/* Malloc implementation for multiple threads without lock contention.
- Copyright (C) 2001-2015 Free Software Foundation, Inc.
+ Copyright (C) 2001-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Wolfram Gloger <wg@malloc.de>, 2001.
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/>. */
+ not, see <https://www.gnu.org/licenses/>. */
#include <stdbool.h>
+#if HAVE_TUNABLES
+# define TUNABLE_NAMESPACE malloc
+#endif
+#include <elf/dl-tunables.h>
+
/* Compile-time constants. */
#define HEAP_MIN_SIZE (32 * 1024)
+ 2 * SIZE_SZ) % MALLOC_ALIGNMENT
? -1 : 1];
-/* Thread specific data */
+/* Thread specific data. */
+
+static __thread mstate thread_arena attribute_tls_model_ie;
+
+/* Arena free list. free_list_lock synchronizes access to the
+ free_list variable below, and the next_free and attached_threads
+ members of struct malloc_state objects. No other locks must be
+ acquired after free_list_lock has been acquired. */
-static tsd_key_t arena_key;
-static mutex_t list_lock = MUTEX_INITIALIZER;
+__libc_lock_define_initialized (static, free_list_lock);
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;
+/* list_lock prevents concurrent writes to the next member of struct
+ malloc_state objects.
+
+ Read access to the next member is supposed to synchronize with the
+ atomic_write_barrier and the write to the next member in
+ _int_new_arena. This suffers from data races; see the FIXME
+ comments in _int_new_arena and reused_arena.
+
+ list_lock also prevents concurrent forks. At the time list_lock is
+ acquired, no arena lock must have been acquired, but it is
+ permitted to acquire arena locks subsequently, while list_lock is
+ acquired. */
+__libc_lock_define_initialized (static, list_lock);
/* Already initialized? */
int __malloc_initialized = -1;
in the new arena. */
#define arena_get(ptr, size) do { \
- arena_lookup (ptr); \
+ ptr = thread_arena; \
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); \
+ __libc_lock_lock (ptr->mutex); \
else \
- ptr = arena_get2 (ptr, (size), NULL); \
+ ptr = arena_get2 ((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)
+ (chunk_main_arena (ptr) ? &main_arena : heap_for_ptr (ptr)->ar_ptr)
/**************************************************************************/
-#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);
-}
-
+/* The following three functions are called around fork from a
+ multi-threaded process. We do not use the general fork handler
+ mechanism to make sure that our handlers are the last ones being
+ called, so that other fork handlers can use the malloc
+ subsystem. */
-/* 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)
+void
+__malloc_fork_lock_parent (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;
+ /* We do not acquire free_list_lock here because we completely
+ reconstruct free_list in __malloc_fork_unlock_child. */
- /* This thread has to wait its turn. */
- (void) mutex_lock (&list_lock);
- }
- for (ar_ptr = &main_arena;; )
+ __libc_lock_lock (list_lock);
+
+ for (mstate ar_ptr = &main_arena;; )
{
- (void) mutex_lock (&ar_ptr->mutex);
+ __libc_lock_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)
+void
+__malloc_fork_unlock_parent (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;; )
+ for (mstate ar_ptr = &main_arena;; )
{
- (void) mutex_unlock (&ar_ptr->mutex);
+ __libc_lock_unlock (ar_ptr->mutex);
ar_ptr = ar_ptr->next;
if (ar_ptr == &main_arena)
break;
}
- (void) mutex_unlock (&list_lock);
+ __libc_lock_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)
+void
+__malloc_fork_unlock_child (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;
+ /* Push all arenas to the free list, except thread_arena, which is
+ attached to the current thread. */
+ __libc_lock_init (free_list_lock);
+ if (thread_arena != NULL)
+ thread_arena->attached_threads = 1;
free_list = NULL;
- for (ar_ptr = &main_arena;; )
