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gcc/boehm-gc/reclaim.c
Bryce McKinlay 54f28c21ee Import Boehm GC version 6.6. 
From-SVN: r110204
2006-01-25 03:03:14 +00:00

1062 lines
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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved.
* Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
* Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
#include <stdio.h>
#include "private/gc_priv.h"
signed_word GC_mem_found = 0;
/* Number of words of memory reclaimed */
#if defined(PARALLEL_MARK) || defined(THREAD_LOCAL_ALLOC)
word GC_fl_builder_count = 0;
/* Number of threads currently building free lists without */
/* holding GC lock. It is not safe to collect if this is */
/* nonzero. */
#endif /* PARALLEL_MARK */
/* We defer printing of leaked objects until we're done with the GC */
/* cycle, since the routine for printing objects needs to run outside */
/* the collector, e.g. without the allocation lock. */
#define MAX_LEAKED 40
ptr_t GC_leaked[MAX_LEAKED];
unsigned GC_n_leaked = 0;
GC_bool GC_have_errors = FALSE;
void GC_add_leaked(leaked)
ptr_t leaked;
{
if (GC_n_leaked < MAX_LEAKED) {
GC_have_errors = TRUE;
GC_leaked[GC_n_leaked++] = leaked;
/* Make sure it's not reclaimed this cycle */
GC_set_mark_bit(leaked);
}
}
static GC_bool printing_errors = FALSE;
/* Print all objects on the list after printing any smashed objs. */
/* Clear both lists. */
void GC_print_all_errors ()
{
unsigned i;
LOCK();
if (printing_errors) {
UNLOCK();
return;
}
printing_errors = TRUE;
UNLOCK();
if (GC_debugging_started) GC_print_all_smashed();
for (i = 0; i < GC_n_leaked; ++i) {
ptr_t p = GC_leaked[i];
if (HDR(p) -> hb_obj_kind == PTRFREE) {
GC_err_printf0("Leaked atomic object at ");
} else {
GC_err_printf0("Leaked composite object at ");
}
GC_print_heap_obj(p);
GC_err_printf0("\n");
GC_free(p);
GC_leaked[i] = 0;
}
GC_n_leaked = 0;
printing_errors = FALSE;
}
# define FOUND_FREE(hblk, word_no) \
{ \
GC_add_leaked((ptr_t)hblk + WORDS_TO_BYTES(word_no)); \
}
/*
* reclaim phase
*
*/
/*
* Test whether a block is completely empty, i.e. contains no marked
* objects. This does not require the block to be in physical
* memory.
*/
GC_bool GC_block_empty(hhdr)
register hdr * hhdr;
{
/* We treat hb_marks as an array of words here, even if it is */
/* actually an array of bytes. Since we only check for zero, there */
/* are no endian-ness issues. */
register word *p = (word *)(&(hhdr -> hb_marks[0]));
register word * plim =
(word *)(&(hhdr -> hb_marks[MARK_BITS_SZ]));
while (p < plim) {
if (*p++) return(FALSE);
}
return(TRUE);
}
/* The following functions sometimes return a DONT_KNOW value. */
#define DONT_KNOW 2
#ifdef SMALL_CONFIG
# define GC_block_nearly_full1(hhdr, pat1) DONT_KNOW
# define GC_block_nearly_full3(hhdr, pat1, pat2) DONT_KNOW
# define GC_block_nearly_full(hhdr) DONT_KNOW
#endif
#if !defined(SMALL_CONFIG) && defined(USE_MARK_BYTES)
# define GC_block_nearly_full1(hhdr, pat1) GC_block_nearly_full(hhdr)
# define GC_block_nearly_full3(hhdr, pat1, pat2) GC_block_nearly_full(hhdr)
GC_bool GC_block_nearly_full(hhdr)
register hdr * hhdr;
{
/* We again treat hb_marks as an array of words, even though it */
/* isn't. We first sum up all the words, resulting in a word */
/* containing 4 or 8 separate partial sums. */
/* We then sum the bytes in the word of partial sums. */
/* This is still endian independant. This fails if the partial */
/* sums can overflow. */
# if (BYTES_TO_WORDS(MARK_BITS_SZ)) >= 256
--> potential overflow; fix the code
# endif
register word *p = (word *)(&(hhdr -> hb_marks[0]));
register word * plim =
(word *)(&(hhdr -> hb_marks[MARK_BITS_SZ]));
word sum_vector = 0;
unsigned sum;
while (p < plim) {
sum_vector += *p;
++p;
}
sum = 0;
while (sum_vector > 0) {
sum += sum_vector & 0xff;
sum_vector >>= 8;
}
return (sum > BYTES_TO_WORDS(7*HBLKSIZE/8)/(hhdr -> hb_sz));
}
#endif /* USE_MARK_BYTES */
#if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
/*
* Test whether nearly all of the mark words consist of the same
* repeating pattern.
