| /* |
| This is a version (aka dlmalloc) of malloc/free/realloc written by |
| Doug Lea and released to the public domain, as explained at |
| http://creativecommons.org/publicdomain/zero/1.0/ Send questions, |
| comments, complaints, performance data, etc to dl@cs.oswego.edu |
| |
| * Version 2.8.6 Wed Aug 29 06:57:58 2012 Doug Lea |
| Note: There may be an updated version of this malloc obtainable at |
| ftp://gee.cs.oswego.edu/pub/misc/malloc.c |
| Check before installing! |
| |
| * Quickstart |
| |
| This library is all in one file to simplify the most common usage: |
| ftp it, compile it (-O3), and link it into another program. All of |
| the compile-time options default to reasonable values for use on |
| most platforms. You might later want to step through various |
| compile-time and dynamic tuning options. |
| |
| For convenience, an include file for code using this malloc is at: |
| ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.6.h |
| You don't really need this .h file unless you call functions not |
| defined in your system include files. The .h file contains only the |
| excerpts from this file needed for using this malloc on ANSI C/C++ |
| systems, so long as you haven't changed compile-time options about |
| naming and tuning parameters. If you do, then you can create your |
| own malloc.h that does include all settings by cutting at the point |
| indicated below. Note that you may already by default be using a C |
| library containing a malloc that is based on some version of this |
| malloc (for example in linux). You might still want to use the one |
| in this file to customize settings or to avoid overheads associated |
| with library versions. |
| |
| * Vital statistics: |
| |
| Supported pointer/size_t representation: 4 or 8 bytes |
| size_t MUST be an unsigned type of the same width as |
| pointers. (If you are using an ancient system that declares |
| size_t as a signed type, or need it to be a different width |
| than pointers, you can use a previous release of this malloc |
| (e.g. 2.7.2) supporting these.) |
| |
| Alignment: 8 bytes (minimum) |
| This suffices for nearly all current machines and C compilers. |
| However, you can define MALLOC_ALIGNMENT to be wider than this |
| if necessary (up to 128bytes), at the expense of using more space. |
| |
| Minimum overhead per allocated chunk: 4 or 8 bytes (if 4byte sizes) |
| 8 or 16 bytes (if 8byte sizes) |
| Each malloced chunk has a hidden word of overhead holding size |
| and status information, and additional cross-check word |
| if FOOTERS is defined. |
| |
| Minimum allocated size: 4-byte ptrs: 16 bytes (including overhead) |
| 8-byte ptrs: 32 bytes (including overhead) |
| |
| Even a request for zero bytes (i.e., malloc(0)) returns a |
| pointer to something of the minimum allocatable size. |
| The maximum overhead wastage (i.e., number of extra bytes |
| allocated than were requested in malloc) is less than or equal |
| to the minimum size, except for requests >= mmap_threshold that |
| are serviced via mmap(), where the worst case wastage is about |
| 32 bytes plus the remainder from a system page (the minimal |
| mmap unit); typically 4096 or 8192 bytes. |
| |
| Security: static-safe; optionally more or less |
| The "security" of malloc refers to the ability of malicious |
| code to accentuate the effects of errors (for example, freeing |
| space that is not currently malloc'ed or overwriting past the |
| ends of chunks) in code that calls malloc. This malloc |
| guarantees not to modify any memory locations below the base of |
| heap, i.e., static variables, even in the presence of usage |
| errors. The routines additionally detect most improper frees |
| and reallocs. All this holds as long as the static bookkeeping |
| for malloc itself is not corrupted by some other means. This |
| is only one aspect of security -- these checks do not, and |
| cannot, detect all possible programming errors. |
| |
| If FOOTERS is defined nonzero, then each allocated chunk |
| carries an additional check word to verify that it was malloced |
| from its space. These check words are the same within each |
| execution of a program using malloc, but differ across |
| executions, so externally crafted fake chunks cannot be |
| freed. This improves security by rejecting frees/reallocs that |
| could corrupt heap memory, in addition to the checks preventing |
| writes to statics that are always on. This may further improve |
| security at the expense of time and space overhead. (Note that |
| FOOTERS may also be worth using with MSPACES.) |
| |
| By default detected errors cause the program to abort (calling |
| "abort()"). You can override this to instead proceed past |
| errors by defining PROCEED_ON_ERROR. In this case, a bad free |
| has no effect, and a malloc that encounters a bad address |
| caused by user overwrites will ignore the bad address by |
| dropping pointers and indices to all known memory. This may |
| be appropriate for programs that should continue if at all |
| possible in the face of programming errors, although they may |
| run out of memory because dropped memory is never reclaimed. |
| |
| If you don't like either of these options, you can define |
| CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything |
| else. And if if you are sure that your program using malloc has |
| no errors or vulnerabilities, you can define INSECURE to 1, |
| which might (or might not) provide a small performance improvement. |
| |
| It is also possible to limit the maximum total allocatable |
| space, using malloc_set_footprint_limit. This is not |
| designed as a security feature in itself (calls to set limits |
| are not screened or privileged), but may be useful as one |
| aspect of a secure implementation. |
| |
| Thread-safety: NOT thread-safe unless USE_LOCKS defined non-zero |
| When USE_LOCKS is defined, each public call to malloc, free, |
| etc is surrounded with a lock. By default, this uses a plain |
| pthread mutex, win32 critical section, or a spin-lock if if |
| available for the platform and not disabled by setting |
| USE_SPIN_LOCKS=0. However, if USE_RECURSIVE_LOCKS is defined, |
| recursive versions are used instead (which are not required for |
| base functionality but may be needed in layered extensions). |
| Using a global lock is not especially fast, and can be a major |
| bottleneck. It is designed only to provide minimal protection |
| in concurrent environments, and to provide a basis for |
| extensions. If you are using malloc in a concurrent program, |
| consider instead using nedmalloc |
| (http://www.nedprod.com/programs/portable/nedmalloc/) or |
| ptmalloc (See http://www.malloc.de), which are derived from |
| versions of this malloc. |
| |
| System requirements: Any combination of MORECORE and/or MMAP/MUNMAP |
| This malloc can use unix sbrk or any emulation (invoked using |
| the CALL_MORECORE macro) and/or mmap/munmap or any emulation |
| (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system |
| memory. On most unix systems, it tends to work best if both |
| MORECORE and MMAP are enabled. On Win32, it uses emulations |
| based on VirtualAlloc. It also uses common C library functions |
| like memset. |
| |
| Compliance: I believe it is compliant with the Single Unix Specification |
| (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably |
| others as well. |
| |
| * Overview of algorithms |
| |
| 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 malloc-intensive programs. |
| |
| In most ways, this malloc is a best-fit allocator. Generally, it |
| chooses the best-fitting existing chunk for a request, with ties |
| broken in approximately least-recently-used order. (This strategy |
