentioned directly in the code, but instead used via | |
bin access macros. */ | |
typedef struct _arena { | |
mbinptr av[2*NAV + 2]; | |
struct _arena *next; | |
size_t size; | |
#if THREAD_STATS | |
long stat_lock_direct, stat_lock_loop, stat_lock_wait; | |
#endif | |
mutex_t mutex; | |
} arena; | |
/* A heap is a single contiguous memory region holding (coalesceable) | |
malloc_chunks. It is allocated with mmap() and always starts at an | |
address aligned to HEAP_MAX_SIZE. Not used unless compiling with | |
USE_ARENAS. */ | |
typedef struct _heap_info { | |
arena *ar_ptr; /* Arena for this heap. */ | |
struct _heap_info *prev; /* Previous heap. */ | |
size_t size; /* Current size in bytes. */ | |
size_t pad; /* Make sure the following data is properly aligned. */ | |
} heap_info; | |
/* | |
Static functions (forward declarations) | |
*/ | |
#if __STD_C | |
static void chunk_free(arena *ar_ptr, mchunkptr p) internal_function; | |
static mchunkptr chunk_alloc(arena *ar_ptr, INTERNAL_SIZE_T size) | |
internal_function; | |
static mchunkptr chunk_realloc(arena *ar_ptr, mchunkptr oldp, | |
INTERNAL_SIZE_T oldsize, INTERNAL_SIZE_T nb) | |
internal_function; | |
static mchunkptr chunk_align(arena *ar_ptr, INTERNAL_SIZE_T nb, | |
size_t alignment) internal_function; | |
static int main_trim(size_t pad) internal_function; | |
#if USE_ARENAS | |
static int heap_trim(heap_info *heap, size_t pad) internal_function; | |
#endif | |
#if defined _LIBC || defined MALLOC_HOOKS | |
static Void_t* malloc_check(size_t sz, const Void_t *caller); | |
static void free_check(Void_t* mem, const Void_t *caller); | |
static Void_t* realloc_check(Void_t* oldmem, size_t bytes, | |
const Void_t *caller); | |
static Void_t* memalign_check(size_t alignment, size_t bytes, | |
const Void_t *caller); | |
#ifndef NO_THREADS | |
static Void_t* malloc_starter(size_t sz, const Void_t *caller); | |
static void free_starter(Void_t* mem, const Void_t *caller); | |
static Void_t* malloc_atfork(size_t sz, const Void_t *caller); | |
static void free_atfork(Void_t* mem, const Void_t *caller); | |
#endif | |
#endif | |
#else | |
static void chunk_free(); | |
static mchunkptr chunk_alloc(); | |
static mchunkptr chunk_realloc(); | |
static mchunkptr chunk_align(); | |
static int main_trim(); | |
#if USE_ARENAS | |
static int heap_trim(); | |
#endif | |
#if defined _LIBC || defined MALLOC_HOOKS | |
static Void_t* malloc_check(); | |
static void free_check(); | |
static Void_t* realloc_check(); | |
static Void_t* memalign_check(); | |
#ifndef NO_THREADS | |
static Void_t* malloc_starter(); | |
static void free_starter(); | |
static Void_t* malloc_atfork(); | |
static void free_atfork(); | |
#endif | |
#endif | |
#endif | |
/* sizes, alignments */ | |
#define SIZE_SZ (sizeof(INTERNAL_SIZE_T)) | |
/* Allow the default to be overwritten on the compiler command line. */ | |
#ifndef MALLOC_ALIGNMENT | |
# define MALLOC_ALIGNMENT (SIZE_SZ + SIZE_SZ) | |
#endif | |
#define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1) | |
#define MINSIZE (sizeof(struct malloc_chunk)) | |
/* conversion from malloc headers to user pointers, and back */ | |
#define chunk2mem(p) ((Void_t*)((char*)(p) + 2*SIZE_SZ)) | |
#define mem2chunk(mem) chunk_at_offset((mem), -2*SIZE_SZ) | |
/* pad request bytes into a usable size, return non-zero on overflow */ | |
#define request2size(req, nb) \ | |
((nb = (req) + (SIZE_SZ + MALLOC_ALIGN_MASK)),\ | |
((long)nb <= 0 || nb < (INTERNAL_SIZE_T) (req) \ | |
? (__set_errno (ENOMEM), 1) \ | |
: ((nb < (MINSIZE + MALLOC_ALIGN_MASK) \ | |
? (nb = MINSIZE) : (nb &= ~MALLOC_ALIGN_MASK)), 0))) | |
/* Check if m has acceptable alignment */ | |
#define aligned_OK(m) (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0) | |
/* | |
Physical chunk operations | |
*/ | |
/* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */ | |
#define PREV_INUSE 0x1UL | |
/* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */ | |
#define IS_MMAPPED 0x2UL | |
/* Bits to mask off when extracting size */ | |
#define SIZE_BITS (PREV_INUSE|IS_MMAPPED) | |
/* Ptr to next physical malloc_chunk. */ | |
#define next_chunk(p) chunk_at_offset((p), (p)->size & ~PREV_INUSE) | |
/* Ptr to previous physical malloc_chunk */ | |
#define prev_chunk(p) chunk_at_offset((p), -(p)->prev_size) | |
/* Treat space at ptr + offset as a chunk */ | |
#define chunk_at_offset(p, s) BOUNDED_1((mchunkptr)(((char*)(p)) + (s))) | |
/* | |
Dealing with use bits | |
*/ | |
/* extract p's inuse bit */ | |
#define inuse(p) (next_chunk(p)->size & PREV_INUSE) | |
/* extract inuse bit of previous chunk */ | |
#define prev_inuse(p) ((p)->size & PREV_INUSE) | |
/* check for mmap()'ed chunk */ | |
#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED) | |
/* set/clear chunk as in use without otherwise disturbing */ | |
#define set_inuse(p) (next_chunk(p)->size |= PREV_INUSE) | |
#define clear_inuse(p) (next_chunk(p)->size &= ~PREV_INUSE) | |
/* check/set/clear inuse bits in known places */ | |
#define inuse_bit_at_offset(p, s) \ | |
(chunk_at_offset((p), (s))->size & PREV_INUSE) | |
#define set_inuse_bit_at_offset(p, s) \ | |
(chunk_at_offset((p), (s))->size |= PREV_INUSE) | |
#define clear_inuse_bit_at_offset(p, s) \ | |
(chunk_at_offset((p), (s))->size &= ~(PREV_INUSE)) | |
/* | |
Dealing with size fields | |
*/ | |
/* Get size, ignoring use bits */ | |
#define chunksize(p) ((p)->size & ~(SIZE_BITS)) | |
/* Set size at head, without disturbing its use bit */ | |
#define set_head_size(p, s) ((p)->size = (((p)->size & PREV_INUSE) | (s))) | |
/* Set size/use ignoring previous bits in header */ | |
#define set_head(p, s) ((p)->size = (s)) | |
/* Set size at footer (only when chunk is not in use) */ | |
#define set_foot(p, s) (chunk_at_offset(p, s)->prev_size = (s)) | |
/* access macros */ | |
#define bin_at(a, i) BOUNDED_1(_bin_at(a, i)) | |
#define _bin_at(a, i) ((mbinptr)((char*)&(((a)->av)[2*(i)+2]) - 2*SIZE_SZ)) | |
#define init_bin(a, i) ((a)->av[2*(i)+2] = (a)->av[2*(i)+3] = bin_at((a), (i))) | |
#define next_bin(b) ((mbinptr)((char*)(b) + 2 * sizeof(((arena*)0)->av[0]))) | |
#define prev_bin(b) ((mbinptr)((char*)(b) - 2 * sizeof(((arena*)0)->av[0]))) | |
/* | |
The first 2 bins are never indexed. The corresponding av cells are instead | |
used for bookkeeping. This is not to save space, but to simplify | |
indexing, maintain locality, and avoid some initialization tests. | |
*/ | |
#define binblocks(a) (bin_at(a,0)->size)/* bitvector of nonempty blocks */ | |
#define top(a) (bin_at(a,0)->fd) /* The topmost chunk */ | |
#define last_remainder(a) (bin_at(a,1)) /* remainder from last split */ | |
/* | |
Because top initially points to its own bin with initial | |
zero size, thus forcing extension on the first malloc request, | |
we avoid having any special code in malloc to check whether | |
it even exists yet. But we still need to in malloc_extend_top. | |
*/ | |
#define initial_top(a) ((mchunkptr)bin_at(a, 0)) | |
/* field-extraction macros */ | |
#define first(b) ((b)->fd) | |
#define last(b) ((b)->bk) | |
/* | |
Indexing into bins | |
*/ | |
#define bin_index(sz) \ | |
(((((unsigned long)(sz)) >> 9) == 0) ? (((unsigned long)(sz)) >> 3):\ | |
((((unsigned long)(sz)) >> 9) <= 4) ? 56 + (((unsigned long)(sz)) >> 6):\ | |
