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Hi,
The patch below contains a few cleanups and fixes for malloc. It
looks rather large, but in reality the changes are not _that_ big.
I've also tested this version quite extensively already, so I'd like
it to go into 2.1.3 if possible. (I plan to make a new stand-alone
release as well.)
The support for multiple arenas has been decoupled from threads
support. This is so on large-memory machines, if sbrk() fails due to
address space limitations, an mmap()ed arena is created if possible to
serve a malloc request anyway.
A recently discovered failure involving very large allocations as the
very first thing from a concurrent thread is fixed.
Regards,
Wolfram.
1999-12-05 Wolfram Gloger <wg@malloc.de>
* malloc/malloc.c (arena_get2): If generating a new arena fails,
try to generate a minimal one and hope for mmap_chunk() to succeed
later.
1999-11-07 Wolfram Gloger <wg@malloc.de>
* malloc/thread-m.h [NO_THREADS]: The mutex_* macros now let
mutex_t work as an `in-use' flag even without threads.
* malloc/malloc.c (USE_ARENAS): New feature flag, controls support
for multiple arenas separately from NO_THREADS.
(mALLOc, chunk_realloc, mEMALIGn, cALLOc) [USE_ARENAS]: try to
fall back to an mmap()ed arena when sbrk() has failed.
--- thread-m.h.orig Thu Dec 31 19:08:27 1998
+++ thread-m.h Wed Dec 8 23:35:58 1999
@@ -207,18 +207,24 @@
typedef int thread_id;
+/* The mutex functions used to do absolutely nothing, i.e. lock,
+ trylock and unlock would always just return 0. However, even
+ without any concurrently active threads, a mutex can be used
+ legitimately as an `in use' flag. To make the code that is
+ protected by a mutex async-signal safe, these macros would have to
+ be based on atomic test-and-set operations, for example. */
typedef int mutex_t;
#define MUTEX_INITIALIZER 0
#define mutex_init(m) (*(m) = 0)
-#define mutex_lock(m) (0)
-#define mutex_trylock(m) (0)
-#define mutex_unlock(m) (0)
+#define mutex_lock(m) ((*(m) = 1), 0)
+#define mutex_trylock(m) (*(m) ? 1 : ((*(m) = 1), 0))
+#define mutex_unlock(m) (*(m) = 0)
typedef void *tsd_key_t;
#define tsd_key_create(key, destr) do {} while(0)
-#define tsd_setspecific(key, data) do {} while(0)
-#define tsd_getspecific(key, vptr) (vptr = NULL)
+#define tsd_setspecific(key, data) ((key) = (data))
+#define tsd_getspecific(key, vptr) (vptr = (key))
#define thread_atfork(prepare, parent, child) do {} while(0)
--- malloc.c.orig Sat Sep 25 08:35:58 1999
+++ malloc.c Wed Dec 8 23:41:56 1999
@@ -19,7 +19,7 @@
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
-/* V2.6.4-pt3 Thu Feb 20 1997
+/* $Id: ptmalloc.c,v 1.1.1.15 1999/12/06 11:21:04 wmglo Exp $
This work is mainly derived from malloc-2.6.4 by Doug Lea
<dl@cs.oswego.edu>, which is available from:
@@ -202,6 +202,8 @@
HAVE_MREMAP (default: defined as 0 unless Linux libc set)
Define to non-zero to optionally make realloc() use mremap() to
reallocate very large blocks.
+ USE_ARENAS (default: the same as HAVE_MMAP)
+ Enable support for multiple arenas, allocated using mmap().
malloc_getpagesize (default: derived from system #includes)
Either a constant or routine call returning the system page size.
HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
@@ -307,6 +309,9 @@
# endif
#else
# include <sys/types.h>
+# if defined _LIBC || defined MALLOC_HOOKS
+extern char* getenv();
+# endif
#endif
#ifndef _LIBC
@@ -508,9 +513,10 @@
#endif
/*
- Define HAVE_MMAP to optionally make malloc() use mmap() to
- allocate very large blocks. These will be returned to the
- operating system immediately after a free().
+ Define HAVE_MMAP to optionally make malloc() use mmap() to allocate
+ very large blocks. These will be returned to the operating system
+ immediately after a free(). HAVE_MMAP is also a prerequisite to
+ support multiple `arenas' (see USE_ARENAS below).
