| /* Malloc implementation for multiple threads without lock contention. |
| Copyright (C) 2001,2002,2003,2004,2005,2006,2007,2009,2010 |
| Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Wolfram Gloger <wg@malloc.de>, 2001. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public License as |
| published by the Free Software Foundation; either version 2.1 of the |
| License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; see the file COPYING.LIB. If not, |
| write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include <stdbool.h> |
| |
| /* Compile-time constants. */ |
| |
| #define HEAP_MIN_SIZE (32*1024) |
| #ifndef HEAP_MAX_SIZE |
| # ifdef DEFAULT_MMAP_THRESHOLD_MAX |
| # define HEAP_MAX_SIZE (2 * DEFAULT_MMAP_THRESHOLD_MAX) |
| # else |
| # define HEAP_MAX_SIZE (1024*1024) /* must be a power of two */ |
| # endif |
| #endif |
| |
| /* HEAP_MIN_SIZE and HEAP_MAX_SIZE limit the size of mmap()ed heaps |
| that are dynamically created for multi-threaded programs. The |
| maximum size must be a power of two, for fast determination of |
| which heap belongs to a chunk. It should be much larger than the |
| mmap threshold, so that requests with a size just below that |
| threshold can be fulfilled without creating too many heaps. */ |
| |
| |
| #ifndef THREAD_STATS |
| #define THREAD_STATS 0 |
| #endif |
| |
| /* If THREAD_STATS is non-zero, some statistics on mutex locking are |
| computed. */ |
| |
| /***************************************************************************/ |
| |
| #define top(ar_ptr) ((ar_ptr)->top) |
| |
| /* A heap is a single contiguous memory region holding (coalesceable) |
| malloc_chunks. It is allocated with mmap() and always starts at an |
| address aligned to HEAP_MAX_SIZE. Not used unless compiling with |
| USE_ARENAS. */ |
| |
| typedef struct _heap_info { |
| mstate ar_ptr; /* Arena for this heap. */ |
| struct _heap_info *prev; /* Previous heap. */ |
| size_t size; /* Current size in bytes. */ |
| size_t mprotect_size; /* Size in bytes that has been mprotected |
| PROT_READ|PROT_WRITE. */ |
| /* Make sure the following data is properly aligned, particularly |
| that sizeof (heap_info) + 2 * SIZE_SZ is a multiple of |
| MALLOC_ALIGNMENT. */ |
| char pad[-6 * SIZE_SZ & MALLOC_ALIGN_MASK]; |
| } heap_info; |
| |
| /* Get a compile-time error if the heap_info padding is not correct |
| to make alignment work as expected in sYSMALLOc. */ |
| extern int sanity_check_heap_info_alignment[(sizeof (heap_info) |
| + 2 * SIZE_SZ) % MALLOC_ALIGNMENT |
| ? -1 : 1]; |
| |
| /* Thread specific data */ |
| |
| static tsd_key_t arena_key; |
| static mutex_t list_lock; |
| #ifdef PER_THREAD |
| static size_t narenas; |
| static mstate free_list; |
| #endif |
| |
| #if THREAD_STATS |
| static int stat_n_heaps; |
| #define THREAD_STAT(x) x |
| #else |
| #define THREAD_STAT(x) do ; while(0) |
| #endif |
| |
| /* Mapped memory in non-main arenas (reliable only for NO_THREADS). */ |
| static unsigned long arena_mem; |
| |
| /* Already initialized? */ |
| int __malloc_initialized = -1; |
| |
| /**************************************************************************/ |
| |
| #if USE_ARENAS |
| |
| /* arena_get() acquires an arena and locks the corresponding mutex. |
| First, try the one last locked successfully by this thread. (This |
| is the common case and handled with a macro for speed.) Then, loop |
| once over the circularly linked list of arenas. If no arena is |
| readily available, create a new one. In this latter case, `size' |
| is just a hint as to how much memory will be required immediately |
| in the new arena. */ |
| |
| #define arena_get(ptr, size) do { \ |
| arena_lookup(ptr); \ |
| arena_lock(ptr, size); \ |
| } while(0) |
| |
| #define arena_lookup(ptr) do { \ |
| Void_t *vptr = NULL; \ |
| ptr = (mstate)tsd_getspecific(arena_key, vptr); \ |
