[bpt/guile.git] / libguile / private-gc.h

/*
 * private-gc.h - private declarations for garbage collection.
 * 
 * Copyright (C) 2002, 03, 04, 05, 06, 07 Free Software Foundation, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef PRIVATE_GC
#define PRIVATE_GC

#include  "_scm.h"

/* {heap tuning parameters}
 *
 * These are parameters for controlling memory allocation.  The heap
 * is the area out of which scm_cons, and object headers are allocated.
 *
 * Each heap cell is 8 bytes on a 32 bit machine and 16 bytes on a
 * 64 bit machine.  The units of the _SIZE parameters are bytes.
 * Cons pairs and object headers occupy one heap cell.
 *
 * SCM_INIT_HEAP_SIZE is the initial size of heap.  If this much heap is
 * allocated initially the heap will grow by half its current size
 * each subsequent time more heap is needed.
 *
 * If SCM_INIT_HEAP_SIZE heap cannot be allocated initially, SCM_HEAP_SEG_SIZE
 * will be used, and the heap will grow by SCM_HEAP_SEG_SIZE when more
 * heap is needed.  SCM_HEAP_SEG_SIZE must fit into type size_t.  This code
 * is in scm_init_storage() and alloc_some_heap() in sys.c
 *
 * If SCM_INIT_HEAP_SIZE can be allocated initially, the heap will grow by
 * SCM_EXPHEAP(scm_heap_size) when more heap is needed.
 *
 * SCM_MIN_HEAP_SEG_SIZE is minimum size of heap to accept when more heap
 * is needed.
 */


/*
 * Heap size 45000 and 40% min yield gives quick startup and no extra
 * heap allocation.  Having higher values on min yield may lead to
 * large heaps, especially if code behaviour is varying its
 * maximum consumption between different freelists.
 */

/*
  These values used to be global C variables. However, they're also
  available through the environment, and having a double interface is
  confusing. Now they're #defines --hwn.
 */

#define SCM_DEFAULT_INIT_HEAP_SIZE_1  256*1024
#define SCM_DEFAULT_MIN_YIELD_1 40
#define SCM_DEFAULT_INIT_HEAP_SIZE_2 32*1024

/* The following value may seem large, but note that if we get to GC at
 * all, this means that we have a numerically intensive application
 */
#define SCM_DEFAULT_MIN_YIELD_2 40

#define SCM_DEFAULT_MAX_SEGMENT_SIZE  (20*1024*1024L)


#define SCM_MIN_HEAP_SEG_SIZE (8 * SCM_GC_SIZEOF_CARD)
#define SCM_HEAP_SEG_SIZE (16384L * sizeof (scm_t_cell))


#define SCM_DOUBLECELL_ALIGNED_P(x)  (((2 * sizeof (scm_t_cell) - 1) & SCM_UNPACK (x)) == 0)


#define SCM_GC_CARD_BVEC_SIZE_IN_LONGS \
    ((SCM_GC_CARD_N_CELLS + SCM_C_BVEC_LONG_BITS - 1) / SCM_C_BVEC_LONG_BITS)
#define SCM_GC_IN_CARD_HEADERP(x) \
  (scm_t_cell *) (x) <  SCM_GC_CELL_CARD (x) + SCM_GC_CARD_N_HEADER_CELLS


int scm_getenv_int (const char *var, int def);


typedef enum { return_on_error, abort_on_error } policy_on_error;

/* gc-freelist*/

/*
  FREELIST:

  A struct holding GC statistics on a particular type of cells.
*/
typedef struct scm_t_cell_type_statistics {

  /*
    heap segment where the last cell was allocated 
  */
  int heap_segment_idx;

  /* minimum yield on this list in order not to grow the heap
   */
  long min_yield;

  /* defines min_yield as percent of total heap size
   */
  int min_yield_fraction;
  
  /* number of cells per object on this list */
  int span;

  /* number of collected cells during last GC */
  unsigned long collected;

  /* number of collected cells during penultimate GC */
  unsigned long collected_1;

  /* total number of cells in heap segments
   * belonging to this list.
   */
  unsigned long heap_size;

  
} scm_t_cell_type_statistics;


/* Sweep statistics.  */
typedef struct scm_sweep_statistics
{
  /* Number of cells "swept", i.e., visited during the sweep operation.  */
  unsigned swept;

  /* Number of cells collected during the sweep operation.  This number must
     alsways be lower than or equal to SWEPT.  */
  unsigned collected;
} scm_t_sweep_statistics;

#define scm_i_sweep_statistics_init(_stats)	\
  do						\
   {						\
     (_stats)->swept = (_stats)->collected = 0;	\
   }						\
  while (0)

