4 #if CONFIG_IS_ENABLED(UNIT_TEST)
13 static void malloc_update_mallinfo (void);
14 void malloc_stats (void);
16 static void malloc_update_mallinfo ();
21 DECLARE_GLOBAL_DATA_PTR;
24 Emulation of sbrk for WIN32
25 All code within the ifdef WIN32 is untested by me.
27 Thanks to Martin Fong and others for supplying this.
33 #define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \
34 ~(malloc_getpagesize-1))
35 #define AlignPage64K(add) (((add) + (0x10000 - 1)) & ~(0x10000 - 1))
37 /* resrve 64MB to insure large contiguous space */
38 #define RESERVED_SIZE (1024*1024*64)
39 #define NEXT_SIZE (2048*1024)
40 #define TOP_MEMORY ((unsigned long)2*1024*1024*1024)
43 typedef struct GmListElement GmListElement;
51 static GmListElement* head = 0;
52 static unsigned int gNextAddress = 0;
53 static unsigned int gAddressBase = 0;
54 static unsigned int gAllocatedSize = 0;
57 GmListElement* makeGmListElement (void* bas)
60 this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement));
74 assert ( (head == NULL) || (head->base == (void*)gAddressBase));
75 if (gAddressBase && (gNextAddress - gAddressBase))
77 rval = VirtualFree ((void*)gAddressBase,
78 gNextAddress - gAddressBase,
84 GmListElement* next = head->next;
85 rval = VirtualFree (head->base, 0, MEM_RELEASE);
93 void* findRegion (void* start_address, unsigned long size)
95 MEMORY_BASIC_INFORMATION info;
96 if (size >= TOP_MEMORY) return NULL;
98 while ((unsigned long)start_address + size < TOP_MEMORY)
100 VirtualQuery (start_address, &info, sizeof (info));
101 if ((info.State == MEM_FREE) && (info.RegionSize >= size))
102 return start_address;
105 /* Requested region is not available so see if the */
106 /* next region is available. Set 'start_address' */
107 /* to the next region and call 'VirtualQuery()' */
110 start_address = (char*)info.BaseAddress + info.RegionSize;
112 /* Make sure we start looking for the next region */
113 /* on the *next* 64K boundary. Otherwise, even if */
114 /* the new region is free according to */
115 /* 'VirtualQuery()', the subsequent call to */
116 /* 'VirtualAlloc()' (which follows the call to */
117 /* this routine in 'wsbrk()') will round *down* */
118 /* the requested address to a 64K boundary which */
119 /* we already know is an address in the */
120 /* unavailable region. Thus, the subsequent call */
121 /* to 'VirtualAlloc()' will fail and bring us back */
122 /* here, causing us to go into an infinite loop. */
125 (void *) AlignPage64K((unsigned long) start_address);
133 void* wsbrk (long size)
138 if (gAddressBase == 0)
140 gAllocatedSize = max (RESERVED_SIZE, AlignPage (size));
141 gNextAddress = gAddressBase =
142 (unsigned int)VirtualAlloc (NULL, gAllocatedSize,
143 MEM_RESERVE, PAGE_NOACCESS);
144 } else if (AlignPage (gNextAddress + size) > (gAddressBase +
147 long new_size = max (NEXT_SIZE, AlignPage (size));
148 void* new_address = (void*)(gAddressBase+gAllocatedSize);
151 new_address = findRegion (new_address, new_size);
156 gAddressBase = gNextAddress =
157 (unsigned int)VirtualAlloc (new_address, new_size,
158 MEM_RESERVE, PAGE_NOACCESS);
159 /* repeat in case of race condition */
160 /* The region that we found has been snagged */
161 /* by another thread */
163 while (gAddressBase == 0);
165 assert (new_address == (void*)gAddressBase);
167 gAllocatedSize = new_size;
169 if (!makeGmListElement ((void*)gAddressBase))
172 if ((size + gNextAddress) > AlignPage (gNextAddress))
175 res = VirtualAlloc ((void*)AlignPage (gNextAddress),
176 (size + gNextAddress -
177 AlignPage (gNextAddress)),
178 MEM_COMMIT, PAGE_READWRITE);
182 tmp = (void*)gNextAddress;
183 gNextAddress = (unsigned int)tmp + size;
188 unsigned int alignedGoal = AlignPage (gNextAddress + size);
189 /* Trim by releasing the virtual memory */
190 if (alignedGoal >= gAddressBase)
192 VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal,
194 gNextAddress = gNextAddress + size;
195 return (void*)gNextAddress;
199 VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase,
201 gNextAddress = gAddressBase;
207 return (void*)gNextAddress;
222 INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */
223 INTERNAL_SIZE_T size; /* Size in bytes, including overhead. */
224 struct malloc_chunk* fd; /* double links -- used only if free. */
225 struct malloc_chunk* bk;
226 } __attribute__((__may_alias__)) ;
228 typedef struct malloc_chunk* mchunkptr;
232 malloc_chunk details:
234 (The following includes lightly edited explanations by Colin Plumb.)
236 Chunks of memory are maintained using a `boundary tag' method as
237 described in e.g., Knuth or Standish. (See the paper by Paul
238 Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
239 survey of such techniques.) Sizes of free chunks are stored both
240 in the front of each chunk and at the end. This makes
241 consolidating fragmented chunks into bigger chunks very fast. The
242 size fields also hold bits representing whether chunks are free or
245 An allocated chunk looks like this:
248 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
249 | Size of previous chunk, if allocated | |
250 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
251 | Size of chunk, in bytes |P|
252 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
253 | User data starts here... .
255 . (malloc_usable_space() bytes) .
257 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
259 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
262 Where "chunk" is the front of the chunk for the purpose of most of
263 the malloc code, but "mem" is the pointer that is returned to the
264 user. "Nextchunk" is the beginning of the next contiguous chunk.
266 Chunks always begin on even word boundries, so the mem portion
267 (which is returned to the user) is also on an even word boundary, and
268 thus double-word aligned.
270 Free chunks are stored in circular doubly-linked lists, and look like this:
272 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
273 | Size of previous chunk |
274 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
275 `head:' | Size of chunk, in bytes |P|
276 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
277 | Forward pointer to next chunk in list |
278 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
279 | Back pointer to previous chunk in list |
280 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
281 | Unused space (may be 0 bytes long) .
285 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
286 `foot:' | Size of chunk, in bytes |
287 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
289 The P (PREV_INUSE) bit, stored in the unused low-order bit of the
290 chunk size (which is always a multiple of two words), is an in-use
291 bit for the *previous* chunk. If that bit is *clear*, then the
292 word before the current chunk size contains the previous chunk
293 size, and can be used to find the front of the previous chunk.
294 (The very first chunk allocated always has this bit set,
295 preventing access to non-existent (or non-owned) memory.)
297 Note that the `foot' of the current chunk is actually represented
298 as the prev_size of the NEXT chunk. (This makes it easier to
299 deal with alignments etc).
301 The two exceptions to all this are
303 1. The special chunk `top', which doesn't bother using the
304 trailing size field since there is no
305 next contiguous chunk that would have to index off it. (After
306 initialization, `top' is forced to always exist. If it would
307 become less than MINSIZE bytes long, it is replenished via
310 2. Chunks allocated via mmap, which have the second-lowest-order
311 bit (IS_MMAPPED) set in their size fields. Because they are
312 never merged or traversed from any other chunk, they have no
313 foot size or inuse information.
315 Available chunks are kept in any of several places (all declared below):
317 * `av': An array of chunks serving as bin headers for consolidated
318 chunks. Each bin is doubly linked. The bins are approximately
319 proportionally (log) spaced. There are a lot of these bins
320 (128). This may look excessive, but works very well in
321 practice. All procedures maintain the invariant that no
322 consolidated chunk physically borders another one. Chunks in
323 bins are kept in size order, with ties going to the
324 approximately least recently used chunk.