| } while(0) |
| |
| #ifdef PER_THREAD |
| #define arena_lock(ptr, size) do { \ |
| if(ptr) \ |
| (void)mutex_lock(&ptr->mutex); \ |
| else \ |
| ptr = arena_get2(ptr, (size)); \ |
| } while(0) |
| #else |
| #define arena_lock(ptr, size) do { \ |
| if(ptr && !mutex_trylock(&ptr->mutex)) { \ |
| THREAD_STAT(++(ptr->stat_lock_direct)); \ |
| } else \ |
| ptr = arena_get2(ptr, (size)); \ |
| } while(0) |
| #endif |
| |
| /* find the heap and corresponding arena for a given ptr */ |
| |
| #define heap_for_ptr(ptr) \ |
| ((heap_info *)((unsigned long)(ptr) & ~(HEAP_MAX_SIZE-1))) |
| #define arena_for_chunk(ptr) \ |
| (chunk_non_main_arena(ptr) ? heap_for_ptr(ptr)->ar_ptr : &main_arena) |
| |
| #else /* !USE_ARENAS */ |
| |
| /* There is only one arena, main_arena. */ |
| |
| #if THREAD_STATS |
| #define arena_get(ar_ptr, sz) do { \ |
| ar_ptr = &main_arena; \ |
| if(!mutex_trylock(&ar_ptr->mutex)) \ |
| ++(ar_ptr->stat_lock_direct); \ |
| else { \ |
| (void)mutex_lock(&ar_ptr->mutex); \ |
| ++(ar_ptr->stat_lock_wait); \ |
| } \ |
| } while(0) |
| #else |
| #define arena_get(ar_ptr, sz) do { \ |
| ar_ptr = &main_arena; \ |
| (void)mutex_lock(&ar_ptr->mutex); \ |
| } while(0) |
| #endif |
| #define arena_for_chunk(ptr) (&main_arena) |
| |
| #endif /* USE_ARENAS */ |
| |
| /**************************************************************************/ |
| |
| #ifndef NO_THREADS |
| |
| /* atfork support. */ |
| |
| static __malloc_ptr_t (*save_malloc_hook) (size_t __size, |
| __const __malloc_ptr_t); |
| # if !defined _LIBC || (defined SHARED && !USE___THREAD) |
| static __malloc_ptr_t (*save_memalign_hook) (size_t __align, size_t __size, |
| __const __malloc_ptr_t); |
| # endif |
| static void (*save_free_hook) (__malloc_ptr_t __ptr, |
| __const __malloc_ptr_t); |
| static Void_t* save_arena; |
| |
| #ifdef ATFORK_MEM |
| ATFORK_MEM; |
| #endif |
| |
| /* Magic value for the thread-specific arena pointer when |
| malloc_atfork() is in use. */ |
| |
| #define ATFORK_ARENA_PTR ((Void_t*)-1) |
| |
| /* The following hooks are used while the `atfork' handling mechanism |
| is active. */ |
| |
| static Void_t* |
| malloc_atfork(size_t sz, const Void_t *caller) |
| { |
| Void_t *vptr = NULL; |
| Void_t *victim; |
| |
| tsd_getspecific(arena_key, vptr); |
| if(vptr == ATFORK_ARENA_PTR) { |
| /* We are the only thread that may allocate at all. */ |
| if(save_malloc_hook != malloc_check) { |
| return _int_malloc(&main_arena, sz); |
| } else { |
| if(top_check()<0) |
| return 0; |
| victim = _int_malloc(&main_arena, sz+1); |
| return mem2mem_check(victim, sz); |
| } |
| } else { |
| /* Suspend the thread until the `atfork' handlers have completed. |
| By that time, the hooks will have been reset as well, so that |
| mALLOc() can be used again. */ |
| (void)mutex_lock(&list_lock); |
| (void)mutex_unlock(&list_lock); |
| return public_mALLOc(sz); |
| } |
| } |
| |
| static void |
| free_atfork(Void_t* mem, const Void_t *caller) |
| { |
| Void_t *vptr = NULL; |
| mstate ar_ptr; |
| mchunkptr p; /* chunk corresponding to mem */ |
| |
| if (mem == 0) /* free(0) has no effect */ |
| return; |
| |
| p = mem2chunk(mem); /* do not bother to replicate free_check here */ |
| |
| #if HAVE_MMAP |
| if (chunk_is_mmapped(p)) /* release mmapped memory. */ |
| { |
| munmap_chunk(p); |
| return; |
| } |
| #endif |
| |
| #ifdef ATOMIC_FASTBINS |
| ar_ptr = arena_for_chunk(p); |
| tsd_getspecific(arena_key, vptr); |
| _int_free(ar_ptr, p, vptr == ATFORK_ARENA_PTR); |
| #else |
| ar_ptr = arena_for_chunk(p); |
| tsd_getspecific(arena_key, vptr); |
| if(vptr != ATFORK_ARENA_PTR) |
| (void)mutex_lock(&ar_ptr->mutex); |
| _int_free(ar_ptr, p); |
| if(vptr != ATFORK_ARENA_PTR) |
| (void)mutex_unlock(&ar_ptr->mutex); |
| #endif |
| } |
| |
| |
| /* Counter for number of times the list is locked by the same thread. */ |