| normally maintains low fragmentation.) However, for requests less |
| than 256bytes, it deviates from best-fit when there is not an |
| exactly fitting available chunk by preferring to use space adjacent |
| to that used for the previous small request, as well as by breaking |
| ties in approximately most-recently-used order. (These enhance |
| locality of series of small allocations.) And for very large requests |
| (>= 256Kb by default), it relies on system memory mapping |
| facilities, if supported. (This helps avoid carrying around and |
| possibly fragmenting memory used only for large chunks.) |
| |
| All operations (except malloc_stats and mallinfo) have execution |
| times that are bounded by a constant factor of the number of bits in |
| a size_t, not counting any clearing in calloc or copying in realloc, |
| or actions surrounding MORECORE and MMAP that have times |
| proportional to the number of non-contiguous regions returned by |
| system allocation routines, which is often just 1. In real-time |
| applications, you can optionally suppress segment traversals using |
| NO_SEGMENT_TRAVERSAL, which assures bounded execution even when |
| system allocators return non-contiguous spaces, at the typical |
| expense of carrying around more memory and increased fragmentation. |
| |
| The implementation is not very modular and seriously overuses |
| macros. Perhaps someday all C compilers will do as good a job |
| inlining modular code as can now be done by brute-force expansion, |
| but now, enough of them seem not to. |
| |
| Some compilers issue a lot of warnings about code that is |
| dead/unreachable only on some platforms, and also about intentional |
| uses of negation on unsigned types. All known cases of each can be |
| ignored. |
| |
| For a longer but out of date high-level description, see |
| http://gee.cs.oswego.edu/dl/html/malloc.html |
| |
| * MSPACES |
| If MSPACES is defined, then in addition to malloc, free, etc., |
| this file also defines mspace_malloc, mspace_free, etc. These |
| are versions of malloc routines that take an "mspace" argument |
| obtained using create_mspace, to control all internal bookkeeping. |
| If ONLY_MSPACES is defined, only these versions are compiled. |
| So if you would like to use this allocator for only some allocations, |
| and your system malloc for others, you can compile with |
| ONLY_MSPACES and then do something like... |
| static mspace mymspace = create_mspace(0,0); // for example |
| #define mymalloc(bytes) mspace_malloc(mymspace, bytes) |
| |
| (Note: If you only need one instance of an mspace, you can instead |
| use "USE_DL_PREFIX" to relabel the global malloc.) |
| |
| You can similarly create thread-local allocators by storing |
| mspaces as thread-locals. For example: |
| static __thread mspace tlms = 0; |
| void* tlmalloc(size_t bytes) { |
| if (tlms == 0) tlms = create_mspace(0, 0); |
| return mspace_malloc(tlms, bytes); |
| } |
| void tlfree(void* mem) { mspace_free(tlms, mem); } |
| |
| Unless FOOTERS is defined, each mspace is completely independent. |
| You cannot allocate from one and free to another (although |
| conformance is only weakly checked, so usage errors are not always |
| caught). If FOOTERS is defined, then each chunk carries around a tag |
| indicating its originating mspace, and frees are directed to their |
| originating spaces. Normally, this requires use of locks. |
| |
| ------------------------- Compile-time options --------------------------- |
| |
| Be careful in setting #define values for numerical constants of type |
| size_t. On some systems, literal values are not automatically extended |
| to size_t precision unless they are explicitly casted. You can also |
| use the symbolic values MAX_SIZE_T, SIZE_T_ONE, etc below. |
| |
| WIN32 default: defined if _WIN32 defined |
| Defining WIN32 sets up defaults for MS environment and compilers. |
| Otherwise defaults are for unix. Beware that there seem to be some |
| cases where this malloc might not be a pure drop-in replacement for |
| Win32 malloc: Random-looking failures from Win32 GDI API's (eg; |
| SetDIBits()) may be due to bugs in some video driver implementations |
| when pixel buffers are malloc()ed, and the region spans more than |
| one VirtualAlloc()ed region. Because dlmalloc uses a small (64Kb) |
| default granularity, pixel buffers may straddle virtual allocation |
| regions more often than when using the Microsoft allocator. You can |
| avoid this by using VirtualAlloc() and VirtualFree() for all pixel |
| buffers rather than using malloc(). If this is not possible, |
| recompile this malloc with a larger DEFAULT_GRANULARITY. Note: |
| in cases where MSC and gcc (cygwin) are known to differ on WIN32, |
| conditions use _MSC_VER to distinguish them. |
| |
| DLMALLOC_EXPORT default: extern |
| Defines how public APIs are declared. If you want to export via a |
| Windows DLL, you might define this as |
| #define DLMALLOC_EXPORT extern __declspec(dllexport) |
| If you want a POSIX ELF shared object, you might use |
| #define DLMALLOC_EXPORT extern __attribute__((visibility("default"))) |
| |
| MALLOC_ALIGNMENT default: (size_t)(2 * sizeof(void *)) |
| Controls the minimum alignment for malloc'ed chunks. It must be a |
| power of two and at least 8, 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. |
| |
| MSPACES default: 0 (false) |
| If true, compile in support for independent allocation spaces. |
| This is only supported if HAVE_MMAP is true. |
| |
| ONLY_MSPACES default: 0 (false) |
| If true, only compile in mspace versions, not regular versions. |
| |
| USE_LOCKS default: 0 (false) |
| Causes each call to each public routine to be surrounded with |
| pthread or WIN32 mutex lock/unlock. (If set true, this can be |
| overridden on a per-mspace basis for mspace versions.) If set to a |
| non-zero value other than 1, locks are used, but their |
| implementation is left out, so lock functions must be supplied manually, |
| as described below. |
| |
| USE_SPIN_LOCKS default: 1 iff USE_LOCKS and spin locks available |
| If true, uses custom spin locks for locking. This is currently |
| supported only gcc >= 4.1, older gccs on x86 platforms, and recent |
| MS compilers. Otherwise, posix locks or win32 critical sections are |
| used. |
| |
| USE_RECURSIVE_LOCKS default: not defined |
| If defined nonzero, uses recursive (aka reentrant) locks, otherwise |
| uses plain mutexes. This is not required for malloc proper, but may |
| be needed for layered allocators such as nedmalloc. |
| |
| LOCK_AT_FORK default: not defined |
| If defined nonzero, performs pthread_atfork upon initialization |
| to initialize child lock while holding parent lock. The implementation |
| assumes that pthread locks (not custom locks) are being used. In other |
| cases, you may need to customize the implementation. |
| |
| FOOTERS default: 0 |
| If true, provide extra checking and dispatching by placing |
| information in the footers of allocated chunks. This adds |
| space and time overhead. |
| |
| INSECURE default: 0 |
| If true, omit checks for usage errors and heap space overwrites. |
| |
| USE_DL_PREFIX default: NOT defined |
| Causes compiler to prefix all public routines with the string 'dl'. |
| This can be useful when you only want to use this malloc in one part |
| of a program, using your regular system malloc elsewhere. |
| |
| MALLOC_INSPECT_ALL default: NOT defined |
| If defined, compiles malloc_inspect_all and mspace_inspect_all, that |
| perform traversal of all heap space. Unless access to these |
| functions is otherwise restricted, you probably do not want to |
| include them in secure implementations. |
| |
| DLM_ABORT default: defined as abort() |
| Defines how to abort on failed checks. On most systems, a failed |