((((unsigned long)(sz)) >> 9) <= 20) ? 91 + (((unsigned long)(sz)) >> 9):\ | |
((((unsigned long)(sz)) >> 9) <= 84) ? 110 + (((unsigned long)(sz)) >> 12):\ | |
((((unsigned long)(sz)) >> 9) <= 340) ? 119 + (((unsigned long)(sz)) >> 15):\ | |
((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18):\ | |
126) | |
/* | |
bins for chunks < 512 are all spaced 8 bytes apart, and hold | |
identically sized chunks. This is exploited in malloc. | |
*/ | |
#define MAX_SMALLBIN 63 | |
#define MAX_SMALLBIN_SIZE 512 | |
#define SMALLBIN_WIDTH 8 | |
#define smallbin_index(sz) (((unsigned long)(sz)) >> 3) | |
/* | |
Requests are `small' if both the corresponding and the next bin are small | |
*/ | |
#define is_small_request(nb) ((nb) < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH) | |
/* | |
To help compensate for the large number of bins, a one-level index | |
structure is used for bin-by-bin searching. `binblocks' is a | |
one-word bitvector recording whether groups of BINBLOCKWIDTH bins | |
have any (possibly) non-empty bins, so they can be skipped over | |
all at once during during traversals. The bits are NOT always | |
cleared as soon as all bins in a block are empty, but instead only | |
when all are noticed to be empty during traversal in malloc. | |
*/ | |
#define BINBLOCKWIDTH 4 /* bins per block */ | |
/* bin<->block macros */ | |
#define idx2binblock(ix) ((unsigned)1 << ((ix) / BINBLOCKWIDTH)) | |
#define mark_binblock(a, ii) (binblocks(a) |= idx2binblock(ii)) | |
#define clear_binblock(a, ii) (binblocks(a) &= ~(idx2binblock(ii))) | |
/* Static bookkeeping data */ | |
/* Helper macro to initialize bins */ | |
#define IAV(i) _bin_at(&main_arena, i), _bin_at(&main_arena, i) | |
static arena main_arena = { | |
{ | |
0, 0, | |
IAV(0), IAV(1), IAV(2), IAV(3), IAV(4), IAV(5), IAV(6), IAV(7), | |
IAV(8), IAV(9), IAV(10), IAV(11), IAV(12), IAV(13), IAV(14), IAV(15), | |
IAV(16), IAV(17), IAV(18), IAV(19), IAV(20), IAV(21), IAV(22), IAV(23), | |
IAV(24), IAV(25), IAV(26), IAV(27), IAV(28), IAV(29), IAV(30), IAV(31), | |
IAV(32), IAV(33), IAV(34), IAV(35), IAV(36), IAV(37), IAV(38), IAV(39), | |
IAV(40), IAV(41), IAV(42), IAV(43), IAV(44), IAV(45), IAV(46), IAV(47), | |
IAV(48), IAV(49), IAV(50), IAV(51), IAV(52), IAV(53), IAV(54), IAV(55), | |
IAV(56), IAV(57), IAV(58), IAV(59), IAV(60), IAV(61), IAV(62), IAV(63), | |
IAV(64), IAV(65), IAV(66), IAV(67), IAV(68), IAV(69), IAV(70), IAV(71), | |
IAV(72), IAV(73), IAV(74), IAV(75), IAV(76), IAV(77), IAV(78), IAV(79), | |
IAV(80), IAV(81), IAV(82), IAV(83), IAV(84), IAV(85), IAV(86), IAV(87), | |
IAV(88), IAV(89), IAV(90), IAV(91), IAV(92), IAV(93), IAV(94), IAV(95), | |
IAV(96), IAV(97), IAV(98), IAV(99), IAV(100), IAV(101), IAV(102), IAV(103), | |
IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111), | |
IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119), | |
IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127) | |
}, | |
&main_arena, /* next */ | |
0, /* size */ | |
#if THREAD_STATS | |
0, 0, 0, /* stat_lock_direct, stat_lock_loop, stat_lock_wait */ | |
#endif | |
MUTEX_INITIALIZER /* mutex */ | |
}; | |
#undef IAV | |
/* Thread specific data */ | |
static tsd_key_t arena_key; | |
static mutex_t list_lock = MUTEX_INITIALIZER; | |
#if THREAD_STATS | |
static int stat_n_heaps; | |
#define THREAD_STAT(x) x | |
#else | |
#define THREAD_STAT(x) do ; while(0) | |
#endif | |
/* variables holding tunable values */ | |
static unsigned long trim_threshold = DEFAULT_TRIM_THRESHOLD; | |
static unsigned long top_pad = DEFAULT_TOP_PAD; | |
static unsigned int n_mmaps_max = DEFAULT_MMAP_MAX; | |
static unsigned long mmap_threshold = DEFAULT_MMAP_THRESHOLD; | |
static int check_action = DEFAULT_CHECK_ACTION; | |
/* The first value returned from sbrk */ | |
static char* sbrk_base = (char*)(-1); | |
/* The maximum memory obtained from system via sbrk */ | |
static unsigned long max_sbrked_mem; | |
/* The maximum via either sbrk or mmap (too difficult to track with threads) */ | |
#ifdef NO_THREADS | |
static unsigned long max_total_mem; | |
#endif | |
/* The total memory obtained from system via sbrk */ | |
#define sbrked_mem (main_arena.size) | |
/* Tracking mmaps */ | |
static unsigned int n_mmaps; | |
static unsigned int max_n_mmaps; | |
static unsigned long mmapped_mem; | |
static unsigned long max_mmapped_mem; | |
/* Mapped memory in non-main arenas (reliable only for NO_THREADS). */ | |
static unsigned long arena_mem; | |
#ifndef _LIBC | |
#define weak_variable | |
#else | |
/* In GNU libc we want the hook variables to be weak definitions to | |
avoid a problem with Emacs. */ | |
#define weak_variable weak_function | |
#endif | |
/* Already initialized? */ | |
int __malloc_initialized = -1; | |
#ifndef NO_THREADS | |
/* Magic value for the thread-specific arena pointer when | |
malloc_atfork() is in use. */ | |
#define ATFORK_ARENA_PTR ((Void_t*)-1) | |
/* The following two functions are registered via thread_atfork() to | |
make sure that the mutexes remain in a consistent state in the | |
fork()ed version of a thread. Also adapt the malloc and free hooks | |
temporarily, because the `atfork' handler mechanism may use | |
malloc/free internally (e.g. in LinuxThreads). */ | |
#if defined _LIBC || defined MALLOC_HOOKS | |
static __malloc_ptr_t (*save_malloc_hook) __MALLOC_P ((size_t __size, | |
const __malloc_ptr_t)); | |
static void (*save_free_hook) __MALLOC_P ((__malloc_ptr_t __ptr, | |
const __malloc_ptr_t)); | |
static Void_t* save_arena; | |
#endif | |
static void | |
ptmalloc_lock_all __MALLOC_P((void)) | |
{ | |
arena *ar_ptr; | |
(void)mutex_lock(&list_lock); | |
for(ar_ptr = &main_arena;;) { | |
(void)mutex_lock(&ar_ptr->mutex); | |
ar_ptr = ar_ptr->next; | |
if(ar_ptr == &main_arena) break; | |
} | |
#if defined _LIBC || defined MALLOC_HOOKS | |
save_malloc_hook = __malloc_hook; | |
save_free_hook = __free_hook; | |
__malloc_hook = malloc_atfork; | |
__free_hook = free_atfork; | |
/* Only the current thread may perform malloc/free calls now. */ | |
tsd_getspecific(arena_key, save_arena); | |
tsd_setspecific(arena_key, ATFORK_ARENA_PTR); | |
#endif | |
} | |
static void | |
ptmalloc_unlock_all __MALLOC_P((void)) | |
{ | |
arena *ar_ptr; | |
#if defined _LIBC || defined MALLOC_HOOKS | |
tsd_setspecific(arena_key, save_arena); | |
__malloc_hook = save_malloc_hook; | |
__free_hook = save_free_hook; | |
#endif | |
for(ar_ptr = &main_arena;;) { | |
(void)mutex_unlock(&ar_ptr->mutex); | |
ar_ptr = ar_ptr->next; | |
if(ar_ptr == &main_arena) break; | |
} | |
(void)mutex_unlock(&list_lock); | |
} | |
static void | |
ptmalloc_init_all __MALLOC_P((void)) | |
{ | |
arena *ar_ptr; | |
#if defined _LIBC || defined MALLOC_HOOKS | |
tsd_setspecific(arena_key, save_arena); | |
__malloc_hook = save_malloc_hook; | |
__free_hook = save_free_hook; | |
#endif | |
for(ar_ptr = &main_arena;;) { | |
(void)mutex_init(&ar_ptr->mutex); | |
ar_ptr = ar_ptr->next; | |
if(ar_ptr == &main_arena) break; | |
} | |
(void)mutex_init(&list_lock); | |
} | |
#endif /* !defined NO_THREADS */ | |
/* Initialization routine. */ | |
#if defined(_LIBC) | |
#if 0 | |
static void ptmalloc_init __MALLOC_P ((void)) __attribute__ ((constructor)); | |
#endif | |
#ifdef _LIBC | |