326 The chunks in each bin are maintained in decreasing sorted order by
327 size. This is irrelevant for the small bins, which all contain
328 the same-sized chunks, but facilitates best-fit allocation for
329 larger chunks. (These lists are just sequential. Keeping them in
330 order almost never requires enough traversal to warrant using
331 fancier ordered data structures.) Chunks of the same size are
332 linked with the most recently freed at the front, and allocations
333 are taken from the back. This results in LRU or FIFO allocation
334 order, which tends to give each chunk an equal opportunity to be
335 consolidated with adjacent freed chunks, resulting in larger free
336 chunks and less fragmentation.
338 * `top': The top-most available chunk (i.e., the one bordering the
339 end of available memory) is treated specially. It is never
340 included in any bin, is used only if no other chunk is
341 available, and is released back to the system if it is very
342 large (see M_TRIM_THRESHOLD).
344 * `last_remainder': A bin holding only the remainder of the
345 most recently split (non-top) chunk. This bin is checked
346 before other non-fitting chunks, so as to provide better
347 locality for runs of sequentially allocated chunks.
349 * Implicitly, through the host system's memory mapping tables.
350 If supported, requests greater than a threshold are usually
351 serviced via calls to mmap, and then later released via munmap.
355 /* sizes, alignments */
357 #define SIZE_SZ (sizeof(INTERNAL_SIZE_T))
358 #define MALLOC_ALIGNMENT (SIZE_SZ + SIZE_SZ)
359 #define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)
360 #define MINSIZE (sizeof(struct malloc_chunk))
362 /* conversion from malloc headers to user pointers, and back */
364 #define chunk2mem(p) ((Void_t*)((char*)(p) + 2*SIZE_SZ))
365 #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))
367 /* pad request bytes into a usable size */
369 #define request2size(req) \
370 (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
371 (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
372 (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))
374 /* Check if m has acceptable alignment */
376 #define aligned_OK(m) (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)
382 Physical chunk operations
386 /* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */
388 #define PREV_INUSE 0x1
390 /* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */
392 #define IS_MMAPPED 0x2
394 /* Bits to mask off when extracting size */
396 #define SIZE_BITS (PREV_INUSE|IS_MMAPPED)
399 /* Ptr to next physical malloc_chunk. */
401 #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) ))
403 /* Ptr to previous physical malloc_chunk */
405 #define prev_chunk(p)\
406 ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))
409 /* Treat space at ptr + offset as a chunk */
411 #define chunk_at_offset(p, s) ((mchunkptr)(((char*)(p)) + (s)))
417 Dealing with use bits
420 /* extract p's inuse bit */
423 ((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)
425 /* extract inuse bit of previous chunk */
427 #define prev_inuse(p) ((p)->size & PREV_INUSE)
429 /* check for mmap()'ed chunk */
431 #define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)
433 /* set/clear chunk as in use without otherwise disturbing */
435 #define set_inuse(p)\
436 ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE
438 #define clear_inuse(p)\
439 ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)
441 /* check/set/clear inuse bits in known places */
443 #define inuse_bit_at_offset(p, s)\
444 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)
446 #define set_inuse_bit_at_offset(p, s)\
447 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)
449 #define clear_inuse_bit_at_offset(p, s)\
450 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))
456 Dealing with size fields
459 /* Get size, ignoring use bits */
461 #define chunksize(p) ((p)->size & ~(SIZE_BITS))
463 /* Set size at head, without disturbing its use bit */
465 #define set_head_size(p, s) ((p)->size = (((p)->size & PREV_INUSE) | (s)))
467 /* Set size/use ignoring previous bits in header */
469 #define set_head(p, s) ((p)->size = (s))
471 /* Set size at footer (only when chunk is not in use) */
473 #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))
482 The bins, `av_' are an array of pairs of pointers serving as the
483 heads of (initially empty) doubly-linked lists of chunks, laid out
484 in a way so that each pair can be treated as if it were in a
485 malloc_chunk. (This way, the fd/bk offsets for linking bin heads
486 and chunks are the same).
488 Bins for sizes < 512 bytes contain chunks of all the same size, spaced
489 8 bytes apart. Larger bins are approximately logarithmically
490 spaced. (See the table below.) The `av_' array is never mentioned
491 directly in the code, but instead via bin access macros.
500 2 bins of size 262144
501 1 bin of size what's left
503 There is actually a little bit of slop in the numbers in bin_index
504 for the sake of speed. This makes no difference elsewhere.
506 The special chunks `top' and `last_remainder' get their own bins,
507 (this is implemented via yet more trickery with the av_ array),
508 although `top' is never properly linked to its bin since it is
509 always handled specially.
513 #define NAV 128 /* number of bins */
515 typedef struct malloc_chunk* mbinptr;
519 #define bin_at(i) ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ))
520 #define next_bin(b) ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr)))
521 #define prev_bin(b) ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr)))
524 The first 2 bins are never indexed. The corresponding av_ cells are instead
525 used for bookkeeping. This is not to save space, but to simplify
526 indexing, maintain locality, and avoid some initialization tests.
529 #define top (av_[2]) /* The topmost chunk */
530 #define last_remainder (bin_at(1)) /* remainder from last split */
534 Because top initially points to its own bin with initial
535 zero size, thus forcing extension on the first malloc request,
536 we avoid having any special code in malloc to check whether
537 it even exists yet. But we still need to in malloc_extend_top.
540 #define initial_top ((mchunkptr)(bin_at(0)))
542 /* Helper macro to initialize bins */
544 #define IAV(i) bin_at(i), bin_at(i)
546 static mbinptr av_[NAV * 2 + 2] = {
548 IAV(0), IAV(1), IAV(2), IAV(3), IAV(4), IAV(5), IAV(6), IAV(7),
549 IAV(8), IAV(9), IAV(10), IAV(11), IAV(12), IAV(13), IAV(14), IAV(15),
550 IAV(16), IAV(17), IAV(18), IAV(19), IAV(20), IAV(21), IAV(22), IAV(23),
551 IAV(24), IAV(25), IAV(26), IAV(27), IAV(28), IAV(29), IAV(30), IAV(31),
552 IAV(32), IAV(33), IAV(34), IAV(35), IAV(36), IAV(37), IAV(38), IAV(39),
553 IAV(40), IAV(41), IAV(42), IAV(43), IAV(44), IAV(45), IAV(46), IAV(47),
554 IAV(48), IAV(49), IAV(50), IAV(51), IAV(52), IAV(53), IAV(54), IAV(55),
555 IAV(56), IAV(57), IAV(58), IAV(59), IAV(60), IAV(61), IAV(62), IAV(63),
556 IAV(64), IAV(65), IAV(66), IAV(67), IAV(68), IAV(69), IAV(70), IAV(71),
557 IAV(72), IAV(73), IAV(74), IAV(75), IAV(76), IAV(77), IAV(78), IAV(79),
558 IAV(80), IAV(81), IAV(82), IAV(83), IAV(84), IAV(85), IAV(86), IAV(87),
559 IAV(88), IAV(89), IAV(90), IAV(91), IAV(92), IAV(93), IAV(94), IAV(95),
560 IAV(96), IAV(97), IAV(98), IAV(99), IAV(100), IAV(101), IAV(102), IAV(103),
561 IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111),
562 IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119),
563 IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127)
566 #ifdef CONFIG_NEEDS_MANUAL_RELOC
567 static void malloc_bin_reloc(void)
569 mbinptr *p = &av_[2];
572 for (i = 2; i < ARRAY_SIZE(av_); ++i, ++p)
573 *p = (mbinptr)((ulong)*p + gd->reloc_off);
576 static inline void malloc_bin_reloc(void) {}
579 #ifdef CONFIG_SYS_MALLOC_DEFAULT_TO_INIT
580 static void malloc_init(void);
583 ulong mem_malloc_start = 0;
584 ulong mem_malloc_end = 0;
585 ulong mem_malloc_brk = 0;
587 void *sbrk(ptrdiff_t increment)
589 ulong old = mem_malloc_brk;
590 ulong new = old + increment;
593 * if we are giving memory back make sure we clear it out since
594 * we set MORECORE_CLEARS to 1
597 memset((void *)new, 0, -increment);
599 if ((new < mem_malloc_start) || (new > mem_malloc_end))
600 return (void *)MORECORE_FAILURE;
602 mem_malloc_brk = new;
607 void mem_malloc_init(ulong start, ulong size)
609 mem_malloc_start = start;
610 mem_malloc_end = start + size;
611 mem_malloc_brk = start;
613 #ifdef CONFIG_SYS_MALLOC_DEFAULT_TO_INIT
617 debug("using memory %#lx-%#lx for malloc()\n", mem_malloc_start,
619 #ifdef CONFIG_SYS_MALLOC_CLEAR_ON_INIT
620 memset((void *)mem_malloc_start, 0x0, size);
625 /* field-extraction macros */
627 #define first(b) ((b)->fd)
628 #define last(b) ((b)->bk)
634 #define bin_index(sz) \
635 (((((unsigned long)(sz)) >> 9) == 0) ? (((unsigned long)(sz)) >> 3): \
636 ((((unsigned long)(sz)) >> 9) <= 4) ? 56 + (((unsigned long)(sz)) >> 6): \
637 ((((unsigned long)(sz)) >> 9) <= 20) ? 91 + (((unsigned long)(sz)) >> 9): \
638 ((((unsigned long)(sz)) >> 9) <= 84) ? 110 + (((unsigned long)(sz)) >> 12): \
639 ((((unsigned long)(sz)) >> 9) <= 340) ? 119 + (((unsigned long)(sz)) >> 15): \
640 ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \
643 bins for chunks < 512 are all spaced 8 bytes apart, and hold
644 identically sized chunks. This is exploited in malloc.
