[uClibc-cvs] uClibc/libc/stdlib/malloc-standard Makefile, NONE, 1.1 calloc.c, NONE, 1.1 free.c, NONE, 1.1 mallinfo.c, NONE, 1.1 malloc.c, NONE, 1.1 malloc.h, NONE, 1.1 mallopt.c, NONE, 1.1 memalign.c, NONE, 1.1 realloc.c, NONE, 1.1
Erik Andersen
andersen at uclibc.org
Tue Dec 30 10:40:52 UTC 2003
Update of /var/cvs/uClibc/libc/stdlib/malloc-standard
In directory nail:/tmp/cvs-serv5823/libc/stdlib/malloc-standard
Added Files:
Makefile calloc.c free.c mallinfo.c malloc.c malloc.h
mallopt.c memalign.c realloc.c
Log Message:
Rework malloc. The new default implementation is based on dlmalloc from Doug
Lea. It is about 2x faster than the old malloc-930716, and behave itself much
better -- it will properly release memory back to the system, and it uses a
combination of brk() for small allocations and mmap() for larger allocations.
-Erik
--- NEW FILE: realloc.c ---
/*
This is a version (aka dlmalloc) of malloc/free/realloc written by
Doug Lea and released to the public domain. Use, modify, and
redistribute this code without permission or acknowledgement in any
way you wish. Send questions, comments, complaints, performance
data, etc to dl at cs.oswego.edu
VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
ftp://gee.cs.oswego.edu/pub/misc/malloc.c
Check before installing!
Hacked up for uClibc by Erik Andersen <andersen at codepoet.org>
*/
#include "malloc.h"
/* ------------------------------ realloc ------------------------------ */
void* realloc(void* oldmem, size_t bytes)
{
mstate av;
size_t nb; /* padded request size */
mchunkptr oldp; /* chunk corresponding to oldmem */
size_t oldsize; /* its size */
mchunkptr newp; /* chunk to return */
size_t newsize; /* its size */
void* newmem; /* corresponding user mem */
mchunkptr next; /* next contiguous chunk after oldp */
mchunkptr remainder; /* extra space at end of newp */
unsigned long remainder_size; /* its size */
mchunkptr bck; /* misc temp for linking */
mchunkptr fwd; /* misc temp for linking */
unsigned long copysize; /* bytes to copy */
unsigned int ncopies; /* size_t words to copy */
size_t* s; /* copy source */
size_t* d; /* copy destination */
/* Check for special cases. */
if (! oldmem)
return malloc(bytes);
if (! bytes) {
free (oldmem);
return malloc(bytes);
}
LOCK;
av = get_malloc_state();
checked_request2size(bytes, nb);
oldp = mem2chunk(oldmem);
oldsize = chunksize(oldp);
check_inuse_chunk(oldp);
if (!chunk_is_mmapped(oldp)) {
if ((unsigned long)(oldsize) >= (unsigned long)(nb)) {
/* already big enough; split below */
newp = oldp;
newsize = oldsize;
}
else {
next = chunk_at_offset(oldp, oldsize);
/* Try to expand forward into top */
if (next == av->top &&
(unsigned long)(newsize = oldsize + chunksize(next)) >=
(unsigned long)(nb + MINSIZE)) {
set_head_size(oldp, nb);
av->top = chunk_at_offset(oldp, nb);
set_head(av->top, (newsize - nb) | PREV_INUSE);
UNLOCK;
return chunk2mem(oldp);
}
/* Try to expand forward into next chunk; split off remainder below */
else if (next != av->top &&
!inuse(next) &&
(unsigned long)(newsize = oldsize + chunksize(next)) >=
(unsigned long)(nb)) {
newp = oldp;
unlink(next, bck, fwd);
}
/* allocate, copy, free */
else {
newmem = malloc(nb - MALLOC_ALIGN_MASK);
if (newmem == 0) {
UNLOCK;
return 0; /* propagate failure */
}
newp = mem2chunk(newmem);
newsize = chunksize(newp);
/*
Avoid copy if newp is next chunk after oldp.
*/
if (newp == next) {
newsize += oldsize;
newp = oldp;
}
else {
/*
Unroll copy of <= 36 bytes (72 if 8byte sizes)
We know that contents have an odd number of
size_t-sized words; minimally 3.
*/
copysize = oldsize - (sizeof(size_t));
s = (size_t*)(oldmem);
d = (size_t*)(newmem);
ncopies = copysize / sizeof(size_t);
assert(ncopies >= 3);
if (ncopies > 9)
memcpy(d, s, copysize);
else {
*(d+0) = *(s+0);
*(d+1) = *(s+1);
*(d+2) = *(s+2);
if (ncopies > 4) {
*(d+3) = *(s+3);
*(d+4) = *(s+4);
if (ncopies > 6) {
*(d+5) = *(s+5);
*(d+6) = *(s+6);
if (ncopies > 8) {
*(d+7) = *(s+7);
*(d+8) = *(s+8);
}
}
}
}
free(oldmem);
check_inuse_chunk(newp);
UNLOCK;
return chunk2mem(newp);
}
}
}
/* If possible, free extra space in old or extended chunk */
assert((unsigned long)(newsize) >= (unsigned long)(nb));
remainder_size = newsize - nb;
if (remainder_size < MINSIZE) { /* not enough extra to split off */
set_head_size(newp, newsize);
set_inuse_bit_at_offset(newp, newsize);
}
else { /* split remainder */
remainder = chunk_at_offset(newp, nb);
set_head_size(newp, nb);
set_head(remainder, remainder_size | PREV_INUSE);
/* Mark remainder as inuse so free() won't complain */
set_inuse_bit_at_offset(remainder, remainder_size);
free(chunk2mem(remainder));
}
check_inuse_chunk(newp);
UNLOCK;
return chunk2mem(newp);
}
/*
Handle mmap cases
*/
else {
size_t offset = oldp->prev_size;
size_t pagemask = av->pagesize - 1;
char *cp;
unsigned long sum;
/* Note the extra (sizeof(size_t)) overhead */
newsize = (nb + offset + (sizeof(size_t)) + pagemask) & ~pagemask;
/* don't need to remap if still within same page */
if (oldsize == newsize - offset) {
UNLOCK;
return oldmem;
}
cp = (char*)mremap((char*)oldp - offset, oldsize + offset, newsize, 1);
if (cp != (char*)MORECORE_FAILURE) {
newp = (mchunkptr)(cp + offset);
set_head(newp, (newsize - offset)|IS_MMAPPED);
assert(aligned_OK(chunk2mem(newp)));
assert((newp->prev_size == offset));
/* update statistics */
sum = av->mmapped_mem += newsize - oldsize;
if (sum > (unsigned long)(av->max_mmapped_mem))
av->max_mmapped_mem = sum;
sum += av->sbrked_mem;
if (sum > (unsigned long)(av->max_total_mem))
av->max_total_mem = sum;
UNLOCK;
return chunk2mem(newp);
}
/* Note the extra (sizeof(size_t)) overhead. */
if ((unsigned long)(oldsize) >= (unsigned long)(nb + (sizeof(size_t))))
newmem = oldmem; /* do nothing */
else {
/* Must alloc, copy, free. */
newmem = malloc(nb - MALLOC_ALIGN_MASK);
if (newmem != 0) {
memcpy(newmem, oldmem, oldsize - 2*(sizeof(size_t)));
free(oldmem);
}
}
UNLOCK;
return newmem;
}
}
--- NEW FILE: mallinfo.c ---
/*
This is a version (aka dlmalloc) of malloc/free/realloc written by
Doug Lea and released to the public domain. Use, modify, and
redistribute this code without permission or acknowledgement in any
way you wish. Send questions, comments, complaints, performance
data, etc to dl at cs.oswego.edu
VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
ftp://gee.cs.oswego.edu/pub/misc/malloc.c
Check before installing!