#include <string.h> | |
extern char **environ; | |
static char * | |
internal_function | |
next_env_entry (char ***position) | |
{ | |
char **current = *position; | |
char *result = NULL; | |
while (*current != NULL) | |
{ | |
if (__builtin_expect ((*current)[0] == 'M', 0) | |
&& (*current)[1] == 'A' | |
&& (*current)[2] == 'L' | |
&& (*current)[3] == 'L' | |
&& (*current)[4] == 'O' | |
&& (*current)[5] == 'C' | |
&& (*current)[6] == '_') | |
{ | |
result = &(*current)[7]; | |
/* Save current position for next visit. */ | |
*position = ++current; | |
break; | |
} | |
++current; | |
} | |
return result; | |
} | |
#endif | |
static void | |
ptmalloc_init __MALLOC_P((void)) | |
#else | |
void | |
ptmalloc_init __MALLOC_P((void)) | |
#endif | |
{ | |
#if defined _LIBC || defined MALLOC_HOOKS | |
# if __STD_C | |
const char* s; | |
# else | |
char* s; | |
# endif | |
#endif | |
int secure; | |
if(__malloc_initialized >= 0) return; | |
__malloc_initialized = 0; | |
#ifdef _LIBC | |
__libc_pagesize = __getpagesize(); | |
#endif | |
#ifndef NO_THREADS | |
#if defined _LIBC || defined MALLOC_HOOKS | |
/* With some threads implementations, creating thread-specific data | |
or initializing a mutex may call malloc() itself. Provide a | |
simple starter version (realloc() won't work). */ | |
save_malloc_hook = __malloc_hook; | |
save_free_hook = __free_hook; | |
__malloc_hook = malloc_starter; | |
__free_hook = free_starter; | |
#endif | |
#ifdef _LIBC | |
/* Initialize the pthreads interface. */ | |
if (__pthread_initialize != NULL) | |
__pthread_initialize(); | |
#endif | |
#endif /* !defined NO_THREADS */ | |
mutex_init(&main_arena.mutex); | |
mutex_init(&list_lock); | |
tsd_key_create(&arena_key, NULL); | |
tsd_setspecific(arena_key, (Void_t *)&main_arena); | |
thread_atfork(ptmalloc_lock_all, ptmalloc_unlock_all, ptmalloc_init_all); | |
#if defined _LIBC || defined MALLOC_HOOKS | |
#ifndef NO_THREADS | |
__malloc_hook = save_malloc_hook; | |
__free_hook = save_free_hook; | |
#endif | |
secure = __libc_enable_secure; | |
#ifdef _LIBC | |
s = NULL; | |
if (environ != NULL) | |
{ | |
char **runp = environ; | |
char *envline; | |
while (__builtin_expect ((envline = next_env_entry (&runp)) != NULL, 0)) | |
{ | |
size_t len = strcspn (envline, "="); | |
if (envline[len] != '=') | |
/* This is a "MALLOC_" variable at the end of the string | |
without a '=' character. Ignore it since otherwise we | |
will access invalid memory below. */ | |
continue; | |
switch (len) | |
{ | |
case 6: | |
if (memcmp (envline, "CHECK_", 6) == 0) | |
s = &envline[7]; | |
break; | |
case 8: | |
if (! secure && memcmp (envline, "TOP_PAD_", 8) == 0) | |
mALLOPt(M_TOP_PAD, atoi(&envline[9])); | |
break; | |
case 9: | |
if (! secure && memcmp (envline, "MMAP_MAX_", 9) == 0) | |
mALLOPt(M_MMAP_MAX, atoi(&envline[10])); | |
break; | |
case 15: | |
if (! secure) | |
{ | |
if (memcmp (envline, "TRIM_THRESHOLD_", 15) == 0) | |
mALLOPt(M_TRIM_THRESHOLD, atoi(&envline[16])); | |
else if (memcmp (envline, "MMAP_THRESHOLD_", 15) == 0) | |
mALLOPt(M_MMAP_THRESHOLD, atoi(&envline[16])); | |
} | |
break; | |
default: | |
break; | |
} | |
} | |
} | |
#else | |
if (! secure) | |
{ | |
if((s = getenv("MALLOC_TRIM_THRESHOLD_"))) | |
mALLOPt(M_TRIM_THRESHOLD, atoi(s)); | |
if((s = getenv("MALLOC_TOP_PAD_"))) | |
mALLOPt(M_TOP_PAD, atoi(s)); | |
if((s = getenv("MALLOC_MMAP_THRESHOLD_"))) | |
mALLOPt(M_MMAP_THRESHOLD, atoi(s)); | |
if((s = getenv("MALLOC_MMAP_MAX_"))) | |
mALLOPt(M_MMAP_MAX, atoi(s)); | |
} | |
s = getenv("MALLOC_CHECK_"); | |
#endif | |
if(s) { | |
if(s[0]) mALLOPt(M_CHECK_ACTION, (int)(s[0] - '0')); | |
__malloc_check_init(); | |
} | |
if(__malloc_initialize_hook != NULL) | |
(*__malloc_initialize_hook)(); | |
#endif | |
__malloc_initialized = 1; | |
} | |
/* There are platforms (e.g. Hurd) with a link-time hook mechanism. */ | |
#ifdef thread_atfork_static | |
thread_atfork_static(ptmalloc_lock_all, ptmalloc_unlock_all, \ | |
ptmalloc_init_all) | |
#endif | |
#if defined _LIBC || defined MALLOC_HOOKS | |
/* Hooks for debugging versions. The initial hooks just call the | |
initialization routine, then do the normal work. */ | |
static Void_t* | |
#if __STD_C | |
malloc_hook_ini(size_t sz, const __malloc_ptr_t caller) | |
#else | |
malloc_hook_ini(sz, caller) | |
size_t sz; const __malloc_ptr_t caller; | |
#endif | |
{ | |
__malloc_hook = NULL; | |
ptmalloc_init(); | |
return mALLOc(sz); | |
} | |
static Void_t* | |
#if __STD_C | |
realloc_hook_ini(Void_t* ptr, size_t sz, const __malloc_ptr_t caller) | |
#else | |
realloc_hook_ini(ptr, sz, caller) | |
Void_t* ptr; size_t sz; const __malloc_ptr_t caller; | |
#endif | |
{ | |
__malloc_hook = NULL; | |
__realloc_hook = NULL; | |
ptmalloc_init(); | |
return rEALLOc(ptr, sz); | |
} | |
static Void_t* | |
#if __STD_C | |
memalign_hook_ini(size_t alignment, size_t sz, const __malloc_ptr_t caller) | |
#else | |
memalign_hook_ini(alignment, sz, caller) | |
size_t alignment; size_t sz; const __malloc_ptr_t caller; | |
#endif | |
{ | |
__memalign_hook = NULL; | |
ptmalloc_init(); | |
return mEMALIGn(alignment, sz); | |
} | |
void weak_variable (*__malloc_initialize_hook) __MALLOC_P ((void)) = NULL; | |
void weak_variable (*__free_hook) __MALLOC_P ((__malloc_ptr_t __ptr, | |
const __malloc_ptr_t)) = NULL; | |
__malloc_ptr_t weak_variable (*__malloc_hook) | |
__MALLOC_P ((size_t __size, const __malloc_ptr_t)) = malloc_hook_ini; | |
__malloc_ptr_t weak_variable (*__realloc_hook) | |
__MALLOC_P ((__malloc_ptr_t __ptr, size_t __size, const __malloc_ptr_t)) | |
= realloc_hook_ini; | |
__malloc_ptr_t weak_variable (*__memalign_hook) | |
__MALLOC_P ((size_t __alignment, size_t __size, const __malloc_ptr_t)) | |
= memalign_hook_ini; | |
void weak_variable (*__after_morecore_hook) __MALLOC_P ((void)) = NULL; | |
/* Whether we are using malloc checking. */ | |
static int using_malloc_checking; | |
/* A flag that is set by malloc_set_state, to signal that malloc checking | |
must not be enabled on the request from the user (via the MALLOC_CHECK_ | |
environment variable). It is reset by __malloc_check_init to tell | |
malloc_set_state that the user has requested malloc checking. | |
The purpose of this flag is to make sure that malloc checking is not | |
enabled when the heap to be restored was constructed without malloc | |
checking, and thus does not contain the required magic bytes. | |
Otherwise the heap would be corrupted by calls to free and realloc. If | |
it turns out that the heap was created with malloc checking and the | |
user has requested it malloc_set_state just calls __malloc_check_init | |
again to enable it. On the other hand, reusing such a heap without | |
further malloc checking is safe. */ | |
static int disallow_malloc_check; | |
/* Activate a standard set of debugging hooks. */ | |
void | |
__malloc_check_init() | |
{ | |
if (disallow_malloc_check) { | |
disallow_malloc_check = 0; | |
return; | |
} | |
using_malloc_checking = 1; | |
__malloc_hook = malloc_check; | |
__free_hook = free_check; | |
__realloc_hook = realloc_check; | |
__memalign_hook = memalign_check; | |
if(check_action & 1) | |
fprintf(stderr, "malloc: using debugging hooks\n"); | |
} | |
#endif | |
/* Routines dealing with mmap(). */ | |
