* [PATCH] dlmalloc: remove in favor of TLSF
@ 2025-06-16 13:04 Ahmad Fatoum
2025-06-17 6:54 ` Sascha Hauer
2025-06-17 6:56 ` Sascha Hauer
0 siblings, 2 replies; 3+ messages in thread
From: Ahmad Fatoum @ 2025-06-16 13:04 UTC (permalink / raw)
To: barebox; +Cc: Richard Weinberger, Ahmad Fatoum
We have had a TLSF implementation in barebox for >= 13 years now and it
has more features than the dlmalloc, which we inherited from U-Boot,
like multiple pools and KASAN integration.
We didn't have pressure to retire dlmalloc in that time, but bugs like
those fixed in commit 7cf25e0733f0 ("dlmalloc: Fix integer overflow in
request2size()") show that there's a security cost associated with
keeping bitrotted code, especially as we didn't document TLSF as being
the recommended allocator anywhere.
Since then, TLSF has been been made the default allocator in Kconfig[1]
and dlmalloc deprecation was announced[2]. Follow through now and drop
dlmalloc altogether.
[1]: Commit c1552409af30 ("common: make TLSF the default allocator")
[2]: https://lore.barebox.org/barebox/7a4edaef-a606-4b9d-bdf5-c7b5f896daae@pengutronix.de/
Cc: Antony Pavlov <antonynpavlov@gmail.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
.../migration-guides/migration-2025.07.0.rst | 5 +
common/Kconfig | 3 -
common/Makefile | 1 -
common/dlmalloc.c | 1976 -----------------
include/dlmalloc.h | 15 -
5 files changed, 5 insertions(+), 1995 deletions(-)
delete mode 100644 common/dlmalloc.c
delete mode 100644 include/dlmalloc.h
diff --git a/Documentation/migration-guides/migration-2025.07.0.rst b/Documentation/migration-guides/migration-2025.07.0.rst
index e8444544dfab..1d2d5b0f4267 100644
--- a/Documentation/migration-guides/migration-2025.07.0.rst
+++ b/Documentation/migration-guides/migration-2025.07.0.rst
@@ -8,6 +8,11 @@ Configuration options
It can be re-enabled using the newly added ``CONFIG_BOOT_ATAGS`` option.
Use of ATAGS is deprecated. Users should migrate to OpenFirmware device trees.
+* ``CONFIG_MALLOC_DLMALLOC`` has been removed in favor of ``CONFIG_MALLOC_TLSF``.
+ This should be a drop-in replacement, but it may unearth memory safety issues
+ that went unnoticed before. If this is suspected, ``CONFIG_KASAN`` should
+ help in debugging them on ARM.
+
Board support
-------------
diff --git a/common/Kconfig b/common/Kconfig
index a038e7200423..39a597bb704f 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -327,9 +327,6 @@ choice
prompt "malloc implementation"
default MALLOC_TLSF
-config MALLOC_DLMALLOC
- bool "dlmalloc"
-
config MALLOC_TLSF
bool "tlsf"
diff --git a/common/Makefile b/common/Makefile
index 9e258823d82d..0cead5e8b094 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -49,7 +49,6 @@ obj-$(CONFIG_FLEXIBLE_BOOTARGS) += bootargs.o
obj-$(CONFIG_GLOBALVAR) += globalvar.o
obj-$(CONFIG_GREGORIAN_CALENDER) += date.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
-obj-$(CONFIG_MALLOC_DLMALLOC) += dlmalloc.o
obj-$(CONFIG_MALLOC_TLSF) += tlsf_malloc.o tlsf.o calloc.o
KASAN_SANITIZE_tlsf.o := n
obj-$(CONFIG_MALLOC_DUMMY) += dummy_malloc.o calloc.o
diff --git a/common/dlmalloc.c b/common/dlmalloc.c
deleted file mode 100644
index c8e05ac68f2a..000000000000
--- a/common/dlmalloc.c
+++ /dev/null
@@ -1,1976 +0,0 @@
-
-#include <config.h>
-#include <errno.h>
-#include <malloc.h>
-#include <string.h>
-#include <memory.h>
-#include <dlmalloc.h>
-#include <linux/overflow.h>
-#include <linux/build_bug.h>
-#include <linux/compiler.h>
-
-#include <stdio.h>
-#include <module.h>
-
-/*
- A version of malloc/free/realloc written by Doug Lea and released to the
- public domain. Send questions/comments/complaints/performance data
- to dl@cs.oswego.edu
-
-* VERSION 2.6.6 Sun Mar 5 19:10:03 2000 Doug Lea (dl at gee)
-
- Note: There may be an updated version of this malloc obtainable at
- ftp://g.oswego.edu/pub/misc/malloc.c
- Check before installing!
-
-* 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
-
-* Synopsis of public routines
-
- (Much fuller descriptions are contained in the program documentation below.)
-
- dlmalloc(size_t n);
- Return a pointer to a newly allocated chunk of at least n bytes, or null
- if no space is available.
- dlfree(Void_t* p);
- Release the chunk of memory pointed to by p, or no effect if p is null.
- dlrealloc(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.
- dlmemalign(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.
- dlcalloc(size_t unit, size_t quantity);
- Returns a pointer to quantity * unit bytes, with all locations
- set to zero.
- 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.
- dlmalloc_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 when the request
- size is treaded as a long will return null.