Hacked up for uClibc by Erik Andersen <andersen at codepoet.org>
*/
#include "malloc.h"
/* ------------------------------ mallinfo ------------------------------ */
struct mallinfo mallinfo(void)
{
mstate av;
struct mallinfo mi;
int i;
mbinptr b;
mchunkptr p;
size_t avail;
size_t fastavail;
int nblocks;
int nfastblocks;
LOCK;
av = get_malloc_state();
/* Ensure initialization */
if (av->top == 0) {
__malloc_consolidate(av);
}
check_malloc_state();
/* Account for top */
avail = chunksize(av->top);
nblocks = 1; /* top always exists */
/* traverse fastbins */
nfastblocks = 0;
fastavail = 0;
for (i = 0; i < NFASTBINS; ++i) {
for (p = av->fastbins[i]; p != 0; p = p->fd) {
++nfastblocks;
fastavail += chunksize(p);
}
}
avail += fastavail;
/* traverse regular bins */
for (i = 1; i < NBINS; ++i) {
b = bin_at(av, i);
for (p = last(b); p != b; p = p->bk) {
++nblocks;
avail += chunksize(p);
}
}
mi.smblks = nfastblocks;
mi.ordblks = nblocks;
mi.fordblks = avail;
mi.uordblks = av->sbrked_mem - avail;
mi.arena = av->sbrked_mem;
mi.hblks = av->n_mmaps;
mi.hblkhd = av->mmapped_mem;
mi.fsmblks = fastavail;
mi.keepcost = chunksize(av->top);
mi.usmblks = av->max_total_mem;
UNLOCK;
return mi;
}
--- NEW FILE: malloc.h ---
/*
This is a version (aka dlmalloc) of malloc/free/realloc written by
Doug Lea and released to the public domain. Use, modify, and
redistribute this code without permission or acknowledgement in any
way you wish. Send questions, comments, complaints, performance
data, etc to dl at cs.oswego.edu
VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
ftp://gee.cs.oswego.edu/pub/misc/malloc.c
Check before installing!
Hacked up for uClibc by Erik Andersen <andersen at codepoet.org>
*/
#include <features.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <malloc.h>
#ifdef __UCLIBC_HAS_THREADS__
#include <pthread.h>
extern pthread_mutex_t __malloc_lock;
# define LOCK __pthread_mutex_lock(&__malloc_lock)
# define UNLOCK __pthread_mutex_unlock(&__malloc_lock);
#else
# define LOCK
# define UNLOCK
#endif
/*
MALLOC_ALIGNMENT is the minimum alignment for malloc'ed chunks.
It must be a power of two at least 2 * (sizeof(size_t)), even on machines
for which smaller alignments would suffice. It may be defined as
larger than this though. Note however that code and data structures
are optimized for the case of 8-byte alignment.
*/
#ifndef MALLOC_ALIGNMENT
#define MALLOC_ALIGNMENT (2 * (sizeof(size_t)))
#endif
/* The corresponding bit mask value */
#define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)
/*
TRIM_FASTBINS controls whether free() of a very small chunk can
immediately lead to trimming. Setting to true (1) can reduce memory
footprint, but will almost always slow down programs that use a lot
of small chunks.
Define this only if you are willing to give up some speed to more
aggressively reduce system-level memory footprint when releasing
memory in programs that use many small chunks. You can get
essentially the same effect by setting MXFAST to 0, but this can
lead to even greater slowdowns in programs using many small chunks.
TRIM_FASTBINS is an in-between compile-time option, that disables
only those chunks bordering topmost memory from being placed in
fastbins.
*/
#ifndef TRIM_FASTBINS
#define TRIM_FASTBINS 0
#endif
/*
MORECORE-related declarations. By default, rely on sbrk
*/
/*
MORECORE is the name of the routine to call to obtain more memory
from the system. See below for general guidance on writing
alternative MORECORE functions, as well as a version for WIN32 and a
sample version for pre-OSX macos.
*/
#ifndef MORECORE
#define MORECORE sbrk
#endif
/*
MORECORE_FAILURE is the value returned upon failure of MORECORE
as well as mmap. Since it cannot be an otherwise valid memory address,
and must reflect values of standard sys calls, you probably ought not
try to redefine it.
*/
#ifndef MORECORE_FAILURE
#define MORECORE_FAILURE (-1)
#endif
/*
If MORECORE_CONTIGUOUS is true, take advantage of fact that
consecutive calls to MORECORE with positive arguments always return
contiguous increasing addresses. This is true of unix sbrk. Even
if not defined, when regions happen to be contiguous, malloc will
permit allocations spanning regions obtained from different
calls. But defining this when applicable enables some stronger
consistency checks and space efficiencies.
*/
#ifndef MORECORE_CONTIGUOUS
#define MORECORE_CONTIGUOUS 1
#endif
/*
MMAP_AS_MORECORE_SIZE is the minimum mmap size argument to use if
sbrk fails, and mmap is used as a backup (which is done only if
HAVE_MMAP). The value must be a multiple of page size. This
backup strategy generally applies only when systems have "holes" in
address space, so sbrk cannot perform contiguous expansion, but
there is still space available on system. On systems for which
this is known to be useful (i.e. most linux kernels), this occurs
only when programs allocate huge amounts of memory. Between this,
and the fact that mmap regions tend to be limited, the size should
be large, to avoid too many mmap calls and thus avoid running out
of kernel resources.
*/
#ifndef MMAP_AS_MORECORE_SIZE
#define MMAP_AS_MORECORE_SIZE (1024 * 1024)
#endif
/*
The system page size. To the extent possible, this malloc manages
memory from the system in page-size units. Note that this value is
cached during initialization into a field of malloc_state. So even
if malloc_getpagesize is a function, it is only called once.