#if HAVE_MMAP | |
#ifndef MAP_ANONYMOUS | |
static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */ | |
#define MMAP(addr, size, prot, flags) ((dev_zero_fd < 0) ? \ | |
(dev_zero_fd = open("/dev/zero", O_RDWR), \ | |
mmap((addr), (size), (prot), (flags), dev_zero_fd, 0)) : \ | |
mmap((addr), (size), (prot), (flags), dev_zero_fd, 0)) | |
#else | |
#define MMAP(addr, size, prot, flags) \ | |
(mmap((addr), (size), (prot), (flags)|MAP_ANONYMOUS, -1, 0)) | |
#endif | |
#if defined __GNUC__ && __GNUC__ >= 2 | |
/* This function is only called from one place, inline it. */ | |
__inline__ | |
#endif | |
static mchunkptr | |
internal_function | |
#if __STD_C | |
mmap_chunk(size_t size) | |
#else | |
mmap_chunk(size) size_t size; | |
#endif | |
{ | |
size_t page_mask = malloc_getpagesize - 1; | |
mchunkptr p; | |
/* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because | |
* there is no following chunk whose prev_size field could be used. | |
*/ | |
size = (size + SIZE_SZ + page_mask) & ~page_mask; | |
p = (mchunkptr)MMAP(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE); | |
if(p == (mchunkptr) MAP_FAILED) return 0; | |
n_mmaps++; | |
if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps; | |
/* We demand that eight bytes into a page must be 8-byte aligned. */ | |
assert(aligned_OK(chunk2mem(p))); | |
/* The offset to the start of the mmapped region is stored | |
* in the prev_size field of the chunk; normally it is zero, | |
* but that can be changed in memalign(). | |
*/ | |
p->prev_size = 0; | |
set_head(p, size|IS_MMAPPED); | |
mmapped_mem += size; | |
if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) | |
max_mmapped_mem = mmapped_mem; | |
#ifdef NO_THREADS | |
if ((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem) | |
max_total_mem = mmapped_mem + arena_mem + sbrked_mem; | |
#endif | |
return p; | |
} | |
static void | |
internal_function | |
#if __STD_C | |
munmap_chunk(mchunkptr p) | |
#else | |
munmap_chunk(p) mchunkptr p; | |
#endif | |
{ | |
INTERNAL_SIZE_T size = chunksize(p); | |
int ret; | |
assert (chunk_is_mmapped(p)); | |
assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem)); | |
assert((n_mmaps > 0)); | |
assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0); | |
n_mmaps--; | |
mmapped_mem -= (size + p->prev_size); | |
ret = munmap((char *)p - p->prev_size, size + p->prev_size); | |
/* munmap returns non-zero on failure */ | |
assert(ret == 0); | |
} | |
#if HAVE_MREMAP | |
static mchunkptr | |
internal_function | |
#if __STD_C | |
mremap_chunk(mchunkptr p, size_t new_size) | |
#else | |
mremap_chunk(p, new_size) mchunkptr p; size_t new_size; | |
#endif | |
{ | |
size_t page_mask = malloc_getpagesize - 1; | |
INTERNAL_SIZE_T offset = p->prev_size; | |
INTERNAL_SIZE_T size = chunksize(p); | |
char *cp; | |
assert (chunk_is_mmapped(p)); | |
assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem)); | |
assert((n_mmaps > 0)); | |
assert(((size + offset) & (malloc_getpagesize-1)) == 0); | |
/* Note the extra SIZE_SZ overhead as in mmap_chunk(). */ | |
new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask; | |
cp = (char *)mremap((char *)p - offset, size + offset, new_size, | |
MREMAP_MAYMOVE); | |
if (cp == MAP_FAILED) return 0; | |
p = (mchunkptr)(cp + offset); | |
assert(aligned_OK(chunk2mem(p))); | |
assert((p->prev_size == offset)); | |
set_head(p, (new_size - offset)|IS_MMAPPED); | |
mmapped_mem -= size + offset; | |
mmapped_mem += new_size; | |
if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) | |
max_mmapped_mem = mmapped_mem; | |
#ifdef NO_THREADS | |
if ((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem) | |
max_total_mem = mmapped_mem + arena_mem + sbrked_mem; | |
#endif | |
return p; | |
} | |
#endif /* HAVE_MREMAP */ | |
#endif /* HAVE_MMAP */ | |
/* Managing heaps and arenas (for concurrent threads) */ | |
#if USE_ARENAS | |
/* Create a new heap. size is automatically rounded up to a multiple | |
of the page size. */ | |
static heap_info * | |
internal_function | |
#if __STD_C | |
new_heap(size_t size) | |
#else | |
new_heap(size) size_t size; | |
#endif | |
{ | |
size_t page_mask = malloc_getpagesize - 1; | |
char *p1, *p2; | |
unsigned long ul; | |
heap_info *h; | |
if(size+top_pad < HEAP_MIN_SIZE) | |
size = HEAP_MIN_SIZE; | |
else if(size+top_pad <= HEAP_MAX_SIZE) | |
size += top_pad; | |
else if(size > HEAP_MAX_SIZE) | |
return 0; | |
else | |
size = HEAP_MAX_SIZE; | |
size = (size + page_mask) & ~page_mask; | |
/* A memory region aligned to a multiple of HEAP_MAX_SIZE is needed. | |
No swap space needs to be reserved for the following large | |
mapping (on Linux, this is the case for all non-writable mappings | |
anyway). */ | |
p1 = (char *)MMAP(0, HEAP_MAX_SIZE<<1, PROT_NONE, MAP_PRIVATE|MAP_NORESERVE); | |
if(p1 != MAP_FAILED) { | |
p2 = (char *)(((unsigned long)p1 + (HEAP_MAX_SIZE-1)) & ~(HEAP_MAX_SIZE-1)); | |
ul = p2 - p1; | |
if (ul) | |
munmap(p1, ul); | |
munmap(p2 + HEAP_MAX_SIZE, HEAP_MAX_SIZE - ul); | |
} else { | |
/* Try to take the chance that an allocation of only HEAP_MAX_SIZE | |
is already aligned. */ | |
p2 = (char *)MMAP(0, HEAP_MAX_SIZE, PROT_NONE, MAP_PRIVATE|MAP_NORESERVE); | |
if(p2 == MAP_FAILED) | |
return 0; | |
if((unsigned long)p2 & (HEAP_MAX_SIZE-1)) { | |
munmap(p2, HEAP_MAX_SIZE); | |
return 0; | |
} | |
} | |
if(MMAP(p2, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED) | |
== (char *) MAP_FAILED) { | |
munmap(p2, HEAP_MAX_SIZE); | |
return 0; | |
} | |
h = (heap_info *)p2; | |
h->size = size; | |
THREAD_STAT(stat_n_heaps++); | |
return h; | |
} | |
/* Grow or shrink a heap. size is automatically rounded up to a | |
multiple of the page size if it is positive. */ | |
static int | |
#if __STD_C | |
grow_heap(heap_info *h, long diff) | |
#else | |
grow_heap(h, diff) heap_info *h; long diff; | |
#endif | |
{ | |
size_t page_mask = malloc_getpagesize - 1; | |
long new_size; | |
if(diff >= 0) { | |
diff = (diff + page_mask) & ~page_mask; | |
new_size = (long)h->size + diff; | |
if(new_size > HEAP_MAX_SIZE) | |
return -1; | |
if(MMAP((char *)h + h->size, diff, PROT_READ|PROT_WRITE, | |
MAP_PRIVATE|MAP_FIXED) == (char *) MAP_FAILED) | |
return -2; | |
} else { | |
new_size = (long)h->size + diff; | |
if(new_size < (long)sizeof(*h)) | |
return -1; | |
/* Try to re-map the extra heap space freshly to save memory, and | |
make it inaccessible. */ | |
if((char *)MMAP((char *)h + new_size, -diff, PROT_NONE, | |
MAP_PRIVATE|MAP_FIXED) == (char *) MAP_FAILED) | |
return -2; | |
} | |
h->size = new_size; | |
return 0; | |
} | |
/* Delete a heap. */ | |
#define delete_heap(heap) munmap((char*)(heap), HEAP_MAX_SIZE) | |
/* arena_get() acquires an arena and locks the corresponding mutex. | |
First, try the one last locked successfully by this thread. (This | |
is the common case and handled with a macro for speed.) Then, loop | |
once over the circularly linked list of arenas. If no arena is | |
readily available, create a new one. In this latter case, `size' | |
is just a hint as to how much memory will be required immediately | |
in the new arena. */ | |
#define arena_get(ptr, size) do { \ | |
Void_t *vptr = NULL; \ | |
ptr = (arena *)tsd_getspecific(arena_key, vptr); \ | |