| static unsigned int atfork_recursive_cntr; |
| |
| /* The following two functions are registered via thread_atfork() to |
| make sure that the mutexes remain in a consistent state in the |
| fork()ed version of a thread. Also adapt the malloc and free hooks |
| temporarily, because the `atfork' handler mechanism may use |
| malloc/free internally (e.g. in LinuxThreads). */ |
| |
| static void |
| ptmalloc_lock_all (void) |
| { |
| mstate ar_ptr; |
| |
| if(__malloc_initialized < 1) |
| return; |
| if (mutex_trylock(&list_lock)) |
| { |
| Void_t *my_arena; |
| tsd_getspecific(arena_key, my_arena); |
| if (my_arena == ATFORK_ARENA_PTR) |
| /* This is the same thread which already locks the global list. |
| Just bump the counter. */ |
| goto out; |
| |
| /* This thread has to wait its turn. */ |
| (void)mutex_lock(&list_lock); |
| } |
| for(ar_ptr = &main_arena;;) { |
| (void)mutex_lock(&ar_ptr->mutex); |
| ar_ptr = ar_ptr->next; |
| if(ar_ptr == &main_arena) break; |
| } |
| save_malloc_hook = __malloc_hook; |
| save_free_hook = __free_hook; |
| __malloc_hook = malloc_atfork; |
| __free_hook = free_atfork; |
| /* Only the current thread may perform malloc/free calls now. */ |
| tsd_getspecific(arena_key, save_arena); |
| tsd_setspecific(arena_key, ATFORK_ARENA_PTR); |
| out: |
| ++atfork_recursive_cntr; |
| } |
| |
| static void |
| ptmalloc_unlock_all (void) |
| { |
| mstate ar_ptr; |
| |
| if(__malloc_initialized < 1) |
| return; |
| if (--atfork_recursive_cntr != 0) |
| return; |
| tsd_setspecific(arena_key, save_arena); |
| __malloc_hook = save_malloc_hook; |
| __free_hook = save_free_hook; |
| for(ar_ptr = &main_arena;;) { |
| (void)mutex_unlock(&ar_ptr->mutex); |
| ar_ptr = ar_ptr->next; |
| if(ar_ptr == &main_arena) break; |
| } |
| (void)mutex_unlock(&list_lock); |
| } |
| |
| #ifdef __linux__ |
| |
| /* In NPTL, unlocking a mutex in the child process after a |
| fork() is currently unsafe, whereas re-initializing it is safe and |
| does not leak resources. Therefore, a special atfork handler is |
| installed for the child. */ |
| |
| static void |
| ptmalloc_unlock_all2 (void) |
| { |
| mstate ar_ptr; |
| |
| if(__malloc_initialized < 1) |
| return; |
| #if defined _LIBC || defined MALLOC_HOOKS |
| tsd_setspecific(arena_key, save_arena); |
| __malloc_hook = save_malloc_hook; |
| __free_hook = save_free_hook; |
| #endif |
| #ifdef PER_THREAD |
| free_list = NULL; |
| #endif |
| for(ar_ptr = &main_arena;;) { |
| mutex_init(&ar_ptr->mutex); |
| #ifdef PER_THREAD |
| if (ar_ptr != save_arena) { |
| ar_ptr->next_free = free_list; |
| free_list = ar_ptr; |
| } |
| #endif |
| ar_ptr = ar_ptr->next; |
| if(ar_ptr == &main_arena) break; |
| } |
| mutex_init(&list_lock); |
| atfork_recursive_cntr = 0; |
| } |
| |
| #else |
| |
| #define ptmalloc_unlock_all2 ptmalloc_unlock_all |
| |
| #endif |
| |
| #endif /* !defined NO_THREADS */ |
| |
| /* Initialization routine. */ |
| #ifdef _LIBC |
| #include <string.h> |
| extern char **_environ; |
| |
| static char * |
| internal_function |
| next_env_entry (char ***position) |
| { |
| char **current = *position; |
| char *result = NULL; |
| |
| while (*current != NULL) |
| { |
| if (__builtin_expect ((*current)[0] == 'M', 0) |
| && (*current)[1] == 'A' |
| && (*current)[2] == 'L' |
| && (*current)[3] == 'L' |
| && (*current)[4] == 'O' |
| && (*current)[5] == 'C' |
| && (*current)[6] == '_') |
| { |
| result = &(*current)[7]; |
| |
| /* Save current position for next visit. */ |
| *position = ++current; |
| |
| break; |
| } |
| |
| ++current; |
| } |
| |
| return result; |
| } |
| #endif /* _LIBC */ |
| |
| /* Set up basic state so that _int_malloc et al can work. */ |
| static void |
| ptmalloc_init_minimal (void) |
| { |
| #if DEFAULT_TOP_PAD != 0 |
| mp_.top_pad = DEFAULT_TOP_PAD; |
| #endif |
| mp_.n_mmaps_max = DEFAULT_MMAP_MAX; |
| mp_.mmap_threshold = DEFAULT_MMAP_THRESHOLD; |