#define scm_i_sweep_statistics_sum(_sum, _addition)	\
  do							\
   {							\
     (_sum)->swept += (_addition).swept;		\
     (_sum)->collected += (_addition).collected;	\
   }							\
  while (0)

\f
extern scm_t_cell_type_statistics scm_i_master_freelist;
extern scm_t_cell_type_statistics scm_i_master_freelist2;

void scm_i_adjust_min_yield (scm_t_cell_type_statistics *freelist,
			     scm_t_sweep_statistics sweep_stats,
			     scm_t_sweep_statistics sweep_stats_1);
void scm_i_gc_sweep_freelist_reset (scm_t_cell_type_statistics *freelist);
int scm_i_gc_grow_heap_p (scm_t_cell_type_statistics * freelist);


#define SCM_HEAP_SIZE \
  (scm_i_master_freelist.heap_size + scm_i_master_freelist2.heap_size)


#define SCM_MAX(A, B) ((A) > (B) ? (A) : (B))
#define SCM_MIN(A, B) ((A) < (B) ? (A) : (B))

/* CELL_P checks a random word whether it has the right form for a
   pointer to a cell.  Use scm_i_find_heap_segment_containing_object
   to find out whether it actually points to a real cell.

   The right form for a cell pointer is this: the low three bits must
   be scm_tc3_cons, and when the scm_tc3_cons tag is stripped, the
   resulting pointer must be correctly aligned.
   scm_i_initialize_heap_segment_data guarantees that the test below
   works.
*/
#define CELL_P(x)  ((SCM_UNPACK(x) & (sizeof(scm_t_cell)-1)) == scm_tc3_cons)

/*
  gc-mark
 */


void scm_mark_all (void);


/*
gc-segment:
*/


/*

 Cells are stored in a heap-segment: it is a contiguous chunk of
 memory, that associated with one freelist. 
*/

typedef struct scm_t_heap_segment
{
  /*
    {lower, upper} bounds of the segment

    The upper bound is also the start of the mark space.
  */
  scm_t_cell *bounds[2];

  /*
    If we ever decide to give it back, we could do it with this ptr.

    Note that giving back memory is not very useful; as long we don't
    touch a chunk of memory, the virtual memory system will keep it
    swapped out. We could simply forget about a block.

    (not that we do that, but anyway.) 
   */

  void* malloced;

  scm_t_cell * next_free_card;
  
  /* address of the head-of-freelist pointer for this segment's cells.
     All segments usually point to the same one, scm_i_freelist.  */
  scm_t_cell_type_statistics *freelist;
  
  /* number of cells per object in this segment */
  int span;


  /*
    Is this the first time that the cells are accessed? 
   */
  int first_time;
  
} scm_t_heap_segment;


/*

  A table of segment records is kept that records the upper and
  lower extents of the segment;  this is used during the conservative
  phase of gc to identify probably gc roots (because they point
  into valid segments at reasonable offsets).

*/
extern scm_t_heap_segment ** scm_i_heap_segment_table;
extern size_t scm_i_heap_segment_table_size;


int scm_i_init_card_freelist (scm_t_cell * card, SCM *free_list,scm_t_heap_segment*);
int scm_i_sweep_card (scm_t_cell * card, SCM *free_list, scm_t_heap_segment*);
void scm_i_card_statistics (scm_t_cell *p, SCM hashtab, scm_t_heap_segment *seg);
char const *scm_i_tag_name (scm_t_bits tag); /* MOVEME */

int scm_i_initialize_heap_segment_data (scm_t_heap_segment * segment, size_t requested);
int scm_i_segment_card_count (scm_t_heap_segment * seg);
int scm_i_segment_cell_count (scm_t_heap_segment * seg);

void scm_i_clear_segment_mark_space (scm_t_heap_segment *seg);
scm_t_heap_segment * scm_i_make_empty_heap_segment (scm_t_cell_type_statistics*);
SCM scm_i_sweep_some_cards (scm_t_heap_segment *seg,
			    scm_t_sweep_statistics *sweep_stats);
void scm_i_sweep_segment (scm_t_heap_segment *seg,
			  scm_t_sweep_statistics *sweep_stats);

void scm_i_heap_segment_statistics (scm_t_heap_segment *seg, SCM tab);

     
int scm_i_insert_segment (scm_t_heap_segment * seg);
long int scm_i_find_heap_segment_containing_object (SCM obj);
int scm_i_get_new_heap_segment (scm_t_cell_type_statistics *,
				scm_t_sweep_statistics,
				policy_on_error);
void scm_i_clear_mark_space (void);
void scm_i_sweep_segments (void);
SCM scm_i_sweep_some_segments (scm_t_cell_type_statistics *fl,
			       scm_t_sweep_statistics *sweep_stats);
void scm_i_reset_segments (void);
void scm_i_sweep_all_segments (char const *reason,
			       scm_t_sweep_statistics *sweep_stats);
SCM scm_i_all_segments_statistics (SCM hashtab);
void scm_i_make_initial_segment (int init_heap_size, scm_t_cell_type_statistics *freelist);

extern long int scm_i_deprecated_memory_return;


