2 This is a version (aka dlmalloc) of malloc/free/realloc written by
3 Doug Lea and released to the public domain, as explained at
4 http://creativecommons.org/publicdomain/zero/1.0/ Send questions,
5 comments, complaints, performance data, etc to dl@cs.oswego.edu
8 #include <vppinfra/dlmalloc.h>
9 #include <vppinfra/sanitizer.h>
11 /*------------------------------ internal #includes ---------------------- */
14 #pragma warning( disable : 4146 ) /* no "unsigned" warnings */
17 #include <stdio.h> /* for printing in malloc_stats */
18 #endif /* NO_MALLOC_STATS */
20 #include <errno.h> /* for MALLOC_FAILURE_ACTION */
21 #endif /* LACKS_ERRNO_H */
23 #if DLM_ABORT_ON_ASSERT_FAILURE
25 #define assert(x) if(!(x)) DLM_ABORT
26 #else /* DLM_ABORT_ON_ASSERT_FAILURE */
28 #endif /* DLM_ABORT_ON_ASSERT_FAILURE */
35 #if !defined(WIN32) && !defined(LACKS_TIME_H)
36 #include <time.h> /* for magic initialization */
38 #ifndef LACKS_STDLIB_H
39 #include <stdlib.h> /* for abort() */
40 #endif /* LACKS_STDLIB_H */
41 #ifndef LACKS_STRING_H
42 #include <string.h> /* for memset etc */
43 #endif /* LACKS_STRING_H */
45 #ifndef LACKS_STRINGS_H
46 #include <strings.h> /* for ffs */
47 #endif /* LACKS_STRINGS_H */
48 #endif /* USE_BUILTIN_FFS */
50 #ifndef LACKS_SYS_MMAN_H
51 /* On some versions of linux, mremap decl in mman.h needs __USE_GNU set */
52 #if (defined(linux) && !defined(__USE_GNU))
54 #include <sys/mman.h> /* for mmap */
57 #include <sys/mman.h> /* for mmap */
59 #endif /* LACKS_SYS_MMAN_H */
62 #endif /* LACKS_FCNTL_H */
63 #endif /* HAVE_MMAP */
64 #ifndef LACKS_UNISTD_H
65 #include <unistd.h> /* for sbrk, sysconf */
66 #else /* LACKS_UNISTD_H */
67 #if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
68 extern void* sbrk(ptrdiff_t);
69 #endif /* FreeBSD etc */
70 #endif /* LACKS_UNISTD_H */
72 /* Declarations for locking */
75 #if defined (__SVR4) && defined (__sun) /* solaris */
77 #elif !defined(LACKS_SCHED_H)
79 #endif /* solaris or LACKS_SCHED_H */
80 #if (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0) || !USE_SPIN_LOCKS
82 #endif /* USE_RECURSIVE_LOCKS ... */
83 #elif defined(_MSC_VER)
85 /* These are already defined on AMD64 builds */
88 #endif /* __cplusplus */
89 LONG __cdecl _InterlockedCompareExchange(LONG volatile *Dest, LONG Exchange, LONG Comp);
90 LONG __cdecl _InterlockedExchange(LONG volatile *Target, LONG Value);
93 #endif /* __cplusplus */
95 #pragma intrinsic (_InterlockedCompareExchange)
96 #pragma intrinsic (_InterlockedExchange)
97 #define interlockedcompareexchange _InterlockedCompareExchange
98 #define interlockedexchange _InterlockedExchange
99 #elif defined(WIN32) && defined(__GNUC__)
100 #define interlockedcompareexchange(a, b, c) __sync_val_compare_and_swap(a, c, b)
101 #define interlockedexchange __sync_lock_test_and_set
103 #else /* USE_LOCKS */
104 #endif /* USE_LOCKS */
107 #define LOCK_AT_FORK 0
110 /* Declarations for bit scanning on win32 */
111 #if defined(_MSC_VER) && _MSC_VER>=1300
112 #ifndef BitScanForward /* Try to avoid pulling in WinNT.h */
115 #endif /* __cplusplus */
116 unsigned char _BitScanForward(unsigned long *index, unsigned long mask);
117 unsigned char _BitScanReverse(unsigned long *index, unsigned long mask);
120 #endif /* __cplusplus */
122 #define BitScanForward _BitScanForward
123 #define BitScanReverse _BitScanReverse
124 #pragma intrinsic(_BitScanForward)
125 #pragma intrinsic(_BitScanReverse)
126 #endif /* BitScanForward */
127 #endif /* defined(_MSC_VER) && _MSC_VER>=1300 */
130 #ifndef malloc_getpagesize
131 # ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */
132 # ifndef _SC_PAGE_SIZE
133 # define _SC_PAGE_SIZE _SC_PAGESIZE
136 # ifdef _SC_PAGE_SIZE
137 # define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
139 # if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
140 extern size_t getpagesize();
141 # define malloc_getpagesize getpagesize()
143 # ifdef WIN32 /* use supplied emulation of getpagesize */
144 # define malloc_getpagesize getpagesize()
146 # ifndef LACKS_SYS_PARAM_H
147 # include <sys/param.h>
149 # ifdef EXEC_PAGESIZE
150 # define malloc_getpagesize EXEC_PAGESIZE
154 # define malloc_getpagesize NBPG
156 # define malloc_getpagesize (NBPG * CLSIZE)
160 # define malloc_getpagesize NBPC
163 # define malloc_getpagesize PAGESIZE
164 # else /* just guess */
165 # define malloc_getpagesize ((size_t)4096U)
176 /* ------------------- size_t and alignment properties -------------------- */
178 /* The byte and bit size of a size_t */
179 #define SIZE_T_SIZE (sizeof(size_t))
180 #define SIZE_T_BITSIZE (sizeof(size_t) << 3)
182 /* Some constants coerced to size_t */
183 /* Annoying but necessary to avoid errors on some platforms */
184 #define SIZE_T_ZERO ((size_t)0)
185 #define SIZE_T_ONE ((size_t)1)
186 #define SIZE_T_TWO ((size_t)2)
187 #define SIZE_T_FOUR ((size_t)4)
188 #define TWO_SIZE_T_SIZES (SIZE_T_SIZE<<1)
189 #define FOUR_SIZE_T_SIZES (SIZE_T_SIZE<<2)
190 #define SIX_SIZE_T_SIZES (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES)
191 #define HALF_MAX_SIZE_T (MAX_SIZE_T / 2U)
193 /* The bit mask value corresponding to MALLOC_ALIGNMENT */
194 #define CHUNK_ALIGN_MASK (MALLOC_ALIGNMENT - SIZE_T_ONE)
196 /* True if address a has acceptable alignment */
197 #define is_aligned(A) (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0)
199 /* the number of bytes to offset an address to align it */
200 #define align_offset(A)\
201 ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\
202 ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK))
204 /* -------------------------- MMAP preliminaries ------------------------- */
207 If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and
208 checks to fail so compiler optimizer can delete code rather than
209 using so many "#if"s.
213 /* MORECORE and MMAP must return MFAIL on failure */
214 #define MFAIL ((void*)(MAX_SIZE_T))
215 #define CMFAIL ((char*)(MFAIL)) /* defined for convenience */
220 #define MUNMAP_DEFAULT(a, s) munmap((a), (s))
221 #define MMAP_PROT (PROT_READ|PROT_WRITE)
222 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
223 #define MAP_ANONYMOUS MAP_ANON
224 #endif /* MAP_ANON */
226 #define MMAP_FLAGS (MAP_PRIVATE|MAP_ANONYMOUS)
227 #define MMAP_DEFAULT(s) mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
228 #else /* MAP_ANONYMOUS */
230 Nearly all versions of mmap support MAP_ANONYMOUS, so the following
231 is unlikely to be needed, but is supplied just in case.
233 #define MMAP_FLAGS (MAP_PRIVATE)
234 static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */
235 #define MMAP_DEFAULT(s) ((dev_zero_fd < 0) ? \
236 (dev_zero_fd = open("/dev/zero", O_RDWR), \
237 mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \
238 mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0))
239 #endif /* MAP_ANONYMOUS */
241 #define DIRECT_MMAP_DEFAULT(s) MMAP_DEFAULT(s)
245 /* Win32 MMAP via VirtualAlloc */
246 static FORCEINLINE void* win32mmap(size_t size) {
247 void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
248 return (ptr != 0)? ptr: MFAIL;
251 /* For direct MMAP, use MEM_TOP_DOWN to minimize interference */
252 static FORCEINLINE void* win32direct_mmap(size_t size) {
253 void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN,
255 return (ptr != 0)? ptr: MFAIL;
258 /* This function supports releasing coalesed segments */
259 static FORCEINLINE int win32munmap(void* ptr, size_t size) {
260 MEMORY_BASIC_INFORMATION minfo;
261 char* cptr = (char*)ptr;
263 if (VirtualQuery(cptr, &minfo, sizeof(minfo)) == 0)
265 if (minfo.BaseAddress != cptr || minfo.AllocationBase != cptr ||
266 minfo.State != MEM_COMMIT || minfo.RegionSize > size)
268 if (VirtualFree(cptr, 0, MEM_RELEASE) == 0)
270 cptr += minfo.RegionSize;
271 size -= minfo.RegionSize;
276 #define MMAP_DEFAULT(s) win32mmap(s)
277 #define MUNMAP_DEFAULT(a, s) win32munmap((a), (s))
278 #define DIRECT_MMAP_DEFAULT(s) win32direct_mmap(s)
280 #endif /* HAVE_MMAP */
284 #define MREMAP_DEFAULT(addr, osz, nsz, mv) mremap((addr), (osz), (nsz), (mv))
286 #endif /* HAVE_MREMAP */
289 * Define CALL_MORECORE
293 #define CALL_MORECORE(S) MORECORE(S)
295 #define CALL_MORECORE(S) MORECORE_DEFAULT(S)
296 #endif /* MORECORE */
297 #else /* HAVE_MORECORE */
298 #define CALL_MORECORE(S) MFAIL
299 #endif /* HAVE_MORECORE */
302 * Define CALL_MMAP/CALL_MUNMAP/CALL_DIRECT_MMAP
305 #define USE_MMAP_BIT (SIZE_T_ONE)
308 #define CALL_MMAP(s) MMAP(s)
310 #define CALL_MMAP(s) MMAP_DEFAULT(s)
313 #define CALL_MUNMAP(a, s) MUNMAP((a), (s))
315 #define CALL_MUNMAP(a, s) MUNMAP_DEFAULT((a), (s))
318 #define CALL_DIRECT_MMAP(s) DIRECT_MMAP(s)
319 #else /* DIRECT_MMAP */
320 #define CALL_DIRECT_MMAP(s) DIRECT_MMAP_DEFAULT(s)
321 #endif /* DIRECT_MMAP */
322 #else /* HAVE_MMAP */
323 #define USE_MMAP_BIT (SIZE_T_ZERO)
325 #define MMAP(s) MFAIL
326 #define MUNMAP(a, s) (-1)
327 #define DIRECT_MMAP(s) MFAIL
328 #define CALL_DIRECT_MMAP(s) DIRECT_MMAP(s)
329 #define CALL_MMAP(s) MMAP(s)
330 #define CALL_MUNMAP(a, s) MUNMAP((a), (s))
331 #endif /* HAVE_MMAP */
336 #if HAVE_MMAP && HAVE_MREMAP
338 #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP((addr), (osz), (nsz), (mv))
340 #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP_DEFAULT((addr), (osz), (nsz), (mv))
342 #else /* HAVE_MMAP && HAVE_MREMAP */
343 #define CALL_MREMAP(addr, osz, nsz, mv) MFAIL
344 #endif /* HAVE_MMAP && HAVE_MREMAP */
346 /* mstate bit set if contiguous morecore disabled or failed */
347 #define USE_NONCONTIGUOUS_BIT (4U)
349 /* mstate bit set if no expansion allowed */
350 #define USE_NOEXPAND_BIT (8U)
352 /* trace allocations if set */
353 #define USE_TRACE_BIT (16U)
355 /* segment bit set in create_mspace_with_base */
356 #define EXTERN_BIT (8U)
359 /* --------------------------- Lock preliminaries ------------------------ */
362 When locks are defined, there is one global lock, plus
365 The global lock_ensures that mparams.magic and other unique
366 mparams values are initialized only once. It also protects
367 sequences of calls to MORECORE. In many cases sys_alloc requires
368 two calls, that should not be interleaved with calls by other
369 threads. This does not protect against direct calls to MORECORE
370 by other threads not using this lock, so there is still code to
371 cope the best we can on interference.
373 Per-mspace locks surround calls to malloc, free, etc.
374 By default, locks are simple non-reentrant mutexes.
376 Because lock-protected regions generally have bounded times, it is
377 OK to use the supplied simple spinlocks. Spinlocks are likely to
378 improve performance for lightly contended applications, but worsen
379 performance under heavy contention.
381 If USE_LOCKS is > 1, the definitions of lock routines here are
382 bypassed, in which case you will need to define the type MLOCK_T,
383 and at least INITIAL_LOCK, DESTROY_LOCK, ACQUIRE_LOCK, RELEASE_LOCK
384 and TRY_LOCK. You must also declare a
385 static MLOCK_T malloc_global_mutex = { initialization values };.
390 #define USE_LOCK_BIT (0U)
391 #define INITIAL_LOCK(l) (0)
392 #define DESTROY_LOCK(l) (0)
393 #define ACQUIRE_MALLOC_GLOBAL_LOCK()
394 #define RELEASE_MALLOC_GLOBAL_LOCK()
398 /* ----------------------- User-defined locks ------------------------ */
399 /* Define your own lock implementation here */
400 /* #define INITIAL_LOCK(lk) ... */
401 /* #define DESTROY_LOCK(lk) ... */
402 /* #define ACQUIRE_LOCK(lk) ... */
403 /* #define RELEASE_LOCK(lk) ... */
404 /* #define TRY_LOCK(lk) ... */
405 /* static MLOCK_T malloc_global_mutex = ... */
409 /* First, define CAS_LOCK and CLEAR_LOCK on ints */
410 /* Note CAS_LOCK defined to return 0 on success */
412 #if defined(__GNUC__)&& (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
413 #define CAS_LOCK(sl) __sync_lock_test_and_set(sl, 1)
414 #define CLEAR_LOCK(sl) __sync_lock_release(sl)
416 #elif (defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)))
417 /* Custom spin locks for older gcc on x86 */
418 static FORCEINLINE int x86_cas_lock(int *sl) {
422 __asm__ __volatile__ ("lock; cmpxchgl %1, %2"
424 : "r" (val), "m" (*(sl)), "0"(cmp)
429 static FORCEINLINE void x86_clear_lock(int* sl) {
433 __asm__ __volatile__ ("lock; xchgl %0, %1"
435 : "m" (*(sl)), "0"(prev)
439 #define CAS_LOCK(sl) x86_cas_lock(sl)
440 #define CLEAR_LOCK(sl) x86_clear_lock(sl)
442 #else /* Win32 MSC */
443 #define CAS_LOCK(sl) interlockedexchange(sl, (LONG)1)
444 #define CLEAR_LOCK(sl) interlockedexchange (sl, (LONG)0)
446 #endif /* ... gcc spins locks ... */
448 /* How to yield for a spin lock */
449 #define SPINS_PER_YIELD 63
450 #if defined(_MSC_VER)
451 #define SLEEP_EX_DURATION 50 /* delay for yield/sleep */
452 #define SPIN_LOCK_YIELD SleepEx(SLEEP_EX_DURATION, FALSE)
453 #elif defined (__SVR4) && defined (__sun) /* solaris */
454 #define SPIN_LOCK_YIELD thr_yield();
455 #elif !defined(LACKS_SCHED_H)
456 #define SPIN_LOCK_YIELD sched_yield();
458 #define SPIN_LOCK_YIELD
459 #endif /* ... yield ... */
461 #if !defined(USE_RECURSIVE_LOCKS) || USE_RECURSIVE_LOCKS == 0
462 /* Plain spin locks use single word (embedded in malloc_states) */
464 static int spin_acquire_lock(int *sl) {
466 while (*(volatile int *)sl != 0 || CAS_LOCK(sl)) {
467 if ((++spins & SPINS_PER_YIELD) == 0) {
475 #define TRY_LOCK(sl) !CAS_LOCK(sl)
476 #define RELEASE_LOCK(sl) CLEAR_LOCK(sl)
477 #define ACQUIRE_LOCK(sl) (CAS_LOCK(sl)? spin_acquire_lock(sl) : 0)
478 #define INITIAL_LOCK(sl) (*sl = 0)
479 #define DESTROY_LOCK(sl) (0)
480 static MLOCK_T malloc_global_mutex = 0;
482 #else /* USE_RECURSIVE_LOCKS */
483 /* types for lock owners */
485 #define THREAD_ID_T DWORD
486 #define CURRENT_THREAD GetCurrentThreadId()
487 #define EQ_OWNER(X,Y) ((X) == (Y))
490 Note: the following assume that pthread_t is a type that can be
491 initialized to (casted) zero. If this is not the case, you will need to
492 somehow redefine these or not use spin locks.
494 #define THREAD_ID_T pthread_t
495 #define CURRENT_THREAD pthread_self()
496 #define EQ_OWNER(X,Y) pthread_equal(X, Y)
499 struct malloc_recursive_lock {
502 THREAD_ID_T threadid;
505 #define MLOCK_T struct malloc_recursive_lock
506 static MLOCK_T malloc_global_mutex = { 0, 0, (THREAD_ID_T)0};
508 static FORCEINLINE void recursive_release_lock(MLOCK_T *lk) {
515 static FORCEINLINE int recursive_acquire_lock(MLOCK_T *lk) {
516 THREAD_ID_T mythreadid = CURRENT_THREAD;
519 if (*((volatile int *)(&lk->sl)) == 0) {
520 if (!CAS_LOCK(&lk->sl)) {
521 lk->threadid = mythreadid;
526 else if (EQ_OWNER(lk->threadid, mythreadid)) {
530 if ((++spins & SPINS_PER_YIELD) == 0) {
536 static FORCEINLINE int recursive_try_lock(MLOCK_T *lk) {
537 THREAD_ID_T mythreadid = CURRENT_THREAD;
538 if (*((volatile int *)(&lk->sl)) == 0) {
539 if (!CAS_LOCK(&lk->sl)) {
540 lk->threadid = mythreadid;
545 else if (EQ_OWNER(lk->threadid, mythreadid)) {
552 #define RELEASE_LOCK(lk) recursive_release_lock(lk)
553 #define TRY_LOCK(lk) recursive_try_lock(lk)
554 #define ACQUIRE_LOCK(lk) recursive_acquire_lock(lk)
555 #define INITIAL_LOCK(lk) ((lk)->threadid = (THREAD_ID_T)0, (lk)->sl = 0, (lk)->c = 0)
556 #define DESTROY_LOCK(lk) (0)
557 #endif /* USE_RECURSIVE_LOCKS */
559 #elif defined(WIN32) /* Win32 critical sections */
560 #define MLOCK_T CRITICAL_SECTION
561 #define ACQUIRE_LOCK(lk) (EnterCriticalSection(lk), 0)
562 #define RELEASE_LOCK(lk) LeaveCriticalSection(lk)
563 #define TRY_LOCK(lk) TryEnterCriticalSection(lk)
564 #define INITIAL_LOCK(lk) (!InitializeCriticalSectionAndSpinCount((lk), 0x80000000|4000))
565 #define DESTROY_LOCK(lk) (DeleteCriticalSection(lk), 0)
566 #define NEED_GLOBAL_LOCK_INIT
568 static MLOCK_T malloc_global_mutex;
569 static volatile LONG malloc_global_mutex_status;
571 /* Use spin loop to initialize global lock */
572 static void init_malloc_global_mutex() {
574 long stat = malloc_global_mutex_status;
577 /* transition to < 0 while initializing, then to > 0) */
579 interlockedcompareexchange(&malloc_global_mutex_status, (LONG)-1, (LONG)0) == 0) {
580 InitializeCriticalSection(&malloc_global_mutex);
581 interlockedexchange(&malloc_global_mutex_status, (LONG)1);
588 #else /* pthreads-based locks */
589 #define MLOCK_T pthread_mutex_t
590 #define ACQUIRE_LOCK(lk) pthread_mutex_lock(lk)
591 #define RELEASE_LOCK(lk) pthread_mutex_unlock(lk)
592 #define TRY_LOCK(lk) (!pthread_mutex_trylock(lk))
593 #define INITIAL_LOCK(lk) pthread_init_lock(lk)
594 #define DESTROY_LOCK(lk) pthread_mutex_destroy(lk)
596 #if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0 && defined(linux) && !defined(PTHREAD_MUTEX_RECURSIVE)
597 /* Cope with old-style linux recursive lock initialization by adding */
598 /* skipped internal declaration from pthread.h */
599 extern int pthread_mutexattr_setkind_np __P ((pthread_mutexattr_t *__attr,
601 #define PTHREAD_MUTEX_RECURSIVE PTHREAD_MUTEX_RECURSIVE_NP
602 #define pthread_mutexattr_settype(x,y) pthread_mutexattr_setkind_np(x,y)
603 #endif /* USE_RECURSIVE_LOCKS ... */
605 static MLOCK_T malloc_global_mutex = PTHREAD_MUTEX_INITIALIZER;
607 static int pthread_init_lock (MLOCK_T *lk) {
608 pthread_mutexattr_t attr;
609 if (pthread_mutexattr_init(&attr)) return 1;
610 #if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0
611 if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)) return 1;
613 if (pthread_mutex_init(lk, &attr)) return 1;
614 if (pthread_mutexattr_destroy(&attr)) return 1;
618 #endif /* ... lock types ... */
620 /* Common code for all lock types */
621 #define USE_LOCK_BIT (2U)
623 #ifndef ACQUIRE_MALLOC_GLOBAL_LOCK
624 #define ACQUIRE_MALLOC_GLOBAL_LOCK() ACQUIRE_LOCK(&malloc_global_mutex);
627 #ifndef RELEASE_MALLOC_GLOBAL_LOCK
628 #define RELEASE_MALLOC_GLOBAL_LOCK() RELEASE_LOCK(&malloc_global_mutex);
631 #endif /* USE_LOCKS */
633 /* ----------------------- Chunk representations ------------------------ */
636 (The following includes lightly edited explanations by Colin Plumb.)