if(ptr && !mutex_trylock(&ptr->mutex)) { \ | |
THREAD_STAT(++(ptr->stat_lock_direct)); \ | |
} else \ | |
ptr = arena_get2(ptr, (size)); \ | |
} while(0) | |
static arena * | |
internal_function | |
#if __STD_C | |
arena_get2(arena *a_tsd, size_t size) | |
#else | |
arena_get2(a_tsd, size) arena *a_tsd; size_t size; | |
#endif | |
{ | |
arena *a; | |
heap_info *h; | |
char *ptr; | |
int i; | |
unsigned long misalign; | |
if(!a_tsd) | |
a = a_tsd = &main_arena; | |
else { | |
a = a_tsd->next; | |
if(!a) { | |
/* This can only happen while initializing the new arena. */ | |
(void)mutex_lock(&main_arena.mutex); | |
THREAD_STAT(++(main_arena.stat_lock_wait)); | |
return &main_arena; | |
} | |
} | |
/* Check the global, circularly linked list for available arenas. */ | |
repeat: | |
do { | |
if(!mutex_trylock(&a->mutex)) { | |
THREAD_STAT(++(a->stat_lock_loop)); | |
tsd_setspecific(arena_key, (Void_t *)a); | |
return a; | |
} | |
a = a->next; | |
} while(a != a_tsd); | |
/* If not even the list_lock can be obtained, try again. This can | |
happen during `atfork', or for example on systems where thread | |
creation makes it temporarily impossible to obtain _any_ | |
locks. */ | |
if(mutex_trylock(&list_lock)) { | |
a = a_tsd; | |
goto repeat; | |
} | |
(void)mutex_unlock(&list_lock); | |
/* Nothing immediately available, so generate a new arena. */ | |
h = new_heap(size + (sizeof(*h) + sizeof(*a) + MALLOC_ALIGNMENT)); | |
if(!h) { | |
/* Maybe size is too large to fit in a single heap. So, just try | |
to create a minimally-sized arena and let chunk_alloc() attempt | |
to deal with the large request via mmap_chunk(). */ | |
h = new_heap(sizeof(*h) + sizeof(*a) + MALLOC_ALIGNMENT); | |
if(!h) | |
return 0; | |
} | |
a = h->ar_ptr = (arena *)(h+1); | |
for(i=0; i<NAV; i++) | |
init_bin(a, i); | |
a->next = NULL; | |
a->size = h->size; | |
arena_mem += h->size; | |
#ifdef NO_THREADS | |
if((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem) | |
max_total_mem = mmapped_mem + arena_mem + sbrked_mem; | |
#endif | |
tsd_setspecific(arena_key, (Void_t *)a); | |
mutex_init(&a->mutex); | |
i = mutex_lock(&a->mutex); /* remember result */ | |
/* Set up the top chunk, with proper alignment. */ | |
ptr = (char *)(a + 1); | |
misalign = (unsigned long)chunk2mem(ptr) & MALLOC_ALIGN_MASK; | |
if (misalign > 0) | |
ptr += MALLOC_ALIGNMENT - misalign; | |
top(a) = (mchunkptr)ptr; | |
set_head(top(a), (((char*)h + h->size) - ptr) | PREV_INUSE); | |
/* Add the new arena to the list. */ | |
(void)mutex_lock(&list_lock); | |
a->next = main_arena.next; | |
main_arena.next = a; | |
(void)mutex_unlock(&list_lock); | |
if(i) /* locking failed; keep arena for further attempts later */ | |
return 0; | |
THREAD_STAT(++(a->stat_lock_loop)); | |
return a; | |
} | |
/* find the heap and corresponding arena for a given ptr */ | |
#define heap_for_ptr(ptr) \ | |
((heap_info *)((unsigned long)(ptr) & ~(HEAP_MAX_SIZE-1))) | |
#define arena_for_ptr(ptr) \ | |
(((mchunkptr)(ptr) < top(&main_arena) && (char *)(ptr) >= sbrk_base) ? \ | |
&main_arena : heap_for_ptr(ptr)->ar_ptr) | |
#else /* !USE_ARENAS */ | |
/* There is only one arena, main_arena. */ | |
#define arena_get(ptr, sz) (ptr = &main_arena) | |
#define arena_for_ptr(ptr) (&main_arena) | |
#endif /* USE_ARENAS */ | |
/* | |
Debugging support | |
*/ | |
#if MALLOC_DEBUG | |
/* | |
These routines make a number of assertions about the states | |
of data structures that should be true at all times. If any | |
are not true, it's very likely that a user program has somehow | |
trashed memory. (It's also possible that there is a coding error | |
in malloc. In which case, please report it!) | |
*/ | |
#if __STD_C | |
static void do_check_chunk(arena *ar_ptr, mchunkptr p) | |
#else | |
static void do_check_chunk(ar_ptr, p) arena *ar_ptr; mchunkptr p; | |
#endif | |
{ | |
INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; | |
/* No checkable chunk is mmapped */ | |
assert(!chunk_is_mmapped(p)); | |
#if USE_ARENAS | |
if(ar_ptr != &main_arena) { | |
heap_info *heap = heap_for_ptr(p); | |
assert(heap->ar_ptr == ar_ptr); | |
if(p != top(ar_ptr)) | |
assert((char *)p + sz <= (char *)heap + heap->size); | |
else | |
assert((char *)p + sz == (char *)heap + heap->size); | |
return; | |
} | |
#endif | |
/* Check for legal address ... */ | |
assert((char*)p >= sbrk_base); | |
if (p != top(ar_ptr)) | |
assert((char*)p + sz <= (char*)top(ar_ptr)); | |
else | |
assert((char*)p + sz <= sbrk_base + sbrked_mem); | |
} | |
#if __STD_C | |
static void do_check_free_chunk(arena *ar_ptr, mchunkptr p) | |
#else | |
static void do_check_free_chunk(ar_ptr, p) arena *ar_ptr; mchunkptr p; | |
#endif | |
{ | |
INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; | |
mchunkptr next = chunk_at_offset(p, sz); | |
do_check_chunk(ar_ptr, p); | |
/* Check whether it claims to be free ... */ | |
assert(!inuse(p)); | |
/* Must have OK size and fields */ | |
assert((long)sz >= (long)MINSIZE); | |
assert((sz & MALLOC_ALIGN_MASK) == 0); | |
assert(aligned_OK(chunk2mem(p))); | |
/* ... matching footer field */ | |
assert(next->prev_size == sz); | |
/* ... and is fully consolidated */ | |
assert(prev_inuse(p)); | |
assert (next == top(ar_ptr) || inuse(next)); | |
/* ... and has minimally sane links */ | |
assert(p->fd->bk == p); | |
assert(p->bk->fd == p); | |
} | |
#if __STD_C | |
static void do_check_inuse_chunk(arena *ar_ptr, mchunkptr p) | |
#else | |
static void do_check_inuse_chunk(ar_ptr, p) arena *ar_ptr; mchunkptr p; | |
#endif | |
{ | |
mchunkptr next = next_chunk(p); | |
do_check_chunk(ar_ptr, p); | |
/* Check whether it claims to be in use ... */ | |
assert(inuse(p)); | |
/* ... whether its size is OK (it might be a fencepost) ... */ | |
assert(chunksize(p) >= MINSIZE || next->size == (0|PREV_INUSE)); | |
/* ... and is surrounded by OK chunks. | |
Since more things can be checked with free chunks than inuse ones, | |
if an inuse chunk borders them and debug is on, it's worth doing them. | |
*/ | |
if (!prev_inuse(p)) | |
{ | |
mchunkptr prv = prev_chunk(p); | |
assert(next_chunk(prv) == p); | |
do_check_free_chunk(ar_ptr, prv); | |
} | |
if (next == top(ar_ptr)) | |
{ | |
assert(prev_inuse(next)); | |
assert(chunksize(next) >= MINSIZE); | |
} | |
else if (!inuse(next)) | |
do_check_free_chunk(ar_ptr, next); | |
} | |
#if __STD_C | |
static void do_check_malloced_chunk(arena *ar_ptr, | |
mchunkptr p, INTERNAL_SIZE_T s) | |
#else | |
static void do_check_malloced_chunk(ar_ptr, p, s) | |
arena *ar_ptr; mchunkptr p; INTERNAL_SIZE_T s; | |
#endif | |
{ | |
INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; | |
long room = sz - s; | |
do_check_inuse_chunk(ar_ptr, p); | |
/* Legal size ... */ | |
assert((long)sz >= (long)MINSIZE); | |
assert((sz & MALLOC_ALIGN_MASK) == 0); | |
assert(room >= 0); | |
assert(room < (long)MINSIZE); | |
/* ... and alignment */ | |
assert(aligned_OK(chunk2mem(p))); | |
/* ... and was allocated at front of an available chunk */ | |
assert(prev_inuse(p)); | |
} | |
#define check_free_chunk(A,P) do_check_free_chunk(A,P) | |
#define check_inuse_chunk(A,P) do_check_inuse_chunk(A,P) | |
#define check_chunk(A,P) do_check_chunk(A,P) | |
#define check_malloced_chunk(A,P,N) do_check_malloced_chunk(A,P,N) | |
#else | |