*/
#define FULL_THRESHOLD (MARK_BITS_SZ/16)
GC_bool GC_block_nearly_full1(hhdr, pat1)
hdr *hhdr;
word pat1;
{
unsigned i;
unsigned misses = 0;
GC_ASSERT((MARK_BITS_SZ & 1) == 0);
for (i = 0; i < MARK_BITS_SZ; ++i) {
if ((hhdr -> hb_marks[i] | ~pat1) != ONES) {
if (++misses > FULL_THRESHOLD) return FALSE;
}
}
return TRUE;
}
/*
* Test whether the same repeating 3 word pattern occurs in nearly
* all the mark bit slots.
* This is used as a heuristic, so we're a bit sloppy and ignore
* the last one or two words.
*/
GC_bool GC_block_nearly_full3(hhdr, pat1, pat2, pat3)
hdr *hhdr;
word pat1, pat2, pat3;
{
unsigned i;
unsigned misses = 0;
if (MARK_BITS_SZ < 4) {
return DONT_KNOW;
}
for (i = 0; i < MARK_BITS_SZ - 2; i += 3) {
if ((hhdr -> hb_marks[i] | ~pat1) != ONES) {
if (++misses > FULL_THRESHOLD) return FALSE;
}
if ((hhdr -> hb_marks[i+1] | ~pat2) != ONES) {
if (++misses > FULL_THRESHOLD) return FALSE;
}
if ((hhdr -> hb_marks[i+2] | ~pat3) != ONES) {
if (++misses > FULL_THRESHOLD) return FALSE;
}
}
return TRUE;
}
/* Check whether a small object block is nearly full by looking at only */
/* the mark bits. */
/* We manually precomputed the mark bit patterns that need to be */
/* checked for, and we give up on the ones that are unlikely to occur, */
/* or have period > 3. */
/* This would be a lot easier with a mark bit per object instead of per */
/* word, but that would rewuire computing object numbers in the mark */
/* loop, which would require different data structures ... */
GC_bool GC_block_nearly_full(hhdr)
hdr *hhdr;
{
int sz = hhdr -> hb_sz;
# if CPP_WORDSZ != 32 && CPP_WORDSZ != 64
return DONT_KNOW; /* Shouldn't be used in any standard config. */
# endif
# if CPP_WORDSZ == 32
switch(sz) {
case 1:
return GC_block_nearly_full1(hhdr, 0xffffffffl);
case 2:
return GC_block_nearly_full1(hhdr, 0x55555555l);
case 4:
return GC_block_nearly_full1(hhdr, 0x11111111l);
case 6:
return GC_block_nearly_full3(hhdr, 0x41041041l,
0x10410410l,
0x04104104l);
case 8:
return GC_block_nearly_full1(hhdr, 0x01010101l);
case 12:
return GC_block_nearly_full3(hhdr, 0x01001001l,
0x10010010l,
0x00100100l);
case 16:
return GC_block_nearly_full1(hhdr, 0x00010001l);
case 32:
return GC_block_nearly_full1(hhdr, 0x00000001l);
default:
return DONT_KNOW;
}
# endif
# if CPP_WORDSZ == 64
switch(sz) {
case 1:
return GC_block_nearly_full1(hhdr, 0xffffffffffffffffl);
case 2:
return GC_block_nearly_full1(hhdr, 0x5555555555555555l);
case 4:
return GC_block_nearly_full1(hhdr, 0x1111111111111111l);
case 6:
return GC_block_nearly_full3(hhdr, 0x1041041041041041l,
0x4104104104104104l,
0x0410410410410410l);
case 8:
return GC_block_nearly_full1(hhdr, 0x0101010101010101l);
case 12:
return GC_block_nearly_full3(hhdr, 0x1001001001001001l,