| mp_.trim_threshold = DEFAULT_TRIM_THRESHOLD; |
| mp_.pagesize = malloc_getpagesize; |
| #ifdef PER_THREAD |
| # define NARENAS_FROM_NCORES(n) ((n) * (sizeof(long) == 4 ? 2 : 8)) |
| mp_.arena_test = NARENAS_FROM_NCORES (1); |
| narenas = 1; |
| #endif |
| } |
| |
| |
| #ifdef _LIBC |
| # ifdef SHARED |
| static void * |
| __failing_morecore (ptrdiff_t d) |
| { |
| return (void *) MORECORE_FAILURE; |
| } |
| |
| extern struct dl_open_hook *_dl_open_hook; |
| libc_hidden_proto (_dl_open_hook); |
| # endif |
| |
| # if defined SHARED && !USE___THREAD |
| /* This is called by __pthread_initialize_minimal when it needs to use |
| malloc to set up the TLS state. We cannot do the full work of |
| ptmalloc_init (below) until __pthread_initialize_minimal has finished, |
| so it has to switch to using the special startup-time hooks while doing |
| those allocations. */ |
| void |
| __libc_malloc_pthread_startup (bool first_time) |
| { |
| if (first_time) |
| { |
| ptmalloc_init_minimal (); |
| save_malloc_hook = __malloc_hook; |
| save_memalign_hook = __memalign_hook; |
| save_free_hook = __free_hook; |
| __malloc_hook = malloc_starter; |
| __memalign_hook = memalign_starter; |
| __free_hook = free_starter; |
| } |
| else |
| { |
| __malloc_hook = save_malloc_hook; |
| __memalign_hook = save_memalign_hook; |
| __free_hook = save_free_hook; |
| } |
| } |
| # endif |
| #endif |
| |
| static void |
| ptmalloc_init (void) |
| { |
| #if __STD_C |
| const char* s; |
| #else |
| char* s; |
| #endif |
| int secure = 0; |
| |
| if(__malloc_initialized >= 0) return; |
| __malloc_initialized = 0; |
| |
| #ifdef _LIBC |
| # if defined SHARED && !USE___THREAD |
| /* ptmalloc_init_minimal may already have been called via |
| __libc_malloc_pthread_startup, above. */ |
| if (mp_.pagesize == 0) |
| # endif |
| #endif |
| ptmalloc_init_minimal(); |
| |
| #ifndef NO_THREADS |
| # if defined _LIBC |
| /* We know __pthread_initialize_minimal has already been called, |
| and that is enough. */ |
| # define NO_STARTER |
| # endif |
| # ifndef NO_STARTER |
| /* With some threads implementations, creating thread-specific data |
| or initializing a mutex may call malloc() itself. Provide a |
| simple starter version (realloc() won't work). */ |
| save_malloc_hook = __malloc_hook; |
| save_memalign_hook = __memalign_hook; |
| save_free_hook = __free_hook; |
| __malloc_hook = malloc_starter; |
| __memalign_hook = memalign_starter; |
| __free_hook = free_starter; |
| # ifdef _LIBC |
| /* Initialize the pthreads interface. */ |
| if (__pthread_initialize != NULL) |
| __pthread_initialize(); |
| # endif /* !defined _LIBC */ |
| # endif /* !defined NO_STARTER */ |
| #endif /* !defined NO_THREADS */ |
| mutex_init(&main_arena.mutex); |
| main_arena.next = &main_arena; |
| |
| #if defined _LIBC && defined SHARED |
| /* In case this libc copy is in a non-default namespace, never use brk. |
| Likewise if dlopened from statically linked program. */ |
| Dl_info di; |
| struct link_map *l; |
| |
| if (_dl_open_hook != NULL |
| || (_dl_addr (ptmalloc_init, &di, &l, NULL) != 0 |
| && l->l_ns != LM_ID_BASE)) |
| __morecore = __failing_morecore; |
| #endif |
| |
| mutex_init(&list_lock); |
| tsd_key_create(&arena_key, NULL); |
| tsd_setspecific(arena_key, (Void_t *)&main_arena); |
| thread_atfork(ptmalloc_lock_all, ptmalloc_unlock_all, ptmalloc_unlock_all2); |
| #ifndef NO_THREADS |
| # ifndef NO_STARTER |
| __malloc_hook = save_malloc_hook; |
| __memalign_hook = save_memalign_hook; |
| __free_hook = save_free_hook; |
| # else |
| # undef NO_STARTER |
| # endif |
| #endif |
| #ifdef _LIBC |
| secure = __libc_enable_secure; |
| s = NULL; |
| if (__builtin_expect (_environ != NULL, 1)) |
| { |
| char **runp = _environ; |
| char *envline; |
| |
| while (__builtin_expect ((envline = next_env_entry (&runp)) != NULL, |
| 0)) |
| { |