638 The malloc_chunk declaration below is misleading (but accurate and
639 necessary). It declares a "view" into memory allowing access to
640 necessary fields at known offsets from a given base.
642 Chunks of memory are maintained using a `boundary tag' method as
643 originally described by Knuth. (See the paper by Paul Wilson
644 ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such
645 techniques.) Sizes of free chunks are stored both in the front of
646 each chunk and at the end. This makes consolidating fragmented
647 chunks into bigger chunks fast. The head fields also hold bits
648 representing whether chunks are free or in use.
650 Here are some pictures to make it clearer. They are "exploded" to
651 show that the state of a chunk can be thought of as extending from
652 the high 31 bits of the head field of its header through the
653 prev_foot and PINUSE_BIT bit of the following chunk header.
655 A chunk that's in use looks like:
657 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
658 | Size of previous chunk (if P = 0) |
659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
660 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
661 | Size of this chunk 1| +-+
662 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
668 +- size - sizeof(size_t) available payload bytes -+
672 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|
674 | Size of next chunk (may or may not be in use) | +-+
675 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
677 And if it's free, it looks like this:
680 | User payload (must be in use, or we would have merged!) |
681 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
682 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
683 | Size of this chunk 0| +-+
684 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
686 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
688 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
690 +- size - sizeof(struct chunk) unused bytes -+
692 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
693 | Size of this chunk |
694 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
695 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|
696 | Size of next chunk (must be in use, or we would have merged)| +-+
697 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
701 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
704 Note that since we always merge adjacent free chunks, the chunks
705 adjacent to a free chunk must be in use.
707 Given a pointer to a chunk (which can be derived trivially from the
708 payload pointer) we can, in O(1) time, find out whether the adjacent
709 chunks are free, and if so, unlink them from the lists that they
710 are on and merge them with the current chunk.
712 Chunks always begin on even word boundaries, so the mem portion
713 (which is returned to the user) is also on an even word boundary, and
714 thus at least double-word aligned.
716 The P (PINUSE_BIT) bit, stored in the unused low-order bit of the
717 chunk size (which is always a multiple of two words), is an in-use
718 bit for the *previous* chunk. If that bit is *clear*, then the
719 word before the current chunk size contains the previous chunk
720 size, and can be used to find the front of the previous chunk.
721 The very first chunk allocated always has this bit set, preventing
722 access to non-existent (or non-owned) memory. If pinuse is set for
723 any given chunk, then you CANNOT determine the size of the
724 previous chunk, and might even get a memory addressing fault when
727 The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of
728 the chunk size redundantly records whether the current chunk is
729 inuse (unless the chunk is mmapped). This redundancy enables usage
730 checks within free and realloc, and reduces indirection when freeing
731 and consolidating chunks.
733 Each freshly allocated chunk must have both cinuse and pinuse set.
734 That is, each allocated chunk borders either a previously allocated
735 and still in-use chunk, or the base of its memory arena. This is
736 ensured by making all allocations from the `lowest' part of any
737 found chunk. Further, no free chunk physically borders another one,
738 so each free chunk is known to be preceded and followed by either
739 inuse chunks or the ends of memory.
741 Note that the `foot' of the current chunk is actually represented
742 as the prev_foot of the NEXT chunk. This makes it easier to
743 deal with alignments etc but can be very confusing when trying
744 to extend or adapt this code.
746 The exceptions to all this are
748 1. The special chunk `top' is the top-most available chunk (i.e.,
749 the one bordering the end of available memory). It is treated
750 specially. Top is never included in any bin, is used only if
751 no other chunk is available, and is released back to the
752 system if it is very large (see M_TRIM_THRESHOLD). In effect,
753 the top chunk is treated as larger (and thus less well
754 fitting) than any other available chunk. The top chunk
755 doesn't update its trailing size field since there is no next
756 contiguous chunk that would have to index off it. However,
757 space is still allocated for it (TOP_FOOT_SIZE) to enable
758 separation or merging when space is extended.
760 3. Chunks allocated via mmap, have both cinuse and pinuse bits
761 cleared in their head fields. Because they are allocated
762 one-by-one, each must carry its own prev_foot field, which is
763 also used to hold the offset this chunk has within its mmapped
764 region, which is needed to preserve alignment. Each mmapped
765 chunk is trailed by the first two fields of a fake next-chunk
766 for sake of usage checks.
770 struct malloc_chunk {
771 size_t prev_foot; /* Size of previous chunk (if free). */
772 size_t head; /* Size and inuse bits. */
773 struct malloc_chunk* fd; /* double links -- used only if free. */
774 struct malloc_chunk* bk;
777 typedef struct malloc_chunk mchunk;
778 typedef struct malloc_chunk* mchunkptr;
779 typedef struct malloc_chunk* sbinptr; /* The type of bins of chunks */
780 typedef unsigned int bindex_t; /* Described below */
781 typedef unsigned int binmap_t; /* Described below */
782 typedef unsigned int flag_t; /* The type of various bit flag sets */
784 /* ------------------- Chunks sizes and alignments ----------------------- */
786 #define MCHUNK_SIZE (sizeof(mchunk))
789 #define CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
791 #define CHUNK_OVERHEAD (SIZE_T_SIZE)
794 /* MMapped chunks need a second word of overhead ... */
795 #define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
796 /* ... and additional padding for fake next-chunk at foot */
797 #define MMAP_FOOT_PAD (FOUR_SIZE_T_SIZES)
799 /* The smallest size we can malloc is an aligned minimal chunk */
800 #define MIN_CHUNK_SIZE\
801 ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
803 /* conversion from malloc headers to user pointers, and back */
804 #define chunk2mem(p) ((void*)((char*)(p) + TWO_SIZE_T_SIZES))
805 #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
806 /* chunk associated with aligned address A */
807 #define align_as_chunk(A) (mchunkptr)((A) + align_offset(chunk2mem(A)))
809 /* Bounds on request (not chunk) sizes. */
810 #define MAX_REQUEST ((-MIN_CHUNK_SIZE) << 2)
811 #define MIN_REQUEST (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)
813 /* pad request bytes into a usable size */
814 #define pad_request(req) \
815 (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
817 /* pad request, checking for minimum (but not maximum) */
818 #define request2size(req) \
819 (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))
822 /* ------------------ Operations on head and foot fields ----------------- */
825 The head field of a chunk is or'ed with PINUSE_BIT when previous
826 adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in
827 use, unless mmapped, in which case both bits are cleared.
829 FLAG4_BIT is not used by this malloc, but might be useful in extensions.
832 #define PINUSE_BIT (SIZE_T_ONE)
833 #define CINUSE_BIT (SIZE_T_TWO)
834 #define FLAG4_BIT (SIZE_T_FOUR)
835 #define INUSE_BITS (PINUSE_BIT|CINUSE_BIT)
836 #define FLAG_BITS (PINUSE_BIT|CINUSE_BIT|FLAG4_BIT)
838 /* Head value for fenceposts */
839 #define FENCEPOST_HEAD (INUSE_BITS|SIZE_T_SIZE)
841 /* extraction of fields from head words */
842 #define cinuse(p) ((p)->head & CINUSE_BIT)
843 #define pinuse(p) ((p)->head & PINUSE_BIT)
844 #define flag4inuse(p) ((p)->head & FLAG4_BIT)
845 #define is_inuse(p) (((p)->head & INUSE_BITS) != PINUSE_BIT)
846 #define is_mmapped(p) (((p)->head & INUSE_BITS) == 0)
848 #define chunksize(p) ((p)->head & ~(FLAG_BITS))
850 #define clear_pinuse(p) ((p)->head &= ~PINUSE_BIT)
851 #define set_flag4(p) ((p)->head |= FLAG4_BIT)
852 #define clear_flag4(p) ((p)->head &= ~FLAG4_BIT)
854 /* Treat space at ptr +/- offset as a chunk */
855 #define chunk_plus_offset(p, s) ((mchunkptr)(((char*)(p)) + (s)))
856 #define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s)))
858 /* Ptr to next or previous physical malloc_chunk. */
859 #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~FLAG_BITS)))
860 #define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) ))
862 /* extract next chunk's pinuse bit */
863 #define next_pinuse(p) ((next_chunk(p)->head) & PINUSE_BIT)
865 /* Get/set size at footer */
866 #define get_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot)
867 #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s))
869 /* Set size, pinuse bit, and foot */
870 #define set_size_and_pinuse_of_free_chunk(p, s)\
871 ((p)->head = (s|PINUSE_BIT), set_foot(p, s))
873 /* Set size, pinuse bit, foot, and clear next pinuse */
874 #define set_free_with_pinuse(p, s, n)\
875 (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s))
877 /* Get the internal overhead associated with chunk p */
878 #define overhead_for(p)\
879 (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD)
881 /* Return true if malloced space is not necessarily cleared */
883 #define calloc_must_clear(p) (!is_mmapped(p))
884 #else /* MMAP_CLEARS */
885 #define calloc_must_clear(p) (1)
886 #endif /* MMAP_CLEARS */
888 /* ---------------------- Overlaid data structures ----------------------- */
891 When chunks are not in use, they are treated as nodes of either
894 "Small" chunks are stored in circular doubly-linked lists, and look
897 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
898 | Size of previous chunk |
899 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
900 `head:' | Size of chunk, in bytes |P|
901 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
902 | Forward pointer to next chunk in list |
903 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
904 | Back pointer to previous chunk in list |
905 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
906 | Unused space (may be 0 bytes long) .
909 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
910 `foot:' | Size of chunk, in bytes |
911 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
913 Larger chunks are kept in a form of bitwise digital trees (aka
914 tries) keyed on chunksizes. Because malloc_tree_chunks are only for
915 free chunks greater than 256 bytes, their size doesn't impose any
916 constraints on user chunk sizes. Each node looks like:
918 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
919 | Size of previous chunk |
920 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
921 `head:' | Size of chunk, in bytes |P|
922 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
923 | Forward pointer to next chunk of same size |
924 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
925 | Back pointer to previous chunk of same size |
926 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
927 | Pointer to left child (child[0]) |
928 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
929 | Pointer to right child (child[1]) |
930 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
931 | Pointer to parent |
932 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
933 | bin index of this chunk |
934 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
937 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
938 `foot:' | Size of chunk, in bytes |
939 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
941 Each tree holding treenodes is a tree of unique chunk sizes. Chunks
942 of the same size are arranged in a circularly-linked list, with only
943 the oldest chunk (the next to be used, in our FIFO ordering)
944 actually in the tree. (Tree members are distinguished by a non-null
945 parent pointer.) If a chunk with the same size an an existing node
946 is inserted, it is linked off the existing node using pointers that
947 work in the same way as fd/bk pointers of small chunks.
949 Each tree contains a power of 2 sized range of chunk sizes (the
950 smallest is 0x100 <= x < 0x180), which is is divided in half at each
951 tree level, with the chunks in the smaller half of the range (0x100
952 <= x < 0x140 for the top nose) in the left subtree and the larger
953 half (0x140 <= x < 0x180) in the right subtree. This is, of course,
954 done by inspecting individual bits.
956 Using these rules, each node's left subtree contains all smaller
957 sizes than its right subtree. However, the node at the root of each
958 subtree has no particular ordering relationship to either. (The
959 dividing line between the subtree sizes is based on trie relation.)
960 If we remove the last chunk of a given size from the interior of the
961 tree, we need to replace it with a leaf node. The tree ordering
962 rules permit a node to be replaced by any leaf below it.
964 The smallest chunk in a tree (a common operation in a best-fit
965 allocator) can be found by walking a path to the leftmost leaf in
966 the tree. Unlike a usual binary tree, where we follow left child
967 pointers until we reach a null, here we follow the right child
968 pointer any time the left one is null, until we reach a leaf with
969 both child pointers null. The smallest chunk in the tree will be
970 somewhere along that path.
972 The worst case number of steps to add, find, or remove a node is
973 bounded by the number of bits differentiating chunks within
974 bins. Under current bin calculations, this ranges from 6 up to 21
975 (for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case
976 is of course much better.
979 struct malloc_tree_chunk {
980 /* The first four fields must be compatible with malloc_chunk */
983 struct malloc_tree_chunk* fd;
984 struct malloc_tree_chunk* bk;
986 struct malloc_tree_chunk* child[2];
987 struct malloc_tree_chunk* parent;
991 typedef struct malloc_tree_chunk tchunk;
992 typedef struct malloc_tree_chunk* tchunkptr;
993 typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */
995 /* A little helper macro for trees */
996 #define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1])
998 /* ----------------------------- Segments -------------------------------- */
1001 Each malloc space may include non-contiguous segments, held in a
1002 list headed by an embedded malloc_segment record representing the
1003 top-most space. Segments also include flags holding properties of
1004 the space. Large chunks that are directly allocated by mmap are not
1005 included in this list. They are instead independently created and
1006 destroyed without otherwise keeping track of them.
1008 Segment management mainly comes into play for spaces allocated by
1009 MMAP. Any call to MMAP might or might not return memory that is
1010 adjacent to an existing segment. MORECORE normally contiguously
1011 extends the current space, so this space is almost always adjacent,
1012 which is simpler and faster to deal with. (This is why MORECORE is
1013 used preferentially to MMAP when both are available -- see
1014 sys_alloc.) When allocating using MMAP, we don't use any of the
1015 hinting mechanisms (inconsistently) supported in various
1016 implementations of unix mmap, or distinguish reserving from
1017 committing memory. Instead, we just ask for space, and exploit
1018 contiguity when we get it. It is probably possible to do
1019 better than this on some systems, but no general scheme seems
1020 to be significantly better.
1022 Management entails a simpler variant of the consolidation scheme
1023 used for chunks to reduce fragmentation -- new adjacent memory is
1024 normally prepended or appended to an existing segment. However,
1025 there are limitations compared to chunk consolidation that mostly
1026 reflect the fact that segment processing is relatively infrequent
1027 (occurring only when getting memory from system) and that we
1028 don't expect to have huge numbers of segments:
1030 * Segments are not indexed, so traversal requires linear scans. (It
1031 would be possible to index these, but is not worth the extra
1032 overhead and complexity for most programs on most platforms.)
1033 * New segments are only appended to old ones when holding top-most
1034 memory; if they cannot be prepended to others, they are held in
1037 Except for the top-most segment of an mstate, each segment record
1038 is kept at the tail of its segment. Segments are added by pushing
1039 segment records onto the list headed by &mstate.seg for the
1042 Segment flags control allocation/merge/deallocation policies:
1043 * If EXTERN_BIT set, then we did not allocate this segment,
1044 and so should not try to deallocate or merge with others.
1045 (This currently holds only for the initial segment passed
1046 into create_mspace_with_base.)
1047 * If USE_MMAP_BIT set, the segment may be merged with
1048 other surrounding mmapped segments and trimmed/de-allocated
1050 * If neither bit is set, then the segment was obtained using
1051 MORECORE so can be merged with surrounding MORECORE'd segments
1052 and deallocated/trimmed using MORECORE with negative arguments.
1055 struct malloc_segment {
1056 char* base; /* base address */
1057 size_t size; /* allocated size */
1058 struct malloc_segment* next; /* ptr to next segment */
1059 flag_t sflags; /* mmap and extern flag */
1062 #define is_mmapped_segment(S) ((S)->sflags & USE_MMAP_BIT)
1063 #define is_extern_segment(S) ((S)->sflags & EXTERN_BIT)
1065 typedef struct malloc_segment msegment;
1066 typedef struct malloc_segment* msegmentptr;
1068 /* ---------------------------- malloc_state ----------------------------- */
1071 A malloc_state holds all of the bookkeeping for a space.
1072 The main fields are:
1075 The topmost chunk of the currently active segment. Its size is
1076 cached in topsize. The actual size of topmost space is
1077 topsize+TOP_FOOT_SIZE, which includes space reserved for adding
1078 fenceposts and segment records if necessary when getting more
1079 space from the system. The size at which to autotrim top is
1080 cached from mparams in trim_check, except that it is disabled if
1083 Designated victim (dv)
1084 This is the preferred chunk for servicing small requests that
1085 don't have exact fits. It is normally the chunk split off most
1086 recently to service another small request. Its size is cached in
1087 dvsize. The link fields of this chunk are not maintained since it
1088 is not kept in a bin.
1091 An array of bin headers for free chunks. These bins hold chunks
1092 with sizes less than MIN_LARGE_SIZE bytes. Each bin contains
1093 chunks of all the same size, spaced 8 bytes apart. To simplify
1094 use in double-linked lists, each bin header acts as a malloc_chunk
1095 pointing to the real first node, if it exists (else pointing to
1096 itself). This avoids special-casing for headers. But to avoid
1097 waste, we allocate only the fd/bk pointers of bins, and then use
1098 repositioning tricks to treat these as the fields of a chunk.
1101 Treebins are pointers to the roots of trees holding a range of
1102 sizes. There are 2 equally spaced treebins for each power of two
1103 from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything
1107 There is one bit map for small bins ("smallmap") and one for
1108 treebins ("treemap). Each bin sets its bit when non-empty, and
1109 clears the bit when empty. Bit operations are then used to avoid
1110 bin-by-bin searching -- nearly all "search" is done without ever
1111 looking at bins that won't be selected. The bit maps
1112 conservatively use 32 bits per map word, even if on 64bit system.
