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c7743d02 HWN |
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 | #define SCM_DEFAULT_MAX_SEGMENT_SIZE 2097000L /* a little less (adm) than 2 Mb */ | |
59 | ||
60 | ||
61 | ||
62 | #define SCM_MIN_HEAP_SEG_SIZE (8 * SCM_GC_SIZEOF_CARD) | |
63 | #define SCM_HEAP_SEG_SIZE (16384L * sizeof (scm_t_cell)) | |
64 | ||
65 | ||
66 | #define DOUBLECELL_ALIGNED_P(x) (((2 * sizeof (scm_t_cell) - 1) & SCM_UNPACK (x)) == 0) | |
67 | ||
68 | ||
69 | ||
70 | ||
71 | int scm_getenv_int (const char *var, int def); | |
72 | ||
73 | ||
74 | typedef enum { return_on_error, abort_on_error } policy_on_error; | |
75 | ||
76 | /* gc-freelist*/ | |
77 | ||
78 | /* | |
79 | FREELIST: | |
80 | ||
81 | A struct holding GC statistics on a particular type of cells. | |
82 | */ | |
83 | typedef struct scm_t_cell_type_statistics { | |
84 | ||
85 | /* | |
86 | heap segment where the last cell was allocated | |
87 | */ | |
88 | int heap_segment_idx; | |
89 | ||
90 | /* minimum yield on this list in order not to grow the heap | |
91 | */ | |
92 | long min_yield; | |
93 | ||
94 | /* defines min_yield as percent of total heap size | |
95 | */ | |
96 | int min_yield_fraction; | |
97 | ||
98 | /* number of cells per object on this list */ | |
99 | int span; | |
100 | ||
101 | /* number of collected cells during last GC */ | |
102 | unsigned long collected; | |
103 | ||
104 | /* number of collected cells during penultimate GC */ | |
105 | unsigned long collected_1; | |
106 | ||
107 | /* total number of cells in heap segments | |
108 | * belonging to this list. | |
109 | */ | |
110 | unsigned long heap_size; | |
111 | ||
112 | } scm_t_cell_type_statistics; | |
113 | ||
114 | ||
115 | extern scm_t_cell_type_statistics scm_i_master_freelist; | |
116 | extern scm_t_cell_type_statistics scm_i_master_freelist2; | |
117 | extern unsigned long scm_gc_cells_collected_1; | |
118 | ||
119 | void scm_i_adjust_min_yield (scm_t_cell_type_statistics *freelist); | |
120 | void scm_i_gc_sweep_freelist_reset (scm_t_cell_type_statistics *freelist); | |
121 | int scm_i_gc_grow_heap_p (scm_t_cell_type_statistics * freelist); | |
122 | ||
123 | #define SCM_HEAP_SIZE \ | |
124 | (scm_i_master_freelist.heap_size + scm_i_master_freelist2.heap_size) | |
125 | ||
126 | ||
127 | #define SCM_MAX(A, B) ((A) > (B) ? (A) : (B)) | |
128 | #define SCM_MIN(A, B) ((A) < (B) ? (A) : (B)) | |
129 | ||
130 | #define CELL_P(x) (SCM_ITAG3 (x) == scm_tc3_cons) | |
131 | ||
132 | /* | |
133 | gc-mark | |
134 | */ | |
135 | ||
136 | ||
137 | void scm_mark_all (void); | |
138 | ||
139 | ||
140 | ||
141 | /* | |
142 | gc-segment: | |
143 | */ | |
144 | ||
145 | ||
146 | ||
147 | ||
148 | /* | |
149 | ||
150 | Cells are stored in a heap-segment: it is a contiguous chunk of | |
151 | memory, that associated with one freelist. | |
152 | */ | |
153 | ||
154 | typedef struct scm_t_heap_segment | |
155 | { | |
156 | /* | |
157 | {lower, upper} bounds of the segment | |
158 | ||
159 | The upper bound is also the start of the mark space. | |
160 | */ | |
161 | scm_t_cell *bounds[2]; | |
162 | ||
163 | /* | |
164 | If we ever decide to give it back, we could do it with this ptr. | |
165 | ||
166 | Note that giving back memory is not very useful; as long we don't | |
167 | touch a chunk of memory, the virtual memory system will keep it | |
168 | swapped out. We could simply forget about a block. | |
169 | ||
170 | (not that we do that, but anyway.) | |
171 | */ | |
172 | ||
173 | void* malloced; | |
174 | ||
175 | scm_t_cell * next_free_card; | |
176 | ||
177 | /* address of the head-of-freelist pointer for this segment's cells. | |
178 | All segments usually point to the same one, scm_i_freelist. */ | |
179 | scm_t_cell_type_statistics *freelist; | |
180 | ||
181 | /* number of cells per object in this segment */ | |
182 | int span; | |
183 | ||
184 | ||
185 | /* | |
186 | Is this the first time that the cells are accessed? | |
187 | */ | |
188 | int first_time; | |
189 | ||
190 | } scm_t_heap_segment; | |
191 | ||
192 | ||
193 | ||
194 | /* | |
195 | ||
196 | A table of segment records is kept that records the upper and | |
197 | lower extents of the segment; this is used during the conservative | |
198 | phase of gc to identify probably gc roots (because they point | |
199 | into valid segments at reasonable offsets). | |
200 | ||
201 | */ | |
202 | extern scm_t_heap_segment ** scm_i_heap_segment_table; | |
203 | extern size_t scm_i_heap_segment_table_size; | |
204 | ||
205 | ||
206 | int scm_init_card_freelist (scm_t_cell * card, SCM *free_list,int); | |
207 | int scm_i_sweep_card (scm_t_cell * card, SCM *free_list,int); | |
208 | int scm_i_initialize_heap_segment_data (scm_t_heap_segment * segment, size_t requested); | |
209 | int scm_i_segment_card_count (scm_t_heap_segment * seg); | |
210 | int scm_i_segment_cell_count (scm_t_heap_segment * seg); | |
211 | ||
212 | void scm_i_clear_segment_mark_space (scm_t_heap_segment *seg); | |
213 | scm_t_heap_segment * scm_i_make_empty_heap_segment (scm_t_cell_type_statistics*); | |
214 | SCM scm_i_sweep_some_cards (scm_t_heap_segment *seg); | |
215 | void scm_i_sweep_segment (scm_t_heap_segment * seg); | |
216 | ||
217 | ||
218 | int scm_i_insert_segment (scm_t_heap_segment * seg); | |
219 | long int scm_i_find_heap_segment_containing_object (SCM obj); | |
220 | int scm_i_get_new_heap_segment (scm_t_cell_type_statistics *, policy_on_error); | |
221 | void scm_i_clear_mark_space (void); | |
222 | void scm_i_sweep_segments (void); | |
223 | SCM scm_i_sweep_some_segments (scm_t_cell_type_statistics * fl); | |
224 | void scm_i_reset_segments (void); | |
225 | void scm_i_sweep_all_segments (char const *reason); | |
226 | void scm_i_make_initial_segment (size_t init_heap_size, scm_t_cell_type_statistics *freelist); | |
227 | ||
228 | extern long int scm_i_deprecated_memory_return; | |
229 | ||
230 | ||
231 | /* | |
232 | global init funcs. | |
233 | */ | |
234 | void scm_gc_init_malloc (void); | |
235 | void scm_gc_init_freelist (void); | |
236 | void scm_gc_init_segments (void); | |
237 | void scm_gc_init_mark (void); | |
238 | ||
239 | #endif |