The following mechanics for getpagesize were adapted from bsd/gnu
getpagesize.h. If none of the system-probes here apply, a value of
4096 is used, which should be OK: If they don't apply, then using
the actual value probably doesn't impact performance.
*/
#ifndef malloc_getpagesize
# include <unistd.h>
# define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
#else /* just guess */
# define malloc_getpagesize (4096)
#endif
/* mallopt tuning options */
/*
M_MXFAST is the maximum request size used for "fastbins", special bins
that hold returned chunks without consolidating their spaces. This
enables future requests for chunks of the same size to be handled
very quickly, but can increase fragmentation, and thus increase the
overall memory footprint of a program.
This malloc manages fastbins very conservatively yet still
efficiently, so fragmentation is rarely a problem for values less
than or equal to the default. The maximum supported value of MXFAST
is 80. You wouldn't want it any higher than this anyway. Fastbins
are designed especially for use with many small structs, objects or
strings -- the default handles structs/objects/arrays with sizes up
to 16 4byte fields, or small strings representing words, tokens,
etc. Using fastbins for larger objects normally worsens
fragmentation without improving speed.
M_MXFAST is set in REQUEST size units. It is internally used in
chunksize units, which adds padding and alignment. You can reduce
M_MXFAST to 0 to disable all use of fastbins. This causes the malloc
algorithm to be a closer approximation of fifo-best-fit in all cases,
not just for larger requests, but will generally cause it to be
slower.
*/
/* M_MXFAST is a standard SVID/XPG tuning option, usually listed in malloc.h */
#ifndef M_MXFAST
#define M_MXFAST 1
#endif
#ifndef DEFAULT_MXFAST
#define DEFAULT_MXFAST 64
#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 this much memory.
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 tham 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 trim value must be greater than page size to have any useful
effect. To disable trimming completely, you can set to
(unsigned long)(-1)
Trim settings interact with fastbin (MXFAST) settings: Unless
TRIM_FASTBINS is defined, automatic trimming never takes place upon
freeing a chunk with size less than or equal to MXFAST. Trimming is
instead delayed until subsequent freeing of larger chunks. However,
you can still force an attempted trim by calling malloc_trim.
Also, trimming is not generally possible in cases where
the main arena is obtained via mmap.
Note that the trick some people use of mallocing a huge space and
then freeing it at program startup, in an attempt to reserve system
memory, doesn't have the intended effect under automatic trimming,
since that memory will immediately be returned to the system.
*/
#define M_TRIM_THRESHOLD -1
#ifndef DEFAULT_TRIM_THRESHOLD
#define DEFAULT_TRIM_THRESHOLD (256 * 1024)
#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.
*/
#define M_TOP_PAD -2
#ifndef DEFAULT_TOP_PAD
#define DEFAULT_TOP_PAD (0)
#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 benefits that:
1. 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.
2. Mapped memory can never become `locked' between
other chunks, as can happen with normally allocated chunks, which
means that even trimming via malloc_trim would not release them.
3. On some systems with "holes" in address spaces, mmap can obtain
memory that sbrk cannot.
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.
The advantages of mmap nearly always outweigh disadvantages for
"large" chunks, but the value of "large" varies across systems. The
default is an empirically derived value that works well in most
systems.
*/
#define M_MMAP_THRESHOLD -3
#ifndef DEFAULT_MMAP_THRESHOLD
#define DEFAULT_MMAP_THRESHOLD (256 * 1024)
#endif
/*
M_MMAP_MAX is the maximum number of requests to simultaneously
service using mmap. This parameter exists because
. Some systems have a limited number of internal tables for
use by mmap, and using more than a few of them may degrade
performance.
The default is set to a value that serves only as a safeguard.
Setting to 0 disables use of mmap for servicing large requests. If
HAVE_MMAP is not set, the default value is 0, and attempts to set it
to non-zero values in mallopt will fail.
*/
#define M_MMAP_MAX -4
#ifndef DEFAULT_MMAP_MAX
#define DEFAULT_MMAP_MAX (65536)
#endif
/* ------------------ MMAP support ------------------ */
#include <fcntl.h>
#include <sys/mman.h>
#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
#define MAP_ANONYMOUS MAP_ANON
#endif
#define MMAP(addr, size, prot, flags) \
(mmap((addr), (size), (prot), (flags)|MAP_ANONYMOUS, -1, 0))
/* ----------------------- Chunk representations ----------------------- */
/*
This struct declaration is misleading (but accurate and necessary).
It declares a "view" into memory allowing access to necessary
fields at known offsets from a given base. See explanation below.
*/
struct malloc_chunk {
size_t prev_size; /* Size of previous chunk (if free). */
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 boundries, so the mem portion
(which is returned to the user) is also on an even word boundary, and
thus at least 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. If
prev_inuse is set for any given chunk, then you CANNOT determine
the size of the previous chunk, and might even get a memory
addressing fault when trying to do so.
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 but can be very confusing when trying
to extend or adapt this code.
The two exceptions to all this are
1. The special chunk `top' 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.
2. Chunks allocated via mmap, which have the second-lowest-order
bit (IS_MMAPPED) set in their size fields. Because they are
allocated one-by-one, each must contain its own trailing size field.
*/
/*
---------- Size and alignment checks and conversions ----------
*/
/* conversion from malloc headers to user pointers, and back */
#define chunk2mem(p) ((void*)((char*)(p) + 2*(sizeof(size_t))))
#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*(sizeof(size_t))))
/* The smallest possible chunk */
#define MIN_CHUNK_SIZE (sizeof(struct malloc_chunk))
/* The smallest size we can malloc is an aligned minimal chunk */
#define MINSIZE \
(unsigned long)(((MIN_CHUNK_SIZE+MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK))
/* Check if m has acceptable alignment */
#define aligned_OK(m) (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)
/* Check if a request is so large that it would wrap around zero when
padded and aligned. To simplify some other code, the bound is made
low enough so that adding MINSIZE will also not wrap around sero.
*/
#define REQUEST_OUT_OF_RANGE(req) \
((unsigned long)(req) >= \
(unsigned long)(size_t)(-2 * MINSIZE))
/* pad request bytes into a usable size -- internal version */
#define request2size(req) \
(((req) + (sizeof(size_t)) + MALLOC_ALIGN_MASK < MINSIZE) ? \
MINSIZE : \
((req) + (sizeof(size_t)) + MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK)
/* Same, except also perform argument check */
#define checked_request2size(req, sz) \
if (REQUEST_OUT_OF_RANGE(req)) { \
errno = ENOMEM; \
return 0; \
} \
(sz) = request2size(req);
/*
--------------- Physical chunk operations ---------------
*/
/* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */
#define PREV_INUSE 0x1
/* extract inuse bit of previous chunk */
#define prev_inuse(p) ((p)->size & PREV_INUSE)
/* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */
#define IS_MMAPPED 0x2
/* check for mmap()'ed chunk */
#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)
/* Bits to mask off when extracting size
Note: IS_MMAPPED is intentionally not masked off from size field in
macros for which mmapped chunks should never be seen. This should
cause helpful core dumps to occur if it is tried by accident by
people extending or adapting this malloc.