647 #define MAX_SMALLBIN 63
648 #define MAX_SMALLBIN_SIZE 512
649 #define SMALLBIN_WIDTH 8
651 #define smallbin_index(sz) (((unsigned long)(sz)) >> 3)
654 Requests are `small' if both the corresponding and the next bin are small
657 #define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH)
662 To help compensate for the large number of bins, a one-level index
663 structure is used for bin-by-bin searching. `binblocks' is a
664 one-word bitvector recording whether groups of BINBLOCKWIDTH bins
665 have any (possibly) non-empty bins, so they can be skipped over
666 all at once during during traversals. The bits are NOT always
667 cleared as soon as all bins in a block are empty, but instead only
668 when all are noticed to be empty during traversal in malloc.
671 #define BINBLOCKWIDTH 4 /* bins per block */
673 #define binblocks_r ((INTERNAL_SIZE_T)av_[1]) /* bitvector of nonempty blocks */
674 #define binblocks_w (av_[1])
676 /* bin<->block macros */
678 #define idx2binblock(ix) ((unsigned)1 << (ix / BINBLOCKWIDTH))
679 #define mark_binblock(ii) (binblocks_w = (mbinptr)(binblocks_r | idx2binblock(ii)))
680 #define clear_binblock(ii) (binblocks_w = (mbinptr)(binblocks_r & ~(idx2binblock(ii))))
686 /* Other static bookkeeping data */
688 /* variables holding tunable values */
690 static unsigned long trim_threshold = DEFAULT_TRIM_THRESHOLD;
691 static unsigned long top_pad = DEFAULT_TOP_PAD;
692 static unsigned int n_mmaps_max = DEFAULT_MMAP_MAX;
693 static unsigned long mmap_threshold = DEFAULT_MMAP_THRESHOLD;
695 /* The first value returned from sbrk */
696 static char* sbrk_base = (char*)(-1);
698 /* The maximum memory obtained from system via sbrk */
699 static unsigned long max_sbrked_mem = 0;
701 /* The maximum via either sbrk or mmap */
702 static unsigned long max_total_mem = 0;
704 /* internal working copy of mallinfo */
705 static struct mallinfo current_mallinfo = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
707 /* The total memory obtained from system via sbrk */
708 #define sbrked_mem (current_mallinfo.arena)
713 static unsigned int n_mmaps = 0;
715 static unsigned long mmapped_mem = 0;
717 static unsigned int max_n_mmaps = 0;
718 static unsigned long max_mmapped_mem = 0;
721 #ifdef CONFIG_SYS_MALLOC_DEFAULT_TO_INIT
722 static void malloc_init(void)
726 debug("bins (av_ array) are at %p\n", (void *)av_);
728 av_[0] = NULL; av_[1] = NULL;
729 for (i = 2, j = 2; i < NAV * 2 + 2; i += 2, j++) {
730 av_[i] = bin_at(j - 2);
731 av_[i + 1] = bin_at(j - 2);
733 /* Just print the first few bins so that
734 * we can see there are alright.
737 debug("av_[%d]=%lx av_[%d]=%lx\n",
739 i + 1, (ulong)av_[i + 1]);
742 /* Init the static bookkeeping as well */
743 sbrk_base = (char *)(-1);
747 memset((void *)¤t_mallinfo, 0, sizeof(struct mallinfo));
760 These routines make a number of assertions about the states
761 of data structures that should be true at all times. If any
762 are not true, it's very likely that a user program has somehow
763 trashed memory. (It's also possible that there is a coding error
764 in malloc. In which case, please report it!)
768 static void do_check_chunk(mchunkptr p)
770 static void do_check_chunk(p) mchunkptr p;
773 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
775 /* No checkable chunk is mmapped */
776 assert(!chunk_is_mmapped(p));
778 /* Check for legal address ... */
779 assert((char*)p >= sbrk_base);
781 assert((char*)p + sz <= (char*)top);
783 assert((char*)p + sz <= sbrk_base + sbrked_mem);
789 static void do_check_free_chunk(mchunkptr p)
791 static void do_check_free_chunk(p) mchunkptr p;
794 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
795 mchunkptr next = chunk_at_offset(p, sz);
799 /* Check whether it claims to be free ... */
802 /* Unless a special marker, must have OK fields */
803 if ((long)sz >= (long)MINSIZE)
805 assert((sz & MALLOC_ALIGN_MASK) == 0);
806 assert(aligned_OK(chunk2mem(p)));
807 /* ... matching footer field */
808 assert(next->prev_size == sz);
809 /* ... and is fully consolidated */
810 assert(prev_inuse(p));
811 assert (next == top || inuse(next));
813 /* ... and has minimally sane links */
814 assert(p->fd->bk == p);
815 assert(p->bk->fd == p);
817 else /* markers are always of size SIZE_SZ */
818 assert(sz == SIZE_SZ);
822 static void do_check_inuse_chunk(mchunkptr p)
824 static void do_check_inuse_chunk(p) mchunkptr p;
827 mchunkptr next = next_chunk(p);
830 /* Check whether it claims to be in use ... */
833 /* ... and is surrounded by OK chunks.
834 Since more things can be checked with free chunks than inuse ones,
835 if an inuse chunk borders them and debug is on, it's worth doing them.
839 mchunkptr prv = prev_chunk(p);
840 assert(next_chunk(prv) == p);
841 do_check_free_chunk(prv);
845 assert(prev_inuse(next));
846 assert(chunksize(next) >= MINSIZE);
848 else if (!inuse(next))
849 do_check_free_chunk(next);
854 static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s)
856 static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s;
859 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
862 do_check_inuse_chunk(p);
865 assert((long)sz >= (long)MINSIZE);
866 assert((sz & MALLOC_ALIGN_MASK) == 0);
868 assert(room < (long)MINSIZE);
870 /* ... and alignment */
871 assert(aligned_OK(chunk2mem(p)));
874 /* ... and was allocated at front of an available chunk */
875 assert(prev_inuse(p));
880 #define check_free_chunk(P) do_check_free_chunk(P)
881 #define check_inuse_chunk(P) do_check_inuse_chunk(P)
882 #define check_chunk(P) do_check_chunk(P)
883 #define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N)
885 #define check_free_chunk(P)
886 #define check_inuse_chunk(P)
887 #define check_chunk(P)
888 #define check_malloced_chunk(P,N)
894 Macro-based internal utilities
899 Linking chunks in bin lists.
900 Call these only with variables, not arbitrary expressions, as arguments.
904 Place chunk p of size s in its bin, in size order,
905 putting it ahead of others of same size.
