#include "malloc.h" /* --------------------- public wrappers ---------------------- */ #ifdef USE_PUBLIC_MALLOC_WRAPPERS /* Declare all routines as internal */ #if __STD_C static Void_t* mALLOc(size_t); static void fREe(Void_t*); static Void_t* rEALLOc(Void_t*, size_t); static Void_t* mEMALIGn(size_t, size_t); static Void_t* vALLOc(size_t); static Void_t* pVALLOc(size_t); static Void_t* cALLOc(size_t, size_t); static Void_t** iCALLOc(size_t, size_t, Void_t**); static Void_t** iCOMALLOc(size_t, size_t*, Void_t**); static void cFREe(Void_t*); static int mTRIm(size_t); static size_t mUSABLe(Void_t*); static void mSTATs(); static int mALLOPt(int, int); static struct mallinfo mALLINFo(void); #else static Void_t* mALLOc(); static void fREe(); static Void_t* rEALLOc(); static Void_t* mEMALIGn(); static Void_t* vALLOc(); static Void_t* pVALLOc(); static Void_t* cALLOc(); static Void_t** iCALLOc(); static Void_t** iCOMALLOc(); static void cFREe(); static int mTRIm(); static size_t mUSABLe(); static void mSTATs(); static int mALLOPt(); static struct mallinfo mALLINFo(); #endif /* MALLOC_PREACTION and MALLOC_POSTACTION should be defined to return 0 on success, and nonzero on failure. The return value of MALLOC_POSTACTION is currently ignored in wrapper functions since there is no reasonable default action to take on failure. */ #ifdef USE_MALLOC_LOCK #ifdef WIN32 static int mALLOC_MUTEx; #define MALLOC_PREACTION slwait(&mALLOC_MUTEx) #define MALLOC_POSTACTION slrelease(&mALLOC_MUTEx) #else #include static pthread_mutex_t mALLOC_MUTEx = PTHREAD_MUTEX_INITIALIZER; #define MALLOC_PREACTION pthread_mutex_lock(&mALLOC_MUTEx) #define MALLOC_POSTACTION pthread_mutex_unlock(&mALLOC_MUTEx) #endif /* USE_MALLOC_LOCK */ #else /* Substitute anything you like for these */ /* #define MALLOC_PREACTION (0) */ /* #define MALLOC_POSTACTION (0) */ #endif Void_t* public_mALLOc(size_t bytes) { Void_t* m; if (MALLOC_PREACTION != 0) { return 0; } m = mALLOc(bytes); if (MALLOC_POSTACTION != 0) { } return m; } void public_fREe(Void_t* m) { if (MALLOC_PREACTION != 0) { return; } fREe(m); if (MALLOC_POSTACTION != 0) { } } Void_t* public_rEALLOc(Void_t* m, size_t bytes) { if (MALLOC_PREACTION != 0) { return 0; } m = rEALLOc(m, bytes); if (MALLOC_POSTACTION != 0) { } return m; } Void_t* public_mEMALIGn(size_t alignment, size_t bytes) { Void_t* m; if (MALLOC_PREACTION != 0) { return 0; } m = mEMALIGn(alignment, bytes); if (MALLOC_POSTACTION != 0) { } return m; } Void_t* public_vALLOc(size_t bytes) { Void_t* m; if (MALLOC_PREACTION != 0) { return 0; } m = vALLOc(bytes); if (MALLOC_POSTACTION != 0) { } return m; } Void_t* public_pVALLOc(size_t bytes) { Void_t* m; if (MALLOC_PREACTION != 0) { return 0; } m = pVALLOc(bytes); if (MALLOC_POSTACTION != 0) { } return m; } Void_t* public_cALLOc(size_t n, size_t elem_size) { Void_t* m; if (MALLOC_PREACTION != 0) { return 0; } m = cALLOc(n, elem_size); if (MALLOC_POSTACTION != 0) { } return m; } Void_t** public_iCALLOc(size_t n, size_t elem_size, Void_t** chunks) { Void_t** m; if (MALLOC_PREACTION != 0) { return 0; } m = iCALLOc(n, elem_size, chunks); if (MALLOC_POSTACTION != 0) { } return m; } Void_t** public_iCOMALLOc(size_t n, size_t sizes[], Void_t** chunks) { Void_t** m; if (MALLOC_PREACTION != 0) { return 0; } m = iCOMALLOc(n, sizes, chunks); if (MALLOC_POSTACTION != 0) { } return m; } STATUS public_cFREe(char* m) { if (MALLOC_PREACTION != 0) { return OK; } cFREe(m); if (MALLOC_POSTACTION != 0) { } return OK; } int public_mTRIm(size_t s) { int result; if (MALLOC_PREACTION != 0) { return 0; } result = mTRIm(s); if (MALLOC_POSTACTION != 0) { } return result; } size_t public_mUSABLe(Void_t* m) { size_t result; if (MALLOC_PREACTION != 0) { return 0; } result = mUSABLe(m); if (MALLOC_POSTACTION != 0) { } return result; } void public_mSTATs() { if (MALLOC_PREACTION != 0) { return; } mSTATs(); if (MALLOC_POSTACTION != 0) { } } struct mallinfo public_mALLINFo() { struct mallinfo m; if (MALLOC_PREACTION != 0) { struct mallinfo nm = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; return nm; } m = mALLINFo(); if (MALLOC_POSTACTION != 0) { } return m; } int public_mALLOPt(int p, int v) { int result; if (MALLOC_PREACTION != 0) { return 0; } result = mALLOPt(p, v); if (MALLOC_POSTACTION != 0) { } return result; } #endif /* ------------- Optional versions of memcopy ---------------- */ #if USE_MEMCPY /* Note: memcpy is ONLY invoked with non-overlapping regions, so the (usually slower) memmove is not needed. */ #define MALLOC_COPY(dest, src, nbytes) memcpy(dest, src, nbytes) #define MALLOC_ZERO(dest, nbytes) memset(dest, 0, nbytes) #else /* !USE_MEMCPY */ /* Use Duff's device for good zeroing/copying performance. */ #define MALLOC_ZERO(charp, nbytes) \ do { \ INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp); \ CHUNK_SIZE_T mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T); \ long mcn; \ if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ switch (mctmp) { \ case 0: for(;;) { *mzp++ = 0; \ case 7: *mzp++ = 0; \ case 6: *mzp++ = 0; \ case 5: *mzp++ = 0; \ case 4: *mzp++ = 0; \ case 3: *mzp++ = 0; \ case 2: *mzp++ = 0; \ case 1: *mzp++ = 0; if(mcn <= 0) break; mcn--; } \ } \ } while(0) #define MALLOC_COPY(dest,src,nbytes) \ do { \ INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \ INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \ CHUNK_SIZE_T mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T); \ long mcn; \ if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ switch (mctmp) { \ case 0: for(;;) { *mcdst++ = *mcsrc++; \ case 7: *mcdst++ = *mcsrc++; \ case 6: *mcdst++ = *mcsrc++; \ case 5: *mcdst++ = *mcsrc++; \ case 4: *mcdst++ = *mcsrc++; \ case 3: *mcdst++ = *mcsrc++; \ case 2: *mcdst++ = *mcsrc++; \ case 1: *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; } \ } \ } while(0) #endif /* ------------------ MMAP support ------------------ */ #if HAVE_MMAP #ifndef LACKS_FCNTL_H #include #endif #ifndef LACKS_SYS_MMAN_H #include #endif #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) #define MAP_ANONYMOUS MAP_ANON #endif /* Nearly all versions of mmap support MAP_ANONYMOUS, so the following is unlikely to be needed, but is supplied just in case. */ #ifndef MAP_ANONYMOUS static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */ #define MMAP(addr, size, prot, flags) ((dev_zero_fd < 0) ? \ (dev_zero_fd = open("/dev/zero", O_RDWR), \ mmap((addr), (size), (prot), (flags), dev_zero_fd, 0)) : \ mmap((addr), (size), (prot), (flags), dev_zero_fd, 0)) #else #define MMAP(addr, size, prot, flags) \ (mmap((addr), (size), (prot), (flags)|MAP_ANONYMOUS, -1, 0)) #endif #endif /* HAVE_MMAP */ /* ----------------------- Chunk representations ----------------------- */ /* This struct declaration is misleading (but accurate and necessary). It declares a "view" into memory allowing access to necessary fields at known offsets from a given base. See explanation below. */ struct malloc_chunk { INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */ INTERNAL_SIZE_T size; /* Size in bytes, including overhead. */ struct malloc_chunk* fd; /* double links -- used only if free. */ struct malloc_chunk* bk; }; typedef struct malloc_chunk* mchunkptr; /* malloc_chunk details: (The following includes lightly edited explanations by Colin Plumb.) Chunks of memory are maintained using a `boundary tag' method as described in e.g., Knuth or Standish. (See the paper by Paul Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such techniques.) Sizes of free chunks are stored both in the front of each chunk and at the end. This makes consolidating fragmented chunks into bigger chunks very fast. The size fields also hold bits representing whether chunks are free or in use. An allocated chunk looks like this: chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Size of previous chunk, if allocated | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Size of chunk, in bytes |P| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User data starts here... . . . . (malloc_usable_space() bytes) . . | nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Size of chunk | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where "chunk" is the front of the chunk for the purpose of most of the malloc code, but "mem" is the pointer that is returned to the user. "Nextchunk" is the beginning of the next contiguous chunk. Chunks always begin on even word boundries, so the mem portion (which is returned to the user) is also on an even word boundary, and thus at least double-word aligned. Free chunks are stored in circular doubly-linked lists, and look like this: chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Size of previous chunk | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ `head:' | Size of chunk, in bytes |P| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Forward pointer to next chunk in list | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Back pointer to previous chunk in list | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unused space (may be 0 bytes long) . . . . | nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ `foot:' | Size of chunk, in bytes | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The P (PREV_INUSE) bit, stored in the unused low-order bit of the chunk size (which is always a multiple of two words), is an in-use bit for the *previous* chunk. If that bit is *clear*, then the word before the current chunk size contains the previous chunk size, and can be used to find the front of the previous chunk. The very first chunk allocated always has this bit set, preventing access to non-existent (or non-owned) memory. If prev_inuse is set for any given chunk, then you CANNOT determine the size of the previous chunk, and might even get a memory addressing fault when trying to do so. Note that the `foot' of the current chunk is actually represented as the prev_size of the NEXT chunk. This makes it easier to deal with alignments etc but can be very confusing when trying to extend or adapt this code. The two exceptions to all this are 1. The special chunk `top' doesn't bother using the trailing size field since there is no next contiguous chunk that would have to index off it. After initialization, `top' is forced to always exist. If it would become less than MINSIZE bytes long, it is replenished. 2. Chunks allocated via mmap, which have the second-lowest-order bit (IS_MMAPPED) set in their size fields. Because they are allocated one-by-one, each must contain its own trailing size field. */ /* ---------- Size and alignment checks and conversions ---------- */ /* conversion from malloc headers to user pointers, and back */ #define chunk2mem(p) ((Void_t*)((char*)(p) + 2*SIZE_SZ)) #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ)) /* The smallest possible chunk */ #define MIN_CHUNK_SIZE (sizeof(struct malloc_chunk)) /* The smallest size we can malloc is an aligned minimal chunk */ #define MINSIZE \ (CHUNK_SIZE_T)(((MIN_CHUNK_SIZE+MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK)) /* Check if m has acceptable alignment */ #define aligned_OK(m) (((PTR_UINT)((m)) & (MALLOC_ALIGN_MASK)) == 0) /* Check if a request is so large that it would wrap around zero when padded and aligned. To simplify some other code, the bound is made low enough so that adding MINSIZE will also not wrap around sero. */ #define REQUEST_OUT_OF_RANGE(req) \ ((CHUNK_SIZE_T)(req) >= \ (CHUNK_SIZE_T)(INTERNAL_SIZE_T)(-2 * MINSIZE)) /* pad request bytes into a usable size -- internal version */ #define request2size(req) \ (((req) + SIZE_SZ + MALLOC_ALIGN_MASK < MINSIZE) ? \ MINSIZE : \ ((req) + SIZE_SZ + MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK) /* Same, except also perform argument check */ #define checked_request2size(req, sz) \ if (REQUEST_OUT_OF_RANGE(req)) { \ MALLOC_FAILURE_ACTION; \ return 0; \ } \ (sz) = request2size(req); /* --------------- Physical chunk operations --------------- */ /* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */ #define PREV_INUSE 0x1 /* extract inuse bit of previous chunk */ #define prev_inuse(p) ((p)->size & PREV_INUSE) /* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */ #define IS_MMAPPED 0x2 /* check for mmap()'ed chunk */ #define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED) /* Bits to mask off when extracting size Note: IS_MMAPPED is intentionally not masked off from size field in macros for which mmapped chunks should never be seen. This should cause helpful core dumps to occur if it is tried by accident by people extending or adapting this malloc. */ #define SIZE_BITS (PREV_INUSE|IS_MMAPPED) /* Get size, ignoring use bits */ #define chunksize(p) ((p)->size & ~(SIZE_BITS)) /* Ptr to next physical malloc_chunk. */ #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) )) /* Ptr to previous physical malloc_chunk */ #define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) )) /* Treat space at ptr + offset as a chunk */ #define chunk_at_offset(p, s) ((mchunkptr)(((char*)(p)) + (s))) /* extract p's inuse bit */ #define inuse(p)\ ((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE) /* set/clear chunk as being inuse without otherwise disturbing */ #define set_inuse(p)\ ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE #define clear_inuse(p)\ ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE) /* check/set/clear inuse bits in known places */ #define inuse_bit_at_offset(p, s)\ (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE) #define set_inuse_bit_at_offset(p, s)\ (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE) #define clear_inuse_bit_at_offset(p, s)\ (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE)) /* Set size at head, without disturbing its use bit */ #define set_head_size(p, s) ((p)->size = (((p)->size & PREV_INUSE) | (s))) /* Set size/use field */ #define set_head(p, s) ((p)->size = (s)) /* Set size at footer (only when chunk is not in use) */ #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s)) /* -------------------- Internal data structures -------------------- All internal state is held in an instance of malloc_state defined below. There are no other static variables, except in two optional cases: * If USE_MALLOC_LOCK is defined, the mALLOC_MUTEx declared above. * If HAVE_MMAP is true, but mmap doesn't support MAP_ANONYMOUS, a dummy file descriptor for mmap. Beware of lots of tricks that minimize the total bookkeeping space requirements. The result is a little over 1K bytes (for 4byte pointers and size_t.) */ /* Bins An array of bin headers for free chunks. Each bin is doubly linked. The bins are approximately proportionally (log) spaced. There are a lot of these bins (128). This may look excessive, but works very well in practice. Most bins hold sizes that are unusual as malloc request sizes, but are more usual for fragments and consolidated sets of chunks, which is what these bins hold, so they can be found quickly. All procedures maintain the invariant that no consolidated chunk physically borders another one, so each chunk in a list is known to be preceeded and followed by either inuse chunks or the ends of memory. Chunks in bins are kept in size order, with ties going to the approximately least recently used chunk. Ordering isn't needed for the small bins, which all contain the same-sized chunks, but facilitates best-fit allocation for larger chunks. These lists are just sequential. Keeping them in order almost never requires enough traversal to warrant using fancier ordered data structures. Chunks of the same size are linked with the most recently freed at the front, and allocations are taken from the back. This results in LRU (FIFO) allocation order, which tends to give each chunk an equal opportunity to be consolidated with adjacent freed chunks, resulting in larger free chunks and less fragmentation. To simplify use in double-linked lists, each bin header acts as a malloc_chunk. This avoids special-casing for headers. But to conserve space and improve locality, we allocate only the fd/bk pointers of bins, and then use repositioning tricks to treat these as the fields of a malloc_chunk*. */ typedef struct malloc_chunk* mbinptr; /* addressing -- note that bin_at(0) does not exist */ #define bin_at(m, i) ((mbinptr)((char*)&((m)->bins[(i)<<1]) - (SIZE_SZ<<1))) /* analog of ++bin */ #define next_bin(b) ((mbinptr)((char*)(b) + (sizeof(mchunkptr)<<1))) /* Reminders about list directionality within bins */ #define first(b) ((b)->fd) #define last(b) ((b)->bk) /* Take a chunk off a bin list */ #define unlink(P, BK, FD) { \ FD = P->fd; \ BK = P->bk; \ FD->bk = BK; \ BK->fd = FD; \ } /* Indexing Bins for sizes < 512 bytes contain chunks of all the same size, spaced 8 bytes apart. Larger bins are approximately logarithmically spaced: 64 bins of size 8 32 bins of size 64 16 bins of size 512 8 bins of size 4096 4 bins of size 32768 2 bins of size 262144 1 bin of size what's left The bins top out around 1MB because we expect to service large requests via mmap. */ #define NBINS 96 #define NSMALLBINS 32 #define SMALLBIN_WIDTH 8 #define MIN_LARGE_SIZE 256 #define in_smallbin_range(sz) \ ((CHUNK_SIZE_T)(sz) < (CHUNK_SIZE_T)MIN_LARGE_SIZE) #define smallbin_index(sz) (((unsigned)(sz)) >> 3) /* Compute index for size. We expect this to be inlined when compiled with optimization, else not, which works out well. */ static int largebin_index(unsigned int sz) { unsigned int x = sz >> SMALLBIN_WIDTH; unsigned int m; /* bit position of highest set bit of m */ if (x >= 0x10000) return NBINS-1; /* On intel, use BSRL instruction to find highest bit */ #if defined(__GNUC__) && defined(i386) __asm__("bsrl %1,%0\n\t" : "=r" (m) : "g" (x)); #else { /* Based on branch-free nlz algorithm in chapter 5 of Henry S. Warren Jr's book "Hacker's Delight". */ unsigned int n = ((x - 0x100) >> 16) & 8; x <<= n; m = ((x - 0x1000) >> 16) & 4; n += m; x <<= m; m = ((x - 0x4000) >> 16) & 2; n += m; x = (x << m) >> 14; m = 13 - n + (x & ~(x>>1)); } #endif /* Use next 2 bits to create finer-granularity bins */ return NSMALLBINS + (m << 2) + ((sz >> (m + 6)) & 3); } #define bin_index(sz) \ ((in_smallbin_range(sz)) ? smallbin_index(sz) : largebin_index(sz)) /* FIRST_SORTED_BIN_SIZE is the chunk size corresponding to the first bin that is maintained in sorted order. This must be the smallest size corresponding to a given bin. Normally, this should be MIN_LARGE_SIZE. But you can weaken best fit guarantees to sometimes speed up malloc by increasing value. Doing this means that malloc may choose a chunk that is non-best-fitting by up to the width of the bin. Some useful cutoff values: 512 - all bins sorted 2560 - leaves bins <= 64 bytes wide unsorted 12288 - leaves bins <= 512 bytes wide unsorted 65536 - leaves bins <= 4096 bytes wide unsorted 262144 - leaves bins <= 32768 bytes wide unsorted -1 - no bins sorted (not recommended!) */ #define FIRST_SORTED_BIN_SIZE MIN_LARGE_SIZE /* #define FIRST_SORTED_BIN_SIZE 65536 */ /* Unsorted chunks All remainders from chunk splits, as well as all returned chunks, are first placed in the "unsorted" bin. They are then placed in regular bins after malloc gives them ONE chance to be used before binning. So, basically, the unsorted_chunks list acts as a queue, with chunks being placed on it in free (and malloc_consolidate), and taken off (to be either used or placed in bins) in malloc. */ /* The otherwise unindexable 1-bin is used to hold unsorted chunks. */ #define unsorted_chunks(M) (bin_at(M, 1)) /* Top The top-most available chunk (i.e., the one bordering the end of available memory) is treated specially. It is never included in any bin, is used only if no other chunk is available, and is released back to the system if it is very large (see M_TRIM_THRESHOLD). Because top initially points to its own bin with initial zero size, thus forcing extension on the first malloc request, we avoid having any special code in malloc to check whether it even exists yet. But we still need to do so when getting memory from system, so we make initial_top treat the bin as a legal but unusable chunk during the interval between initialization and the first call to sYSMALLOc. (This is somewhat delicate, since it relies on the 2 preceding words to be zero during this interval as well.) */ /* Conveniently, the unsorted bin can be used as dummy top on first call */ #define initial_top(M) (unsorted_chunks(M)) /* Binmap To help compensate for the large number of bins, a one-level index structure is used for bin-by-bin searching. `binmap' is a bitvector recording whether bins are definitely empty so they can be skipped over during during traversals. The bits are NOT always cleared as soon as bins are empty, but instead only when they are noticed to be empty during traversal in malloc. */ /* Conservatively use 32 bits per map word, even if on 64bit system */ #define BINMAPSHIFT 5 #define BITSPERMAP (1U << BINMAPSHIFT) #define BINMAPSIZE (NBINS / BITSPERMAP) #define idx2block(i) ((i) >> BINMAPSHIFT) #define idx2bit(i) ((1U << ((i) & ((1U << BINMAPSHIFT)-1)))) #define mark_bin(m,i) ((m)->binmap[idx2block(i)] |= idx2bit(i)) #define unmark_bin(m,i) ((m)->binmap[idx2block(i)] &= ~(idx2bit(i))) #define get_binmap(m,i) ((m)->binmap[idx2block(i)] & idx2bit(i)) /* Fastbins An array of lists holding recently freed small chunks. Fastbins are not doubly linked. It is faster to single-link them, and since chunks are never removed from the middles of these lists, double linking is not necessary. Also, unlike regular bins, they are not even processed in FIFO order (they use faster LIFO) since ordering doesn't much matter in the transient contexts in which fastbins are normally used. Chunks in fastbins keep their inuse bit set, so they cannot be consolidated with other free chunks. malloc_consolidate releases all chunks in fastbins and consolidates them with other free chunks. */ typedef struct malloc_chunk* mfastbinptr; /* offset 2 to use otherwise unindexable first 2 bins */ #define fastbin_index(sz) ((((unsigned int)(sz)) >> 3) - 2) /* The maximum fastbin request size we support */ #define MAX_FAST_SIZE 80 #define NFASTBINS (fastbin_index(request2size(MAX_FAST_SIZE))+1) /* FASTBIN_CONSOLIDATION_THRESHOLD is the size of a chunk in free() that triggers automatic consolidation of possibly-surrounding fastbin chunks. This is a heuristic, so the exact value should not matter too much. It is defined at half the default trim threshold as a compromise heuristic to only attempt consolidation if it is likely to lead to trimming. However, it is not dynamically tunable, since consolidation reduces fragmentation surrounding loarge chunks even if trimming is not used. */ #define FASTBIN_CONSOLIDATION_THRESHOLD \ ((unsigned long)(DEFAULT_TRIM_THRESHOLD) >> 1) /* Since the lowest 2 bits in max_fast don't matter in size comparisons, they are used as flags. */ /* ANYCHUNKS_BIT held in max_fast indicates that there may be any freed chunks at all. It is set true when entering a chunk into any bin. */ #define ANYCHUNKS_BIT (1U) #define have_anychunks(M) (((M)->max_fast & ANYCHUNKS_BIT)) #define set_anychunks(M) ((M)->max_fast |= ANYCHUNKS_BIT) #define clear_anychunks(M) ((M)->max_fast &= ~ANYCHUNKS_BIT) /* FASTCHUNKS_BIT held in max_fast indicates that there are probably some fastbin chunks. It is set true on entering a chunk into any fastbin, and cleared only in malloc_consolidate. */ #define FASTCHUNKS_BIT (2U) #define have_fastchunks(M) (((M)->max_fast & FASTCHUNKS_BIT)) #define set_fastchunks(M) ((M)->max_fast |= (FASTCHUNKS_BIT|ANYCHUNKS_BIT)) #define clear_fastchunks(M) ((M)->max_fast &= ~(FASTCHUNKS_BIT)) /* Set value of max_fast. Use impossibly small value if 0. */ #define set_max_fast(M, s) \ (M)->max_fast = (((s) == 0)? SMALLBIN_WIDTH: request2size(s)) | \ ((M)->max_fast & (FASTCHUNKS_BIT|ANYCHUNKS_BIT)) #define get_max_fast(M) \ ((M)->max_fast & ~(FASTCHUNKS_BIT | ANYCHUNKS_BIT)) /* morecore_properties is a status word holding dynamically discovered or controlled properties of the morecore function */ #define MORECORE_CONTIGUOUS_BIT (1U) #define contiguous(M) \ (((M)->morecore_properties & MORECORE_CONTIGUOUS_BIT)) #define noncontiguous(M) \ (((M)->morecore_properties & MORECORE_CONTIGUOUS_BIT) == 0) #define set_contiguous(M) \ ((M)->morecore_properties |= MORECORE_CONTIGUOUS_BIT) #define set_noncontiguous(M) \ ((M)->morecore_properties &= ~MORECORE_CONTIGUOUS_BIT) /* ----------- Internal state representation and initialization ----------- */ struct malloc_state { /* The maximum chunk size to be eligible for fastbin */ INTERNAL_SIZE_T max_fast; /* low 2 bits used as flags */ /* Fastbins */ mfastbinptr fastbins[NFASTBINS]; /* Base of the topmost chunk -- not otherwise kept in a bin */ mchunkptr top; /* The remainder from the most recent split of a small request */ mchunkptr last_remainder; /* Normal bins packed as described above */ mchunkptr bins[NBINS * 2]; /* Bitmap of bins. Trailing zero map handles cases of largest binned size */ unsigned int binmap[BINMAPSIZE+1]; /* Tunable parameters */ CHUNK_SIZE_T trim_threshold; INTERNAL_SIZE_T top_pad; INTERNAL_SIZE_T mmap_threshold; /* Memory map support */ int n_mmaps; int n_mmaps_max; int max_n_mmaps; /* Cache malloc_getpagesize */ unsigned int pagesize; /* Track properties of MORECORE */ unsigned int morecore_properties; /* Statistics */ INTERNAL_SIZE_T mmapped_mem; INTERNAL_SIZE_T sbrked_mem; INTERNAL_SIZE_T max_sbrked_mem; INTERNAL_SIZE_T max_mmapped_mem; INTERNAL_SIZE_T max_total_mem; }; typedef struct malloc_state *mstate; /* There is exactly one instance of this struct in this malloc. If you are adapting this malloc in a way that does NOT use a static malloc_state, you MUST explicitly zero-fill it before using. This malloc relies on the property that malloc_state is initialized to all zeroes (as is true of C statics). */ static struct malloc_state av_; /* never directly referenced */ /* All uses of av_ are via get_malloc_state(). At most one "call" to get_malloc_state is made per invocation of the public versions of malloc and free, but other routines that in turn invoke malloc and/or free may call more then once. Also, it is called in check* routines if DEBUG is set. */ #define get_malloc_state() (&(av_)) /* Initialize a malloc_state struct. This is called only from within malloc_consolidate, which needs be called in the same contexts anyway. It is never called directly outside of malloc_consolidate because some optimizing compilers try to inline it at all call points, which turns out not to be an optimization at all. (Inlining it in malloc_consolidate is fine though.) */ #if __STD_C static void malloc_init_state(mstate av) #else static void malloc_init_state(av) mstate av; #endif { int i; mbinptr bin; /* Establish circular links for normal bins */ for (i = 1; i < NBINS; ++i) { bin = bin_at(av,i); bin->fd = bin->bk = bin; } av->top_pad = DEFAULT_TOP_PAD; av->n_mmaps_max = DEFAULT_MMAP_MAX; av->mmap_threshold = DEFAULT_MMAP_THRESHOLD; av->trim_threshold = DEFAULT_TRIM_THRESHOLD; #if MORECORE_CONTIGUOUS set_contiguous(av); #else set_noncontiguous(av); #endif set_max_fast(av, DEFAULT_MXFAST); av->top = initial_top(av); av->pagesize = malloc_getpagesize; } /* Other internal utilities operating on mstates */ #if __STD_C static Void_t* sYSMALLOc(INTERNAL_SIZE_T, mstate); #ifndef MORECORE_CANNOT_TRIM static int sYSTRIm(size_t, mstate); #endif static void malloc_consolidate(mstate); static Void_t** iALLOc(size_t, size_t*, int, Void_t**); #else static Void_t* sYSMALLOc(); #ifndef MORECORE_CANNOT_TRIM static int sYSTRIm(); #endif static void malloc_consolidate(); static Void_t** iALLOc(); #endif /* Debugging support These routines make a number of assertions about the states of data structures that should be true at all times. If any are not true, it's very likely that a user program has somehow trashed memory. (It's also possible that there is a coding error in malloc. In which case, please report it!) */ #if ! DEBUG #define check_chunk(P) #define check_free_chunk(P) #define check_inuse_chunk(P) #define check_remalloced_chunk(P,N) #define check_malloced_chunk(P,N) #define check_malloc_state() #else #define check_chunk(P) do_check_chunk(P) #define check_free_chunk(P) do_check_free_chunk(P) #define check_inuse_chunk(P) do_check_inuse_chunk(P) #define check_remalloced_chunk(P,N) do_check_remalloced_chunk(P,N) #define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N) #define check_malloc_state() do_check_malloc_state() /* Properties of all chunks */ #if __STD_C static void do_check_chunk(mchunkptr p) #else static void do_check_chunk(p) mchunkptr p; #endif { mstate av = get_malloc_state(); CHUNK_SIZE_T sz = chunksize(p); /* min and max possible addresses assuming contiguous allocation */ char* max_address = (char*)(av->top) + chunksize(av->top); char* min_address = max_address - av->sbrked_mem; if (!chunk_is_mmapped(p)) { /* Has legal address ... */ if (p != av->top) { if (contiguous(av)) { assert(((char*)p) >= min_address); assert(((char*)p + sz) <= ((char*)(av->top))); } } else { /* top size is always at least MINSIZE */ assert((CHUNK_SIZE_T)(sz) >= MINSIZE); /* top predecessor always marked inuse */ assert(prev_inuse(p)); } } else { #if HAVE_MMAP /* address is outside main heap */ if (contiguous(av) && av->top != initial_top(av)) { assert(((char*)p) < min_address || ((char*)p) > max_address); } /* chunk is page-aligned */ assert(((p->prev_size + sz) & (av->pagesize-1)) == 0); /* mem is aligned */ assert(aligned_OK(chunk2mem(p))); #else /* force an appropriate assert violation if debug set */ assert(!chunk_is_mmapped(p)); #endif } } /* Properties of free chunks */ #if __STD_C static void do_check_free_chunk(mchunkptr p) #else static void do_check_free_chunk(p) mchunkptr p; #endif { mstate av = get_malloc_state(); INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; mchunkptr next = chunk_at_offset(p, sz); do_check_chunk(p); /* Chunk must claim to be free ... */ assert(!inuse(p)); assert (!chunk_is_mmapped(p)); /* Unless a special marker, must have OK fields */ if ((CHUNK_SIZE_T)(sz) >= MINSIZE) { assert((sz & MALLOC_ALIGN_MASK) == 0); assert(aligned_OK(chunk2mem(p))); /* ... matching footer field */ assert(next->prev_size == sz); /* ... and is fully consolidated */ assert(prev_inuse(p)); assert (next == av->top || inuse(next)); /* ... and has minimally sane links */ assert(p->fd->bk == p); assert(p->bk->fd == p); } else /* markers are always of size SIZE_SZ */ assert(sz == SIZE_SZ); } /* Properties of inuse chunks */ #if __STD_C static void do_check_inuse_chunk(mchunkptr p) #else static void do_check_inuse_chunk(p) mchunkptr p; #endif { mstate av = get_malloc_state(); mchunkptr next; do_check_chunk(p); if (chunk_is_mmapped(p)) return; /* mmapped chunks have no next/prev */ /* Check whether it claims to be in use ... */ assert(inuse(p)); next = next_chunk(p); /* ... and is surrounded by OK chunks. Since more things can be checked with free chunks than inuse ones, if an inuse chunk borders them and debug is on, it's worth doing them. */ if (!prev_inuse(p)) { /* Note that we cannot even look at prev unless it is not inuse */ mchunkptr prv = prev_chunk(p); assert(next_chunk(prv) == p); do_check_free_chunk(prv); } if (next == av->top) { assert(prev_inuse(next)); assert(chunksize(next) >= MINSIZE); } else if (!inuse(next)) do_check_free_chunk(next); } /* Properties of chunks recycled from fastbins */ #if __STD_C static void do_check_remalloced_chunk(mchunkptr p, INTERNAL_SIZE_T s) #else static void do_check_remalloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s; #endif { INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; do_check_inuse_chunk(p); /* Legal size ... */ assert((sz & MALLOC_ALIGN_MASK) == 0); assert((CHUNK_SIZE_T)(sz) >= MINSIZE); /* ... and alignment */ assert(aligned_OK(chunk2mem(p))); /* chunk is less than MINSIZE more than request */ assert((long)(sz) - (long)(s) >= 0); assert((long)(sz) - (long)(s + MINSIZE) < 0); } /* Properties of nonrecycled chunks at the point they are malloced */ #if __STD_C static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s) #else static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s; #endif { /* same as recycled case ... */ do_check_remalloced_chunk(p, s); /* ... plus, must obey implementation invariant that prev_inuse is always true of any allocated chunk; i.e., that each allocated chunk borders either a previously allocated and still in-use chunk, or the base of its memory arena. This is ensured by making all allocations from the the `lowest' part of any found chunk. This does not necessarily hold however for chunks recycled via fastbins. */ assert(prev_inuse(p)); } /* Properties of malloc_state. This may be useful for debugging malloc, as well as detecting user programmer errors that somehow write into malloc_state. If you are extending or experimenting with this malloc, you can probably figure out how to hack this routine to print out or display chunk addresses, sizes, bins, and other instrumentation. */ static void do_check_malloc_state() { mstate av = get_malloc_state(); int i; mchunkptr p; mchunkptr q; mbinptr b; unsigned int binbit; int empty; unsigned int idx; INTERNAL_SIZE_T size; CHUNK_SIZE_T total = 0; int max_fast_bin; /* internal size_t must be no wider than pointer type */ assert(sizeof(INTERNAL_SIZE_T) <= sizeof(char*)); /* alignment is a power of 2 */ assert((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-1)) == 0); /* cannot run remaining checks until fully initialized */ if (av->top == 0 || av->top == initial_top(av)) return; /* pagesize is a power of 2 */ assert((av->pagesize & (av->pagesize-1)) == 0); /* properties of fastbins */ /* max_fast is in allowed range */ assert(get_max_fast(av) <= request2size(MAX_FAST_SIZE)); max_fast_bin = fastbin_index(av->max_fast); for (i = 0; i < (int)NFASTBINS; ++i) { p = av->fastbins[i]; /* all bins past max_fast are empty */ if (i > max_fast_bin) assert(p == 0); while (p != 0) { /* each chunk claims to be inuse */ do_check_inuse_chunk(p); total += chunksize(p); /* chunk belongs in this bin */ assert((int)fastbin_index(chunksize(p)) == i); p = p->fd; } } if (total != 0) assert(have_fastchunks(av)); else if (!have_fastchunks(av)) assert(total == 0); /* check normal bins */ for (i = 1; i < NBINS; ++i) { b = bin_at(av,i); /* binmap is accurate (except for bin 1 == unsorted_chunks) */ if (i >= 2) { binbit = get_binmap(av,i); empty = last(b) == b; if (!binbit) assert(empty); else if (!empty) assert(binbit); } for (p = last(b); p != b; p = p->bk) { /* each chunk claims to be free */ do_check_free_chunk(p); size = chunksize(p); total += size; if (i >= 2) { /* chunk belongs in bin */ idx = bin_index(size); assert((int)idx == i); /* lists are sorted */ if ((CHUNK_SIZE_T) size >= (CHUNK_SIZE_T)(FIRST_SORTED_BIN_SIZE)) { assert(p->bk == b || (CHUNK_SIZE_T)chunksize(p->bk) >= (CHUNK_SIZE_T)chunksize(p)); } } /* chunk is followed by a legal chain of inuse chunks */ for (q = next_chunk(p); (q != av->top && inuse(q) && (CHUNK_SIZE_T)(chunksize(q)) >= MINSIZE); q = next_chunk(q)) do_check_inuse_chunk(q); } } /* top chunk is OK */ check_chunk(av->top); /* sanity checks for statistics */ assert(total <= (CHUNK_SIZE_T)(av->max_total_mem)); assert(av->n_mmaps >= 0); assert(av->n_mmaps <= av->max_n_mmaps); assert((CHUNK_SIZE_T)(av->sbrked_mem) <= (CHUNK_SIZE_T)(av->max_sbrked_mem)); assert((CHUNK_SIZE_T)(av->mmapped_mem) <= (CHUNK_SIZE_T)(av->max_mmapped_mem)); assert((CHUNK_SIZE_T)(av->max_total_mem) >= (CHUNK_SIZE_T)(av->mmapped_mem) + (CHUNK_SIZE_T)(av->sbrked_mem)); } #endif /* ----------- Routines dealing with system allocation -------------- */ /* sysmalloc handles malloc cases requiring more memory from the system. On entry, it is assumed that av->top does not have enough space to service request for nb bytes, thus requiring that av->top be extended or replaced. */ #if __STD_C static Void_t* sYSMALLOc(INTERNAL_SIZE_T nb, mstate av) #else static Void_t* sYSMALLOc(nb, av) INTERNAL_SIZE_T nb; mstate av; #endif { mchunkptr old_top; /* incoming value of av->top */ INTERNAL_SIZE_T old_size; /* its size */ char* old_end; /* its end address */ long size; /* arg to first MORECORE or mmap call */ char* brk; /* return value from MORECORE */ long correction; /* arg to 2nd MORECORE call */ char* snd_brk; /* 2nd return val */ INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of new space */ INTERNAL_SIZE_T end_misalign; /* partial page left at end of new space */ char* aligned_brk; /* aligned offset into brk */ mchunkptr p; /* the allocated/returned chunk */ mchunkptr remainder; /* remainder from allocation */ CHUNK_SIZE_T remainder_size; /* its size */ CHUNK_SIZE_T sum; /* for updating stats */ size_t pagemask = av->pagesize - 1; /* If there is space available in fastbins, consolidate and retry malloc from scratch rather than getting memory from system. This can occur only if nb is in smallbin range so we didn't consolidate upon entry to malloc. It is much easier to handle this case here than in malloc proper. */ if (have_fastchunks(av)) { assert(in_smallbin_range(nb)); malloc_consolidate(av); return mALLOc(nb - MALLOC_ALIGN_MASK); } #if HAVE_MMAP /* If have mmap, and the request size meets the mmap threshold, and the system supports mmap, and there are few enough currently allocated mmapped regions, try to directly map this request rather than expanding top. */ if ((CHUNK_SIZE_T)(nb) >= (CHUNK_SIZE_T)(av->mmap_threshold) && (av->n_mmaps < av->n_mmaps_max)) { char* mm; /* return value from mmap call*/ /* Round up size to nearest page. For mmapped chunks, the overhead is one SIZE_SZ unit larger than for normal chunks, because there is no following chunk whose prev_size field could be used. */ size = (nb + SIZE_SZ + MALLOC_ALIGN_MASK + pagemask) & ~pagemask; /* Don't try if size wraps around 0 */ if ((CHUNK_SIZE_T)(size) > (CHUNK_SIZE_T)(nb)) { mm = (char*)(MMAP(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE)); if (mm != (char*)(MORECORE_FAILURE)) { /* The offset to the start of the mmapped region is stored in the prev_size field of the chunk. This allows us to adjust returned start address to meet alignment requirements here and in memalign(), and still be able to compute proper address argument for later munmap in free() and realloc(). */ front_misalign = (INTERNAL_SIZE_T)chunk2mem(mm) & MALLOC_ALIGN_MASK; if (front_misalign > 0) { correction = MALLOC_ALIGNMENT - front_misalign; p = (mchunkptr)(mm + correction); p->prev_size = correction; set_head(p, (size - correction) |IS_MMAPPED); } else { p = (mchunkptr)mm; p->prev_size = 0; set_head(p, size|IS_MMAPPED); } /* update statistics */ if (++av->n_mmaps > av->max_n_mmaps) av->max_n_mmaps = av->n_mmaps; sum = av->mmapped_mem += size; if (sum > (CHUNK_SIZE_T)(av->max_mmapped_mem)) av->max_mmapped_mem = sum; sum += av->sbrked_mem; if (sum > (CHUNK_SIZE_T)(av->max_total_mem)) av->max_total_mem = sum; check_chunk(p); return chunk2mem(p); } } } #endif /* Record incoming configuration of top */ old_top = av->top; old_size = chunksize(old_top); old_end = (char*)(chunk_at_offset(old_top, old_size)); brk = snd_brk = (char*)(MORECORE_FAILURE); /* If not the first time through, we require old_size to be at least MINSIZE and to have prev_inuse set. */ assert((old_top == initial_top(av) && old_size == 0) || ((CHUNK_SIZE_T) (old_size) >= MINSIZE && prev_inuse(old_top))); /* Precondition: not enough current space to satisfy nb request */ assert((CHUNK_SIZE_T)(old_size) < (CHUNK_SIZE_T)(nb + MINSIZE)); /* Precondition: all fastbins are consolidated */ assert(!have_fastchunks(av)); /* Request enough space for nb + pad + overhead */ size = nb + av->top_pad + MINSIZE; /* If contiguous, we can subtract out existing space that we hope to combine with new space. We add it back later only if we don't actually get contiguous space. */ if (contiguous(av)) size -= old_size; /* Round to a multiple of page size. If MORECORE is not contiguous, this ensures that we only call it with whole-page arguments. And if MORECORE is contiguous and this is not first time through, this preserves page-alignment of previous calls. Otherwise, we correct to page-align below. */ size = (size + pagemask) & ~pagemask; /* Don't try to call MORECORE if argument is so big as to appear negative. Note that since mmap takes size_t arg, it may succeed below even if we cannot call