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296 lines
8.2 KiB
C
296 lines
8.2 KiB
C
/*
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(c) FSF 2002.
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*/
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#ifndef PRIVATE_GC
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#define PRIVATE_GC
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#include "_scm.h"
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/* {heap tuning parameters}
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*
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* These are parameters for controlling memory allocation. The heap
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* is the area out of which scm_cons, and object headers are allocated.
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*
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* Each heap cell is 8 bytes on a 32 bit machine and 16 bytes on a
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* 64 bit machine. The units of the _SIZE parameters are bytes.
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* Cons pairs and object headers occupy one heap cell.
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*
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* SCM_INIT_HEAP_SIZE is the initial size of heap. If this much heap is
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* allocated initially the heap will grow by half its current size
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* each subsequent time more heap is needed.
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*
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* If SCM_INIT_HEAP_SIZE heap cannot be allocated initially, SCM_HEAP_SEG_SIZE
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* will be used, and the heap will grow by SCM_HEAP_SEG_SIZE when more
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* heap is needed. SCM_HEAP_SEG_SIZE must fit into type size_t. This code
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* is in scm_init_storage() and alloc_some_heap() in sys.c
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*
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* If SCM_INIT_HEAP_SIZE can be allocated initially, the heap will grow by
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* SCM_EXPHEAP(scm_heap_size) when more heap is needed.
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*
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* SCM_MIN_HEAP_SEG_SIZE is minimum size of heap to accept when more heap
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* is needed.
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*/
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/*
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* Heap size 45000 and 40% min yield gives quick startup and no extra
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* heap allocation. Having higher values on min yield may lead to
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* large heaps, especially if code behaviour is varying its
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* maximum consumption between different freelists.
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*/
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/*
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These values used to be global C variables. However, they're also
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available through the environment, and having a double interface is
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confusing. Now they're #defines --hwn.
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*/
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#define SCM_DEFAULT_INIT_HEAP_SIZE_1 256*1024
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#define SCM_DEFAULT_MIN_YIELD_1 40
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#define SCM_DEFAULT_INIT_HEAP_SIZE_2 32*1024
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/* The following value may seem large, but note that if we get to GC at
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* all, this means that we have a numerically intensive application
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*/
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#define SCM_DEFAULT_MIN_YIELD_2 40
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#define SCM_DEFAULT_MAX_SEGMENT_SIZE (20*1024*1024L)
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#define SCM_MIN_HEAP_SEG_SIZE (8 * SCM_GC_SIZEOF_CARD)
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#define SCM_HEAP_SEG_SIZE (16384L * sizeof (scm_t_cell))
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#define SCM_DOUBLECELL_ALIGNED_P(x) (((2 * sizeof (scm_t_cell) - 1) & SCM_UNPACK (x)) == 0)
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#define SCM_GC_CARD_BVEC_SIZE_IN_LONGS \
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((SCM_GC_CARD_N_CELLS + SCM_C_BVEC_LONG_BITS - 1) / SCM_C_BVEC_LONG_BITS)
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#define SCM_GC_IN_CARD_HEADERP(x) \
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(scm_t_cell *) (x) < SCM_GC_CELL_CARD (x) + SCM_GC_CARD_N_HEADER_CELLS
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int scm_getenv_int (const char *var, int def);
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typedef enum { return_on_error, abort_on_error } policy_on_error;
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/* gc-freelist*/
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/*
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FREELIST:
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A struct holding GC statistics on a particular type of cells.
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*/
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typedef struct scm_t_cell_type_statistics {
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/*
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heap segment where the last cell was allocated
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*/
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int heap_segment_idx;
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/* minimum yield on this list in order not to grow the heap
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*/
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long min_yield;
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/* defines min_yield as percent of total heap size
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*/
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int min_yield_fraction;
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/* number of cells per object on this list */
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int span;
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/* number of collected cells during last GC */
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unsigned long collected;
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/* number of collected cells during penultimate GC */
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unsigned long collected_1;
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/* total number of cells in heap segments
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* belonging to this list.
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*/
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unsigned long heap_size;
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} scm_t_cell_type_statistics;
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/* Sweep statistics. */
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typedef struct scm_sweep_statistics
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{
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/* Number of cells "swept", i.e., visited during the sweep operation. */
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unsigned swept;
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/* Number of cells collected during the sweep operation. This number must
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alsways be lower than or equal to SWEPT. */
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unsigned collected;
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} scm_t_sweep_statistics;
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#define scm_i_sweep_statistics_init(_stats) \
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do \
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{ \
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(_stats)->swept = (_stats)->collected = 0; \
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} \
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while (0)
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#define scm_i_sweep_statistics_sum(_sum, _addition) \
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do \
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{ \
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(_sum)->swept += (_addition).swept; \
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(_sum)->collected += (_addition).collected; \
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} \
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while (0)
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extern scm_t_cell_type_statistics scm_i_master_freelist;
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extern scm_t_cell_type_statistics scm_i_master_freelist2;
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extern unsigned long scm_gc_cells_collected_1;
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void scm_i_adjust_min_yield (scm_t_cell_type_statistics *freelist,
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scm_t_sweep_statistics sweep_stats);
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void scm_i_gc_sweep_freelist_reset (scm_t_cell_type_statistics *freelist);
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int scm_i_gc_grow_heap_p (scm_t_cell_type_statistics * freelist);
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#define SCM_HEAP_SIZE \
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(scm_i_master_freelist.heap_size + scm_i_master_freelist2.heap_size)
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#define SCM_MAX(A, B) ((A) > (B) ? (A) : (B))
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#define SCM_MIN(A, B) ((A) < (B) ? (A) : (B))
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/* CELL_P checks a random word whether it has the right form for a
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pointer to a cell. Use scm_i_find_heap_segment_containing_object
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to find out whether it actually points to a real cell.