-
- Maximum overhead wastage per allocated chunk: normally 15 bytes
-
- Alignnment 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 user-definable hooks for callbacks and the like.
- * 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. It is also reported to work on WIN32 platforms.
- 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.
- 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.
- REALLOC_ZERO_BYTES_FREES (default: NOT defined)
- Define this if you think that realloc(p, 0) should be equivalent
- to free(p). 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.
- 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.
- INTERNAL_LINUX_C_LIB (default: NOT defined)
- Defined only when compiled as part of Linux libc.
- 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.
- WIN32 (default: undefined)
- Define this on MS win (95, nt) platforms to compile in sbrk emulation.
- LACKS_UNISTD_H (default: undefined if not WIN32)
- Define this if your system does not have a <unistd.h>.
- LACKS_SYS_PARAM_H (default: undefined if not WIN32)
- Define this if your system does not have a <sys/param.h>.
- MORECORE (default: sbrk)
- The name of the routine to call to obtain more memory from the system.
- NULL (default: -1)
- The value returned upon failure of MORECORE.
- MORECORE_CLEARS (default 1)
- True (1) if the routine mapped to MORECORE zeroes out memory (which
- holds for sbrk).
- 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.
- USE_DL_PREFIX (default: undefined)
- Prefix all public routines with the string 'dl'. Useful to
- quickly avoid procedure declaration conflicts and linker symbol
- conflicts with existing memory allocation routines.
-
-
-*/
-
-#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 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 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
- means 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
-#define DEFAULT_MMAP_MAX (0)
-#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.
-*/
-
-/*
- 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.
- Some people think it should. Otherwise, since this malloc
- returns a unique pointer for malloc(0), so does realloc(p, 0).
-*/
-
-#define REALLOC_ZERO_BYTES_FREES
-
-/*
- 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().
-*/
-
-#define HAVE_MMAP 0 /* Not available for barebox */
-
-/*
- 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.
-*/
-
-#undef HAVE_MREMAP /* Not available for barebox */
-
-/*
-
- 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 */
-
-
-/* SVID2/XPG mallinfo structure */
-
-struct mallinfo
-{
- int arena; /* total space allocated from system */
- int ordblks; /* number of non-inuse chunks */
- int smblks; /* unused -- always zero */
- int hblks; /* number of mmapped regions */
- int hblkhd; /* total space in mmapped regions */
- int usmblks; /* unused -- always zero */
- int fsmblks; /* unused -- always zero */
- int uordblks; /* total allocated space */
- int fordblks; /* total non-inuse space */
- int keepcost; /* top-most, releasable (via malloc_trim) space */
-};
-
-/* SVID2/XPG mallopt options */
-
-#define M_MXFAST 1 /* UNUSED in this malloc */
-#define M_NLBLKS 2 /* UNUSED in this malloc */
-#define M_GRAIN 3 /* UNUSED in this malloc */
-#define M_KEEP 4 /* UNUSED in this malloc */
-
-/* mallopt options that actually do something */
-
-#define M_TRIM_THRESHOLD -1
-#define M_TOP_PAD -2
-#define M_MMAP_THRESHOLD -3
-#define M_MMAP_MAX -4
-
-/*
- 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
-*/
-
-#define malloc_getpagesize 4096
-
-/*
- 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.
-
-*/
-\f
-/* sizes, alignments */
-
-#define SIZE_SZ (sizeof(INTERNAL_SIZE_T))
-#define MALLOC_ALIGNMENT (SIZE_SZ + SIZE_SZ)
-#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*)((char*)(p) + 2*SIZE_SZ))
-
-static inline mchunkptr mem2chunk(void *mem)
-{
- OPTIMIZER_HIDE_VAR(mem);
-
- return mem - 2 * SIZE_SZ;
-}
-
-/* pad request bytes into a usable size */
-
-#define request2size(req) \
- ((((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
- (MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
- (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))
-
-/* 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 0x1
-
-/* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */
-
-#define IS_MMAPPED 0x2
-
-/* Bits to mask off when extracting size */
-
-#define SIZE_BITS (PREV_INUSE|IS_MMAPPED)
-
-/* 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)))
-
-/*
- Dealing with use bits
-*/
-
-/* extract p's inuse bit */
-
-#define inuse(p)\
-((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->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)\
-((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))
-
-/*
- 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) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))
-
-/*
- Bins
-
- The bins, `av_' 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.) The `av_' array is never mentioned
- directly in the code, but instead via bin access macros.