*/
#define SIZE_BITS (PREV_INUSE|IS_MMAPPED)
/* Get size, ignoring use bits */
#define chunksize(p) ((p)->size & ~(SIZE_BITS))
/* Ptr to next physical malloc_chunk. */
#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) ))
/* Ptr to previous physical malloc_chunk */
#define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))
/* Treat space at ptr + offset as a chunk */
#define chunk_at_offset(p, s) ((mchunkptr)(((char*)(p)) + (s)))
/* extract p's inuse bit */
#define inuse(p)\
((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)
/* set/clear chunk as being inuse without otherwise disturbing */
#define set_inuse(p)\
((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE
#define clear_inuse(p)\
((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)
/* check/set/clear inuse bits in known places */
#define inuse_bit_at_offset(p, s)\
(((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)
#define set_inuse_bit_at_offset(p, s)\
(((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)
#define clear_inuse_bit_at_offset(p, s)\
(((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))
/* 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 field */
#define set_head(p, s) ((p)->size = (s))
/* Set size at footer (only when chunk is not in use) */
#define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))
/* -------------------- Internal data structures -------------------- */
/*
Bins
An array of bin headers for free 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. Most bins hold sizes that are
unusual as malloc request sizes, but are more usual for fragments
and consolidated sets of chunks, which is what these bins hold, so
they can be found quickly. All procedures maintain the invariant
that no consolidated chunk physically borders another one, so each
chunk in a list is known to be preceeded and followed by either
inuse chunks or the ends of memory.
Chunks in bins are kept in size order, with ties going to the
approximately least recently used chunk. Ordering isn't needed
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 (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.
To simplify use in double-linked lists, each bin header acts
as a malloc_chunk. This avoids special-casing for headers.
But to conserve space and improve locality, we allocate
only the fd/bk pointers of bins, and then use repositioning tricks
to treat these as the fields of a malloc_chunk*.
*/
typedef struct malloc_chunk* mbinptr;
/* addressing -- note that bin_at(0) does not exist */
#define bin_at(m, i) ((mbinptr)((char*)&((m)->bins[(i)<<1]) - ((sizeof(size_t))<<1)))
/* analog of ++bin */
#define next_bin(b) ((mbinptr)((char*)(b) + (sizeof(mchunkptr)<<1)))
/* Reminders about list directionality within bins */
#define first(b) ((b)->fd)
#define last(b) ((b)->bk)
/* Take a chunk off a bin list */
#define unlink(P, BK, FD) { \
FD = P->fd; \
BK = P->bk; \
FD->bk = BK; \
BK->fd = FD; \
}
/*
Indexing
Bins for sizes < 512 bytes contain chunks of all the same size, spaced
8 bytes apart. Larger bins are approximately logarithmically spaced:
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
The bins top out around 1MB because we expect to service large
requests via mmap.
*/
#define NBINS 96
#define NSMALLBINS 32
#define SMALLBIN_WIDTH 8
#define MIN_LARGE_SIZE 256
#define in_smallbin_range(sz) \
((unsigned long)(sz) < (unsigned long)MIN_LARGE_SIZE)
#define smallbin_index(sz) (((unsigned)(sz)) >> 3)
#define bin_index(sz) \
((in_smallbin_range(sz)) ? smallbin_index(sz) : __malloc_largebin_index(sz))
/*
FIRST_SORTED_BIN_SIZE is the chunk size corresponding to the
first bin that is maintained in sorted order. This must
be the smallest size corresponding to a given bin.
Normally, this should be MIN_LARGE_SIZE. But you can weaken
best fit guarantees to sometimes speed up malloc by increasing value.
Doing this means that malloc may choose a chunk that is
non-best-fitting by up to the width of the bin.
Some useful cutoff values:
512 - all bins sorted
2560 - leaves bins <= 64 bytes wide unsorted
12288 - leaves bins <= 512 bytes wide unsorted
65536 - leaves bins <= 4096 bytes wide unsorted
262144 - leaves bins <= 32768 bytes wide unsorted
-1 - no bins sorted (not recommended!)
*/
#define FIRST_SORTED_BIN_SIZE MIN_LARGE_SIZE
/* #define FIRST_SORTED_BIN_SIZE 65536 */
/*
Unsorted chunks
All remainders from chunk splits, as well as all returned chunks,
are first placed in the "unsorted" bin. They are then placed
in regular bins after malloc gives them ONE chance to be used before
binning. So, basically, the unsorted_chunks list acts as a queue,
with chunks being placed on it in free (and __malloc_consolidate),
and taken off (to be either used or placed in bins) in malloc.
*/
/* The otherwise unindexable 1-bin is used to hold unsorted chunks. */
#define unsorted_chunks(M) (bin_at(M, 1))
/*
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). 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 do so when getting memory from system, so we make
initial_top treat the bin as a legal but unusable chunk during the
interval between initialization and the first call to
__malloc_alloc. (This is somewhat delicate, since it relies on
the 2 preceding words to be zero during this interval as well.)
*/
/* Conveniently, the unsorted bin can be used as dummy top on first call */
#define initial_top(M) (unsorted_chunks(M))
/*
Binmap
To help compensate for the large number of bins, a one-level index
structure is used for bin-by-bin searching. `binmap' is a
bitvector recording whether bins are definitely empty so they can
be skipped over during during traversals. The bits are NOT always
cleared as soon as bins are empty, but instead only
when they are noticed to be empty during traversal in malloc.
*/
/* Conservatively use 32 bits per map word, even if on 64bit system */
#define BINMAPSHIFT 5
#define BITSPERMAP (1U << BINMAPSHIFT)
#define BINMAPSIZE (NBINS / BITSPERMAP)
#define idx2block(i) ((i) >> BINMAPSHIFT)
#define idx2bit(i) ((1U << ((i) & ((1U << BINMAPSHIFT)-1))))
#define mark_bin(m,i) ((m)->binmap[idx2block(i)] |= idx2bit(i))
#define unmark_bin(m,i) ((m)->binmap[idx2block(i)] &= ~(idx2bit(i)))
#define get_binmap(m,i) ((m)->binmap[idx2block(i)] & idx2bit(i))
/*
Fastbins
An array of lists holding recently freed small chunks. Fastbins
are not doubly linked. It is faster to single-link them, and
since chunks are never removed from the middles of these lists,
double linking is not necessary. Also, unlike regular bins, they
are not even processed in FIFO order (they use faster LIFO) since
ordering doesn't much matter in the transient contexts in which
fastbins are normally used.