909 #define frontlink(P, S, IDX, BK, FD) \
911 if (S < MAX_SMALLBIN_SIZE) \
913 IDX = smallbin_index(S); \
914 mark_binblock(IDX); \
919 FD->bk = BK->fd = P; \
923 IDX = bin_index(S); \
926 if (FD == BK) mark_binblock(IDX); \
929 while (FD != BK && S < chunksize(FD)) FD = FD->fd; \
934 FD->bk = BK->fd = P; \
939 /* take a chunk off a list */
941 #define unlink(P, BK, FD) \
949 /* Place p as the last remainder */
951 #define link_last_remainder(P) \
953 last_remainder->fd = last_remainder->bk = P; \
954 P->fd = P->bk = last_remainder; \
957 /* Clear the last_remainder bin */
959 #define clear_last_remainder \
960 (last_remainder->fd = last_remainder->bk = last_remainder)
966 /* Routines dealing with mmap(). */
971 static mchunkptr mmap_chunk(size_t size)
973 static mchunkptr mmap_chunk(size) size_t size;
976 size_t page_mask = malloc_getpagesize - 1;
979 #ifndef MAP_ANONYMOUS
983 if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */
985 /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because
986 * there is no following chunk whose prev_size field could be used.
988 size = (size + SIZE_SZ + page_mask) & ~page_mask;
991 p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE,
992 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
993 #else /* !MAP_ANONYMOUS */
996 fd = open("/dev/zero", O_RDWR);
999 p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
1002 if(p == (mchunkptr)-1) return 0;
1005 if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps;
1007 /* We demand that eight bytes into a page must be 8-byte aligned. */
1008 assert(aligned_OK(chunk2mem(p)));
1010 /* The offset to the start of the mmapped region is stored
1011 * in the prev_size field of the chunk; normally it is zero,
1012 * but that can be changed in memalign().
1015 set_head(p, size|IS_MMAPPED);
1017 mmapped_mem += size;
1018 if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1019 max_mmapped_mem = mmapped_mem;
1020 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1021 max_total_mem = mmapped_mem + sbrked_mem;
1026 static void munmap_chunk(mchunkptr p)
1028 static void munmap_chunk(p) mchunkptr p;
1031 INTERNAL_SIZE_T size = chunksize(p);
1034 assert (chunk_is_mmapped(p));
1035 assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1036 assert((n_mmaps > 0));
1037 assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0);
1040 mmapped_mem -= (size + p->prev_size);
1042 ret = munmap((char *)p - p->prev_size, size + p->prev_size);
1044 /* munmap returns non-zero on failure */
1051 static mchunkptr mremap_chunk(mchunkptr p, size_t new_size)
1053 static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size;
1056 size_t page_mask = malloc_getpagesize - 1;
1057 INTERNAL_SIZE_T offset = p->prev_size;
1058 INTERNAL_SIZE_T size = chunksize(p);
1061 assert (chunk_is_mmapped(p));
1062 assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1063 assert((n_mmaps > 0));
1064 assert(((size + offset) & (malloc_getpagesize-1)) == 0);
1066 /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
1067 new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask;
1069 cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1);
1071 if (cp == (char *)-1) return 0;
1073 p = (mchunkptr)(cp + offset);
1075 assert(aligned_OK(chunk2mem(p)));
1077 assert((p->prev_size == offset));
1078 set_head(p, (new_size - offset)|IS_MMAPPED);
1080 mmapped_mem -= size + offset;
1081 mmapped_mem += new_size;
1082 if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1083 max_mmapped_mem = mmapped_mem;
1084 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1085 max_total_mem = mmapped_mem + sbrked_mem;
1089 #endif /* HAVE_MREMAP */
1091 #endif /* HAVE_MMAP */
1094 Extend the top-most chunk by obtaining memory from system.
1095 Main interface to sbrk (but see also malloc_trim).
1099 static void malloc_extend_top(INTERNAL_SIZE_T nb)
1101 static void malloc_extend_top(nb) INTERNAL_SIZE_T nb;
1104 char* brk; /* return value from sbrk */
1105 INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */
1106 INTERNAL_SIZE_T correction; /* bytes for 2nd sbrk call */
1107 char* new_brk; /* return of 2nd sbrk call */
1108 INTERNAL_SIZE_T top_size; /* new size of top chunk */
1110 mchunkptr old_top = top; /* Record state of old top */
1111 INTERNAL_SIZE_T old_top_size = chunksize(old_top);
1112 char* old_end = (char*)(chunk_at_offset(old_top, old_top_size));
1114 /* Pad request with top_pad plus minimal overhead */
1116 INTERNAL_SIZE_T sbrk_size = nb + top_pad + MINSIZE;
1117 unsigned long pagesz = malloc_getpagesize;
1119 /* If not the first time through, round to preserve page boundary */
1120 /* Otherwise, we need to correct to a page size below anyway. */
1121 /* (We also correct below if an intervening foreign sbrk call.) */
1123 if (sbrk_base != (char*)(-1))
1124 sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1);
1126 brk = (char*)(MORECORE (sbrk_size));
1128 /* Fail if sbrk failed or if a foreign sbrk call killed our space */
1129 if (brk == (char*)(MORECORE_FAILURE) ||
1130 (brk < old_end && old_top != initial_top))
1133 sbrked_mem += sbrk_size;
1135 if (brk == old_end) /* can just add bytes to current top */
1137 top_size = sbrk_size + old_top_size;
1138 set_head(top, top_size | PREV_INUSE);
1142 if (sbrk_base == (char*)(-1)) /* First time through. Record base */
1144 else /* Someone else called sbrk(). Count those bytes as sbrked_mem. */
1145 sbrked_mem += brk - (char*)old_end;
1147 /* Guarantee alignment of first new chunk made from this space */
1148 front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK;
1149 if (front_misalign > 0)
1151 correction = (MALLOC_ALIGNMENT) - front_misalign;
1157 /* Guarantee the next brk will be at a page boundary */
1159 correction += ((((unsigned long)(brk + sbrk_size))+(pagesz-1)) &
1160 ~(pagesz - 1)) - ((unsigned long)(brk + sbrk_size));
1162 /* Allocate correction */
1163 new_brk = (char*)(MORECORE (correction));
1164 if (new_brk == (char*)(MORECORE_FAILURE)) return;
1166 sbrked_mem += correction;
1168 top = (mchunkptr)brk;
1169 top_size = new_brk - brk + correction;
1170 set_head(top, top_size | PREV_INUSE);
1172 if (old_top != initial_top)
1175 /* There must have been an intervening foreign sbrk call. */
1176 /* A double fencepost is necessary to prevent consolidation */
1178 /* If not enough space to do this, then user did something very wrong */
1179 if (old_top_size < MINSIZE)
1181 set_head(top, PREV_INUSE); /* will force null return from malloc */
1185 /* Also keep size a multiple of MALLOC_ALIGNMENT */
1186 old_top_size = (old_top_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK;
1187 set_head_size(old_top, old_top_size);
1188 chunk_at_offset(old_top, old_top_size )->size =
1190 chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size =
1192 /* If possible, release the rest. */
1193 if (old_top_size >= MINSIZE)
1194 fREe(chunk2mem(old_top));
1198 if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem)
1199 max_sbrked_mem = sbrked_mem;
1200 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1201 max_total_mem = mmapped_mem + sbrked_mem;
1203 /* We always land on a page boundary */
1204 assert(((unsigned long)((char*)top + top_size) & (pagesz - 1)) == 0);
1210 /* Main public routines */
1216 The requested size is first converted into a usable form, `nb'.
1217 This currently means to add 4 bytes overhead plus possibly more to
1218 obtain 8-byte alignment and/or to obtain a size of at least
1219 MINSIZE (currently 16 bytes), the smallest allocatable size.
1220 (All fits are considered `exact' if they are within MINSIZE bytes.)
1222 From there, the first successful of the following steps is taken:
1224 1. The bin corresponding to the request size is scanned, and if
1225 a chunk of exactly the right size is found, it is taken.
