mirror of
git://sourceware.org/git/glibc.git
synced 2024-11-21 01:12:26 +08:00
927 lines
26 KiB
C
927 lines
26 KiB
C
/* Malloc implementation for multiple threads without lock contention.
|
|
Copyright (C) 2001-2014 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, see <http://www.gnu.org/licenses/>. */
|
|
|
|
#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. */
|
|
|
|
/***************************************************************************/
|
|
|
|
#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. */
|
|
|
|
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 = MUTEX_INITIALIZER;
|
|
static size_t narenas = 1;
|
|
static mstate free_list;
|
|
|
|
/* Mapped memory in non-main arenas (reliable only for NO_THREADS). */
|
|
static unsigned long arena_mem;
|
|
|
|
/* Already initialized? */
|
|
int __malloc_initialized = -1;
|
|
|
|
/**************************************************************************/
|
|
|
|
|
|
/* 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 *vptr = NULL; \
|
|
ptr = (mstate) tsd_getspecific (arena_key, vptr); \
|
|
} while (0)
|
|
|
|
#define arena_lock(ptr, size) do { \
|
|
if (ptr) \
|
|
(void) mutex_lock (&ptr->mutex); \
|
|
else \
|
|
ptr = arena_get2 (ptr, (size), NULL); \
|
|
} while (0)
|
|
|
|
/* 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)
|
|
|
|
|
|
/**************************************************************************/
|
|
|
|
#ifndef NO_THREADS
|
|
|
|
/* atfork support. */
|
|
|
|
static void *(*save_malloc_hook)(size_t __size, const void *);
|
|
static void (*save_free_hook) (void *__ptr, const void *);
|
|
static void *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 *) -1)
|
|
|
|
/* The following hooks are used while the `atfork' handling mechanism
|
|
is active. */
|
|
|
|
static void *
|
|
malloc_atfork (size_t sz, const void *caller)
|
|
{
|
|
void *vptr = NULL;
|
|
void *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 __libc_malloc (sz);
|
|
}
|
|
}
|
|
|
|
static void
|
|
free_atfork (void *mem, const void *caller)
|
|
{
|
|
void *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 (chunk_is_mmapped (p)) /* release mmapped memory. */
|
|
{
|
|
munmap_chunk (p);
|
|
return;
|
|
}
|
|
|
|
ar_ptr = arena_for_chunk (p);
|
|
tsd_getspecific (arena_key, vptr);
|
|
_int_free (ar_ptr, p, vptr == ATFORK_ARENA_PTR);
|
|
}
|
|
|
|
|
|
/* 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 *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;
|
|
|
|
tsd_setspecific (arena_key, save_arena);
|
|
__malloc_hook = save_malloc_hook;
|
|
__free_hook = save_free_hook;
|
|
free_list = NULL;
|
|
for (ar_ptr = &main_arena;; )
|
|
{
|
|
mutex_init (&ar_ptr->mutex);
|
|
if (ar_ptr != save_arena)
|
|
{
|
|
ar_ptr->next_free = free_list;
|
|
free_list = ar_ptr;
|
|
}
|
|
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 /* !NO_THREADS */
|
|
|
|
/* Initialization routine. */
|
|
#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;
|
|
}
|
|
|
|
|
|
#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
|
|
|
|
static void
|
|
ptmalloc_init (void)
|
|
{
|
|
if (__malloc_initialized >= 0)
|
|
return;
|
|
|
|
__malloc_initialized = 0;
|
|
|
|
#ifdef 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
|
|
|
|
tsd_key_create (&arena_key, NULL);
|
|
tsd_setspecific (arena_key, (void *) &main_arena);
|
|
thread_atfork (ptmalloc_lock_all, ptmalloc_unlock_all, ptmalloc_unlock_all2);
|
|
const char *s = NULL;
|
|
if (__glibc_likely (_environ != NULL))
|
|
{
|
|
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 (!__builtin_expect (__libc_enable_secure, 0))
|
|
{
|
|
if (memcmp (envline, "TOP_PAD_", 8) == 0)
|
|
__libc_mallopt (M_TOP_PAD, atoi (&envline[9]));
|
|
else if (memcmp (envline, "PERTURB_", 8) == 0)
|
|
__libc_mallopt (M_PERTURB, atoi (&envline[9]));
|
|
}
|
|
break;
|
|
case 9:
|
|
if (!__builtin_expect (__libc_enable_secure, 0))
|
|
{
|
|
if (memcmp (envline, "MMAP_MAX_", 9) == 0)
|
|
__libc_mallopt (M_MMAP_MAX, atoi (&envline[10]));
|
|
else if (memcmp (envline, "ARENA_MAX", 9) == 0)
|
|
__libc_mallopt (M_ARENA_MAX, atoi (&envline[10]));
|
|
}
|
|
break;
|
|
case 10:
|
|