Chunks in fastbins keep their inuse bit set, so they cannot
be consolidated with other free chunks. __malloc_consolidate
releases all chunks in fastbins and consolidates them with
other free chunks.
*/
typedef struct malloc_chunk* mfastbinptr;
/* offset 2 to use otherwise unindexable first 2 bins */
#define fastbin_index(sz) ((((unsigned int)(sz)) >> 3) - 2)
/* The maximum fastbin request size we support */
#define MAX_FAST_SIZE 80
#define NFASTBINS (fastbin_index(request2size(MAX_FAST_SIZE))+1)
/*
FASTBIN_CONSOLIDATION_THRESHOLD is the size of a chunk in free()
that triggers automatic consolidation of possibly-surrounding
fastbin chunks. This is a heuristic, so the exact value should not
matter too much. It is defined at half the default trim threshold as a
compromise heuristic to only attempt consolidation if it is likely
to lead to trimming. However, it is not dynamically tunable, since
consolidation reduces fragmentation surrounding loarge chunks even
if trimming is not used.
*/
#define FASTBIN_CONSOLIDATION_THRESHOLD \
((unsigned long)(DEFAULT_TRIM_THRESHOLD) >> 1)
/*
Since the lowest 2 bits in max_fast don't matter in size comparisons,
they are used as flags.
*/
/*
ANYCHUNKS_BIT held in max_fast indicates that there may be any
freed chunks at all. It is set true when entering a chunk into any
bin.
*/
#define ANYCHUNKS_BIT (1U)
#define have_anychunks(M) (((M)->max_fast & ANYCHUNKS_BIT))
#define set_anychunks(M) ((M)->max_fast |= ANYCHUNKS_BIT)
#define clear_anychunks(M) ((M)->max_fast &= ~ANYCHUNKS_BIT)
/*
FASTCHUNKS_BIT held in max_fast indicates that there are probably
some fastbin chunks. It is set true on entering a chunk into any
fastbin, and cleared only in __malloc_consolidate.
*/
#define FASTCHUNKS_BIT (2U)
#define have_fastchunks(M) (((M)->max_fast & FASTCHUNKS_BIT))
#define set_fastchunks(M) ((M)->max_fast |= (FASTCHUNKS_BIT|ANYCHUNKS_BIT))
#define clear_fastchunks(M) ((M)->max_fast &= ~(FASTCHUNKS_BIT))
/* Set value of max_fast. Use impossibly small value if 0. */
#define set_max_fast(M, s) \
(M)->max_fast = (((s) == 0)? SMALLBIN_WIDTH: request2size(s)) | \
((M)->max_fast & (FASTCHUNKS_BIT|ANYCHUNKS_BIT))
#define get_max_fast(M) \
((M)->max_fast & ~(FASTCHUNKS_BIT | ANYCHUNKS_BIT))
/*
morecore_properties is a status word holding dynamically discovered
or controlled properties of the morecore function
*/
#define MORECORE_CONTIGUOUS_BIT (1U)
#define contiguous(M) \
(((M)->morecore_properties & MORECORE_CONTIGUOUS_BIT))
#define noncontiguous(M) \
(((M)->morecore_properties & MORECORE_CONTIGUOUS_BIT) == 0)
#define set_contiguous(M) \
((M)->morecore_properties |= MORECORE_CONTIGUOUS_BIT)
#define set_noncontiguous(M) \
((M)->morecore_properties &= ~MORECORE_CONTIGUOUS_BIT)
/*
----------- Internal state representation and initialization -----------
*/
struct malloc_state {
/* The maximum chunk size to be eligible for fastbin */
size_t max_fast; /* low 2 bits used as flags */
/* Fastbins */
mfastbinptr fastbins[NFASTBINS];
/* Base of the topmost chunk -- not otherwise kept in a bin */
mchunkptr top;
/* The remainder from the most recent split of a small request */
mchunkptr last_remainder;
/* Normal bins packed as described above */
mchunkptr bins[NBINS * 2];
/* Bitmap of bins. Trailing zero map handles cases of largest binned size */
unsigned int binmap[BINMAPSIZE+1];
/* Tunable parameters */
unsigned long trim_threshold;
size_t top_pad;
size_t mmap_threshold;
/* Memory map support */
int n_mmaps;
int n_mmaps_max;
int max_n_mmaps;
/* Cache malloc_getpagesize */
unsigned int pagesize;
/* Track properties of MORECORE */
unsigned int morecore_properties;
/* Statistics */
size_t mmapped_mem;
size_t sbrked_mem;
size_t max_sbrked_mem;
size_t max_mmapped_mem;
size_t max_total_mem;
};
typedef struct malloc_state *mstate;
/*
There is exactly one instance of this struct in this malloc.
If you are adapting this malloc in a way that does NOT use a static
malloc_state, you MUST explicitly zero-fill it before using. This
malloc relies on the property that malloc_state is initialized to
all zeroes (as is true of C statics).
*/
extern struct malloc_state __malloc_state; /* never directly referenced */
/*
All uses of av_ are via get_malloc_state().
At most one "call" to get_malloc_state is made per invocation of
the public versions of malloc and free, but other routines
that in turn invoke malloc and/or free may call more then once.
Also, it is called in check* routines if __MALLOC_DEBUGGING is set.
*/
#define get_malloc_state() (&(__malloc_state))
/* External internal utilities operating on mstates */
void __malloc_consolidate(mstate);
/* Debugging support */
#if ! __MALLOC_DEBUGGING
#define check_chunk(P)
#define check_free_chunk(P)
#define check_inuse_chunk(P)
#define check_remalloced_chunk(P,N)
#define check_malloced_chunk(P,N)
#define check_malloc_state()
#define assert(x) ((void)0)
#else
#define check_chunk(P) __do_check_chunk(P)
#define check_free_chunk(P) __do_check_free_chunk(P)
#define check_inuse_chunk(P) __do_check_inuse_chunk(P)
#define check_remalloced_chunk(P,N) __do_check_remalloced_chunk(P,N)
#define check_malloced_chunk(P,N) __do_check_malloced_chunk(P,N)
#define check_malloc_state() __do_check_malloc_state()
extern void __do_check_chunk(mchunkptr p);
extern void __do_check_free_chunk(mchunkptr p);
extern void __do_check_inuse_chunk(mchunkptr p);
extern void __do_check_remalloced_chunk(mchunkptr p, size_t s);
extern void __do_check_malloced_chunk(mchunkptr p, size_t s);
extern void __do_check_malloc_state(void);