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The right form for a cell pointer is this: the low three bits must
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be scm_tc3_cons, and when the scm_tc3_cons tag is stripped, the
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resulting pointer must be correctly aligned.
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scm_i_initialize_heap_segment_data guarantees that the test below
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works.
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*/
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#define CELL_P(x) ((SCM_UNPACK(x) & (sizeof(scm_t_cell)-1)) == scm_tc3_cons)
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/*
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gc-mark
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*/
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void scm_mark_all (void);
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/*
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gc-segment:
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*/
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/*
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Cells are stored in a heap-segment: it is a contiguous chunk of
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memory, that associated with one freelist.
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*/
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typedef struct scm_t_heap_segment
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{
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/*
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{lower, upper} bounds of the segment
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The upper bound is also the start of the mark space.
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*/
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scm_t_cell *bounds[2];
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/*
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If we ever decide to give it back, we could do it with this ptr.
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Note that giving back memory is not very useful; as long we don't
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touch a chunk of memory, the virtual memory system will keep it
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swapped out. We could simply forget about a block.
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(not that we do that, but anyway.)
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*/
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void* malloced;
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scm_t_cell * next_free_card;
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/* address of the head-of-freelist pointer for this segment's cells.
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All segments usually point to the same one, scm_i_freelist. */
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scm_t_cell_type_statistics *freelist;
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/* number of cells per object in this segment */
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int span;
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/*
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Is this the first time that the cells are accessed?
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*/
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int first_time;
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} scm_t_heap_segment;
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/*
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A table of segment records is kept that records the upper and
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lower extents of the segment; this is used during the conservative
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phase of gc to identify probably gc roots (because they point
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into valid segments at reasonable offsets).
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*/
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extern scm_t_heap_segment ** scm_i_heap_segment_table;
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extern size_t scm_i_heap_segment_table_size;
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int scm_i_init_card_freelist (scm_t_cell * card, SCM *free_list,scm_t_heap_segment*);
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int scm_i_sweep_card (scm_t_cell * card, SCM *free_list, scm_t_heap_segment*);
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void scm_i_card_statistics (scm_t_cell *p, SCM hashtab, scm_t_heap_segment *seg);
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char const *scm_i_tag_name (scm_t_bits tag); /* MOVEME */
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int scm_i_initialize_heap_segment_data (scm_t_heap_segment * segment, size_t requested);
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int scm_i_segment_card_count (scm_t_heap_segment * seg);
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int scm_i_segment_cell_count (scm_t_heap_segment * seg);
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void scm_i_clear_segment_mark_space (scm_t_heap_segment *seg);
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scm_t_heap_segment * scm_i_make_empty_heap_segment (scm_t_cell_type_statistics*);
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SCM scm_i_sweep_some_cards (scm_t_heap_segment *seg,
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scm_t_sweep_statistics *sweep_stats);
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void scm_i_sweep_segment (scm_t_heap_segment *seg,
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scm_t_sweep_statistics *sweep_stats);
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void scm_i_heap_segment_statistics (scm_t_heap_segment *seg, SCM tab);
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int scm_i_insert_segment (scm_t_heap_segment * seg);
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long int scm_i_find_heap_segment_containing_object (SCM obj);
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int scm_i_get_new_heap_segment (scm_t_cell_type_statistics *, policy_on_error);
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void scm_i_clear_mark_space (void);
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void scm_i_sweep_segments (void);
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SCM scm_i_sweep_some_segments (scm_t_cell_type_statistics *fl,
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scm_t_sweep_statistics *sweep_stats);
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void scm_i_reset_segments (void);
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void scm_i_sweep_all_segments (char const *reason,
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scm_t_sweep_statistics *sweep_stats);
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SCM scm_i_all_segments_statistics (SCM hashtab);
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void scm_i_make_initial_segment (int init_heap_size, scm_t_cell_type_statistics *freelist);
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extern long int scm_i_deprecated_memory_return;
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/*
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global init funcs.
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*/
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void scm_gc_init_malloc (void);
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void scm_gc_init_freelist (void);
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void scm_gc_init_segments (void);
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void scm_gc_init_mark (void);
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#endif
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