if (!__builtin_expect (__libc_enable_secure, 0))
|
|
{
|
|
if (memcmp (envline, "ARENA_TEST", 10) == 0)
|
|
__libc_mallopt (M_ARENA_TEST, atoi (&envline[11]));
|
|
}
|
|
break;
|
|
case 15:
|
|
if (!__builtin_expect (__libc_enable_secure, 0))
|
|
{
|
|
if (memcmp (envline, "TRIM_THRESHOLD_", 15) == 0)
|
|
__libc_mallopt (M_TRIM_THRESHOLD, atoi (&envline[16]));
|
|
else if (memcmp (envline, "MMAP_THRESHOLD_", 15) == 0)
|
|
__libc_mallopt (M_MMAP_THRESHOLD, atoi (&envline[16]));
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (s && s[0])
|
|
{
|
|
__libc_mallopt (M_CHECK_ACTION, (int) (s[0] - '0'));
|
|
if (check_action != 0)
|
|
__malloc_check_init ();
|
|
}
|
|
void (*hook) (void) = atomic_forced_read (__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 MALLOC_DEBUG > 1
|
|
|
|
/* Print the complete contents of a single heap to stderr. */
|
|
|
|
static void
|
|
dump_heap (heap_info *heap)
|
|
{
|
|
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
|
|
new_heap (size_t size, size_t top_pad)
|
|
{
|
|
size_t page_mask = GLRO (dl_pagesize) - 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_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_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_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;
|
|
LIBC_PROBE (memory_heap_new, 2, h, h->size);
|
|
return h;
|
|
}
|
|
|
|
/* Grow a heap. size is automatically rounded up to a
|
|
multiple of the page size. */
|
|
|
|
static int
|
|
grow_heap (heap_info *h, long diff)
|
|
{
|
|
size_t page_mask = GLRO (dl_pagesize) - 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;
|
|
LIBC_PROBE (memory_heap_more, 2, h, h->size);
|
|
return 0;
|
|
}
|
|
|
|
/* Shrink a heap. */
|
|
|
|
static int
|
|
shrink_heap (heap_info *h, long diff)
|
|
{
|
|
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. See malloc-sysdep.h to know when this is true. */
|
|
if (__glibc_unlikely (check_may_shrink_heap ()))
|
|
{
|
|
if ((char *) MMAP ((char *) h + new_size, diff, PROT_NONE,
|
|
MAP_FIXED) == (char *) MAP_FAILED)
|
|
return -2;
|
|
|
|
h->mprotect_size = new_size;
|
|
}
|
|
else
|
|
__madvise ((char *) h + new_size, diff, MADV_DONTNEED);
|
|
/*fprintf(stderr, "shrink %p %08lx\n", h, new_size);*/
|
|
|
|
h->size = new_size;
|
|
LIBC_PROBE (memory_heap_less, 2, h, h->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
|
|
heap_trim (heap_info *heap, size_t pad)
|
|
{
|
|
mstate ar_ptr = heap->ar_ptr;
|
|
unsigned long pagesz = GLRO (dl_pagesize);
|
|
mchunkptr top_chunk = top (ar_ptr), p, bck, fwd;
|
|
heap_info *prev_heap;
|
|
long new_size, top_size, extra, prev_size, misalign;
|
|
|
|
/* Can this heap go away completely? */
|
|
while (top_chunk == chunk_at_offset (heap, sizeof (*heap)))
|
|
{
|
|
prev_heap = heap->prev;
|
|
prev_size = prev_heap->size - (MINSIZE - 2 * SIZE_SZ);
|
|
p = chunk_at_offset (prev_heap, prev_size);
|
|
/* fencepost must be properly aligned. */
|
|
misalign = ((long) p) & MALLOC_ALIGN_MASK;
|
|
p = chunk_at_offset (prev_heap, prev_size - misalign);
|
|
assert (p->size == (0 | PREV_INUSE)); /* must be fencepost */
|
|
p = prev_chunk (p);
|
|
new_size = chunksize (p) + (MINSIZE - 2 * SIZE_SZ) + misalign;
|
|
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;
|
|
LIBC_PROBE (memory_heap_free, 2, heap, 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;
|
|
|
|
/* 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);
|
|
|
|
LIBC_PROBE (memory_arena_new, 2, a, size);
|
|
tsd_setspecific (arena_key, (void *) a);
|
|
mutex_init (&a->mutex);
|
|
(void) mutex_lock (&a->mutex);
|
|
|
|
(void) mutex_lock (&list_lock);
|
|
|
|
/* Add the new arena to the global list. */
|
|
a->next = main_arena.next;
|
|
atomic_write_barrier ();
|
|
main_arena.next = a;
|
|
|
|
(void) mutex_unlock (&list_lock);
|
|
|
|
return a;
|
|
}
|
|
|
|
|
|
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)
|
|
{
|
|
LIBC_PROBE (memory_arena_reuse_free_list, 1, result);
|
|
(void) mutex_lock (&result->mutex);
|
|
tsd_setspecific (arena_key, (void *) result);
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/* Lock and return an arena that can be reused for memory allocation.