1113 For a good description of some of the bit-based techniques used
1114 here, see Henry S. Warren Jr's book "Hacker's Delight" (and
1115 supplement at http://hackersdelight.org/). Many of these are
1116 intended to reduce the branchiness of paths through malloc etc, as
1117 well as to reduce the number of memory locations read or written.
1120 A list of segments headed by an embedded malloc_segment record
1121 representing the initial space.
1123 Address check support
1124 The least_addr field is the least address ever obtained from
1125 MORECORE or MMAP. Attempted frees and reallocs of any address less
1126 than this are trapped (unless INSECURE is defined).
1129 A cross-check field that should always hold same value as mparams.magic.
1131 Max allowed footprint
1132 The maximum allowed bytes to allocate from system (zero means no limit)
1135 Bits recording whether to use MMAP, locks, or contiguous MORECORE
1138 Each space keeps track of current and maximum system memory
1139 obtained via MORECORE or MMAP.
1142 Fields holding the amount of unused topmost memory that should trigger
1143 trimming, and a counter to force periodic scanning to release unused
1144 non-topmost segments.
1147 If USE_LOCKS is defined, the "mutex" lock is acquired and released
1148 around every public call using this mspace.
1151 A void* pointer and a size_t field that can be used to help implement
1152 extensions to this malloc.
1155 /* Bin types, widths and sizes */
1156 #define NSMALLBINS (32U)
1157 #define NTREEBINS (32U)
1158 #define SMALLBIN_SHIFT (3U)
1159 #define SMALLBIN_WIDTH (SIZE_T_ONE << SMALLBIN_SHIFT)
1160 #define TREEBIN_SHIFT (8U)
1161 #define MIN_LARGE_SIZE (SIZE_T_ONE << TREEBIN_SHIFT)
1162 #define MAX_SMALL_SIZE (MIN_LARGE_SIZE - SIZE_T_ONE)
1163 #define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD)
1165 struct malloc_state {
1174 size_t release_checks;
1176 mchunkptr smallbins[(NSMALLBINS+1)*2];
1177 tbinptr treebins[NTREEBINS];
1179 size_t max_footprint;
1180 size_t footprint_limit; /* zero means no limit */
1183 MLOCK_T mutex; /* locate lock among fields that rarely change */
1184 #endif /* USE_LOCKS */
1186 void* extp; /* Unused but available for extensions */
1190 typedef struct malloc_state* mstate;
1192 /* ------------- Global malloc_state and malloc_params ------------------- */
1195 malloc_params holds global properties, including those that can be
1196 dynamically set using mallopt. There is a single instance, mparams,
1197 initialized in init_mparams. Note that the non-zeroness of "magic"
1198 also serves as an initialization flag.
1201 struct malloc_params {
1205 size_t mmap_threshold;
1206 size_t trim_threshold;
1207 flag_t default_mflags;
1210 static struct malloc_params mparams;
1212 /* Ensure mparams initialized */
1213 #define ensure_initialization() (void)(mparams.magic != 0 || init_mparams())
1217 /* The global malloc_state used for all non-"mspace" calls */
1218 static struct malloc_state _gm_;
1220 #define is_global(M) ((M) == &_gm_)
1222 #endif /* !ONLY_MSPACES */
1224 #define is_initialized(M) ((M)->top != 0)
1226 /* -------------------------- system alloc setup ------------------------- */
1228 /* Operations on mflags */
1230 #define use_lock(M) ((M)->mflags & USE_LOCK_BIT)
1231 #define enable_lock(M) ((M)->mflags |= USE_LOCK_BIT)
1233 #define disable_lock(M) ((M)->mflags &= ~USE_LOCK_BIT)
1235 #define disable_lock(M)
1238 #define use_mmap(M) ((M)->mflags & USE_MMAP_BIT)
1239 #define enable_mmap(M) ((M)->mflags |= USE_MMAP_BIT)
1241 #define disable_mmap(M) ((M)->mflags &= ~USE_MMAP_BIT)
1243 #define disable_mmap(M)
1246 #define use_noncontiguous(M) ((M)->mflags & USE_NONCONTIGUOUS_BIT)
1247 #define disable_contiguous(M) ((M)->mflags |= USE_NONCONTIGUOUS_BIT)
1248 #define use_noexpand(M) ((M)->mflags & USE_NOEXPAND_BIT)
1249 #define disable_expand(M) ((M)->mflags |= USE_NOEXPAND_BIT)
1250 #define use_trace(M) ((M)->mflags & USE_TRACE_BIT)
1251 #define enable_trace(M) ((M)->mflags |= USE_TRACE_BIT)
1252 #define disable_trace(M) ((M)->mflags |= USE_TRACE_BIT)
1254 #define set_lock(M,L)\
1255 ((M)->mflags = (L)?\
1256 ((M)->mflags | USE_LOCK_BIT) :\
1257 ((M)->mflags & ~USE_LOCK_BIT))
1259 /* page-align a size */
1260 #define page_align(S)\
1261 (((S) + (mparams.page_size - SIZE_T_ONE)) & ~(mparams.page_size - SIZE_T_ONE))
1263 /* granularity-align a size */
1264 #define granularity_align(S)\
1265 (((S) + (mparams.granularity - SIZE_T_ONE))\
1266 & ~(mparams.granularity - SIZE_T_ONE))
1269 /* For mmap, use granularity alignment on windows, else page-align */
1271 #define mmap_align(S) granularity_align(S)
1273 #define mmap_align(S) page_align(S)
1276 /* For sys_alloc, enough padding to ensure can malloc request on success */
1277 #define SYS_ALLOC_PADDING (TOP_FOOT_SIZE + MALLOC_ALIGNMENT)
1279 #define is_page_aligned(S)\
1280 (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0)
1281 #define is_granularity_aligned(S)\
1282 (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0)
1284 /* True if segment S holds address A */
1285 #define segment_holds(S, A)\
1286 ((char*)(A) >= S->base && (char*)(A) < S->base + S->size)
1288 /* Return segment holding given address */
1289 CLIB_NOSANITIZE_ADDR
1290 static msegmentptr segment_holding(mstate m, char* addr) {
1291 msegmentptr sp = &m->seg;
1293 if (addr >= sp->base && addr < sp->base + sp->size)
1295 if ((sp = sp->next) == 0)
1300 /* Return true if segment contains a segment link */
1301 CLIB_NOSANITIZE_ADDR
1302 static int has_segment_link(mstate m, msegmentptr ss) {
1303 msegmentptr sp = &m->seg;
1305 if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size)
1307 if ((sp = sp->next) == 0)
1312 #ifndef MORECORE_CANNOT_TRIM
1313 #define should_trim(M,s) ((s) > (M)->trim_check)
1314 #else /* MORECORE_CANNOT_TRIM */
1315 #define should_trim(M,s) (0)
1316 #endif /* MORECORE_CANNOT_TRIM */
1319 TOP_FOOT_SIZE is padding at the end of a segment, including space
1320 that may be needed to place segment records and fenceposts when new
1321 noncontiguous segments are added.
1323 #define TOP_FOOT_SIZE\
1324 (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE)
1327 /* ------------------------------- Hooks -------------------------------- */
1330 PREACTION should be defined to return 0 on success, and nonzero on
1331 failure. If you are not using locking, you can redefine these to do
1336 #define PREACTION(M) ((use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0)
1337 #define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); }
1338 #else /* USE_LOCKS */
1341 #define PREACTION(M) (0)
1342 #endif /* PREACTION */
1345 #define POSTACTION(M)
1346 #endif /* POSTACTION */
1348 #endif /* USE_LOCKS */
1351 CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses.
1352 USAGE_ERROR_ACTION is triggered on detected bad frees and
1353 reallocs. The argument p is an address that might have triggered the
1354 fault. It is ignored by the two predefined actions, but might be
1355 useful in custom actions that try to help diagnose errors.
1358 #if PROCEED_ON_ERROR
1360 /* A count of the number of corruption errors causing resets */
1361 int malloc_corruption_error_count;
1363 /* default corruption action */
1364 static void reset_on_error(mstate m);
1366 #define CORRUPTION_ERROR_ACTION(m) reset_on_error(m)
1367 #define USAGE_ERROR_ACTION(m, p)
1369 #else /* PROCEED_ON_ERROR */
1371 #ifndef CORRUPTION_ERROR_ACTION
1372 #define CORRUPTION_ERROR_ACTION(m) DLM_ABORT
1373 #endif /* CORRUPTION_ERROR_ACTION */
1375 #ifndef USAGE_ERROR_ACTION
1376 #define USAGE_ERROR_ACTION(m,p) DLM_ABORT
1377 #endif /* USAGE_ERROR_ACTION */
1379 #endif /* PROCEED_ON_ERROR */
1382 /* -------------------------- Debugging setup ---------------------------- */
1386 #define check_free_chunk(M,P)
1387 #define check_inuse_chunk(M,P)
1388 #define check_malloced_chunk(M,P,N)
1389 #define check_mmapped_chunk(M,P)
1390 #define check_malloc_state(M)
1391 #define check_top_chunk(M,P)
1394 #define check_free_chunk(M,P) do_check_free_chunk(M,P)
1395 #define check_inuse_chunk(M,P) do_check_inuse_chunk(M,P)
1396 #define check_top_chunk(M,P) do_check_top_chunk(M,P)
1397 #define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N)
1398 #define check_mmapped_chunk(M,P) do_check_mmapped_chunk(M,P)
1399 #define check_malloc_state(M) do_check_malloc_state(M)
1401 static void do_check_any_chunk(mstate m, mchunkptr p);
1402 static void do_check_top_chunk(mstate m, mchunkptr p);
1403 static void do_check_mmapped_chunk(mstate m, mchunkptr p);
1404 static void do_check_inuse_chunk(mstate m, mchunkptr p);
1405 static void do_check_free_chunk(mstate m, mchunkptr p);
1406 static void do_check_malloced_chunk(mstate m, void* mem, size_t s);
1407 static void do_check_tree(mstate m, tchunkptr t);
1408 static void do_check_treebin(mstate m, bindex_t i);
1409 static void do_check_smallbin(mstate m, bindex_t i);
1410 static void do_check_malloc_state(mstate m);
1411 static int bin_find(mstate m, mchunkptr x);
1412 static size_t traverse_and_check(mstate m);
1415 /* ---------------------------- Indexing Bins ---------------------------- */
1417 #define is_small(s) (((s) >> SMALLBIN_SHIFT) < NSMALLBINS)
1418 #define small_index(s) (bindex_t)((s) >> SMALLBIN_SHIFT)
1419 #define small_index2size(i) ((i) << SMALLBIN_SHIFT)
1420 #define MIN_SMALL_INDEX (small_index(MIN_CHUNK_SIZE))
1422 /* addressing by index. See above about smallbin repositioning */
1423 #define smallbin_at(M, i) ((sbinptr)((char*)&((M)->smallbins[(i)<<1])))
1424 #define treebin_at(M,i) (&((M)->treebins[i]))
1426 /* assign tree index for size S to variable I. Use x86 asm if possible */
1427 #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
1428 #define compute_tree_index(S, I)\
1430 unsigned int X = S >> TREEBIN_SHIFT;\
1433 else if (X > 0xFFFF)\
1436 unsigned int K = (unsigned) sizeof(X)*__CHAR_BIT__ - 1 - (unsigned) __builtin_clz(X); \
1437 I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
1441 #elif defined (__INTEL_COMPILER)
1442 #define compute_tree_index(S, I)\
1444 size_t X = S >> TREEBIN_SHIFT;\
1447 else if (X > 0xFFFF)\
1450 unsigned int K = _bit_scan_reverse (X); \
1451 I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
1455 #elif defined(_MSC_VER) && _MSC_VER>=1300
1456 #define compute_tree_index(S, I)\
1458 size_t X = S >> TREEBIN_SHIFT;\
1461 else if (X > 0xFFFF)\
1465 _BitScanReverse((DWORD *) &K, (DWORD) X);\
1466 I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
1471 #define compute_tree_index(S, I)\
1473 size_t X = S >> TREEBIN_SHIFT;\
1476 else if (X > 0xFFFF)\
1479 unsigned int Y = (unsigned int)X;\
1480 unsigned int N = ((Y - 0x100) >> 16) & 8;\
1481 unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\
1483 N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\
1484 K = 14 - N + ((Y <<= K) >> 15);\
1485 I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\
1490 /* Bit representing maximum resolved size in a treebin at i */
1491 #define bit_for_tree_index(i) \
1492 (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2)
1494 /* Shift placing maximum resolved bit in a treebin at i as sign bit */
1495 #define leftshift_for_tree_index(i) \
1496 ((i == NTREEBINS-1)? 0 : \
1497 ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2)))
1499 /* The size of the smallest chunk held in bin with index i */
1500 #define minsize_for_tree_index(i) \
1501 ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) | \
1502 (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1)))
1505 /* ------------------------ Operations on bin maps ----------------------- */
1507 /* bit corresponding to given index */
1508 #define idx2bit(i) ((binmap_t)(1) << (i))
1510 /* Mark/Clear bits with given index */
1511 #define mark_smallmap(M,i) ((M)->smallmap |= idx2bit(i))
1512 #define clear_smallmap(M,i) ((M)->smallmap &= ~idx2bit(i))
1513 #define smallmap_is_marked(M,i) ((M)->smallmap & idx2bit(i))
1515 #define mark_treemap(M,i) ((M)->treemap |= idx2bit(i))
1516 #define clear_treemap(M,i) ((M)->treemap &= ~idx2bit(i))
1517 #define treemap_is_marked(M,i) ((M)->treemap & idx2bit(i))
1519 /* isolate the least set bit of a bitmap */
1520 #define least_bit(x) ((x) & -(x))
1522 /* mask with all bits to left of least bit of x on */
1523 #define left_bits(x) ((x<<1) | -(x<<1))
1525 /* mask with all bits to left of or equal to least bit of x on */
1526 #define same_or_left_bits(x) ((x) | -(x))
1528 /* index corresponding to given bit. Use x86 asm if possible */
1530 #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
1531 #define compute_bit2idx(X, I)\
1534 J = __builtin_ctz(X); \
1538 #elif defined (__INTEL_COMPILER)
1539 #define compute_bit2idx(X, I)\
1542 J = _bit_scan_forward (X); \
1546 #elif defined(_MSC_VER) && _MSC_VER>=1300
1547 #define compute_bit2idx(X, I)\
1550 _BitScanForward((DWORD *) &J, X);\
1554 #elif USE_BUILTIN_FFS
1555 #define compute_bit2idx(X, I) I = ffs(X)-1
1558 #define compute_bit2idx(X, I)\
1560 unsigned int Y = X - 1;\
1561 unsigned int K = Y >> (16-4) & 16;\
1562 unsigned int N = K; Y >>= K;\
1563 N += K = Y >> (8-3) & 8; Y >>= K;\
1564 N += K = Y >> (4-2) & 4; Y >>= K;\
1565 N += K = Y >> (2-1) & 2; Y >>= K;\
1566 N += K = Y >> (1-0) & 1; Y >>= K;\
1567 I = (bindex_t)(N + Y);\
1572 /* ----------------------- Runtime Check Support ------------------------- */
1575 For security, the main invariant is that malloc/free/etc never
1576 writes to a static address other than malloc_state, unless static
1577 malloc_state itself has been corrupted, which cannot occur via
1578 malloc (because of these checks). In essence this means that we
1579 believe all pointers, sizes, maps etc held in malloc_state, but
1580 check all of those linked or offsetted from other embedded data
1581 structures. These checks are interspersed with main code in a way
1582 that tends to minimize their run-time cost.
1584 When FOOTERS is defined, in addition to range checking, we also
1585 verify footer fields of inuse chunks, which can be used guarantee
1586 that the mstate controlling malloc/free is intact. This is a
1587 streamlined version of the approach described by William Robertson
1588 et al in "Run-time Detection of Heap-based Overflows" LISA'03
1589 http://www.usenix.org/events/lisa03/tech/robertson.html The footer
1590 of an inuse chunk holds the xor of its mstate and a random seed,
1591 that is checked upon calls to free() and realloc(). This is
1592 (probabilistically) unguessable from outside the program, but can be
1593 computed by any code successfully malloc'ing any chunk, so does not
1594 itself provide protection against code that has already broken
1595 security through some other means. Unlike Robertson et al, we
1596 always dynamically check addresses of all offset chunks (previous,
1597 next, etc). This turns out to be cheaper than relying on hashes.
1601 /* Check if address a is at least as high as any from MORECORE or MMAP */
1602 #define ok_address(M, a) ((char*)(a) >= (M)->least_addr)
1603 /* Check if address of next chunk n is higher than base chunk p */
1604 #define ok_next(p, n) ((char*)(p) < (char*)(n))
1605 /* Check if p has inuse status */
1606 #define ok_inuse(p) is_inuse(p)
1607 /* Check if p has its pinuse bit on */
1608 #define ok_pinuse(p) pinuse(p)
1610 #else /* !INSECURE */
1611 #define ok_address(M, a) (1)
1612 #define ok_next(b, n) (1)
1613 #define ok_inuse(p) (1)
1614 #define ok_pinuse(p) (1)
1615 #endif /* !INSECURE */
1617 #if (FOOTERS && !INSECURE)
1618 /* Check if (alleged) mstate m has expected magic field */
1619 CLIB_NOSANITIZE_ADDR
1621 ok_magic (const mstate m)
1623 return (m->magic == mparams.magic);
1625 #else /* (FOOTERS && !INSECURE) */
1626 #define ok_magic(M) (1)
1627 #endif /* (FOOTERS && !INSECURE) */
1629 /* In gcc, use __builtin_expect to minimize impact of checks */
1631 #if defined(__GNUC__) && __GNUC__ >= 3
1632 #define RTCHECK(e) __builtin_expect(e, 1)
1634 #define RTCHECK(e) (e)
1636 #else /* !INSECURE */
1637 #define RTCHECK(e) (1)
1638 #endif /* !INSECURE */
1640 /* macros to set up inuse chunks with or without footers */
1644 #define mark_inuse_foot(M,p,s)
1646 /* Macros for setting head/foot of non-mmapped chunks */
1648 /* Set cinuse bit and pinuse bit of next chunk */
1649 #define set_inuse(M,p,s)\
1650 ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
1651 ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
1653 /* Set cinuse and pinuse of this chunk and pinuse of next chunk */
1654 #define set_inuse_and_pinuse(M,p,s)\
1655 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
1656 ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
1658 /* Set size, cinuse and pinuse bit of this chunk */
1659 #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
1660 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT))
1664 /* Set foot of inuse chunk to be xor of mstate and seed */
1665 #define mark_inuse_foot(M,p,s)\
1666 (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic))
1668 #define get_mstate_for(p)\
1669 ((mstate)(((mchunkptr)((char*)(p) +\
1670 (chunksize(p))))->prev_foot ^ mparams.magic))
1672 #define set_inuse(M,p,s)\
1673 ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
1674 (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \
1675 mark_inuse_foot(M,p,s))
1677 #define set_inuse_and_pinuse(M,p,s)\
1678 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
1679 (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\
1680 mark_inuse_foot(M,p,s))
1682 #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
1683 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
1684 mark_inuse_foot(M, p, s))
1686 #endif /* !FOOTERS */
1688 /* ---------------------------- setting mparams -------------------------- */
1691 static void pre_fork(void) { ACQUIRE_LOCK(&(gm)->mutex); }
1692 static void post_fork_parent(void) { RELEASE_LOCK(&(gm)->mutex); }
1693 static void post_fork_child(void) { INITIAL_LOCK(&(gm)->mutex); }
1694 #endif /* LOCK_AT_FORK */
1696 /* Initialize mparams */
1697 static int init_mparams(void) {
1698 #ifdef NEED_GLOBAL_LOCK_INIT
1699 if (malloc_global_mutex_status <= 0)
1700 init_malloc_global_mutex();
1703 ACQUIRE_MALLOC_GLOBAL_LOCK();
1704 if (mparams.magic == 0) {
1710 psize = malloc_getpagesize;
1711 gsize = ((DEFAULT_GRANULARITY != 0)? DEFAULT_GRANULARITY : psize);
1714 SYSTEM_INFO system_info;
1715 GetSystemInfo(&system_info);
1716 psize = system_info.dwPageSize;
1717 gsize = ((DEFAULT_GRANULARITY != 0)?