| size_t len = strcspn (envline, "="); |
| |
| if (envline[len] != '=') |
| /* This is a "MALLOC_" variable at the end of the string |
| without a '=' character. Ignore it since otherwise we |
| will access invalid memory below. */ |
| continue; |
| |
| switch (len) |
| { |
| case 6: |
| if (memcmp (envline, "CHECK_", 6) == 0) |
| s = &envline[7]; |
| break; |
| case 8: |
| if (! secure) |
| { |
| if (memcmp (envline, "TOP_PAD_", 8) == 0) |
| mALLOPt(M_TOP_PAD, atoi(&envline[9])); |
| else if (memcmp (envline, "PERTURB_", 8) == 0) |
| mALLOPt(M_PERTURB, atoi(&envline[9])); |
| } |
| break; |
| case 9: |
| if (! secure) |
| { |
| if (memcmp (envline, "MMAP_MAX_", 9) == 0) |
| mALLOPt(M_MMAP_MAX, atoi(&envline[10])); |
| #ifdef PER_THREAD |
| else if (memcmp (envline, "ARENA_MAX", 9) == 0) |
| mALLOPt(M_ARENA_MAX, atoi(&envline[10])); |
| #endif |
| } |
| break; |
| #ifdef PER_THREAD |
| case 10: |
| if (! secure) |
| { |
| if (memcmp (envline, "ARENA_TEST", 10) == 0) |
| mALLOPt(M_ARENA_TEST, atoi(&envline[11])); |
| } |
| break; |
| #endif |
| case 15: |
| if (! secure) |
| { |
| if (memcmp (envline, "TRIM_THRESHOLD_", 15) == 0) |
| mALLOPt(M_TRIM_THRESHOLD, atoi(&envline[16])); |
| else if (memcmp (envline, "MMAP_THRESHOLD_", 15) == 0) |
| mALLOPt(M_MMAP_THRESHOLD, atoi(&envline[16])); |
| } |
| break; |
| default: |
| break; |
| } |
| } |
| } |
| #else |
| if (! secure) |
| { |
| if((s = getenv("MALLOC_TRIM_THRESHOLD_"))) |
| mALLOPt(M_TRIM_THRESHOLD, atoi(s)); |
| if((s = getenv("MALLOC_TOP_PAD_"))) |
| mALLOPt(M_TOP_PAD, atoi(s)); |
| if((s = getenv("MALLOC_PERTURB_"))) |
| mALLOPt(M_PERTURB, atoi(s)); |
| if((s = getenv("MALLOC_MMAP_THRESHOLD_"))) |
| mALLOPt(M_MMAP_THRESHOLD, atoi(s)); |
| if((s = getenv("MALLOC_MMAP_MAX_"))) |
| mALLOPt(M_MMAP_MAX, atoi(s)); |
| } |
| s = getenv("MALLOC_CHECK_"); |
| #endif |
| if(s && s[0]) { |
| mALLOPt(M_CHECK_ACTION, (int)(s[0] - '0')); |
| if (check_action != 0) |
| __malloc_check_init(); |
| } |
| void (*hook) (void) = force_reg (__malloc_initialize_hook); |
| if (hook != NULL) |
| (*hook)(); |
| __malloc_initialized = 1; |
| } |
| |
| /* There are platforms (e.g. Hurd) with a link-time hook mechanism. */ |
| #ifdef thread_atfork_static |
| thread_atfork_static(ptmalloc_lock_all, ptmalloc_unlock_all, \ |
| ptmalloc_unlock_all2) |
| #endif |
| |
| |
| |
| /* Managing heaps and arenas (for concurrent threads) */ |
| |
| #if USE_ARENAS |
| |
| #if MALLOC_DEBUG > 1 |
| |
| /* Print the complete contents of a single heap to stderr. */ |
| |
| static void |
| #if __STD_C |
| dump_heap(heap_info *heap) |
| #else |
| dump_heap(heap) heap_info *heap; |
| #endif |
| { |
| char *ptr; |
| mchunkptr p; |
| |
| fprintf(stderr, "Heap %p, size %10lx:\n", heap, (long)heap->size); |
| ptr = (heap->ar_ptr != (mstate)(heap+1)) ? |
| (char*)(heap + 1) : (char*)(heap + 1) + sizeof(struct malloc_state); |
| p = (mchunkptr)(((unsigned long)ptr + MALLOC_ALIGN_MASK) & |
| ~MALLOC_ALIGN_MASK); |
| for(;;) { |
| fprintf(stderr, "chunk %p size %10lx", p, (long)p->size); |
| if(p == top(heap->ar_ptr)) { |
| fprintf(stderr, " (top)\n"); |
| break; |
| } else if(p->size == (0|PREV_INUSE)) { |
| fprintf(stderr, " (fence)\n"); |
| break; |
| } |
| fprintf(stderr, "\n"); |
| p = next_chunk(p); |
| } |
| } |
| |
| #endif /* MALLOC_DEBUG > 1 */ |
| |
| /* If consecutive mmap (0, HEAP_MAX_SIZE << 1, ...) calls return decreasing |
| addresses as opposed to increasing, new_heap would badly fragment the |
| address space. In that case remember the second HEAP_MAX_SIZE part |
| aligned to HEAP_MAX_SIZE from last mmap (0, HEAP_MAX_SIZE << 1, ...) |
| call (if it is already aligned) and try to reuse it next time. We need |
| no locking for it, as kernel ensures the atomicity for us - worst case |
| we'll call mmap (addr, HEAP_MAX_SIZE, ...) for some value of addr in |
| multiple threads, but only one will succeed. */ |
