1 /* 2 * malloc.h 3 * 4 * Internals for the memory allocator 5 */ 6 7 #include <stdint.h> 8 #include <stddef.h> 9 10 /* 11 * This is the minimum chunk size we will ask the kernel for; this should 12 * be a multiple of the page size on all architectures. 13 */ 14 #define MALLOC_CHUNK_SIZE 65536 15 #define MALLOC_CHUNK_MASK (MALLOC_CHUNK_SIZE-1) 16 17 /* 18 * This structure should be a power of two. This becomes the 19 * alignment unit. 20 */ 21 struct free_arena_header; 22 23 struct arena_header { 24 size_t type; 25 size_t size; /* Also gives the location of the next entry */ 26 struct free_arena_header *next, *prev; 27 }; 28 29 #ifdef DEBUG_MALLOC 30 #define ARENA_TYPE_USED 0x64e69c70 31 #define ARENA_TYPE_FREE 0x012d610a 32 #define ARENA_TYPE_HEAD 0x971676b5 33 #define ARENA_TYPE_DEAD 0xeeeeeeee 34 #else 35 #define ARENA_TYPE_USED 0 36 #define ARENA_TYPE_FREE 1 37 #define ARENA_TYPE_HEAD 2 38 #endif 39 40 #define ARENA_SIZE_MASK (sizeof(struct arena_header)-1) 41 42 #define ARENA_ALIGN_UP(p) ((char *)(((uintptr_t)(p) + ARENA_SIZE_MASK) & ~ARENA_SIZE_MASK)) 43 #define ARENA_ALIGN_DOWN(p) ((char *)((uintptr_t)(p) & ~ARENA_SIZE_MASK)) 44 45 /* 46 * This structure should be no more than twice the size of the 47 * previous structure. 48 */ 49 struct free_arena_header { 50 struct arena_header a; 51 struct free_arena_header *next_free, *prev_free; 52 }; 53 54 extern struct free_arena_header __malloc_head; 55
