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-rw-r--r--malloc/arena.c179
1 files changed, 119 insertions, 60 deletions
diff --git a/malloc/arena.c b/malloc/arena.c
index 026f2c7822..0dcb7cb9f8 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 */
/*