1718 DEFAULT_GRANULARITY : system_info.dwAllocationGranularity);
1722 /* Sanity-check configuration:
1723 size_t must be unsigned and as wide as pointer type.
1724 ints must be at least 4 bytes.
1725 alignment must be at least 8.
1726 Alignment, min chunk size, and page size must all be powers of 2.
1728 if ((sizeof(size_t) != sizeof(char*)) ||
1729 (MAX_SIZE_T < MIN_CHUNK_SIZE) ||
1730 (sizeof(int) < 4) ||
1731 (MALLOC_ALIGNMENT < (size_t)8U) ||
1732 ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-SIZE_T_ONE)) != 0) ||
1733 ((MCHUNK_SIZE & (MCHUNK_SIZE-SIZE_T_ONE)) != 0) ||
1734 ((gsize & (gsize-SIZE_T_ONE)) != 0) ||
1735 ((psize & (psize-SIZE_T_ONE)) != 0))
1737 mparams.granularity = gsize;
1738 mparams.page_size = psize;
1739 mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD;
1740 mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD;
1741 #if MORECORE_CONTIGUOUS
1742 mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT;
1743 #else /* MORECORE_CONTIGUOUS */
1744 mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT;
1745 #endif /* MORECORE_CONTIGUOUS */
1748 /* Set up lock for main malloc area */
1749 gm->mflags = mparams.default_mflags;
1750 (void)INITIAL_LOCK(&gm->mutex);
1753 pthread_atfork(&pre_fork, &post_fork_parent, &post_fork_child);
1757 #ifndef DLM_MAGIC_CONSTANT
1760 unsigned char buf[sizeof(size_t)];
1761 /* Try to use /dev/urandom, else fall back on using time */
1762 if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 &&
1763 read(fd, buf, sizeof(buf)) == sizeof(buf)) {
1764 magic = *((size_t *) buf);
1768 #endif /* USE_DEV_RANDOM */
1770 magic = (size_t)(GetTickCount() ^ (size_t)0x55555555U);
1771 #elif defined(LACKS_TIME_H)
1772 magic = (size_t)&magic ^ (size_t)0x55555555U;
1774 magic = (size_t)(time(0) ^ (size_t)0x55555555U);
1776 magic |= (size_t)8U; /* ensure nonzero */
1777 magic &= ~(size_t)7U; /* improve chances of fault for bad values */
1779 magic = DLM_MAGIC_CONSTANT;
1781 /* Until memory modes commonly available, use volatile-write */
1782 (*(volatile size_t *)(&(mparams.magic))) = magic;
1786 RELEASE_MALLOC_GLOBAL_LOCK();
1790 /* support for mallopt */
1791 static int change_mparam(int param_number, int value) {
1793 ensure_initialization();
1794 val = (value == -1)? MAX_SIZE_T : (size_t)value;
1795 switch(param_number) {
1796 case M_TRIM_THRESHOLD:
1797 mparams.trim_threshold = val;
1800 if (val >= mparams.page_size && ((val & (val-1)) == 0)) {
1801 mparams.granularity = val;
1806 case M_MMAP_THRESHOLD:
1807 mparams.mmap_threshold = val;
1815 /* ------------------------- Debugging Support --------------------------- */
1817 /* Check properties of any chunk, whether free, inuse, mmapped etc */
1818 static void do_check_any_chunk(mstate m, mchunkptr p) {
1819 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
1820 assert(ok_address(m, p));
1823 /* Check properties of top chunk */
1824 static void do_check_top_chunk(mstate m, mchunkptr p) {
1825 msegmentptr sp = segment_holding(m, (char*)p);
1826 size_t sz = p->head & ~INUSE_BITS; /* third-lowest bit can be set! */
1828 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
1829 assert(ok_address(m, p));
1830 assert(sz == m->topsize);
1832 assert(sz == ((sp->base + sp->size) - (char*)p) - TOP_FOOT_SIZE);
1834 assert(!pinuse(chunk_plus_offset(p, sz)));
1837 /* Check properties of (inuse) mmapped chunks */
1838 static void do_check_mmapped_chunk(mstate m, mchunkptr p) {
1839 size_t sz = chunksize(p);
1840 size_t len = (sz + (p->prev_foot) + MMAP_FOOT_PAD);
1841 assert(is_mmapped(p));
1842 assert(use_mmap(m));
1843 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
1844 assert(ok_address(m, p));
1845 assert(!is_small(sz));
1846 assert((len & (mparams.page_size-SIZE_T_ONE)) == 0);
1847 assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD);
1848 assert(chunk_plus_offset(p, sz+SIZE_T_SIZE)->head == 0);
1851 /* Check properties of inuse chunks */
1852 static void do_check_inuse_chunk(mstate m, mchunkptr p) {
1853 do_check_any_chunk(m, p);
1854 assert(is_inuse(p));
1855 assert(next_pinuse(p));
1856 /* If not pinuse and not mmapped, previous chunk has OK offset */
1857 assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p);
1859 do_check_mmapped_chunk(m, p);
1862 /* Check properties of free chunks */
1863 static void do_check_free_chunk(mstate m, mchunkptr p) {
1864 size_t sz = chunksize(p);
1865 mchunkptr next = chunk_plus_offset(p, sz);
1866 do_check_any_chunk(m, p);
1867 assert(!is_inuse(p));
1868 assert(!next_pinuse(p));
1869 assert (!is_mmapped(p));
1870 if (p != m->dv && p != m->top) {
1871 if (sz >= MIN_CHUNK_SIZE) {
1872 assert((sz & CHUNK_ALIGN_MASK) == 0);
1873 assert(is_aligned(chunk2mem(p)));
1874 assert(next->prev_foot == sz);
1876 assert (next == m->top || is_inuse(next));
1877 assert(p->fd->bk == p);
1878 assert(p->bk->fd == p);
1880 else /* markers are always of size SIZE_T_SIZE */
1881 assert(sz == SIZE_T_SIZE);
1885 /* Check properties of malloced chunks at the point they are malloced */
1886 static void do_check_malloced_chunk(mstate m, void* mem, size_t s) {
1888 mchunkptr p = mem2chunk(mem);
1889 size_t sz = p->head & ~INUSE_BITS;
1890 do_check_inuse_chunk(m, p);
1891 assert((sz & CHUNK_ALIGN_MASK) == 0);
1892 assert(sz >= MIN_CHUNK_SIZE);
1894 /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */
1895 assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE));
1899 /* Check a tree and its subtrees. */
1900 static void do_check_tree(mstate m, tchunkptr t) {
1903 bindex_t tindex = t->index;
1904 size_t tsize = chunksize(t);
1906 compute_tree_index(tsize, idx);
1907 assert(tindex == idx);
1908 assert(tsize >= MIN_LARGE_SIZE);
1909 assert(tsize >= minsize_for_tree_index(idx));
1910 assert((idx == NTREEBINS-1) || (tsize < minsize_for_tree_index((idx+1))));
1912 do { /* traverse through chain of same-sized nodes */
1913 do_check_any_chunk(m, ((mchunkptr)u));
1914 assert(u->index == tindex);
1915 assert(chunksize(u) == tsize);
1916 assert(!is_inuse(u));
1917 assert(!next_pinuse(u));
1918 assert(u->fd->bk == u);
1919 assert(u->bk->fd == u);
1920 if (u->parent == 0) {
1921 assert(u->child[0] == 0);
1922 assert(u->child[1] == 0);
1925 assert(head == 0); /* only one node on chain has parent */
1927 assert(u->parent != u);
1928 assert (u->parent->child[0] == u ||
1929 u->parent->child[1] == u ||
1930 *((tbinptr*)(u->parent)) == u);
1931 if (u->child[0] != 0) {
1932 assert(u->child[0]->parent == u);
1933 assert(u->child[0] != u);
1934 do_check_tree(m, u->child[0]);
1936 if (u->child[1] != 0) {
1937 assert(u->child[1]->parent == u);
1938 assert(u->child[1] != u);
1939 do_check_tree(m, u->child[1]);
1941 if (u->child[0] != 0 && u->child[1] != 0) {
1942 assert(chunksize(u->child[0]) < chunksize(u->child[1]));
1950 /* Check all the chunks in a treebin. */
1951 static void do_check_treebin(mstate m, bindex_t i) {
1952 tbinptr* tb = treebin_at(m, i);
1954 int empty = (m->treemap & (1U << i)) == 0;
1958 do_check_tree(m, t);
1961 /* Check all the chunks in a smallbin. */
1962 static void do_check_smallbin(mstate m, bindex_t i) {
1963 sbinptr b = smallbin_at(m, i);
1964 mchunkptr p = b->bk;
1965 unsigned int empty = (m->smallmap & (1U << i)) == 0;
1969 for (; p != b; p = p->bk) {
1970 size_t size = chunksize(p);
1972 /* each chunk claims to be free */
1973 do_check_free_chunk(m, p);
1974 /* chunk belongs in bin */
1975 assert(small_index(size) == i);
1976 assert(p->bk == b || chunksize(p->bk) == chunksize(p));
1977 /* chunk is followed by an inuse chunk */
1979 if (q->head != FENCEPOST_HEAD)
1980 do_check_inuse_chunk(m, q);
1985 /* Find x in a bin. Used in other check functions. */
1986 static int bin_find(mstate m, mchunkptr x) {
1987 size_t size = chunksize(x);
1988 if (is_small(size)) {
1989 bindex_t sidx = small_index(size);
1990 sbinptr b = smallbin_at(m, sidx);
1991 if (smallmap_is_marked(m, sidx)) {
1996 } while ((p = p->fd) != b);
2001 compute_tree_index(size, tidx);
2002 if (treemap_is_marked(m, tidx)) {
2003 tchunkptr t = *treebin_at(m, tidx);
2004 size_t sizebits = size << leftshift_for_tree_index(tidx);
2005 while (t != 0 && chunksize(t) != size) {
2006 t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
2012 if (u == (tchunkptr)x)
2014 } while ((u = u->fd) != t);
2021 /* Traverse each chunk and check it; return total */
2022 static size_t traverse_and_check(mstate m) {
2024 if (is_initialized(m)) {
2025 msegmentptr s = &m->seg;
2026 sum += m->topsize + TOP_FOOT_SIZE;
2028 mchunkptr q = align_as_chunk(s->base);
2029 mchunkptr lastq = 0;
2031 while (segment_holds(s, q) &&
2032 q != m->top && q->head != FENCEPOST_HEAD) {
2033 sum += chunksize(q);
2035 assert(!bin_find(m, q));
2036 do_check_inuse_chunk(m, q);
2039 assert(q == m->dv || bin_find(m, q));
2040 assert(lastq == 0 || is_inuse(lastq)); /* Not 2 consecutive free */
2041 do_check_free_chunk(m, q);
2053 /* Check all properties of malloc_state. */
2054 static void do_check_malloc_state(mstate m) {
2058 for (i = 0; i < NSMALLBINS; ++i)
2059 do_check_smallbin(m, i);
2060 for (i = 0; i < NTREEBINS; ++i)
2061 do_check_treebin(m, i);
2063 if (m->dvsize != 0) { /* check dv chunk */
2064 do_check_any_chunk(m, m->dv);
2065 assert(m->dvsize == chunksize(m->dv));
2066 assert(m->dvsize >= MIN_CHUNK_SIZE);
2067 assert(bin_find(m, m->dv) == 0);
2070 if (m->top != 0) { /* check top chunk */
2071 do_check_top_chunk(m, m->top);
2072 /*assert(m->topsize == chunksize(m->top)); redundant */
2073 assert(m->topsize > 0);
2074 assert(bin_find(m, m->top) == 0);
2077 total = traverse_and_check(m);
2078 assert(total <= m->footprint);
2079 assert(m->footprint <= m->max_footprint);
2083 /* ----------------------------- statistics ------------------------------ */
2086 CLIB_NOSANITIZE_ADDR
2087 static struct dlmallinfo internal_mallinfo(mstate m) {
2088 struct dlmallinfo nm = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
2089 ensure_initialization();
2090 if (!PREACTION(m)) {
2091 check_malloc_state(m);
2092 if (is_initialized(m)) {
2093 size_t nfree = SIZE_T_ONE; /* top always free */
2094 size_t mfree = m->topsize + TOP_FOOT_SIZE;
2096 msegmentptr s = &m->seg;
2098 mchunkptr q = align_as_chunk(s->base);
2099 while (segment_holds(s, q) &&
2100 q != m->top && q->head != FENCEPOST_HEAD) {
2101 size_t sz = chunksize(q);
2114 nm.hblkhd = m->footprint - sum;
2115 nm.usmblks = m->max_footprint;
2116 nm.uordblks = m->footprint - mfree;
2117 nm.fordblks = mfree;
2118 nm.keepcost = m->topsize;
2125 #endif /* !NO_MALLINFO */
2127 #if !NO_MALLOC_STATS
2128 static void internal_malloc_stats(mstate m) {
2129 ensure_initialization();
2130 if (!PREACTION(m)) {
2134 check_malloc_state(m);
2135 if (is_initialized(m)) {
2136 msegmentptr s = &m->seg;
2137 maxfp = m->max_footprint;
2139 used = fp - (m->topsize + TOP_FOOT_SIZE);
2142 mchunkptr q = align_as_chunk(s->base);
2143 while (segment_holds(s, q) &&
2144 q != m->top && q->head != FENCEPOST_HEAD) {
2146 used -= chunksize(q);
2152 POSTACTION(m); /* drop lock */
2153 fprintf(stderr, "max system bytes = %10lu\n", (unsigned long)(maxfp));
2154 fprintf(stderr, "system bytes = %10lu\n", (unsigned long)(fp));
2155 fprintf(stderr, "in use bytes = %10lu\n", (unsigned long)(used));
2158 #endif /* NO_MALLOC_STATS */
2160 /* ----------------------- Operations on smallbins ----------------------- */
2163 Various forms of linking and unlinking are defined as macros. Even
2164 the ones for trees, which are very long but have very short typical
2165 paths. This is ugly but reduces reliance on inlining support of
2169 /* Link a free chunk into a smallbin */
2170 #define insert_small_chunk(M, P, S) {\
2171 bindex_t I = small_index(S);\
2172 mchunkptr B = smallbin_at(M, I);\
2174 assert(S >= MIN_CHUNK_SIZE);\
2175 if (!smallmap_is_marked(M, I))\
2176 mark_smallmap(M, I);\
2177 else if (RTCHECK(ok_address(M, B->fd)))\
2180 CORRUPTION_ERROR_ACTION(M);\
2188 /* Unlink a chunk from a smallbin */
2189 #define unlink_small_chunk(M, P, S) {\
2190 mchunkptr F = P->fd;\
2191 mchunkptr B = P->bk;\
2192 bindex_t I = small_index(S);\
2195 assert(chunksize(P) == small_index2size(I));\
2196 if (RTCHECK(F == smallbin_at(M,I) || (ok_address(M, F) && F->bk == P))) { \
2198 clear_smallmap(M, I);\
2200 else if (RTCHECK(B == smallbin_at(M,I) ||\
2201 (ok_address(M, B) && B->fd == P))) {\
2206 CORRUPTION_ERROR_ACTION(M);\
2210 CORRUPTION_ERROR_ACTION(M);\
2214 /* Unlink the first chunk from a smallbin */
2215 #define unlink_first_small_chunk(M, B, P, I) {\
2216 mchunkptr F = P->fd;\
2219 assert(chunksize(P) == small_index2size(I));\
2221 clear_smallmap(M, I);\
2223 else if (RTCHECK(ok_address(M, F) && F->bk == P)) {\
2228 CORRUPTION_ERROR_ACTION(M);\
2232 /* Replace dv node, binning the old one */
2233 /* Used only when dvsize known to be small */
2234 #define replace_dv(M, P, S) {\
2235 size_t DVS = M->dvsize;\
2236 assert(is_small(DVS));\
2238 mchunkptr DV = M->dv;\
2239 insert_small_chunk(M, DV, DVS);\
2245 /* ------------------------- Operations on trees ------------------------- */
2247 /* Insert chunk into tree */
2248 #define insert_large_chunk(M, X, S) {\
2251 compute_tree_index(S, I);\
2252 H = treebin_at(M, I);\
2254 X->child[0] = X->child[1] = 0;\
2255 if (!treemap_is_marked(M, I)) {\
2256 mark_treemap(M, I);\
2258 X->parent = (tchunkptr)H;\
2263 size_t K = S << leftshift_for_tree_index(I);\
2265 if (chunksize(T) != S) {\
2266 tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\
2270 else if (RTCHECK(ok_address(M, C))) {\
2277 CORRUPTION_ERROR_ACTION(M);\
2282 tchunkptr F = T->fd;\
2283 if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\
2291 CORRUPTION_ERROR_ACTION(M);\
2302 1. If x is a chained node, unlink it from its same-sized fd/bk links
2303 and choose its bk node as its replacement.
2304 2. If x was the last node of its size, but not a leaf node, it must
2305 be replaced with a leaf node (not merely one with an open left or
2306 right), to make sure that lefts and rights of descendents
2307 correspond properly to bit masks. We use the rightmost descendent
2308 of x. We could use any other leaf, but this is easy to locate and
2309 tends to counteract removal of leftmosts elsewhere, and so keeps
2310 paths shorter than minimally guaranteed. This doesn't loop much
2311 because on average a node in a tree is near the bottom.
2312 3. If x is the base of a chain (i.e., has parent links) relink
2313 x's parent and children to x's replacement (or null if none).
2316 #define unlink_large_chunk(M, X) {\
2317 tchunkptr XP = X->parent;\
2320 tchunkptr F = X->fd;\
2322 if (RTCHECK(ok_address(M, F) && F->bk == X && R->fd == X)) {\
2327 CORRUPTION_ERROR_ACTION(M);\
2332 if (((R = *(RP = &(X->child[1]))) != 0) ||\
2333 ((R = *(RP = &(X->child[0]))) != 0)) {\
2335 while ((*(CP = &(R->child[1])) != 0) ||\
2336 (*(CP = &(R->child[0])) != 0)) {\
2339 if (RTCHECK(ok_address(M, RP)))\
2342 CORRUPTION_ERROR_ACTION(M);\
2347 tbinptr* H = treebin_at(M, X->index);\
2349 if ((*H = R) == 0) \
2350 clear_treemap(M, X->index);\
2352 else if (RTCHECK(ok_address(M, XP))) {\
2353 if (XP->child[0] == X) \
2359 CORRUPTION_ERROR_ACTION(M);\
2361 if (RTCHECK(ok_address(M, R))) {\
2364 if ((C0 = X->child[0]) != 0) {\
2365 if (RTCHECK(ok_address(M, C0))) {\
2370 CORRUPTION_ERROR_ACTION(M);\
2372 if ((C1 = X->child[1]) != 0) {\
2373 if (RTCHECK(ok_address(M, C1))) {\
2378 CORRUPTION_ERROR_ACTION(M);\
2382 CORRUPTION_ERROR_ACTION(M);\
2387 /* Relays to large vs small bin operations */
2389 #define insert_chunk(M, P, S)\
2390 if (is_small(S)) insert_small_chunk(M, P, S)\
2391 else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); }
2393 #define unlink_chunk(M, P, S)\
2394 if (is_small(S)) unlink_small_chunk(M, P, S)\
2395 else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); }
2398 /* Relays to internal calls to malloc/free from realloc, memalign etc */
2401 #define internal_malloc(m, b) mspace_malloc(m, b)
2402 #define internal_free(m, mem) mspace_free(m,mem);
2403 #else /* ONLY_MSPACES */
2405 #define internal_malloc(m, b)\
2406 ((m == gm)? dlmalloc(b) : mspace_malloc(m, b))
2407 #define internal_free(m, mem)\
2408 if (m == gm) dlfree(mem); else mspace_free(m,mem);
2410 #define internal_malloc(m, b) dlmalloc(b)
2411 #define internal_free(m, mem) dlfree(mem)
2412 #endif /* MSPACES */
2413 #endif /* ONLY_MSPACES */
2415 /* ----------------------- Direct-mmapping chunks ----------------------- */
2418 Directly mmapped chunks are set up with an offset to the start of
2419 the mmapped region stored in the prev_foot field of the chunk. This
2420 allows reconstruction of the required argument to MUNMAP when freed,
2421 and also allows adjustment of the returned chunk to meet alignment
2422 requirements (especially in memalign).