0x0100100100100100l,
0x0010010010010010l);
case 16:
return GC_block_nearly_full1(hhdr, 0x0001000100010001l);
case 32:
return GC_block_nearly_full1(hhdr, 0x0000000100000001l);
default:
return DONT_KNOW;
}
# endif
}
#endif /* !SMALL_CONFIG && !USE_MARK_BYTES */
/* We keep track of reclaimed memory if we are either asked to, or */
/* we are using the parallel marker. In the latter case, we assume */
/* that most allocation goes through GC_malloc_many for scalability. */
/* GC_malloc_many needs the count anyway. */
# if defined(GATHERSTATS) || defined(PARALLEL_MARK)
# define INCR_WORDS(sz) n_words_found += (sz)
# define COUNT_PARAM , count
# define COUNT_ARG , count
# define COUNT_DECL signed_word * count;
# define NWORDS_DECL signed_word n_words_found = 0;
# define COUNT_UPDATE *count += n_words_found;
# define MEM_FOUND_ADDR , &GC_mem_found
# else
# define INCR_WORDS(sz)
# define COUNT_PARAM
# define COUNT_ARG
# define COUNT_DECL
# define NWORDS_DECL
# define COUNT_UPDATE
# define MEM_FOUND_ADDR
# endif
/*
* Restore unmarked small objects in h of size sz to the object
* free list. Returns the new list.
* Clears unmarked objects.
*/
/*ARGSUSED*/
ptr_t GC_reclaim_clear(hbp, hhdr, sz, list COUNT_PARAM)
register struct hblk *hbp; /* ptr to current heap block */
register hdr * hhdr;
register ptr_t list;
register word sz;
COUNT_DECL
{
register int word_no;
register word *p, *q, *plim;
NWORDS_DECL
GC_ASSERT(hhdr == GC_find_header((ptr_t)hbp));
p = (word *)(hbp->hb_body);
word_no = 0;
plim = (word *)((((word)hbp) + HBLKSIZE)
- WORDS_TO_BYTES(sz));
/* go through all words in block */
while( p <= plim ) {
if( mark_bit_from_hdr(hhdr, word_no) ) {
p += sz;
} else {
INCR_WORDS(sz);
/* object is available - put on list */
obj_link(p) = list;
list = ((ptr_t)p);
/* Clear object, advance p to next object in the process */
q = p + sz;
# ifdef USE_MARK_BYTES
GC_ASSERT(!(sz & 1)
&& !((word)p & (2 * sizeof(word) - 1)));
p[1] = 0;
p += 2;
while (p < q) {
CLEAR_DOUBLE(p);
p += 2;
}
# else
p++; /* Skip link field */
while (p < q) {
*p++ = 0;
}
# endif
}
word_no += sz;
}
COUNT_UPDATE
return(list);
}
#if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
/*
* A special case for 2 word composite objects (e.g. cons cells):
*/
/*ARGSUSED*/
ptr_t GC_reclaim_clear2(hbp, hhdr, list COUNT_PARAM)
register struct hblk *hbp; /* ptr to current heap block */
hdr * hhdr;
register ptr_t list;
COUNT_DECL
{
register word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p, *plim;
register word mark_word;
register int i;
NWORDS_DECL
# define DO_OBJ(start_displ) \
if (!(mark_word & ((word)1 << start_displ))) { \
p[start_displ] = (word)list; \
list = (ptr_t)(p+start_displ); \
