919 lines
25 KiB
C
919 lines
25 KiB
C
/* Malloc implementation for multiple threads without lock contention.
|
||
Copyright (C) 2001,2002,2003,2004,2005,2006 Free Software Foundation, Inc.
|
||
This file is part of the GNU C Library.
|
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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. */
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||
|
||
#include <stdbool.h>
|
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|
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/* Compile-time constants. */
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#define HEAP_MIN_SIZE (32*1024)
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#ifndef HEAP_MAX_SIZE
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# ifdef DEFAULT_MMAP_THRESHOLD_MAX
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# define HEAP_MAX_SIZE (2 * DEFAULT_MMAP_THRESHOLD_MAX)
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# else
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# define HEAP_MAX_SIZE (1024*1024) /* must be a power of two */
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# endif
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#endif
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/* HEAP_MIN_SIZE and HEAP_MAX_SIZE limit the size of mmap()ed heaps
|
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that are dynamically created for multi-threaded programs. The
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maximum size must be a power of two, for fast determination of
|
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which heap belongs to a chunk. It should be much larger than the
|
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mmap threshold, so that requests with a size just below that
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threshold can be fulfilled without creating too many heaps. */
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#ifndef THREAD_STATS
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#define THREAD_STATS 0
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#endif
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/* If THREAD_STATS is non-zero, some statistics on mutex locking are
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computed. */
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/***************************************************************************/
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#define top(ar_ptr) ((ar_ptr)->top)
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/* A heap is a single contiguous memory region holding (coalesceable)
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malloc_chunks. It is allocated with mmap() and always starts at an
|
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address aligned to HEAP_MAX_SIZE. Not used unless compiling with
|
||
USE_ARENAS. */
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typedef struct _heap_info {
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mstate ar_ptr; /* Arena for this heap. */
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struct _heap_info *prev; /* Previous heap. */
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||
size_t size; /* Current size in bytes. */
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/* Make sure the following data is properly aligned, particularly
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that sizeof (heap_info) + 2 * SIZE_SZ is a multiple of
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MALLOG_ALIGNMENT. */
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char pad[-5 * SIZE_SZ & MALLOC_ALIGN_MASK];
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} heap_info;
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||
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/* Get a compile-time error if the heap_info padding is not correct
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to make alignment work as expected in sYSMALLOc. */
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extern int sanity_check_heap_info_alignment[(sizeof (heap_info)
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+ 2 * SIZE_SZ) % MALLOC_ALIGNMENT
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? -1 : 1];
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/* Thread specific data */
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static tsd_key_t arena_key;
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static mutex_t list_lock;
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#if THREAD_STATS
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static int stat_n_heaps;
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#define THREAD_STAT(x) x
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#else
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#define THREAD_STAT(x) do ; while(0)
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#endif
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/* Mapped memory in non-main arenas (reliable only for NO_THREADS). */
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static unsigned long arena_mem;
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/* Already initialized? */
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int __malloc_initialized = -1;
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/**************************************************************************/
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#if USE_ARENAS
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/* arena_get() acquires an arena and locks the corresponding mutex.