2425 /* Malloc using mmap */
2426 static void* mmap_alloc(mstate m, size_t nb) {
2427 size_t mmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
2428 if (m->footprint_limit != 0) {
2429 size_t fp = m->footprint + mmsize;
2430 if (fp <= m->footprint || fp > m->footprint_limit)
2433 if (mmsize > nb) { /* Check for wrap around 0 */
2434 char* mm = (char*)(CALL_DIRECT_MMAP(mmsize));
2436 size_t offset = align_offset(chunk2mem(mm));
2437 size_t psize = mmsize - offset - MMAP_FOOT_PAD;
2438 mchunkptr p = (mchunkptr)(mm + offset);
2439 p->prev_foot = offset;
2441 mark_inuse_foot(m, p, psize);
2442 chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
2443 chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0;
2445 if (m->least_addr == 0 || mm < m->least_addr)
2447 if ((m->footprint += mmsize) > m->max_footprint)
2448 m->max_footprint = m->footprint;
2449 assert(is_aligned(chunk2mem(p)));
2450 check_mmapped_chunk(m, p);
2451 return chunk2mem(p);
2457 /* Realloc using mmap */
2458 static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb, int flags) {
2459 size_t oldsize = chunksize(oldp);
2460 (void)flags; /* placate people compiling -Wunused */
2461 if (is_small(nb)) /* Can't shrink mmap regions below small size */
2463 /* Keep old chunk if big enough but not too big */
2464 if (oldsize >= nb + SIZE_T_SIZE &&
2465 (oldsize - nb) <= (mparams.granularity << 1))
2468 size_t offset = oldp->prev_foot;
2469 size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
2470 size_t newmmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
2471 char* cp = (char*)CALL_MREMAP((char*)oldp - offset,
2472 oldmmsize, newmmsize, flags);
2474 mchunkptr newp = (mchunkptr)(cp + offset);
2475 size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
2477 mark_inuse_foot(m, newp, psize);
2478 chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
2479 chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0;
2481 if (cp < m->least_addr)
2483 if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
2484 m->max_footprint = m->footprint;
2485 check_mmapped_chunk(m, newp);
2493 /* -------------------------- mspace management -------------------------- */
2495 /* Initialize top chunk and its size */
2496 static void init_top(mstate m, mchunkptr p, size_t psize) {
2497 /* Ensure alignment */
2498 size_t offset = align_offset(chunk2mem(p));
2499 p = (mchunkptr)((char*)p + offset);
2504 p->head = psize | PINUSE_BIT;
2505 /* set size of fake trailing chunk holding overhead space only once */
2506 chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE;
2507 m->trim_check = mparams.trim_threshold; /* reset on each update */
2510 /* Initialize bins for a new mstate that is otherwise zeroed out */
2511 static void init_bins(mstate m) {
2512 /* Establish circular links for smallbins */
2514 for (i = 0; i < NSMALLBINS; ++i) {
2515 sbinptr bin = smallbin_at(m,i);
2516 bin->fd = bin->bk = bin;
2520 #if PROCEED_ON_ERROR
2522 /* default corruption action */
2523 static void reset_on_error(mstate m) {
2525 ++malloc_corruption_error_count;
2526 /* Reinitialize fields to forget about all memory */
2527 m->smallmap = m->treemap = 0;
2528 m->dvsize = m->topsize = 0;
2533 for (i = 0; i < NTREEBINS; ++i)
2534 *treebin_at(m, i) = 0;
2537 #endif /* PROCEED_ON_ERROR */
2539 /* Allocate chunk and prepend remainder with chunk in successor base. */
2540 static void* prepend_alloc(mstate m, char* newbase, char* oldbase,
2542 mchunkptr p = align_as_chunk(newbase);
2543 mchunkptr oldfirst = align_as_chunk(oldbase);
2544 size_t psize = (char*)oldfirst - (char*)p;
2545 mchunkptr q = chunk_plus_offset(p, nb);
2546 size_t qsize = psize - nb;
2547 set_size_and_pinuse_of_inuse_chunk(m, p, nb);
2549 assert((char*)oldfirst > (char*)q);
2550 assert(pinuse(oldfirst));
2551 assert(qsize >= MIN_CHUNK_SIZE);
2553 /* consolidate remainder with first chunk of old base */
2554 if (oldfirst == m->top) {
2555 size_t tsize = m->topsize += qsize;
2557 q->head = tsize | PINUSE_BIT;
2558 check_top_chunk(m, q);
2560 else if (oldfirst == m->dv) {
2561 size_t dsize = m->dvsize += qsize;
2563 set_size_and_pinuse_of_free_chunk(q, dsize);
2566 if (!is_inuse(oldfirst)) {
2567 size_t nsize = chunksize(oldfirst);
2568 unlink_chunk(m, oldfirst, nsize);
2569 oldfirst = chunk_plus_offset(oldfirst, nsize);
2572 set_free_with_pinuse(q, qsize, oldfirst);
2573 insert_chunk(m, q, qsize);
2574 check_free_chunk(m, q);
2577 check_malloced_chunk(m, chunk2mem(p), nb);
2578 return chunk2mem(p);
2581 /* Add a segment to hold a new noncontiguous region */
2582 static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) {
2583 /* Determine locations and sizes of segment, fenceposts, old top */
2584 char* old_top = (char*)m->top;
2585 msegmentptr oldsp = segment_holding(m, old_top);
2586 char* old_end = oldsp->base + oldsp->size;
2587 size_t ssize = pad_request(sizeof(struct malloc_segment));
2588 char* rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
2589 size_t offset = align_offset(chunk2mem(rawsp));
2590 char* asp = rawsp + offset;
2591 char* csp = (asp < (old_top + MIN_CHUNK_SIZE))? old_top : asp;
2592 mchunkptr sp = (mchunkptr)csp;
2593 msegmentptr ss = (msegmentptr)(chunk2mem(sp));
2594 mchunkptr tnext = chunk_plus_offset(sp, ssize);
2595 mchunkptr p = tnext;
2598 /* reset top to new space */
2599 init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
2601 /* Set up segment record */
2602 assert(is_aligned(ss));
2603 set_size_and_pinuse_of_inuse_chunk(m, sp, ssize);
2604 *ss = m->seg; /* Push current record */
2605 m->seg.base = tbase;
2606 m->seg.size = tsize;
2607 m->seg.sflags = mmapped;
2610 /* Insert trailing fenceposts */
2612 mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE);
2613 p->head = FENCEPOST_HEAD;
2615 if ((char*)(&(nextp->head)) < old_end)
2620 assert(nfences >= 2);
2622 /* Insert the rest of old top into a bin as an ordinary free chunk */
2623 if (csp != old_top) {
2624 mchunkptr q = (mchunkptr)old_top;
2625 size_t psize = csp - old_top;
2626 mchunkptr tn = chunk_plus_offset(q, psize);
2627 set_free_with_pinuse(q, psize, tn);
2628 insert_chunk(m, q, psize);
2631 check_top_chunk(m, m->top);
2634 /* -------------------------- System allocation -------------------------- */
2636 /* Get memory from system using MORECORE or MMAP */
2637 static void* sys_alloc(mstate m, size_t nb) {
2638 char* tbase = CMFAIL;
2640 flag_t mmap_flag = 0;
2641 size_t asize; /* allocation size */
2643 ensure_initialization();
2645 if (use_noexpand(m))
2648 /* Directly map large chunks, but only if already initialized */
2649 if (use_mmap(m) && nb >= mparams.mmap_threshold && m->topsize != 0) {
2650 void* mem = mmap_alloc(m, nb);
2655 asize = granularity_align(nb + SYS_ALLOC_PADDING);
2657 return 0; /* wraparound */
2658 if (m->footprint_limit != 0) {
2659 size_t fp = m->footprint + asize;
2660 if (fp <= m->footprint || fp > m->footprint_limit)
2665 Try getting memory in any of three ways (in most-preferred to
2666 least-preferred order):
2667 1. A call to MORECORE that can normally contiguously extend memory.
2668 (disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or
2669 or main space is mmapped or a previous contiguous call failed)
2670 2. A call to MMAP new space (disabled if not HAVE_MMAP).
2671 Note that under the default settings, if MORECORE is unable to
2672 fulfill a request, and HAVE_MMAP is true, then mmap is
2673 used as a noncontiguous system allocator. This is a useful backup
2674 strategy for systems with holes in address spaces -- in this case
2675 sbrk cannot contiguously expand the heap, but mmap may be able to
2677 3. A call to MORECORE that cannot usually contiguously extend memory.
2678 (disabled if not HAVE_MORECORE)
2680 In all cases, we need to request enough bytes from system to ensure
2681 we can malloc nb bytes upon success, so pad with enough space for
2682 top_foot, plus alignment-pad to make sure we don't lose bytes if
2683 not on boundary, and round this up to a granularity unit.
2686 if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) {
2688 size_t ssize = asize; /* sbrk call size */
2689 msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top);
2690 ACQUIRE_MALLOC_GLOBAL_LOCK();
2692 if (ss == 0) { /* First time through or recovery */
2693 char* base = (char*)CALL_MORECORE(0);
2694 if (base != CMFAIL) {
2696 /* Adjust to end on a page boundary */
2697 if (!is_page_aligned(base))
2698 ssize += (page_align((size_t)base) - (size_t)base);
2699 fp = m->footprint + ssize; /* recheck limits */
2700 if (ssize > nb && ssize < HALF_MAX_SIZE_T &&
2701 (m->footprint_limit == 0 ||
2702 (fp > m->footprint && fp <= m->footprint_limit)) &&
2703 (br = (char*)(CALL_MORECORE(ssize))) == base) {
2710 /* Subtract out existing available top space from MORECORE request. */
2711 ssize = granularity_align(nb - m->topsize + SYS_ALLOC_PADDING);
2712 /* Use mem here only if it did continuously extend old space */
2713 if (ssize < HALF_MAX_SIZE_T &&
2714 (br = (char*)(CALL_MORECORE(ssize))) == ss->base+ss->size) {
2720 if (tbase == CMFAIL) { /* Cope with partial failure */
2721 if (br != CMFAIL) { /* Try to use/extend the space we did get */
2722 if (ssize < HALF_MAX_SIZE_T &&
2723 ssize < nb + SYS_ALLOC_PADDING) {
2724 size_t esize = granularity_align(nb + SYS_ALLOC_PADDING - ssize);
2725 if (esize < HALF_MAX_SIZE_T) {
2726 char* end = (char*)CALL_MORECORE(esize);
2729 else { /* Can't use; try to release */
2730 (void) CALL_MORECORE(-ssize);
2736 if (br != CMFAIL) { /* Use the space we did get */
2741 disable_contiguous(m); /* Don't try contiguous path in the future */
2744 RELEASE_MALLOC_GLOBAL_LOCK();
2747 if (HAVE_MMAP && tbase == CMFAIL) { /* Try MMAP */
2748 char* mp = (char*)(CALL_MMAP(asize));
2752 mmap_flag = USE_MMAP_BIT;
2756 if (HAVE_MORECORE && tbase == CMFAIL) { /* Try noncontiguous MORECORE */
2757 if (asize < HALF_MAX_SIZE_T) {
2760 ACQUIRE_MALLOC_GLOBAL_LOCK();
2761 br = (char*)(CALL_MORECORE(asize));
2762 end = (char*)(CALL_MORECORE(0));
2763 RELEASE_MALLOC_GLOBAL_LOCK();
2764 if (br != CMFAIL && end != CMFAIL && br < end) {
2765 size_t ssize = end - br;
2766 if (ssize > nb + TOP_FOOT_SIZE) {
2774 if (tbase != CMFAIL) {
2776 if ((m->footprint += tsize) > m->max_footprint)
2777 m->max_footprint = m->footprint;
2779 if (!is_initialized(m)) { /* first-time initialization */
2780 if (m->least_addr == 0 || tbase < m->least_addr)
2781 m->least_addr = tbase;
2782 m->seg.base = tbase;
2783 m->seg.size = tsize;
2784 m->seg.sflags = mmap_flag;
2785 m->magic = mparams.magic;
2786 m->release_checks = MAX_RELEASE_CHECK_RATE;
2790 init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
2794 /* Offset top by embedded malloc_state */
2795 mchunkptr mn = next_chunk(mem2chunk(m));
2796 init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) -TOP_FOOT_SIZE);
2801 /* Try to merge with an existing segment */
2802 msegmentptr sp = &m->seg;
2803 /* Only consider most recent segment if traversal suppressed */
2804 while (sp != 0 && tbase != sp->base + sp->size)
2805 sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next;
2807 !is_extern_segment(sp) &&
2808 (sp->sflags & USE_MMAP_BIT) == mmap_flag &&
2809 segment_holds(sp, m->top)) { /* append */
2811 init_top(m, m->top, m->topsize + tsize);
2814 if (tbase < m->least_addr)
2815 m->least_addr = tbase;
2817 while (sp != 0 && sp->base != tbase + tsize)
2818 sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next;
2820 !is_extern_segment(sp) &&
2821 (sp->sflags & USE_MMAP_BIT) == mmap_flag) {
2822 char* oldbase = sp->base;
2825 return prepend_alloc(m, tbase, oldbase, nb);
2828 add_segment(m, tbase, tsize, mmap_flag);
2832 if (nb < m->topsize) { /* Allocate from new or extended top space */
2833 size_t rsize = m->topsize -= nb;
2834 mchunkptr p = m->top;
2835 mchunkptr r = m->top = chunk_plus_offset(p, nb);
2836 r->head = rsize | PINUSE_BIT;
2837 set_size_and_pinuse_of_inuse_chunk(m, p, nb);
2838 check_top_chunk(m, m->top);
2839 check_malloced_chunk(m, chunk2mem(p), nb);
2840 return chunk2mem(p);
2844 MALLOC_FAILURE_ACTION;
2848 /* ----------------------- system deallocation -------------------------- */
2850 /* Unmap and unlink any mmapped segments that don't contain used chunks */
2851 CLIB_NOSANITIZE_ADDR
2852 static size_t release_unused_segments(mstate m) {
2853 size_t released = 0;
2855 msegmentptr pred = &m->seg;
2856 msegmentptr sp = pred->next;
2858 char* base = sp->base;
2859 size_t size = sp->size;
2860 msegmentptr next = sp->next;
2862 if (is_mmapped_segment(sp) && !is_extern_segment(sp)) {
2863 mchunkptr p = align_as_chunk(base);
2864 size_t psize = chunksize(p);
2865 /* Can unmap if first chunk holds entire segment and not pinned */
2866 if (!is_inuse(p) && (char*)p + psize >= base + size - TOP_FOOT_SIZE) {
2867 tchunkptr tp = (tchunkptr)p;
2868 assert(segment_holds(sp, (char*)sp));
2874 unlink_large_chunk(m, tp);
2876 if (CALL_MUNMAP(base, size) == 0) {
2878 m->footprint -= size;
2879 /* unlink obsoleted record */
2883 else { /* back out if cannot unmap */
2884 insert_large_chunk(m, tp, psize);
2888 if (NO_SEGMENT_TRAVERSAL) /* scan only first segment */
2893 /* Reset check counter */
2894 m->release_checks = (((size_t) nsegs > (size_t) MAX_RELEASE_CHECK_RATE)?
2895 (size_t) nsegs : (size_t) MAX_RELEASE_CHECK_RATE);
2899 CLIB_NOSANITIZE_ADDR
2900 static int sys_trim(mstate m, size_t pad) {
2901 size_t released = 0;
2902 ensure_initialization();
2903 if (pad < MAX_REQUEST && is_initialized(m)) {
2904 pad += TOP_FOOT_SIZE; /* ensure enough room for segment overhead */
2906 if (m->topsize > pad) {
2907 /* Shrink top space in granularity-size units, keeping at least one */
2908 size_t unit = mparams.granularity;
2909 size_t extra = ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit -
2911 msegmentptr sp = segment_holding(m, (char*)m->top);
2913 if (!is_extern_segment(sp)) {
2914 if (is_mmapped_segment(sp)) {
2916 sp->size >= extra &&
2917 !has_segment_link(m, sp)) { /* can't shrink if pinned */
2918 size_t newsize = sp->size - extra;
2919 (void)newsize; /* placate people compiling -Wunused-variable */
2920 /* Prefer mremap, fall back to munmap */
2921 if ((CALL_MREMAP(sp->base, sp->size, newsize, 0) != MFAIL) ||
2922 (CALL_MUNMAP(sp->base + newsize, extra) == 0)) {
2927 else if (HAVE_MORECORE) {
2928 if (extra >= HALF_MAX_SIZE_T) /* Avoid wrapping negative */
2929 extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit;
2930 ACQUIRE_MALLOC_GLOBAL_LOCK();
2932 /* Make sure end of memory is where we last set it. */
2933 char* old_br = (char*)(CALL_MORECORE(0));
2934 if (old_br == sp->base + sp->size) {
2935 char* rel_br = (char*)(CALL_MORECORE(-extra));
2936 char* new_br = (char*)(CALL_MORECORE(0));
2937 if (rel_br != CMFAIL && new_br < old_br)
2938 released = old_br - new_br;
2941 RELEASE_MALLOC_GLOBAL_LOCK();
2945 if (released != 0) {
2946 sp->size -= released;
2947 m->footprint -= released;
2948 init_top(m, m->top, m->topsize - released);
2949 check_top_chunk(m, m->top);
2953 /* Unmap any unused mmapped segments */
2955 released += release_unused_segments(m);
2957 /* On failure, disable autotrim to avoid repeated failed future calls */
2958 if (released == 0 && m->topsize > m->trim_check)
2959 m->trim_check = MAX_SIZE_T;
2962 return (released != 0)? 1 : 0;
2965 /* Consolidate and bin a chunk. Differs from exported versions
2966 of free mainly in that the chunk need not be marked as inuse.