p[start_displ+1] = 0; \
INCR_WORDS(2); \
}
p = (word *)(hbp->hb_body);
plim = (word *)(((word)hbp) + HBLKSIZE);
/* go through all words in block */
while( p < plim ) {
mark_word = *mark_word_addr++;
for (i = 0; i < WORDSZ; i += 8) {
DO_OBJ(0);
DO_OBJ(2);
DO_OBJ(4);
DO_OBJ(6);
p += 8;
mark_word >>= 8;
}
}
COUNT_UPDATE
return(list);
# undef DO_OBJ
}
/*
* Another special case for 4 word composite objects:
*/
/*ARGSUSED*/
ptr_t GC_reclaim_clear4(hbp, hhdr, list COUNT_PARAM)
register struct hblk *hbp; /* ptr to current heap block */
hdr * hhdr;
register ptr_t list;
COUNT_DECL
{
register word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p, *plim;
register word mark_word;
NWORDS_DECL
# define DO_OBJ(start_displ) \
if (!(mark_word & ((word)1 << start_displ))) { \
p[start_displ] = (word)list; \
list = (ptr_t)(p+start_displ); \
p[start_displ+1] = 0; \
CLEAR_DOUBLE(p + start_displ + 2); \
INCR_WORDS(4); \
}
p = (word *)(hbp->hb_body);
plim = (word *)(((word)hbp) + HBLKSIZE);
/* go through all words in block */
while( p < plim ) {
mark_word = *mark_word_addr++;
DO_OBJ(0);
DO_OBJ(4);
DO_OBJ(8);
DO_OBJ(12);
DO_OBJ(16);
DO_OBJ(20);
DO_OBJ(24);
DO_OBJ(28);
# if CPP_WORDSZ == 64
DO_OBJ(32);
DO_OBJ(36);
DO_OBJ(40);
DO_OBJ(44);
DO_OBJ(48);
DO_OBJ(52);
DO_OBJ(56);
DO_OBJ(60);
# endif
p += WORDSZ;
}
COUNT_UPDATE
return(list);
# undef DO_OBJ
}
#endif /* !SMALL_CONFIG && !USE_MARK_BYTES */
/* The same thing, but don't clear objects: */
/*ARGSUSED*/
ptr_t GC_reclaim_uninit(hbp, hhdr, sz, list COUNT_PARAM)
register struct hblk *hbp; /* ptr to current heap block */
register hdr * hhdr;
register ptr_t list;
register word sz;
COUNT_DECL
{
register int word_no = 0;
register word *p, *plim;
NWORDS_DECL
p = (word *)(hbp->hb_body);
plim = (word *)((((word)hbp) + HBLKSIZE)
- WORDS_TO_BYTES(sz));
/* go through all words in block */
while( p <= plim ) {
if( !mark_bit_from_hdr(hhdr, word_no) ) {
INCR_WORDS(sz);
/* object is available - put on list */
obj_link(p) = list;
list = ((ptr_t)p);
}
p += sz;
word_no += sz;
}
COUNT_UPDATE
return(list);
}
/* Don't really reclaim objects, just check for unmarked ones: */
/*ARGSUSED*/
void GC_reclaim_check(hbp, hhdr, sz)
register struct hblk *hbp; /* ptr to current heap block */
register hdr * hhdr;
register word sz;
{
register int word_no = 0;
register word *p, *plim;
# ifdef GATHERSTATS
register int n_words_found = 0;
# endif
p = (word *)(hbp->hb_body);
plim = (word *)((((word)hbp) + HBLKSIZE)
- WORDS_TO_BYTES(sz));
/* go through all words in block */
while( p <= plim ) {
if( !mark_bit_from_hdr(hhdr, word_no) ) {
FOUND_FREE(hbp, word_no);
}
p += sz;
word_no += sz;
}
}
#if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
/*
* Another special case for 2 word atomic objects:
*/
/*ARGSUSED*/
ptr_t GC_reclaim_uninit2(hbp, hhdr, list COUNT_PARAM)
register struct hblk *hbp; /* ptr to current heap block */
hdr * hhdr;
register ptr_t list;
COUNT_DECL
{
register word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p, *plim;
register word mark_word;
register int i;
NWORDS_DECL
# define DO_OBJ(start_displ) \
if (!(mark_word & ((word)1 << start_displ))) { \
p[start_displ] = (word)list; \
list = (ptr_t)(p+start_displ); \
INCR_WORDS(2); \
}
p = (word *)(hbp->hb_body);
plim = (word *)(((word)hbp) + HBLKSIZE);
/* go through all words in block */
while( p < plim ) {
mark_word = *mark_word_addr++;
for (i = 0; i < WORDSZ; i += 8) {
DO_OBJ(0);
DO_OBJ(2);
DO_OBJ(4);
DO_OBJ(6);
p += 8;
mark_word >>= 8;
}
}
COUNT_UPDATE
return(list);
# undef DO_OBJ
}
/*
* Another special case for 4 word atomic objects:
*/
/*ARGSUSED*/
ptr_t GC_reclaim_uninit4(hbp, hhdr, list COUNT_PARAM)
register struct hblk *hbp; /* ptr to current heap block */
hdr * hhdr;
register ptr_t list;
COUNT_DECL
{
register word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p, *plim;
register word mark_word;
NWORDS_DECL
# define DO_OBJ(start_displ) \
if (!(mark_word & ((word)1 << start_displ))) { \
p[start_displ] = (word)list; \
list = (ptr_t)(p+start_displ); \
INCR_WORDS(4); \
}
p = (word *)(hbp->hb_body);
plim = (word *)(((word)hbp) + HBLKSIZE);
/* go through all words in block */
while( p < plim ) {
mark_word = *mark_word_addr++;
DO_OBJ(0);
DO_OBJ(4);
DO_OBJ(8);
DO_OBJ(12);
DO_OBJ(16);
DO_OBJ(20);
DO_OBJ(24);
DO_OBJ(28);
# if CPP_WORDSZ == 64
DO_OBJ(32);
DO_OBJ(36);
DO_OBJ(40);
DO_OBJ(44);
DO_OBJ(48);
DO_OBJ(52);
DO_OBJ(56);
DO_OBJ(60);
# endif
p += WORDSZ;
}
COUNT_UPDATE
return(list);
# undef DO_OBJ
}
/* Finally the one word case, which never requires any clearing: */
/*ARGSUSED*/
ptr_t GC_reclaim1(hbp, hhdr, list COUNT_PARAM)
register struct hblk *hbp; /* ptr to current heap block */
hdr * hhdr;
register ptr_t list;
COUNT_DECL
{
register word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p, *plim;
register word mark_word;
register int i;
NWORDS_DECL
# define DO_OBJ(start_displ) \
if (!(mark_word & ((word)1 << start_displ))) { \
p[start_displ] = (word)list; \
list = (ptr_t)(p+start_displ); \
INCR_WORDS(1); \
}
p = (word *)(hbp->hb_body);
plim = (word *)(((word)hbp) + HBLKSIZE);
/* go through all words in block */
while( p < plim ) {
mark_word = *mark_word_addr++;
for (i = 0; i < WORDSZ; i += 4) {
DO_OBJ(0);
DO_OBJ(1);
DO_OBJ(2);
DO_OBJ(3);
p += 4;
mark_word >>= 4;
}
}
COUNT_UPDATE
return(list);
# undef DO_OBJ
}
#endif /* !SMALL_CONFIG && !USE_MARK_BYTES */
/*
* Generic procedure to rebuild a free list in hbp.
* Also called directly from GC_malloc_many.