-
- 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;
-
-/* access macros */
-
-#define bin_at(i) ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ))
-#define next_bin(b) ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr)))
-#define prev_bin(b) ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr)))
-
-/*
- 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 top (bin_at(0)->fd) /* The topmost chunk */
-#define last_remainder (bin_at(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 ((mchunkptr)(bin_at(0)))
-
-/* Helper macro to initialize bins */
-
-#define IAV(i) bin_at(i), bin_at(i)
-
-static mbinptr av_[NAV * 2 + 2] = {
- NULL, NULL,
- 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)
-};
-
-/* 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 */
-
-#define binblocks (bin_at(0)->size) /* bitvector of nonempty blocks */
-
-/* bin<->block macros */
-
-#define idx2binblock(ix) ((unsigned)1 << (ix / BINBLOCKWIDTH))
-#define mark_binblock(ii) (binblocks |= idx2binblock(ii))
-#define clear_binblock(ii) (binblocks &= ~(idx2binblock(ii)))
-
-/* ----------------------------------------------------------------------- */
-
-/* Other static bookkeeping data */
-
-static_assert(MALLOC_ALIGNMENT >= CONFIG_MALLOC_ALIGNMENT);
-
-/* variables holding tunable values */
-#ifndef __BAREBOX__
-static unsigned long trim_threshold = DEFAULT_TRIM_THRESHOLD;
-static unsigned int n_mmaps_max = DEFAULT_MMAP_MAX;
-static unsigned long mmap_threshold = DEFAULT_MMAP_THRESHOLD;
-#endif
-static unsigned long top_pad = DEFAULT_TOP_PAD;
-
-/* 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 */
-static unsigned long max_total_mem;
-
-/* internal working copy of mallinfo */
-static struct mallinfo current_mallinfo;
-
-/* The total memory obtained from system via sbrk */
-#define sbrked_mem (current_mallinfo.arena)
-
-/* Tracking mmaps */
-
-static unsigned long mmapped_mem;
-
-/*
- 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(P, S, IDX, BK, FD) \
-{ \
- if (S < MAX_SMALLBIN_SIZE) \
- { \
- IDX = smallbin_index(S); \
- mark_binblock(IDX); \
- BK = bin_at(IDX); \
- FD = BK->fd; \
- P->bk = BK; \
- P->fd = FD; \
- FD->bk = BK->fd = P; \
- } \
- else \
- { \
- IDX = bin_index(S); \
- BK = bin_at(IDX); \
- FD = BK->fd; \
- if (FD == BK) mark_binblock(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(P) \
-{ \
- last_remainder->fd = last_remainder->bk = P; \
- P->fd = P->bk = last_remainder; \
-}
-
-/* Clear the last_remainder bin */
-
-#define clear_last_remainder \
- (last_remainder->fd = last_remainder->bk = last_remainder)
-
-/* Routines dealing with mmap(). */
-
-/*
- Extend the top-most chunk by obtaining memory from system.
- Main interface to sbrk (but see also malloc_trim).
-*/
-static void malloc_extend_top(INTERNAL_SIZE_T nb)
-{
- 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 */
- INTERNAL_SIZE_T top_size; /* new size of top chunk */
-
- mchunkptr old_top = top; /* Record state of old top */
- INTERNAL_SIZE_T old_top_size = chunksize(old_top);
- 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;
- unsigned long pagesz = malloc_getpagesize;
-
- /* 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*)(sbrk(sbrk_size));
-
- /* Fail if sbrk failed or if a foreign sbrk call killed our space */
- if (brk == (char*)(NULL) || (brk < old_end && old_top != initial_top))
- return;
-
- sbrked_mem += sbrk_size;
-
- if (brk == old_end) { /* can just add bytes to current top */
- top_size = sbrk_size + old_top_size;
- set_head (top, top_size | PREV_INUSE);
- } 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 += ((((unsigned long) (brk + sbrk_size)) +
- (pagesz - 1)) & ~(pagesz - 1)) -
- ((unsigned long) (brk + sbrk_size));
-
- /* Allocate correction */
- new_brk = (char*) (sbrk(correction));
- if (new_brk == (char*)(NULL))
- return;
-
- sbrked_mem += correction;
-
- top = (mchunkptr) brk;
- top_size = new_brk - brk + correction;
- set_head (top, top_size | PREV_INUSE);
-
- if (old_top != initial_top) {
-
- /* There must have been an intervening foreign sbrk call. */
- /* A double fencepost is necessary to prevent consolidation */
-
- /* If not enough space to do this, then user did something very wrong */
- if (old_top_size < MINSIZE) {
- set_head (top, PREV_INUSE); /* will force null return from malloc */
- return;
- }
-
- /* Also keep size a multiple of MALLOC_ALIGNMENT */
- old_top_size = (old_top_size -
- 3 * SIZE_SZ) & ~MALLOC_ALIGN_MASK;
- set_head_size (old_top, old_top_size);
- chunk_at_offset (old_top, old_top_size)->size =
- SIZE_SZ | PREV_INUSE;
- chunk_at_offset (old_top, old_top_size + SIZE_SZ)->size =
- SIZE_SZ | PREV_INUSE;
- /* If possible, release the rest. */
- if (old_top_size >= MINSIZE)
- dlfree(chunk2mem (old_top));
- }
- }
-
- if ((unsigned long) sbrked_mem > (unsigned long) max_sbrked_mem)
- max_sbrked_mem = sbrked_mem;
- if ((unsigned long) (mmapped_mem + sbrked_mem) > (unsigned long) max_total_mem)
- max_total_mem = mmapped_mem + sbrked_mem;
-}
-
-/* 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 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 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.)