#define check_free_chunk(A,P) | |
#define check_inuse_chunk(A,P) | |
#define check_chunk(A,P) | |
#define check_malloced_chunk(A,P,N) | |
#endif | |
/* | |
Macro-based internal utilities | |
*/ | |
/* | |
Linking chunks in bin lists. | |
Call these only with variables, not arbitrary expressions, as arguments. | |
*/ | |
/* | |
Place chunk p of size s in its bin, in size order, | |
putting it ahead of others of same size. | |
*/ | |
#define frontlink(A, P, S, IDX, BK, FD) \ | |
{ \ | |
if (S < MAX_SMALLBIN_SIZE) \ | |
{ \ | |
IDX = smallbin_index(S); \ | |
mark_binblock(A, IDX); \ | |
BK = bin_at(A, IDX); \ | |
FD = BK->fd; \ | |
P->bk = BK; \ | |
P->fd = FD; \ | |
FD->bk = BK->fd = P; \ | |
} \ | |
else \ | |
{ \ | |
IDX = bin_index(S); \ | |
BK = bin_at(A, IDX); \ | |
FD = BK->fd; \ | |
if (FD == BK) mark_binblock(A, IDX); \ | |
else \ | |
{ \ | |
while (FD != BK && S < chunksize(FD)) FD = FD->fd; \ | |
BK = FD->bk; \ | |
} \ | |
P->bk = BK; \ | |
P->fd = FD; \ | |
FD->bk = BK->fd = P; \ | |
} \ | |
} | |
/* take a chunk off a list */ | |
#define unlink(P, BK, FD) \ | |
{ \ | |
BK = P->bk; \ | |
FD = P->fd; \ | |
FD->bk = BK; \ | |
BK->fd = FD; \ | |
} \ | |
/* Place p as the last remainder */ | |
#define link_last_remainder(A, P) \ | |
{ \ | |
last_remainder(A)->fd = last_remainder(A)->bk = P; \ | |
P->fd = P->bk = last_remainder(A); \ | |
} | |
/* Clear the last_remainder bin */ | |
#define clear_last_remainder(A) \ | |
(last_remainder(A)->fd = last_remainder(A)->bk = last_remainder(A)) | |
/* | |
Extend the top-most chunk by obtaining memory from system. | |
Main interface to sbrk (but see also malloc_trim). | |
*/ | |
#if defined __GNUC__ && __GNUC__ >= 2 | |
/* This function is called only from one place, inline it. */ | |
__inline__ | |
#endif | |
static void | |
internal_function | |
#if __STD_C | |
malloc_extend_top(arena *ar_ptr, INTERNAL_SIZE_T nb) | |
#else | |
malloc_extend_top(ar_ptr, nb) arena *ar_ptr; INTERNAL_SIZE_T nb; | |
#endif | |
{ | |
unsigned long pagesz = malloc_getpagesize; | |
mchunkptr old_top = top(ar_ptr); /* Record state of old top */ | |
INTERNAL_SIZE_T old_top_size = chunksize(old_top); | |
INTERNAL_SIZE_T top_size; /* new size of top chunk */ | |
#if USE_ARENAS | |
if(ar_ptr == &main_arena) { | |
#endif | |
char* brk; /* return value from sbrk */ | |
INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */ | |
INTERNAL_SIZE_T correction; /* bytes for 2nd sbrk call */ | |
char* new_brk; /* return of 2nd sbrk call */ | |
char* old_end = (char*)(chunk_at_offset(old_top, old_top_size)); | |
/* Pad request with top_pad plus minimal overhead */ | |
INTERNAL_SIZE_T sbrk_size = nb + top_pad + MINSIZE; | |
/* If not the first time through, round to preserve page boundary */ | |
/* Otherwise, we need to correct to a page size below anyway. */ | |
/* (We also correct below if an intervening foreign sbrk call.) */ | |
if (sbrk_base != (char*)(-1)) | |
sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1); | |
brk = (char*)(MORECORE (sbrk_size)); | |
/* Fail if sbrk failed or if a foreign sbrk call killed our space */ | |
if (brk == (char*)(MORECORE_FAILURE) || | |
(brk < old_end && old_top != initial_top(&main_arena))) | |
return; | |
#if defined _LIBC || defined MALLOC_HOOKS | |
/* Call the `morecore' hook if necessary. */ | |
if (__after_morecore_hook) | |
(*__after_morecore_hook) (); | |
#endif | |
sbrked_mem += sbrk_size; | |
if (brk == old_end) { /* can just add bytes to current top */ | |
top_size = sbrk_size + old_top_size; | |
set_head(old_top, top_size | PREV_INUSE); | |
old_top = 0; /* don't free below */ | |
} else { | |
if (sbrk_base == (char*)(-1)) /* First time through. Record base */ | |
sbrk_base = brk; | |
else | |
/* Someone else called sbrk(). Count those bytes as sbrked_mem. */ | |
sbrked_mem += brk - (char*)old_end; | |
/* Guarantee alignment of first new chunk made from this space */ | |
front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK; | |
if (front_misalign > 0) { | |
correction = (MALLOC_ALIGNMENT) - front_misalign; | |
brk += correction; | |
} else | |
correction = 0; | |
/* Guarantee the next brk will be at a page boundary */ | |
correction += pagesz - ((unsigned long)(brk + sbrk_size) & (pagesz - 1)); | |
/* Allocate correction */ | |
new_brk = (char*)(MORECORE (correction)); | |
if (new_brk == (char*)(MORECORE_FAILURE)) return; | |
#if defined _LIBC || defined MALLOC_HOOKS | |
/* Call the `morecore' hook if necessary. */ | |
if (__after_morecore_hook) | |
(*__after_morecore_hook) (); | |
#endif | |
sbrked_mem += correction; | |
top(&main_arena) = chunk_at_offset(brk, 0); | |
top_size = new_brk - brk + correction; | |
set_head(top(&main_arena), top_size | PREV_INUSE); | |
if (old_top == initial_top(&main_arena)) | |
old_top = 0; /* don't free below */ | |
} | |
if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem) | |
max_sbrked_mem = sbrked_mem; | |
#ifdef NO_THREADS | |
if ((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem) | |
max_total_mem = mmapped_mem + arena_mem + sbrked_mem; | |
#endif | |
#if USE_ARENAS | |
} else { /* ar_ptr != &main_arena */ | |
heap_info *old_heap, *heap; | |
size_t old_heap_size; | |
if(old_top_size < MINSIZE) /* this should never happen */ | |
return; | |
/* First try to extend the current heap. */ | |
if(MINSIZE + nb <= old_top_size) | |
return; | |
old_heap = heap_for_ptr(old_top); | |
old_heap_size = old_heap->size; | |
if(grow_heap(old_heap, MINSIZE + nb - old_top_size) == 0) { | |
ar_ptr->size += old_heap->size - old_heap_size; | |
arena_mem += old_heap->size - old_heap_size; | |
#ifdef NO_THREADS | |
if(mmapped_mem + arena_mem + sbrked_mem > max_total_mem) | |
max_total_mem = mmapped_mem + arena_mem + sbrked_mem; | |
#endif | |
top_size = ((char *)old_heap + old_heap->size) - (char *)old_top; | |
set_head(old_top, top_size | PREV_INUSE); | |
return; | |
} | |
/* A new heap must be created. */ | |
heap = new_heap(nb + (MINSIZE + sizeof(*heap))); | |
if(!heap) | |
return; | |
heap->ar_ptr = ar_ptr; | |
heap->prev = old_heap; | |
ar_ptr->size += heap->size; | |
arena_mem += heap->size; | |
#ifdef NO_THREADS | |
if((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem) | |
max_total_mem = mmapped_mem + arena_mem + sbrked_mem; | |
#endif | |
/* Set up the new top, so we can safely use chunk_free() below. */ | |
top(ar_ptr) = chunk_at_offset(heap, sizeof(*heap)); | |
top_size = heap->size - sizeof(*heap); | |
set_head(top(ar_ptr), top_size | PREV_INUSE); | |
} | |
#endif /* USE_ARENAS */ | |
/* We always land on a page boundary */ | |
assert(((unsigned long)((char*)top(ar_ptr) + top_size) & (pagesz-1)) == 0); | |
/* Setup fencepost and free the old top chunk. */ | |
if(old_top) { | |
/* The fencepost takes at least MINSIZE bytes, because it might | |
become the top chunk again later. Note that a footer is set | |
up, too, although the chunk is marked in use. */ | |
old_top_size -= MINSIZE; | |
set_head(chunk_at_offset(old_top, old_top_size + 2*SIZE_SZ), 0|PREV_INUSE); | |
if(old_top_size >= MINSIZE) { | |
set_head(chunk_at_offset(old_top, old_top_size), (2*SIZE_SZ)|PREV_INUSE); | |
set_foot(chunk_at_offset(old_top, old_top_size), (2*SIZE_SZ)); | |
set_head_size(old_top, old_top_size); | |