1227 2. The most recently remaindered chunk is used if it is big
1228 enough. This is a form of (roving) first fit, used only in
1229 the absence of exact fits. Runs of consecutive requests use
1230 the remainder of the chunk used for the previous such request
1231 whenever possible. This limited use of a first-fit style
1232 allocation strategy tends to give contiguous chunks
1233 coextensive lifetimes, which improves locality and can reduce
1234 fragmentation in the long run.
1236 3. Other bins are scanned in increasing size order, using a
1237 chunk big enough to fulfill the request, and splitting off
1238 any remainder. This search is strictly by best-fit; i.e.,
1239 the smallest (with ties going to approximately the least
1240 recently used) chunk that fits is selected.
1242 4. If large enough, the chunk bordering the end of memory
1243 (`top') is split off. (This use of `top' is in accord with
1244 the best-fit search rule. In effect, `top' is treated as
1245 larger (and thus less well fitting) than any other available
1246 chunk since it can be extended to be as large as necessary
1247 (up to system limitations).
1249 5. If the request size meets the mmap threshold and the
1250 system supports mmap, and there are few enough currently
1251 allocated mmapped regions, and a call to mmap succeeds,
1252 the request is allocated via direct memory mapping.
1254 6. Otherwise, the top of memory is extended by
1255 obtaining more space from the system (normally using sbrk,
1256 but definable to anything else via the MORECORE macro).
1257 Memory is gathered from the system (in system page-sized
1258 units) in a way that allows chunks obtained across different
1259 sbrk calls to be consolidated, but does not require
1260 contiguous memory. Thus, it should be safe to intersperse
1261 mallocs with other sbrk calls.
1264 All allocations are made from the the `lowest' part of any found
1265 chunk. (The implementation invariant is that prev_inuse is
1266 always true of any allocated chunk; i.e., that each allocated
1267 chunk borders either a previously allocated and still in-use chunk,
1268 or the base of its memory arena.)
1273 Void_t* mALLOc(size_t bytes)
1275 Void_t* mALLOc(bytes) size_t bytes;
1278 mchunkptr victim; /* inspected/selected chunk */
1279 INTERNAL_SIZE_T victim_size; /* its size */
1280 int idx; /* index for bin traversal */
1281 mbinptr bin; /* associated bin */
1282 mchunkptr remainder; /* remainder from a split */
1283 long remainder_size; /* its size */
1284 int remainder_index; /* its bin index */
1285 unsigned long block; /* block traverser bit */
1286 int startidx; /* first bin of a traversed block */
1287 mchunkptr fwd; /* misc temp for linking */
1288 mchunkptr bck; /* misc temp for linking */
1289 mbinptr q; /* misc temp */
1293 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
1294 if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT))
1295 return malloc_simple(bytes);
1298 /* check if mem_malloc_init() was run */
1299 if ((mem_malloc_start == 0) && (mem_malloc_end == 0)) {
1300 /* not initialized yet */
1304 if ((long)bytes < 0) return NULL;
1306 nb = request2size(bytes); /* padded request size; */
1308 /* Check for exact match in a bin */
1310 if (is_small_request(nb)) /* Faster version for small requests */
1312 idx = smallbin_index(nb);
1314 /* No traversal or size check necessary for small bins. */
1319 /* Also scan the next one, since it would have a remainder < MINSIZE */
1327 victim_size = chunksize(victim);
1328 unlink(victim, bck, fwd);
1329 set_inuse_bit_at_offset(victim, victim_size);
1330 check_malloced_chunk(victim, nb);
1331 return chunk2mem(victim);
1334 idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */
1339 idx = bin_index(nb);
1342 for (victim = last(bin); victim != bin; victim = victim->bk)
1344 victim_size = chunksize(victim);
1345 remainder_size = victim_size - nb;
1347 if (remainder_size >= (long)MINSIZE) /* too big */
1349 --idx; /* adjust to rescan below after checking last remainder */
1353 else if (remainder_size >= 0) /* exact fit */
1355 unlink(victim, bck, fwd);
1356 set_inuse_bit_at_offset(victim, victim_size);
1357 check_malloced_chunk(victim, nb);
1358 return chunk2mem(victim);
1366 /* Try to use the last split-off remainder */
1368 if ( (victim = last_remainder->fd) != last_remainder)
1370 victim_size = chunksize(victim);
1371 remainder_size = victim_size - nb;
1373 if (remainder_size >= (long)MINSIZE) /* re-split */
1375 remainder = chunk_at_offset(victim, nb);
1376 set_head(victim, nb | PREV_INUSE);
1377 link_last_remainder(remainder);
1378 set_head(remainder, remainder_size | PREV_INUSE);
1379 set_foot(remainder, remainder_size);
1380 check_malloced_chunk(victim, nb);
1381 return chunk2mem(victim);
1384 clear_last_remainder;
1386 if (remainder_size >= 0) /* exhaust */
1388 set_inuse_bit_at_offset(victim, victim_size);
1389 check_malloced_chunk(victim, nb);
1390 return chunk2mem(victim);
1393 /* Else place in bin */
1395 frontlink(victim, victim_size, remainder_index, bck, fwd);
1399 If there are any possibly nonempty big-enough blocks,
1400 search for best fitting chunk by scanning bins in blockwidth units.
1403 if ( (block = idx2binblock(idx)) <= binblocks_r)
1406 /* Get to the first marked block */
1408 if ( (block & binblocks_r) == 0)
1410 /* force to an even block boundary */
1411 idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH;
1413 while ((block & binblocks_r) == 0)
1415 idx += BINBLOCKWIDTH;
1420 /* For each possibly nonempty block ... */
1423 startidx = idx; /* (track incomplete blocks) */
1424 q = bin = bin_at(idx);
1426 /* For each bin in this block ... */
1429 /* Find and use first big enough chunk ... */
1431 for (victim = last(bin); victim != bin; victim = victim->bk)
1433 victim_size = chunksize(victim);
1434 remainder_size = victim_size - nb;
1436 if (remainder_size >= (long)MINSIZE) /* split */
1438 remainder = chunk_at_offset(victim, nb);
1439 set_head(victim, nb | PREV_INUSE);
1440 unlink(victim, bck, fwd);
1441 link_last_remainder(remainder);
1442 set_head(remainder, remainder_size | PREV_INUSE);
1443 set_foot(remainder, remainder_size);
1444 check_malloced_chunk(victim, nb);
1445 return chunk2mem(victim);
1448 else if (remainder_size >= 0) /* take */
1450 set_inuse_bit_at_offset(victim, victim_size);
1451 unlink(victim, bck, fwd);
1452 check_malloced_chunk(victim, nb);
1453 return chunk2mem(victim);
1458 bin = next_bin(bin);
1460 } while ((++idx & (BINBLOCKWIDTH - 1)) != 0);
1462 /* Clear out the block bit. */
1464 do /* Possibly backtrack to try to clear a partial block */
1466 if ((startidx & (BINBLOCKWIDTH - 1)) == 0)
1468 av_[1] = (mbinptr)(binblocks_r & ~block);
1473 } while (first(q) == q);
1475 /* Get to the next possibly nonempty block */
1477 if ( (block <<= 1) <= binblocks_r && (block != 0) )
1479 while ((block & binblocks_r) == 0)
1481 idx += BINBLOCKWIDTH;
1491 /* Try to use top chunk */
1493 /* Require that there be a remainder, ensuring top always exists */
1494 if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
1498 /* If big and would otherwise need to extend, try to use mmap instead */
1499 if ((unsigned long)nb >= (unsigned long)mmap_threshold &&
1500 (victim = mmap_chunk(nb)))
1501 return chunk2mem(victim);
1505 malloc_extend_top(nb);
1506 if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
1507 return NULL; /* propagate failure */
1511 set_head(victim, nb | PREV_INUSE);
1512 top = chunk_at_offset(victim, nb);
1513 set_head(top, remainder_size | PREV_INUSE);
1514 check_malloced_chunk(victim, nb);
1515 return chunk2mem(victim);
1528 1. free(0) has no effect.
1530 2. If the chunk was allocated via mmap, it is release via munmap().