-*/
-void *dlmalloc(size_t bytes)
-{
- 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 */
-
- INTERNAL_SIZE_T nb;
-
- if (bytes > MALLOC_MAX_SIZE) {
- errno = ENOMEM;
- return NULL;
- } else if (bytes == 0) {
- return ZERO_SIZE_PTR;
- }
-
- nb = request2size(bytes); /* padded request size; */
-
- /* 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(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);
- return chunk2mem(victim);
- }
- idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */
- } else {
- idx = bin_index(nb);
- bin = bin_at(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);
- return chunk2mem(victim);
- }
- }
- ++idx;
- }
-
- /* Try to use the last split-off remainder */
-
- if ((victim = last_remainder->fd) != last_remainder) {
- 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(remainder);
- set_head(remainder, remainder_size | PREV_INUSE);
- set_foot(remainder, remainder_size);
- return chunk2mem(victim);
- }
-
- clear_last_remainder;
-
- if (remainder_size >= 0) { /* exhaust */
- set_inuse_bit_at_offset(victim, victim_size);
- return chunk2mem(victim);
- }
- /* Else place in bin */
- frontlink(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) {
- /* Get to the first marked block */
- if ((block & binblocks) == 0) {
- /* force to an even block boundary */
- idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH;
- block <<= 1;
- while ((block & binblocks) == 0) {
- idx += BINBLOCKWIDTH;
- block <<= 1;
- }
- }
-
- /* For each possibly nonempty block ... */
- for (;;) {
- startidx = idx; /* (track incomplete blocks) */
- q = bin = bin_at(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(remainder);
- set_head(remainder,
- remainder_size |
- PREV_INUSE);
- set_foot(remainder,
- remainder_size);
- return chunk2mem(victim);
- } else if (remainder_size >= 0) { /* take */
- set_inuse_bit_at_offset(victim,
- victim_size);
- unlink(victim, bck, fwd);
- return chunk2mem(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 &= ~block;
- break;
- }
- --startidx;
- q = prev_bin(q);
- } while (first(q) == q);
-
- /* Get to the next possibly nonempty block */
-
- if ((block <<= 1) <= binblocks && (block != 0)) {
- while ((block & binblocks) == 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) - nb) < (long) MINSIZE) {
- /* Try to extend */
- malloc_extend_top(nb);
- if ((remainder_size = chunksize(top) - nb) < (long) MINSIZE) {
- errno = ENOMEM;
- return NULL; /* propagate failure */
- }
- }
-
- victim = top;
- set_head(victim, nb | PREV_INUSE);
- top = chunk_at_offset(victim, nb);
- set_head(top, remainder_size | PREV_INUSE);
- return chunk2mem(victim);
-}
-
-/*
- free() algorithm :
-
- cases:
-
- 1. free(0) has no effect.
-
- 2. If the chunk was allocated via mmap, it is release 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').
-*/
-void dlfree(void *mem)
-{
- mchunkptr p; /* chunk corresponding to mem */
- INTERNAL_SIZE_T hd; /* 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 */
-
- if (ZERO_OR_NULL_PTR(mem)) /* free(0) has no effect */
- return;
-
- p = mem2chunk(mem);
- hd = p->size;
-
- if (want_init_on_free())
- memzero_explicit(mem, chunksize(p));
-
- sz = hd & ~PREV_INUSE;
- next = chunk_at_offset(p, sz);
- nextsz = chunksize(next);
-
- if (next == top) { /* 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 = p;
-#ifdef USE_MALLOC_TRIM
- if ((unsigned long) (sz) >= (unsigned long)trim_threshold)
- malloc_trim(top_pad);
-#endif
- return;
- }
-
- set_head(next, nextsz); /* clear inuse bit */
-
- 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) /* 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) { /* re-insert last_remainder */
- islr = 1;
- link_last_remainder(p);
- } else
- unlink(next, bck, fwd);
- }
-
-
- set_head(p, sz | PREV_INUSE);
- set_foot(p, sz);
- if (!islr)
- frontlink(p, sz, idx, bck, fwd);
-}
-
-size_t dlmalloc_usable_size(void *mem)
-{
- mchunkptr p;
-
- if (ZERO_OR_NULL_PTR(mem))
- return 0;
-
- p = mem2chunk(mem);
- return chunksize(p);
-}
-
-/*
- Realloc algorithm:
-
- Chunks that were obtained via mmap cannot be extended or shrunk
- unless HAVE_MREMAP is defined, in which case mremap is used.
- Otherwise, if their reallocation is for additional space, they are
- copied. If for less, they are just left alone.
-
- Otherwise, if the reallocation is for additional space, and the
- chunk can be extended, it is, else a malloc-copy-free sequence is
- taken. There are several different ways that a chunk could be
- extended. All are tried:
-
- * Extending forward into following adjacent free chunk.
- * Shifting backwards, joining preceding adjacent space
- * Both shifting backwards and extending forward.
- * Extending into newly sbrked space
-
- Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a
- size argument of zero (re)allocates a minimum-sized chunk.
-
- If the reallocation is for less space, and the new request is for
- a `small' (<512 bytes) size, then the newly unused space is lopped
- off and freed.
-
- The old unix realloc convention of allowing the last-free'd chunk
- to be used as an argument to realloc is no longer supported.
- I don't know of any programs still relying on this feature,
- and allowing it would also allow too many other incorrect
- usages of realloc to be sensible.
