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 /* CELL_P checks a random word whether it has the right form for a 138 pointer to a cell. Use scm_i_find_heap_segment_containing_object 139 to find out whether it actually points to a real cell. 140 141 The right form for a cell pointer is this: the low three bits must 142 be scm_tc3_cons, and when the scm_tc3_cons tag is stripped, the 143 resulting pointer must be correctly aligned. 144 scm_i_initialize_heap_segment_data guarantees that the test below 145 works. 146 */ 147 #define CELL_P(x) ((SCM_UNPACK(x) & (sizeof(scm_t_cell)-1)) == scm_tc3_cons) 148 149 /* 150 gc-mark 151 */ 152 153 154 void scm_mark_all (void); 155 156 157 158 /* 159 gc-segment: 160 */ 161 162 163 164 165 /* 166 167 Cells are stored in a heap-segment: it is a contiguous chunk of 168 memory, that associated with one freelist. 169 */ 170 171 typedef struct scm_t_heap_segment 172 { 173 /* 174 {lower, upper} bounds of the segment 175 176 The upper bound is also the start of the mark space. 177 */ 178 scm_t_cell *bounds[2]; 179 180 /* 181 If we ever decide to give it back, we could do it with this ptr. 182 183 Note that giving back memory is not very useful; as long we don't 184 touch a chunk of memory, the virtual memory system will keep it 185 swapped out. We could simply forget about a block. 186 187 (not that we do that, but anyway.) 188 */ 189 190 void* malloced; 191 192 scm_t_cell * next_free_card; 193 194 /* address of the head-of-freelist pointer for this segment's cells. 195 All segments usually point to the same one, scm_i_freelist. */ 196 scm_t_cell_type_statistics *freelist; 197 198 /* number of cells per object in this segment */ 199 int span; 200 201 202 /* 203 Is this the first time that the cells are accessed? 204 */ 205 int first_time; 206 207 } scm_t_heap_segment; 208 209 210 211 /* 212 213 A table of segment records is kept that records the upper and 214 lower extents of the segment; this is used during the conservative 215 phase of gc to identify probably gc roots (because they point 216 into valid segments at reasonable offsets). 217 218 */ 219 extern scm_t_heap_segment ** scm_i_heap_segment_table; 220 extern size_t scm_i_heap_segment_table_size; 221 222 223 int scm_i_init_card_freelist (scm_t_cell * card, SCM *free_list,scm_t_heap_segment*); 224 int scm_i_sweep_card (scm_t_cell * card, SCM *free_list, scm_t_heap_segment*); 225 void scm_i_card_statistics (scm_t_cell *p, SCM hashtab, scm_t_heap_segment *seg); 226 char const *scm_i_tag_name (scm_t_bits tag); /* MOVEME */ 227 228 int scm_i_initialize_heap_segment_data (scm_t_heap_segment * segment, size_t requested); 229 int scm_i_segment_card_count (scm_t_heap_segment * seg); 230 int scm_i_segment_cell_count (scm_t_heap_segment * seg); 231 232 void scm_i_clear_segment_mark_space (scm_t_heap_segment *seg); 233 scm_t_heap_segment * scm_i_make_empty_heap_segment (scm_t_cell_type_statistics*); 234 SCM scm_i_sweep_some_cards (scm_t_heap_segment *seg); 235 void scm_i_sweep_segment (scm_t_heap_segment * seg); 236 237 void scm_i_heap_segment_statistics (scm_t_heap_segment *seg, SCM tab); 238 239 240 int scm_i_insert_segment (scm_t_heap_segment * seg); 241 long int scm_i_find_heap_segment_containing_object (SCM obj); 242 int scm_i_get_new_heap_segment (scm_t_cell_type_statistics *, policy_on_error); 243 void scm_i_clear_mark_space (void); 244 void scm_i_sweep_segments (void); 245 SCM scm_i_sweep_some_segments (scm_t_cell_type_statistics * fl); 246 void scm_i_reset_segments (void); 247 void scm_i_sweep_all_segments (char const *reason); 248 SCM scm_i_all_segments_statistics (SCM hashtab); 249 void scm_i_make_initial_segment (int init_heap_size, scm_t_cell_type_statistics *freelist); 250 251 extern long int scm_i_deprecated_memory_return; 252 253 254 /* 255 global init funcs. 256 */ 257 void scm_gc_init_malloc (void); 258 void scm_gc_init_freelist (void); 259 void scm_gc_init_segments (void); 260 void scm_gc_init_mark (void); 261 262 263 #endif 264