/*
  global init funcs.
 */
void scm_gc_init_malloc (void);
void scm_gc_init_freelist (void);
void scm_gc_init_segments (void);
void scm_gc_init_mark (void);


#endif
Commit	Line	Data
c7743d02	1	/*
cb90e2cb HWN	2	* private-gc.h - private declarations for garbage collection.
	3	*
	4	* Copyright (C) 2002, 03, 04, 05, 06, 07 Free Software Foundation, Inc.
	5	*
	6	* This library is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU Lesser General Public
	8	* License as published by the Free Software Foundation; either
	9	* version 2.1 of the License, or (at your option) any later version.
	10	*
	11	* This library is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* Lesser General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Lesser General Public
	17	* License along with this library; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
c7743d02 HWN	20
	21	#ifndef PRIVATE_GC
	22	#define PRIVATE_GC
	23
	24	#include "_scm.h"
	25
	26	/* {heap tuning parameters}
	27	*
	28	* These are parameters for controlling memory allocation. The heap
	29	* is the area out of which scm_cons, and object headers are allocated.
	30	*
	31	* Each heap cell is 8 bytes on a 32 bit machine and 16 bytes on a
	32	* 64 bit machine. The units of the _SIZE parameters are bytes.
	33	* Cons pairs and object headers occupy one heap cell.
	34	*
	35	* SCM_INIT_HEAP_SIZE is the initial size of heap. If this much heap is
	36	* allocated initially the heap will grow by half its current size
	37	* each subsequent time more heap is needed.
	38	*
	39	* If SCM_INIT_HEAP_SIZE heap cannot be allocated initially, SCM_HEAP_SEG_SIZE
	40	* will be used, and the heap will grow by SCM_HEAP_SEG_SIZE when more
	41	* heap is needed. SCM_HEAP_SEG_SIZE must fit into type size_t. This code
	42	* is in scm_init_storage() and alloc_some_heap() in sys.c
	43	*
	44	* If SCM_INIT_HEAP_SIZE can be allocated initially, the heap will grow by
	45	* SCM_EXPHEAP(scm_heap_size) when more heap is needed.
	46	*
	47	* SCM_MIN_HEAP_SEG_SIZE is minimum size of heap to accept when more heap
	48	* is needed.
	49	*/
	50
	51
	52	/*
	53	* Heap size 45000 and 40% min yield gives quick startup and no extra
	54	* heap allocation. Having higher values on min yield may lead to
	55	* large heaps, especially if code behaviour is varying its
	56	* maximum consumption between different freelists.
	57	*/
	58
	59	/*
	60	These values used to be global C variables. However, they're also
	61	available through the environment, and having a double interface is
	62	confusing. Now they're #defines --hwn.
	63	*/
	64
	65	#define SCM_DEFAULT_INIT_HEAP_SIZE_1 256*1024
	66	#define SCM_DEFAULT_MIN_YIELD_1 40
	67	#define SCM_DEFAULT_INIT_HEAP_SIZE_2 32*1024
	68
	69	/* The following value may seem large, but note that if we get to GC at
	70	* all, this means that we have a numerically intensive application
	71	*/
	72	#define SCM_DEFAULT_MIN_YIELD_2 40
322a2bf7 MV	73
322a2bf7 MV	74	#define SCM_DEFAULT_MAX_SEGMENT_SIZE (2010241024L)
c7743d02 HWN	75
	76
	77
	78	#define SCM_MIN_HEAP_SEG_SIZE (8 * SCM_GC_SIZEOF_CARD)
	79	#define SCM_HEAP_SEG_SIZE (16384L * sizeof (scm_t_cell))
	80
	81
1383773b	82	#define SCM_DOUBLECELL_ALIGNED_P(x) (((2 * sizeof (scm_t_cell) - 1) & SCM_UNPACK (x)) == 0)
c7743d02 HWN	83
c7743d02 HWN	84
1383773b HWN	85	#define SCM_GC_CARD_BVEC_SIZE_IN_LONGS \
	86	((SCM_GC_CARD_N_CELLS + SCM_C_BVEC_LONG_BITS - 1) / SCM_C_BVEC_LONG_BITS)
	87	#define SCM_GC_IN_CARD_HEADERP(x) \
	88	(scm_t_cell *) (x) < SCM_GC_CELL_CARD (x) + SCM_GC_CARD_N_HEADER_CELLS
c7743d02 HWN	89
	90