-*/
-void *dlrealloc(void *oldmem, size_t bytes)
-{
- INTERNAL_SIZE_T nb; /* padded request size */
-
- mchunkptr oldp; /* chunk corresponding to oldmem */
- INTERNAL_SIZE_T oldsize; /* its size */
-
- mchunkptr newp; /* chunk to return */
- INTERNAL_SIZE_T newsize; /* its size */
- void *newmem; /* corresponding user mem */
-
- mchunkptr next; /* next contiguous chunk after oldp */
- INTERNAL_SIZE_T nextsize; /* its size */
-
- mchunkptr prev; /* previous contiguous chunk before oldp */
- INTERNAL_SIZE_T prevsize; /* its size */
-
- mchunkptr remainder; /* holds split off extra space from newp */
- INTERNAL_SIZE_T remainder_size; /* its size */
-
- mchunkptr bck; /* misc temp for linking */
- mchunkptr fwd; /* misc temp for linking */
-
-#ifdef REALLOC_ZERO_BYTES_FREES
- if (bytes == 0) {
- dlfree(oldmem);
- return ZERO_SIZE_PTR;
- }
-#endif
-
- if (bytes > MALLOC_MAX_SIZE) {
- errno = ENOMEM;
- return NULL;
- }
-
- /* realloc of null is supposed to be same as malloc */
- if (ZERO_OR_NULL_PTR(oldmem))
- return dlmalloc(bytes);
-
- newp = oldp = mem2chunk(oldmem);
- newsize = oldsize = chunksize(oldp);
-
-
- nb = request2size(bytes);
-
-
- if ((long)(oldsize) < (long)(nb)) {
-
- /* Try expanding forward */
-
- next = chunk_at_offset(oldp, oldsize);
- if (next == top || !inuse(next)) {
- nextsize = chunksize(next);
-
- /* Forward into top only if a remainder */
- if (next == top) {
- if ((long)(nextsize + newsize) >=
- (long)(nb + MINSIZE)) {
- newsize += nextsize;
- top = chunk_at_offset(oldp, nb);
- set_head (top,
- (newsize - nb) | PREV_INUSE);
- set_head_size(oldp, nb);
- return chunk2mem(oldp);
- }
- }
-
- /* Forward into next chunk */
- else if (((long) (nextsize + newsize) >= (long) (nb))) {
- unlink(next, bck, fwd);
- newsize += nextsize;
- goto split;
- }
- } else {
- next = NULL;
- nextsize = 0;
- }
-
- /* Try shifting backwards. */
-
- if (!prev_inuse(oldp)) {
- prev = prev_chunk(oldp);
- prevsize = chunksize(prev);
-
- /* try forward + backward first to save a later consolidation */
-
- if (next) {
- /* into top */
- if (next == top) {
- if ((long)
- (nextsize + prevsize + newsize) >=
- (long)(nb + MINSIZE)) {
- unlink (prev, bck, fwd);
- newp = prev;
- newsize += prevsize + nextsize;
- newmem = chunk2mem(newp);
- memcpy(newmem, oldmem,
- oldsize - SIZE_SZ);
- top = chunk_at_offset(newp, nb);
- set_head(top,
- (newsize -
- nb) | PREV_INUSE);
- set_head_size(newp, nb);
- return newmem;
- }
- }
-
- /* into next chunk */
- else if (((long)(nextsize + prevsize + newsize)
- >= (long)(nb))) {
- unlink(next, bck, fwd);
- unlink(prev, bck, fwd);
- newp = prev;
- newsize += nextsize + prevsize;
- newmem = chunk2mem(newp);
- memcpy(newmem, oldmem,
- oldsize - SIZE_SZ);
- goto split;
- }
- }
-
- /* backward only */
- if (prev && (long)(prevsize + newsize) >= (long)nb) {
- unlink(prev, bck, fwd);
- newp = prev;
- newsize += prevsize;
- newmem = chunk2mem(newp);
- memcpy(newmem, oldmem, oldsize - SIZE_SZ);
- goto split;
- }
- }
-
- /* Must allocate */
-
- newmem = dlmalloc(bytes);
-
- if (!newmem) /* propagate failure */
- return NULL;
-
- /* Avoid copy if newp is next chunk after oldp. */
- /* (This can only happen when new chunk is sbrk'ed.) */
-
- if ((newp = mem2chunk(newmem)) == next_chunk(oldp)) {
- newsize += chunksize(newp);
- newp = oldp;
- goto split;
- }
-
- /* Otherwise copy, free, and exit */
- memcpy(newmem, oldmem, oldsize - SIZE_SZ);
- dlfree(oldmem);
- return newmem;
- }
-
-
-split: /* split off extra room in old or expanded chunk */
-
- if (newsize - nb >= MINSIZE) { /* split off remainder */
- remainder = chunk_at_offset(newp, nb);
- remainder_size = newsize - nb;
- set_head_size(newp, nb);
- set_head(remainder, remainder_size | PREV_INUSE);
- set_inuse_bit_at_offset(remainder, remainder_size);
- dlfree(chunk2mem(remainder)); /* let free() deal with it */
- } else {
- set_head_size(newp, newsize);
- set_inuse_bit_at_offset(newp, newsize);
- }
-
- return chunk2mem(newp);
-}
-
-/*
- memalign algorithm:
-
- memalign requests more than enough space from malloc, finds a spot
- within that chunk that meets the alignment request, and then
- possibly frees the leading and trailing space.
-
- The alignment argument must be a power of two. This property is not
- checked by memalign, so misuse may result in random runtime errors.
-
- 8-byte alignment is guaranteed by normal malloc calls, so don't
- bother calling memalign with an argument of 8 or less.
-
- Overreliance on memalign is a sure way to fragment space.