2968 CLIB_NOSANITIZE_ADDR
2969 static void dispose_chunk(mstate m, mchunkptr p, size_t psize) {
2970 mchunkptr next = chunk_plus_offset(p, psize);
2973 size_t prevsize = p->prev_foot;
2974 if (is_mmapped(p)) {
2975 psize += prevsize + MMAP_FOOT_PAD;
2976 if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
2977 m->footprint -= psize;
2980 prev = chunk_minus_offset(p, prevsize);
2983 if (RTCHECK(ok_address(m, prev))) { /* consolidate backward */
2985 unlink_chunk(m, p, prevsize);
2987 else if ((next->head & INUSE_BITS) == INUSE_BITS) {
2989 set_free_with_pinuse(p, psize, next);
2994 CORRUPTION_ERROR_ACTION(m);
2998 if (RTCHECK(ok_address(m, next))) {
2999 if (!cinuse(next)) { /* consolidate forward */
3000 if (next == m->top) {
3001 size_t tsize = m->topsize += psize;
3003 p->head = tsize | PINUSE_BIT;
3010 else if (next == m->dv) {
3011 size_t dsize = m->dvsize += psize;
3013 set_size_and_pinuse_of_free_chunk(p, dsize);
3017 size_t nsize = chunksize(next);
3019 unlink_chunk(m, next, nsize);
3020 set_size_and_pinuse_of_free_chunk(p, psize);
3028 set_free_with_pinuse(p, psize, next);
3030 insert_chunk(m, p, psize);
3033 CORRUPTION_ERROR_ACTION(m);
3037 /* ---------------------------- malloc --------------------------- */
3039 /* allocate a large request from the best fitting chunk in a treebin */
3040 CLIB_NOSANITIZE_ADDR
3041 static void* tmalloc_large(mstate m, size_t nb) {
3043 size_t rsize = -nb; /* Unsigned negation */
3046 compute_tree_index(nb, idx);
3047 if ((t = *treebin_at(m, idx)) != 0) {
3048 /* Traverse tree for this bin looking for node with size == nb */
3049 size_t sizebits = nb << leftshift_for_tree_index(idx);
3050 tchunkptr rst = 0; /* The deepest untaken right subtree */
3053 size_t trem = chunksize(t) - nb;
3056 if ((rsize = trem) == 0)
3060 t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
3061 if (rt != 0 && rt != t)
3064 t = rst; /* set t to least subtree holding sizes > nb */
3070 if (t == 0 && v == 0) { /* set t to root of next non-empty treebin */
3071 binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap;
3072 if (leftbits != 0) {
3074 binmap_t leastbit = least_bit(leftbits);
3075 compute_bit2idx(leastbit, i);
3076 t = *treebin_at(m, i);
3080 while (t != 0) { /* find smallest of tree or subtree */
3081 size_t trem = chunksize(t) - nb;
3086 t = leftmost_child(t);
3089 /* If dv is a better fit, return 0 so malloc will use it */
3090 if (v != 0 && rsize < (size_t)(m->dvsize - nb)) {
3091 if (RTCHECK(ok_address(m, v))) { /* split */
3092 mchunkptr r = chunk_plus_offset(v, nb);
3093 assert(chunksize(v) == rsize + nb);
3094 if (RTCHECK(ok_next(v, r))) {
3095 unlink_large_chunk(m, v);
3096 if (rsize < MIN_CHUNK_SIZE)
3097 set_inuse_and_pinuse(m, v, (rsize + nb));
3099 set_size_and_pinuse_of_inuse_chunk(m, v, nb);
3100 set_size_and_pinuse_of_free_chunk(r, rsize);
3101 insert_chunk(m, r, rsize);
3103 return chunk2mem(v);
3106 CORRUPTION_ERROR_ACTION(m);
3111 /* allocate a small request from the best fitting chunk in a treebin */
3112 CLIB_NOSANITIZE_ADDR
3113 static void* tmalloc_small(mstate m, size_t nb) {
3117 binmap_t leastbit = least_bit(m->treemap);
3118 compute_bit2idx(leastbit, i);
3119 v = t = *treebin_at(m, i);
3120 rsize = chunksize(t) - nb;
3122 while ((t = leftmost_child(t)) != 0) {
3123 size_t trem = chunksize(t) - nb;
3130 if (RTCHECK(ok_address(m, v))) {
3131 mchunkptr r = chunk_plus_offset(v, nb);
3132 assert(chunksize(v) == rsize + nb);
3133 if (RTCHECK(ok_next(v, r))) {
3134 unlink_large_chunk(m, v);
3135 if (rsize < MIN_CHUNK_SIZE)
3136 set_inuse_and_pinuse(m, v, (rsize + nb));
3138 set_size_and_pinuse_of_inuse_chunk(m, v, nb);
3139 set_size_and_pinuse_of_free_chunk(r, rsize);
3140 replace_dv(m, r, rsize);
3142 return chunk2mem(v);
3146 CORRUPTION_ERROR_ACTION(m);
3152 void* dlmalloc(size_t bytes) {
3155 If a small request (< 256 bytes minus per-chunk overhead):
3156 1. If one exists, use a remainderless chunk in associated smallbin.
3157 (Remainderless means that there are too few excess bytes to
3158 represent as a chunk.)
3159 2. If it is big enough, use the dv chunk, which is normally the
3160 chunk adjacent to the one used for the most recent small request.
3161 3. If one exists, split the smallest available chunk in a bin,
3162 saving remainder in dv.
3163 4. If it is big enough, use the top chunk.
3164 5. If available, get memory from system and use it
3165 Otherwise, for a large request:
3166 1. Find the smallest available binned chunk that fits, and use it
3167 if it is better fitting than dv chunk, splitting if necessary.
3168 2. If better fitting than any binned chunk, use the dv chunk.
3169 3. If it is big enough, use the top chunk.
3170 4. If request size >= mmap threshold, try to directly mmap this chunk.
3171 5. If available, get memory from system and use it
3173 The ugly goto's here ensure that postaction occurs along all paths.
3177 ensure_initialization(); /* initialize in sys_alloc if not using locks */
3180 if (!PREACTION(gm)) {
3183 if (bytes <= MAX_SMALL_REQUEST) {
3186 nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
3187 idx = small_index(nb);
3188 smallbits = gm->smallmap >> idx;
3190 if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
3192 idx += ~smallbits & 1; /* Uses next bin if idx empty */
3193 b = smallbin_at(gm, idx);
3195 assert(chunksize(p) == small_index2size(idx));
3196 unlink_first_small_chunk(gm, b, p, idx);
3197 set_inuse_and_pinuse(gm, p, small_index2size(idx));
3199 check_malloced_chunk(gm, mem, nb);
3203 else if (nb > gm->dvsize) {
3204 if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
3208 binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
3209 binmap_t leastbit = least_bit(leftbits);
3210 compute_bit2idx(leastbit, i);
3211 b = smallbin_at(gm, i);
3213 assert(chunksize(p) == small_index2size(i));
3214 unlink_first_small_chunk(gm, b, p, i);
3215 rsize = small_index2size(i) - nb;
3216 /* Fit here cannot be remainderless if 4byte sizes */
3217 if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
3218 set_inuse_and_pinuse(gm, p, small_index2size(i));
3220 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
3221 r = chunk_plus_offset(p, nb);
3222 set_size_and_pinuse_of_free_chunk(r, rsize);
3223 replace_dv(gm, r, rsize);
3226 check_malloced_chunk(gm, mem, nb);
3230 else if (gm->treemap != 0 && (mem = tmalloc_small(gm, nb)) != 0) {
3231 check_malloced_chunk(gm, mem, nb);
3236 else if (bytes >= MAX_REQUEST)
3237 nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
3239 nb = pad_request(bytes);
3240 if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) {
3241 check_malloced_chunk(gm, mem, nb);
3246 if (nb <= gm->dvsize) {
3247 size_t rsize = gm->dvsize - nb;
3248 mchunkptr p = gm->dv;
3249 if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
3250 mchunkptr r = gm->dv = chunk_plus_offset(p, nb);
3252 set_size_and_pinuse_of_free_chunk(r, rsize);
3253 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
3255 else { /* exhaust dv */
3256 size_t dvs = gm->dvsize;
3259 set_inuse_and_pinuse(gm, p, dvs);
3262 check_malloced_chunk(gm, mem, nb);
3266 else if (nb < gm->topsize) { /* Split top */
3267 size_t rsize = gm->topsize -= nb;
3268 mchunkptr p = gm->top;
3269 mchunkptr r = gm->top = chunk_plus_offset(p, nb);
3270 r->head = rsize | PINUSE_BIT;
3271 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
3273 check_top_chunk(gm, gm->top);
3274 check_malloced_chunk(gm, mem, nb);
3278 mem = sys_alloc(gm, nb);
3288 /* ---------------------------- free --------------------------- */
3290 void dlfree(void* mem) {
3292 Consolidate freed chunks with preceding or succeeding bordering
3293 free chunks, if they exist, and then place in a bin. Intermixed
3294 with special cases for top, dv, mmapped chunks, and usage errors.
3298 mchunkptr p = mem2chunk(mem);
3300 mstate fm = get_mstate_for(p);
3301 if (!ok_magic(fm)) {
3302 USAGE_ERROR_ACTION(fm, p);
3307 #endif /* FOOTERS */
3308 if (!PREACTION(fm)) {
3309 check_inuse_chunk(fm, p);
3310 if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
3311 size_t psize = chunksize(p);
3312 mchunkptr next = chunk_plus_offset(p, psize);
3314 size_t prevsize = p->prev_foot;
3315 if (is_mmapped(p)) {
3316 psize += prevsize + MMAP_FOOT_PAD;
3317 if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
3318 fm->footprint -= psize;
3322 mchunkptr prev = chunk_minus_offset(p, prevsize);
3325 if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
3327 unlink_chunk(fm, p, prevsize);
3329 else if ((next->head & INUSE_BITS) == INUSE_BITS) {
3331 set_free_with_pinuse(p, psize, next);
3340 if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
3341 if (!cinuse(next)) { /* consolidate forward */
3342 if (next == fm->top) {
3343 size_t tsize = fm->topsize += psize;
3345 p->head = tsize | PINUSE_BIT;
3350 if (should_trim(fm, tsize))
3354 else if (next == fm->dv) {
3355 size_t dsize = fm->dvsize += psize;
3357 set_size_and_pinuse_of_free_chunk(p, dsize);
3361 size_t nsize = chunksize(next);
3363 unlink_chunk(fm, next, nsize);
3364 set_size_and_pinuse_of_free_chunk(p, psize);
3372 set_free_with_pinuse(p, psize, next);
3374 if (is_small(psize)) {
3375 insert_small_chunk(fm, p, psize);
3376 check_free_chunk(fm, p);
3379 tchunkptr tp = (tchunkptr)p;
3380 insert_large_chunk(fm, tp, psize);
3381 check_free_chunk(fm, p);
3382 if (--fm->release_checks == 0)
3383 release_unused_segments(fm);
3389 USAGE_ERROR_ACTION(fm, p);
3396 #endif /* FOOTERS */
3399 void* dlcalloc(size_t n_elements, size_t elem_size) {
3402 if (n_elements != 0) {
3403 req = n_elements * elem_size;
3404 if (((n_elements | elem_size) & ~(size_t)0xffff) &&
3405 (req / n_elements != elem_size))
3406 req = MAX_SIZE_T; /* force downstream failure on overflow */
3408 mem = dlmalloc(req);
3409 if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
3410 memset(mem, 0, req);
3414 #endif /* !ONLY_MSPACES */
3416 /* ------------ Internal support for realloc, memalign, etc -------------- */
3418 /* Try to realloc; only in-place unless can_move true */
3419 static mchunkptr try_realloc_chunk(mstate m, mchunkptr p, size_t nb,
3422 size_t oldsize = chunksize(p);
3423 mchunkptr next = chunk_plus_offset(p, oldsize);
3424 if (RTCHECK(ok_address(m, p) && ok_inuse(p) &&
3425 ok_next(p, next) && ok_pinuse(next))) {
3426 if (is_mmapped(p)) {
3427 newp = mmap_resize(m, p, nb, can_move);
3429 else if (oldsize >= nb) { /* already big enough */
3430 size_t rsize = oldsize - nb;
3431 if (rsize >= MIN_CHUNK_SIZE) { /* split off remainder */
3432 mchunkptr r = chunk_plus_offset(p, nb);
3433 set_inuse(m, p, nb);
3434 set_inuse(m, r, rsize);
3435 dispose_chunk(m, r, rsize);
3439 else if (next == m->top) { /* extend into top */
3440 if (oldsize + m->topsize > nb) {
3441 size_t newsize = oldsize + m->topsize;
3442 size_t newtopsize = newsize - nb;
3443 mchunkptr newtop = chunk_plus_offset(p, nb);
3444 set_inuse(m, p, nb);
3445 newtop->head = newtopsize |PINUSE_BIT;
3447 m->topsize = newtopsize;
3451 else if (next == m->dv) { /* extend into dv */
3452 size_t dvs = m->dvsize;
3453 if (oldsize + dvs >= nb) {
3454 size_t dsize = oldsize + dvs - nb;
3455 if (dsize >= MIN_CHUNK_SIZE) {
3456 mchunkptr r = chunk_plus_offset(p, nb);
3457 mchunkptr n = chunk_plus_offset(r, dsize);
3458 set_inuse(m, p, nb);
3459 set_size_and_pinuse_of_free_chunk(r, dsize);
3464 else { /* exhaust dv */
3465 size_t newsize = oldsize + dvs;
3466 set_inuse(m, p, newsize);
3473 else if (!cinuse(next)) { /* extend into next free chunk */
3474 size_t nextsize = chunksize(next);
3475 if (oldsize + nextsize >= nb) {
3476 size_t rsize = oldsize + nextsize - nb;
3477 unlink_chunk(m, next, nextsize);
3478 if (rsize < MIN_CHUNK_SIZE) {
3479 size_t newsize = oldsize + nextsize;
3480 set_inuse(m, p, newsize);
3483 mchunkptr r = chunk_plus_offset(p, nb);
3484 set_inuse(m, p, nb);
3485 set_inuse(m, r, rsize);
3486 dispose_chunk(m, r, rsize);
3493 USAGE_ERROR_ACTION(m, chunk2mem(p));
3498 CLIB_NOSANITIZE_ADDR
3499 static void* internal_memalign(mstate m, size_t alignment, size_t bytes) {
3501 if (alignment < MIN_CHUNK_SIZE) /* must be at least a minimum chunk size */
3502 alignment = MIN_CHUNK_SIZE;
3503 if ((alignment & (alignment-SIZE_T_ONE)) != 0) {/* Ensure a power of 2 */
3504 size_t a = MALLOC_ALIGNMENT << 1;
3505 while (a < alignment) a <<= 1;
3508 if (bytes >= MAX_REQUEST - alignment) {
3509 if (m != 0) { /* Test isn't needed but avoids compiler warning */
3510 MALLOC_FAILURE_ACTION;
3514 size_t nb = request2size(bytes);
3515 size_t req = nb + alignment + MIN_CHUNK_SIZE - CHUNK_OVERHEAD;
3516 mem = internal_malloc(m, req);
3518 mchunkptr p = mem2chunk(mem);
3521 if ((((size_t)(mem)) & (alignment - 1)) != 0) { /* misaligned */
3523 Find an aligned spot inside chunk. Since we need to give
3524 back leading space in a chunk of at least MIN_CHUNK_SIZE, if
3525 the first calculation places us at a spot with less than
3526 MIN_CHUNK_SIZE leader, we can move to the next aligned spot.
3527 We've allocated enough total room so that this is always
3530 char* br = (char*)mem2chunk((size_t)(((size_t)((char*)mem + alignment -
3533 char* pos = ((size_t)(br - (char*)(p)) >= MIN_CHUNK_SIZE)?
3535 mchunkptr newp = (mchunkptr)pos;
3536 size_t leadsize = pos - (char*)(p);
3537 size_t newsize = chunksize(p) - leadsize;
3539 if (is_mmapped(p)) { /* For mmapped chunks, just adjust offset */
3540 newp->prev_foot = p->prev_foot + leadsize;
3541 newp->head = newsize;
3543 else { /* Otherwise, give back leader, use the rest */
3544 set_inuse(m, newp, newsize);
3545 set_inuse(m, p, leadsize);
3546 dispose_chunk(m, p, leadsize);
3551 /* Give back spare room at the end */
3552 if (!is_mmapped(p)) {
3553 size_t size = chunksize(p);
3554 if (size > nb + MIN_CHUNK_SIZE) {
3555 size_t remainder_size = size - nb;
3556 mchunkptr remainder = chunk_plus_offset(p, nb);
3557 set_inuse(m, p, nb);
3558 set_inuse(m, remainder, remainder_size);
3559 dispose_chunk(m, remainder, remainder_size);
3564 assert (chunksize(p) >= nb);
3565 assert(((size_t)mem & (alignment - 1)) == 0);
3566 check_inuse_chunk(m, p);
3574 Common support for independent_X routines, handling
3575 all of the combinations that can result.
3577 bit 0 set if all elements are same size (using sizes[0])
3578 bit 1 set if elements should be zeroed
3580 static void** ialloc(mstate m,
3586 size_t element_size; /* chunksize of each element, if all same */
3587 size_t contents_size; /* total size of elements */
3588 size_t array_size; /* request size of pointer array */
3589 void* mem; /* malloced aggregate space */
3590 mchunkptr p; /* corresponding chunk */
3591 size_t remainder_size; /* remaining bytes while splitting */
3592 void** marray; /* either "chunks" or malloced ptr array */
3593 mchunkptr array_chunk; /* chunk for malloced ptr array */
3594 flag_t was_enabled; /* to disable mmap */
3598 ensure_initialization();
3599 /* compute array length, if needed */
3601 if (n_elements == 0)
3602 return chunks; /* nothing to do */
3607 /* if empty req, must still return chunk representing empty array */
3608 if (n_elements == 0)
3609 return (void**)internal_malloc(m, 0);
3611 array_size = request2size(n_elements * (sizeof(void*)));
3614 /* compute total element size */
3615 if (opts & 0x1) { /* all-same-size */
3616 element_size = request2size(*sizes);
3617 contents_size = n_elements * element_size;
3619 else { /* add up all the sizes */
3622 for (i = 0; i != n_elements; ++i)
3623 contents_size += request2size(sizes[i]);
3626 size = contents_size + array_size;
3629 Allocate the aggregate chunk. First disable direct-mmapping so
3630 malloc won't use it, since we would not be able to later
3631 free/realloc space internal to a segregated mmap region.
3633 was_enabled = use_mmap(m);
3635 mem = internal_malloc(m, size - CHUNK_OVERHEAD);
3641 if (PREACTION(m)) return 0;
3643 remainder_size = chunksize(p);
3645 assert(!is_mmapped(p));
3647 if (opts & 0x2) { /* optionally clear the elements */
3648 memset((size_t*)mem, 0, remainder_size - SIZE_T_SIZE - array_size);
3651 /* If not provided, allocate the pointer array as final part of chunk */
3653 size_t array_chunk_size;
3654 array_chunk = chunk_plus_offset(p, contents_size);
3655 array_chunk_size = remainder_size - contents_size;
3656 marray = (void**) (chunk2mem(array_chunk));
3657 set_size_and_pinuse_of_inuse_chunk(m, array_chunk, array_chunk_size);
3658 remainder_size = contents_size;
3661 /* split out elements */
3662 for (i = 0; ; ++i) {
3663 marray[i] = chunk2mem(p);
3664 if (i != n_elements-1) {
3665 if (element_size != 0)
3666 size = element_size;
3668 size = request2size(sizes[i]);
3669 remainder_size -= size;
3670 set_size_and_pinuse_of_inuse_chunk(m, p, size);
3671 p = chunk_plus_offset(p, size);
3673 else { /* the final element absorbs any overallocation slop */
3674 set_size_and_pinuse_of_inuse_chunk(m, p, remainder_size);
3680 if (marray != chunks) {
3681 /* final element must have exactly exhausted chunk */
3682 if (element_size != 0) {
3683 assert(remainder_size == element_size);
3686 assert(remainder_size == request2size(sizes[i]));
3688 check_inuse_chunk(m, mem2chunk(marray));
3690 for (i = 0; i != n_elements; ++i)
3691 check_inuse_chunk(m, mem2chunk(marray[i]));
3699 /* Try to free all pointers in the given array.
3700 Note: this could be made faster, by delaying consolidation,
3701 at the price of disabling some user integrity checks, We
3702 still optimize some consolidations by combining adjacent
3703 chunks before freeing, which will occur often if allocated
3704 with ialloc or the array is sorted.