#include <assert.h>
#endif
--- NEW FILE: Makefile ---
# Makefile for uClibc
#
# Copyright (C) 2000 by Lineo, inc.
# Copyright (C) 2000,2001 Erik Andersen <andersen at uclibc.org>
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU Library General Public License as published by the Free
# Software Foundation; either version 2 of the License, or (at your option) any
# later version.
#
# This program 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 Library General Public License for more
# details.
#
# You should have received a copy of the GNU Library General Public License
# along with this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# Derived in part from the Linux-8086 C library, the GNU C Library, and several
# other sundry sources. Files within this library are copyright by their
# respective copyright holders.
TOPDIR=../../../
include $(TOPDIR)Rules.mak
# Turn on malloc debugging if requested
ifeq ($(UCLIBC_MALLOC_DEBUGGING),y)
CFLAGS += -D__MALLOC_DEBUGGING
endif
# calloc.c can be found at uClibc/libc/stdlib/calloc.c
# valloc.c can be found at uClibc/libc/stdlib/valloc.c
CSRC=malloc.c calloc.c realloc.c free.c memalign.c mallopt.c mallinfo.c
COBJS=$(patsubst %.c,%.o, $(CSRC))
OBJS=$(COBJS)
all: $(OBJS) $(LIBC)
$(LIBC): ar-target
ar-target: $(OBJS)
$(AR) $(ARFLAGS) $(LIBC) $(OBJS)
$(COBJS): %.o : %.c
$(CC) $(CFLAGS) -c $< -o $@
$(STRIPTOOL) -x -R .note -R .comment $*.o
clean:
$(RM) *.[oa] *~ core
--- NEW FILE: malloc.c ---
/*
This is a version (aka dlmalloc) of malloc/free/realloc written by
Doug Lea and released to the public domain. Use, modify, and
redistribute this code without permission or acknowledgement in any
way you wish. Send questions, comments, complaints, performance
data, etc to dl at cs.oswego.edu
VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
ftp://gee.cs.oswego.edu/pub/misc/malloc.c
Check before installing!
Hacked up for uClibc by Erik Andersen <andersen at codepoet.org>
*/
#define _GNU_SOURCE
#include "malloc.h"
[...1121 lines suppressed...]
size = chunksize(victim);
if ((unsigned long)(size) >= (unsigned long)(nb + MINSIZE)) {
remainder_size = size - nb;
remainder = chunk_at_offset(victim, nb);
av->top = remainder;
set_head(victim, nb | PREV_INUSE);
set_head(remainder, remainder_size | PREV_INUSE);
check_malloced_chunk(victim, nb);
UNLOCK;
return chunk2mem(victim);
}
/* If no space in top, relay to handle system-dependent cases */
sysmem = __malloc_alloc(nb, av);
UNLOCK;
return sysmem;
}
--- NEW FILE: free.c ---
/*
This is a version (aka dlmalloc) of malloc/free/realloc written by
Doug Lea and released to the public domain. Use, modify, and
redistribute this code without permission or acknowledgement in any
way you wish. Send questions, comments, complaints, performance
data, etc to dl at cs.oswego.edu
VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
ftp://gee.cs.oswego.edu/pub/misc/malloc.c
Check before installing!
Hacked up for uClibc by Erik Andersen <andersen at codepoet.org>
*/
#include "malloc.h"
/* ------------------------- __malloc_trim -------------------------
__malloc_trim is an inverse of sorts to __malloc_alloc. It gives memory
back to the system (via negative arguments to sbrk) if there is unused
memory at the `high' end of the malloc pool. It is called automatically by
free() when top space exceeds the trim threshold. It is also called by the
public malloc_trim routine. It returns 1 if it actually released any
memory, else 0.
*/
static int __malloc_trim(size_t pad, mstate av)
{
long top_size; /* Amount of top-most memory */
long extra; /* Amount to release */
long released; /* Amount actually released */
char* current_brk; /* address returned by pre-check sbrk call */
char* new_brk; /* address returned by post-check sbrk call */
size_t pagesz;
pagesz = av->pagesize;
top_size = chunksize(av->top);
/* Release in pagesize units, keeping at least one page */
extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
if (extra > 0) {
/*
Only proceed if end of memory is where we last set it.
This avoids problems if there were foreign sbrk calls.
*/
current_brk = (char*)(MORECORE(0));
if (current_brk == (char*)(av->top) + top_size) {
/*
Attempt to release memory. We ignore MORECORE return value,
and instead call again to find out where new end of memory is.
This avoids problems if first call releases less than we asked,
of if failure somehow altered brk value. (We could still
encounter problems if it altered brk in some very bad way,
but the only thing we can do is adjust anyway, which will cause
some downstream failure.)
*/
MORECORE(-extra);
new_brk = (char*)(MORECORE(0));
if (new_brk != (char*)MORECORE_FAILURE) {
released = (long)(current_brk - new_brk);
if (released != 0) {
/* Success. Adjust top. */
av->sbrked_mem -= released;
set_head(av->top, (top_size - released) | PREV_INUSE);
check_malloc_state();
return 1;
}
}
}
}
return 0;
}
/*
Initialize a malloc_state struct.
This is called only from within __malloc_consolidate, which needs
be called in the same contexts anyway. It is never called directly
outside of __malloc_consolidate because some optimizing compilers try
to inline it at all call points, which turns out not to be an
optimization at all. (Inlining it in __malloc_consolidate is fine though.)
*/
static void malloc_init_state(mstate av)
{
int i;
mbinptr bin;
/* Establish circular links for normal bins */
for (i = 1; i < NBINS; ++i) {
bin = bin_at(av,i);
bin->fd = bin->bk = bin;
}
av->top_pad = DEFAULT_TOP_PAD;
av->n_mmaps_max = DEFAULT_MMAP_MAX;
av->mmap_threshold = DEFAULT_MMAP_THRESHOLD;
av->trim_threshold = DEFAULT_TRIM_THRESHOLD;
#if MORECORE_CONTIGUOUS
set_contiguous(av);
#else
set_noncontiguous(av);
#endif
set_max_fast(av, DEFAULT_MXFAST);
av->top = initial_top(av);
av->pagesize = malloc_getpagesize;
}
/* ----------------------------------------------------------------------
*
* PUBLIC STUFF
*
* ----------------------------------------------------------------------*/
/* ------------------------- __malloc_consolidate -------------------------
__malloc_consolidate is a specialized version of free() that tears
down chunks held in fastbins. Free itself cannot be used for this
purpose since, among other things, it might place chunks back onto
fastbins. So, instead, we need to use a minor variant of the same
code.
Also, because this routine needs to be called the first time through
malloc anyway, it turns out to be the perfect place to trigger
initialization code.