-*/
-void *dlmemalign(size_t alignment, size_t bytes)
-{
- INTERNAL_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 */
- INTERNAL_SIZE_T newsize; /* its size */
- INTERNAL_SIZE_T leadsize; /* leading space before alignment point */
- mchunkptr remainder; /* spare room at end to split off */
- long remainder_size; /* its size */
-
- if (bytes > MALLOC_MAX_SIZE || alignment > MALLOC_MAX_SIZE) {
- errno = ENOMEM;
- return NULL;
- }
-
- /* If need less alignment than we give anyway, just relay to malloc */
-
- if (alignment <= MALLOC_ALIGNMENT)
- return dlmalloc(bytes);
-
- /* Otherwise, ensure that it is at least a minimum chunk size */
-
- if (alignment < MINSIZE)
- alignment = MINSIZE;
-
- /* Call malloc with worst case padding to hit alignment. */
-
- nb = request2size(bytes);
- m = (char*)(dlmalloc(nb + alignment + MINSIZE));
-
- if (!m)
- return NULL; /* propagate failure */
-
- p = mem2chunk(m);
-
- if ((((unsigned long)(m)) % alignment) == 0) { /* aligned */
- } else { /* 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((void *)(((unsigned long) (m + alignment - 1)) &
- -((signed) alignment)));
- if ((long)(brk - (char*)(p)) < MINSIZE)
- brk = brk + alignment;
-
- newp = (mchunkptr)brk;
- leadsize = brk - (char*)(p);
- newsize = chunksize(p) - leadsize;
-
- /* give back leader, use the rest */
-
- set_head(newp, newsize | PREV_INUSE);
- set_inuse_bit_at_offset(newp, newsize);
- set_head_size(p, leadsize);
- dlfree(chunk2mem(p));
- p = newp;
- }
-
- /* Also give back spare room at the end */
-
- remainder_size = chunksize(p) - nb;
-
- if (remainder_size >= (long)MINSIZE) {
- remainder = chunk_at_offset(p, nb);
- set_head(remainder, remainder_size | PREV_INUSE);
- set_head_size(p, nb);
- dlfree(chunk2mem(remainder));
- }
-
- return chunk2mem(p);
-}
-
-/*
- *
- * calloc calls malloc, then zeroes out the allocated chunk.
- *
- */
-void *dlcalloc(size_t n, size_t elem_size)
-{
- mchunkptr p;
- INTERNAL_SIZE_T csz;
- INTERNAL_SIZE_T sz = size_mul(n, elem_size);
- void *mem;
-
- /* check if expand_top called, in which case don't need to clear */
- mchunkptr oldtop = top;
- INTERNAL_SIZE_T oldtopsize = chunksize(top);
-
- if (sz > MALLOC_MAX_SIZE) {
- errno = ENOMEM;
- return NULL;
- }
-
- mem = dlmalloc(sz);
-
- if (ZERO_OR_NULL_PTR(mem))
- return mem;
- else {
- p = mem2chunk(mem);
-
- /* Two optional cases in which clearing not necessary */
- csz = chunksize(p);
-
- if (p == oldtop && csz > oldtopsize) {
- /* clear only the bytes from non-freshly-sbrked memory */
- csz = oldtopsize;
- }
-
- memset(mem, 0, csz - SIZE_SZ);
- return mem;
- }
-}
-
-/* Utility to update current_mallinfo for malloc_stats and mallinfo() */
-
-static void malloc_update_mallinfo(void)
-{
- int i;
- mbinptr b;
- mchunkptr p;
-
-#ifdef DEBUG
- mchunkptr q;
-#endif
-
- INTERNAL_SIZE_T avail = chunksize(top);
- int navail = ((long)(avail) >= (long)MINSIZE) ? 1 : 0;
-
- for (i = 1; i < NAV; ++i) {
- b = bin_at (i);
- for (p = last(b); p != b; p = p->bk) {
-#ifdef DEBUG
- for (q = next_chunk(p);
- q < top && inuse(q)
- && (long) (chunksize(q)) >= (long)MINSIZE;
- q = next_chunk(q))
-#endif
- avail += chunksize(p);
- navail++;
- }
- }
-
- current_mallinfo.ordblks = navail;
- current_mallinfo.uordblks = sbrked_mem - avail;
- current_mallinfo.fordblks = avail;
-#if HAVE_MMAP
- current_mallinfo.hblks = n_mmaps;
-#endif
- current_mallinfo.hblkhd = mmapped_mem;
- current_mallinfo.keepcost = chunksize(top);
-
-}
-
-/*
- malloc_stats:
-
- Prints on the amount of space obtain from the system (both
- via sbrk and mmap), the maximum amount (which may be more than
- current if malloc_trim and/or munmap got called), the maximum
- number of simultaneous mmap regions used, and the current number
- of bytes allocated via malloc (or realloc, etc) but not yet
- freed. (Note that this is the number of bytes allocated, not the
- number requested. It will be larger than the number requested
- because of alignment and bookkeeping overhead.)
- */
-/*
- * mallinfo returns a copy of updated current mallinfo.