3706 static size_t internal_bulk_free(mstate m, void* array[], size_t nelem) {
3708 if (!PREACTION(m)) {
3710 void** fence = &(array[nelem]);
3711 for (a = array; a != fence; ++a) {
3714 mchunkptr p = mem2chunk(mem);
3715 size_t psize = chunksize(p);
3717 if (get_mstate_for(p) != m) {
3722 check_inuse_chunk(m, p);
3724 if (RTCHECK(ok_address(m, p) && ok_inuse(p))) {
3725 void ** b = a + 1; /* try to merge with next chunk */
3726 mchunkptr next = next_chunk(p);
3727 if (b != fence && *b == chunk2mem(next)) {
3728 size_t newsize = chunksize(next) + psize;
3729 set_inuse(m, p, newsize);
3733 dispose_chunk(m, p, psize);
3736 CORRUPTION_ERROR_ACTION(m);
3741 if (should_trim(m, m->topsize))
3749 #if MALLOC_INSPECT_ALL
3750 static void internal_inspect_all(mstate m,
3751 void(*handler)(void *start,
3754 void* callback_arg),
3756 if (is_initialized(m)) {
3757 mchunkptr top = m->top;
3759 for (s = &m->seg; s != 0; s = s->next) {
3760 mchunkptr q = align_as_chunk(s->base);
3761 while (segment_holds(s, q) && q->head != FENCEPOST_HEAD) {
3762 mchunkptr next = next_chunk(q);
3763 size_t sz = chunksize(q);
3767 used = sz - CHUNK_OVERHEAD; /* must not be mmapped */
3768 start = chunk2mem(q);
3772 if (is_small(sz)) { /* offset by possible bookkeeping */
3773 start = (void*)((char*)q + sizeof(struct malloc_chunk));
3776 start = (void*)((char*)q + sizeof(struct malloc_tree_chunk));
3779 if (start < (void*)next) /* skip if all space is bookkeeping */
3780 handler(start, next, used, arg);
3788 #endif /* MALLOC_INSPECT_ALL */
3790 /* ------------------ Exported realloc, memalign, etc -------------------- */
3794 void* dlrealloc(void* oldmem, size_t bytes) {
3797 mem = dlmalloc(bytes);
3799 else if (bytes >= MAX_REQUEST) {
3800 MALLOC_FAILURE_ACTION;
3802 #ifdef REALLOC_ZERO_BYTES_FREES
3803 else if (bytes == 0) {
3806 #endif /* REALLOC_ZERO_BYTES_FREES */
3808 size_t nb = request2size(bytes);
3809 mchunkptr oldp = mem2chunk(oldmem);
3813 mstate m = get_mstate_for(oldp);
3815 USAGE_ERROR_ACTION(m, oldmem);
3818 #endif /* FOOTERS */
3819 if (!PREACTION(m)) {
3820 mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1);
3823 check_inuse_chunk(m, newp);
3824 mem = chunk2mem(newp);
3827 mem = internal_malloc(m, bytes);
3829 size_t oc = chunksize(oldp) - overhead_for(oldp);
3830 memcpy(mem, oldmem, (oc < bytes)? oc : bytes);
3831 internal_free(m, oldmem);
3839 void* dlrealloc_in_place(void* oldmem, size_t bytes) {
3842 if (bytes >= MAX_REQUEST) {
3843 MALLOC_FAILURE_ACTION;
3846 size_t nb = request2size(bytes);
3847 mchunkptr oldp = mem2chunk(oldmem);
3851 mstate m = get_mstate_for(oldp);
3853 USAGE_ERROR_ACTION(m, oldmem);
3856 #endif /* FOOTERS */
3857 if (!PREACTION(m)) {
3858 mchunkptr newp = try_realloc_chunk(m, oldp, nb, 0);
3861 check_inuse_chunk(m, newp);
3870 void* dlmemalign(size_t alignment, size_t bytes) {
3871 if (alignment <= MALLOC_ALIGNMENT) {
3872 return dlmalloc(bytes);
3874 return internal_memalign(gm, alignment, bytes);
3877 int dlposix_memalign(void** pp, size_t alignment, size_t bytes) {
3879 if (alignment == MALLOC_ALIGNMENT)
3880 mem = dlmalloc(bytes);
3882 size_t d = alignment / sizeof(void*);
3883 size_t r = alignment % sizeof(void*);
3884 if (r != 0 || d == 0 || (d & (d-SIZE_T_ONE)) != 0)
3886 else if (bytes <= MAX_REQUEST - alignment) {
3887 if (alignment < MIN_CHUNK_SIZE)
3888 alignment = MIN_CHUNK_SIZE;
3889 mem = internal_memalign(gm, alignment, bytes);
3900 void* dlvalloc(size_t bytes) {
3902 ensure_initialization();
3903 pagesz = mparams.page_size;
3904 return dlmemalign(pagesz, bytes);
3907 void* dlpvalloc(size_t bytes) {
3909 ensure_initialization();
3910 pagesz = mparams.page_size;
3911 return dlmemalign(pagesz, (bytes + pagesz - SIZE_T_ONE) & ~(pagesz - SIZE_T_ONE));
3914 void** dlindependent_calloc(size_t n_elements, size_t elem_size,
3916 size_t sz = elem_size; /* serves as 1-element array */
3917 return ialloc(gm, n_elements, &sz, 3, chunks);
3920 void** dlindependent_comalloc(size_t n_elements, size_t sizes[],
3922 return ialloc(gm, n_elements, sizes, 0, chunks);
3925 size_t dlbulk_free(void* array[], size_t nelem) {
3926 return internal_bulk_free(gm, array, nelem);
3929 #if MALLOC_INSPECT_ALL
3930 void dlmalloc_inspect_all(void(*handler)(void *start,
3933 void* callback_arg),
3935 ensure_initialization();
3936 if (!PREACTION(gm)) {
3937 internal_inspect_all(gm, handler, arg);
3941 #endif /* MALLOC_INSPECT_ALL */
3943 int dlmalloc_trim(size_t pad) {
3945 ensure_initialization();
3946 if (!PREACTION(gm)) {
3947 result = sys_trim(gm, pad);
3953 size_t dlmalloc_footprint(void) {
3954 return gm->footprint;
3957 size_t dlmalloc_max_footprint(void) {
3958 return gm->max_footprint;
3961 size_t dlmalloc_footprint_limit(void) {
3962 size_t maf = gm->footprint_limit;
3963 return maf == 0 ? MAX_SIZE_T : maf;
3966 size_t dlmalloc_set_footprint_limit(size_t bytes) {
3967 size_t result; /* invert sense of 0 */
3969 result = granularity_align(1); /* Use minimal size */
3970 if (bytes == MAX_SIZE_T)
3971 result = 0; /* disable */
3973 result = granularity_align(bytes);
3974 return gm->footprint_limit = result;
3978 struct dlmallinfo dlmallinfo(void) {
3979 return internal_mallinfo(gm);
3981 #endif /* NO_MALLINFO */
3983 #if !NO_MALLOC_STATS
3984 void dlmalloc_stats() {
3985 internal_malloc_stats(gm);
3987 #endif /* NO_MALLOC_STATS */
3989 int dlmallopt(int param_number, int value) {
3990 return change_mparam(param_number, value);
3993 size_t dlmalloc_usable_size(void* mem) {
3995 mchunkptr p = mem2chunk(mem);
3997 return chunksize(p) - overhead_for(p);
4002 #endif /* !ONLY_MSPACES */
4004 /* ----------------------------- user mspaces ---------------------------- */
4008 static mstate init_user_mstate(char* tbase, size_t tsize) {
4009 size_t msize = pad_request(sizeof(struct malloc_state));
4011 mchunkptr msp = align_as_chunk(tbase);
4012 mstate m = (mstate)(chunk2mem(msp));
4013 memset(m, 0, msize);
4014 (void)INITIAL_LOCK(&m->mutex);
4015 msp->head = (msize|INUSE_BITS);
4016 m->seg.base = m->least_addr = tbase;
4017 m->seg.size = m->footprint = m->max_footprint = tsize;
4018 m->magic = mparams.magic;
4019 m->release_checks = MAX_RELEASE_CHECK_RATE;
4020 m->mflags = mparams.default_mflags;
4023 disable_contiguous(m);
4025 mn = next_chunk(mem2chunk(m));
4026 init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) - TOP_FOOT_SIZE);
4027 check_top_chunk(m, m->top);
4031 mspace create_mspace(size_t capacity, int locked) {
4034 ensure_initialization();
4035 msize = pad_request(sizeof(struct malloc_state));
4036 if (capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
4037 size_t rs = ((capacity == 0)? mparams.granularity :
4038 (capacity + TOP_FOOT_SIZE + msize));
4039 size_t tsize = granularity_align(rs);
4040 char* tbase = (char*)(CALL_MMAP(tsize));
4041 if (tbase != CMFAIL) {
4042 m = init_user_mstate(tbase, tsize);
4043 m->seg.sflags = USE_MMAP_BIT;
4044 set_lock(m, locked);
4050 mspace create_mspace_with_base(void* base, size_t capacity, int locked) {
4053 ensure_initialization();
4054 msize = pad_request(sizeof(struct malloc_state));
4055 if (capacity > msize + TOP_FOOT_SIZE &&
4056 capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
4057 m = init_user_mstate((char*)base, capacity);
4058 m->seg.sflags = EXTERN_BIT;
4059 set_lock(m, locked);
4064 int mspace_track_large_chunks(mspace msp, int enable) {
4066 mstate ms = (mstate)msp;
4067 if (!PREACTION(ms)) {
4068 if (!use_mmap(ms)) {
4081 size_t destroy_mspace(mspace msp) {
4083 mstate ms = (mstate)msp;
4085 msegmentptr sp = &ms->seg;
4086 (void)DESTROY_LOCK(&ms->mutex); /* destroy before unmapped */
4088 char* base = sp->base;
4089 size_t size = sp->size;
4090 flag_t flag = sp->sflags;
4091 (void)base; /* placate people compiling -Wunused-variable */
4093 if ((flag & USE_MMAP_BIT) && !(flag & EXTERN_BIT) &&
4094 CALL_MUNMAP(base, size) == 0)
4099 USAGE_ERROR_ACTION(ms,ms);
4104 void mspace_get_address_and_size (mspace msp, char **addrp, size_t *sizep)
4110 this_seg = &ms->seg;
4112 *addrp = this_seg->base;
4113 *sizep = this_seg->size;
4116 CLIB_NOSANITIZE_ADDR
4117 int mspace_is_heap_object (mspace msp, void *p)
4125 this_seg = &ms->seg;
4130 base = this_seg->base;
4131 if (pp >= base && pp < (base + this_seg->size))
4133 this_seg = this_seg->next;
4136 if (pp > ms->least_addr && pp <= ms->least_addr + ms->footprint)
4142 void *mspace_least_addr (mspace msp)
4144 mstate ms = (mstate) msp;
4145 return (void *) ms->least_addr;
4148 void mspace_disable_expand (mspace msp)
4150 mstate ms = (mstate)msp;
4152 disable_expand (ms);
4155 int mspace_enable_disable_trace (mspace msp, int enable)
4157 mstate ms = (mstate)msp;
4158 int was_enabled = 0;
4168 return (was_enabled);
4171 CLIB_NOSANITIZE_ADDR
4172 int mspace_is_traced (mspace msp)
4174 mstate ms = (mstate)msp;
4181 CLIB_NOSANITIZE_ADDR
4182 void* mspace_get_aligned (mspace msp,
4183 unsigned long n_user_data_bytes,
4184 unsigned long align,
4185 unsigned long align_offset) {
4187 unsigned long searchp;
4188 unsigned *wwp; /* "where's Waldo" pointer */
4189 mstate ms = (mstate)msp;
4192 * Allocate space for the "Where's Waldo?" pointer
4193 * the base of the dlmalloc object
4195 n_user_data_bytes += sizeof(unsigned);
4198 * Alignment requests less than the size of an mmx vector are ignored
4200 if (align < sizeof (uword)) {
4201 rv = mspace_malloc (msp, n_user_data_bytes);
4205 if (use_trace(ms)) {
4206 mchunkptr p = mem2chunk(rv);
4207 size_t psize = chunksize(p);
4209 mheap_get_trace ((unsigned long)rv + sizeof (unsigned), psize);
4212 wwp = (unsigned *)rv;
4214 rv += sizeof (unsigned);
4220 * Alignment requests greater than 4K must be at offset zero,
4221 * and must be freed using mspace_free_no_offset - or never freed -
4222 * since the "Where's Waldo?" pointer would waste too much space.
4224 * Waldo is the address of the chunk of memory returned by mspace_malloc,
4225 * which we need later to call mspace_free...
4227 if (align > 4<<10 || align_offset == ~0UL) {
4228 n_user_data_bytes -= sizeof(unsigned);
4229 assert(align_offset == 0);
4230 rv = internal_memalign(ms, (size_t)align, n_user_data_bytes);
4232 /* Trace the allocation */
4233 if (rv && use_trace(ms)) {
4234 mchunkptr p = mem2chunk(rv);
4235 size_t psize = chunksize(p);
4236 mheap_get_trace ((unsigned long)rv, psize);
4241 align = clib_max (align, MALLOC_ALIGNMENT);
4242 align = max_pow2 (align);
4244 /* Correct align offset to be smaller than alignment. */
4245 align_offset &= (align - 1);
4247 n_user_data_bytes += align;
4248 rv = mspace_malloc (msp, n_user_data_bytes);
4253 /* Honor the alignment request */
4254 searchp = (unsigned long)(rv + sizeof (unsigned));
4256 #if 0 /* this is the idea... */
4257 while ((searchp + align_offset) % align)
4262 unsigned long where_now, delta;
4264 where_now = (searchp + align_offset) % align;
4265 delta = align - where_now;
4270 wwp = (unsigned *)(searchp - sizeof(unsigned));
4271 *wwp = (searchp - (((unsigned long) rv) + sizeof (*wwp)));
4272 assert (*wwp < align);
4274 if (use_trace(ms)) {
4275 mchunkptr p = mem2chunk(rv);
4276 size_t psize = chunksize(p);
4277 mheap_get_trace (searchp, psize);
4279 return (void *) searchp;
4282 CLIB_NOSANITIZE_ADDR
4283 void mspace_put (mspace msp, void *p_arg)
4285 char *object_header;
4287 mstate ms = (mstate)msp;
4289 /* Find the object header delta */
4290 wwp = (unsigned *)p_arg;
4293 /* Recover the dlmalloc object pointer */
4294 object_header = (char *)wwp;
4295 object_header -= *wwp;
4297 /* Tracing (if enabled) */
4300 mchunkptr p = mem2chunk(object_header);
4301 size_t psize = chunksize(p);
4303 mheap_put_trace ((unsigned long)p_arg, psize);
4306 #if CLIB_DEBUG > 0 && !defined(CLIB_SANITIZE_ADDR)
4307 /* Poison the object */
4309 size_t psize = mspace_usable_size (object_header);
4310 memset (object_header, 0x13, psize);
4314 /* And free it... */
4315 mspace_free (msp, object_header);
4318 void mspace_put_no_offset (mspace msp, void *p_arg)
4320 mstate ms = (mstate)msp;
4324 mchunkptr p = mem2chunk(p_arg);
4325 size_t psize = chunksize(p);
4327 mheap_put_trace ((unsigned long)p_arg, psize);
4329 mspace_free (msp, p_arg);
4332 CLIB_NOSANITIZE_ADDR
4333 size_t mspace_usable_size_with_delta (const void *p)
4336 char *object_header;
4339 /* Find the object header delta */
4340 wwp = (unsigned *)p;
4343 /* Recover the dlmalloc object pointer */
4344 object_header = (char *)wwp;
4345 object_header -= *wwp;
4347 usable_size = mspace_usable_size (object_header);
4348 /* account for the offset and the size of the offset... */
4349 usable_size -= (*wwp + sizeof (*wwp));
4354 mspace versions of routines are near-clones of the global
4355 versions. This is not so nice but better than the alternatives.