*/
void __malloc_consolidate(mstate av)
{
mfastbinptr* fb; /* current fastbin being consolidated */
mfastbinptr* maxfb; /* last fastbin (for loop control) */
mchunkptr p; /* current chunk being consolidated */
mchunkptr nextp; /* next chunk to consolidate */
mchunkptr unsorted_bin; /* bin header */
mchunkptr first_unsorted; /* chunk to link to */
/* These have same use as in free() */
mchunkptr nextchunk;
size_t size;
size_t nextsize;
size_t prevsize;
int nextinuse;
mchunkptr bck;
mchunkptr fwd;
/*
If max_fast is 0, we know that av hasn't
yet been initialized, in which case do so below
*/
if (av->max_fast != 0) {
clear_fastchunks(av);
unsorted_bin = unsorted_chunks(av);
/*
Remove each chunk from fast bin and consolidate it, placing it
then in unsorted bin. Among other reasons for doing this,
placing in unsorted bin avoids needing to calculate actual bins
until malloc is sure that chunks aren't immediately going to be
reused anyway.
*/
maxfb = &(av->fastbins[fastbin_index(av->max_fast)]);
fb = &(av->fastbins[0]);
do {
if ( (p = *fb) != 0) {
*fb = 0;
do {
check_inuse_chunk(p);
nextp = p->fd;
/* Slightly streamlined version of consolidation code in free() */
size = p->size & ~PREV_INUSE;
nextchunk = chunk_at_offset(p, size);
nextsize = chunksize(nextchunk);
if (!prev_inuse(p)) {
prevsize = p->prev_size;
size += prevsize;
p = chunk_at_offset(p, -((long) prevsize));
unlink(p, bck, fwd);
}
if (nextchunk != av->top) {
nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
set_head(nextchunk, nextsize);
if (!nextinuse) {
size += nextsize;
unlink(nextchunk, bck, fwd);
}
first_unsorted = unsorted_bin->fd;
unsorted_bin->fd = p;
first_unsorted->bk = p;
set_head(p, size | PREV_INUSE);
p->bk = unsorted_bin;
p->fd = first_unsorted;
set_foot(p, size);
}
else {
size += nextsize;
set_head(p, size | PREV_INUSE);
av->top = p;
}
} while ( (p = nextp) != 0);
}
} while (fb++ != maxfb);
}
else {
malloc_init_state(av);
check_malloc_state();
}
}
/* ------------------------------ free ------------------------------ */
void free(void* mem)
{
mstate av;
mchunkptr p; /* chunk corresponding to mem */
size_t size; /* its size */
mfastbinptr* fb; /* associated fastbin */
mchunkptr nextchunk; /* next contiguous chunk */
size_t nextsize; /* its size */
int nextinuse; /* true if nextchunk is used */
size_t prevsize; /* size of previous contiguous chunk */
mchunkptr bck; /* misc temp for linking */
mchunkptr fwd; /* misc temp for linking */
/* free(0) has no effect */
if (mem == NULL)
return;
LOCK;
av = get_malloc_state();
p = mem2chunk(mem);
size = chunksize(p);
check_inuse_chunk(p);
/*
If eligible, place chunk on a fastbin so it can be found
and used quickly in malloc.
*/
if ((unsigned long)(size) <= (unsigned long)(av->max_fast)
#if TRIM_FASTBINS
/* If TRIM_FASTBINS set, don't place chunks
bordering top into fastbins */
&& (chunk_at_offset(p, size) != av->top)
#endif
) {
set_fastchunks(av);
fb = &(av->fastbins[fastbin_index(size)]);
p->fd = *fb;
*fb = p;
}
/*
Consolidate other non-mmapped chunks as they arrive.
*/
else if (!chunk_is_mmapped(p)) {
set_anychunks(av);
nextchunk = chunk_at_offset(p, size);
nextsize = chunksize(nextchunk);
/* consolidate backward */
if (!prev_inuse(p)) {
prevsize = p->prev_size;
size += prevsize;
p = chunk_at_offset(p, -((long) prevsize));
unlink(p, bck, fwd);
}
if (nextchunk != av->top) {
/* get and clear inuse bit */
nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
set_head(nextchunk, nextsize);
/* consolidate forward */
if (!nextinuse) {
unlink(nextchunk, bck, fwd);
size += nextsize;
}
/*
Place the chunk in unsorted chunk list. Chunks are
not placed into regular bins until after they have
been given one chance to be used in malloc.
*/
bck = unsorted_chunks(av);
fwd = bck->fd;
p->bk = bck;
p->fd = fwd;
bck->fd = p;
fwd->bk = p;
set_head(p, size | PREV_INUSE);
set_foot(p, size);
check_free_chunk(p);
}
/*
If the chunk borders the current high end of memory,
consolidate into top
*/
else {
size += nextsize;
set_head(p, size | PREV_INUSE);
av->top = p;
check_chunk(p);
}
/*
If freeing a large space, consolidate possibly-surrounding
chunks. Then, if the total unused topmost memory exceeds trim
threshold, ask malloc_trim to reduce top.
Unless max_fast is 0, we don't know if there are fastbins
bordering top, so we cannot tell for sure whether threshold
has been reached unless fastbins are consolidated. But we
don't want to consolidate on each free. As a compromise,
consolidation is performed if FASTBIN_CONSOLIDATION_THRESHOLD
is reached.
*/
if ((unsigned long)(size) >= FASTBIN_CONSOLIDATION_THRESHOLD) {
if (have_fastchunks(av))
__malloc_consolidate(av);
if ((unsigned long)(chunksize(av->top)) >=
(unsigned long)(av->trim_threshold))
__malloc_trim(av->top_pad, av);
}
}
/*
If the chunk was allocated via mmap, release via munmap()
Note that if HAVE_MMAP is false but chunk_is_mmapped is
true, then user must have overwritten memory. There's nothing
we can do to catch this error unless DEBUG is set, in which case
check_inuse_chunk (above) will have triggered error.
*/
else {
int ret;
size_t offset = p->prev_size;
av->n_mmaps--;
av->mmapped_mem -= (size + offset);
ret = munmap((char*)p - offset, size + offset);
/* munmap returns non-zero on failure */
assert(ret == 0);
}
UNLOCK;
}
--- NEW FILE: calloc.c ---
/*
This is a version (aka dlmalloc) of malloc/free/realloc written by
Doug Lea and released to the public domain. Use, modify, and
redistribute this code without permission or acknowledgement in any
way you wish. Send questions, comments, complaints, performance
data, etc to dl at cs.oswego.edu
VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
ftp://gee.cs.oswego.edu/pub/misc/malloc.c
Check before installing!