- */
-void malloc_stats(void)
-{
- malloc_update_mallinfo();
- printf("Maximum system memory: %u\n", (unsigned int)(max_total_mem));
- printf("Current system memory: %u\n",
- (unsigned int)(sbrked_mem + mmapped_mem));
- printf("in use: %u\n",
- (unsigned int)(current_mallinfo.uordblks + mmapped_mem));
-#if HAVE_MMAP
- printf("Maximum mmap'ed mmap regions: %u\n",
- (unsigned int) max_n_mmaps);
-#endif
-}
-
-/*
-
-History:
-
- V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
- * return null for negative arguments
- * Added Several WIN32 cleanups from Martin C. Fong <mcfong@yahoo.com>
- * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
- (e.g. WIN32 platforms)
- * Cleanup up header file inclusion for WIN32 platforms
- * Cleanup code to avoid Microsoft Visual C++ compiler complaints
- * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
- memory allocation routines
- * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
- * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
- usage of 'assert' in non-WIN32 code
- * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
- avoid infinite loop
- * Always call 'fREe()' rather than 'free()'
-
- V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
- * Fixed ordering problem with boundary-stamping
-
- V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee)
- * Added pvalloc, as recommended by H.J. Liu
- * Added 64bit pointer support mainly from Wolfram Gloger
- * Added anonymously donated WIN32 sbrk emulation
- * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
- * malloc_extend_top: fix mask error that caused wastage after
- foreign sbrks
- * Add linux mremap support code from HJ Liu
-
- V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee)
- * Integrated most documentation with the code.
- * Add support for mmap, with help from
- Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
- * Use last_remainder in more cases.
- * Pack bins using idea from colin@nyx10.cs.du.edu
- * Use ordered bins instead of best-fit threshold
- * Eliminate block-local decls to simplify tracing and debugging.
- * Support another case of realloc via move into top
- * Fix error occurring when initial sbrk_base not word-aligned.
- * Rely on page size for units instead of SBRK_UNIT to
- avoid surprises about sbrk alignment conventions.
- * Add mallinfo, mallopt. Thanks to Raymond Nijssen
- (raymond@es.ele.tue.nl) for the suggestion.
- * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
- * More precautions for cases where other routines call sbrk,
- courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
- * Added macros etc., allowing use in linux libc from
- H.J. Lu (hjl@gnu.ai.mit.edu)
- * Inverted this history list
-
- V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee)
- * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
- * Removed all preallocation code since under current scheme
- the work required to undo bad preallocations exceeds
- the work saved in good cases for most test programs.
- * No longer use return list or unconsolidated bins since
- no scheme using them consistently outperforms those that don't
- given above changes.
- * Use best fit for very large chunks to prevent some worst-cases.
- * Added some support for debugging
-
- V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee)
- * Removed footers when chunks are in use. Thanks to
- Paul Wilson (wilson@cs.texas.edu) for the suggestion.
-
- V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee)
- * Added malloc_trim, with help from Wolfram Gloger
- (wmglo@Dent.MED.Uni-Muenchen.DE).
-
- V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g)
-
- V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g)
- * realloc: try to expand in both directions
- * malloc: swap order of clean-bin strategy;
- * realloc: only conditionally expand backwards
- * Try not to scavenge used bins
- * Use bin counts as a guide to preallocation
- * Occasionally bin return list chunks in first scan
- * Add a few optimizations from colin@nyx10.cs.du.edu
-
- V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g)
- * faster bin computation & slightly different binning
- * merged all consolidations to one part of malloc proper
- (eliminating old malloc_find_space & malloc_clean_bin)
- * Scan 2 returns chunks (not just 1)
- * Propagate failure in realloc if malloc returns 0
- * Add stuff to allow compilation on non-ANSI compilers
- from kpv@research.att.com
-
- V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu)
- * removed potential for odd address access in prev_chunk
- * removed dependency on getpagesize.h
- * misc cosmetics and a bit more internal documentation
- * anticosmetics: mangled names in macros to evade debugger strangeness
- * tested on sparc, hp-700, dec-mips, rs6000
- with gcc & native cc (hp, dec only) allowing
- Detlefs & Zorn comparison study (in SIGPLAN Notices.)
-
- Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu)
- * Based loosely on libg++-1.2X malloc. (It retains some of the overall
- structure of old version, but most details differ.)
-
-*/
-
-#ifdef CONFIG_MALLOC_DLMALLOC
-#ifdef CONFIG_INIT_ON_ALLOC_DEFAULT_ON
-void *malloc(size_t bytes) { return dlcalloc(1, bytes); }
-#else
-void *malloc(size_t) __alias(dlmalloc);
-#endif
-EXPORT_SYMBOL(malloc);
-void *calloc(size_t, size_t) __alias(dlcalloc);
-EXPORT_SYMBOL(calloc);
-void free(void *) __alias(dlfree);
-EXPORT_SYMBOL(free);
-void *realloc(void *, size_t) __alias(dlrealloc);
-EXPORT_SYMBOL(realloc);
-void *memalign(size_t, size_t) __alias(dlmemalign);
-EXPORT_SYMBOL(memalign);
-size_t malloc_usable_size(void *) __alias(dlmalloc_usable_size);
-EXPORT_SYMBOL(malloc_usable_size);
-#endif
diff --git a/include/dlmalloc.h b/include/dlmalloc.h
deleted file mode 100644
index 90b647314230..000000000000
--- a/include/dlmalloc.h
+++ /dev/null
@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-#ifndef __DLMALLOC_H
-#define __DLMALLOC_H
-
-#include <linux/compiler.h>
-#include <types.h>
-
-void *dlmalloc(size_t) __alloc_size(1);
-size_t dlmalloc_usable_size(void *);
-void dlfree(void *);
-void *dlrealloc(void *, size_t) __realloc_size(2);
-void *dlmemalign(size_t, size_t) __alloc_size(2);
-void *dlcalloc(size_t, size_t) __alloc_size(1, 2);
-
-#endif /* __DLMALLOC_H */
--
2.39.5
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] dlmalloc: remove in favor of TLSF
2025-06-16 13:04 [PATCH] dlmalloc: remove in favor of TLSF Ahmad Fatoum
@ 2025-06-17 6:54 ` Sascha Hauer
2025-06-17 6:56 ` Sascha Hauer
1 sibling, 0 replies; 3+ messages in thread
From: Sascha Hauer @ 2025-06-17 6:54 UTC (permalink / raw)
To: barebox, Ahmad Fatoum; +Cc: Richard Weinberger
On Mon, 16 Jun 2025 15:04:30 +0200, Ahmad Fatoum wrote:
> We have had a TLSF implementation in barebox for >= 13 years now and it
> has more features than the dlmalloc, which we inherited from U-Boot,
> like multiple pools and KASAN integration.