*/
#ifndef HAVE_MMAP
@@ -529,6 +535,15 @@
#define HAVE_MREMAP defined(__linux__) && !defined(__arm__)
#endif
+/* Define USE_ARENAS to enable support for multiple `arenas'. These
+ are allocated using mmap(), are necessary for threads and
+ occasionally useful to overcome address space limitations affecting
+ sbrk(). */
+
+#ifndef USE_ARENAS
+#define USE_ARENAS HAVE_MMAP
+#endif
+
#if HAVE_MMAP
#include <unistd.h>
@@ -987,12 +1002,15 @@
#ifdef __cplusplus
-}; /* end of extern "C" */
+} /* end of extern "C" */
#endif
#if !defined(NO_THREADS) && !HAVE_MMAP
"Can't have threads support without mmap"
#endif
+#if USE_ARENAS && !HAVE_MMAP
+"Can't have multiple arenas without mmap"
+#endif
/*
@@ -1193,8 +1211,8 @@
/* 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. Not used unless compiling for
- multiple threads. */
+ address aligned to HEAP_MAX_SIZE. Not used unless compiling with
+ USE_ARENAS. */
typedef struct _heap_info {
arena *ar_ptr; /* Arena for this heap. */
@@ -1219,7 +1237,7 @@
static mchunkptr chunk_align(arena *ar_ptr, INTERNAL_SIZE_T nb,
size_t alignment) internal_function;
static int main_trim(size_t pad) internal_function;
-#ifndef NO_THREADS
+#if USE_ARENAS
static int heap_trim(heap_info *heap, size_t pad) internal_function;
#endif
#if defined _LIBC || defined MALLOC_HOOKS
@@ -1244,7 +1262,7 @@
static mchunkptr chunk_realloc();
static mchunkptr chunk_align();
static int main_trim();
-#ifndef NO_THREADS
+#if USE_ARENAS
static int heap_trim();
#endif
#if defined _LIBC || defined MALLOC_HOOKS
@@ -1511,10 +1529,8 @@
/* Thread specific data */
-#ifndef NO_THREADS
static tsd_key_t arena_key;
static mutex_t list_lock = MUTEX_INITIALIZER;
-#endif
#if THREAD_STATS
static int stat_n_heaps = 0;
@@ -1552,6 +1568,9 @@
static unsigned long mmapped_mem = 0;
static unsigned long max_mmapped_mem = 0;
+/* Mapped memory in non-main arenas (reliable only for NO_THREADS). */
+static unsigned long arena_mem = 0;
+
#ifndef _LIBC
@@ -1656,7 +1675,11 @@
#endif
{
#if defined _LIBC || defined MALLOC_HOOKS
+# if __STD_C
const char* s;
+# else
+ char* s;
+# endif
#endif
if(__malloc_initialized >= 0) return;
@@ -1679,12 +1702,12 @@
if (__pthread_initialize != NULL)
__pthread_initialize();
#endif
+#endif /* !defined NO_THREADS */
mutex_init(&main_arena.mutex);
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_init_all);
-#endif /* !defined NO_THREADS */
#if defined _LIBC || defined MALLOC_HOOKS
if((s = __secure_getenv("MALLOC_TRIM_THRESHOLD_")))
mALLOPt(M_TRIM_THRESHOLD, atoi(s));
@@ -1836,7 +1859,7 @@
#if defined __GNUC__ && __GNUC__ >= 2
/* This function is only called from one place, inline it. */
-inline
+__inline__
#endif
static mchunkptr
internal_function
@@ -1876,8 +1899,8 @@
if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
max_mmapped_mem = mmapped_mem;
#ifdef NO_THREADS
- if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
- max_total_mem = mmapped_mem + sbrked_mem;
+ if ((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem)
+ max_total_mem = mmapped_mem + arena_mem + sbrked_mem;
#endif
return p;
}
@@ -1947,8 +1970,8 @@
if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
max_mmapped_mem = mmapped_mem;
#ifdef NO_THREADS
- if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
- max_total_mem = mmapped_mem + sbrked_mem;
+ if ((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem)
+ max_total_mem = mmapped_mem + arena_mem + sbrked_mem;
#endif
return p;
}
@@ -1961,7 +1984,7 @@