| check cannot die with an "assert" or even print an informative |
| message, because the underlying print routines in turn call malloc, |
| which will fail again. Generally, the best policy is to simply call |
| abort(). It's not very useful to do more than this because many |
| errors due to overwriting will show up as address faults (null, odd |
| addresses etc) rather than malloc-triggered checks, so will also |
| abort. Also, most compilers know that abort() does not return, so |
| can better optimize code conditionally calling it. |
| |
| PROCEED_ON_ERROR default: defined as 0 (false) |
| Controls whether detected bad addresses cause them to bypassed |
| rather than aborting. If set, detected bad arguments to free and |
| realloc are ignored. And all bookkeeping information is zeroed out |
| upon a detected overwrite of freed heap space, thus losing the |
| ability to ever return it from malloc again, but enabling the |
| application to proceed. If PROCEED_ON_ERROR is defined, the |
| static variable malloc_corruption_error_count is compiled in |
| and can be examined to see if errors have occurred. This option |
| generates slower code than the default abort policy. |
| |
| DEBUG default: NOT defined |
| The DEBUG setting is mainly intended for people trying to modify |
| this code or diagnose problems when porting to new platforms. |
| However, it may also be able to better isolate user errors than just |
| using runtime checks. The assertions in the check routines spell |
| out in more detail the assumptions and invariants underlying the |
| algorithms. The checking is fairly extensive, and will slow down |
| execution noticeably. Calling malloc_stats or mallinfo with DEBUG |
| set will attempt to check every non-mmapped allocated and free chunk |
| in the course of computing the summaries. |
| |
| DLM_ABORT_ON_ASSERT_FAILURE default: defined as 1 (true) |
| Debugging assertion failures can be nearly impossible if your |
| version of the assert macro causes malloc to be called, which will |
| lead to a cascade of further failures, blowing the runtime stack. |
| DLM_ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(), |
| which will usually make debugging easier. |
| |
| MALLOC_FAILURE_ACTION default: sets errno to ENOMEM, or no-op on win32 |
| The action to take before "return 0" when malloc fails to be able to |
| return memory because there is none available. |
| |
| HAVE_MORECORE default: 1 (true) unless win32 or ONLY_MSPACES |
| True if this system supports sbrk or an emulation of it. |
| |
| MORECORE default: sbrk |
| The name of the sbrk-style system routine to call to obtain more |
| memory. See below for guidance on writing custom MORECORE |
| functions. The type of the argument to sbrk/MORECORE varies across |
| systems. It cannot be size_t, because it supports negative |
| arguments, so it is normally the signed type of the same width as |
| size_t (sometimes declared as "intptr_t"). It doesn't much matter |
| though. Internally, we only call it with arguments less than half |
| the max value of a size_t, which should work across all reasonable |
| possibilities, although sometimes generating compiler warnings. |
| |
| MORECORE_CONTIGUOUS default: 1 (true) if HAVE_MORECORE |
| If true, take advantage of fact that consecutive calls to MORECORE |
| with positive arguments always return contiguous increasing |
| addresses. This is true of unix sbrk. It does not hurt too much to |
| set it true anyway, since malloc copes with non-contiguities. |
| Setting it false when definitely non-contiguous saves time |
| and possibly wasted space it would take to discover this though. |
| |
| MORECORE_CANNOT_TRIM default: NOT defined |
| True if MORECORE cannot release space back to the system when given |
| negative arguments. This is generally necessary only if you are |
| using a hand-crafted MORECORE function that cannot handle negative |
| arguments. |
| |
| NO_SEGMENT_TRAVERSAL default: 0 |
| If non-zero, suppresses traversals of memory segments |
| returned by either MORECORE or CALL_MMAP. This disables |
| merging of segments that are contiguous, and selectively |
| releasing them to the OS if unused, but bounds execution times. |
| |
| HAVE_MMAP default: 1 (true) |
| True if this system supports mmap or an emulation of it. If so, and |
| HAVE_MORECORE is not true, MMAP is used for all system |
| allocation. If set and HAVE_MORECORE is true as well, MMAP is |
| primarily used to directly allocate very large blocks. It is also |
| used as a backup strategy in cases where MORECORE fails to provide |
| space from system. Note: A single call to MUNMAP is assumed to be |
| able to unmap memory that may have be allocated using multiple calls |
| to MMAP, so long as they are adjacent. |
| |
| HAVE_MREMAP default: 1 on linux, else 0 |
| If true realloc() uses mremap() to re-allocate large blocks and |
| extend or shrink allocation spaces. |
| |
| MMAP_CLEARS default: 1 except on WINCE. |
| True if mmap clears memory so calloc doesn't need to. This is true |
| for standard unix mmap using /dev/zero and on WIN32 except for WINCE. |
| |
| USE_BUILTIN_FFS default: 0 (i.e., not used) |
| Causes malloc to use the builtin ffs() function to compute indices. |
| Some compilers may recognize and intrinsify ffs to be faster than the |
| supplied C version. Also, the case of x86 using gcc is special-cased |
| to an asm instruction, so is already as fast as it can be, and so |
| this setting has no effect. Similarly for Win32 under recent MS compilers. |
| (On most x86s, the asm version is only slightly faster than the C version.) |
| |
| malloc_getpagesize default: derive from system includes, or 4096. |
| The system page size. To the extent possible, this malloc manages |
| memory from the system in page-size units. This may be (and |
| usually is) a function rather than a constant. This is ignored |
| if WIN32, where page size is determined using getSystemInfo during |
| initialization. |
| |
| USE_DEV_RANDOM default: 0 (i.e., not used) |
| Causes malloc to use /dev/random to initialize secure magic seed for |
| stamping footers. Otherwise, the current time is used. |
| |
| NO_MALLINFO default: 0 |
| If defined, don't compile "mallinfo". This can be a simple way |
| of dealing with mismatches between system declarations and |
| those in this file. |
| |
| MALLINFO_FIELD_TYPE default: size_t |
| The type of the fields in the mallinfo struct. This was originally |
| defined as "int" in SVID etc, but is more usefully defined as |
| size_t. The value is used only if HAVE_USR_INCLUDE_MALLOC_H is not set |
| |
| NO_MALLOC_STATS default: 0 |
| If defined, don't compile "malloc_stats". This avoids calls to |
| fprintf and bringing in stdio dependencies you might not want. |
| |
| REALLOC_ZERO_BYTES_FREES default: not defined |
| This 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). |
| |
| LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H |
| LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H, LACKS_ERRNO_H |
| LACKS_STDLIB_H LACKS_SCHED_H LACKS_TIME_H default: NOT defined unless on WIN32 |
| Define these if your system does not have these header files. |
| You might need to manually insert some of the declarations they provide. |
| |
| DEFAULT_GRANULARITY default: page size if MORECORE_CONTIGUOUS, |
| system_info.dwAllocationGranularity in WIN32, |
| otherwise 64K. |
| Also settable using mallopt(M_GRANULARITY, x) |
| The unit for allocating and deallocating memory from the system. On |
| most systems with contiguous MORECORE, there is no reason to |
| make this more than a page. However, systems with MMAP tend to |
| either require or encourage larger granularities. You can increase |
