diff options
Diffstat (limited to 'malloc/arena.c')
| -rw-r--r-- | malloc/arena.c | 179 |
1 files changed, 119 insertions, 60 deletions
diff --git a/malloc/arena.c b/malloc/arena.c index 026f2c7..0dcb7cb 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -1,5 +1,6 @@ /* Malloc implementation for multiple threads without lock contention. - Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc. + Copyright (C) 2001,2002,2003,2004,2005,2006,2007 + Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Wolfram Gloger <wg@malloc.de>, 2001. @@ -18,13 +19,17 @@ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ -/* $Id$ */ +#include <stdbool.h> /* Compile-time constants. */ #define HEAP_MIN_SIZE (32*1024) #ifndef HEAP_MAX_SIZE -#define HEAP_MAX_SIZE (1024*1024) /* must be a power of two */ +# 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 @@ -55,9 +60,20 @@ 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 pad; /* Make sure the following data is properly aligned. */ + 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; @@ -208,6 +224,10 @@ free_atfork(Void_t* mem, const Void_t *caller) (void)mutex_unlock(&ar_ptr->mutex); } + +/* 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 @@ -221,7 +241,18 @@ ptmalloc_lock_all (void) if(__malloc_initialized < 1) return; - (void)mutex_lock(&list_lock); + 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; @@ -234,6 +265,8 @@ ptmalloc_lock_all (void) /* 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 @@ -243,6 +276,8 @@ ptmalloc_unlock_all (void) 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; @@ -256,7 +291,7 @@ ptmalloc_unlock_all (void) #ifdef __linux__ -/* In LinuxThreads, unlocking a mutex in the child process after a +/* 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. */ @@ -279,6 +314,7 @@ ptmalloc_unlock_all2 (void) if(ar_ptr == &main_arena) break; } mutex_init(&list_lock); + atfork_recursive_cntr = 0; } #else @@ -353,8 +389,6 @@ libc_hidden_proto (_dl_open_hook); # endif # if defined SHARED && defined USE_TLS && !USE___THREAD -# include <stdbool.h> - /* 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, @@ -482,8 +516,13 @@ ptmalloc_init (void) s = &envline[7]; break; case 8: - if (! secure && memcmp (envline, "TOP_PAD_", 8) == 0) - mALLOPt(M_TOP_PAD, atoi(&envline[9])); + 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 && memcmp (envline, "MMAP_MAX_", 9) == 0) @@ -510,6 +549,8 @@ ptmalloc_init (void) 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_"))) @@ -517,8 +558,8 @@ ptmalloc_init (void) } s = getenv("MALLOC_CHECK_"); #endif - if(s) { - if(s[0]) mALLOPt(M_CHECK_ACTION, (int)(s[0] - '0')); + if(s && s[0]) { + mALLOPt(M_CHECK_ACTION, (int)(s[0] - '0')); if (check_action != 0) __malloc_check_init(); } @@ -654,6 +695,7 @@ new_heap(size, top_pad) size_t size, top_pad; } h = (heap_info *)p2; h->size = size; + h->mprotect_size = size; THREAD_STAT(stat_n_heaps++); return h; } @@ -674,19 +716,36 @@ grow_heap(h, diff) heap_info *h; long diff; if(diff >= 0) { diff = (diff + page_mask) & ~page_mask; new_size = (long)h->size + diff; - if(new_size > HEAP_MAX_SIZE) + if((unsigned long) new_size > (unsigned long) HEAP_MAX_SIZE) return -1; - if(mprotect((char *)h + h->size, diff, PROT_READ|PROT_WRITE) != 0) - return -2; + 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; + } } else { 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. */ - if((char *)MMAP((char *)h + new_size, -diff, PROT_NONE, - MAP_PRIVATE|MAP_FIXED) == (char *) MAP_FAILED) - return -2; +#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; @@ -759,6 +818,48 @@ heap_trim(heap, pad) heap_info *heap; size_t pad; 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); + + return a; +} + static mstate internal_function #if __STD_C @@ -829,48 +930,6 @@ arena_get2(a_tsd, size) mstate a_tsd; size_t size; return a; } -/* Create a new arena with initial size "size". */ - -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); - - return a; -} - #endif /* USE_ARENAS */ /* |