chunk_free(ar_ptr, old_top); | |
} else { | |
set_head(old_top, (old_top_size + 2*SIZE_SZ)|PREV_INUSE); | |
set_foot(old_top, (old_top_size + 2*SIZE_SZ)); | |
} | |
} | |
} | |
/* Main public routines */ | |
/* | |
Malloc Algorithm: | |
The requested size is first converted into a usable form, `nb'. | |
This currently means to add 4 bytes overhead plus possibly more to | |
obtain 8-byte alignment and/or to obtain a size of at least | |
MINSIZE (currently 16, 24, or 32 bytes), the smallest allocatable | |
size. (All fits are considered `exact' if they are within MINSIZE | |
bytes.) | |
From there, the first successful of the following steps is taken: | |
1. The bin corresponding to the request size is scanned, and if | |
a chunk of exactly the right size is found, it is taken. | |
2. The most recently remaindered chunk is used if it is big | |
enough. This is a form of (roving) first fit, used only in | |
the absence of exact fits. Runs of consecutive requests use | |
the remainder of the chunk used for the previous such request | |
whenever possible. This limited use of a first-fit style | |
allocation strategy tends to give contiguous chunks | |
coextensive lifetimes, which improves locality and can reduce | |
fragmentation in the long run. | |
3. Other bins are scanned in increasing size order, using a | |
chunk big enough to fulfill the request, and splitting off | |
any remainder. This search is strictly by best-fit; i.e., | |
the smallest (with ties going to approximately the least | |
recently used) chunk that fits is selected. | |
4. If large enough, the chunk bordering the end of memory | |
(`top') is split off. (This use of `top' is in accord with | |
the best-fit search rule. In effect, `top' is treated as | |
larger (and thus less well fitting) than any other available | |
chunk since it can be extended to be as large as necessary | |
(up to system limitations). | |
5. If the request size meets the mmap threshold and the | |
system supports mmap, and there are few enough currently | |
allocated mmapped regions, and a call to mmap succeeds, | |
the request is allocated via direct memory mapping. | |
6. Otherwise, the top of memory is extended by | |
obtaining more space from the system (normally using sbrk, | |
but definable to anything else via the MORECORE macro). | |
Memory is gathered from the system (in system page-sized | |
units) in a way that allows chunks obtained across different | |
sbrk calls to be consolidated, but does not require | |
contiguous memory. Thus, it should be safe to intersperse | |
mallocs with other sbrk calls. | |
All allocations are made from the `lowest' part of any found | |
chunk. (The implementation invariant is that prev_inuse is | |
always true of any allocated chunk; i.e., that each allocated | |
chunk borders either a previously allocated and still in-use chunk, | |
or the base of its memory arena.) | |
*/ | |
#if __STD_C | |
Void_t* mALLOc(size_t bytes) | |
#else | |
Void_t* mALLOc(bytes) size_t bytes; | |
#endif | |
{ | |
arena *ar_ptr; | |
INTERNAL_SIZE_T nb; /* padded request size */ | |
mchunkptr victim; | |
#if defined _LIBC || defined MALLOC_HOOKS | |
__malloc_ptr_t (*hook) __MALLOC_PMT ((size_t, __const __malloc_ptr_t)) = | |
__malloc_hook; | |
if (hook != NULL) { | |
Void_t* result; | |
#if defined __GNUC__ && __GNUC__ >= 2 | |
result = (*hook)(bytes, RETURN_ADDRESS (0)); | |
#else | |
result = (*hook)(bytes, NULL); | |
#endif | |
return result; | |
} | |
#endif | |
if(request2size(bytes, nb)) | |
return 0; | |
arena_get(ar_ptr, nb); | |
if(!ar_ptr) | |
return 0; | |
victim = chunk_alloc(ar_ptr, nb); | |
if(!victim) { | |
/* Maybe the failure is due to running out of mmapped areas. */ | |
if(ar_ptr != &main_arena) { | |
(void)mutex_unlock(&ar_ptr->mutex); | |
(void)mutex_lock(&main_arena.mutex); | |
victim = chunk_alloc(&main_arena, nb); | |
(void)mutex_unlock(&main_arena.mutex); | |
} else { | |
#if USE_ARENAS | |
/* ... or sbrk() has failed and there is still a chance to mmap() */ | |
ar_ptr = arena_get2(ar_ptr->next ? ar_ptr : 0, nb); | |
(void)mutex_unlock(&main_arena.mutex); | |
if(ar_ptr) { | |
victim = chunk_alloc(ar_ptr, nb); | |
(void)mutex_unlock(&ar_ptr->mutex); | |
} | |
#endif | |
} | |
if(!victim) return 0; | |
} else | |
(void)mutex_unlock(&ar_ptr->mutex); | |
return BOUNDED_N(chunk2mem(victim), bytes); | |
} | |
static mchunkptr | |
internal_function | |
#if __STD_C | |
chunk_alloc(arena *ar_ptr, INTERNAL_SIZE_T nb) | |
#else | |
chunk_alloc(ar_ptr, nb) arena *ar_ptr; INTERNAL_SIZE_T nb; | |
#endif | |
{ | |
mchunkptr victim; /* inspected/selected chunk */ | |
INTERNAL_SIZE_T victim_size; /* its size */ | |
int idx; /* index for bin traversal */ | |
mbinptr bin; /* associated bin */ | |
mchunkptr remainder; /* remainder from a split */ | |
long remainder_size; /* its size */ | |
int remainder_index; /* its bin index */ | |
unsigned long block; /* block traverser bit */ | |
int startidx; /* first bin of a traversed block */ | |
mchunkptr fwd; /* misc temp for linking */ | |
mchunkptr bck; /* misc temp for linking */ | |
mbinptr q; /* misc temp */ | |
/* Check for exact match in a bin */ | |
if (is_small_request(nb)) /* Faster version for small requests */ | |
{ | |
idx = smallbin_index(nb); | |
/* No traversal or size check necessary for small bins. */ | |
q = _bin_at(ar_ptr, idx); | |
victim = last(q); | |
/* Also scan the next one, since it would have a remainder < MINSIZE */ | |
if (victim == q) | |
{ | |
q = next_bin(q); | |
victim = last(q); | |
} | |
if (victim != q) | |
{ | |
victim_size = chunksize(victim); | |
unlink(victim, bck, fwd); | |
set_inuse_bit_at_offset(victim, victim_size); | |
check_malloced_chunk(ar_ptr, victim, nb); | |
return victim; | |
} | |
idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */ | |
} | |
else | |
{ | |
idx = bin_index(nb); | |
bin = bin_at(ar_ptr, idx); | |
for (victim = last(bin); victim != bin; victim = victim->bk) | |
{ | |
victim_size = chunksize(victim); | |
remainder_size = victim_size - nb; | |
if (remainder_size >= (long)MINSIZE) /* too big */ | |
{ | |
--idx; /* adjust to rescan below after checking last remainder */ | |
break; | |
} | |
else if (remainder_size >= 0) /* exact fit */ | |
{ | |
unlink(victim, bck, fwd); | |
set_inuse_bit_at_offset(victim, victim_size); | |
check_malloced_chunk(ar_ptr, victim, nb); | |
return victim; | |
} | |
} | |
++idx; | |
} | |
/* Try to use the last split-off remainder */ | |
if ( (victim = last_remainder(ar_ptr)->fd) != last_remainder(ar_ptr)) | |
{ | |
victim_size = chunksize(victim); | |
remainder_size = victim_size - nb; | |
if (remainder_size >= (long)MINSIZE) /* re-split */ | |
{ | |
remainder = chunk_at_offset(victim, nb); | |
set_head(victim, nb | PREV_INUSE); | |
link_last_remainder(ar_ptr, remainder); | |
set_head(remainder, remainder_size | PREV_INUSE); | |
set_foot(remainder, remainder_size); | |
check_malloced_chunk(ar_ptr, victim, nb); | |
return victim; | |
} | |
clear_last_remainder(ar_ptr); | |
if (remainder_size >= 0) /* exhaust */ | |
{ | |
set_inuse_bit_at_offset(victim, victim_size); | |
check_malloced_chunk(ar_ptr, victim, nb); | |
return victim; | |
} | |
/* Else place in bin */ | |
frontlink(ar_ptr, victim, victim_size, remainder_index, bck, fwd); | |