| this value to prevent system allocation functions to be called so |
| often, especially if they are slow. The value must be at least one |
| page and must be a power of two. Setting to 0 causes initialization |
| to either page size or win32 region size. (Note: In previous |
| versions of malloc, the equivalent of this option was called |
| "TOP_PAD") |
| |
| DEFAULT_TRIM_THRESHOLD default: 2MB |
| Also settable using mallopt(M_TRIM_THRESHOLD, x) |
| 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 using contiguous MORECORE. 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. 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 is worth tuning trim thresholds 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. The trim |
| value must be greater than page size to have any useful effect. To |
| disable trimming completely, you can set to MAX_SIZE_T. 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. |
| |
| DEFAULT_MMAP_THRESHOLD default: 256K |
| Also settable using mallopt(M_MMAP_THRESHOLD, x) |
| The request size threshold for using MMAP to directly 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: 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. Also, mapped memory doesn't 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 disadvantage that the space |
| cannot be reclaimed, consolidated, and then used to service later |
| requests, as happens with normal chunks. The advantages of mmap |
| nearly always outweigh disadvantages for "large" chunks, but the |
| value of "large" may vary across systems. The default is an |
| empirically derived value that works well in most systems. You can |
| disable mmap by setting to MAX_SIZE_T. |
| |
| MAX_RELEASE_CHECK_RATE default: 4095 unless not HAVE_MMAP |
| The number of consolidated frees between checks to release |
| unused segments when freeing. When using non-contiguous segments, |
| especially with multiple mspaces, checking only for topmost space |
| doesn't always suffice to trigger trimming. To compensate for this, |
| free() will, with a period of MAX_RELEASE_CHECK_RATE (or the |
| current number of segments, if greater) try to release unused |
| segments to the OS when freeing chunks that result in |
| consolidation. The best value for this parameter is a compromise |
| between slowing down frees with relatively costly checks that |
| rarely trigger versus holding on to unused memory. To effectively |
| disable, set to MAX_SIZE_T. This may lead to a very slight speed |
| improvement at the expense of carrying around more memory. |
| */ |
| |
| #include <vppinfra/clib.h> |
| #include <vppinfra/cache.h> |
| |
| /* --- begin vpp customizations --- */ |
| |
| #if CLIB_DEBUG > 0 |
| #define FOOTERS 1 /* extra debugging */ |
| #define DLM_MAGIC_CONSTANT 0xdeaddabe |
| #endif |
| #define USE_LOCKS 1 |
| #define DLM_ABORT {extern void os_panic(void); os_panic(); abort();} |
| #define ONLY_MSPACES 1 |
| |
| /* --- end vpp customizations --- */ |
| |
| /* Version identifier to allow people to support multiple versions */ |
| #ifndef DLMALLOC_VERSION |
| #define DLMALLOC_VERSION 20806 |
| #endif /* DLMALLOC_VERSION */ |
| |
| #ifndef DLMALLOC_EXPORT |
| #define DLMALLOC_EXPORT extern |
| #endif |
| |
| #ifndef WIN32 |
| #ifdef _WIN32 |
| #define WIN32 1 |
| #endif /* _WIN32 */ |
| #ifdef _WIN32_WCE |
| #define LACKS_FCNTL_H |
| #define WIN32 1 |
| #endif /* _WIN32_WCE */ |
| #endif /* WIN32 */ |
| #ifdef WIN32 |
| #define WIN32_LEAN_AND_MEAN |
| #include <windows.h> |
| #include <tchar.h> |
| #define HAVE_MMAP 1 |
| #define HAVE_MORECORE 0 |
| #define LACKS_UNISTD_H |
| #define LACKS_SYS_PARAM_H |
| #define LACKS_SYS_MMAN_H |
| #define LACKS_STRING_H |
| #define LACKS_STRINGS_H |
| #define LACKS_SYS_TYPES_H |
| #define LACKS_ERRNO_H |
| #define LACKS_SCHED_H |
| #ifndef MALLOC_FAILURE_ACTION |
| #define MALLOC_FAILURE_ACTION |
| #endif /* MALLOC_FAILURE_ACTION */ |
| #ifndef MMAP_CLEARS |
| #ifdef _WIN32_WCE /* WINCE reportedly does not clear */ |
| #define MMAP_CLEARS 0 |
| #else |
| #define MMAP_CLEARS 1 |
| #endif /* _WIN32_WCE */ |
| #endif /*MMAP_CLEARS */ |
| #endif /* WIN32 */ |
| |
| #if defined(DARWIN) || defined(_DARWIN) |
| /* Mac OSX docs advise not to use sbrk; it seems better to use mmap */ |
| #ifndef HAVE_MORECORE |
| #define HAVE_MORECORE 0 |
| #define HAVE_MMAP 1 |
| /* OSX allocators provide 16 byte alignment */ |
| #ifndef MALLOC_ALIGNMENT |
| #define MALLOC_ALIGNMENT ((size_t)16U) |
| #endif |
| #endif /* HAVE_MORECORE */ |
| #endif /* DARWIN */ |
| |
| #ifndef LACKS_SYS_TYPES_H |
| #include <sys/types.h> /* For size_t */ |
| #endif /* LACKS_SYS_TYPES_H */ |
| |
| /* The maximum possible size_t value has all bits set */ |
| #define MAX_SIZE_T (~(size_t)0) |
| |
| #ifndef USE_LOCKS /* ensure true if spin or recursive locks set */ |
| #define USE_LOCKS ((defined(USE_SPIN_LOCKS) && USE_SPIN_LOCKS != 0) || \ |
| (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0)) |
| #endif /* USE_LOCKS */ |
| |
| #if USE_LOCKS /* Spin locks for gcc >= 4.1, older gcc on x86, MSC >= 1310 */ |
| #if ((defined(__GNUC__) && \ |
| ((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) || \ |
| defined(__i386__) || defined(__x86_64__))) || \ |
| (defined(_MSC_VER) && _MSC_VER>=1310)) |
| #ifndef USE_SPIN_LOCKS |
| #define USE_SPIN_LOCKS 1 |
| #endif /* USE_SPIN_LOCKS */ |
| #elif USE_SPIN_LOCKS |
| #error "USE_SPIN_LOCKS defined without implementation" |
| #endif /* ... locks available... */ |
| #elif !defined(USE_SPIN_LOCKS) |
| #define USE_SPIN_LOCKS 0 |
| #endif /* USE_LOCKS */ |
| |
| #ifndef ONLY_MSPACES |
| #define ONLY_MSPACES 1 |
| #endif /* ONLY_MSPACES */ |
| #ifndef MSPACES |
| #if ONLY_MSPACES |
| #define MSPACES 1 |
| #else /* ONLY_MSPACES */ |
| #define MSPACES 0 |
| #endif /* ONLY_MSPACES */ |
| #endif /* MSPACES */ |
| #ifndef MALLOC_ALIGNMENT |
| #define MALLOC_ALIGNMENT ((size_t)(2 * sizeof(void *))) |
| #endif /* MALLOC_ALIGNMENT */ |
| #ifndef FOOTERS |
| #define FOOTERS 0 |
| #endif /* FOOTERS */ |
| #ifndef DLM_ABORT |
| #define DLM_ABORT abort() |
| #endif /* DLM_ABORT */ |
| #ifndef DLM_ABORT_ON_ASSERT_FAILURE |
| #define DLM_ABORT_ON_ASSERT_FAILURE 1 |
| #endif /* DLM_ABORT_ON_ASSERT_FAILURE */ |
| #ifndef PROCEED_ON_ERROR |
| #define PROCEED_ON_ERROR 0 |
| #endif /* PROCEED_ON_ERROR */ |
| |
| #ifndef INSECURE |
| #define INSECURE 0 |
| #endif /* INSECURE */ |
| #ifndef MALLOC_INSPECT_ALL |
| #define MALLOC_INSPECT_ALL 0 |
| #endif /* MALLOC_INSPECT_ALL */ |
| #ifndef HAVE_MMAP |
| #define HAVE_MMAP 1 |
| #endif /* HAVE_MMAP */ |
| #ifndef MMAP_CLEARS |
| #define MMAP_CLEARS 1 |
| #endif /* MMAP_CLEARS */ |
| #ifndef HAVE_MREMAP |
| #ifdef linux |
| #define HAVE_MREMAP 1 |
| #define _GNU_SOURCE /* Turns on mremap() definition */ |
| #else /* linux */ |
| #define HAVE_MREMAP 0 |
| #endif /* linux */ |
| #endif /* HAVE_MREMAP */ |
| #ifndef MALLOC_FAILURE_ACTION |
| #define MALLOC_FAILURE_ACTION errno = ENOMEM; |
| #endif /* MALLOC_FAILURE_ACTION */ |
| #ifndef HAVE_MORECORE |
| #if ONLY_MSPACES |
| #define HAVE_MORECORE 0 |
| #else /* ONLY_MSPACES */ |
| #define HAVE_MORECORE 1 |
| #endif /* ONLY_MSPACES */ |
| #endif /* HAVE_MORECORE */ |
| #if !HAVE_MORECORE |
| #define MORECORE_CONTIGUOUS 0 |
| #else /* !HAVE_MORECORE */ |
| #define MORECORE_DEFAULT sbrk |
| #ifndef MORECORE_CONTIGUOUS |
| #define MORECORE_CONTIGUOUS 1 |
| #endif /* MORECORE_CONTIGUOUS */ |
| #endif /* HAVE_MORECORE */ |
| #ifndef DEFAULT_GRANULARITY |
| #if (MORECORE_CONTIGUOUS || defined(WIN32)) |
| #define DEFAULT_GRANULARITY (0) /* 0 means to compute in init_mparams */ |
| #else /* MORECORE_CONTIGUOUS */ |
| #define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U) |
| #endif /* MORECORE_CONTIGUOUS */ |
| #endif /* DEFAULT_GRANULARITY */ |
| #ifndef DEFAULT_TRIM_THRESHOLD |