/* Managing heaps and arenas (for concurrent threads) */
-#ifndef NO_THREADS
+#if USE_ARENAS
/* Create a new heap. size is automatically rounded up to a multiple
of the page size. */
@@ -2037,7 +2060,7 @@
/* 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)
+ MAP_PRIVATE|MAP_FIXED) == (char *) MAP_FAILED)
return -2;
}
h->size = new_size;
@@ -2052,7 +2075,9 @@
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. */
+ 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 { \
Void_t *vptr = NULL; \
@@ -2112,13 +2137,24 @@
/* Nothing immediately available, so generate a new arena. */
h = new_heap(size + (sizeof(*h) + sizeof(*a) + MALLOC_ALIGNMENT));
- if(!h)
- return 0;
+ if(!h) {
+ /* Maybe size is too large to fit in a single heap. So, just try
+ to create a minimally-sized arena and let chunk_alloc() attempt
+ to deal with the large request via mmap_chunk(). */
+ h = new_heap(sizeof(*h) + sizeof(*a) + MALLOC_ALIGNMENT);
+ if(!h)
+ return 0;
+ }
a = h->ar_ptr = (arena *)(h+1);
for(i=0; i<NAV; i++)
init_bin(a, i);
a->next = NULL;
a->size = h->size;
+ arena_mem += h->size;
+#ifdef NO_THREADS
+ if((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem)
+ max_total_mem = mmapped_mem + arena_mem + sbrked_mem;
+#endif
tsd_setspecific(arena_key, (Void_t *)a);
mutex_init(&a->mutex);
i = mutex_lock(&a->mutex); /* remember result */
@@ -2152,14 +2188,14 @@
(((mchunkptr)(ptr) < top(&main_arena) && (char *)(ptr) >= sbrk_base) ? \
&main_arena : heap_for_ptr(ptr)->ar_ptr)
-#else /* defined(NO_THREADS) */
+#else /* !USE_ARENAS */
-/* Without concurrent threads, there is only one arena. */
+/* There is only one arena, main_arena. */
#define arena_get(ptr, sz) (ptr = &main_arena)
#define arena_for_ptr(ptr) (&main_arena)
-#endif /* !defined(NO_THREADS) */
+#endif /* USE_ARENAS */
@@ -2189,7 +2225,7 @@
/* No checkable chunk is mmapped */
assert(!chunk_is_mmapped(p));
-#ifndef NO_THREADS
+#if USE_ARENAS
if(ar_ptr != &main_arena) {
heap_info *heap = heap_for_ptr(p);
assert(heap->ar_ptr == ar_ptr);
@@ -2397,7 +2433,7 @@
#if defined __GNUC__ && __GNUC__ >= 2
/* This function is called only from one place, inline it. */
-inline
+__inline__
#endif
static void
internal_function
@@ -2412,7 +2448,7 @@
INTERNAL_SIZE_T old_top_size = chunksize(old_top);
INTERNAL_SIZE_T top_size; /* new size of top chunk */
-#ifndef NO_THREADS
+#if USE_ARENAS
if(ar_ptr == &main_arena) {
#endif
@@ -2492,12 +2528,11 @@
if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem)
max_sbrked_mem = sbrked_mem;
#ifdef NO_THREADS
- if ((unsigned long)(mmapped_mem + sbrked_mem) >
- (unsigned long)max_total_mem)
- max_total_mem = mmapped_mem + sbrked_mem;
+ if ((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem)
+ max_total_mem = mmapped_mem + arena_mem + sbrked_mem;
#endif
-#ifndef NO_THREADS
+#if USE_ARENAS
} else { /* ar_ptr != &main_arena */
heap_info *old_heap, *heap;
size_t old_heap_size;
@@ -2512,6 +2547,11 @@
old_heap_size = old_heap->size;
if(grow_heap(old_heap, MINSIZE + nb - old_top_size) == 0) {
ar_ptr->size += old_heap->size - old_heap_size;
+ arena_mem += old_heap->size - old_heap_size;
+#ifdef NO_THREADS
+ if(mmapped_mem + arena_mem + sbrked_mem > max_total_mem)
+ max_total_mem = mmapped_mem + arena_mem + sbrked_mem;
+#endif
top_size = ((char *)old_heap + old_heap->size) - (char *)old_top;
set_head(old_top, top_size | PREV_INUSE);
return;
@@ -2524,13 +2564,18 @@
heap->ar_ptr = ar_ptr;
heap->prev = old_heap;