*/
ptr_t GC_reclaim_generic(hbp, hhdr, sz, init, list COUNT_PARAM)
struct hblk *hbp; /* ptr to current heap block */
hdr * hhdr;
GC_bool init;
ptr_t list;
word sz;
COUNT_DECL
{
ptr_t result = list;
GC_ASSERT(GC_find_header((ptr_t)hbp) == hhdr);
GC_remove_protection(hbp, 1, (hhdr)->hb_descr == 0 /* Pointer-free? */);
if (init) {
switch(sz) {
# if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
case 1:
/* We now issue the hint even if GC_nearly_full returned */
/* DONT_KNOW. */
result = GC_reclaim1(hbp, hhdr, list COUNT_ARG);
break;
case 2:
result = GC_reclaim_clear2(hbp, hhdr, list COUNT_ARG);
break;
case 4:
result = GC_reclaim_clear4(hbp, hhdr, list COUNT_ARG);
break;
# endif /* !SMALL_CONFIG && !USE_MARK_BYTES */
default:
result = GC_reclaim_clear(hbp, hhdr, sz, list COUNT_ARG);
break;
}
} else {
GC_ASSERT((hhdr)->hb_descr == 0 /* Pointer-free block */);
switch(sz) {
# if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
case 1:
result = GC_reclaim1(hbp, hhdr, list COUNT_ARG);
break;
case 2:
result = GC_reclaim_uninit2(hbp, hhdr, list COUNT_ARG);
break;
case 4:
result = GC_reclaim_uninit4(hbp, hhdr, list COUNT_ARG);
break;
# endif /* !SMALL_CONFIG && !USE_MARK_BYTES */
default:
result = GC_reclaim_uninit(hbp, hhdr, sz, list COUNT_ARG);
break;
}
}
if (IS_UNCOLLECTABLE(hhdr -> hb_obj_kind)) GC_set_hdr_marks(hhdr);
return result;
}
/*
* Restore unmarked small objects in the block pointed to by hbp
* to the appropriate object free list.
* If entirely empty blocks are to be completely deallocated, then
* caller should perform that check.
*/
void GC_reclaim_small_nonempty_block(hbp, report_if_found COUNT_PARAM)
register struct hblk *hbp; /* ptr to current heap block */
int report_if_found; /* Abort if a reclaimable object is found */
COUNT_DECL
{
hdr *hhdr = HDR(hbp);
word sz = hhdr -> hb_sz;
int kind = hhdr -> hb_obj_kind;
struct obj_kind * ok = &GC_obj_kinds[kind];
ptr_t * flh = &(ok -> ok_freelist[sz]);
hhdr -> hb_last_reclaimed = (unsigned short) GC_gc_no;
if (report_if_found) {
GC_reclaim_check(hbp, hhdr, sz);
} else {
*flh = GC_reclaim_generic(hbp, hhdr, sz,
(ok -> ok_init || GC_debugging_started),
*flh MEM_FOUND_ADDR);
}
}
/*
* Restore an unmarked large object or an entirely empty blocks of small objects
* to the heap block free list.
* Otherwise enqueue the block for later processing
* by GC_reclaim_small_nonempty_block.
* If report_if_found is TRUE, then process any block immediately, and
* simply report free objects; do not actually reclaim them.
*/
# if defined(__STDC__) || defined(__cplusplus)
void GC_reclaim_block(register struct hblk *hbp, word report_if_found)
# else
void GC_reclaim_block(hbp, report_if_found)
register struct hblk *hbp; /* ptr to current heap block */
word report_if_found; /* Abort if a reclaimable object is found */
# endif
{
register hdr * hhdr;
register word sz; /* size of objects in current block */
register struct obj_kind * ok;
struct hblk ** rlh;
hhdr = HDR(hbp);
sz = hhdr -> hb_sz;
ok = &GC_obj_kinds[hhdr -> hb_obj_kind];
if( sz > MAXOBJSZ ) { /* 1 big object */
if( !mark_bit_from_hdr(hhdr, 0) ) {
if (report_if_found) {
FOUND_FREE(hbp, 0);
} else {
word blocks = OBJ_SZ_TO_BLOCKS(sz);
if (blocks > 1) {
GC_large_allocd_bytes -= blocks * HBLKSIZE;