} | |
/* | |
If there are any possibly nonempty big-enough blocks, | |
search for best fitting chunk by scanning bins in blockwidth units. | |
*/ | |
if ( (block = idx2binblock(idx)) <= binblocks(ar_ptr)) | |
{ | |
/* Get to the first marked block */ | |
if ( (block & binblocks(ar_ptr)) == 0) | |
{ | |
/* force to an even block boundary */ | |
idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH; | |
block <<= 1; | |
while ((block & binblocks(ar_ptr)) == 0) | |
{ | |
idx += BINBLOCKWIDTH; | |
block <<= 1; | |
} | |
} | |
/* For each possibly nonempty block ... */ | |
for (;;) | |
{ | |
startidx = idx; /* (track incomplete blocks) */ | |
q = bin = _bin_at(ar_ptr, idx); | |
/* For each bin in this block ... */ | |
do | |
{ | |
/* Find and use first big enough chunk ... */ | |
for (victim = last(bin); victim != bin; victim = victim->bk) | |
{ | |
victim_size = chunksize(victim); | |
remainder_size = victim_size - nb; | |
if (remainder_size >= (long)MINSIZE) /* split */ | |
{ | |
remainder = chunk_at_offset(victim, nb); | |
set_head(victim, nb | PREV_INUSE); | |
unlink(victim, bck, fwd); | |
link_last_remainder(ar_ptr, remainder); | |
set_head(remainder, remainder_size | PREV_INUSE); | |
set_foot(remainder, remainder_size); | |
check_malloced_chunk(ar_ptr, victim, nb); | |
return victim; | |
} | |
else if (remainder_size >= 0) /* take */ | |
{ | |
set_inuse_bit_at_offset(victim, victim_size); | |
unlink(victim, bck, fwd); | |
check_malloced_chunk(ar_ptr, victim, nb); | |
return victim; | |
} | |
} | |
bin = next_bin(bin); | |
} while ((++idx & (BINBLOCKWIDTH - 1)) != 0); | |
/* Clear out the block bit. */ | |
do /* Possibly backtrack to try to clear a partial block */ | |
{ | |
if ((startidx & (BINBLOCKWIDTH - 1)) == 0) | |
{ | |
binblocks(ar_ptr) &= ~block; | |
break; | |
} | |
--startidx; | |
q = prev_bin(q); | |
} while (first(q) == q); | |
/* Get to the next possibly nonempty block */ | |
if ( (block <<= 1) <= binblocks(ar_ptr) && (block != 0) ) | |
{ | |
while ((block & binblocks(ar_ptr)) == 0) | |
{ | |
idx += BINBLOCKWIDTH; | |
block <<= 1; | |
} | |
} | |
else | |
break; | |
} | |
} | |
/* Try to use top chunk */ | |
/* Require that there be a remainder, ensuring top always exists */ | |
if ( (remainder_size = chunksize(top(ar_ptr)) - nb) < (long)MINSIZE) | |
{ | |
#if HAVE_MMAP | |
/* If the request is big and there are not yet too many regions, | |
and we would otherwise need to extend, try to use mmap instead. */ | |
if ((unsigned long)nb >= (unsigned long)mmap_threshold && | |
n_mmaps < n_mmaps_max && | |
(victim = mmap_chunk(nb)) != 0) | |
return victim; | |
#endif | |
/* Try to extend */ | |
malloc_extend_top(ar_ptr, nb); | |
if ((remainder_size = chunksize(top(ar_ptr)) - nb) < (long)MINSIZE) | |
{ | |
#if HAVE_MMAP | |
/* A last attempt: when we are out of address space in a | |
non-main arena, try mmap anyway, as long as it is allowed at | |
all. */ | |
if (ar_ptr != &main_arena && | |
n_mmaps_max > 0 && | |
(victim = mmap_chunk(nb)) != 0) | |
return victim; | |
#endif | |
return 0; /* propagate failure */ | |
} | |
} | |
victim = top(ar_ptr); | |
set_head(victim, nb | PREV_INUSE); | |
top(ar_ptr) = chunk_at_offset(victim, nb); | |
set_head(top(ar_ptr), remainder_size | PREV_INUSE); | |
check_malloced_chunk(ar_ptr, victim, nb); | |
return victim; | |
} | |
/* | |
free() algorithm : | |
cases: | |
1. free(0) has no effect. | |
2. If the chunk was allocated via mmap, it is released via munmap(). | |
3. If a returned chunk borders the current high end of memory, | |
it is consolidated into the top, and if the total unused | |
topmost memory exceeds the trim threshold, malloc_trim is | |
called. | |
4. Other chunks are consolidated as they arrive, and | |
placed in corresponding bins. (This includes the case of | |
consolidating with the current `last_remainder'). | |
*/ | |
#if __STD_C | |
void fREe(Void_t* mem) | |
#else | |
void fREe(mem) Void_t* mem; | |
#endif | |
{ | |
arena *ar_ptr; | |
mchunkptr p; /* chunk corresponding to mem */ | |
#if defined _LIBC || defined MALLOC_HOOKS | |
void (*hook) __MALLOC_PMT ((__malloc_ptr_t, __const __malloc_ptr_t)) = | |
__free_hook; | |
if (hook != NULL) { | |
#if defined __GNUC__ && __GNUC__ >= 2 | |
(*hook)(mem, RETURN_ADDRESS (0)); | |
#else | |
(*hook)(mem, NULL); | |
#endif | |
return; | |
} | |
#endif | |
if (mem == 0) /* free(0) has no effect */ | |
return; | |
p = mem2chunk(mem); | |
#if HAVE_MMAP | |
if (chunk_is_mmapped(p)) /* release mmapped memory. */ | |
{ | |
munmap_chunk(p); | |
return; | |
} | |
#endif | |
ar_ptr = arena_for_ptr(p); | |
#if THREAD_STATS | |
if(!mutex_trylock(&ar_ptr->mutex)) | |
++(ar_ptr->stat_lock_direct); | |
else { | |
(void)mutex_lock(&ar_ptr->mutex); | |
++(ar_ptr->stat_lock_wait); | |
} | |
#else | |
(void)mutex_lock(&ar_ptr->mutex); | |
#endif | |
chunk_free(ar_ptr, p); | |
(void)mutex_unlock(&ar_ptr->mutex); | |
} | |
static void | |
internal_function | |
#if __STD_C | |
chunk_free(arena *ar_ptr, mchunkptr p) | |
#else | |
chunk_free(ar_ptr, p) arena *ar_ptr; mchunkptr p; | |
#endif | |
{ | |
INTERNAL_SIZE_T hd = p->size; /* its head field */ | |
INTERNAL_SIZE_T sz; /* its size */ | |
int idx; /* its bin index */ | |
mchunkptr next; /* next contiguous chunk */ | |
INTERNAL_SIZE_T nextsz; /* its size */ | |
INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */ | |
mchunkptr bck; /* misc temp for linking */ | |
mchunkptr fwd; /* misc temp for linking */ | |
int islr; /* track whether merging with last_remainder */ | |
check_inuse_chunk(ar_ptr, p); | |
sz = hd & ~PREV_INUSE; | |
next = chunk_at_offset(p, sz); | |
nextsz = chunksize(next); | |
if (next == top(ar_ptr)) /* merge with top */ | |
{ | |
sz += nextsz; | |
if (!(hd & PREV_INUSE)) /* consolidate backward */ | |
{ | |
prevsz = p->prev_size; | |
p = chunk_at_offset(p, -(long)prevsz); | |
sz += prevsz; | |
unlink(p, bck, fwd); | |
} | |
set_head(p, sz | PREV_INUSE); | |
top(ar_ptr) = p; | |
#if USE_ARENAS | |
if(ar_ptr == &main_arena) { | |
#endif | |
if ((unsigned long)(sz) >= (unsigned long)trim_threshold) | |
main_trim(top_pad); | |
#if USE_ARENAS | |
} else { | |
heap_info *heap = heap_for_ptr(p); | |
assert(heap->ar_ptr == ar_ptr); | |
/* Try to get rid of completely empty heaps, if possible. */ | |
if((unsigned long)(sz) >= (unsigned long)trim_threshold || | |
p == chunk_at_offset(heap, sizeof(*heap))) | |
heap_trim(heap, top_pad); | |
} | |
#endif | |
return; | |
} | |
islr = 0; | |
if (!(hd & PREV_INUSE)) /* consolidate backward */ | |
{ | |
prevsz = p->prev_size; | |
p = chunk_at_offset(p, -(long)prevsz); | |
sz += prevsz; | |
if (p->fd == last_remainder(ar_ptr)) /* keep as last_remainder */ | |
islr = 1; | |
else | |
unlink(p, bck, fwd); | |
} | |
if (!(inuse_bit_at_offset(next, nextsz))) /* consolidate forward */ | |
{ | |
sz += nextsz; | |
if (!islr && next->fd == last_remainder(ar_ptr)) | |
/* re-insert last_remainder */ | |
{ | |
islr = 1; | |
link_last_remainder(ar_ptr, p); | |
} | |
else | |
unlink(next, bck, fwd); | |
next = chunk_at_offset(p, sz); | |
} | |
else | |
set_head(next, nextsz); /* clear inuse bit */ | |
set_head(p, sz | PREV_INUSE); | |
next->prev_size = sz; | |
if (!islr) | |
frontlink(ar_ptr, p, sz, idx, bck, fwd); | |