* This file is subject to the terms and conditions of the GNU Lesser
* General Public License. See the file COPYING.LIB in the main
* directory of this archive for more details.
- *
+ *
* Written by Miles Bader <miles@gnu.org>
*/
/* The alignment we guarantee for malloc return values. */
#define MALLOC_ALIGNMENT (sizeof (double))
-/* The system pagesize we assume; we really ought to get it with
- getpagesize, but gee, how annoying. */
-#define MALLOC_PAGE_SIZE 4096
+/* The system pagesize... */
+extern size_t __pagesize;
+libc_hidden_proto(__pagesize)
+#define MALLOC_PAGE_SIZE __pagesize
/* The minimum size of block we request from the the system to extend the
heap for small allocations (we may request a bigger block if necessary to
MALLOC_MIN_SIZE, will cause us not to reserve anything. */
#define MALLOC_MIN_SIZE (2*MALLOC_PAGE_SIZE)
+/* When realloc shrinks an allocation, it only does so if more than this
+ many bytes will be freed; it must at at least HEAP_MIN_SIZE. Larger
+ values increase speed (by reducing heap fragmentation) at the expense of
+ space. */
+#define MALLOC_REALLOC_MIN_FREE_SIZE (HEAP_MIN_SIZE + 16)
+
/* For systems with an MMU, use sbrk to map/unmap memory for the malloc
heap, instead of mmap/munmap. This is a tradeoff -- sbrk is faster than
mmap/munmap, and guarantees contiguous allocation, but is also less
flexible, and causes the heap to only be shrinkable from the end. */
-#ifdef __UCLIBC_HAS_MMU__
+#ifdef __ARCH_HAS_MMU__
# define MALLOC_USE_SBRK
#endif
+/* The current implementation of munmap in uClinux doesn't work correctly:
+ it requires that ever call to munmap exactly match a corresponding call
+ to mmap (that is, it doesn't allow you to unmap only part of a
+ previously allocated block, or to unmap two contiguous blocks with a
+ single call to munmap). This behavior is broken, and uClinux should be
+ fixed; however, until it is, we add code to work around the problem in
+ malloc. */
+#ifdef __UCLIBC_UCLINUX_BROKEN_MUNMAP__
+
+/* A structure recording a block of memory mmapped by malloc. */
+struct malloc_mmb
+{
+ void *mem; /* the mmapped block */
+ size_t size; /* its size */
+ struct malloc_mmb *next;
+};
+
+/* A list of all malloc_mmb structures describing blocsk that malloc has
+ mmapped, ordered by the block address. */
+extern struct malloc_mmb *__malloc_mmapped_blocks;
+
+/* A heap used for allocating malloc_mmb structures. We could allocate
+ them from the main heap, but that tends to cause heap fragmentation in
+ annoying ways. */
+extern struct heap __malloc_mmb_heap;
+
+/* Define MALLOC_MMB_DEBUGGING to cause malloc to emit debugging info about
+ about mmap block allocation/freeing by the `uclinux broken munmap' code
+ to stderr, when the variable __malloc_mmb_debug is set to true. */
+#ifdef MALLOC_MMB_DEBUGGING
+# include <stdio.h>
+extern int __putc(int c, FILE *stream) attribute_hidden;
+
+extern int __malloc_mmb_debug;
+# define MALLOC_MMB_DEBUG(indent, fmt, args...) \
+ (__malloc_mmb_debug ? __malloc_debug_printf (indent, fmt , ##args) : 0)
+# define MALLOC_MMB_DEBUG_INDENT(indent) \
+ (__malloc_mmb_debug ? __malloc_debug_indent (indent) : 0)
+# ifndef MALLOC_DEBUGGING
+# define MALLOC_DEBUGGING
+# endif
+#else /* !MALLOC_MMB_DEBUGGING */
+# define MALLOC_MMB_DEBUG(fmt, args...) (void)0
+# define MALLOC_MMB_DEBUG_INDENT(indent) (void)0
+#endif /* MALLOC_MMB_DEBUGGING */
+
+#endif /* __UCLIBC_UCLINUX_BROKEN_MUNMAP__ */
+
+
+/* The size of a malloc allocation is stored in a size_t word
+ MALLOC_ALIGNMENT bytes prior to the start address of the allocation:
+
+ +--------+---------+-------------------+
+ | SIZE |(unused) | allocation ... |
+ +--------+---------+-------------------+
+ ^ BASE ^ ADDR
+ ^ ADDR - MALLOC_ALIGN
+*/
+
+/* The amount of extra space used by the malloc header. */
+#define MALLOC_HEADER_SIZE MALLOC_ALIGNMENT
+
+/* Set up the malloc header, and return the user address of a malloc block. */