1532 3. If a returned chunk borders the current high end of memory,
1533 it is consolidated into the top, and if the total unused
1534 topmost memory exceeds the trim threshold, malloc_trim is
1537 4. Other chunks are consolidated as they arrive, and
1538 placed in corresponding bins. (This includes the case of
1539 consolidating with the current `last_remainder').
1545 void fREe(Void_t* mem)
1547 void fREe(mem) Void_t* mem;
1550 mchunkptr p; /* chunk corresponding to mem */
1551 INTERNAL_SIZE_T hd; /* its head field */
1552 INTERNAL_SIZE_T sz; /* its size */
1553 int idx; /* its bin index */
1554 mchunkptr next; /* next contiguous chunk */
1555 INTERNAL_SIZE_T nextsz; /* its size */
1556 INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */
1557 mchunkptr bck; /* misc temp for linking */
1558 mchunkptr fwd; /* misc temp for linking */
1559 int islr; /* track whether merging with last_remainder */
1561 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
1562 /* free() is a no-op - all the memory will be freed on relocation */
1563 if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT))
1567 if (mem == NULL) /* free(0) has no effect */
1574 if (hd & IS_MMAPPED) /* release mmapped memory. */
1581 check_inuse_chunk(p);
1583 sz = hd & ~PREV_INUSE;
1584 next = chunk_at_offset(p, sz);
1585 nextsz = chunksize(next);
1587 if (next == top) /* merge with top */
1591 if (!(hd & PREV_INUSE)) /* consolidate backward */
1593 prevsz = p->prev_size;
1594 p = chunk_at_offset(p, -((long) prevsz));
1596 unlink(p, bck, fwd);
1599 set_head(p, sz | PREV_INUSE);
1601 if ((unsigned long)(sz) >= (unsigned long)trim_threshold)
1602 malloc_trim(top_pad);
1606 set_head(next, nextsz); /* clear inuse bit */
1610 if (!(hd & PREV_INUSE)) /* consolidate backward */
1612 prevsz = p->prev_size;
1613 p = chunk_at_offset(p, -((long) prevsz));
1616 if (p->fd == last_remainder) /* keep as last_remainder */
1619 unlink(p, bck, fwd);
1622 if (!(inuse_bit_at_offset(next, nextsz))) /* consolidate forward */
1626 if (!islr && next->fd == last_remainder) /* re-insert last_remainder */
1629 link_last_remainder(p);
1632 unlink(next, bck, fwd);
1636 set_head(p, sz | PREV_INUSE);
1639 frontlink(p, sz, idx, bck, fwd);
1650 Chunks that were obtained via mmap cannot be extended or shrunk
1651 unless HAVE_MREMAP is defined, in which case mremap is used.
1652 Otherwise, if their reallocation is for additional space, they are
1653 copied. If for less, they are just left alone.
1655 Otherwise, if the reallocation is for additional space, and the
1656 chunk can be extended, it is, else a malloc-copy-free sequence is
1657 taken. There are several different ways that a chunk could be
1658 extended. All are tried:
1660 * Extending forward into following adjacent free chunk.
1661 * Shifting backwards, joining preceding adjacent space
1662 * Both shifting backwards and extending forward.
1663 * Extending into newly sbrked space
1665 Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a
1666 size argument of zero (re)allocates a minimum-sized chunk.
1668 If the reallocation is for less space, and the new request is for
1669 a `small' (<512 bytes) size, then the newly unused space is lopped
1672 The old unix realloc convention of allowing the last-free'd chunk
1673 to be used as an argument to realloc is no longer supported.
1674 I don't know of any programs still relying on this feature,
1675 and allowing it would also allow too many other incorrect
1676 usages of realloc to be sensible.
1683 Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
1685 Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
1688 INTERNAL_SIZE_T nb; /* padded request size */
1690 mchunkptr oldp; /* chunk corresponding to oldmem */
1691 INTERNAL_SIZE_T oldsize; /* its size */
1693 mchunkptr newp; /* chunk to return */
1694 INTERNAL_SIZE_T newsize; /* its size */
1695 Void_t* newmem; /* corresponding user mem */
1697 mchunkptr next; /* next contiguous chunk after oldp */
1698 INTERNAL_SIZE_T nextsize; /* its size */
1700 mchunkptr prev; /* previous contiguous chunk before oldp */
1701 INTERNAL_SIZE_T prevsize; /* its size */
1703 mchunkptr remainder; /* holds split off extra space from newp */
1704 INTERNAL_SIZE_T remainder_size; /* its size */
1706 mchunkptr bck; /* misc temp for linking */
1707 mchunkptr fwd; /* misc temp for linking */
1709 #ifdef REALLOC_ZERO_BYTES_FREES
1716 if ((long)bytes < 0) return NULL;
1718 /* realloc of null is supposed to be same as malloc */
1719 if (oldmem == NULL) return mALLOc(bytes);
1721 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
1722 if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT)) {
1723 /* This is harder to support and should not be needed */
1724 panic("pre-reloc realloc() is not supported");
1728 newp = oldp = mem2chunk(oldmem);
1729 newsize = oldsize = chunksize(oldp);
1732 nb = request2size(bytes);
1735 if (chunk_is_mmapped(oldp))
1738 newp = mremap_chunk(oldp, nb);
1739 if(newp) return chunk2mem(newp);
1741 /* Note the extra SIZE_SZ overhead. */
1742 if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */
1743 /* Must alloc, copy, free. */
1744 newmem = mALLOc(bytes);
1746 return NULL; /* propagate failure */
1747 MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ);
1753 check_inuse_chunk(oldp);
1755 if ((long)(oldsize) < (long)(nb))
1758 /* Try expanding forward */
1760 next = chunk_at_offset(oldp, oldsize);
1761 if (next == top || !inuse(next))
1763 nextsize = chunksize(next);
1765 /* Forward into top only if a remainder */
1768 if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE))
1770 newsize += nextsize;
1771 top = chunk_at_offset(oldp, nb);
1772 set_head(top, (newsize - nb) | PREV_INUSE);
1773 set_head_size(oldp, nb);
1774 return chunk2mem(oldp);
1778 /* Forward into next chunk */
1779 else if (((long)(nextsize + newsize) >= (long)(nb)))
1781 unlink(next, bck, fwd);
1782 newsize += nextsize;
1792 /* Try shifting backwards. */
1794 if (!prev_inuse(oldp))
1796 prev = prev_chunk(oldp);
1797 prevsize = chunksize(prev);
1799 /* try forward + backward first to save a later consolidation */
1806 if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE))
1808 unlink(prev, bck, fwd);
1810 newsize += prevsize + nextsize;
1811 newmem = chunk2mem(newp);
1812 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
1813 top = chunk_at_offset(newp, nb);
1814 set_head(top, (newsize - nb) | PREV_INUSE);
1815 set_head_size(newp, nb);
1820 /* into next chunk */
1821 else if (((long)(nextsize + prevsize + newsize) >= (long)(nb)))
1823 unlink(next, bck, fwd);
1824 unlink(prev, bck, fwd);
1826 newsize += nextsize + prevsize;
1827 newmem = chunk2mem(newp);
1828 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
1834 if (prev != NULL && (long)(prevsize + newsize) >= (long)nb)
1836 unlink(prev, bck, fwd);
1838 newsize += prevsize;
1839 newmem = chunk2mem(newp);
1840 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
1847 newmem = mALLOc (bytes);
1849 if (newmem == NULL) /* propagate failure */
1852 /* Avoid copy if newp is next chunk after oldp. */
1853 /* (This can only happen when new chunk is sbrk'ed.) */
1855 if ( (newp = mem2chunk(newmem)) == next_chunk(oldp))
1857 newsize += chunksize(newp);
1862 /* Otherwise copy, free, and exit */
1863 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
1869 split: /* split off extra room in old or expanded chunk */
1871 if (newsize - nb >= MINSIZE) /* split off remainder */
1873 remainder = chunk_at_offset(newp, nb);
1874 remainder_size = newsize - nb;
1875 set_head_size(newp, nb);
1876 set_head(remainder, remainder_size | PREV_INUSE);
1877 set_inuse_bit_at_offset(remainder, remainder_size);
1878 fREe(chunk2mem(remainder)); /* let free() deal with it */
1882 set_head_size(newp, newsize);
1883 set_inuse_bit_at_offset(newp, newsize);
1886 check_inuse_chunk(newp);
1887 return chunk2mem(newp);
1897 memalign requests more than enough space from malloc, finds a spot
1898 within that chunk that meets the alignment request, and then
1899 possibly frees the leading and trailing space.