+ for (mstate ar_ptr = &main_arena;; )
{
- mutex_init (&ar_ptr->mutex);
- if (ar_ptr != save_arena)
+ __libc_lock_init (ar_ptr->mutex);
+ if (ar_ptr != thread_arena)
{
+ /* This arena is no longer attached to any thread. */
+ ar_ptr->attached_threads = 0;
ar_ptr->next_free = free_list;
free_list = ar_ptr;
}
if (ar_ptr == &main_arena)
break;
}
- mutex_init (&list_lock);
- atfork_recursive_cntr = 0;
+
+ __libc_lock_init (list_lock);
}
-# else
+#if HAVE_TUNABLES
+void
+TUNABLE_CALLBACK (set_mallopt_check) (tunable_val_t *valp)
+{
+ int32_t value = (int32_t) valp->numval;
+ if (value != 0)
+ __malloc_check_init ();
+}
-# define ptmalloc_unlock_all2 ptmalloc_unlock_all
-# endif
-#endif /* !NO_THREADS */
+# define TUNABLE_CALLBACK_FNDECL(__name, __type) \
+static inline int do_ ## __name (__type value); \
+void \
+TUNABLE_CALLBACK (__name) (tunable_val_t *valp) \
+{ \
+ __type value = (__type) (valp)->numval; \
+ do_ ## __name (value); \
+}
+TUNABLE_CALLBACK_FNDECL (set_mmap_threshold, size_t)
+TUNABLE_CALLBACK_FNDECL (set_mmaps_max, int32_t)
+TUNABLE_CALLBACK_FNDECL (set_top_pad, size_t)
+TUNABLE_CALLBACK_FNDECL (set_perturb_byte, int32_t)
+TUNABLE_CALLBACK_FNDECL (set_trim_threshold, size_t)
+TUNABLE_CALLBACK_FNDECL (set_arena_max, size_t)
+TUNABLE_CALLBACK_FNDECL (set_arena_test, size_t)
+#if USE_TCACHE
+TUNABLE_CALLBACK_FNDECL (set_tcache_max, size_t)
+TUNABLE_CALLBACK_FNDECL (set_tcache_count, size_t)
+TUNABLE_CALLBACK_FNDECL (set_tcache_unsorted_limit, size_t)
+#endif
+TUNABLE_CALLBACK_FNDECL (set_mxfast, size_t)
+#else
/* Initialization routine. */
#include <string.h>
extern char **_environ;
static char *
-internal_function
next_env_entry (char ***position)
{
char **current = *position;
return result;
}
+#endif
#ifdef SHARED
__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);
+ thread_arena = &main_arena;
+
+ malloc_init_state (&main_arena);
+
+#if HAVE_TUNABLES
+ TUNABLE_GET (check, int32_t, TUNABLE_CALLBACK (set_mallopt_check));
+ TUNABLE_GET (top_pad, size_t, TUNABLE_CALLBACK (set_top_pad));
+ TUNABLE_GET (perturb, int32_t, TUNABLE_CALLBACK (set_perturb_byte));
+ TUNABLE_GET (mmap_threshold, size_t, TUNABLE_CALLBACK (set_mmap_threshold));
+ TUNABLE_GET (trim_threshold, size_t, TUNABLE_CALLBACK (set_trim_threshold));
+ TUNABLE_GET (mmap_max, int32_t, TUNABLE_CALLBACK (set_mmaps_max));
+ TUNABLE_GET (arena_max, size_t, TUNABLE_CALLBACK (set_arena_max));
+ TUNABLE_GET (arena_test, size_t, TUNABLE_CALLBACK (set_arena_test));
+# if USE_TCACHE
+ TUNABLE_GET (tcache_max, size_t, TUNABLE_CALLBACK (set_tcache_max));
+ TUNABLE_GET (tcache_count, size_t, TUNABLE_CALLBACK (set_tcache_count));
+ TUNABLE_GET (tcache_unsorted_limit, size_t,
+ TUNABLE_CALLBACK (set_tcache_unsorted_limit));
+# endif
+ TUNABLE_GET (mxfast, size_t, TUNABLE_CALLBACK (set_mxfast));
+#else
const char *s = NULL;
if (__glibc_likely (_environ != NULL))
{
}
}
}
- if (s && s[0])
- {
- __libc_mallopt (M_CHECK_ACTION, (int) (s[0] - '0'));
- if (check_action != 0)
- __malloc_check_init ();
- }
+ if (s && s[0] != '\0' && s[0] != '0')
+ __malloc_check_init ();
+#endif
+
+#if HAVE_MALLOC_INIT_HOOK
void (*hook) (void) = atomic_forced_read (__malloc_initialize_hook);
if (hook != NULL)
(*hook)();
+#endif
__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
of the page size. */
static heap_info *
-internal_function
new_heap (size_t size, size_t top_pad)
{
size_t pagesize = GLRO (dl_pagesize);
} 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;
+ mchunkptr top_chunk = top (ar_ptr), p;
heap_info *prev_heap;
- long new_size, top_size, extra, prev_size, misalign;
+ long new_size, top_size, top_area, extra, prev_size, misalign;
/* Can this heap go away completely? */
while (top_chunk == chunk_at_offset (heap, sizeof (*heap)))
/* 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 */
+ assert (chunksize_nomask (p) == (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;