|
|
Avoid AVOID_ARENA as we have already failed to allocate memory in
|
|
it and it is currently locked. */
|
|
static mstate
|
|
reused_arena (mstate avoid_arena)
|
|
{
|
|
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);
|
|
|
|
/* Avoid AVOID_ARENA as we have already failed to allocate memory
|
|
in that arena and it is currently locked. */
|
|
if (result == avoid_arena)
|
|
result = result->next;
|
|
|
|
/* No arena available. Wait for the next in line. */
|
|
LIBC_PROBE (memory_arena_reuse_wait, 3, &result->mutex, result, avoid_arena);
|
|
(void) mutex_lock (&result->mutex);
|
|
|
|
out:
|
|
LIBC_PROBE (memory_arena_reuse, 2, result, avoid_arena);
|
|
tsd_setspecific (arena_key, (void *) result);
|
|
next_to_use = result->next;
|
|
|
|
return result;
|
|
}
|
|
|
|
static mstate
|
|
internal_function
|
|
arena_get2 (mstate a_tsd, size_t size, mstate avoid_arena)
|
|
{
|
|
mstate a;
|
|
|
|
static size_t narenas_limit;
|
|
|
|
a = get_free_list ();
|
|
if (a == NULL)
|
|
{
|
|
/* Nothing immediately available, so generate a new arena. */
|
|
if (narenas_limit == 0)
|
|
{
|
|
if (mp_.arena_max != 0)
|
|
narenas_limit = mp_.arena_max;
|
|
else if (narenas > mp_.arena_test)
|
|
{
|
|
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);
|
|
}
|
|
}
|
|
repeat:;
|
|
size_t n = narenas;
|
|
/* NB: the following depends on the fact that (size_t)0 - 1 is a
|
|
very large number and that the underflow is OK. If arena_max
|
|
is set the value of arena_test is irrelevant. If arena_test
|
|
is set but narenas is not yet larger or equal to arena_test
|
|
narenas_limit is 0. There is no possibility for narenas to
|
|
be too big for the test to always fail since there is not
|
|
enough address space to create that many arenas. */
|
|
if (__glibc_unlikely (n <= narenas_limit - 1))
|
|
{
|
|
if (catomic_compare_and_exchange_bool_acq (&narenas, n + 1, n))
|
|
goto repeat;
|
|
a = _int_new_arena (size);
|
|
if (__glibc_unlikely (a == NULL))
|
|
catomic_decrement (&narenas);
|
|
}
|
|
else
|
|
a = reused_arena (avoid_arena);
|
|
}
|
|
return a;
|
|
}
|
|
|
|
/* If we don't have the main arena, then maybe the failure is due to running
|
|
out of mmapped areas, so we can try allocating on the main arena.
|
|
Otherwise, it is likely that sbrk() has failed and there is still a chance
|
|
to mmap(), so try one of the other arenas. */
|
|
static mstate
|
|
arena_get_retry (mstate ar_ptr, size_t bytes)
|
|
{
|
|
LIBC_PROBE (memory_arena_retry, 2, bytes, ar_ptr);
|
|
if (ar_ptr != &main_arena)
|
|
{
|
|
(void) mutex_unlock (&ar_ptr->mutex);
|
|
ar_ptr = &main_arena;
|
|
(void) mutex_lock (&ar_ptr->mutex);
|
|
}
|
|
else
|
|
{
|
|
/* Grab ar_ptr->next prior to releasing its lock. */
|
|
mstate prev = ar_ptr->next ? ar_ptr : 0;
|
|
(void) mutex_unlock (&ar_ptr->mutex);
|
|
ar_ptr = arena_get2 (prev, bytes, ar_ptr);
|
|
}
|
|
|
|
return ar_ptr;
|
|
}
|
|
|
|
static void __attribute__ ((section ("__libc_thread_freeres_fn")))
|
|
arena_thread_freeres (void)
|
|
{
|
|
void *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);
|
|
|
|
/*
|
|
* Local variables:
|
|
* c-basic-offset: 2
|
|
* End:
|
|
*/
|