}
# ifdef GATHERSTATS
GC_mem_found += sz;
# endif
GC_freehblk(hbp);
}
}
} else {
GC_bool empty = GC_block_empty(hhdr);
if (report_if_found) {
GC_reclaim_small_nonempty_block(hbp, (int)report_if_found
MEM_FOUND_ADDR);
} else if (empty) {
# ifdef GATHERSTATS
GC_mem_found += BYTES_TO_WORDS(HBLKSIZE);
# endif
GC_freehblk(hbp);
} else if (TRUE != GC_block_nearly_full(hhdr)){
/* group of smaller objects, enqueue the real work */
rlh = &(ok -> ok_reclaim_list[sz]);
hhdr -> hb_next = *rlh;
*rlh = hbp;
} /* else not worth salvaging. */
/* We used to do the nearly_full check later, but we */
/* already have the right cache context here. Also */
/* doing it here avoids some silly lock contention in */
/* GC_malloc_many. */
}
}
#if !defined(NO_DEBUGGING)
/* Routines to gather and print heap block info */
/* intended for debugging. Otherwise should be called */
/* with lock. */
struct Print_stats
{
size_t number_of_blocks;
size_t total_bytes;
};
#ifdef USE_MARK_BYTES
/* Return the number of set mark bits in the given header */
int GC_n_set_marks(hhdr)
hdr * hhdr;
{
register int result = 0;
register int i;
for (i = 0; i < MARK_BITS_SZ; i++) {
result += hhdr -> hb_marks[i];
}
return(result);
}
#else
/* Number of set bits in a word. Not performance critical. */
static int set_bits(n)
word n;
{
register word m = n;
register int result = 0;
while (m > 0) {
if (m & 1) result++;
m >>= 1;
}
return(result);
}
/* Return the number of set mark bits in the given header */
int GC_n_set_marks(hhdr)
hdr * hhdr;
{
register int result = 0;
register int i;
for (i = 0; i < MARK_BITS_SZ; i++) {
result += set_bits(hhdr -> hb_marks[i]);
}
return(result);
}
#endif /* !USE_MARK_BYTES */
/*ARGSUSED*/
# if defined(__STDC__) || defined(__cplusplus)
void GC_print_block_descr(struct hblk *h, word dummy)
# else
void GC_print_block_descr(h, dummy)
struct hblk *h;
word dummy;
# endif
{
register hdr * hhdr = HDR(h);
register size_t bytes = WORDS_TO_BYTES(hhdr -> hb_sz);
struct Print_stats *ps;
GC_printf3("(%lu:%lu,%lu)", (unsigned long)(hhdr -> hb_obj_kind),
(unsigned long)bytes,
(unsigned long)(GC_n_set_marks(hhdr)));
bytes += HBLKSIZE-1;
bytes &= ~(HBLKSIZE-1);
ps = (struct Print_stats *)dummy;
ps->total_bytes += bytes;
ps->number_of_blocks++;
}
void GC_print_block_list()
{
struct Print_stats pstats;
GC_printf1("(kind(0=ptrfree,1=normal,2=unc.,%lu=stubborn):size_in_bytes, #_marks_set)\n", STUBBORN);
pstats.number_of_blocks = 0;
pstats.total_bytes = 0;
GC_apply_to_all_blocks(GC_print_block_descr, (word)&pstats);
GC_printf2("\nblocks = %lu, bytes = %lu\n",
(unsigned long)pstats.number_of_blocks,
(unsigned long)pstats.total_bytes);
}
#endif /* NO_DEBUGGING */
/*
* Clear all obj_link pointers in the list of free objects *flp.
* Clear *flp.
* This must be done before dropping a list of free gcj-style objects,
* since may otherwise end up with dangling "descriptor" pointers.
* It may help for other pointer-containing objects.
*/
void GC_clear_fl_links(flp)
ptr_t *flp;
{
ptr_t next = *flp;
while (0 != next) {
*flp = 0;
flp = &(obj_link(next));
next = *flp;
}
}
/*
* Perform GC_reclaim_block on the entire heap, after first clearing
* small object free lists (if we are not just looking for leaks).