+ new_size += prev_size (p);
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);
+ unlink_chunk (ar_ptr, p);
}
assert (((unsigned long) ((char *) p + new_size) & (pagesz - 1)) == 0);
assert (((char *) p + new_size) == ((char *) heap + heap->size));
set_head (top_chunk, new_size | PREV_INUSE);
/*check_chunk(ar_ptr, top_chunk);*/
}
+
+ /* Uses similar logic for per-thread arenas as the main arena with systrim
+ and _int_free by preserving the top pad and rounding down to the nearest
+ page. */
top_size = chunksize (top_chunk);
- extra = (top_size - pad - MINSIZE - 1) & ~(pagesz - 1);
- if (extra < (long) pagesz)
+ if ((unsigned long)(top_size) <
+ (unsigned long)(mp_.trim_threshold))
+ return 0;
+
+ top_area = top_size - MINSIZE - 1;
+ if (top_area < 0 || (size_t) top_area <= pad)
+ return 0;
+
+ /* Release in pagesize units and round down to the nearest page. */
+ extra = ALIGN_DOWN(top_area - pad, pagesz);
+ if (extra == 0)
return 0;
/* Try to shrink. */
return 0;
ar_ptr->system_mem -= extra;
- arena_mem -= extra;
/* Success. Adjust top accordingly. */
set_head (top_chunk, (top_size - extra) | PREV_INUSE);
/* Create a new arena with initial size "size". */
+/* If REPLACED_ARENA is not NULL, detach it from this thread. Must be
+ called while free_list_lock is held. */
+static void
+detach_arena (mstate replaced_arena)
+{
+ if (replaced_arena != NULL)
+ {
+ assert (replaced_arena->attached_threads > 0);
+ /* The current implementation only detaches from main_arena in
+ case of allocation failure. This means that it is likely not
+ beneficial to put the arena on free_list even if the
+ reference count reaches zero. */
+ --replaced_arena->attached_threads;
+ }
+}
+
static mstate
_int_new_arena (size_t size)
{
}
a = h->ar_ptr = (mstate) (h + 1);
malloc_init_state (a);
+ a->attached_threads = 1;
/*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);
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);
+ mstate replaced_arena = thread_arena;
+ thread_arena = a;
+ __libc_lock_init (a->mutex);
- (void) mutex_lock (&list_lock);
+ __libc_lock_lock (list_lock);
/* Add the new arena to the global list. */
a->next = main_arena.next;
+ /* FIXME: The barrier is an attempt to synchronize with read access
+ in reused_arena, which does not acquire list_lock while
+ traversing the list. */
atomic_write_barrier ();
main_arena.next = a;
- (void) mutex_unlock (&list_lock);
+ __libc_lock_unlock (list_lock);
+
+ __libc_lock_lock (free_list_lock);
+ detach_arena (replaced_arena);
+ __libc_lock_unlock (free_list_lock);
+
+ /* Lock this arena. NB: Another thread may have been attached to
+ this arena because the arena is now accessible from the
+ main_arena.next list and could have been picked by reused_arena.
+ This can only happen for the last arena created (before the arena
+ limit is reached). At this point, some arena has to be attached
+ to two threads. We could acquire the arena lock before list_lock
+ to make it less likely that reused_arena picks this new arena,
+ but this could result in a deadlock with
+ __malloc_fork_lock_parent. */
+
+ __libc_lock_lock (a->mutex);
return a;
}
+/* Remove an arena from free_list. */
static mstate
get_free_list (void)
{
+ mstate replaced_arena = thread_arena;
mstate result = free_list;
if (result != NULL)
{
- (void) mutex_lock (&list_lock);
+ __libc_lock_lock (free_list_lock);
result = free_list;
if (result != NULL)
- free_list = result->next_free;
- (void) mutex_unlock (&list_lock);
+ {
+ free_list = result->next_free;
+
+ /* The arena will be attached to this thread. */
+ assert (result->attached_threads == 0);
+ result->attached_threads = 1;
+
+ detach_arena (replaced_arena);
+ }
+ __libc_lock_unlock (free_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);
+ __libc_lock_lock (result->mutex);
+ thread_arena = result;
}
}
return result;
}
+/* Remove the arena from the free list (if it is present).