	91	int scm_getenv_int (const char *var, int def);
	92
	93
	94	typedef enum { return_on_error, abort_on_error } policy_on_error;
	95
	96	/* gc-freelist*/
	97
	98	/*
	99	FREELIST:
	100
	101	A struct holding GC statistics on a particular type of cells.
	102	*/
	103	typedef struct scm_t_cell_type_statistics {
	104
	105	/*
	106	heap segment where the last cell was allocated
	107	*/
	108	int heap_segment_idx;
	109
	110	/* minimum yield on this list in order not to grow the heap
	111	*/
	112	long min_yield;
	113
	114	/* defines min_yield as percent of total heap size
	115	*/
	116	int min_yield_fraction;
	117
	118	/* number of cells per object on this list */
	119	int span;
	120
	121	/* number of collected cells during last GC */
	122	unsigned long collected;
	123
	124	/* number of collected cells during penultimate GC */
	125	unsigned long collected_1;
	126
	127	/* total number of cells in heap segments
	128	* belonging to this list.
	129	*/
	130	unsigned long heap_size;
	131
c2cbcc57	132
c7743d02 HWN	133	} scm_t_cell_type_statistics;
	134
	135
4c7016dc HWN	136	/* Sweep statistics. */
	137	typedef struct scm_sweep_statistics
	138	{
	139	/* Number of cells "swept", i.e., visited during the sweep operation. */
	140	unsigned swept;
	141
	142	/* Number of cells collected during the sweep operation. This number must
	143	alsways be lower than or equal to SWEPT. */
	144	unsigned collected;
	145	} scm_t_sweep_statistics;
	146
	147	#define scm_i_sweep_statistics_init(_stats) \
	148	do \
	149	{ \
	150	(_stats)->swept = (_stats)->collected = 0; \
	151	} \
	152	while (0)
	153
	154	#define scm_i_sweep_statistics_sum(_sum, _addition) \
	155	do \
	156	{ \
	157	(_sum)->swept += (_addition).swept; \
	158	(_sum)->collected += (_addition).collected; \
	159	} \
	160	while (0)
	161
4c7016dc	162	\f
c7743d02 HWN	163	extern scm_t_cell_type_statistics scm_i_master_freelist;
c7743d02 HWN	164	extern scm_t_cell_type_statistics scm_i_master_freelist2;
c7743d02	165
4c7016dc	166	void scm_i_adjust_min_yield (scm_t_cell_type_statistics *freelist,
d9f71a07 LC	167	scm_t_sweep_statistics sweep_stats,
d9f71a07 LC	168	scm_t_sweep_statistics sweep_stats_1);
c7743d02 HWN	169	void scm_i_gc_sweep_freelist_reset (scm_t_cell_type_statistics *freelist);
c7743d02 HWN	170	int scm_i_gc_grow_heap_p (scm_t_cell_type_statistics * freelist);
dac04e9f HWN	171
dac04e9f HWN	172
c7743d02 HWN	173	#define SCM_HEAP_SIZE \
	174	(scm_i_master_freelist.heap_size + scm_i_master_freelist2.heap_size)
	175
	176
	177	#define SCM_MAX(A, B) ((A) > (B) ? (A) : (B))
	178	#define SCM_MIN(A, B) ((A) < (B) ? (A) : (B))
	179
d3774e2c MV	180	/* CELL_P checks a random word whether it has the right form for a
	181	pointer to a cell. Use scm_i_find_heap_segment_containing_object
	182	to find out whether it actually points to a real cell.
	183
	184	The right form for a cell pointer is this: the low three bits must
	185	be scm_tc3_cons, and when the scm_tc3_cons tag is stripped, the
	186	resulting pointer must be correctly aligned.
	187	scm_i_initialize_heap_segment_data guarantees that the test below
	188	works.
	189	*/
	190	#define CELL_P(x) ((SCM_UNPACK(x) & (sizeof(scm_t_cell)-1)) == scm_tc3_cons)
c7743d02 HWN	191
	192	/*
	193	gc-mark
	194	*/
	195
	196
	197	void scm_mark_all (void);
	198
	199
	200
	201	/*
	202	gc-segment:
	203	*/
	204
	205
	206
	207
	208	/*
	209
	210	Cells are stored in a heap-segment: it is a contiguous chunk of
	211	memory, that associated with one freelist.
	212	*/
	213
	214	typedef struct scm_t_heap_segment
	215	{
	216	/*
	217	{lower, upper} bounds of the segment