| static char *aligned_heap_area; |
| |
| /* Create a new heap. size is automatically rounded up to a multiple |
| of the page size. */ |
| |
| static heap_info * |
| internal_function |
| #if __STD_C |
| new_heap(size_t size, size_t top_pad) |
| #else |
| new_heap(size, top_pad) size_t size, top_pad; |
| #endif |
| { |
| size_t page_mask = malloc_getpagesize - 1; |
| char *p1, *p2; |
| unsigned long ul; |
| heap_info *h; |
| |
| if(size+top_pad < HEAP_MIN_SIZE) |
| size = HEAP_MIN_SIZE; |
| else if(size+top_pad <= HEAP_MAX_SIZE) |
| size += top_pad; |
| else if(size > HEAP_MAX_SIZE) |
| return 0; |
| else |
| size = HEAP_MAX_SIZE; |
| size = (size + page_mask) & ~page_mask; |
| |
| /* A memory region aligned to a multiple of HEAP_MAX_SIZE is needed. |
| No swap space needs to be reserved for the following large |
| mapping (on Linux, this is the case for all non-writable mappings |
| anyway). */ |
| p2 = MAP_FAILED; |
| if(aligned_heap_area) { |
| p2 = (char *)MMAP(aligned_heap_area, HEAP_MAX_SIZE, PROT_NONE, |
| MAP_PRIVATE|MAP_NORESERVE); |
| aligned_heap_area = NULL; |
| if (p2 != MAP_FAILED && ((unsigned long)p2 & (HEAP_MAX_SIZE-1))) { |
| munmap(p2, HEAP_MAX_SIZE); |
| p2 = MAP_FAILED; |
| } |
| } |
| if(p2 == MAP_FAILED) { |
| p1 = (char *)MMAP(0, HEAP_MAX_SIZE<<1, PROT_NONE, |
| MAP_PRIVATE|MAP_NORESERVE); |
| if(p1 != MAP_FAILED) { |
| p2 = (char *)(((unsigned long)p1 + (HEAP_MAX_SIZE-1)) |
| & ~(HEAP_MAX_SIZE-1)); |
| ul = p2 - p1; |
| if (ul) |
| munmap(p1, ul); |
| else |
| aligned_heap_area = p2 + HEAP_MAX_SIZE; |
| munmap(p2 + HEAP_MAX_SIZE, HEAP_MAX_SIZE - ul); |
| } else { |
| /* Try to take the chance that an allocation of only HEAP_MAX_SIZE |
| is already aligned. */ |
| p2 = (char *)MMAP(0, HEAP_MAX_SIZE, PROT_NONE, MAP_PRIVATE|MAP_NORESERVE); |
| if(p2 == MAP_FAILED) |
| return 0; |
| if((unsigned long)p2 & (HEAP_MAX_SIZE-1)) { |
| munmap(p2, HEAP_MAX_SIZE); |
| return 0; |
| } |
| } |
| } |
| if(mprotect(p2, size, PROT_READ|PROT_WRITE) != 0) { |
| munmap(p2, HEAP_MAX_SIZE); |
| return 0; |
| } |
| h = (heap_info *)p2; |
| h->size = size; |
| h->mprotect_size = size; |
| THREAD_STAT(stat_n_heaps++); |
| return h; |
| } |
| |
| /* Grow a heap. size is automatically rounded up to a |
| multiple of the page size. */ |
| |
| static int |
| #if __STD_C |
| grow_heap(heap_info *h, long diff) |
| #else |
| grow_heap(h, diff) heap_info *h; long diff; |
| #endif |
| { |
| size_t page_mask = malloc_getpagesize - 1; |
| long new_size; |
| |
| diff = (diff + page_mask) & ~page_mask; |
| new_size = (long)h->size + diff; |
| if((unsigned long) new_size > (unsigned long) HEAP_MAX_SIZE) |
| return -1; |
| if((unsigned long) new_size > h->mprotect_size) { |
| if (mprotect((char *)h + h->mprotect_size, |
| (unsigned long) new_size - h->mprotect_size, |
| PROT_READ|PROT_WRITE) != 0) |
| return -2; |
| h->mprotect_size = new_size; |
| } |
| |
| h->size = new_size; |
| return 0; |
| } |
| |
| /* Shrink a heap. */ |
| |
| static int |
| #if __STD_C |
| shrink_heap(heap_info *h, long diff) |
| #else |
| shrink_heap(h, diff) heap_info *h; long diff; |
| #endif |
| { |
| long new_size; |
| |
| new_size = (long)h->size - diff; |
| if(new_size < (long)sizeof(*h)) |
| return -1; |
| /* Try to re-map the extra heap space freshly to save memory, and |
| make it inaccessible. */ |
| #ifdef _LIBC |
| if (__builtin_expect (__libc_enable_secure, 0)) |
| #else |
| if (1) |
| #endif |
| { |
| if((char *)MMAP((char *)h + new_size, diff, PROT_NONE, |
| MAP_PRIVATE|MAP_FIXED) == (char *) MAP_FAILED) |
| return -2; |
| h->mprotect_size = new_size; |
| } |
| #ifdef _LIBC |
| else |
| madvise ((char *)h + new_size, diff, MADV_DONTNEED); |
| #endif |
| /*fprintf(stderr, "shrink %p %08lx\n", h, new_size);*/ |
| |
| h->size = new_size; |
| return 0; |
| } |
| |
| /* Delete a heap. */ |
| |
