| 1 | /* |
| 2 | (c) FSF 2002. |
| 3 | */ |
| 4 | |
| 5 | |
| 6 | #ifndef PRIVATE_GC |
| 7 | #define PRIVATE_GC |
| 8 | |
| 9 | #include "_scm.h" |
| 10 | |
| 11 | /* {heap tuning parameters} |
| 12 | * |
| 13 | * These are parameters for controlling memory allocation. The heap |
| 14 | * is the area out of which scm_cons, and object headers are allocated. |
| 15 | * |
| 16 | * Each heap cell is 8 bytes on a 32 bit machine and 16 bytes on a |
| 17 | * 64 bit machine. The units of the _SIZE parameters are bytes. |
| 18 | * Cons pairs and object headers occupy one heap cell. |
| 19 | * |
| 20 | * SCM_INIT_HEAP_SIZE is the initial size of heap. If this much heap is |
| 21 | * allocated initially the heap will grow by half its current size |
| 22 | * each subsequent time more heap is needed. |
| 23 | * |
| 24 | * If SCM_INIT_HEAP_SIZE heap cannot be allocated initially, SCM_HEAP_SEG_SIZE |
| 25 | * will be used, and the heap will grow by SCM_HEAP_SEG_SIZE when more |
| 26 | * heap is needed. SCM_HEAP_SEG_SIZE must fit into type size_t. This code |
| 27 | * is in scm_init_storage() and alloc_some_heap() in sys.c |
| 28 | * |
| 29 | * If SCM_INIT_HEAP_SIZE can be allocated initially, the heap will grow by |
| 30 | * SCM_EXPHEAP(scm_heap_size) when more heap is needed. |
| 31 | * |
| 32 | * SCM_MIN_HEAP_SEG_SIZE is minimum size of heap to accept when more heap |
| 33 | * is needed. |
| 34 | */ |
| 35 | |
| 36 | |
| 37 | /* |
| 38 | * Heap size 45000 and 40% min yield gives quick startup and no extra |
| 39 | * heap allocation. Having higher values on min yield may lead to |
| 40 | * large heaps, especially if code behaviour is varying its |
| 41 | * maximum consumption between different freelists. |
| 42 | */ |
| 43 | |
| 44 | /* |
| 45 | These values used to be global C variables. However, they're also |
| 46 | available through the environment, and having a double interface is |
| 47 | confusing. Now they're #defines --hwn. |
| 48 | */ |
| 49 | |
| 50 | #define SCM_DEFAULT_INIT_HEAP_SIZE_1 256*1024 |
| 51 | #define SCM_DEFAULT_MIN_YIELD_1 40 |
| 52 | #define SCM_DEFAULT_INIT_HEAP_SIZE_2 32*1024 |
| 53 | |
| 54 | /* The following value may seem large, but note that if we get to GC at |
| 55 | * all, this means that we have a numerically intensive application |
| 56 | */ |
| 57 | #define SCM_DEFAULT_MIN_YIELD_2 40 |
| 58 | |
| 59 | #define SCM_DEFAULT_MAX_SEGMENT_SIZE (20*1024*1024L) |
| 60 | |
| 61 | |
| 62 | |
| 63 | #define SCM_MIN_HEAP_SEG_SIZE (8 * SCM_GC_SIZEOF_CARD) |
| 64 | #define SCM_HEAP_SEG_SIZE (16384L * sizeof (scm_t_cell)) |
| 65 | |
| 66 | |
| 67 | #define SCM_DOUBLECELL_ALIGNED_P(x) (((2 * sizeof (scm_t_cell) - 1) & SCM_UNPACK (x)) == 0) |
| 68 | |
| 69 | |
| 70 | #define SCM_GC_CARD_BVEC_SIZE_IN_LONGS \ |
| 71 | ((SCM_GC_CARD_N_CELLS + SCM_C_BVEC_LONG_BITS - 1) / SCM_C_BVEC_LONG_BITS) |
| 72 | #define SCM_GC_IN_CARD_HEADERP(x) \ |