+#define MALLOC_SETUP(base, size) \
+ (MALLOC_SET_SIZE (base, size), (void *)((char *)base + MALLOC_HEADER_SIZE))
+/* Set the size of a malloc allocation, given the base address. */
+#define MALLOC_SET_SIZE(base, size) (*(size_t *)(base) = (size))
+
+/* Return base-address of a malloc allocation, given the user address. */
+#define MALLOC_BASE(addr) ((void *)((char *)addr - MALLOC_HEADER_SIZE))
+/* Return the size of a malloc allocation, given the user address. */
+#define MALLOC_SIZE(addr) (*(size_t *)MALLOC_BASE(addr))
+
+
+/* Locking for multithreaded apps. */
#ifdef __UCLIBC_HAS_THREADS__
# include <pthread.h>
typedef pthread_mutex_t malloc_mutex_t;
# define MALLOC_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
-/* The main malloc lock. This must be hold while accessing __malloc_heap,
- and in order to gain __malloc_sbrk_lock. */
-extern malloc_mutex_t __malloc_lock;
-# define __malloc_lock() pthread_mutex_lock (&__malloc_lock)
-# define __malloc_unlock() pthread_mutex_unlock (&__malloc_lock)
-
# ifdef MALLOC_USE_SBRK
/* This lock is used to serialize uses of the `sbrk' function (in both
malloc and free, sbrk may be used several times in succession, and
things will break if these multiple calls are interleaved with another
thread's use of sbrk!). */
extern malloc_mutex_t __malloc_sbrk_lock;
-# define __malloc_lock_sbrk() pthread_mutex_lock (&__malloc_sbrk_lock)
-# define __malloc_unlock_sbrk() pthread_mutex_unlock (&__malloc_sbrk_lock)
+# define __malloc_lock_sbrk() __pthread_mutex_lock (&__malloc_sbrk_lock)
+# define __malloc_unlock_sbrk() __pthread_mutex_unlock (&__malloc_sbrk_lock)
# endif /* MALLOC_USE_SBRK */
#else /* !__UCLIBC_HAS_THREADS__ */
/* Without threads, mutex operations are a nop. */
-# define __malloc_lock() (void)0
-# define __malloc_unlock() (void)0
# define __malloc_lock_sbrk() (void)0
# define __malloc_unlock_sbrk() (void)0
#endif /* __UCLIBC_HAS_THREADS__ */
-/* Change this to `#if 1' to cause malloc to emit debugging info to stderr. */
-#if 0
-#include <stdio.h>
-#define MALLOC_DEBUG(fmt, args...) fprintf (stderr, fmt , ##args)
+/* branch-prediction macros; they may already be defined by libc. */
+#ifndef likely
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
+#define likely(cond) __builtin_expect(!!(int)(cond), 1)
+#define unlikely(cond) __builtin_expect((int)(cond), 0)
#else
-#define MALLOC_DEBUG(fmt, args...) (void)0
+#define likely(cond) (cond)
+#define unlikely(cond) (cond)
#endif
+#endif /* !likely */
+
+
+/* Define MALLOC_DEBUGGING to cause malloc to emit debugging info to stderr
+ when the variable __malloc_debug is set to true. */
+#ifdef MALLOC_DEBUGGING
+
+extern void __malloc_debug_init (void);
+
+/* The number of spaces in a malloc debug indent level. */
+#define MALLOC_DEBUG_INDENT_SIZE 3
+
+extern int __malloc_debug, __malloc_check;
+
+# define MALLOC_DEBUG(indent, fmt, args...) \
+ (__malloc_debug ? __malloc_debug_printf (indent, fmt , ##args) : 0)
+# define MALLOC_DEBUG_INDENT(indent) \
+ (__malloc_debug ? __malloc_debug_indent (indent) : 0)
+
+extern int __malloc_debug_cur_indent;
+
+/* Print FMT and args indented at the current debug print level, followed
+ by a newline, and change the level by INDENT. */
+extern void __malloc_debug_printf (int indent, const char *fmt, ...);
+
+/* Change the current debug print level by INDENT, and return the value. */
+#define __malloc_debug_indent(indent) (__malloc_debug_cur_indent += indent)
+
+/* Set the current debug print level to LEVEL. */
+#define __malloc_debug_set_indent(level) (__malloc_debug_cur_indent = level)
+
+#else /* !MALLOC_DEBUGGING */
+# define MALLOC_DEBUG(fmt, args...) (void)0
+# define MALLOC_DEBUG_INDENT(indent) (void)0
+#endif /* MALLOC_DEBUGGING */
/* Return SZ rounded down to POWER_OF_2_SIZE (which must be power of 2). */
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