| #ifndef MORECORE_CANNOT_TRIM |
| #define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U) |
| #else /* MORECORE_CANNOT_TRIM */ |
| #define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T |
| #endif /* MORECORE_CANNOT_TRIM */ |
| #endif /* DEFAULT_TRIM_THRESHOLD */ |
| #ifndef DEFAULT_MMAP_THRESHOLD |
| #if HAVE_MMAP |
| /* |
| * The default value in the dlmalloc was set as follows: |
| * |
| * #define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U) |
| * |
| * Above this threshold the sys_alloc() calls mmap_alloc() to directly mmap the memory. |
| * However, the interaction of this path with the rest of the vpp infra results |
| * in vpp infra considering directly mmap-allocated pieces to not |
| * be part of the heap, with predictable consequence. |
| * |
| * A simple unit-test to show that behavior is to make a small private |
| * heap and repeatedly perform vec_add1() within that heap. |
| * |
| * The issue is because there is no tracking which mmap-allocated chunk |
| * belongs to which heap. |
| * |
| * The temporary approach is to dial up the threshold so that the problematic |
| * code path never gets called. The full fix needs to introduce |
| * introduce the vector of mmap-allocated chunks to mspace, and in general |
| * do some more thorough testing. |
| */ |
| #define DEFAULT_MMAP_THRESHOLD ((size_t)~0ULL) |
| #else /* HAVE_MMAP */ |
| #define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T |
| #endif /* HAVE_MMAP */ |
| #endif /* DEFAULT_MMAP_THRESHOLD */ |
| #ifndef MAX_RELEASE_CHECK_RATE |
| #if HAVE_MMAP |
| #define MAX_RELEASE_CHECK_RATE 4095 |
| #else |
| #define MAX_RELEASE_CHECK_RATE MAX_SIZE_T |
| #endif /* HAVE_MMAP */ |
| #endif /* MAX_RELEASE_CHECK_RATE */ |
| #ifndef USE_BUILTIN_FFS |
| #define USE_BUILTIN_FFS 0 |
| #endif /* USE_BUILTIN_FFS */ |
| #ifndef USE_DEV_RANDOM |
| #define USE_DEV_RANDOM 0 |
| #endif /* USE_DEV_RANDOM */ |
| #ifndef NO_MALLINFO |
| #define NO_MALLINFO 0 |
| #endif /* NO_MALLINFO */ |
| #ifndef MALLINFO_FIELD_TYPE |
| #define MALLINFO_FIELD_TYPE size_t |
| #endif /* MALLINFO_FIELD_TYPE */ |
| #ifndef NO_MALLOC_STATS |
| #define NO_MALLOC_STATS 0 |
| #endif /* NO_MALLOC_STATS */ |
| #ifndef NO_SEGMENT_TRAVERSAL |
| #define NO_SEGMENT_TRAVERSAL 0 |
| #endif /* NO_SEGMENT_TRAVERSAL */ |
| |
| /* |
| mallopt tuning options. SVID/XPG defines four standard parameter |
| numbers for mallopt, normally defined in malloc.h. None of these |
| are used in this malloc, so setting them has no effect. But this |
| malloc does support the following options. |
| */ |
| |
| #define M_TRIM_THRESHOLD (-1) |
| #define M_GRANULARITY (-2) |
| #define M_MMAP_THRESHOLD (-3) |
| |
| /* ------------------------ Mallinfo declarations ------------------------ */ |
| |
| #if !NO_MALLINFO |
| /* |
| This version of malloc supports the standard SVID/XPG mallinfo |
| routine that returns a struct containing usage properties and |
| statistics. It should work on any system that has a |
| /usr/include/malloc.h defining struct mallinfo. The main |
| declaration needed is the mallinfo struct that is returned (by-copy) |
| by mallinfo(). The malloinfo struct contains a bunch of fields that |
| are not even meaningful in this version of malloc. These fields are |
| are instead filled by mallinfo() with other numbers that might 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 a compliant version is |
| declared below. These must be precisely the same for mallinfo() to |
| work. The original SVID version of this struct, defined on most |
| systems with mallinfo, declares all fields as ints. But some others |
| define as unsigned long. If your system defines the fields using a |
| type of different width than listed here, you MUST #include your |
| system version and #define HAVE_USR_INCLUDE_MALLOC_H. |
| */ |
| |
| /* #define HAVE_USR_INCLUDE_MALLOC_H */ |
| |
| #if 0 // def HAVE_USR_INCLUDE_MALLOC_H |
| #include "/usr/include/malloc.h" |
| #else /* HAVE_USR_INCLUDE_MALLOC_H */ |
| #ifndef STRUCT_MALLINFO_DECLARED |
| /* HP-UX (and others?) redefines mallinfo unless _STRUCT_MALLINFO is defined */ |
| #define _STRUCT_MALLINFO |
| #define STRUCT_MALLINFO_DECLARED 1 |
| struct dlmallinfo { |
| MALLINFO_FIELD_TYPE arena; /* non-mmapped space allocated from system */ |
| MALLINFO_FIELD_TYPE ordblks; /* number of free chunks */ |
| MALLINFO_FIELD_TYPE smblks; /* always 0 */ |
| MALLINFO_FIELD_TYPE hblks; /* always 0 */ |
| MALLINFO_FIELD_TYPE hblkhd; /* space in mmapped regions */ |
| MALLINFO_FIELD_TYPE usmblks; /* maximum total allocated space */ |
| MALLINFO_FIELD_TYPE fsmblks; /* always 0 */ |
| MALLINFO_FIELD_TYPE uordblks; /* total allocated space */ |
| MALLINFO_FIELD_TYPE fordblks; /* total free space */ |
| MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */ |
| }; |
| #endif /* STRUCT_MALLINFO_DECLARED */ |
| #endif /* HAVE_USR_INCLUDE_MALLOC_H */ |
| #endif /* NO_MALLINFO */ |
| |
| /* |
| Try to persuade compilers to inline. The most critical functions for |
| inlining are defined as macros, so these aren't used for them. |
| */ |
| |
| #ifndef FORCEINLINE |
| #if defined(__GNUC__) |
| #define FORCEINLINE __inline __attribute__ ((always_inline)) |
| #elif defined(_MSC_VER) |
| #define FORCEINLINE __forceinline |
| #endif |
| #endif |
| #ifndef NOINLINE |
| #if defined(__GNUC__) |
| #define NOINLINE __attribute__ ((noinline)) |
| #elif defined(_MSC_VER) |
| #define NOINLINE __declspec(noinline) |
| #else |
| #define NOINLINE |
| #endif |
| #endif |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #ifndef FORCEINLINE |
| #define FORCEINLINE inline |
| #endif |
| #endif /* __cplusplus */ |
| #ifndef FORCEINLINE |
| #define FORCEINLINE |
| #endif |
| |
| #if !ONLY_MSPACES |
| |
| /* ------------------- Declarations of public routines ------------------- */ |
| |
| #ifndef USE_DL_PREFIX |
| #define dlcalloc calloc |
| #define dlfree free |
| #define dlmalloc malloc |
| #define dlmemalign memalign |
| #define dlposix_memalign posix_memalign |
| #define dlrealloc realloc |
| #define dlrealloc_in_place realloc_in_place |
| #define dlvalloc valloc |
| #define dlpvalloc pvalloc |
| // #define dlmallinfo mallinfo |
| #define dlmallopt mallopt |
| #define dlmalloc_trim malloc_trim |
| #define dlmalloc_stats malloc_stats |
| #define dlmalloc_usable_size malloc_usable_size |
| #define dlmalloc_footprint malloc_footprint |
| #define dlmalloc_max_footprint malloc_max_footprint |
| #define dlmalloc_footprint_limit malloc_footprint_limit |
| #define dlmalloc_set_footprint_limit malloc_set_footprint_limit |
| #define dlmalloc_inspect_all malloc_inspect_all |
| #define dlindependent_calloc independent_calloc |
| #define dlindependent_comalloc independent_comalloc |
| #define dlbulk_free bulk_free |
| #endif /* USE_DL_PREFIX */ |
| |
| /* |
| malloc(size_t n) |
| Returns a pointer to a newly allocated chunk of at least n bytes, or |
| null if no space is available, in which case errno is set to ENOMEM |
| on ANSI C systems. |
| |
| If n is zero, malloc returns a minimum-sized chunk. (The minimum |
| size is 16 bytes on most 32bit systems, and 32 bytes on 64bit |
| systems.) Note that size_t is an unsigned type, so calls with |
| arguments that would be negative if signed are interpreted as |
| requests for huge amounts of space, which will often fail. The |
| maximum supported value of n differs across systems, but is in all |
| cases less than the maximum representable value of a size_t. |
| */ |
| DLMALLOC_EXPORT void* dlmalloc(size_t); |
| |
| /* |
| free(void* p) |
| Releases the chunk of memory pointed to by p, that had been previously |
| allocated using malloc or a related routine such as realloc. |
| It has no effect if p is null. If p was not malloced or already |
| freed, free(p) will by default cause the current program to abort. |