1901 The alignment argument must be a power of two. This property is not
1902 checked by memalign, so misuse may result in random runtime errors.
1904 8-byte alignment is guaranteed by normal malloc calls, so don't
1905 bother calling memalign with an argument of 8 or less.
1907 Overreliance on memalign is a sure way to fragment space.
1913 Void_t* mEMALIGn(size_t alignment, size_t bytes)
1915 Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
1918 INTERNAL_SIZE_T nb; /* padded request size */
1919 char* m; /* memory returned by malloc call */
1920 mchunkptr p; /* corresponding chunk */
1921 char* brk; /* alignment point within p */
1922 mchunkptr newp; /* chunk to return */
1923 INTERNAL_SIZE_T newsize; /* its size */
1924 INTERNAL_SIZE_T leadsize; /* leading space befor alignment point */
1925 mchunkptr remainder; /* spare room at end to split off */
1926 long remainder_size; /* its size */
1928 if ((long)bytes < 0) return NULL;
1930 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
1931 if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT)) {
1932 return memalign_simple(alignment, bytes);
1936 /* If need less alignment than we give anyway, just relay to malloc */
1938 if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes);
1940 /* Otherwise, ensure that it is at least a minimum chunk size */
1942 if (alignment < MINSIZE) alignment = MINSIZE;
1944 /* Call malloc with worst case padding to hit alignment. */
1946 nb = request2size(bytes);
1947 m = (char*)(mALLOc(nb + alignment + MINSIZE));
1950 * The attempt to over-allocate (with a size large enough to guarantee the
1951 * ability to find an aligned region within allocated memory) failed.
1953 * Try again, this time only allocating exactly the size the user wants. If
1954 * the allocation now succeeds and just happens to be aligned, we can still
1955 * fulfill the user's request.
1958 size_t extra, extra2;
1960 * Use bytes not nb, since mALLOc internally calls request2size too, and
1961 * each call increases the size to allocate, to account for the header.
1963 m = (char*)(mALLOc(bytes));
1964 /* Aligned -> return it */
1965 if ((((unsigned long)(m)) % alignment) == 0)
1968 * Otherwise, try again, requesting enough extra space to be able to
1969 * acquire alignment.
1972 /* Add in extra bytes to match misalignment of unexpanded allocation */
1973 extra = alignment - (((unsigned long)(m)) % alignment);
1974 m = (char*)(mALLOc(bytes + extra));
1976 * m might not be the same as before. Validate that the previous value of
1977 * extra still works for the current value of m.
1978 * If (!m), extra2=alignment so
1981 extra2 = alignment - (((unsigned long)(m)) % alignment);
1982 if (extra2 > extra) {
1987 /* Fall through to original NULL check and chunk splitting logic */
1990 if (m == NULL) return NULL; /* propagate failure */
1994 if ((((unsigned long)(m)) % alignment) == 0) /* aligned */
1997 if(chunk_is_mmapped(p))
1998 return chunk2mem(p); /* nothing more to do */
2001 else /* misaligned */
2004 Find an aligned spot inside chunk.
2005 Since we need to give back leading space in a chunk of at
2006 least MINSIZE, if the first calculation places us at
2007 a spot with less than MINSIZE leader, we can move to the
2008 next aligned spot -- we've allocated enough total room so that
2009 this is always possible.
2012 brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -((signed) alignment));
2013 if ((long)(brk - (char*)(p)) < MINSIZE) brk = brk + alignment;
2015 newp = (mchunkptr)brk;
2016 leadsize = brk - (char*)(p);
2017 newsize = chunksize(p) - leadsize;
2020 if(chunk_is_mmapped(p))
2022 newp->prev_size = p->prev_size + leadsize;
2023 set_head(newp, newsize|IS_MMAPPED);
2024 return chunk2mem(newp);
2028 /* give back leader, use the rest */
2030 set_head(newp, newsize | PREV_INUSE);
2031 set_inuse_bit_at_offset(newp, newsize);
2032 set_head_size(p, leadsize);
2036 assert (newsize >= nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0);
2039 /* Also give back spare room at the end */
2041 remainder_size = chunksize(p) - nb;
2043 if (remainder_size >= (long)MINSIZE)
2045 remainder = chunk_at_offset(p, nb);
2046 set_head(remainder, remainder_size | PREV_INUSE);
2047 set_head_size(p, nb);
2048 fREe(chunk2mem(remainder));
2051 check_inuse_chunk(p);
2052 return chunk2mem(p);
2060 valloc just invokes memalign with alignment argument equal
2061 to the page size of the system (or as near to this as can
2062 be figured out from all the includes/defines above.)
2066 Void_t* vALLOc(size_t bytes)
2068 Void_t* vALLOc(bytes) size_t bytes;
2071 return mEMALIGn (malloc_getpagesize, bytes);
2075 pvalloc just invokes valloc for the nearest pagesize
2076 that will accommodate request
2081 Void_t* pvALLOc(size_t bytes)
2083 Void_t* pvALLOc(bytes) size_t bytes;
2086 size_t pagesize = malloc_getpagesize;
2087 return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1));
2092 calloc calls malloc, then zeroes out the allocated chunk.
2097 Void_t* cALLOc(size_t n, size_t elem_size)
2099 Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size;
2103 INTERNAL_SIZE_T csz;
2105 INTERNAL_SIZE_T sz = n * elem_size;
2108 /* check if expand_top called, in which case don't need to clear */
2109 #ifdef CONFIG_SYS_MALLOC_CLEAR_ON_INIT
2111 mchunkptr oldtop = top;
2112 INTERNAL_SIZE_T oldtopsize = chunksize(top);
2115 Void_t* mem = mALLOc (sz);
2117 if ((long)n < 0) return NULL;
2123 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
2124 if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT)) {
2131 /* Two optional cases in which clearing not necessary */
2135 if (chunk_is_mmapped(p)) return mem;
2140 #ifdef CONFIG_SYS_MALLOC_CLEAR_ON_INIT
2142 if (p == oldtop && csz > oldtopsize)
2144 /* clear only the bytes from non-freshly-sbrked memory */
2150 MALLOC_ZERO(mem, csz - SIZE_SZ);
2157 cfree just calls free. It is needed/defined on some systems
2158 that pair it with calloc, presumably for odd historical reasons.
2162 #if !defined(INTERNAL_LINUX_C_LIB) || !defined(__ELF__)
2164 void cfree(Void_t *mem)
2166 void cfree(mem) Void_t *mem;