	218
	219	The upper bound is also the start of the mark space.
	220	*/
	221	scm_t_cell *bounds[2];
	222
	223	/*
	224	If we ever decide to give it back, we could do it with this ptr.
	225
	226	Note that giving back memory is not very useful; as long we don't
	227	touch a chunk of memory, the virtual memory system will keep it
	228	swapped out. We could simply forget about a block.
	229
	230	(not that we do that, but anyway.)
	231	*/
	232
	233	void* malloced;
	234
	235	scm_t_cell * next_free_card;
	236
	237	/* address of the head-of-freelist pointer for this segment's cells.
	238	All segments usually point to the same one, scm_i_freelist. */
	239	scm_t_cell_type_statistics *freelist;
	240
	241	/* number of cells per object in this segment */
	242	int span;
	243
	244
	245	/*
	246	Is this the first time that the cells are accessed?
	247	*/
	248	int first_time;
	249
	250	} scm_t_heap_segment;
	251
	252
	253
	254	/*
255
256	A table of segment records is kept that records the upper and
257	lower extents of the segment; this is used during the conservative
258	phase of gc to identify probably gc roots (because they point
259	into valid segments at reasonable offsets).
260
261	*/
262	extern scm_t_heap_segment ** scm_i_heap_segment_table;
263	extern size_t scm_i_heap_segment_table_size;
264
265
1383773b HWN	266	int scm_i_init_card_freelist (scm_t_cell * card, SCM free_list,scm_t_heap_segment);
1383773b HWN	267	int scm_i_sweep_card (scm_t_cell * card, SCM free_list, scm_t_heap_segment);
1367aa5e HWN	268	void scm_i_card_statistics (scm_t_cell p, SCM hashtab, scm_t_heap_segment seg);
	269	char const scm_i_tag_name (scm_t_bits tag); / MOVEME */
	270
c7743d02 HWN	271	int scm_i_initialize_heap_segment_data (scm_t_heap_segment * segment, size_t requested);
	272	int scm_i_segment_card_count (scm_t_heap_segment * seg);
	273	int scm_i_segment_cell_count (scm_t_heap_segment * seg);
	274
	275	void scm_i_clear_segment_mark_space (scm_t_heap_segment *seg);
	276	scm_t_heap_segment * scm_i_make_empty_heap_segment (scm_t_cell_type_statistics*);
4c7016dc HWN	277	SCM scm_i_sweep_some_cards (scm_t_heap_segment *seg,
	278	scm_t_sweep_statistics *sweep_stats);
	279	void scm_i_sweep_segment (scm_t_heap_segment *seg,
	280	scm_t_sweep_statistics *sweep_stats);
c7743d02	281
1367aa5e HWN	282	void scm_i_heap_segment_statistics (scm_t_heap_segment *seg, SCM tab);
1367aa5e HWN	283
c7743d02 HWN	284
	285	int scm_i_insert_segment (scm_t_heap_segment * seg);
	286	long int scm_i_find_heap_segment_containing_object (SCM obj);
d9f71a07 LC	287	int scm_i_get_new_heap_segment (scm_t_cell_type_statistics *,
	288	scm_t_sweep_statistics,
	289	policy_on_error);
c7743d02 HWN	290	void scm_i_clear_mark_space (void);
c7743d02 HWN	291	void scm_i_sweep_segments (void);
4c7016dc HWN	292	SCM scm_i_sweep_some_segments (scm_t_cell_type_statistics *fl,
4c7016dc HWN	293	scm_t_sweep_statistics *sweep_stats);
c7743d02	294	void scm_i_reset_segments (void);
4c7016dc HWN	295	void scm_i_sweep_all_segments (char const *reason,
4c7016dc HWN	296	scm_t_sweep_statistics *sweep_stats);
1367aa5e	297	SCM scm_i_all_segments_statistics (SCM hashtab);
dac04e9f	298	void scm_i_make_initial_segment (int init_heap_size, scm_t_cell_type_statistics *freelist);
c7743d02 HWN	299
	300	extern long int scm_i_deprecated_memory_return;
	301
	302
	303	/*
	304	global init funcs.
	305	*/
	306	void scm_gc_init_malloc (void);
	307	void scm_gc_init_freelist (void);
	308	void scm_gc_init_segments (void);
	309	void scm_gc_init_mark (void);
eab1b259 HWN	310
eab1b259 HWN	311
c7743d02	312	#endif