ar_ptr->size += heap->size;
+ arena_mem += heap->size;
+#ifdef NO_THREADS
+ if((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem)
+ max_total_mem = mmapped_mem + arena_mem + sbrked_mem;
+#endif
/* Set up the new top, so we can safely use chunk_free() below. */
top(ar_ptr) = chunk_at_offset(heap, sizeof(*heap));
top_size = heap->size - sizeof(*heap);
set_head(top(ar_ptr), top_size | PREV_INUSE);
}
-#endif /* !defined(NO_THREADS) */
+#endif /* USE_ARENAS */
/* We always land on a page boundary */
assert(((unsigned long)((char*)top(ar_ptr) + top_size) & (pagesz-1)) == 0);
@@ -2649,16 +2694,27 @@
if(!ar_ptr)
return 0;
victim = chunk_alloc(ar_ptr, nb);
- (void)mutex_unlock(&ar_ptr->mutex);
if(!victim) {
/* Maybe the failure is due to running out of mmapped areas. */
if(ar_ptr != &main_arena) {
+ (void)mutex_unlock(&ar_ptr->mutex);
(void)mutex_lock(&main_arena.mutex);
victim = chunk_alloc(&main_arena, nb);
(void)mutex_unlock(&main_arena.mutex);
+ } else {
+#if USE_ARENAS
+ /* ... or sbrk() has failed and there is still a chance to mmap() */
+ ar_ptr = arena_get2(ar_ptr->next ? ar_ptr : 0, nb);
+ (void)mutex_unlock(&main_arena.mutex);
+ if(ar_ptr) {
+ victim = chunk_alloc(ar_ptr, nb);
+ (void)mutex_unlock(&ar_ptr->mutex);
+ }
+#endif
}
if(!victim) return 0;
- }
+ } else
+ (void)mutex_unlock(&ar_ptr->mutex);
return chunk2mem(victim);
}
@@ -2999,7 +3055,7 @@
if (!(hd & PREV_INUSE)) /* consolidate backward */
{
prevsz = p->prev_size;
- p = chunk_at_offset(p, -prevsz);
+ p = chunk_at_offset(p, -(long)prevsz);
sz += prevsz;
unlink(p, bck, fwd);
}
@@ -3007,12 +3063,12 @@
set_head(p, sz | PREV_INUSE);
top(ar_ptr) = p;
-#ifndef NO_THREADS
+#if USE_ARENAS
if(ar_ptr == &main_arena) {
#endif
if ((unsigned long)(sz) >= (unsigned long)trim_threshold)
main_trim(top_pad);
-#ifndef NO_THREADS
+#if USE_ARENAS
} else {
heap_info *heap = heap_for_ptr(p);
@@ -3032,7 +3088,7 @@
if (!(hd & PREV_INUSE)) /* consolidate backward */
{
prevsz = p->prev_size;
- p = chunk_at_offset(p, -prevsz);
+ p = chunk_at_offset(p, -(long)prevsz);
sz += prevsz;
if (p->fd == last_remainder(ar_ptr)) /* keep as last_remainder */
@@ -3064,7 +3120,7 @@
if (!islr)
frontlink(ar_ptr, p, sz, idx, bck, fwd);
-#ifndef NO_THREADS
+#if USE_ARENAS
/* Check whether the heap containing top can go away now. */
if(next->size < MINSIZE &&
(unsigned long)sz > trim_threshold &&
@@ -3325,6 +3381,15 @@
(void)mutex_lock(&main_arena.mutex);
newp = chunk_alloc(&main_arena, nb);
(void)mutex_unlock(&main_arena.mutex);
+ } else {
+#if USE_ARENAS
+ /* ... or sbrk() has failed and there is still a chance to mmap() */
+ arena* ar_ptr2 = arena_get2(ar_ptr->next ? ar_ptr : 0, nb);
+ if(ar_ptr2) {
+ newp = chunk_alloc(ar_ptr2, nb);
+ (void)mutex_unlock(&ar_ptr2->mutex);
+ }
+#endif
}
if (newp == 0) /* propagate failure */
return 0;
@@ -3435,6 +3500,15 @@
(void)mutex_lock(&main_arena.mutex);
p = chunk_align(&main_arena, nb, alignment);
(void)mutex_unlock(&main_arena.mutex);
+ } else {
+#if USE_ARENAS
+ /* ... or sbrk() has failed and there is still a chance to mmap() */
+ ar_ptr = arena_get2(ar_ptr->next ? ar_ptr : 0, nb);
+ if(ar_ptr) {
+ p = chunk_align(ar_ptr, nb, alignment);
+ (void)mutex_unlock(&ar_ptr->mutex);
+ }
+#endif
}
if(!p) return 0;
}
@@ -3464,7 +3538,7 @@
if (p == 0)
return 0; /* propagate failure */
- m = chunk2mem(p);
+ m = (char*)chunk2mem(p);
if ((((unsigned long)(m)) % alignment) == 0) /* aligned */
{
@@ -3485,7 +3559,8 @@
this is always possible.