MORECORE. */ if (size > 0) brk = (char*)(MORECORE(size)); /* If have mmap, try using it as a backup when MORECORE fails or cannot be used. This is worth doing on systems that have "holes" in address space, so sbrk cannot extend to give contiguous space, but space is available elsewhere. Note that we ignore mmap max count and threshold limits, since the space will not be used as a segregated mmap region. */ #if HAVE_MMAP if (brk == (char*)(MORECORE_FAILURE)) { /* Cannot merge with old top, so add its size back in */ if (contiguous(av)) size = (size + old_size + pagemask) & ~pagemask; /* If we are relying on mmap as backup, then use larger units */ if ((CHUNK_SIZE_T)(size) < (CHUNK_SIZE_T)(MMAP_AS_MORECORE_SIZE)) size = MMAP_AS_MORECORE_SIZE; /* Don't try if size wraps around 0 */ if ((CHUNK_SIZE_T)(size) > (CHUNK_SIZE_T)(nb)) { brk = (char*)(MMAP(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE)); if (brk != (char*)(MORECORE_FAILURE)) { /* We do not need, and cannot use, another sbrk call to find end */ snd_brk = brk + size; /* Record that we no longer have a contiguous sbrk region. After the first time mmap is used as backup, we do not ever rely on contiguous space since this could incorrectly bridge regions. */ set_noncontiguous(av); } } } #endif if (brk != (char*)(MORECORE_FAILURE)) { av->sbrked_mem += size; /* If MORECORE extends previous space, we can likewise extend top size. */ if (brk == old_end && snd_brk == (char*)(MORECORE_FAILURE)) { set_head(old_top, (size + old_size) | PREV_INUSE); } /* Otherwise, make adjustments: * If the first time through or noncontiguous, we need to call sbrk just to find out where the end of memory lies. * We need to ensure that all returned chunks from malloc will meet MALLOC_ALIGNMENT * If there was an intervening foreign sbrk, we need to adjust sbrk request size to account for fact that we will not be able to combine new space with existing space in old_top. * Almost all systems internally allocate whole pages at a time, in which case we might as well use the whole last page of request. So we allocate enough more memory to hit a page boundary now, which in turn causes future contiguous calls to page-align. */ else { front_misalign = 0; end_misalign = 0; correction = 0; aligned_brk = brk; /* If MORECORE returns an address lower than we have seen before, we know it isn't really contiguous. This and some subsequent checks help cope with non-conforming MORECORE functions and the presence of "foreign" calls to MORECORE from outside of malloc or by other threads. We cannot guarantee to detect these in all cases, but cope with the ones we do detect. */ if (contiguous(av) && old_size != 0 && brk < old_end) { set_noncontiguous(av); } /* handle contiguous cases */ if (contiguous(av)) { /* We can tolerate forward non-contiguities here (usually due to foreign calls) but treat them as part of our space for stats reporting. */ if (old_size != 0) av->sbrked_mem += brk - old_end; /* Guarantee alignment of first new chunk made from this space */ front_misalign = (INTERNAL_SIZE_T)chunk2mem(brk) & MALLOC_ALIGN_MASK; if (front_misalign > 0) { /* Skip over some bytes to arrive at an aligned position. We don't need to specially mark these wasted front bytes. They will never be accessed anyway because prev_inuse of av->top (and any chunk created from its start) is always true after initialization. */ correction = MALLOC_ALIGNMENT - front_misalign; aligned_brk += correction; } /* If this isn't adjacent to existing space, then we will not be able to merge with old_top space, so must add to 2nd request. */ correction += old_size; /* Extend the end address to hit a page boundary */ end_misalign = (INTERNAL_SIZE_T)(brk + size + correction); correction += ((end_misalign + pagemask) & ~pagemask) - end_misalign; assert(correction >= 0); snd_brk = (char*)(MORECORE(correction)); if (snd_brk == (char*)(MORECORE_FAILURE)) { /* If can't allocate correction, try to at least find out current brk. It might be enough to proceed without failing. */ correction = 0; snd_brk = (char*)(MORECORE(0)); } else if (snd_brk < brk) { /* If the second call gives noncontiguous space even though it says it won't, the only course of action is to ignore results of second call, and conservatively estimate where the first call left us. Also set noncontiguous, so this won't happen again, leaving at most one hole. Note that this check is intrinsically incomplete. Because MORECORE is allowed to give more space than we ask for, there is no reliable way to detect a noncontiguity producing a forward gap for the second call. */ snd_brk = brk + size; correction = 0; set_noncontiguous(av); } } /* handle non-contiguous cases */ else { /* MORECORE/mmap must correctly align */ assert(aligned_OK(chunk2mem(brk))); /* Find out current end of memory */ if (snd_brk == (char*)(MORECORE_FAILURE)) { snd_brk = (char*)(MORECORE(0)); av->sbrked_mem += snd_brk - brk - size; } } /* Adjust top based on results of second sbrk */ if (snd_brk != (char*)(MORECORE_FAILURE)) { av->top = (mchunkptr)aligned_brk; set_head(av->top, (snd_brk - aligned_brk + correction) | PREV_INUSE); av->sbrked_mem += correction; /* If not the first time through, we either have a gap due to foreign sbrk or a non-contiguous region. Insert a double fencepost at old_top to prevent consolidation with space we don't own. These fenceposts are artificial chunks that are marked as inuse and are in any case too small to use. We need two to make sizes and alignments work out. */ if (old_size != 0) { /* Shrink old_top to insert fenceposts, keeping size a multiple of MALLOC_ALIGNMENT. We know there is at least enough space in old_top to do this. */ old_size = (old_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK; set_head(old_top, old_size | PREV_INUSE); /* Note that the following assignments completely overwrite old_top when old_size was previously MINSIZE. This is intentional. We need the fencepost, even if old_top otherwise gets lost. */ chunk_at_offset(old_top, old_size )->size = SIZE_SZ|PREV_INUSE; chunk_at_offset(old_top, old_size + SIZE_SZ)->size = SIZE_SZ|PREV_INUSE; /* If possible, release the rest, suppressing trimming. */ if (old_size >= MINSIZE) { INTERNAL_SIZE_T tt = av->trim_threshold; av->trim_threshold = (INTERNAL_SIZE_T)(-1); fREe(chunk2mem(old_top)); av->trim_threshold = tt; } } } } /* Update statistics */ sum = av->sbrked_mem; if (sum > (CHUNK_SIZE_T)(av->max_sbrked_mem)) av->max_sbrked_mem = sum; sum += av->mmapped_mem; if (sum > (CHUNK_SIZE_T)(av->max_total_mem)) av->max_total_mem = sum; check_malloc_state(); /* finally, do the allocation */ p = av->top; size = chunksize(p); /* check that one of the above allocation paths succeeded */ if ((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(nb + MINSIZE)) { remainder_size = size - nb; remainder = chunk_at_offset(p, nb); av->top = remainder; set_head(p, nb | PREV_INUSE); set_head(remainder, remainder_size | PREV_INUSE); check_malloced_chunk(p, nb); return chunk2mem(p); } } /* catch all failure paths */ MALLOC_FAILURE_ACTION; return 0; } /* sYSTRIm is an inverse of sorts to sYSMALLOc. It gives memory back to the system (via negative arguments to sbrk) if there is unused memory at the `high' end of the malloc pool. It is called automatically by free() when top space exceeds the trim threshold. It is also called by the public malloc_trim routine. It returns 1 if it actually released any memory, else 0. */ #ifndef MORECORE_CANNOT_TRIM #if __STD_C static int sYSTRIm(size_t pad, mstate av) #else static int sYSTRIm(pad, av) size_t pad; mstate av; #endif { long top_size; /* Amount of top-most memory */ long extra; /* Amount to release */ long released; /* Amount actually released */ char* current_brk; /* address returned by pre-check sbrk call */ char* new_brk; /* address returned by post-check sbrk call */ size_t pagesz; pagesz = av->pagesize; top_size = chunksize(av->top); /* Release in pagesize units, keeping at least one page */ extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz; if (extra > 0) { /* Only proceed if end of memory is where we last set it. This avoids problems if there were foreign sbrk calls. */ current_brk = (char*)(MORECORE(0)); if (current_brk == (char*)(av->top) + top_size) { /* Attempt to release memory. We ignore MORECORE return value, and instead call again to find out where new end of memory is. This avoids problems if first call releases less than we asked, of if failure somehow altered brk value. (We could still encounter problems if it altered brk in some very bad way, but the only thing we can do is adjust anyway, which will cause some downstream failure.) */ MORECORE(-extra); new_brk = (char*)(MORECORE(0)); if (new_brk != (char*)MORECORE_FAILURE) { released = (long)(current_brk - new_brk); if (released != 0) { /* Success. Adjust top. */ av->sbrked_mem -= released; set_head(av->top, (top_size - released) | PREV_INUSE); check_malloc_state(); return 1; } } } } return 0; } #endif /* ------------------------------ malloc ------------------------------ */ #if __STD_C Void_t* mALLOc(size_t bytes) #else Void_t* mALLOc(bytes) size_t bytes; #endif { mstate av = get_malloc_state(); INTERNAL_SIZE_T nb; /* normalized request size */ unsigned int idx; /* associated bin index */ mbinptr bin; /* associated bin */ mfastbinptr* fb; /* associated fastbin */ mchunkptr victim; /* inspected/selected chunk */ INTERNAL_SIZE_T size; /* its size */ int victim_index; /* its bin index */ mchunkptr remainder; /* remainder from a split */ CHUNK_SIZE_T remainder_size; /* its size */ unsigned int block; /* bit map traverser */ unsigned int bit; /* bit map traverser */ unsigned int map; /* current word of binmap */ mchunkptr fwd; /* misc temp for linking */ mchunkptr bck; /* misc temp for linking */ /* Convert request size to internal form by adding SIZE_SZ bytes overhead plus possibly more to obtain necessary alignment and/or to obtain a size of at least MINSIZE, the smallest allocatable size. Also, checked_request2size traps (returning 0) request sizes that are so large that they wrap around zero when padded and aligned. */ checked_request2size(bytes, nb); /* Bypass search if no frees yet */ if (!have_anychunks(av)) { if (av->max_fast == 0) /* initialization check */ malloc_consolidate(av); goto use_top; } /* If the size qualifies as a fastbin, first check corresponding bin. */ if ((CHUNK_SIZE_T)(nb) <= (CHUNK_SIZE_T)(av->max_fast)) { fb = &(av->fastbins[(fastbin_index(nb))]); if ( (victim = *fb) != 0) { *fb = victim->fd; check_remalloced_chunk(victim, nb); return chunk2mem(victim); } } /* If a small request, check regular bin. Since these "smallbins" hold one size each, no searching within bins is necessary. (For a large request, we need to wait until unsorted chunks are processed to find best fit. But for small ones, fits are exact anyway, so we can check now, which is faster.) */ if (in_smallbin_range(nb)) { idx = smallbin_index(nb); bin = bin_at(av,idx); if ( (victim = last(bin)) != bin) { bck = victim->bk; set_inuse_bit_at_offset(victim, nb); bin->bk = bck; bck->fd = bin; check_malloced_chunk(victim, nb); return chunk2mem(victim); } } /* If this is a large request, consolidate fastbins before continuing. While it might look excessive to kill all fastbins before even seeing if there is space available, this avoids fragmentation problems normally associated with fastbins. Also, in practice, programs tend to have runs of either small or large requests, but less often mixtures, so consolidation is not invoked all that often in most programs. And the programs that it is called frequently in otherwise tend to fragment. */ else { idx = largebin_index(nb); if (have_fastchunks(av)) malloc_consolidate(av); } /* Process recently freed or remaindered chunks, taking one only if it is exact fit, or, if this a small request, the chunk is remainder from the most recent non-exact fit. Place other traversed chunks in bins. Note that this step is the only place in any routine where chunks are placed in bins. */ while ( (victim = unsorted_chunks(av)->bk) != unsorted_chunks(av)) { bck = victim->bk; size = chunksize(victim); /* If a small request, try to use last remainder if it is the only chunk in unsorted bin. This helps promote locality for runs of consecutive small requests. This is the only exception to best-fit, and applies only when there is no exact fit for a small chunk. */ if (in_smallbin_range(nb) && bck == unsorted_chunks(av) && victim == av->last_remainder && (CHUNK_SIZE_T)(size) > (CHUNK_SIZE_T)(nb + MINSIZE)) { /* split and reattach remainder */ remainder_size = size - nb; remainder = chunk_at_offset(victim, nb); unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder; av->last_remainder = remainder; remainder->bk = remainder->fd = unsorted_chunks(av); set_head(victim, nb | PREV_INUSE); set_head(remainder, remainder_size | PREV_INUSE); set_foot(remainder, remainder_size); check_malloced_chunk(victim, nb); return chunk2mem(victim); } /* remove from unsorted list */ unsorted_chunks(av)->bk = bck; bck->fd = unsorted_chunks(av); /* Take now instead of binning if exact fit */ if (size == nb) { set_inuse_bit_at_offset(victim, size); check_malloced_chunk(victim, nb); return chunk2mem(victim); } /* place chunk in bin */ if (in_smallbin_range(size)) { victim_index = smallbin_index(size); bck = bin_at(av, victim_index); fwd = bck->fd; } else { victim_index = largebin_index(size); bck = bin_at(av, victim_index); fwd = bck->fd; if (fwd != bck) { /* if smaller than smallest, place first */ if ((CHUNK_SIZE_T)(size) < (CHUNK_SIZE_T)(bck->bk->size)) { fwd = bck; bck = bck->bk; } else if ((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(FIRST_SORTED_BIN_SIZE)) { /* maintain large bins in sorted order */ size |= PREV_INUSE; /* Or with inuse bit to speed comparisons */ while ((CHUNK_SIZE_T)(size) < (CHUNK_SIZE_T)(fwd->size)) fwd = fwd->fd; bck = fwd->bk; } } } mark_bin(av, victim_index); victim->bk = bck; victim->fd = fwd; fwd->bk = victim; bck->fd = victim; } /* If a large request, scan through the chunks of current bin to find one that fits. (This will be the smallest that fits unless FIRST_SORTED_BIN_SIZE has been changed from default.) This is the only step where an unbounded number of chunks might be scanned without doing anything useful with them. However the lists tend to be short. */ if (!in_smallbin_range(nb)) { bin = bin_at(av, idx); for (victim = last(bin); victim != bin; victim = victim->bk) { size = chunksize(victim); if ((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(nb)) { remainder_size = size - nb; unlink(victim, bck, fwd); /* Exhaust */ if (remainder_size < MINSIZE) { set_inuse_bit_at_offset(victim, size); check_malloced_chunk(victim, nb); return chunk2mem(victim); } /* Split */ else { remainder = chunk_at_offset(victim, nb); unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder; remainder->bk = remainder->fd = unsorted_chunks(av); set_head(victim, nb | PREV_INUSE); set_head(remainder, remainder_size | PREV_INUSE); set_foot(remainder, remainder_size); check_malloced_chunk(victim, nb); return chunk2mem(victim); } } } } /* Search for a chunk by scanning bins, starting with next largest bin. This search is strictly by best-fit; i.e., the smallest (with ties going to approximately the least recently used) chunk that fits is selected. The bitmap avoids needing to check that most blocks are nonempty. */ ++idx; bin = bin_at(av,idx); block = idx2block(idx); map = av->binmap[block]; bit = idx2bit(idx); for (;;) { /* Skip rest of block if there are no more set bits in this block. */ if (bit > map || bit == 0) { do { if (++block >= BINMAPSIZE) /* out of bins */ goto use_top; } while ( (map = av->binmap[block]) == 0); bin = bin_at(av, (block << BINMAPSHIFT)); bit = 1; } /* Advance to bin with set bit. There must be one. */ while ((bit & map) == 0) { bin = next_bin(bin); bit <<= 1; assert(bit != 0); } /* Inspect the bin. It is likely to be non-empty */ victim = last(bin); /* If a false alarm (empty bin), clear the bit. */ if (victim == bin) { av->binmap[block] = map &= ~bit; /* Write through */ bin = next_bin(bin); bit <<= 1; } else { size = chunksize(victim); /* We know the first chunk in this bin is big enough to use. */ assert((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(nb)); remainder_size = size - nb; /* unlink */ bck = victim->bk; bin->bk = bck; bck->fd = bin; /* Exhaust */ if (remainder_size < MINSIZE) { set_inuse_bit_at_offset(victim, size); check_malloced_chunk(victim, nb); return chunk2mem(victim); } /* Split */ else { remainder = chunk_at_offset(victim, nb); unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder; remainder->bk = remainder->fd = unsorted_chunks(av); /* advertise as last remainder */ if (in_smallbin_range(nb)) av->last_remainder = remainder; set_head(victim, nb | PREV_INUSE); set_head(remainder, remainder_size | PREV_INUSE); set_foot(remainder, remainder_size); check_malloced_chunk(victim, nb); return chunk2mem(victim); } } } use_top: /* If large enough, split off the chunk bordering the end of memory (held in av->top). Note that this is in accord with the best-fit search rule. In effect, av->top is treated as larger (and thus less well fitting) than any other available chunk since it can be extended to be as large as necessary (up to system limitations). We require that av->top always exists (i.e., has size >= MINSIZE) after initialization, so if it would otherwise be exhuasted by current request, it is replenished. (The main reason for ensuring it exists is that we may need MINSIZE space to put in fenceposts in sysmalloc.) */ victim = av->top; size = chunksize(victim); if ((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(nb + MINSIZE)) { remainder_size = size - nb; remainder = chunk_at_offset(victim, nb); av->top = remainder; set_head(victim, nb | PREV_INUSE); set_head(remainder, remainder_size | PREV_INUSE); check_malloced_chunk(victim, nb); return chunk2mem(victim); } /* If no space in top, relay to handle system-dependent cases */ return sYSMALLOc(nb, av); } /* ------------------------------ free ------------------------------ */ #if __STD_C void fREe(Void_t* mem) #else void fREe(mem) Void_t* mem; #endif { mstate av = get_malloc_state(); mchunkptr p; /* chunk corresponding to mem */ INTERNAL_SIZE_T size; /* its size */ mfastbinptr* fb; /* associated fastbin */ mchunkptr nextchunk; /* next contiguous chunk */ INTERNAL_SIZE_T nextsize; /* its size */ int nextinuse; /* true if nextchunk is used */ INTERNAL_SIZE_T prevsize; /* size of previous contiguous chunk */ mchunkptr bck; /* misc temp for linking */ mchunkptr fwd; /* misc temp for linking */ /* free(0) has no effect */ if (mem != 0) { p = mem2chunk(mem); size = chunksize(p); check_inuse_chunk(p); /* If eligible, place chunk on a fastbin so it can be found and used quickly in malloc. */ if ((CHUNK_SIZE_T)(size) <= (CHUNK_SIZE_T)(av->max_fast) #if TRIM_FASTBINS /* If TRIM_FASTBINS set, don't place chunks bordering top into fastbins */ && (chunk_at_offset(p, size) != av->top) #endif ) { set_fastchunks(av); fb = &(av->fastbins[fastbin_index(size)]); p->fd = *fb; *fb = p; } /* Consolidate other non-mmapped chunks as they arrive. */ else if (!chunk_is_mmapped(p)) { set_anychunks(av); nextchunk = chunk_at_offset(p, size); nextsize = chunksize(nextchunk); /* consolidate backward */ if (!prev_inuse(p)) { prevsize = p->prev_size; size += prevsize; p = chunk_at_offset(p, -((long) prevsize)); unlink(p, bck, fwd); } if (nextchunk != av->top) { /* get and clear inuse bit */ nextinuse = inuse_bit_at_offset(nextchunk, nextsize); set_head(nextchunk, nextsize); /* consolidate forward */ if (!nextinuse) { unlink(nextchunk, bck, fwd); size += nextsize; } /* Place the chunk in unsorted chunk list. Chunks are not placed into regular bins until after they have been given one chance to be used in malloc. */ bck = unsorted_chunks(av); fwd = bck->fd; p->bk = bck; p->fd = fwd; bck->fd = p; fwd->bk = p; set_head(p, size | PREV_INUSE); set_foot(p, size); check_free_chunk(p); } /* If the chunk borders the current high end of memory, consolidate into top */ else { size += nextsize; set_head(p, size | PREV_INUSE); av->top = p; check_chunk(p); } /* If freeing a large space, consolidate possibly-surrounding chunks. Then, if the total unused topmost memory exceeds trim threshold, ask malloc_trim to reduce top. Unless max_fast is 0, we don't know if there are fastbins bordering top, so we cannot tell for sure whether threshold has been reached unless fastbins are consolidated. But we don't want to consolidate on each free. As a compromise, consolidation is performed if FASTBIN_CONSOLIDATION_THRESHOLD is reached. */ if ((CHUNK_SIZE_T)(size) >= FASTBIN_CONSOLIDATION_THRESHOLD) { if (have_fastchunks(av)) malloc_consolidate(av); #ifndef MORECORE_CANNOT_TRIM if ((CHUNK_SIZE_T)(chunksize(av->top)) >= (CHUNK_SIZE_T)(av->trim_threshold)) sYSTRIm(av->top_pad, av); #endif } } /* If the chunk was allocated via mmap, release via munmap() Note that if HAVE_MMAP is false but chunk_is_mmapped is true, then user must have overwritten memory. There's nothing we can do to catch this error unless DEBUG is set, in which case check_inuse_chunk (above) will have triggered error. */ else { #if HAVE_MMAP int ret; INTERNAL_SIZE_T offset = p->prev_size; av->n_mmaps--; av->mmapped_mem -= (size + offset); ret = munmap((char*)p - offset, size + offset); /* munmap returns non-zero on failure */ assert(ret == 0); #endif } } } /* ------------------------- malloc_consolidate ------------------------- malloc_consolidate is a specialized version of free() that tears down chunks held in fastbins. Free itself cannot be used for this purpose since, among other things, it might place chunks back onto fastbins. So, instead, we need to use a minor variant of the same code. Also, because this routine needs to be called the first time through malloc anyway, it turns out to be the perfect place to trigger initialization code. */ #if __STD_C static void malloc_consolidate(mstate av) #else static void malloc_consolidate(av) mstate av; #endif { mfastbinptr* fb; /* current fastbin being consolidated */ mfastbinptr* maxfb; /* last fastbin (for loop control) */ mchunkptr p; /* current chunk being consolidated */ mchunkptr nextp; /* next chunk to consolidate */ mchunkptr unsorted_bin; /* bin header */ mchunkptr first_unsorted; /* chunk to link to */ /* These have same use as in free() */ mchunkptr nextchunk; INTERNAL_SIZE_T size; INTERNAL_SIZE_T nextsize; INTERNAL_SIZE_T prevsize; int nextinuse; mchunkptr bck; mchunkptr fwd; /* If max_fast is 0, we know that av hasn't yet been initialized, in which case do so below */ if (av->max_fast != 0) { clear_fastchunks(av); unsorted_bin = unsorted_chunks(av); /* Remove each chunk from fast bin and consolidate it, placing it then in unsorted bin. Among other reasons for doing this, placing in unsorted bin avoids needing to calculate actual bins until malloc is sure that chunks aren't immediately going to be reused anyway. */ maxfb = &(av->fastbins[fastbin_index(av->max_fast)]); fb = &(av->fastbins[0]); do { if ( (p = *fb) != 0) { *fb = 0; do { check_inuse_chunk(p); nextp = p->fd; /* Slightly streamlined version of consolidation code in free() */ size = p->size & ~PREV_INUSE; nextchunk = chunk_at_offset(p, size); nextsize = chunksize(nextchunk); if (!prev_inuse(p)) { prevsize = p->prev_size; size += prevsize; p = chunk_at_offset(p, -((long) prevsize)); unlink(p, bck, fwd); } if (nextchunk != av->top) { nextinuse = inuse_bit_at_offset(nextchunk, nextsize); set_head(nextchunk, nextsize); if (!nextinuse) { size += nextsize; unlink(nextchunk, bck, fwd); } first_unsorted = unsorted_bin->fd; unsorted_bin->fd = p; first_unsorted->bk = p; set_head(p, size | PREV_INUSE); p->bk = unsorted_bin; p->fd = first_unsorted; set_foot(p, size); } else { size += nextsize; set_head(p, size | PREV_INUSE); av->top = p; } } while ( (p = nextp) != 0); } } while (fb++ != maxfb); } else { malloc_init_state(av); check_malloc_state(); } } /* ------------------------------ realloc ------------------------------ */ #if __STD_C Void_t* rEALLOc(Void_t* oldmem, size_t bytes) #else Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes; #endif { mstate av = get_malloc_state(); INTERNAL_SIZE_T nb; /* padded request size */ mchunkptr oldp; /* chunk corresponding to oldmem */ INTERNAL_SIZE_T oldsize; /* its size */ mchunkptr newp; /* chunk to return */ INTERNAL_SIZE_T newsize; /* its size */ Void_t* newmem; /* corresponding user mem */ mchunkptr next; /* next contiguous chunk after oldp */ mchunkptr remainder; /* extra space at end of newp */ CHUNK_SIZE_T remainder_size; /* its size */ mchunkptr bck; /* misc temp for linking */ mchunkptr fwd; /* misc temp for linking */ CHUNK_SIZE_T copysize; /* bytes to copy */ unsigned int ncopies; /* INTERNAL_SIZE_T words to copy */ INTERNAL_SIZE_T* s; /* copy source */ INTERNAL_SIZE_T* d; /* copy destination */ #ifdef REALLOC_ZERO_BYTES_FREES if (bytes == 0) { fREe(oldmem); return 0; } #endif /* realloc of null is supposed to be same as malloc */ if (oldmem == 0) return mALLOc(bytes); checked_request2size(bytes, nb); oldp = mem2chunk(oldmem); oldsize = chunksize(oldp); check_inuse_chunk(oldp); if (!chunk_is_mmapped(oldp)) { if ((CHUNK_SIZE_T)(oldsize) >= (CHUNK_SIZE_T)(nb)) { /* already big enough; split below */ newp = oldp; newsize = oldsize; } else { next = chunk_at_offset(oldp, oldsize); /* Try to expand forward into top */ if (next == av->top && (CHUNK_SIZE_T)(newsize = oldsize + chunksize(next)) >= (CHUNK_SIZE_T)(nb + MINSIZE)) { set_head_size(oldp, nb); av->top = chunk_at_offset(oldp, nb); set_head(av->top, (newsize - nb) | PREV_INUSE); return chunk2mem(oldp); } /* Try to expand forward into next chunk; split off remainder below */ else if (next != av->top && !inuse(next) && (CHUNK_SIZE_T)(newsize = oldsize + chunksize(next)) >= (CHUNK_SIZE_T)(nb)) { newp = oldp; unlink(next, bck, fwd); } /* allocate, copy, free */ else { newmem = mALLOc(nb - MALLOC_ALIGN_MASK); if (newmem == 0) return 0; /* propagate failure */ newp = mem2chunk(newmem); newsize = chunksize(newp); /* Avoid copy if newp is next chunk after oldp. */ if (newp == next) { newsize += oldsize; newp = oldp; } else { /* Unroll copy of <= 36 bytes (72 if 8byte sizes) We know that contents have an odd number of INTERNAL_SIZE_T-sized words; minimally 3. */ copysize = oldsize - SIZE_SZ; s = (INTERNAL_SIZE_T*)(oldmem); d = (INTERNAL_SIZE_T*)(newmem); ncopies = copysize / sizeof(INTERNAL_SIZE_T); assert(ncopies >= 3); if (ncopies > 9) MALLOC_COPY(d, s, copysize); else { *(d+0) = *(s+0); *(d+1) = *(s+1); *(d+2) = *(s+2); if (ncopies > 4) { *(d+3) = *(s+3); *(d+4) = *(s+4); if (ncopies > 6) { *(d+5) = *(s+5); *(d+6) = *(s+6); if (ncopies > 8) { *(d+7) = *(s+7); *(d+8) = *(s+8); } } } } fREe(oldmem); check_inuse_chunk(newp); return chunk2mem(newp); } } } /* If possible, free extra space in old or