| */ |
| DLMALLOC_EXPORT void dlfree(void*); |
| |
| /* |
| calloc(size_t n_elements, size_t element_size); |
| Returns a pointer to n_elements * element_size bytes, with all locations |
| set to zero. |
| */ |
| DLMALLOC_EXPORT void* dlcalloc(size_t, size_t); |
| |
| /* |
| realloc(void* p, size_t n) |
| Returns 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. The algorithm |
| prefers extending p in most cases when possible, otherwise it |
| employs the equivalent of a malloc-copy-free sequence. |
| |
| If p is null, realloc is equivalent to malloc. |
| |
| If space is not available, realloc returns null, errno is set (if on |
| ANSI) and p is NOT freed. |
| |
| if n is for fewer bytes than already held by p, the newly unused |
| space is lopped off and freed if possible. realloc with a size |
| argument of zero (re)allocates a minimum-sized chunk. |
| |
| The old unix realloc convention of allowing the last-free'd chunk |
| to be used as an argument to realloc is not supported. |
| */ |
| DLMALLOC_EXPORT void* dlrealloc(void*, size_t); |
| |
| /* |
| realloc_in_place(void* p, size_t n) |
| Resizes the space allocated for p to size n, only if this can be |
| done without moving p (i.e., only if there is adjacent space |
| available if n is greater than p's current allocated size, or n is |
| less than or equal to p's size). This may be used instead of plain |
| realloc if an alternative allocation strategy is needed upon failure |
| to expand space; for example, reallocation of a buffer that must be |
| memory-aligned or cleared. You can use realloc_in_place to trigger |
| these alternatives only when needed. |
| |
| Returns p if successful; otherwise null. |
| */ |
| DLMALLOC_EXPORT void* dlrealloc_in_place(void*, size_t); |
| |
| /* |
| memalign(size_t alignment, size_t n); |
| Returns a pointer to a newly allocated chunk of n bytes, aligned |
| in accord with the alignment argument. |
| |
| The alignment argument should be a power of two. If the argument is |
| not a power of two, the nearest greater power is used. |
| 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. |
| */ |
| DLMALLOC_EXPORT void* dlmemalign(size_t, size_t); |
| |
| /* |
| int posix_memalign(void** pp, size_t alignment, size_t n); |
| Allocates a chunk of n bytes, aligned in accord with the alignment |
| argument. Differs from memalign only in that it (1) assigns the |
| allocated memory to *pp rather than returning it, (2) fails and |
| returns EINVAL if the alignment is not a power of two (3) fails and |
| returns ENOMEM if memory cannot be allocated. |
| */ |
| DLMALLOC_EXPORT int dlposix_memalign(void**, size_t, size_t); |
| |
| /* |
| valloc(size_t n); |
| Equivalent to memalign(pagesize, n), where pagesize is the page |
| size of the system. If the pagesize is unknown, 4096 is used. |
| */ |
| DLMALLOC_EXPORT void* dlvalloc(size_t); |
| |
| /* |
| mallopt(int parameter_number, int parameter_value) |
| Sets tunable parameters The format is to provide a |
| (parameter-number, parameter-value) pair. mallopt then sets the |
| corresponding parameter to the argument value if it can (i.e., so |
| long as the value is meaningful), and returns 1 if successful else |
| 0. To workaround the fact that mallopt is specified to use int, |
| not size_t parameters, the value -1 is specially treated as the |
| maximum unsigned size_t value. |
| |
| SVID/XPG/ANSI defines four standard param numbers for mallopt, |
| normally defined in malloc.h. None of these are use in this malloc, |
| so setting them has no effect. But this malloc also supports other |
| options in mallopt. See below for details. Briefly, supported |
| parameters are as follows (listed defaults are for "typical" |
| configurations). |
| |
| Symbol param # default allowed param values |
| M_TRIM_THRESHOLD -1 2*1024*1024 any (-1 disables) |
| M_GRANULARITY -2 page size any power of 2 >= page size |
| M_MMAP_THRESHOLD -3 256*1024 any (or 0 if no MMAP support) |
| */ |
| DLMALLOC_EXPORT int dlmallopt(int, int); |
| |
| /* |
| malloc_footprint(); |
| Returns the number of bytes obtained from the system. The total |
| number of bytes allocated by malloc, realloc etc., is less than this |
| value. Unlike mallinfo, this function returns only a precomputed |
| result, so can be called frequently to monitor memory consumption. |
| Even if locks are otherwise defined, this function does not use them, |
| so results might not be up to date. |
| */ |
| DLMALLOC_EXPORT size_t dlmalloc_footprint(void); |
| |
| /* |
| malloc_max_footprint(); |
| Returns the maximum number of bytes obtained from the system. This |
| value will be greater than current footprint if deallocated space |
| has been reclaimed by the system. The peak number of bytes allocated |
| by malloc, realloc etc., is less than this value. Unlike mallinfo, |
| this function returns only a precomputed result, so can be called |
| frequently to monitor memory consumption. Even if locks are |
| otherwise defined, this function does not use them, so results might |
| not be up to date. |
| */ |
| DLMALLOC_EXPORT size_t dlmalloc_max_footprint(void); |
| |
| /* |
| malloc_footprint_limit(); |
| Returns the number of bytes that the heap is allowed to obtain from |
| the system, returning the last value returned by |
| malloc_set_footprint_limit, or the maximum size_t value if |
| never set. The returned value reflects a permission. There is no |
| guarantee that this number of bytes can actually be obtained from |
| the system. |
| */ |
| DLMALLOC_EXPORT size_t dlmalloc_footprint_limit(); |
| |
| /* |
| malloc_set_footprint_limit(); |
| Sets the maximum number of bytes to obtain from the system, causing |
| failure returns from malloc and related functions upon attempts to |
| exceed this value. The argument value may be subject to page |
| rounding to an enforceable limit; this actual value is returned. |
| Using an argument of the maximum possible size_t effectively |
| disables checks. If the argument is less than or equal to the |
| current malloc_footprint, then all future allocations that require |
| additional system memory will fail. However, invocation cannot |
| retroactively deallocate existing used memory. |
| */ |
| DLMALLOC_EXPORT size_t dlmalloc_set_footprint_limit(size_t bytes); |
| |
| #if MALLOC_INSPECT_ALL |
| /* |
| malloc_inspect_all(void(*handler)(void *start, |
| void *end, |
| size_t used_bytes, |
| void* callback_arg), |
| void* arg); |
| Traverses the heap and calls the given handler for each managed |
| region, skipping all bytes that are (or may be) used for bookkeeping |
| purposes. Traversal does not include include chunks that have been |
| directly memory mapped. Each reported region begins at the start |
| address, and continues up to but not including the end address. The |
| first used_bytes of the region contain allocated data. If |
| used_bytes is zero, the region is unallocated. The handler is |
| invoked with the given callback argument. If locks are defined, they |
| are held during the entire traversal. It is a bad idea to invoke |
| other malloc functions from within the handler. |
| |
| For example, to count the number of in-use chunks with size greater |
| than 1000, you could write: |
| static int count = 0; |
| void count_chunks(void* start, void* end, size_t used, void* arg) { |
| if (used >= 1000) ++count; |
| } |
| then: |
| malloc_inspect_all(count_chunks, NULL); |
| |
| malloc_inspect_all is compiled only if MALLOC_INSPECT_ALL is defined. |
| */ |
| DLMALLOC_EXPORT void dlmalloc_inspect_all(void(*handler)(void*, void *, size_t, void*), |
| void* arg); |
| |
| #endif /* MALLOC_INSPECT_ALL */ |
| |
| #if !NO_MALLINFO |
| /* |
| mallinfo() |