*/
- brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -alignment);
+ brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) &
+ -(long)alignment);
if ((long)(brk - (char*)(p)) < (long)MINSIZE) brk += alignment;
newp = (mchunkptr)brk;
@@ -3611,7 +3686,8 @@
oldtopsize = chunksize(top(ar_ptr));
#if MORECORE_CLEARS < 2
/* Only newly allocated memory is guaranteed to be cleared. */
- if (oldtopsize < sbrk_base + max_sbrked_mem - (char *)oldtop)
+ if (ar_ptr == &main_arena &&
+ oldtopsize < sbrk_base + max_sbrked_mem - (char *)oldtop)
oldtopsize = (sbrk_base + max_sbrked_mem - (char *)oldtop);
#endif
#endif
@@ -3626,6 +3702,17 @@
(void)mutex_lock(&main_arena.mutex);
p = chunk_alloc(&main_arena, sz);
(void)mutex_unlock(&main_arena.mutex);
+ } else {
+#if USE_ARENAS
+ /* ... or sbrk() has failed and there is still a chance to mmap() */
+ (void)mutex_lock(&main_arena.mutex);
+ ar_ptr = arena_get2(ar_ptr->next ? ar_ptr : 0, sz);
+ (void)mutex_unlock(&main_arena.mutex);
+ if(ar_ptr) {
+ p = chunk_alloc(ar_ptr, sz);
+ (void)mutex_unlock(&ar_ptr->mutex);
+ }
+#endif
}
if (p == 0) return 0;
}
@@ -3664,7 +3751,7 @@
void cfree(mem) Void_t *mem;
#endif
{
- free(mem);
+ fREe(mem);
}
#endif
@@ -3765,7 +3852,7 @@
return 1;
}
-#ifndef NO_THREADS
+#if USE_ARENAS
static int
internal_function
@@ -3795,6 +3882,7 @@
if(new_size + (HEAP_MAX_SIZE - prev_heap->size) < pad + MINSIZE + pagesz)
break;
ar_ptr->size -= heap->size;
+ arena_mem -= heap->size;
delete_heap(heap);
heap = prev_heap;
if(!prev_inuse(p)) { /* consolidate backward */
@@ -3815,6 +3903,7 @@
if(grow_heap(heap, -extra) != 0)
return 0;
ar_ptr->size -= extra;
+ arena_mem -= extra;
/* Success. Adjust top accordingly. */
set_head(top_chunk, (top_size - extra) | PREV_INUSE);
@@ -3822,7 +3911,7 @@
return 1;
}
-#endif
+#endif /* USE_ARENAS */
@@ -3913,7 +4002,7 @@
(void)mutex_unlock(&ar_ptr->mutex);
}
-#if !defined(NO_THREADS) && MALLOC_DEBUG > 1
+#if USE_ARENAS && MALLOC_DEBUG > 1
/* Print the complete contents of a single heap to stderr. */
@@ -3989,7 +4078,7 @@
stat_lock_loop += ar_ptr->stat_lock_loop;
stat_lock_wait += ar_ptr->stat_lock_wait;
#endif
-#if !defined(NO_THREADS) && MALLOC_DEBUG > 1
+#if USE_ARENAS && MALLOC_DEBUG > 1
if(ar_ptr != &main_arena) {
heap_info *heap;
(void)mutex_lock(&ar_ptr->mutex);
@@ -4071,7 +4160,7 @@
case M_TOP_PAD:
top_pad = value; return 1;
case M_MMAP_THRESHOLD:
-#ifndef NO_THREADS
+#if USE_ARENAS
/* Forbid setting the threshold too high. */
if((unsigned long)value > HEAP_MAX_SIZE/2) return 0;
#endif
@@ -4128,7 +4217,7 @@
unsigned int max_n_mmaps;
unsigned long mmapped_mem;
unsigned long max_mmapped_mem;
- int using_malloc_checking;
+ int using_malloc_checking;
};
Void_t*
@@ -4237,7 +4326,7 @@
/* Check whether it is safe to enable malloc checking, or whether
it is necessary to disable it. */
if (ms->using_malloc_checking && !using_malloc_checking &&
- !disallow_malloc_check)
+ !disallow_malloc_check)
__malloc_check_init ();
else if (!ms->using_malloc_checking && using_malloc_checking) {
__malloc_hook = 0;
@@ -4456,9 +4545,9 @@
oldp = mem2chunk_check(oldmem);
if(!oldp) {
(void)mutex_unlock(&main_arena.mutex);
- if (check_action & 1)
+ if(check_action & 1)
fprintf(stderr, "realloc(): invalid pointer %p!\n", oldmem);
- if (check_action & 2)
+ if(check_action & 2)
abort();
return malloc_check(bytes, NULL);
}
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