Hacked up for uClibc by Erik Andersen <andersen at codepoet.org>
*/
#include "malloc.h"
/* ------------------------------ calloc ------------------------------ */
void* calloc(size_t n_elements, size_t elem_size)
{
mchunkptr p;
unsigned long clearsize;
unsigned long nclears;
size_t size, *d;
void* mem;
/* guard vs integer overflow, but allow nmemb
* to fall through and call malloc(0) */
size=lsize * nmemb;
if (n_elements && elem_size != (size / n_elements)) {
__set_errno(ENOMEM);
return NULL;
}
LOCK;
mem = malloc(size);
if (mem != 0) {
p = mem2chunk(mem);
if (!chunk_is_mmapped(p))
{
/*
Unroll clear of <= 36 bytes (72 if 8byte sizes)
We know that contents have an odd number of
size_t-sized words; minimally 3.
*/
d = (size_t*)mem;
clearsize = chunksize(p) - (sizeof(size_t));
nclears = clearsize / sizeof(size_t);
assert(nclears >= 3);
if (nclears > 9)
memset(d, 0, clearsize);
else {
*(d+0) = 0;
*(d+1) = 0;
*(d+2) = 0;
if (nclears > 4) {
*(d+3) = 0;
*(d+4) = 0;
if (nclears > 6) {
*(d+5) = 0;
*(d+6) = 0;
if (nclears > 8) {
*(d+7) = 0;
*(d+8) = 0;
}
}
}
}
}
#if 0
else
{
/* Standard unix mmap using /dev/zero clears memory so calloc
* doesn't need to actually zero anything....
*/
d = (size_t*)mem;
/* Note the additional (sizeof(size_t)) */
clearsize = chunksize(p) - 2*(sizeof(size_t));
memset(d, 0, clearsize);
}
#endif
}
UNLOCK;
return mem;
}
--- NEW FILE: mallopt.c ---
/*
This is a version (aka dlmalloc) of malloc/free/realloc written by
Doug Lea and released to the public domain. Use, modify, and
redistribute this code without permission or acknowledgement in any
way you wish. Send questions, comments, complaints, performance
data, etc to dl at cs.oswego.edu
VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
ftp://gee.cs.oswego.edu/pub/misc/malloc.c
Check before installing!
Hacked up for uClibc by Erik Andersen <andersen at codepoet.org>
*/
#include "malloc.h"
/* ------------------------------ mallopt ------------------------------ */
int mallopt(int param_number, int value)
{
int ret;
mstate av;
ret = 0;
LOCK;
av = get_malloc_state();
/* Ensure initialization/consolidation */
__malloc_consolidate(av);
switch(param_number) {
case M_MXFAST:
if (value >= 0 && value <= MAX_FAST_SIZE) {
set_max_fast(av, value);
ret = 1;
}
break;
case M_TRIM_THRESHOLD:
av->trim_threshold = value;
ret = 1;
break;
case M_TOP_PAD:
av->top_pad = value;
ret = 1;
break;
case M_MMAP_THRESHOLD:
av->mmap_threshold = value;
ret = 1;
break;
case M_MMAP_MAX:
av->n_mmaps_max = value;
ret = 1;
break;
}
UNLOCK;
return ret;
}
--- NEW FILE: memalign.c ---
/*
This is a version (aka dlmalloc) of malloc/free/realloc written by
Doug Lea and released to the public domain. Use, modify, and
redistribute this code without permission or acknowledgement in any
way you wish. Send questions, comments, complaints, performance
data, etc to dl at cs.oswego.edu
VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
ftp://gee.cs.oswego.edu/pub/misc/malloc.c
Check before installing!
Hacked up for uClibc by Erik Andersen <andersen at codepoet.org>
*/
#include <features.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include "malloc.h"
/* ------------------------------ memalign ------------------------------ */
void* memalign(size_t alignment, size_t bytes)
{
size_t nb; /* padded request size */
char* m; /* memory returned by malloc call */
mchunkptr p; /* corresponding chunk */
char* brk; /* alignment point within p */
mchunkptr newp; /* chunk to return */
size_t newsize; /* its size */
size_t leadsize; /* leading space before alignment point */
mchunkptr remainder; /* spare room at end to split off */
unsigned long remainder_size; /* its size */
size_t size;
/* If need less alignment than we give anyway, just relay to malloc */
if (alignment <= MALLOC_ALIGNMENT) return malloc(bytes);
/* Otherwise, ensure that it is at least a minimum chunk size */
if (alignment < MINSIZE) alignment = MINSIZE;
/* Make sure alignment is power of 2 (in case MINSIZE is not). */
if ((alignment & (alignment - 1)) != 0) {
size_t a = MALLOC_ALIGNMENT * 2;
while ((unsigned long)a < (unsigned long)alignment) a <<= 1;
alignment = a;
}
LOCK;
checked_request2size(bytes, nb);
/* Strategy: find a spot within that chunk that meets the alignment
* request, and then possibly free the leading and trailing space. */
/* Call malloc with worst case padding to hit alignment. */
m = (char*)(malloc(nb + alignment + MINSIZE));
if (m == 0) {
UNLOCK;
return 0; /* propagate failure */
}
p = mem2chunk(m);
if ((((unsigned long)(m)) % alignment) != 0) { /* misaligned */
/*
Find an aligned spot inside chunk. Since we need to give back
leading space in a chunk of at least MINSIZE, if the first
calculation places us at a spot with less than MINSIZE leader,
we can move to the next aligned spot -- we've allocated enough
total room so that this is always possible.
*/
brk = (char*)mem2chunk((unsigned long)(((unsigned long)(m + alignment - 1)) &
-((signed long) alignment)));
if ((unsigned long)(brk - (char*)(p)) < MINSIZE)
brk += alignment;
newp = (mchunkptr)brk;
leadsize = brk - (char*)(p);
newsize = chunksize(p) - leadsize;
/* For mmapped chunks, just adjust offset */
if (chunk_is_mmapped(p)) {
newp->prev_size = p->prev_size + leadsize;
set_head(newp, newsize|IS_MMAPPED);
UNLOCK;
return chunk2mem(newp);
}
/* Otherwise, give back leader, use the rest */
set_head(newp, newsize | PREV_INUSE);
set_inuse_bit_at_offset(newp, newsize);
set_head_size(p, leadsize);
free(chunk2mem(p));
p = newp;
assert (newsize >= nb &&
(((unsigned long)(chunk2mem(p))) % alignment) == 0);
}
/* Also give back spare room at the end */
if (!chunk_is_mmapped(p)) {
size = chunksize(p);
if ((unsigned long)(size) > (unsigned long)(nb + MINSIZE)) {
remainder_size = size - nb;
remainder = chunk_at_offset(p, nb);
set_head(remainder, remainder_size | PREV_INUSE);
set_head_size(p, nb);
free(chunk2mem(remainder));
}
}
check_inuse_chunk(p);
UNLOCK;
return chunk2mem(p);
}
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