| Returns (by copy) a struct containing various summary statistics: |
| |
| arena: current total non-mmapped bytes allocated from system |
| ordblks: the number of free chunks |
| smblks: always zero. |
| hblks: current number of mmapped regions |
| hblkhd: total bytes held in mmapped regions |
| usmblks: the maximum total allocated space. This will be greater |
| than current total if trimming has occurred. |
| fsmblks: always zero |
| uordblks: current total allocated space (normal or mmapped) |
| fordblks: total free space |
| keepcost: the maximum number of bytes that could ideally be released |
| back to system via malloc_trim. ("ideally" means that |
| it ignores page restrictions etc.) |
| |
| Because these fields are ints, but internal bookkeeping may |
| be kept as longs, the reported values may wrap around zero and |
| thus be inaccurate. |
| */ |
| DLMALLOC_EXPORT struct dlmallinfo dlmallinfo(void); |
| #endif /* NO_MALLINFO */ |
| |
| /* |
| independent_calloc(size_t n_elements, size_t element_size, void* chunks[]); |
| |
| independent_calloc is similar to calloc, but instead of returning a |
| single cleared space, it returns an array of pointers to n_elements |
| independent elements that can hold contents of size elem_size, each |
| of which starts out cleared, and can be independently freed, |
| realloc'ed etc. The elements are guaranteed to be adjacently |
| allocated (this is not guaranteed to occur with multiple callocs or |
| mallocs), which may also improve cache locality in some |
| applications. |
| |
| The "chunks" argument is optional (i.e., may be null, which is |
| probably the most typical usage). If it is null, the returned array |
| is itself dynamically allocated and should also be freed when it is |
| no longer needed. Otherwise, the chunks array must be of at least |
| n_elements in length. It is filled in with the pointers to the |
| chunks. |
| |
| In either case, independent_calloc returns this pointer array, or |
| null if the allocation failed. If n_elements is zero and "chunks" |
| is null, it returns a chunk representing an array with zero elements |
| (which should be freed if not wanted). |
| |
| Each element must be freed when it is no longer needed. This can be |
| done all at once using bulk_free. |
| |
| independent_calloc simplifies and speeds up implementations of many |
| kinds of pools. It may also be useful when constructing large data |
| structures that initially have a fixed number of fixed-sized nodes, |
| but the number is not known at compile time, and some of the nodes |
| may later need to be freed. For example: |
| |
| struct Node { int item; struct Node* next; }; |
| |
| struct Node* build_list() { |
| struct Node** pool; |
| int n = read_number_of_nodes_needed(); |
| if (n <= 0) return 0; |
| pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0); |
| if (pool == 0) die(); |
| // organize into a linked list... |
| struct Node* first = pool[0]; |
| for (i = 0; i < n-1; ++i) |
| pool[i]->next = pool[i+1]; |
| free(pool); // Can now free the array (or not, if it is needed later) |
| return first; |
| } |
| */ |
| DLMALLOC_EXPORT void** dlindependent_calloc(size_t, size_t, void**); |
| |
| /* |
| independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]); |
| |
| independent_comalloc allocates, all at once, a set of n_elements |
| chunks with sizes indicated in the "sizes" array. It returns |
| an array of pointers to these elements, each of which can be |
| independently freed, realloc'ed etc. The elements are guaranteed to |
| be adjacently allocated (this is not guaranteed to occur with |
| multiple callocs or mallocs), which may also improve cache locality |
| in some applications. |
| |
| The "chunks" argument is optional (i.e., may be null). If it is null |
| the returned array is itself dynamically allocated and should also |
| be freed when it is no longer needed. Otherwise, the chunks array |
| must be of at least n_elements in length. It is filled in with the |
| pointers to the chunks. |
| |
| In either case, independent_comalloc returns this pointer array, or |
| null if the allocation failed. If n_elements is zero and chunks is |
| null, it returns a chunk representing an array with zero elements |
| (which should be freed if not wanted). |
| |
| Each element must be freed when it is no longer needed. This can be |
| done all at once using bulk_free. |
| |
| independent_comallac differs from independent_calloc in that each |
| element may have a different size, and also that it does not |
| automatically clear elements. |
| |
| independent_comalloc can be used to speed up allocation in cases |
| where several structs or objects must always be allocated at the |
| same time. For example: |
| |
| struct Head { ... } |
| struct Foot { ... } |
| |
| void send_message(char* msg) { |
| int msglen = strlen(msg); |
| size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) }; |
| void* chunks[3]; |
| if (independent_comalloc(3, sizes, chunks) == 0) |
| die(); |
| struct Head* head = (struct Head*)(chunks[0]); |
| char* body = (char*)(chunks[1]); |
| struct Foot* foot = (struct Foot*)(chunks[2]); |
| // ... |
| } |
| |
| In general though, independent_comalloc is worth using only for |
| larger values of n_elements. For small values, you probably won't |
| detect enough difference from series of malloc calls to bother. |
| |
| Overuse of independent_comalloc can increase overall memory usage, |
| since it cannot reuse existing noncontiguous small chunks that |
| might be available for some of the elements. |
| */ |
| DLMALLOC_EXPORT void** dlindependent_comalloc(size_t, size_t*, void**); |
| |
| /* |
| bulk_free(void* array[], size_t n_elements) |
| Frees and clears (sets to null) each non-null pointer in the given |
| array. This is likely to be faster than freeing them one-by-one. |
| If footers are used, pointers that have been allocated in different |
| mspaces are not freed or cleared, and the count of all such pointers |
| is returned. For large arrays of pointers with poor locality, it |
| may be worthwhile to sort this array before calling bulk_free. |
| */ |
| DLMALLOC_EXPORT size_t dlbulk_free(void**, size_t n_elements); |
| |
| /* |
| pvalloc(size_t n); |
| Equivalent to valloc(minimum-page-that-holds(n)), that is, |
| round up n to nearest pagesize. |
| */ |
| DLMALLOC_EXPORT void* dlpvalloc(size_t); |
| |
| /* |
| malloc_trim(size_t pad); |
| |
| If possible, gives memory back to the system (via negative arguments |
| to sbrk) if there is unused memory at the `high' end of the malloc |
| pool or in unused MMAP segments. You can call this after freeing |
| large blocks of memory to potentially reduce the system-level memory |
| requirements of a program. However, it cannot guarantee to reduce |
| memory. Under some allocation patterns, some large free blocks of |
| memory will be locked between two used chunks, so they cannot be |
| given back to the system. |
| |
| The `pad' argument to malloc_trim represents the amount of free |
| trailing space to leave untrimmed. If this argument is zero, only |
| the minimum amount of memory to maintain internal data structures |
| will be left. Non-zero arguments can be supplied to maintain enough |
| trailing space to service future expected allocations without having |
| to re-obtain memory from the system. |
| |
| Malloc_trim returns 1 if it actually released any memory, else 0. |
| */ |
| DLMALLOC_EXPORT int dlmalloc_trim(size_t); |
| |
| /* |
| malloc_stats(); |
| Prints on stderr the amount of space obtained 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), 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. Because it includes |
| alignment wastage as being in use, this figure may be greater than |