| 73 | (scm_t_cell *) (x) < SCM_GC_CELL_CARD (x) + SCM_GC_CARD_N_HEADER_CELLS |
| 74 | |
| 75 | |
| 76 | int scm_getenv_int (const char *var, int def); |
| 77 | |
| 78 | |
| 79 | typedef enum { return_on_error, abort_on_error } policy_on_error; |
| 80 | |
| 81 | /* gc-freelist*/ |
| 82 | |
| 83 | /* |
| 84 | FREELIST: |
| 85 | |
| 86 | A struct holding GC statistics on a particular type of cells. |
| 87 | */ |
| 88 | typedef struct scm_t_cell_type_statistics { |
| 89 | |
| 90 | /* |
| 91 | heap segment where the last cell was allocated |
| 92 | */ |
| 93 | int heap_segment_idx; |
| 94 | |
| 95 | /* minimum yield on this list in order not to grow the heap |
| 96 | */ |
| 97 | long min_yield; |
| 98 | |
| 99 | /* defines min_yield as percent of total heap size |
| 100 | */ |
| 101 | int min_yield_fraction; |
| 102 | |
| 103 | /* number of cells per object on this list */ |
| 104 | int span; |
| 105 | |
| 106 | /* number of collected cells during last GC */ |
| 107 | unsigned long collected; |
| 108 | |
| 109 | /* number of collected cells during penultimate GC */ |
| 110 | unsigned long collected_1; |
| 111 | |
| 112 | /* total number of cells in heap segments |
| 113 | * belonging to this list. |
| 114 | */ |
| 115 | unsigned long heap_size; |
| 116 | |
| 117 | |
| 118 | } scm_t_cell_type_statistics; |
| 119 | |
| 120 | |
| 121 | extern scm_t_cell_type_statistics scm_i_master_freelist; |
| 122 | extern scm_t_cell_type_statistics scm_i_master_freelist2; |
| 123 | extern unsigned long scm_gc_cells_collected_1; |
| 124 | |
| 125 | void scm_i_adjust_min_yield (scm_t_cell_type_statistics *freelist); |
| 126 | void scm_i_gc_sweep_freelist_reset (scm_t_cell_type_statistics *freelist); |
| 127 | int scm_i_gc_grow_heap_p (scm_t_cell_type_statistics * freelist); |
| 128 | |
| 129 | |
| 130 | #define SCM_HEAP_SIZE \ |
| 131 | (scm_i_master_freelist.heap_size + scm_i_master_freelist2.heap_size) |
| 132 | |
| 133 | |
| 134 | #define SCM_MAX(A, B) ((A) > (B) ? (A) : (B)) |
| 135 | #define SCM_MIN(A, B) ((A) < (B) ? (A) : (B)) |
| 136 | |
| 137 | #define CELL_P(x) (SCM_ITAG3 (x) == scm_tc3_cons) |
| 138 | |
| 139 | /* |
| 140 | gc-mark |
| 141 | */ |
| 142 | |
| 143 | |
| 144 | void scm_mark_all (void); |
| 145 | |
| 146 | |
| 147 | |
| 148 | /* |
| 149 | gc-segment: |
| 150 | */ |
| 151 | |
| 152 | |
| 153 | |
| 154 | |
| 155 | /* |
| 156 | |
| 157 | Cells are stored in a heap-segment: it is a contiguous chunk of |
| 158 | memory, that associated with one freelist. |
| 159 | */ |
| 160 | |
| 161 | typedef struct scm_t_heap_segment |
| 162 | { |
| 163 | /* |
| 164 | {lower, upper} bounds of the segment |
| 165 | |
| 166 | The upper bound is also the start of the mark space. |
| 167 | */ |
| 168 | scm_t_cell *bounds[2]; |
| 169 | |
| 170 | /* |
| 171 | If we ever decide to give it back, we could do it with this ptr. |
| 172 | |
| 173 | Note that giving back memory is not very useful; as long we don't |