+ free_list_lock must have been acquired by the caller. */
+static void
+remove_from_free_list (mstate arena)
+{
+ mstate *previous = &free_list;
+ for (mstate p = free_list; p != NULL; p = p->next_free)
+ {
+ assert (p->attached_threads == 0);
+ if (p == arena)
+ {
+ /* Remove the requested arena from the list. */
+ *previous = p->next_free;
+ break;
+ }
+ else
+ previous = &p->next_free;
+ }
+}
+
/* 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. */
reused_arena (mstate avoid_arena)
{
mstate result;
+ /* FIXME: Access to next_to_use suffers from data races. */
static mstate next_to_use;
if (next_to_use == NULL)
next_to_use = &main_arena;
+ /* Iterate over all arenas (including those linked from
+ free_list). */
result = next_to_use;
do
{
- if (!mutex_trylock (&result->mutex))
+ if (!__libc_lock_trylock (result->mutex))
goto out;
+ /* FIXME: This is a data race, see _int_new_arena. */
result = result->next;
}
while (result != next_to_use);
if (result == avoid_arena)
result = result->next;
- /* No arena available. Wait for the next in line. */
+ /* No arena available without contention. Wait for the next in line. */
LIBC_PROBE (memory_arena_reuse_wait, 3, &result->mutex, result, avoid_arena);
- (void) mutex_lock (&result->mutex);
+ __libc_lock_lock (result->mutex);
out:
+ /* Attach the arena to the current thread. */
+ {
+ /* Update the arena thread attachment counters. */
+ mstate replaced_arena = thread_arena;
+ __libc_lock_lock (free_list_lock);
+ detach_arena (replaced_arena);
+
+ /* We may have picked up an arena on the free list. We need to
+ preserve the invariant that no arena on the free list has a
+ positive attached_threads counter (otherwise,
+ arena_thread_freeres cannot use the counter to determine if the
+ arena needs to be put on the free list). We unconditionally
+ remove the selected arena from the free list. The caller of
+ reused_arena checked the free list and observed it to be empty,
+ so the list is very short. */
+ remove_from_free_list (result);
+
+ ++result->attached_threads;
+
+ __libc_lock_unlock (free_list_lock);
+ }
+
LIBC_PROBE (memory_arena_reuse, 2, result, avoid_arena);
- tsd_setspecific (arena_key, (void *) result);
+ thread_arena = result;
next_to_use = result->next;
return result;
}
static mstate
-internal_function
-arena_get2 (mstate a_tsd, size_t size, mstate avoid_arena)
+arena_get2 (size_t size, mstate avoid_arena)
{
mstate a;
LIBC_PROBE (memory_arena_retry, 2, bytes, ar_ptr);
if (ar_ptr != &main_arena)
{
- (void) mutex_unlock (&ar_ptr->mutex);
+ __libc_lock_unlock (ar_ptr->mutex);
ar_ptr = &main_arena;
- (void) mutex_lock (&ar_ptr->mutex);
+ __libc_lock_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);
+ __libc_lock_unlock (ar_ptr->mutex);
+ ar_ptr = arena_get2 (bytes, ar_ptr);
}
return ar_ptr;
}
-static void __attribute__ ((section ("__libc_thread_freeres_fn")))
-arena_thread_freeres (void)
+void
+__malloc_arena_thread_freeres (void)
{
- void *vptr = NULL;
- mstate a = tsd_getspecific (arena_key, vptr);
- tsd_setspecific (arena_key, NULL);
+ /* Shut down the thread cache first. This could deallocate data for
+ the thread arena, so do this before we put the arena on the free
+ list. */
+ tcache_thread_shutdown ();
+
+ mstate a = thread_arena;
+ thread_arena = NULL;
if (a != NULL)
{
- (void) mutex_lock (&list_lock);
- a->next_free = free_list;
- free_list = a;
- (void) mutex_unlock (&list_lock);
+ __libc_lock_lock (free_list_lock);
+ /* If this was the last attached thread for this arena, put the
+ arena on the free list. */
+ assert (a->attached_threads > 0);
+ if (--a->attached_threads == 0)
+ {
+ a->next_free = free_list;
+ free_list = a;
+ }
+ __libc_lock_unlock (free_list_lock);
}
}
-text_set_element (__libc_thread_subfreeres, arena_thread_freeres);
/*
* Local variables:
projects / thirdparty / glibc.git / blobdiff