| zero even when no user-level chunks are allocated. |
| |
| The reported current and maximum system memory can be inaccurate if |
| a program makes other calls to system memory allocation functions |
| (normally sbrk) outside of malloc. |
| |
| malloc_stats prints only the most commonly interesting statistics. |
| More information can be obtained by calling mallinfo. |
| */ |
| DLMALLOC_EXPORT void dlmalloc_stats(void); |
| |
| /* |
| malloc_usable_size(void* p); |
| |
| Returns the number of bytes you can actually use in |
| an allocated chunk, which may be more than you requested (although |
| often not) due to alignment and minimum size constraints. |
| You can use this many bytes without worrying about |
| overwriting other allocated objects. This is not a particularly great |
| programming practice. malloc_usable_size can be more useful in |
| debugging and assertions, for example: |
| |
| p = malloc(n); |
| assert(malloc_usable_size(p) >= 256); |
| */ |
| size_t dlmalloc_usable_size(void*); |
| |
| #endif /* ONLY_MSPACES */ |
| |
| #if MSPACES |
| |
| /* |
| mspace is an opaque type representing an independent |
| region of space that supports mspace_malloc, etc. |
| */ |
| typedef void* mspace; |
| |
| /* |
| create_mspace creates and returns a new independent space with the |
| given initial capacity, or, if 0, the default granularity size. It |
| returns null if there is no system memory available to create the |
| space. If argument locked is non-zero, the space uses a separate |
| lock to control access. The capacity of the space will grow |
| dynamically as needed to service mspace_malloc requests. You can |
| control the sizes of incremental increases of this space by |
| compiling with a different DEFAULT_GRANULARITY or dynamically |
| setting with mallopt(M_GRANULARITY, value). |
| */ |
| DLMALLOC_EXPORT mspace create_mspace(size_t capacity, int locked); |
| |
| /* |
| destroy_mspace destroys the given space, and attempts to return all |
| of its memory back to the system, returning the total number of |
| bytes freed. After destruction, the results of access to all memory |
| used by the space become undefined. |
| */ |
| DLMALLOC_EXPORT size_t destroy_mspace(mspace msp); |
| |
| /* |
| create_mspace_with_base uses the memory supplied as the initial base |
| of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this |
| space is used for bookkeeping, so the capacity must be at least this |
| large. (Otherwise 0 is returned.) When this initial space is |
| exhausted, additional memory will be obtained from the system. |
| Destroying this space will deallocate all additionally allocated |
| space (if possible) but not the initial base. |
| */ |
| DLMALLOC_EXPORT mspace create_mspace_with_base(void* base, size_t capacity, int locked); |
| |
| /* |
| mspace_track_large_chunks controls whether requests for large chunks |
| are allocated in their own untracked mmapped regions, separate from |
| others in this mspace. By default large chunks are not tracked, |
| which reduces fragmentation. However, such chunks are not |
| necessarily released to the system upon destroy_mspace. Enabling |
| tracking by setting to true may increase fragmentation, but avoids |
| leakage when relying on destroy_mspace to release all memory |
| allocated using this space. The function returns the previous |
| setting. |
| */ |
| DLMALLOC_EXPORT int mspace_track_large_chunks(mspace msp, int enable); |
| |
| |
| /* |
| mspace_malloc behaves as malloc, but operates within |
| the given space. |
| */ |
| DLMALLOC_EXPORT void* mspace_malloc(mspace msp, size_t bytes); |
| |
| /* |
| mspace_free behaves as free, but operates within |
| the given space. |
| |
| If compiled with FOOTERS==1, mspace_free is not actually needed. |
| free may be called instead of mspace_free because freed chunks from |
| any space are handled by their originating spaces. |
| */ |
| DLMALLOC_EXPORT void mspace_free(mspace msp, void* mem); |
| |
| /* |
| mspace_realloc behaves as realloc, but operates within |
| the given space. |
| |
| If compiled with FOOTERS==1, mspace_realloc is not actually |
| needed. realloc may be called instead of mspace_realloc because |
| realloced chunks from any space are handled by their originating |
| spaces. |
| */ |
| DLMALLOC_EXPORT void* mspace_realloc(mspace msp, void* mem, size_t newsize); |
| |
| /* |
| mspace_calloc behaves as calloc, but operates within |
| the given space. |
| */ |
| DLMALLOC_EXPORT void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size); |
| |
| /* |
| mspace_memalign behaves as memalign, but operates within |
| the given space. |
| */ |
| DLMALLOC_EXPORT void* mspace_memalign(mspace msp, size_t alignment, size_t bytes); |
| |
| /* |
| mspace_independent_calloc behaves as independent_calloc, but |
| operates within the given space. |
| */ |
| DLMALLOC_EXPORT void** mspace_independent_calloc(mspace msp, size_t n_elements, |
| size_t elem_size, void* chunks[]); |
| |
| /* |
| mspace_independent_comalloc behaves as independent_comalloc, but |
| operates within the given space. |
| */ |
| DLMALLOC_EXPORT void** mspace_independent_comalloc(mspace msp, size_t n_elements, |
| size_t sizes[], void* chunks[]); |
| |
| /* |
| mspace_footprint() returns the number of bytes obtained from the |
| system for this space. |
| */ |
| DLMALLOC_EXPORT size_t mspace_footprint(mspace msp); |
| |
| /* |
| mspace_max_footprint() returns the peak number of bytes obtained from the |
| system for this space. |
| */ |
| DLMALLOC_EXPORT size_t mspace_max_footprint(mspace msp); |
| |
| |
| #if !NO_MALLINFO |
| /* |
| mspace_mallinfo behaves as mallinfo, but reports properties of |
| the given space. |
| */ |
| DLMALLOC_EXPORT struct dlmallinfo mspace_mallinfo(mspace msp); |
| #endif /* NO_MALLINFO */ |
| |
| /* |
| malloc_usable_size(void* p) behaves the same as malloc_usable_size; |
| */ |
| DLMALLOC_EXPORT size_t mspace_usable_size(const void* mem); |
| |
| /* |
| mspace_malloc_stats behaves as malloc_stats, but reports |
| properties of the given space. |
| */ |
| DLMALLOC_EXPORT void mspace_malloc_stats(mspace msp); |
| |
| /* |
| mspace_trim behaves as malloc_trim, but |
| operates within the given space. |
| */ |
| DLMALLOC_EXPORT int mspace_trim(mspace msp, size_t pad); |
| |
| /* |
| An alias for mallopt. |
| */ |
| DLMALLOC_EXPORT int mspace_mallopt(int, int); |
| |
| DLMALLOC_EXPORT void* mspace_get_aligned (mspace msp, |
| unsigned long n_user_data_bytes, |
| unsigned long align, |
| unsigned long align_offset); |
| |
| DLMALLOC_EXPORT int mspace_is_heap_object (mspace msp, void *p); |
| |
| DLMALLOC_EXPORT void mspace_get_address_and_size (mspace msp, char **addrp, size_t *sizep); |
| DLMALLOC_EXPORT void mspace_put (mspace msp, void *p); |
| DLMALLOC_EXPORT void mspace_put_no_offset (mspace msp, void *p); |
| DLMALLOC_EXPORT size_t mspace_usable_size_with_delta (const void *p); |
| DLMALLOC_EXPORT void mspace_disable_expand (mspace msp); |
| DLMALLOC_EXPORT void *mspace_least_addr (mspace msp); |
| DLMALLOC_EXPORT void mheap_get_trace (uword offset, uword size); |
| DLMALLOC_EXPORT void mheap_put_trace (uword offset, uword size); |
| DLMALLOC_EXPORT int mspace_enable_disable_trace (mspace msp, int enable); |
| DLMALLOC_EXPORT int mspace_is_traced (mspace msp); |
| |
| #endif /* MSPACES */ |
| |
| #ifdef __cplusplus |
| } /* end of extern "C" */ |
| #endif /* __cplusplus */ |
| |
| /* |
| ======================================================================== |
| To make a fully customizable malloc.h header file, cut everything |
| above this line, put into file malloc.h, edit to suit, and #include it |
| on the next line, as well as in programs that use this malloc. |
| ======================================================================== |
| */ |