| #define delete_heap(heap) \ |
| do { \ |
| if ((char *)(heap) + HEAP_MAX_SIZE == aligned_heap_area) \ |
| aligned_heap_area = NULL; \ |
| munmap((char*)(heap), HEAP_MAX_SIZE); \ |
| } while (0) |
| |
| static int |
| internal_function |
| #if __STD_C |
| heap_trim(heap_info *heap, size_t pad) |
| #else |
| heap_trim(heap, pad) heap_info *heap; size_t pad; |
| #endif |
| { |
| mstate ar_ptr = heap->ar_ptr; |
| unsigned long pagesz = mp_.pagesize; |
| mchunkptr top_chunk = top(ar_ptr), p, bck, fwd; |
| heap_info *prev_heap; |
| long new_size, top_size, extra; |
| |
| /* Can this heap go away completely? */ |
| while(top_chunk == chunk_at_offset(heap, sizeof(*heap))) { |
| prev_heap = heap->prev; |
| p = chunk_at_offset(prev_heap, prev_heap->size - (MINSIZE-2*SIZE_SZ)); |
| assert(p->size == (0|PREV_INUSE)); /* must be fencepost */ |
| p = prev_chunk(p); |
| new_size = chunksize(p) + (MINSIZE-2*SIZE_SZ); |
| assert(new_size>0 && new_size<(long)(2*MINSIZE)); |
| if(!prev_inuse(p)) |
| new_size += p->prev_size; |
| assert(new_size>0 && new_size<HEAP_MAX_SIZE); |
| if(new_size + (HEAP_MAX_SIZE - prev_heap->size) < pad + MINSIZE + pagesz) |
| break; |
| ar_ptr->system_mem -= heap->size; |
| arena_mem -= heap->size; |
| delete_heap(heap); |
| heap = prev_heap; |
| if(!prev_inuse(p)) { /* consolidate backward */ |
| p = prev_chunk(p); |
| unlink(p, bck, fwd); |
| } |
| assert(((unsigned long)((char*)p + new_size) & (pagesz-1)) == 0); |
| assert( ((char*)p + new_size) == ((char*)heap + heap->size) ); |
| top(ar_ptr) = top_chunk = p; |
| set_head(top_chunk, new_size | PREV_INUSE); |
| /*check_chunk(ar_ptr, top_chunk);*/ |
| } |
| top_size = chunksize(top_chunk); |
| extra = (top_size - pad - MINSIZE - 1) & ~(pagesz - 1); |
| if(extra < (long)pagesz) |
| return 0; |
| /* Try to shrink. */ |
| if(shrink_heap(heap, extra) != 0) |
| return 0; |
| ar_ptr->system_mem -= extra; |
| arena_mem -= extra; |
| |
| /* Success. Adjust top accordingly. */ |
| set_head(top_chunk, (top_size - extra) | PREV_INUSE); |
| /*check_chunk(ar_ptr, top_chunk);*/ |
| return 1; |
| } |
| |
| /* Create a new arena with initial size "size". */ |
| |
| static mstate |
| _int_new_arena(size_t size) |
| { |
| mstate a; |
| heap_info *h; |
| char *ptr; |
| unsigned long misalign; |
| |
| h = new_heap(size + (sizeof(*h) + sizeof(*a) + MALLOC_ALIGNMENT), |
| mp_.top_pad); |
| if(!h) { |
| /* Maybe size is too large to fit in a single heap. So, just try |
| to create a minimally-sized arena and let _int_malloc() attempt |
| to deal with the large request via mmap_chunk(). */ |
| h = new_heap(sizeof(*h) + sizeof(*a) + MALLOC_ALIGNMENT, mp_.top_pad); |
| if(!h) |
| return 0; |
| } |
| a = h->ar_ptr = (mstate)(h+1); |
| malloc_init_state(a); |
| /*a->next = NULL;*/ |
| a->system_mem = a->max_system_mem = h->size; |
| arena_mem += h->size; |
| #ifdef NO_THREADS |
| if((unsigned long)(mp_.mmapped_mem + arena_mem + main_arena.system_mem) > |
| mp_.max_total_mem) |
| mp_.max_total_mem = mp_.mmapped_mem + arena_mem + main_arena.system_mem; |
| #endif |
| |
| /* Set up the top chunk, with proper alignment. */ |
| ptr = (char *)(a + 1); |
| misalign = (unsigned long)chunk2mem(ptr) & MALLOC_ALIGN_MASK; |
| if (misalign > 0) |
| ptr += MALLOC_ALIGNMENT - misalign; |
| top(a) = (mchunkptr)ptr; |
| set_head(top(a), (((char*)h + h->size) - ptr) | PREV_INUSE); |
| |
| tsd_setspecific(arena_key, (Void_t *)a); |
| mutex_init(&a->mutex); |
| (void)mutex_lock(&a->mutex); |
| |
| #ifdef PER_THREAD |
| (void)mutex_lock(&list_lock); |
| #endif |
| |
| /* Add the new arena to the global list. */ |
| a->next = main_arena.next; |
| atomic_write_barrier (); |
| main_arena.next = a; |
| |
| #ifdef PER_THREAD |
| ++narenas; |
| |
| (void)mutex_unlock(&list_lock); |
| #endif |
| |
| THREAD_STAT(++(a->stat_lock_loop)); |
| |
| return a; |
| } |
| |
| |
| #ifdef PER_THREAD |