4358 CLIB_NOSANITIZE_ADDR
4359 void* mspace_malloc(mspace msp, size_t bytes) {
4360 mstate ms = (mstate)msp;
4361 if (!ok_magic(ms)) {
4362 USAGE_ERROR_ACTION(ms,ms);
4365 if (!PREACTION(ms)) {
4368 if (bytes <= MAX_SMALL_REQUEST) {
4371 nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
4372 idx = small_index(nb);
4373 smallbits = ms->smallmap >> idx;
4375 if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
4377 idx += ~smallbits & 1; /* Uses next bin if idx empty */
4378 b = smallbin_at(ms, idx);
4380 assert(chunksize(p) == small_index2size(idx));
4381 unlink_first_small_chunk(ms, b, p, idx);
4382 set_inuse_and_pinuse(ms, p, small_index2size(idx));
4384 check_malloced_chunk(ms, mem, nb);
4388 else if (nb > ms->dvsize) {
4389 if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
4393 binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
4394 binmap_t leastbit = least_bit(leftbits);
4395 compute_bit2idx(leastbit, i);
4396 b = smallbin_at(ms, i);
4398 assert(chunksize(p) == small_index2size(i));
4399 unlink_first_small_chunk(ms, b, p, i);
4400 rsize = small_index2size(i) - nb;
4401 /* Fit here cannot be remainderless if 4byte sizes */
4402 if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
4403 set_inuse_and_pinuse(ms, p, small_index2size(i));
4405 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
4406 r = chunk_plus_offset(p, nb);
4407 set_size_and_pinuse_of_free_chunk(r, rsize);
4408 replace_dv(ms, r, rsize);
4411 check_malloced_chunk(ms, mem, nb);
4415 else if (ms->treemap != 0 && (mem = tmalloc_small(ms, nb)) != 0) {
4416 check_malloced_chunk(ms, mem, nb);
4421 else if (bytes >= MAX_REQUEST)
4422 nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
4424 nb = pad_request(bytes);
4425 if (ms->treemap != 0 && (mem = tmalloc_large(ms, nb)) != 0) {
4426 check_malloced_chunk(ms, mem, nb);
4431 if (nb <= ms->dvsize) {
4432 size_t rsize = ms->dvsize - nb;
4433 mchunkptr p = ms->dv;
4434 if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
4435 mchunkptr r = ms->dv = chunk_plus_offset(p, nb);
4437 set_size_and_pinuse_of_free_chunk(r, rsize);
4438 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
4440 else { /* exhaust dv */
4441 size_t dvs = ms->dvsize;
4444 set_inuse_and_pinuse(ms, p, dvs);
4447 check_malloced_chunk(ms, mem, nb);
4451 else if (nb < ms->topsize) { /* Split top */
4452 size_t rsize = ms->topsize -= nb;
4453 mchunkptr p = ms->top;
4454 mchunkptr r = ms->top = chunk_plus_offset(p, nb);
4455 r->head = rsize | PINUSE_BIT;
4456 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
4458 check_top_chunk(ms, ms->top);
4459 check_malloced_chunk(ms, mem, nb);
4463 mem = sys_alloc(ms, nb);
4473 CLIB_NOSANITIZE_ADDR
4474 void mspace_free(mspace msp, void* mem) {
4476 mchunkptr p = mem2chunk(mem);
4478 mstate fm = get_mstate_for(p);
4479 (void)msp; /* placate people compiling -Wunused */
4481 mstate fm = (mstate)msp;
4482 #endif /* FOOTERS */
4483 if (!ok_magic(fm)) {
4484 USAGE_ERROR_ACTION(fm, p);
4487 if (!PREACTION(fm)) {
4488 check_inuse_chunk(fm, p);
4489 if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
4490 size_t psize = chunksize(p);
4491 mchunkptr next = chunk_plus_offset(p, psize);
4493 size_t prevsize = p->prev_foot;
4494 if (is_mmapped(p)) {
4495 psize += prevsize + MMAP_FOOT_PAD;
4496 if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
4497 fm->footprint -= psize;
4501 mchunkptr prev = chunk_minus_offset(p, prevsize);
4504 if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
4506 unlink_chunk(fm, p, prevsize);
4508 else if ((next->head & INUSE_BITS) == INUSE_BITS) {
4510 set_free_with_pinuse(p, psize, next);
4519 if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
4520 if (!cinuse(next)) { /* consolidate forward */
4521 if (next == fm->top) {
4522 size_t tsize = fm->topsize += psize;
4524 p->head = tsize | PINUSE_BIT;
4529 if (should_trim(fm, tsize))
4533 else if (next == fm->dv) {
4534 size_t dsize = fm->dvsize += psize;
4536 set_size_and_pinuse_of_free_chunk(p, dsize);
4540 size_t nsize = chunksize(next);
4542 unlink_chunk(fm, next, nsize);
4543 set_size_and_pinuse_of_free_chunk(p, psize);
4551 set_free_with_pinuse(p, psize, next);
4553 if (is_small(psize)) {
4554 insert_small_chunk(fm, p, psize);
4555 check_free_chunk(fm, p);
4558 tchunkptr tp = (tchunkptr)p;
4559 insert_large_chunk(fm, tp, psize);
4560 check_free_chunk(fm, p);
4561 if (--fm->release_checks == 0)
4562 release_unused_segments(fm);
4568 USAGE_ERROR_ACTION(fm, p);
4575 void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size) {
4578 mstate ms = (mstate)msp;
4579 if (!ok_magic(ms)) {
4580 USAGE_ERROR_ACTION(ms,ms);
4583 if (n_elements != 0) {
4584 req = n_elements * elem_size;
4585 if (((n_elements | elem_size) & ~(size_t)0xffff) &&
4586 (req / n_elements != elem_size))
4587 req = MAX_SIZE_T; /* force downstream failure on overflow */
4589 mem = internal_malloc(ms, req);
4590 if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
4591 memset(mem, 0, req);
4595 void* mspace_realloc(mspace msp, void* oldmem, size_t bytes) {
4598 mem = mspace_malloc(msp, bytes);
4600 else if (bytes >= MAX_REQUEST) {
4601 MALLOC_FAILURE_ACTION;
4603 #ifdef REALLOC_ZERO_BYTES_FREES
4604 else if (bytes == 0) {
4605 mspace_free(msp, oldmem);
4607 #endif /* REALLOC_ZERO_BYTES_FREES */
4609 size_t nb = request2size(bytes);
4610 mchunkptr oldp = mem2chunk(oldmem);
4612 mstate m = (mstate)msp;
4614 mstate m = get_mstate_for(oldp);
4616 USAGE_ERROR_ACTION(m, oldmem);
4619 #endif /* FOOTERS */
4620 if (!PREACTION(m)) {
4621 mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1);
4624 check_inuse_chunk(m, newp);
4625 mem = chunk2mem(newp);
4628 mem = mspace_malloc(m, bytes);
4630 size_t oc = chunksize(oldp) - overhead_for(oldp);
4631 memcpy(mem, oldmem, (oc < bytes)? oc : bytes);
4632 mspace_free(m, oldmem);
4640 void* mspace_realloc_in_place(mspace msp, void* oldmem, size_t bytes) {
4643 if (bytes >= MAX_REQUEST) {
4644 MALLOC_FAILURE_ACTION;
4647 size_t nb = request2size(bytes);
4648 mchunkptr oldp = mem2chunk(oldmem);
4650 mstate m = (mstate)msp;
4652 mstate m = get_mstate_for(oldp);
4653 (void)msp; /* placate people compiling -Wunused */
4655 USAGE_ERROR_ACTION(m, oldmem);
4658 #endif /* FOOTERS */
4659 if (!PREACTION(m)) {
4660 mchunkptr newp = try_realloc_chunk(m, oldp, nb, 0);
4663 check_inuse_chunk(m, newp);
4672 void* mspace_memalign(mspace msp, size_t alignment, size_t bytes) {
4673 mstate ms = (mstate)msp;
4674 if (!ok_magic(ms)) {
4675 USAGE_ERROR_ACTION(ms,ms);
4678 if (alignment <= MALLOC_ALIGNMENT)
4679 return mspace_malloc(msp, bytes);
4680 return internal_memalign(ms, alignment, bytes);
4683 void** mspace_independent_calloc(mspace msp, size_t n_elements,
4684 size_t elem_size, void* chunks[]) {
4685 size_t sz = elem_size; /* serves as 1-element array */
4686 mstate ms = (mstate)msp;
4687 if (!ok_magic(ms)) {
4688 USAGE_ERROR_ACTION(ms,ms);
4691 return ialloc(ms, n_elements, &sz, 3, chunks);
4694 void** mspace_independent_comalloc(mspace msp, size_t n_elements,
4695 size_t sizes[], void* chunks[]) {
4696 mstate ms = (mstate)msp;
4697 if (!ok_magic(ms)) {
4698 USAGE_ERROR_ACTION(ms,ms);
4701 return ialloc(ms, n_elements, sizes, 0, chunks);
4704 size_t mspace_bulk_free(mspace msp, void* array[], size_t nelem) {
4705 return internal_bulk_free((mstate)msp, array, nelem);
4708 #if MALLOC_INSPECT_ALL
4709 void mspace_inspect_all(mspace msp,
4710 void(*handler)(void *start,
4713 void* callback_arg),
4715 mstate ms = (mstate)msp;
4717 if (!PREACTION(ms)) {
4718 internal_inspect_all(ms, handler, arg);
4723 USAGE_ERROR_ACTION(ms,ms);
4726 #endif /* MALLOC_INSPECT_ALL */
4728 int mspace_trim(mspace msp, size_t pad) {
4730 mstate ms = (mstate)msp;
4732 if (!PREACTION(ms)) {
4733 result = sys_trim(ms, pad);
4738 USAGE_ERROR_ACTION(ms,ms);
4743 #if !NO_MALLOC_STATS
4744 void mspace_malloc_stats(mspace msp) {
4745 mstate ms = (mstate)msp;
4747 internal_malloc_stats(ms);
4750 USAGE_ERROR_ACTION(ms,ms);
4753 #endif /* NO_MALLOC_STATS */
4755 size_t mspace_footprint(mspace msp) {
4757 mstate ms = (mstate)msp;
4759 result = ms->footprint;
4762 USAGE_ERROR_ACTION(ms,ms);
4767 size_t mspace_max_footprint(mspace msp) {
4769 mstate ms = (mstate)msp;
4771 result = ms->max_footprint;
4774 USAGE_ERROR_ACTION(ms,ms);
4779 size_t mspace_footprint_limit(mspace msp) {
4781 mstate ms = (mstate)msp;
4783 size_t maf = ms->footprint_limit;
4784 result = (maf == 0) ? MAX_SIZE_T : maf;
4787 USAGE_ERROR_ACTION(ms,ms);
4792 size_t mspace_set_footprint_limit(mspace msp, size_t bytes) {
4794 mstate ms = (mstate)msp;
4797 result = granularity_align(1); /* Use minimal size */
4798 if (bytes == MAX_SIZE_T)
4799 result = 0; /* disable */
4801 result = granularity_align(bytes);
4802 ms->footprint_limit = result;
4805 USAGE_ERROR_ACTION(ms,ms);
4811 CLIB_NOSANITIZE_ADDR
4812 struct dlmallinfo mspace_mallinfo(mspace msp) {
4813 mstate ms = (mstate)msp;
4814 if (!ok_magic(ms)) {
4815 USAGE_ERROR_ACTION(ms,ms);
4817 return internal_mallinfo(ms);
4819 #endif /* NO_MALLINFO */
4821 CLIB_NOSANITIZE_ADDR
4822 size_t mspace_usable_size(const void* mem) {
4824 mchunkptr p = mem2chunk(mem);
4826 return chunksize(p) - overhead_for(p);
4831 int mspace_mallopt(int param_number, int value) {
4832 return change_mparam(param_number, value);
4835 #endif /* MSPACES */
4838 /* -------------------- Alternative MORECORE functions ------------------- */
4841 Guidelines for creating a custom version of MORECORE:
4843 * For best performance, MORECORE should allocate in multiples of pagesize.
4844 * MORECORE may allocate more memory than requested. (Or even less,
4845 but this will usually result in a malloc failure.)
4846 * MORECORE must not allocate memory when given argument zero, but
4847 instead return one past the end address of memory from previous
4849 * For best performance, consecutive calls to MORECORE with positive
4850 arguments should return increasing addresses, indicating that
4851 space has been contiguously extended.
4852 * Even though consecutive calls to MORECORE need not return contiguous
4853 addresses, it must be OK for malloc'ed chunks to span multiple
4854 regions in those cases where they do happen to be contiguous.
4855 * MORECORE need not handle negative arguments -- it may instead
4856 just return MFAIL when given negative arguments.
4857 Negative arguments are always multiples of pagesize. MORECORE
4858 must not misinterpret negative args as large positive unsigned
4859 args. You can suppress all such calls from even occurring by defining
4860 MORECORE_CANNOT_TRIM,
4862 As an example alternative MORECORE, here is a custom allocator
4863 kindly contributed for pre-OSX macOS. It uses virtually but not
4864 necessarily physically contiguous non-paged memory (locked in,
4865 present and won't get swapped out). You can use it by uncommenting
4866 this section, adding some #includes, and setting up the appropriate
4869 #define MORECORE osMoreCore
4871 There is also a shutdown routine that should somehow be called for
4872 cleanup upon program exit.
4874 #define MAX_POOL_ENTRIES 100
4875 #define MINIMUM_MORECORE_SIZE (64 * 1024U)
4876 static int next_os_pool;
4877 void *our_os_pools[MAX_POOL_ENTRIES];
4879 void *osMoreCore(int size)
4882 static void *sbrk_top = 0;
4886 if (size < MINIMUM_MORECORE_SIZE)
4887 size = MINIMUM_MORECORE_SIZE;
4888 if (CurrentExecutionLevel() == kTaskLevel)
4889 ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
4892 return (void *) MFAIL;
4894 // save ptrs so they can be freed during cleanup
4895 our_os_pools[next_os_pool] = ptr;
4897 ptr = (void *) ((((size_t) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
4898 sbrk_top = (char *) ptr + size;
4903 // we don't currently support shrink behavior
4904 return (void *) MFAIL;
4912 // cleanup any allocated memory pools
4913 // called as last thing before shutting down driver
4915 void osCleanupMem(void)
4919 for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
4922 PoolDeallocate(*ptr);
4930 /* -----------------------------------------------------------------------
4932 v2.8.6 Wed Aug 29 06:57:58 2012 Doug Lea
4933 * fix bad comparison in dlposix_memalign
4934 * don't reuse adjusted asize in sys_alloc
4935 * add LOCK_AT_FORK -- thanks to Kirill Artamonov for the suggestion
4936 * reduce compiler warnings -- thanks to all who reported/suggested these
4938 v2.8.5 Sun May 22 10:26:02 2011 Doug Lea (dl at gee)
4939 * Always perform unlink checks unless INSECURE
4940 * Add posix_memalign.
4941 * Improve realloc to expand in more cases; expose realloc_in_place.
4942 Thanks to Peter Buhr for the suggestion.
4943 * Add footprint_limit, inspect_all, bulk_free. Thanks
4944 to Barry Hayes and others for the suggestions.
4945 * Internal refactorings to avoid calls while holding locks
4946 * Use non-reentrant locks by default. Thanks to Roland McGrath
4948 * Small fixes to mspace_destroy, reset_on_error.
4949 * Various configuration extensions/changes. Thanks
4950 to all who contributed these.
4952 V2.8.4a Thu Apr 28 14:39:43 2011 (dl at gee.cs.oswego.edu)
4953 * Update Creative Commons URL
4955 V2.8.4 Wed May 27 09:56:23 2009 Doug Lea (dl at gee)
4956 * Use zeros instead of prev foot for is_mmapped
4957 * Add mspace_track_large_chunks; thanks to Jean Brouwers
4958 * Fix set_inuse in internal_realloc; thanks to Jean Brouwers
4959 * Fix insufficient sys_alloc padding when using 16byte alignment
4960 * Fix bad error check in mspace_footprint
4961 * Adaptations for ptmalloc; thanks to Wolfram Gloger.
4962 * Reentrant spin locks; thanks to Earl Chew and others
4963 * Win32 improvements; thanks to Niall Douglas and Earl Chew
4964 * Add NO_SEGMENT_TRAVERSAL and MAX_RELEASE_CHECK_RATE options
4965 * Extension hook in malloc_state
4966 * Various small adjustments to reduce warnings on some compilers
4967 * Various configuration extensions/changes for more platforms. Thanks
4968 to all who contributed these.
4970 V2.8.3 Thu Sep 22 11:16:32 2005 Doug Lea (dl at gee)
4971 * Add max_footprint functions
4972 * Ensure all appropriate literals are size_t
4973 * Fix conditional compilation problem for some #define settings
4974 * Avoid concatenating segments with the one provided
4975 in create_mspace_with_base
4976 * Rename some variables to avoid compiler shadowing warnings
4977 * Use explicit lock initialization.
4978 * Better handling of sbrk interference.
4979 * Simplify and fix segment insertion, trimming and mspace_destroy
4980 * Reinstate REALLOC_ZERO_BYTES_FREES option from 2.7.x
4981 * Thanks especially to Dennis Flanagan for help on these.
4983 V2.8.2 Sun Jun 12 16:01:10 2005 Doug Lea (dl at gee)
4984 * Fix memalign brace error.
4986 V2.8.1 Wed Jun 8 16:11:46 2005 Doug Lea (dl at gee)
4987 * Fix improper #endif nesting in C++
4988 * Add explicit casts needed for C++
4990 V2.8.0 Mon May 30 14:09:02 2005 Doug Lea (dl at gee)
4991 * Use trees for large bins
4993 * Use segments to unify sbrk-based and mmap-based system allocation,
4994 removing need for emulation on most platforms without sbrk.
4995 * Default safety checks
4996 * Optional footer checks. Thanks to William Robertson for the idea.
4997 * Internal code refactoring
4998 * Incorporate suggestions and platform-specific changes.
4999 Thanks to Dennis Flanagan, Colin Plumb, Niall Douglas,
5000 Aaron Bachmann, Emery Berger, and others.
5001 * Speed up non-fastbin processing enough to remove fastbins.
5002 * Remove useless cfree() to avoid conflicts with other apps.
5003 * Remove internal memcpy, memset. Compilers handle builtins better.
5004 * Remove some options that no one ever used and rename others.
5006 V2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
5007 * Fix malloc_state bitmap array misdeclaration
5009 V2.7.1 Thu Jul 25 10:58:03 2002 Doug Lea (dl at gee)
5010 * Allow tuning of FIRST_SORTED_BIN_SIZE
5011 * Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte.
5012 * Better detection and support for non-contiguousness of MORECORE.
5013 Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger
5014 * Bypass most of malloc if no frees. Thanks To Emery Berger.
5015 * Fix freeing of old top non-contiguous chunk im sysmalloc.
5016 * Raised default trim and map thresholds to 256K.
5017 * Fix mmap-related #defines. Thanks to Lubos Lunak.
5018 * Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield.
5019 * Branch-free bin calculation
5020 * Default trim and mmap thresholds now 256K.
5022 V2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee)
5023 * Introduce independent_comalloc and independent_calloc.
5024 Thanks to Michael Pachos for motivation and help.
5025 * Make optional .h file available
5026 * Allow > 2GB requests on 32bit systems.
5027 * new WIN32 sbrk, mmap, munmap, lock code from <Walter@GeNeSys-e.de>.
5028 Thanks also to Andreas Mueller <a.mueller at paradatec.de>,
5030 * Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for
5032 * memalign: check alignment arg
5033 * realloc: don't try to shift chunks backwards, since this
5034 leads to more fragmentation in some programs and doesn't
5035 seem to help in any others.
5036 * Collect all cases in malloc requiring system memory into sysmalloc
5037 * Use mmap as backup to sbrk
5038 * Place all internal state in malloc_state
5039 * Introduce fastbins (although similar to 2.5.1)
5040 * Many minor tunings and cosmetic improvements
5041 * Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK
5042 * Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
5043 Thanks to Tony E. Bennett <tbennett@nvidia.com> and others.
5044 * Include errno.h to support default failure action.
5046 V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
5047 * return null for negative arguments
5048 * Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
5049 * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
5050 (e.g. WIN32 platforms)
5051 * Cleanup header file inclusion for WIN32 platforms
5052 * Cleanup code to avoid Microsoft Visual C++ compiler complaints
5053 * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
5054 memory allocation routines
5055 * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
5056 * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
5057 usage of 'assert' in non-WIN32 code
5058 * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
5060 * Always call 'fREe()' rather than 'free()'
5062 V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
5063 * Fixed ordering problem with boundary-stamping
5065 V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee)
5066 * Added pvalloc, as recommended by H.J. Liu
5067 * Added 64bit pointer support mainly from Wolfram Gloger
5068 * Added anonymously donated WIN32 sbrk emulation
5069 * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
5070 * malloc_extend_top: fix mask error that caused wastage after
5072 * Add linux mremap support code from HJ Liu
5074 V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee)
5075 * Integrated most documentation with the code.
5076 * Add support for mmap, with help from
5077 Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
5078 * Use last_remainder in more cases.
5079 * Pack bins using idea from colin@nyx10.cs.du.edu
5080 * Use ordered bins instead of best-fit threshold
5081 * Eliminate block-local decls to simplify tracing and debugging.
5082 * Support another case of realloc via move into top
5083 * Fix error occurring when initial sbrk_base not word-aligned.
5084 * Rely on page size for units instead of SBRK_UNIT to
5085 avoid surprises about sbrk alignment conventions.
5086 * Add mallinfo, mallopt. Thanks to Raymond Nijssen
5087 (raymond@es.ele.tue.nl) for the suggestion.
5088 * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
5089 * More precautions for cases where other routines call sbrk,
5090 courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
5091 * Added macros etc., allowing use in linux libc from
5092 H.J. Lu (hjl@gnu.ai.mit.edu)
5093 * Inverted this history list
5095 V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee)
5096 * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
5097 * Removed all preallocation code since under current scheme
5098 the work required to undo bad preallocations exceeds
5099 the work saved in good cases for most test programs.
5100 * No longer use return list or unconsolidated bins since
5101 no scheme using them consistently outperforms those that don't
5102 given above changes.
5103 * Use best fit for very large chunks to prevent some worst-cases.
5104 * Added some support for debugging
5106 V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee)
5107 * Removed footers when chunks are in use. Thanks to
5108 Paul Wilson (wilson@cs.texas.edu) for the suggestion.
5110 V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee)
5111 * Added malloc_trim, with help from Wolfram Gloger
5112 (wmglo@Dent.MED.Uni-Muenchen.DE).
5114 V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g)
5116 V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g)
5117 * realloc: try to expand in both directions
5118 * malloc: swap order of clean-bin strategy;
5119 * realloc: only conditionally expand backwards
5120 * Try not to scavenge used bins
5121 * Use bin counts as a guide to preallocation
5122 * Occasionally bin return list chunks in first scan
5123 * Add a few optimizations from colin@nyx10.cs.du.edu
5125 V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g)
5126 * faster bin computation & slightly different binning
5127 * merged all consolidations to one part of malloc proper
5128 (eliminating old malloc_find_space & malloc_clean_bin)
5129 * Scan 2 returns chunks (not just 1)
5130 * Propagate failure in realloc if malloc returns 0
5131 * Add stuff to allow compilation on non-ANSI compilers
5132 from kpv@research.att.com
5134 V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu)
5135 * removed potential for odd address access in prev_chunk
5136 * removed dependency on getpagesize.h
5137 * misc cosmetics and a bit more internal documentation
5138 * anticosmetics: mangled names in macros to evade debugger strangeness
5139 * tested on sparc, hp-700, dec-mips, rs6000
5140 with gcc & native cc (hp, dec only) allowing
5141 Detlefs & Zorn comparison study (in SIGPLAN Notices.)
5143 Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu)
5144 * Based loosely on libg++-1.2X malloc. (It retains some of the overall
5145 structure of old version, but most details differ.)