| 174 | touch a chunk of memory, the virtual memory system will keep it |
| 175 | swapped out. We could simply forget about a block. |
| 176 | |
| 177 | (not that we do that, but anyway.) |
| 178 | */ |
| 179 | |
| 180 | void* malloced; |
| 181 | |
| 182 | scm_t_cell * next_free_card; |
| 183 | |
| 184 | /* address of the head-of-freelist pointer for this segment's cells. |
| 185 | All segments usually point to the same one, scm_i_freelist. */ |
| 186 | scm_t_cell_type_statistics *freelist; |
| 187 | |
| 188 | /* number of cells per object in this segment */ |
| 189 | int span; |
| 190 | |
| 191 | |
| 192 | /* |
| 193 | Is this the first time that the cells are accessed? |
| 194 | */ |
| 195 | int first_time; |
| 196 | |
| 197 | } scm_t_heap_segment; |
| 198 | |
| 199 | |
| 200 | |
| 201 | /* |
| 202 | |
| 203 | A table of segment records is kept that records the upper and |
| 204 | lower extents of the segment; this is used during the conservative |
| 205 | phase of gc to identify probably gc roots (because they point |
| 206 | into valid segments at reasonable offsets). |
| 207 | |
| 208 | */ |
| 209 | extern scm_t_heap_segment ** scm_i_heap_segment_table; |
| 210 | extern size_t scm_i_heap_segment_table_size; |
| 211 | |
| 212 | |
| 213 | int scm_i_init_card_freelist (scm_t_cell * card, SCM *free_list,scm_t_heap_segment*); |
| 214 | int scm_i_sweep_card (scm_t_cell * card, SCM *free_list, scm_t_heap_segment*); |
| 215 | int scm_i_initialize_heap_segment_data (scm_t_heap_segment * segment, size_t requested); |
| 216 | int scm_i_segment_card_count (scm_t_heap_segment * seg); |
| 217 | int scm_i_segment_cell_count (scm_t_heap_segment * seg); |
| 218 | |
| 219 | void scm_i_clear_segment_mark_space (scm_t_heap_segment *seg); |
| 220 | scm_t_heap_segment * scm_i_make_empty_heap_segment (scm_t_cell_type_statistics*); |
| 221 | SCM scm_i_sweep_some_cards (scm_t_heap_segment *seg); |
| 222 | void scm_i_sweep_segment (scm_t_heap_segment * seg); |
| 223 | |
| 224 | |
| 225 | int scm_i_insert_segment (scm_t_heap_segment * seg); |
| 226 | long int scm_i_find_heap_segment_containing_object (SCM obj); |
| 227 | int scm_i_get_new_heap_segment (scm_t_cell_type_statistics *, policy_on_error); |
| 228 | void scm_i_clear_mark_space (void); |
| 229 | void scm_i_sweep_segments (void); |
| 230 | SCM scm_i_sweep_some_segments (scm_t_cell_type_statistics * fl); |
| 231 | void scm_i_reset_segments (void); |
| 232 | void scm_i_sweep_all_segments (char const *reason); |
| 233 | void scm_i_make_initial_segment (int init_heap_size, scm_t_cell_type_statistics *freelist); |
| 234 | |
| 235 | extern long int scm_i_deprecated_memory_return; |
| 236 | |
| 237 | |
| 238 | /* |
| 239 | global init funcs. |
| 240 | */ |
| 241 | void scm_gc_init_malloc (void); |
| 242 | void scm_gc_init_freelist (void); |
| 243 | void scm_gc_init_segments (void); |
| 244 | void scm_gc_init_mark (void); |
| 245 | |
| 246 | |
| 247 | #endif |