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First, try the one last locked successfully by this thread. (This
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is the common case and handled with a macro for speed.) Then, loop
|
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once over the circularly linked list of arenas. If no arena is
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readily available, create a new one. In this latter case, `size'
|
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is just a hint as to how much memory will be required immediately
|
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in the new arena. */
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#define arena_get(ptr, size) do { \
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Void_t *vptr = NULL; \
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ptr = (mstate)tsd_getspecific(arena_key, vptr); \
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if(ptr && !mutex_trylock(&ptr->mutex)) { \
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THREAD_STAT(++(ptr->stat_lock_direct)); \
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} else \
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ptr = arena_get2(ptr, (size)); \
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||
} while(0)
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/* find the heap and corresponding arena for a given ptr */
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#define heap_for_ptr(ptr) \
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((heap_info *)((unsigned long)(ptr) & ~(HEAP_MAX_SIZE-1)))
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#define arena_for_chunk(ptr) \
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(chunk_non_main_arena(ptr) ? heap_for_ptr(ptr)->ar_ptr : &main_arena)
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#else /* !USE_ARENAS */
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/* There is only one arena, main_arena. */
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#if THREAD_STATS
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#define arena_get(ar_ptr, sz) do { \
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ar_ptr = &main_arena; \
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if(!mutex_trylock(&ar_ptr->mutex)) \
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||
++(ar_ptr->stat_lock_direct); \
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||
else { \
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(void)mutex_lock(&ar_ptr->mutex); \
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++(ar_ptr->stat_lock_wait); \
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||
} \
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||
} while(0)
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#else
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#define arena_get(ar_ptr, sz) do { \
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||
ar_ptr = &main_arena; \
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(void)mutex_lock(&ar_ptr->mutex); \
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} while(0)
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#endif
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||
#define arena_for_chunk(ptr) (&main_arena)
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||
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#endif /* USE_ARENAS */
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||
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/**************************************************************************/
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#ifndef NO_THREADS
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/* atfork support. */
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static __malloc_ptr_t (*save_malloc_hook) (size_t __size,
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__const __malloc_ptr_t);
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# if !defined _LIBC || (defined SHARED && !USE___THREAD)
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static __malloc_ptr_t (*save_memalign_hook) (size_t __align, size_t __size,
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__const __malloc_ptr_t);
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||
# endif
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static void (*save_free_hook) (__malloc_ptr_t __ptr,
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__const __malloc_ptr_t);
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static Void_t* save_arena;
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/* Magic value for the thread-specific arena pointer when
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malloc_atfork() is in use. */
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#define ATFORK_ARENA_PTR ((Void_t*)-1)
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/* The following hooks are used while the `atfork' handling mechanism
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||
is active. */
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||
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||
static Void_t*
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||
malloc_atfork(size_t sz, const Void_t *caller)
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{
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Void_t *vptr = NULL;
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Void_t *victim;
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||
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tsd_getspecific(arena_key, vptr);
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||
if(vptr == ATFORK_ARENA_PTR) {
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/* We are the only thread that may allocate at all. */
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||
if(save_malloc_hook != malloc_check) {
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return _int_malloc(&main_arena, sz);
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||
} else {
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||
if(top_check()<0)
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return 0;
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||
victim = _int_malloc(&main_arena, sz+1);
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return mem2mem_check(victim, sz);
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}
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} else {
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/* Suspend the thread until the `atfork' handlers have completed.
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By that time, the hooks will have been reset as well, so that
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mALLOc() can be used again. */
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(void)mutex_lock(&list_lock);
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(void)mutex_unlock(&list_lock);
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return public_mALLOc(sz);
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}
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}
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static void
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free_atfork(Void_t* mem, const Void_t *caller)
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||
{
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||
Void_t *vptr = NULL;
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||
mstate ar_ptr;
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||
mchunkptr p; /* chunk corresponding to mem */
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||
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if (mem == 0) /* free(0) has no effect */
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return;
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p = mem2chunk(mem); /* do not bother to replicate free_check here */
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#if HAVE_MMAP
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if (chunk_is_mmapped(p)) /* release mmapped memory. */
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{
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munmap_chunk(p);
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return;
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}
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#endif
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||
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ar_ptr = arena_for_chunk(p);
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||
tsd_getspecific(arena_key, vptr);
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if(vptr != ATFORK_ARENA_PTR)
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(void)mutex_lock(&ar_ptr->mutex);
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_int_free(ar_ptr, mem);
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if(vptr != ATFORK_ARENA_PTR)
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||
(void)mutex_unlock(&ar_ptr->mutex);
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||
}
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||
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||
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/* Counter for number of times the list is locked by the same thread. */
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static unsigned int atfork_recursive_cntr;
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/* The following two functions are registered via thread_atfork() to
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make sure that the mutexes remain in a consistent state in the
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fork()ed version of a thread. Also adapt the malloc and free hooks
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temporarily, because the `atfork' handler mechanism may use
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malloc/free internally (e.g. in LinuxThreads). */
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static void
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||
ptmalloc_lock_all (void)
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||
{
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||
mstate ar_ptr;
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||
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||
if(__malloc_initialized < 1)
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return;
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||
if (mutex_trylock(&list_lock))
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||
{
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Void_t *my_arena;
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tsd_getspecific(arena_key, my_arena);
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if (my_arena == ATFORK_ARENA_PTR)
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/* This is the same thread which already locks the global list.