| static mstate |
| get_free_list (void) |
| { |
| mstate result = free_list; |
| if (result != NULL) |
| { |
| (void)mutex_lock(&list_lock); |
| result = free_list; |
| if (result != NULL) |
| free_list = result->next_free; |
| (void)mutex_unlock(&list_lock); |
| |
| if (result != NULL) |
| { |
| (void)mutex_lock(&result->mutex); |
| tsd_setspecific(arena_key, (Void_t *)result); |
| THREAD_STAT(++(result->stat_lock_loop)); |
| } |
| } |
| |
| return result; |
| } |
| |
| |
| static mstate |
| reused_arena (void) |
| { |
| if (narenas <= mp_.arena_test) |
| return NULL; |
| |
| static int narenas_limit; |
| if (narenas_limit == 0) |
| { |
| if (mp_.arena_max != 0) |
| narenas_limit = mp_.arena_max; |
| else |
| { |
| int n = __get_nprocs (); |
| |
| if (n >= 1) |
| narenas_limit = NARENAS_FROM_NCORES (n); |
| else |
| /* We have no information about the system. Assume two |
| cores. */ |
| narenas_limit = NARENAS_FROM_NCORES (2); |
| } |
| } |
| |
| if (narenas < narenas_limit) |
| return NULL; |
| |
| mstate result; |
| static mstate next_to_use; |
| if (next_to_use == NULL) |
| next_to_use = &main_arena; |
| |
| result = next_to_use; |
| do |
| { |
| if (!mutex_trylock(&result->mutex)) |
| goto out; |
| |
| result = result->next; |
| } |
| while (result != next_to_use); |
| |
| /* No arena available. Wait for the next in line. */ |
| (void)mutex_lock(&result->mutex); |
| |
| out: |
| tsd_setspecific(arena_key, (Void_t *)result); |
| THREAD_STAT(++(result->stat_lock_loop)); |
| next_to_use = result->next; |
| |
| return result; |
| } |
| #endif |
| |
| static mstate |
| internal_function |
| #if __STD_C |
| arena_get2(mstate a_tsd, size_t size) |
| #else |
| arena_get2(a_tsd, size) mstate a_tsd; size_t size; |
| #endif |
| { |
| mstate a; |
| |
| #ifdef PER_THREAD |
| if ((a = get_free_list ()) == NULL |
| && (a = reused_arena ()) == NULL) |
| /* Nothing immediately available, so generate a new arena. */ |
| a = _int_new_arena(size); |
| #else |
| if(!a_tsd) |
| a = a_tsd = &main_arena; |
| else { |
| a = a_tsd->next; |
| if(!a) { |
| /* This can only happen while initializing the new arena. */ |
| (void)mutex_lock(&main_arena.mutex); |
| THREAD_STAT(++(main_arena.stat_lock_wait)); |
| return &main_arena; |
| } |
| } |
| |
| /* Check the global, circularly linked list for available arenas. */ |
| bool retried = false; |
| repeat: |
| do { |
| if(!mutex_trylock(&a->mutex)) { |
| if (retried) |
| (void)mutex_unlock(&list_lock); |
| THREAD_STAT(++(a->stat_lock_loop)); |
| tsd_setspecific(arena_key, (Void_t *)a); |
| return a; |
| } |
| a = a->next; |
| } while(a != a_tsd); |
| |
| /* If not even the list_lock can be obtained, try again. This can |
| happen during `atfork', or for example on systems where thread |
| creation makes it temporarily impossible to obtain _any_ |
| locks. */ |
| if(!retried && mutex_trylock(&list_lock)) { |
| /* We will block to not run in a busy loop. */ |
| (void)mutex_lock(&list_lock); |
| |
| /* Since we blocked there might be an arena available now. */ |
| retried = true; |
| a = a_tsd; |
| goto repeat; |
| } |
| |
| /* Nothing immediately available, so generate a new arena. */ |
| a = _int_new_arena(size); |
| (void)mutex_unlock(&list_lock); |
| #endif |
| |
| return a; |
| } |
| |
| #ifdef PER_THREAD |
| static void __attribute__ ((section ("__libc_thread_freeres_fn"))) |
| arena_thread_freeres (void) |
| { |
| Void_t *vptr = NULL; |
| mstate a = tsd_getspecific(arena_key, vptr); |
| tsd_setspecific(arena_key, NULL); |
| |
| if (a != NULL) |
| { |
| (void)mutex_lock(&list_lock); |
| a->next_free = free_list; |
| free_list = a; |
| (void)mutex_unlock(&list_lock); |
| } |
| } |
| text_set_element (__libc_thread_subfreeres, arena_thread_freeres); |
| #endif |
| |
| #endif /* USE_ARENAS */ |
| |
| /* |
| * Local variables: |
| * c-basic-offset: 2 |
| * End: |
| */ |