*/
void GC_start_reclaim(report_if_found)
int report_if_found; /* Abort if a GC_reclaimable object is found */
{
int kind;
# if defined(PARALLEL_MARK) || defined(THREAD_LOCAL_ALLOC)
GC_ASSERT(0 == GC_fl_builder_count);
# endif
/* Clear reclaim- and free-lists */
for (kind = 0; kind < GC_n_kinds; kind++) {
ptr_t *fop;
ptr_t *lim;
struct hblk ** rlp;
struct hblk ** rlim;
struct hblk ** rlist = GC_obj_kinds[kind].ok_reclaim_list;
GC_bool should_clobber = (GC_obj_kinds[kind].ok_descriptor != 0);
if (rlist == 0) continue; /* This kind not used. */
if (!report_if_found) {
lim = &(GC_obj_kinds[kind].ok_freelist[MAXOBJSZ+1]);
for( fop = GC_obj_kinds[kind].ok_freelist; fop < lim; fop++ ) {
if (*fop != 0) {
if (should_clobber) {
GC_clear_fl_links(fop);
} else {
*fop = 0;
}
}
}
} /* otherwise free list objects are marked, */
/* and its safe to leave them */
rlim = rlist + MAXOBJSZ+1;
for( rlp = rlist; rlp < rlim; rlp++ ) {
*rlp = 0;
}
}
# ifdef PRINTBLOCKS
GC_printf0("GC_reclaim: current block sizes:\n");
GC_print_block_list();
# endif
/* Go through all heap blocks (in hblklist) and reclaim unmarked objects */
/* or enqueue the block for later processing. */
GC_apply_to_all_blocks(GC_reclaim_block, (word)report_if_found);
# ifdef EAGER_SWEEP
/* This is a very stupid thing to do. We make it possible anyway, */
/* so that you can convince yourself that it really is very stupid. */
GC_reclaim_all((GC_stop_func)0, FALSE);
# endif
# if defined(PARALLEL_MARK) || defined(THREAD_LOCAL_ALLOC)
GC_ASSERT(0 == GC_fl_builder_count);
# endif
}
/*
* Sweep blocks of the indicated object size and kind until either the
* appropriate free list is nonempty, or there are no more blocks to
* sweep.
*/
void GC_continue_reclaim(sz, kind)
word sz; /* words */
int kind;
{
register hdr * hhdr;
register struct hblk * hbp;
register struct obj_kind * ok = &(GC_obj_kinds[kind]);
struct hblk ** rlh = ok -> ok_reclaim_list;
ptr_t *flh = &(ok -> ok_freelist[sz]);
if (rlh == 0) return; /* No blocks of this kind. */
rlh += sz;
while ((hbp = *rlh) != 0) {
hhdr = HDR(hbp);
*rlh = hhdr -> hb_next;
GC_reclaim_small_nonempty_block(hbp, FALSE MEM_FOUND_ADDR);
if (*flh != 0) break;
}
}
/*
* Reclaim all small blocks waiting to be reclaimed.
* Abort and return FALSE when/if (*stop_func)() returns TRUE.
* If this returns TRUE, then it's safe to restart the world
* with incorrectly cleared mark bits.
* If ignore_old is TRUE, then reclaim only blocks that have been
* recently reclaimed, and discard the rest.
* Stop_func may be 0.
*/
GC_bool GC_reclaim_all(stop_func, ignore_old)
GC_stop_func stop_func;
GC_bool ignore_old;
{
register word sz;
register int kind;
register hdr * hhdr;
register struct hblk * hbp;
register struct obj_kind * ok;
struct hblk ** rlp;
struct hblk ** rlh;
# ifdef PRINTTIMES
CLOCK_TYPE start_time;
CLOCK_TYPE done_time;
GET_TIME(start_time);
# endif
for (kind = 0; kind < GC_n_kinds; kind++) {
ok = &(GC_obj_kinds[kind]);
rlp = ok -> ok_reclaim_list;
if (rlp == 0) continue;
for (sz = 1; sz <= MAXOBJSZ; sz++) {
rlh = rlp + sz;
while ((hbp = *rlh) != 0) {
if (stop_func != (GC_stop_func)0 && (*stop_func)()) {
return(FALSE);
}
hhdr = HDR(hbp);
*rlh = hhdr -> hb_next;
if (!ignore_old || hhdr -> hb_last_reclaimed == GC_gc_no - 1) {
/* It's likely we'll need it this time, too */
/* It's been touched recently, so this */
/* shouldn't trigger paging. */
GC_reclaim_small_nonempty_block(hbp, FALSE MEM_FOUND_ADDR);
}
}
}
}
# ifdef PRINTTIMES
GET_TIME(done_time);
GC_printf1("Disposing of reclaim lists took %lu msecs\n",
MS_TIME_DIFF(done_time,start_time));
# endif
return(TRUE);
}
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