extended chunk */ assert((CHUNK_SIZE_T)(newsize) >= (CHUNK_SIZE_T)(nb)); remainder_size = newsize - nb; if (remainder_size < MINSIZE) { /* not enough extra to split off */ set_head_size(newp, newsize); set_inuse_bit_at_offset(newp, newsize); } else { /* split remainder */ remainder = chunk_at_offset(newp, nb); set_head_size(newp, nb); set_head(remainder, remainder_size | PREV_INUSE); /* Mark remainder as inuse so free() won't complain */ set_inuse_bit_at_offset(remainder, remainder_size); fREe(chunk2mem(remainder)); } check_inuse_chunk(newp); return chunk2mem(newp); } /* Handle mmap cases */ else { #if HAVE_MMAP #if HAVE_MREMAP INTERNAL_SIZE_T offset = oldp->prev_size; size_t pagemask = av->pagesize - 1; char *cp; CHUNK_SIZE_T sum; /* Note the extra SIZE_SZ overhead */ newsize = (nb + offset + SIZE_SZ + pagemask) & ~pagemask; /* don't need to remap if still within same page */ if (oldsize == newsize - offset) return oldmem; cp = (char*)mremap((char*)oldp - offset, oldsize + offset, newsize, 1); if (cp != (char*)MORECORE_FAILURE) { newp = (mchunkptr)(cp + offset); set_head(newp, (newsize - offset)|IS_MMAPPED); assert(aligned_OK(chunk2mem(newp))); assert((newp->prev_size == offset)); /* update statistics */ sum = av->mmapped_mem += newsize - oldsize; if (sum > (CHUNK_SIZE_T)(av->max_mmapped_mem)) av->max_mmapped_mem = sum; sum += av->sbrked_mem; if (sum > (CHUNK_SIZE_T)(av->max_total_mem)) av->max_total_mem = sum; return chunk2mem(newp); } #endif /* Note the extra SIZE_SZ overhead. */ if ((CHUNK_SIZE_T)(oldsize) >= (CHUNK_SIZE_T)(nb + SIZE_SZ)) newmem = oldmem; /* do nothing */ else { /* Must alloc, copy, free. */ newmem = mALLOc(nb - MALLOC_ALIGN_MASK); if (newmem != 0) { MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ); fREe(oldmem); } } return newmem; #else /* If !HAVE_MMAP, but chunk_is_mmapped, user must have overwritten mem */ check_malloc_state(); MALLOC_FAILURE_ACTION; return 0; #endif } } /* ------------------------------ memalign ------------------------------ */ #if __STD_C Void_t* mEMALIGn(size_t alignment, size_t bytes) #else Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes; #endif { INTERNAL_SIZE_T nb; /* padded request size */ char* m; /* memory returned by malloc call */ mchunkptr p; /* corresponding chunk */ char* brk; /* alignment point within p */ mchunkptr newp; /* chunk to return */ INTERNAL_SIZE_T newsize; /* its size */ INTERNAL_SIZE_T leadsize; /* leading space before alignment point */ mchunkptr remainder; /* spare room at end to split off */ CHUNK_SIZE_T remainder_size; /* its size */ INTERNAL_SIZE_T size; /* If need less alignment than we give anyway, just relay to malloc */ if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes); /* Otherwise, ensure that it is at least a minimum chunk size */ if (alignment < MINSIZE) alignment = MINSIZE; /* Make sure alignment is power of 2 (in case MINSIZE is not). */ if ((alignment & (alignment - 1)) != 0) { size_t a = MALLOC_ALIGNMENT * 2; while ((CHUNK_SIZE_T)a < (CHUNK_SIZE_T)alignment) a <<= 1; alignment = a; } checked_request2size(bytes, nb); /* Strategy: find a spot within that chunk that meets the alignment request, and then possibly free the leading and trailing space. */ /* Call malloc with worst case padding to hit alignment. */ m = (char*)(mALLOc(nb + alignment + MINSIZE)); if (m == 0) return 0; /* propagate failure */ p = mem2chunk(m); if ((((PTR_UINT)(m)) % alignment) != 0) { /* misaligned */ /* Find an aligned spot inside chunk. Since we need to give back leading space in a chunk of at least MINSIZE, if the first calculation places us at a spot with less than MINSIZE leader, we can move to the next aligned spot -- we've allocated enough total room so that this is always possible. */ brk = (char*)mem2chunk((PTR_UINT)(((PTR_UINT)(m + alignment - 1)) & -((signed long) alignment))); if ((CHUNK_SIZE_T)(brk - (char*)(p)) < MINSIZE) brk += alignment; newp = (mchunkptr)brk; leadsize = brk - (char*)(p); newsize = chunksize(p) - leadsize; /* For mmapped chunks, just adjust offset */ if (chunk_is_mmapped(p)) { newp->prev_size = p->prev_size + leadsize; set_head(newp, newsize|IS_MMAPPED); return chunk2mem(newp); } /* Otherwise, give back leader, use the rest */ set_head(newp, newsize | PREV_INUSE); set_inuse_bit_at_offset(newp, newsize); set_head_size(p, leadsize); fREe(chunk2mem(p)); p = newp; assert (newsize >= nb && (((PTR_UINT)(chunk2mem(p))) % alignment) == 0); } /* Also give back spare room at the end */ if (!chunk_is_mmapped(p)) { size = chunksize(p); if ((CHUNK_SIZE_T)(size) > (CHUNK_SIZE_T)(nb + MINSIZE)) { remainder_size = size - nb; remainder = chunk_at_offset(p, nb); set_head(remainder, remainder_size | PREV_INUSE); set_head_size(p, nb); fREe(chunk2mem(remainder)); } } check_inuse_chunk(p); return chunk2mem(p); } /* ------------------------------ calloc ------------------------------ */ #if __STD_C Void_t* cALLOc(size_t n_elements, size_t elem_size) #else Void_t* cALLOc(n_elements, elem_size) size_t n_elements; size_t elem_size; #endif { mchunkptr p; CHUNK_SIZE_T clearsize; CHUNK_SIZE_T nclears; INTERNAL_SIZE_T* d; Void_t* mem = mALLOc(n_elements * elem_size); if (mem != 0) { p = mem2chunk(mem); if (!chunk_is_mmapped(p)) { /* Unroll clear of <= 36 bytes (72 if 8byte sizes) We know that contents have an odd number of INTERNAL_SIZE_T-sized words; minimally 3. */ d = (INTERNAL_SIZE_T*)mem; clearsize = chunksize(p) - SIZE_SZ; nclears = clearsize / sizeof(INTERNAL_SIZE_T); assert(nclears >= 3); if (nclears > 9) MALLOC_ZERO(d, clearsize); else { *(d+0) = 0; *(d+1) = 0; *(d+2) = 0; if (nclears > 4) { *(d+3) = 0; *(d+4) = 0; if (nclears > 6) { *(d+5) = 0; *(d+6) = 0; if (nclears > 8) { *(d+7) = 0; *(d+8) = 0; } } } } } #if ! MMAP_CLEARS else { d = (INTERNAL_SIZE_T*)mem; /* Note the additional SIZE_SZ */ clearsize = chunksize(p) - 2*SIZE_SZ; MALLOC_ZERO(d, clearsize); } #endif } return mem; } /* ------------------------------ cfree ------------------------------ */ #if __STD_C void cFREe(Void_t *mem) #else void cFREe(mem) Void_t *mem; #endif { fREe(mem); } /* ------------------------- independent_calloc ------------------------- */ #if __STD_C Void_t** iCALLOc(size_t n_elements, size_t elem_size, Void_t* chunks[]) #else Void_t** iCALLOc(n_elements, elem_size, chunks) size_t n_elements; size_t elem_size; Void_t* chunks[]; #endif { size_t sz = elem_size; /* serves as 1-element array */ /* opts arg of 3 means all elements are same size, and should be cleared */ return iALLOc(n_elements, &sz, 3, chunks); } /* ------------------------- independent_comalloc ------------------------- */ #if __STD_C Void_t** iCOMALLOc(size_t n_elements, size_t sizes[], Void_t* chunks[]) #else Void_t** iCOMALLOc(n_elements, sizes, chunks) size_t n_elements; size_t sizes[]; Void_t* chunks[]; #endif { return iALLOc(n_elements, sizes, 0, chunks); } /* ------------------------------ ialloc ------------------------------ ialloc provides common support for independent_X routines, handling all of the combinations that can result. The opts arg has: bit 0 set if all elements are same size (using sizes[0]) bit 1 set if elements should be zeroed */ #if __STD_C static Void_t** iALLOc(size_t n_elements, size_t* sizes, int opts, Void_t* chunks[]) #else static Void_t** iALLOc(n_elements, sizes, opts, chunks) size_t n_elements; size_t* sizes; int opts; Void_t* chunks[]; #endif { mstate av = get_malloc_state(); INTERNAL_SIZE_T element_size; /* chunksize of each element, if all same */ INTERNAL_SIZE_T contents_size; /* total size of elements */ INTERNAL_SIZE_T array_size; /* request size of pointer array */ Void_t* mem; /* malloced aggregate space */ mchunkptr p; /* corresponding chunk */ INTERNAL_SIZE_T remainder_size; /* remaining bytes while splitting */ Void_t** marray; /* either "chunks" or malloced ptr array */ mchunkptr array_chunk; /* chunk for malloced ptr array */ int mmx; /* to disable mmap */ INTERNAL_SIZE_T size; size_t i; /* Ensure initialization */ if (av->max_fast == 0) malloc_consolidate(av); /* compute array length, if needed */ if (chunks != 0) { if (n_elements == 0) return chunks; /* nothing to do */ marray = chunks; array_size = 0; } else { /* if empty req, must still return chunk representing empty array */ if (n_elements == 0) return (Void_t**) mALLOc(0); marray = 0; array_size = request2size(n_elements * (sizeof(Void_t*))); } /* compute total element size */ if (opts & 0x1) { /* all-same-size */ element_size = request2size(*sizes); contents_size = n_elements * element_size; } else { /* add up all the sizes */ element_size = 0; contents_size = 0; for (i = 0; i != n_elements; ++i) contents_size += request2size(sizes[i]); } /* subtract out alignment bytes from total to minimize overallocation */ size = contents_size + array_size - MALLOC_ALIGN_MASK; /* Allocate the aggregate chunk. But first disable mmap so malloc won't use it, since we would not be able to later free/realloc space internal to a segregated mmap region. */ mmx = av->n_mmaps_max; /* disable mmap */ av->n_mmaps_max = 0; mem = mALLOc(size); av->n_mmaps_max = mmx; /* reset mmap */ if (mem == 0) return 0; p = mem2chunk(mem); assert(!chunk_is_mmapped(p)); remainder_size = chunksize(p); if (opts & 0x2) { /* optionally clear the elements */ MALLOC_ZERO(mem, remainder_size - SIZE_SZ - array_size); } /* If not provided, allocate the pointer array as final part of chunk */ if (marray == 0) { array_chunk = chunk_at_offset(p, contents_size); marray = (Void_t**) (chunk2mem(array_chunk)); set_head(array_chunk, (remainder_size - contents_size) | PREV_INUSE); remainder_size = contents_size; } /* split out elements */ for (i = 0; ; ++i) { marray[i] = chunk2mem(p); if (i != n_elements-1) { if (element_size != 0) size = element_size; else size = request2size(sizes[i]); remainder_size -= size; set_head(p, size | PREV_INUSE); p = chunk_at_offset(p, size); } else { /* the final element absorbs any overallocation slop */ set_head(p, remainder_size | PREV_INUSE); break; } } #if DEBUG if (marray != chunks) { /* final element must have exactly exhausted chunk */ if (element_size != 0) assert(remainder_size == element_size); else assert(remainder_size == request2size(sizes[i])); check_inuse_chunk(mem2chunk(marray)); } for (i = 0; i != n_elements; ++i) check_inuse_chunk(mem2chunk(marray[i])); #endif return marray; } /* ------------------------------ valloc ------------------------------ */ #if __STD_C Void_t* vALLOc(size_t bytes) #else Void_t* vALLOc(bytes) size_t bytes; #endif { /* Ensure initialization */ mstate av = get_malloc_state(); if (av->max_fast == 0) malloc_consolidate(av); return mEMALIGn(av->pagesize, bytes); } /* ------------------------------ pvalloc ------------------------------ */ #if __STD_C Void_t* pVALLOc(size_t bytes) #else Void_t* pVALLOc(bytes) size_t bytes; #endif { mstate av = get_malloc_state(); size_t pagesz; /* Ensure initialization */ if (av->max_fast == 0) malloc_consolidate(av); pagesz = av->pagesize; return mEMALIGn(pagesz, (bytes + pagesz - 1) & ~(pagesz - 1)); } /* ------------------------------ malloc_trim ------------------------------ */ #if __STD_C int mTRIm(size_t pad) #else int mTRIm(pad) size_t pad; #endif { mstate av = get_malloc_state(); /* Ensure initialization/consolidation */ malloc_consolidate(av); #ifndef MORECORE_CANNOT_TRIM return sYSTRIm(pad, av); #else return 0; #endif } /* ------------------------- malloc_usable_size ------------------------- */ #if __STD_C size_t mUSABLe(Void_t* mem) #else size_t mUSABLe(mem) Void_t* mem; #endif { mchunkptr p; if (mem != 0) { p = mem2chunk(mem); if (chunk_is_mmapped(p)) return chunksize(p) - 2*SIZE_SZ; else if (inuse(p)) return chunksize(p) - SIZE_SZ; } return 0; } /* ------------------------------ mallinfo ------------------------------ */ struct mallinfo mALLINFo() { mstate av = get_malloc_state(); struct mallinfo mi; int i; mbinptr b; mchunkptr p; INTERNAL_SIZE_T avail; INTERNAL_SIZE_T fastavail; int nblocks; int nfastblocks; /* Ensure initialization */ if (av->top == 0) malloc_consolidate(av); check_malloc_state(); /* Account for top */ avail = chunksize(av->top); nblocks = 1; /* top always exists */ /* traverse fastbins */ nfastblocks = 0; fastavail = 0; for (i = 0; i < (int)NFASTBINS; ++i) { for (p = av->fastbins[i]; p != 0; p = p->fd) { ++nfastblocks; fastavail += chunksize(p); } } avail += fastavail; /* traverse regular bins */ for (i = 1; i < NBINS; ++i) { b = bin_at(av, i); for (p = last(b); p != b; p = p->bk) { ++nblocks; avail += chunksize(p); } } mi.smblks = nfastblocks; mi.ordblks = nblocks; mi.fordblks = avail; mi.uordblks = av->sbrked_mem - avail; mi.arena = av->sbrked_mem; mi.hblks = av->n_mmaps; mi.hblkhd = av->mmapped_mem; mi.fsmblks = fastavail; mi.keepcost = chunksize(av->top); mi.usmblks = av->max_total_mem; return mi; } /* ------------------------------ malloc_stats ------------------------------ */ void mSTATs() { struct mallinfo mi = mALLINFo(); #ifdef WIN32 { CHUNK_SIZE_T free, reserved, committed; vminfo (&free, &reserved, &committed); fprintf(stderr, "free bytes = %10lu\n", free); fprintf(stderr, "reserved bytes = %10lu\n", reserved); fprintf(stderr, "committed bytes = %10lu\n", committed); } #endif fprintf(stderr, "max system bytes = %10lu\n", (CHUNK_SIZE_T)(mi.usmblks)); fprintf(stderr, "system bytes = %10lu\n", (CHUNK_SIZE_T)(mi.arena + mi.hblkhd)); fprintf(stderr, "in use bytes = %10lu\n", (CHUNK_SIZE_T)(mi.uordblks + mi.hblkhd)); #ifdef WIN32 { CHUNK_SIZE_T kernel, user; if (cpuinfo (TRUE, &kernel, &user)) { fprintf(stderr, "kernel ms = %10lu\n", kernel); fprintf(stderr, "user ms = %10lu\n", user); } } #endif } /* ------------------------------ mallopt ------------------------------ */ #if __STD_C int mALLOPt(int param_number, int value) #else int mALLOPt(param_number, value) int param_number; int value; #endif { mstate av = get_malloc_state(); /* Ensure initialization/consolidation */ malloc_consolidate(av); switch(param_number) { case M_MXFAST: if (value >= 0 && value <= MAX_FAST_SIZE) { set_max_fast(av, value); return 1; } else return 0; case M_TRIM_THRESHOLD: av->trim_threshold = value; return 1; case M_TOP_PAD: av->top_pad = value; return 1; case M_MMAP_THRESHOLD: av->mmap_threshold = value; return 1; case M_MMAP_MAX: #if !HAVE_MMAP if (value != 0) return 0; #endif av->n_mmaps_max = value; return 1; default: return 0; } } /* #include "malloc.extra.c" */ void vxMemInit(void) { semBInit(&mem_semaphore, SEM_Q_PRIORITY, SEM_FULL); } /* -------------------- Alternative MORECORE functions -------------------- */ /* General Requirements for MORECORE. The MORECORE function must have the following properties: If MORECORE_CONTIGUOUS is false: * MORECORE must allocate in multiples of pagesize. It will only be called with arguments that are multiples of pagesize. * MORECORE(0) must return an address that is at least MALLOC_ALIGNMENT aligned. (Page-aligning always suffices.) else (i.e. If MORECORE_CONTIGUOUS is true): * Consecutive calls to MORECORE with positive arguments return increasing addresses, indicating that space has been contiguously extended. * MORECORE need not allocate in multiples of pagesize. Calls to MORECORE need not have args of multiples of pagesize. * MORECORE need not page-align. In either case: * MORECORE may allocate more memory than requested. (Or even less, but this will generally result in a malloc failure.) * MORECORE must not allocate memory when given argument zero, but instead return one past the end address of memory from previous nonzero call. This malloc does NOT call MORECORE(0) until at least one call with positive arguments is made, so the initial value returned is not important. * Even though consecutive calls to MORECORE need not return contiguous addresses, it must be OK for malloc'ed chunks to span multiple regions in those cases where they do happen to be contiguous. * MORECORE need not handle negative arguments -- it may instead just return MORECORE_FAILURE when given negative arguments. Negative arguments are always multiples of pagesize. MORECORE must not misinterpret negative args as large positive unsigned args. You can suppress all such calls from even occurring by defining MORECORE_CANNOT_TRIM, There is some variation across systems about the type of the argument to sbrk/MORECORE. If size_t is unsigned, then it cannot actually be size_t, because sbrk supports negative args, so it is normally the signed type of the same width as size_t (sometimes declared as "intptr_t", and sometimes "ptrdiff_t"). It doesn't much matter though. Internally, we use "long" as arguments, which should work across all reasonable possibilities. Additionally, if MORECORE ever returns failure for a positive request, and HAVE_MMAP is true, then mmap is used as a noncontiguous system allocator. This is a useful backup strategy for systems with holes in address spaces -- in this case sbrk cannot contiguously expand the heap, but mmap may be able to map noncontiguous space. If you'd like mmap to ALWAYS be used, you can define MORECORE to be a function that always returns MORECORE_FAILURE. Malloc only has limited ability to detect failures of MORECORE to supply contiguous space when it says it can. In particular, multithreaded programs that do not use locks may result in rece conditions across calls to MORECORE that result in gaps that cannot be detected as such, and subsequent corruption. If you are using this malloc with something other than sbrk (or its emulation) to supply memory regions, you probably want to set MORECORE_CONTIGUOUS as false. As an example, here is a custom allocator kindly contributed for pre-OSX macOS. It uses virtually but not necessarily physically contiguous non-paged memory (locked in, present and won't get swapped out). You can use it by uncommenting this section, adding some #includes, and setting up the appropriate defines above: #define MORECORE osMoreCore #define MORECORE_CONTIGUOUS 0 There is also a shutdown routine that should somehow be called for cleanup upon program exit. #define MAX_POOL_ENTRIES 100 #define MINIMUM_MORECORE_SIZE (64 * 1024) static int next_os_pool; void *our_os_pools[MAX_POOL_ENTRIES]; void *osMoreCore(int size) { void *ptr = 0; static void *sbrk_top = 0; if (size > 0) { if (size < MINIMUM_MORECORE_SIZE) size = MINIMUM_MORECORE_SIZE; if (CurrentExecutionLevel() == kTaskLevel) ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0); if (ptr == 0) { return (void *) MORECORE_FAILURE; } // save ptrs so they can be freed during cleanup our_os_pools[next_os_pool] = ptr; next_os_pool++; ptr = (void *) ((((CHUNK_SIZE_T) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK); sbrk_top = (char *) ptr + size; return ptr; } else if (size < 0) { // we don't currently support shrink behavior return (void *) MORECORE_FAILURE; } else { return sbrk_top; } } // cleanup any allocated memory pools // called as last thing before shutting down driver void osCleanupMem(void) { void **ptr; for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++) if (*ptr) { PoolDeallocate(*ptr); *ptr = 0; } } */ /* -------------------------------------------------------------- Emulation of sbrk for win32. Donated by J. Walter . For additional information about this code, and malloc on Win32, see http://www.genesys-e.de/jwalter/ */ #ifdef WIN32 #ifdef _DEBUG /* #define TRACE */ #endif /* Support for USE_MALLOC_LOCK */ #ifdef USE_MALLOC_LOCK /* Wait for spin lock */ static int slwait (int *sl) { while (InterlockedCompareExchange ((void **) sl, (void *) 1, (void *) 0) != 0) Sleep (0); return 0; } /* Release spin lock */ static int slrelease (int *sl) { InterlockedExchange (sl, 0); return 0; } #ifdef NEEDED /* Spin lock for emulation code */ static int g_sl; #endif #endif /* USE_MALLOC_LOCK */ /* getpagesize for windows */ static long getpagesize (void) { static long g_pagesize = 0; if (! g_pagesize) { SYSTEM_INFO system_info; GetSystemInfo (&system_info); g_pagesize = system_info.dwPageSize; } return g_pagesize; } static long getregionsize (void) { static long g_regionsize = 0; if (! g_regionsize) { SYSTEM_INFO system_info; GetSystemInfo (&system_info); g_regionsize = system_info.dwAllocationGranularity; } return g_regionsize; } /* A region list entry */ typedef struct _region_list_entry { void *top_allocated; void *top_committed; void *top_reserved; long reserve_size; struct _region_list_entry *previous; } region_list_entry; /* Allocate and link a region entry in the region list */ static int region_list_append (region_list_entry **last, void *base_reserved, long reserve_size) { region_list_entry *next = HeapAlloc (GetProcessHeap (), 0, sizeof (region_list_entry)); if (! next) return FALSE; next->top_allocated = (char *) base_reserved; next->top_committed = (char *) base_reserved; next->top_reserved = (char *) base_reserved + reserve_size; next->reserve_size = reserve_size; next->previous = *last; *last = next; return TRUE; } /* Free and unlink the last region entry from the region list */ static int region_list_remove (region_list_entry **last) { region_list_entry *previous = (*last)->previous; if (! HeapFree (GetProcessHeap (), sizeof (region_list_entry), *last)) return FALSE; *last = previous; return TRUE; } #define CEIL(size,to) (((size)+(to)-1)&~((to)-1)) #define FLOOR(size,to) ((size)&~((to)-1)) #define SBRK_SCALE 0 /* #define SBRK_SCALE 1 */ /* #define SBRK_SCALE 2 */ /* #define SBRK_SCALE 4 */ /* sbrk for windows */ static void *sbrk (long size) { static long g_pagesize, g_my_pagesize; static long g_regionsize, g_my_regionsize; static region_list_entry *g_last; void *result = (void *) MORECORE_FAILURE; #ifdef TRACE printf ("sbrk %d\n", size); #endif #if defined (USE_MALLOC_LOCK) && defined (NEEDED) /* Wait for spin lock */ slwait (&g_sl); #endif /* First time initialization */ if (! g_pagesize) { g_pagesize = getpagesize (); g_my_pagesize = g_pagesize << SBRK_SCALE; } if (! g_regionsize) { g_regionsize = getregionsize (); g_my_regionsize = g_regionsize << SBRK_SCALE; } if (! g_last) { if (! region_list_append (&g_last, 0, 0)) goto sbrk_exit; } /* Assert invariants */ assert (g_last); assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_allocated && g_last->top_allocated <= g_last->top_committed); assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_committed && g_last->top_committed <= g_last->top_reserved && (unsigned) g_last->top_committed % g_pagesize == 0); assert ((unsigned) g_last->top_reserved % g_regionsize == 0); assert ((unsigned) g_last->reserve_size % g_regionsize == 0); /* Allocation requested? */ if (size >= 0) { /* Allocation size is the requested size */ long allocate_size = size; /* Compute the size to commit */ long to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed; /* Do we reach the commit limit? */ if (to_commit > 0) { /* Round size to commit */ long commit_size = CEIL (to_commit, g_my_pagesize); /* Compute the size to reserve */ long to_reserve = (char *) g_last->top_committed + commit_size - (char *) g_last->top_reserved; /* Do we reach the reserve limit? */ if (to_reserve > 0) { /* Compute the remaining size to commit in the current region */ long remaining_commit_size = (char *) g_last->top_reserved - (char *) g_last->top_committed; if (remaining_commit_size > 0) { /* Assert preconditions */ assert ((unsigned) g_last->top_committed % g_pagesize == 0); assert (0 < remaining_commit_size && remaining_commit_size % g_pagesize == 0); { /* Commit this */ void *base_committed = VirtualAlloc (g_last->top_committed, remaining_commit_size, MEM_COMMIT, PAGE_READWRITE); /* Check returned pointer for consistency */ if (base_committed != g_last->top_committed) goto sbrk_exit; /* Assert postconditions */ assert ((unsigned) base_committed % g_pagesize == 0); #ifdef TRACE printf ("Commit %p %d\n", base_committed, remaining_commit_size); #endif /* Adjust the regions commit top */ g_last->top_committed = (char *) base_committed + remaining_commit_size; } } { /* Now we are going to search and reserve. */ int contiguous = -1; int found = FALSE; MEMORY_BASIC_INFORMATION memory_info; void *base_reserved; long reserve_size; do { /* Assume contiguous memory */ contiguous = TRUE; /* Round size to reserve */ reserve_size = CEIL (to_reserve, g_my_regionsize); /* Start with the current region's top */ memory_info.BaseAddress = g_last->top_reserved; /* Assert preconditions */ assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0); assert (0 < reserve_size && reserve_size % g_regionsize == 0); while (VirtualQuery (memory_info.BaseAddress, &memory_info, sizeof (memory_info))) { /* Assert postconditions */ assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0); #ifdef TRACE printf ("Query %p %d %s\n", memory_info.BaseAddress, memory_info.RegionSize, memory_info.State == MEM_FREE ? "FREE": (memory_info.State == MEM_RESERVE ? "RESERVED": (memory_info.State == MEM_COMMIT ? "COMMITTED": "?"))); #endif /* Region is free, well aligned and big enough: we are done */ if (memory_info.State == MEM_FREE && (unsigned) memory_info.BaseAddress % g_regionsize == 0 && memory_info.RegionSize >= (unsigned) reserve_size) { found = TRUE; break; } /* From now on we can't get contiguous memory! */ contiguous = FALSE; /* Recompute size to reserve */ reserve_size = CEIL (allocate_size, g_my_regionsize); memory_info.BaseAddress = (char *) memory_info.BaseAddress + memory_info.RegionSize; /* Assert preconditions */ assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0); assert (0 < reserve_size && reserve_size % g_regionsize == 0); } /* Search failed? */ if (! found) goto sbrk_exit; /* Assert preconditions */ assert ((unsigned) memory_info.BaseAddress % g_regionsize == 0); assert (0 < reserve_size && reserve_size % g_regionsize == 0); /* Try to reserve this */ base_reserved = VirtualAlloc (memory_info.BaseAddress, reserve_size, MEM_RESERVE, PAGE_NOACCESS); if (! base_reserved) { int rc = GetLastError (); if (rc != ERROR_INVALID_ADDRESS) goto sbrk_exit; } /* A null pointer signals (hopefully) a race condition with another thread. */ /* In this case, we try again. */ } while (! base_reserved); /* Check returned pointer for consistency */ if (memory_info.BaseAddress && base_reserved != memory_info.BaseAddress) goto sbrk_exit; /* Assert postconditions */ assert ((unsigned) base_reserved % g_regionsize == 0); #ifdef TRACE printf ("Reserve %p %d\n", base_reserved, reserve_size); #endif /* Did we get contiguous memory? */ if (contiguous) { long start_size = (char *) g_last->top_committed - (char *) g_last->top_allocated; /* Adjust allocation size */ allocate_size -= start_size; /* Adjust the regions allocation top */ g_last->top_allocated = g_last->top_committed; /* Recompute the size to commit */ to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed; /* Round size to commit */ commit_size = CEIL (to_commit, g_my_pagesize); } /* Append the new region to the list */ if (! region_list_append (&g_last, base_reserved, reserve_size)) goto sbrk_exit; /* Didn't we get contiguous