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Just bump the counter. */
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goto out;
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||
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/* This thread has to wait its turn. */
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||
(void)mutex_lock(&list_lock);
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}
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for(ar_ptr = &main_arena;;) {
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(void)mutex_lock(&ar_ptr->mutex);
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ar_ptr = ar_ptr->next;
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if(ar_ptr == &main_arena) break;
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}
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save_malloc_hook = __malloc_hook;
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save_free_hook = __free_hook;
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__malloc_hook = malloc_atfork;
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__free_hook = free_atfork;
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/* Only the current thread may perform malloc/free calls now. */
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tsd_getspecific(arena_key, save_arena);
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tsd_setspecific(arena_key, ATFORK_ARENA_PTR);
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out:
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++atfork_recursive_cntr;
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}
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||
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||
static void
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ptmalloc_unlock_all (void)
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{
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||
mstate ar_ptr;
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||
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if(__malloc_initialized < 1)
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return;
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if (--atfork_recursive_cntr != 0)
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return;
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tsd_setspecific(arena_key, save_arena);
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__malloc_hook = save_malloc_hook;
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__free_hook = save_free_hook;
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for(ar_ptr = &main_arena;;) {
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(void)mutex_unlock(&ar_ptr->mutex);
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ar_ptr = ar_ptr->next;
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if(ar_ptr == &main_arena) break;
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}
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(void)mutex_unlock(&list_lock);
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||
}
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||
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||
#ifdef __linux__
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||
|
||
/* In NPTL, unlocking a mutex in the child process after a
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fork() is currently unsafe, whereas re-initializing it is safe and
|
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does not leak resources. Therefore, a special atfork handler is
|
||
installed for the child. */
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||
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||
static void
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ptmalloc_unlock_all2 (void)
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{
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||
mstate ar_ptr;
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||
|
||
if(__malloc_initialized < 1)
|
||
return;
|
||
#if defined _LIBC || defined MALLOC_HOOKS
|
||
tsd_setspecific(arena_key, save_arena);
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||
__malloc_hook = save_malloc_hook;
|
||
__free_hook = save_free_hook;
|
||
#endif
|
||
for(ar_ptr = &main_arena;;) {
|
||
mutex_init(&ar_ptr->mutex);
|
||
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 _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 && memcmp (envline, "MMAP_MAX_", 9) == 0)
|
||
mALLOPt(M_MMAP_MAX, atoi(&envline[10]));
|
||
break;
|
||
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();
|
||
}
|
||
if(__malloc_initialize_hook != NULL)
|
||
(*__malloc_initialize_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;
|
||
THREAD_STAT(stat_n_heaps++);
|
||
return h;
|
||
}
|
||
|
||
/* Grow or shrink a heap. size is automatically rounded up to a
|
||
multiple of the page size if it is positive. */
|
||
|
||
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;
|
||
|
||
if(diff >= 0) {
|
||
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(mprotect((char *)h + h->size, diff, PROT_READ|PROT_WRITE) != 0)
|
||
return -2;
|
||
} 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;
|
||
/*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 + (pagesz-1))/pagesz - 1) * pagesz;
|
||
if(extra < (long)pagesz)
|
||
return 0;
|
||
/* Try to shrink. */
|
||
if(grow_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);
|
||
|
||
return a;
|
||
}
|
||
|
||
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;
|
||
|
||
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);
|
||
if(a)
|
||
{
|
||
tsd_setspecific(arena_key, (Void_t *)a);
|
||
mutex_init(&a->mutex);
|
||
mutex_lock(&a->mutex); /* remember result */
|
||
|
||
/* Add the new arena to the global list. */
|
||
a->next = main_arena.next;
|
||
atomic_write_barrier ();
|
||
main_arena.next = a;
|
||
|
||
THREAD_STAT(++(a->stat_lock_loop));
|
||
}
|
||
(void)mutex_unlock(&list_lock);
|
||
|
||
return a;
|
||
}
|
||
|
||
#endif /* USE_ARENAS */
|
||
|
||
/*
|
||
* Local variables:
|
||
* c-basic-offset: 2
|
||
* End:
|
||
*/
|