2177 Malloc_trim gives memory back to the system (via negative
2178 arguments to sbrk) if there is unused memory at the `high' end of
2179 the malloc pool. You can call this after freeing large blocks of
2180 memory to potentially reduce the system-level memory requirements
2181 of a program. However, it cannot guarantee to reduce memory. Under
2182 some allocation patterns, some large free blocks of memory will be
2183 locked between two used chunks, so they cannot be given back to
2186 The `pad' argument to malloc_trim represents the amount of free
2187 trailing space to leave untrimmed. If this argument is zero,
2188 only the minimum amount of memory to maintain internal data
2189 structures will be left (one page or less). Non-zero arguments
2190 can be supplied to maintain enough trailing space to service
2191 future expected allocations without having to re-obtain memory
2194 Malloc_trim returns 1 if it actually released any memory, else 0.
2199 int malloc_trim(size_t pad)
2201 int malloc_trim(pad) size_t pad;
2204 long top_size; /* Amount of top-most memory */
2205 long extra; /* Amount to release */
2206 char* current_brk; /* address returned by pre-check sbrk call */
2207 char* new_brk; /* address returned by negative sbrk call */
2209 unsigned long pagesz = malloc_getpagesize;
2211 top_size = chunksize(top);
2212 extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
2214 if (extra < (long)pagesz) /* Not enough memory to release */
2219 /* Test to make sure no one else called sbrk */
2220 current_brk = (char*)(MORECORE (0));
2221 if (current_brk != (char*)(top) + top_size)
2222 return 0; /* Apparently we don't own memory; must fail */
2226 new_brk = (char*)(MORECORE (-extra));
2228 if (new_brk == (char*)(MORECORE_FAILURE)) /* sbrk failed? */
2230 /* Try to figure out what we have */
2231 current_brk = (char*)(MORECORE (0));
2232 top_size = current_brk - (char*)top;
2233 if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */
2235 sbrked_mem = current_brk - sbrk_base;
2236 set_head(top, top_size | PREV_INUSE);
2244 /* Success. Adjust top accordingly. */
2245 set_head(top, (top_size - extra) | PREV_INUSE);
2246 sbrked_mem -= extra;
2259 This routine tells you how many bytes you can actually use in an
2260 allocated chunk, which may be more than you requested (although
2261 often not). You can use this many bytes without worrying about
2262 overwriting other allocated objects. Not a particularly great
2263 programming practice, but still sometimes useful.
2268 size_t malloc_usable_size(Void_t* mem)
2270 size_t malloc_usable_size(mem) Void_t* mem;
2279 if(!chunk_is_mmapped(p))
2281 if (!inuse(p)) return 0;
2282 check_inuse_chunk(p);
2283 return chunksize(p) - SIZE_SZ;
2285 return chunksize(p) - 2*SIZE_SZ;
2292 /* Utility to update current_mallinfo for malloc_stats and mallinfo() */
2295 static void malloc_update_mallinfo()
2304 INTERNAL_SIZE_T avail = chunksize(top);
2305 int navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0;
2307 for (i = 1; i < NAV; ++i)
2310 for (p = last(b); p != b; p = p->bk)
2313 check_free_chunk(p);
2314 for (q = next_chunk(p);
2315 q < top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE;
2317 check_inuse_chunk(q);
2319 avail += chunksize(p);
2324 current_mallinfo.ordblks = navail;
2325 current_mallinfo.uordblks = sbrked_mem - avail;
2326 current_mallinfo.fordblks = avail;
2327 current_mallinfo.hblks = n_mmaps;
2328 current_mallinfo.hblkhd = mmapped_mem;
2329 current_mallinfo.keepcost = chunksize(top);
2340 Prints on the amount of space obtain from the system (both
2341 via sbrk and mmap), the maximum amount (which may be more than
2342 current if malloc_trim and/or munmap got called), the maximum
2343 number of simultaneous mmap regions used, and the current number
2344 of bytes allocated via malloc (or realloc, etc) but not yet
2345 freed. (Note that this is the number of bytes allocated, not the
2346 number requested. It will be larger than the number requested
2347 because of alignment and bookkeeping overhead.)
2354 malloc_update_mallinfo();
2355 printf("max system bytes = %10u\n",
2356 (unsigned int)(max_total_mem));
2357 printf("system bytes = %10u\n",
2358 (unsigned int)(sbrked_mem + mmapped_mem));
2359 printf("in use bytes = %10u\n",
2360 (unsigned int)(current_mallinfo.uordblks + mmapped_mem));
2362 printf("max mmap regions = %10u\n",
2363 (unsigned int)max_n_mmaps);
2369 mallinfo returns a copy of updated current mallinfo.
2373 struct mallinfo mALLINFo()
2375 malloc_update_mallinfo();
2376 return current_mallinfo;
2386 mallopt is the general SVID/XPG interface to tunable parameters.
2387 The format is to provide a (parameter-number, parameter-value) pair.
2388 mallopt then sets the corresponding parameter to the argument
2389 value if it can (i.e., so long as the value is meaningful),
2390 and returns 1 if successful else 0.
2392 See descriptions of tunable parameters above.
2397 int mALLOPt(int param_number, int value)
2399 int mALLOPt(param_number, value) int param_number; int value;
2402 switch(param_number)
2404 case M_TRIM_THRESHOLD:
2405 trim_threshold = value; return 1;
2407 top_pad = value; return 1;
2408 case M_MMAP_THRESHOLD:
2409 mmap_threshold = value; return 1;
2412 n_mmaps_max = value; return 1;
2414 if (value != 0) return 0; else n_mmaps_max = value; return 1;
2422 int initf_malloc(void)
2424 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
2425 assert(gd->malloc_base); /* Set up by crt0.S */
2426 gd->malloc_limit = CONFIG_VAL(SYS_MALLOC_F_LEN);
2437 V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
2438 * return null for negative arguments
2440 * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
2441 (e.g. WIN32 platforms)
2442 * Cleanup up header file inclusion for WIN32 platforms
2443 * Cleanup code to avoid Microsoft Visual C++ compiler complaints
2444 * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
2445 memory allocation routines
2446 * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
2447 * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
2448 usage of 'assert' in non-WIN32 code
2449 * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
2451 * Always call 'fREe()' rather than 'free()'
2453 V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
2454 * Fixed ordering problem with boundary-stamping
2456 V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee)
2457 * Added pvalloc, as recommended by H.J. Liu
2458 * Added 64bit pointer support mainly from Wolfram Gloger
2459 * Added anonymously donated WIN32 sbrk emulation
2460 * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
2461 * malloc_extend_top: fix mask error that caused wastage after
2463 * Add linux mremap support code from HJ Liu
2465 V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee)
2466 * Integrated most documentation with the code.
2467 * Add support for mmap, with help from
2469 * Use last_remainder in more cases.
2471 * Use ordered bins instead of best-fit threshhold
2472 * Eliminate block-local decls to simplify tracing and debugging.
2473 * Support another case of realloc via move into top
2474 * Fix error occuring when initial sbrk_base not word-aligned.
2475 * Rely on page size for units instead of SBRK_UNIT to
2476 avoid surprises about sbrk alignment conventions.
2477 * Add mallinfo, mallopt. Thanks to Raymond Nijssen
2479 * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
2480 * More precautions for cases where other routines call sbrk,
2482 * Added macros etc., allowing use in linux libc from
2484 * Inverted this history list
2486 V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee)
2487 * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
2488 * Removed all preallocation code since under current scheme
2489 the work required to undo bad preallocations exceeds
2490 the work saved in good cases for most test programs.
2491 * No longer use return list or unconsolidated bins since
2492 no scheme using them consistently outperforms those that don't
2493 given above changes.
2494 * Use best fit for very large chunks to prevent some worst-cases.
2495 * Added some support for debugging
2497 V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee)
2498 * Removed footers when chunks are in use. Thanks to
2501 V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee)
2502 * Added malloc_trim, with help from Wolfram Gloger
2505 V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g)
2507 V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g)
2508 * realloc: try to expand in both directions
2509 * malloc: swap order of clean-bin strategy;
2510 * realloc: only conditionally expand backwards
2511 * Try not to scavenge used bins
2512 * Use bin counts as a guide to preallocation
2513 * Occasionally bin return list chunks in first scan
2516 V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g)
2517 * faster bin computation & slightly different binning
2518 * merged all consolidations to one part of malloc proper
2519 (eliminating old malloc_find_space & malloc_clean_bin)
2520 * Scan 2 returns chunks (not just 1)
2521 * Propagate failure in realloc if malloc returns 0
2522 * Add stuff to allow compilation on non-ANSI compilers
2525 V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu)
2526 * removed potential for odd address access in prev_chunk
2527 * removed dependency on getpagesize.h
2528 * misc cosmetics and a bit more internal documentation
2529 * anticosmetics: mangled names in macros to evade debugger strangeness
2530 * tested on sparc, hp-700, dec-mips, rs6000
2531 with gcc & native cc (hp, dec only) allowing
2532 Detlefs & Zorn comparison study (in SIGPLAN Notices.)
2534 Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu)
2535 * Based loosely on libg++-1.2X malloc. (It retains some of the overall
2536 structure of old version, but most details differ.)