memory? */ if (! contiguous) { /* Recompute the size to commit */ to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed; /* Round size to commit */ commit_size = CEIL (to_commit, g_my_pagesize); } } } /* Assert preconditions */ assert ((unsigned) g_last->top_committed % g_pagesize == 0); assert (0 < commit_size && commit_size % g_pagesize == 0); { /* Commit this */ void *base_committed = VirtualAlloc (g_last->top_committed, commit_size, MEM_COMMIT, PAGE_READWRITE); /* Check returned pointer for consistency */ if (base_committed != g_last->top_committed) goto sbrk_exit; /* Assert postconditions */ assert ((unsigned) base_committed % g_pagesize == 0); #ifdef TRACE printf ("Commit %p %d\n", base_committed, commit_size); #endif /* Adjust the regions commit top */ g_last->top_committed = (char *) base_committed + commit_size; } } /* Adjust the regions allocation top */ g_last->top_allocated = (char *) g_last->top_allocated + allocate_size; result = (char *) g_last->top_allocated - size; /* Deallocation requested? */ } else if (size < 0) { long deallocate_size = - size; /* As long as we have a region to release */ while ((char *) g_last->top_allocated - deallocate_size < (char *) g_last->top_reserved - g_last->reserve_size) { /* Get the size to release */ long release_size = g_last->reserve_size; /* Get the base address */ void *base_reserved = (char *) g_last->top_reserved - release_size; /* Assert preconditions */ assert ((unsigned) base_reserved % g_regionsize == 0); assert (0 < release_size && release_size % g_regionsize == 0); { /* Release this */ int rc = VirtualFree (base_reserved, 0, MEM_RELEASE); /* Check returned code for consistency */ if (! rc) goto sbrk_exit; #ifdef TRACE printf ("Release %p %d\n", base_reserved, release_size); #endif } /* Adjust deallocation size */ deallocate_size -= (char *) g_last->top_allocated - (char *) base_reserved; /* Remove the old region from the list */ if (! region_list_remove (&g_last)) goto sbrk_exit; } { /* Compute the size to decommit */ long to_decommit = (char *) g_last->top_committed - ((char *) g_last->top_allocated - deallocate_size); if (to_decommit >= g_my_pagesize) { /* Compute the size to decommit */ long decommit_size = FLOOR (to_decommit, g_my_pagesize); /* Compute the base address */ void *base_committed = (char *) g_last->top_committed - decommit_size; /* Assert preconditions */ assert ((unsigned) base_committed % g_pagesize == 0); assert (0 < decommit_size && decommit_size % g_pagesize == 0); { /* Decommit this */ int rc = VirtualFree ((char *) base_committed, decommit_size, MEM_DECOMMIT); /* Check returned code for consistency */ if (! rc) goto sbrk_exit; #ifdef TRACE printf ("Decommit %p %d\n", base_committed, decommit_size); #endif } /* Adjust deallocation size and regions commit and allocate top */ deallocate_size -= (char *) g_last->top_allocated - (char *) base_committed; g_last->top_committed = base_committed; g_last->top_allocated = base_committed; } } /* Adjust regions allocate top */ g_last->top_allocated = (char *) g_last->top_allocated - deallocate_size; /* Check for underflow */ if ((char *) g_last->top_reserved - g_last->reserve_size > (char *) g_last->top_allocated || g_last->top_allocated > g_last->top_committed) { /* Adjust regions allocate top */ g_last->top_allocated = (char *) g_last->top_reserved - g_last->reserve_size; goto sbrk_exit; } result = g_last->top_allocated; } /* Assert invariants */ assert (g_last); assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_allocated && g_last->top_allocated <= g_last->top_committed); assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_committed && g_last->top_committed <= g_last->top_reserved && (unsigned) g_last->top_committed % g_pagesize == 0); assert ((unsigned) g_last->top_reserved % g_regionsize == 0); assert ((unsigned) g_last->reserve_size % g_regionsize == 0); sbrk_exit: #if defined (USE_MALLOC_LOCK) && defined (NEEDED) /* Release spin lock */ slrelease (&g_sl); #endif return result; } /* mmap for windows */ static void *mmap (void *ptr, long size, long prot, long type, long handle, long arg) { static long g_pagesize; static long g_regionsize; #ifdef TRACE printf ("mmap %d\n", size); #endif #if defined (USE_MALLOC_LOCK) && defined (NEEDED) /* Wait for spin lock */ slwait (&g_sl); #endif /* First time initialization */ if (! g_pagesize) g_pagesize = getpagesize (); if (! g_regionsize) g_regionsize = getregionsize (); /* Assert preconditions */ assert ((unsigned) ptr % g_regionsize == 0); assert (size % g_pagesize == 0); /* Allocate this */ ptr = VirtualAlloc (ptr, size, MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN, PAGE_READWRITE); if (! ptr) { ptr = (void *) MORECORE_FAILURE; goto mmap_exit; } /* Assert postconditions */ assert ((unsigned) ptr % g_regionsize == 0); #ifdef TRACE printf ("Commit %p %d\n", ptr, size); #endif mmap_exit: #if defined (USE_MALLOC_LOCK) && defined (NEEDED) /* Release spin lock */ slrelease (&g_sl); #endif return ptr; } /* munmap for windows */ static long munmap (void *ptr, long size) { static long g_pagesize; static long g_regionsize; int rc = MUNMAP_FAILURE; #ifdef TRACE printf ("munmap %p %d\n", ptr, size); #endif #if defined (USE_MALLOC_LOCK) && defined (NEEDED) /* Wait for spin lock */ slwait (&g_sl); #endif /* First time initialization */ if (! g_pagesize) g_pagesize = getpagesize (); if (! g_regionsize) g_regionsize = getregionsize (); /* Assert preconditions */ assert ((unsigned) ptr % g_regionsize == 0); assert (size % g_pagesize == 0); /* Free this */ if (! VirtualFree (ptr, 0, MEM_RELEASE)) goto munmap_exit; rc = 0; #ifdef TRACE printf ("Release %p %d\n", ptr, size); #endif munmap_exit: #if defined (USE_MALLOC_LOCK) && defined (NEEDED) /* Release spin lock */ slrelease (&g_sl); #endif return rc; } static void vminfo (CHUNK_SIZE_T *free, CHUNK_SIZE_T *reserved, CHUNK_SIZE_T *committed) { MEMORY_BASIC_INFORMATION memory_info; memory_info.BaseAddress = 0; *free = *reserved = *committed = 0; while (VirtualQuery (memory_info.BaseAddress, &memory_info, sizeof (memory_info))) { switch (memory_info.State) { case MEM_FREE: *free += memory_info.RegionSize; break; case MEM_RESERVE: *reserved += memory_info.RegionSize; break; case MEM_COMMIT: *committed += memory_info.RegionSize; break; } memory_info.BaseAddress = (char *) memory_info.BaseAddress + memory_info.RegionSize; } } static int cpuinfo (int whole, CHUNK_SIZE_T *kernel, CHUNK_SIZE_T *user) { if (whole) { __int64 creation64, exit64, kernel64, user64; int rc = GetProcessTimes (GetCurrentProcess (), (FILETIME *) &creation64, (FILETIME *) &exit64, (FILETIME *) &kernel64, (FILETIME *) &user64); if (! rc) { *kernel = 0; *user = 0; return FALSE; } *kernel = (CHUNK_SIZE_T) (kernel64 / 10000); *user = (CHUNK_SIZE_T) (user64 / 10000); return TRUE; } else { __int64 creation64, exit64, kernel64, user64; int rc = GetThreadTimes (GetCurrentThread (), (FILETIME *) &creation64, (FILETIME *) &exit64, (FILETIME *) &kernel64, (FILETIME *) &user64); if (! rc) { *kernel = 0; *user = 0; return FALSE; } *kernel = (CHUNK_SIZE_T) (kernel64 / 10000); *user = (CHUNK_SIZE_T) (user64 / 10000); return TRUE; } } #endif /* WIN32 */ /* ------------------------------------------------------------ History: V2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee) * Fix malloc_state bitmap array misdeclaration V2.7.1 Thu Jul 25 10:58:03 2002 Doug Lea (dl at gee) * Allow tuning of FIRST_SORTED_BIN_SIZE * Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte. * Better detection and support for non-contiguousness of MORECORE. Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger * Bypass most of malloc if no frees. Thanks To Emery Berger. * Fix freeing of old top non-contiguous chunk im sysmalloc. * Raised default trim and map thresholds to 256K. * Fix mmap-related #defines. Thanks to Lubos Lunak. * Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield. * Branch-free bin calculation * Default trim and mmap thresholds now 256K. V2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee) * Introduce independent_comalloc and independent_calloc. Thanks to Michael Pachos for motivation and help. * Make optional .h file available * Allow > 2GB requests on 32bit systems. * new WIN32 sbrk, mmap, munmap, lock code from . Thanks also to Andreas Mueller , and Anonymous. * Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for helping test this.) * memalign: check alignment arg * realloc: don't try to shift chunks backwards, since this leads to more fragmentation in some programs and doesn't seem to help in any others. * Collect all cases in malloc requiring system memory into sYSMALLOc * Use mmap as backup to sbrk * Place all internal state in malloc_state * Introduce fastbins (although similar to 2.5.1) * Many minor tunings and cosmetic improvements * Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK * Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS Thanks to Tony E. Bennett and others. * Include errno.h to support default failure action. V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee) * return null for negative arguments * Added Several WIN32 cleanups from Martin C. Fong * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h' (e.g. WIN32 platforms) * Cleanup header file inclusion for WIN32 platforms * Cleanup code to avoid Microsoft Visual C++ compiler complaints * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing memory allocation routines * Set 'malloc_getpagesize' for WIN32 platforms (needs more work) * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to usage of 'assert' in non-WIN32 code * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to avoid infinite loop * Always call 'fREe()' rather than 'free()' V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee) * Fixed ordering problem with boundary-stamping V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee) * Added pvalloc, as recommended by H.J. Liu * Added 64bit pointer support mainly from Wolfram Gloger * Added anonymously donated WIN32 sbrk emulation * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen * malloc_extend_top: fix mask error that caused wastage after foreign sbrks * Add linux mremap support code from HJ Liu V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee) * Integrated most documentation with the code. * Add support for mmap, with help from Wolfram Gloger (Gloger@lrz.uni-muenchen.de). * Use last_remainder in more cases. * Pack bins using idea from colin@nyx10.cs.du.edu * Use ordered bins instead of best-fit threshhold * Eliminate block-local decls to simplify tracing and debugging. * Support another case of realloc via move into top * Fix error occuring when initial sbrk_base not word-aligned. * Rely on page size for units instead of SBRK_UNIT to avoid surprises about sbrk alignment conventions. * Add mallinfo, mallopt. Thanks to Raymond Nijssen (raymond@es.ele.tue.nl) for the suggestion. * Add `pad' argument to malloc_trim and top_pad mallopt parameter. * More precautions for cases where other routines call sbrk, courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de). * Added macros etc., allowing use in linux libc from H.J. Lu (hjl@gnu.ai.mit.edu) * Inverted this history list V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee) * Re-tuned and fixed to behave more nicely with V2.6.0 changes. * Removed all preallocation code since under current scheme the work required to undo bad preallocations exceeds the work saved in good cases for most test programs. * No longer use return list or unconsolidated bins since no scheme using them consistently outperforms those that don't given above changes. * Use best fit for very large chunks to prevent some worst-cases. * Added some support for debugging V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee) * Removed footers when chunks are in use. Thanks to Paul Wilson (wilson@cs.texas.edu) for the suggestion. V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee) * Added malloc_trim, with help from Wolfram Gloger (wmglo@Dent.MED.Uni-Muenchen.DE). V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g) V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g) * realloc: try to expand in both directions * malloc: swap order of clean-bin strategy; * realloc: only conditionally expand backwards * Try not to scavenge used bins * Use bin counts as a guide to preallocation * Occasionally bin return list chunks in first scan * Add a few optimizations from colin@nyx10.cs.du.edu V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g) * faster bin computation & slightly different binning * merged all consolidations to one part of malloc proper (eliminating old malloc_find_space & malloc_clean_bin) * Scan 2 returns chunks (not just 1) * Propagate failure in realloc if malloc returns 0 * Add stuff to allow compilation on non-ANSI compilers from kpv@research.att.com V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu) * removed potential for odd address access in prev_chunk * removed dependency on getpagesize.h * misc cosmetics and a bit more internal documentation * anticosmetics: mangled names in macros to evade debugger strangeness * tested on sparc, hp-700, dec-mips, rs6000 with gcc & native cc (hp, dec only) allowing Detlefs & Zorn comparison study (in SIGPLAN Notices.) Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu) * Based loosely on libg++-1.2X malloc. (It retains some of the overall structure of old version, but most details differ.) */