>
> We didn't have pressure to retire dlmalloc in that time, but bugs like
> those fixed in commit 7cf25e0733f0 ("dlmalloc: Fix integer overflow in
> request2size()") show that there's a security cost associated with
> keeping bitrotted code, especially as we didn't document TLSF as being
> the recommended allocator anywhere.
>
> [...]
Applied, thanks!
[1/1] dlmalloc: remove in favor of TLSF
https://git.pengutronix.de/cgit/barebox/commit/?id=6c094fca7ca2 (link may not be stable)
Best regards,
--
Sascha Hauer <s.hauer@pengutronix.de>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] dlmalloc: remove in favor of TLSF
2025-06-16 13:04 [PATCH] dlmalloc: remove in favor of TLSF Ahmad Fatoum
2025-06-17 6:54 ` Sascha Hauer
@ 2025-06-17 6:56 ` Sascha Hauer
1 sibling, 0 replies; 3+ messages in thread
From: Sascha Hauer @ 2025-06-17 6:56 UTC (permalink / raw)
To: Ahmad Fatoum; +Cc: barebox, Richard Weinberger
On Mon, Jun 16, 2025 at 03:04:30PM +0200, Ahmad Fatoum wrote:
> We have had a TLSF implementation in barebox for >= 13 years now and it
> has more features than the dlmalloc, which we inherited from U-Boot,
> like multiple pools and KASAN integration.
>
> We didn't have pressure to retire dlmalloc in that time, but bugs like
> those fixed in commit 7cf25e0733f0 ("dlmalloc: Fix integer overflow in
> request2size()") show that there's a security cost associated with
> keeping bitrotted code, especially as we didn't document TLSF as being
> the recommended allocator anywhere.
>
> Since then, TLSF has been been made the default allocator in Kconfig[1]
> and dlmalloc deprecation was announced[2]. Follow through now and drop
> dlmalloc altogether.
>
> [1]: Commit c1552409af30 ("common: make TLSF the default allocator")
> [2]: https://lore.barebox.org/barebox/7a4edaef-a606-4b9d-bdf5-c7b5f896daae@pengutronix.de/
>
> Cc: Antony Pavlov <antonynpavlov@gmail.com>
> Cc: Richard Weinberger <richard@nod.at>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> .../migration-guides/migration-2025.07.0.rst | 5 +
> common/Kconfig | 3 -
> common/Makefile | 1 -
> common/dlmalloc.c | 1976 -----------------
> include/dlmalloc.h | 15 -
> 5 files changed, 5 insertions(+), 1995 deletions(-)
> delete mode 100644 common/dlmalloc.c
> delete mode 100644 include/dlmalloc.h
With this INTERNAL_SIZE_T becomes unused. Merged the following into
this commit
-------------------------8<-----------------------------
>From 5e436f98aba7dd371856acb41e34a2d4507016fe Mon Sep 17 00:00:00 2001
From: Sascha Hauer <s.hauer@pengutronix.de>
Date: Tue, 17 Jun 2025 08:54:08 +0200
Subject: [PATCH] fixup! dlmalloc: remove in favor of TLSF
---
arch/riscv/include/asm/types.h | 8 --------
arch/x86/include/asm/types.h | 13 -------------
2 files changed, 21 deletions(-)
diff --git a/arch/riscv/include/asm/types.h b/arch/riscv/include/asm/types.h
index add1c94fc7..f89733dcc4 100644
--- a/arch/riscv/include/asm/types.h
+++ b/arch/riscv/include/asm/types.h
@@ -5,12 +5,4 @@
#include <asm-generic/int-ll64.h>
-#if __riscv_xlen == 64
-/*
- * This is used in dlmalloc. On RISCV64 we need it to be 64 bit
- */
-#define INTERNAL_SIZE_T unsigned long
-
-#endif
-
#endif /* __ASM_RISCV_TYPES_H */
diff --git a/arch/x86/include/asm/types.h b/arch/x86/include/asm/types.h
index feb5843b9c..87813325f1 100644
--- a/arch/x86/include/asm/types.h
+++ b/arch/x86/include/asm/types.h
@@ -5,17 +5,4 @@
#include <asm-generic/int-ll64.h>
-#ifndef __ASSEMBLY__
-
-#ifdef __x86_64__
-/*
- * This is used in dlmalloc. On X86_64 we need it to be
- * 64 bit
- */
-#define INTERNAL_SIZE_T unsigned long
-
-#endif
-
-#endif
-
#endif
--
2.39.5
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-06-17 6:57 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2025-06-16 13:04 [PATCH] dlmalloc: remove in favor of TLSF Ahmad Fatoum
2025-06-17 6:54 ` Sascha Hauer
2025-06-17 6:56 ` Sascha Hauer
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox