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reclaim.c
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reclaim.c
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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) 1999-2004 Hewlett-Packard Development Company, L.P.
* Copyright (c) 2009-2022 Ivan Maidanski
*
* 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 "private/gc_priv.h"
#ifdef ENABLE_DISCLAIM
# include "gc/gc_disclaim.h"
#endif
GC_INNER signed_word GC_bytes_found = 0;
/* Number of bytes of memory reclaimed */
/* minus the number of bytes originally */
/* on free lists which we had to drop. */
#if defined(PARALLEL_MARK)
GC_INNER signed_word GC_fl_builder_count = 0;
/* Number of threads currently building free lists without */
/* holding the allocator lock. It is not safe to collect if */
/* this is nonzero. Also, together with the mark lock, it is */
/* used as a semaphore during marker threads startup. */
#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 allocator lock. */
#ifndef MAX_LEAKED
# define MAX_LEAKED 40
#endif
STATIC ptr_t GC_leaked[MAX_LEAKED] = { NULL };
STATIC unsigned GC_n_leaked = 0;
#ifdef AO_HAVE_store
GC_INNER volatile AO_t GC_have_errors = 0;
#else
GC_INNER GC_bool GC_have_errors = FALSE;
#endif
#if !defined(EAGER_SWEEP) && defined(ENABLE_DISCLAIM)
STATIC void GC_reclaim_unconditionally_marked(void);
#endif
GC_INLINE void GC_add_leaked(ptr_t leaked)
{
GC_ASSERT(I_HOLD_LOCK());
# ifndef SHORT_DBG_HDRS
if (GC_findleak_delay_free && !GC_check_leaked(leaked))
return;
# endif
GC_SET_HAVE_ERRORS();
if (GC_n_leaked < MAX_LEAKED) {
GC_leaked[GC_n_leaked++] = leaked;
/* Make sure it's not reclaimed this cycle */
GC_set_mark_bit(leaked);
}
}
/* Print all objects on the list after printing any smashed objects. */
/* Clear both lists. Called without the allocator lock held. */
GC_INNER void GC_print_all_errors(void)
{
static GC_bool printing_errors = FALSE;
GC_bool have_errors;
unsigned i, n_leaked;
ptr_t leaked[MAX_LEAKED];
LOCK();
if (printing_errors) {
UNLOCK();
return;
}
have_errors = get_have_errors();
printing_errors = TRUE;
n_leaked = GC_n_leaked;
if (n_leaked > 0) {
GC_ASSERT(n_leaked <= MAX_LEAKED);
BCOPY(GC_leaked, leaked, n_leaked * sizeof(ptr_t));
GC_n_leaked = 0;
BZERO(GC_leaked, n_leaked * sizeof(ptr_t));
}
UNLOCK();
if (GC_debugging_started) {
GC_print_all_smashed();
} else {
have_errors = FALSE;
}
if (n_leaked > 0) {
GC_err_printf("Found %u leaked objects:\n", n_leaked);
have_errors = TRUE;
}
for (i = 0; i < n_leaked; i++) {
ptr_t p = leaked[i];
# ifndef SKIP_LEAKED_OBJECTS_PRINTING
GC_print_heap_obj(p);
# endif
GC_free(p);
}
if (have_errors
# ifndef GC_ABORT_ON_LEAK
&& GETENV("GC_ABORT_ON_LEAK") != NULL
# endif
) {
ABORT("Leaked or smashed objects encountered");
}
LOCK();
printing_errors = FALSE;
UNLOCK();
}
/*
* 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_INNER GC_bool GC_block_empty(const hdr *hhdr)
{
return 0 == hhdr -> hb_n_marks;
}
STATIC GC_bool GC_block_nearly_full(const hdr *hhdr, size_t sz)
{
return hhdr -> hb_n_marks > HBLK_OBJS(sz) * 7 / 8;
}
/* TODO: This should perhaps again be specialized for USE_MARK_BYTES */
/* and USE_MARK_BITS cases. */
GC_INLINE ptr_t GC_clear_block(ptr_t q, size_t sz, word *pcount)
{
ptr_t *p = (ptr_t *)q;
ptr_t plim = q + sz;
/* Clear object, advance p to next object in the process. */
# ifdef USE_MARK_BYTES
GC_ASSERT((sz & 1) == 0);
GC_ASSERT((ADDR(p) & (2*sizeof(ptr_t)-1)) == 0);
p[1] = NULL; /* but do not clear link field */
for (p += 2; ADDR_LT((ptr_t)p, plim); p += 2) {
CLEAR_DOUBLE(p);
}
# else
p++; /* skip link field */
while (ADDR_LT((ptr_t)p, plim)) {
*p++ = NULL;
}
# endif
*pcount += sz;
return (ptr_t)p;
}
/*
* Restore unmarked small objects in h of size sz to the object
* free list. Returns the new list.
* Clears unmarked objects. Sz is in bytes.
*/
STATIC ptr_t GC_reclaim_clear(struct hblk *hbp, const hdr *hhdr, size_t sz,
ptr_t list, word *pcount)
{
size_t bit_no;
ptr_t p, plim;
GC_ASSERT(hhdr == GC_find_header(hbp));
# ifndef THREADS
GC_ASSERT(sz == hhdr -> hb_sz);
# else
/* Skip the assertion because of a potential race with GC_realloc. */
# endif
GC_ASSERT((sz & (sizeof(ptr_t)-1)) == 0);
/* Go through all objects in the block. */
p = hbp -> hb_body;
plim = p + HBLKSIZE - sz;
for (bit_no = 0; ADDR_GE(plim, p); bit_no += MARK_BIT_OFFSET(sz)) {
if (mark_bit_from_hdr(hhdr, bit_no)) {
p += sz;
} else {
/* The object is available - put it on list. */
obj_link(p) = list;
list = p;
FREE_PROFILER_HOOK(p);
p = GC_clear_block(p, sz, pcount);
}
}
return list;
}
/* The same thing, but don't clear objects: */
STATIC ptr_t GC_reclaim_uninit(struct hblk *hbp, const hdr *hhdr, size_t sz,
ptr_t list, word *pcount)
{
size_t bit_no;
word n_bytes_found = 0;
ptr_t p, plim;
# ifndef THREADS
GC_ASSERT(sz == hhdr -> hb_sz);
# endif
/* Go through all objects in the block. */
p = hbp -> hb_body;
plim = (ptr_t)hbp + HBLKSIZE - sz;
for (bit_no = 0; ADDR_GE(plim, p);
bit_no += MARK_BIT_OFFSET(sz), p += sz) {
if (!mark_bit_from_hdr(hhdr, bit_no)) {
n_bytes_found += sz;
/* The object is available - put it on list. */
obj_link(p) = list;
list = p;
FREE_PROFILER_HOOK(p);
}
}
*pcount += n_bytes_found;
return list;
}
#ifdef ENABLE_DISCLAIM
/* Call reclaim notifier for block's kind on each unmarked object in */
/* block, all within a pair of corresponding enter/leave callbacks. */
STATIC ptr_t GC_disclaim_and_reclaim(struct hblk *hbp, hdr *hhdr, size_t sz,
ptr_t list, word *pcount)
{
size_t bit_no;
ptr_t p, plim;
int (GC_CALLBACK *disclaim)(void *) =
GC_obj_kinds[hhdr -> hb_obj_kind].ok_disclaim_proc;
GC_ASSERT(disclaim != 0);
# ifndef THREADS
GC_ASSERT(sz == hhdr -> hb_sz);
# endif
p = hbp -> hb_body;
plim = p + HBLKSIZE - sz;
for (bit_no = 0; ADDR_GE(plim, p); bit_no += MARK_BIT_OFFSET(sz)) {
if (mark_bit_from_hdr(hhdr, bit_no)) {
p += sz;
} else if (disclaim(p)) {
set_mark_bit_from_hdr(hhdr, bit_no);
INCR_MARKS(hhdr);
p += sz;
} else {
obj_link(p) = list;
list = p;
FREE_PROFILER_HOOK(p);
p = GC_clear_block(p, sz, pcount);
}
}
return list;
}
#endif /* ENABLE_DISCLAIM */
/* Don't really reclaim objects, just check for unmarked ones: */
STATIC void GC_reclaim_check(struct hblk *hbp, const hdr *hhdr, size_t sz)
{
size_t bit_no;
ptr_t p, plim;
# ifndef THREADS
GC_ASSERT(sz == hhdr -> hb_sz);
# endif
/* Go through all objects in the block. */
p = hbp -> hb_body;
plim = p + HBLKSIZE - sz;
for (bit_no = 0; ADDR_GE(plim, p);
bit_no += MARK_BIT_OFFSET(sz), p += sz) {
if (!mark_bit_from_hdr(hhdr, bit_no))
GC_add_leaked(p);
}
}
/* Is a pointer-free block? Same as IS_PTRFREE() macro but uses */
/* unordered atomic access to avoid racing with GC_realloc. */
#ifdef AO_HAVE_load
# define IS_PTRFREE_SAFE(hhdr) (AO_load((AO_t *)&((hhdr) -> hb_descr)) == 0)
#else
/* No race as GC_realloc holds the allocator lock when updating hb_descr. */
# define IS_PTRFREE_SAFE(hhdr) IS_PTRFREE(hhdr)
#endif
/* Generic procedure to rebuild a free list in hbp. Also called */
/* directly from GC_malloc_many. sz is in bytes. */
GC_INNER ptr_t GC_reclaim_generic(struct hblk *hbp, hdr *hhdr, size_t sz,
GC_bool init, ptr_t list, word *pcount)
{
ptr_t result;
# ifndef PARALLEL_MARK
GC_ASSERT(I_HOLD_LOCK());
# endif
GC_ASSERT(GC_find_header(hbp) == hhdr);
# ifndef GC_DISABLE_INCREMENTAL
GC_remove_protection(hbp, 1, IS_PTRFREE_SAFE(hhdr));
# endif
# ifdef ENABLE_DISCLAIM
if ((hhdr -> hb_flags & HAS_DISCLAIM) != 0) {
result = GC_disclaim_and_reclaim(hbp, hhdr, sz, list, pcount);
} else
# endif
/* else */ if (init || GC_debugging_started) {
result = GC_reclaim_clear(hbp, hhdr, sz, list, pcount);
} else {
# ifndef AO_HAVE_load
GC_ASSERT(IS_PTRFREE(hhdr));
# endif
result = GC_reclaim_uninit(hbp, hhdr, sz, list, pcount);
}
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.
*/
STATIC void GC_reclaim_small_nonempty_block(struct hblk *hbp, size_t sz,
GC_bool report_if_found)
{
hdr *hhdr;
GC_ASSERT(I_HOLD_LOCK());
hhdr = HDR(hbp);
hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
if (report_if_found) {
GC_reclaim_check(hbp, hhdr, sz);
} else {
struct obj_kind *ok = &GC_obj_kinds[hhdr -> hb_obj_kind];
void **flh = &(ok -> ok_freelist[BYTES_TO_GRANULES(sz)]);
*flh = GC_reclaim_generic(hbp, hhdr, sz, ok -> ok_init, (ptr_t)(*flh),
(/* unsigned */ word *)&GC_bytes_found);
}
}
#ifdef ENABLE_DISCLAIM
STATIC void GC_disclaim_and_reclaim_or_free_small_block(struct hblk *hbp)
{
hdr *hhdr;
size_t sz;
struct obj_kind *ok;
void **flh;
void *flh_next;
GC_ASSERT(I_HOLD_LOCK());
hhdr = HDR(hbp);
sz = hhdr -> hb_sz;
ok = &GC_obj_kinds[hhdr -> hb_obj_kind];
flh = &(ok -> ok_freelist[BYTES_TO_GRANULES(sz)]);
hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
flh_next = GC_reclaim_generic(hbp, hhdr, sz, ok -> ok_init, (ptr_t)(*flh),
(/* unsigned */ word *)&GC_bytes_found);
if (hhdr -> hb_n_marks) {
*flh = flh_next;
} else {
GC_ASSERT(hbp == hhdr -> hb_block);
GC_bytes_found += (signed_word)HBLKSIZE;
GC_freehblk(hbp);
}
}
#endif /* ENABLE_DISCLAIM */
/* 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. */
STATIC void GC_CALLBACK GC_reclaim_block(struct hblk *hbp,
void *report_if_found)
{
hdr *hhdr;
size_t sz; /* size of objects in current block */
struct obj_kind *ok;
GC_ASSERT(I_HOLD_LOCK());
# if defined(CPPCHECK)
GC_noop1_ptr(report_if_found);
# endif
hhdr = HDR(hbp);
ok = &GC_obj_kinds[hhdr -> hb_obj_kind];
# ifdef AO_HAVE_load
/* Atomic access is used to avoid racing with GC_realloc. */
sz = AO_load(&(hhdr -> hb_sz));
# else
/* No race as GC_realloc holds the allocator lock while */
/* updating hb_sz. */
sz = hhdr -> hb_sz;
# endif
if (sz > MAXOBJBYTES) { /* 1 big object */
if (!mark_bit_from_hdr(hhdr, 0)) {
if (report_if_found) {
GC_ASSERT(hbp == hhdr -> hb_block);
GC_add_leaked((ptr_t)hbp);
} else {
# ifdef ENABLE_DISCLAIM
if (EXPECT(hhdr -> hb_flags & HAS_DISCLAIM, 0)) {
if (ok -> ok_disclaim_proc(hbp)) {
/* Not disclaimed => resurrect the object. */
set_mark_bit_from_hdr(hhdr, 0);
goto in_use;
}
}
# endif
GC_ASSERT(hbp == hhdr -> hb_block);
if (sz > HBLKSIZE) {
GC_large_allocd_bytes -= HBLKSIZE * OBJ_SZ_TO_BLOCKS(sz);
}
GC_bytes_found += (signed_word)sz;
GC_freehblk(hbp);
FREE_PROFILER_HOOK(hbp);
}
} else {
# ifdef ENABLE_DISCLAIM
in_use:
# endif
if (IS_PTRFREE_SAFE(hhdr)) {
GC_atomic_in_use += sz;
} else {
GC_composite_in_use += sz;
}
}
} else {
GC_bool empty = GC_block_empty(hhdr);
# ifdef PARALLEL_MARK
/* Count can be low or one too high because we sometimes */
/* have to ignore decrements. Objects can also potentially */
/* be repeatedly marked by each marker. */
/* Here we assume 3 markers at most, but this is extremely */
/* unlikely to fail spuriously with more. And if it does, it */
/* should be looked at. */
GC_ASSERT(sz != 0 && (GC_markers_m1 > 1 ? 3 : GC_markers_m1 + 1)
* (HBLKSIZE/sz + 1) + 16 >= hhdr->hb_n_marks);
# else
GC_ASSERT(sz * hhdr -> hb_n_marks <= HBLKSIZE);
# endif
# ifdef VALGRIND_TRACKING
/* Call GC_free_profiler_hook() on freed objects so that */
/* a profiling tool could track the allocations. */
{
ptr_t p = hbp -> hb_body;
ptr_t plim = p + HBLKSIZE - sz;
size_t bit_no;
for (bit_no = 0; ADDR_GE(plim, p);
bit_no += MARK_BIT_OFFSET(sz), p += sz) {
if (!mark_bit_from_hdr(hhdr, bit_no))
FREE_PROFILER_HOOK(p);
}
}
# endif
GC_ASSERT(hbp == hhdr -> hb_block);
if (report_if_found) {
GC_reclaim_small_nonempty_block(hbp, sz,
TRUE /* report_if_found */);
} else if (empty) {
# ifdef ENABLE_DISCLAIM
if ((hhdr -> hb_flags & HAS_DISCLAIM) != 0) {
GC_disclaim_and_reclaim_or_free_small_block(hbp);
} else
# endif
/* else */ {
GC_bytes_found += (signed_word)HBLKSIZE;
GC_freehblk(hbp);
FREE_PROFILER_HOOK(hbp);
}
} else if (GC_find_leak || !GC_block_nearly_full(hhdr, sz)) {
/* group of smaller objects, enqueue the real work */
struct hblk **rlh = ok -> ok_reclaim_list;
if (rlh != NULL) {
rlh += BYTES_TO_GRANULES(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 (IS_PTRFREE_SAFE(hhdr)) {
GC_atomic_in_use += (word)sz * hhdr -> hb_n_marks;
} else {
GC_composite_in_use += (word)sz * hhdr -> hb_n_marks;
}
}
}
#if !defined(NO_DEBUGGING)
/* Routines to gather and print heap block info intended for */
/* debugging. Otherwise should be called with the allocator lock */
/* held. */
struct Print_stats
{
size_t number_of_blocks;
size_t total_bytes;
};
EXTERN_C_BEGIN /* to avoid "no previous prototype" clang warning */
unsigned GC_n_set_marks(const hdr *);
EXTERN_C_END
# ifdef USE_MARK_BYTES
/* Return the number of set mark bits in the given header. */
/* Remains externally visible as used by GNU GCJ currently. */
/* There could be a race between GC_clear_hdr_marks and this */
/* function but the latter is for a debug purpose. */
GC_ATTR_NO_SANITIZE_THREAD
unsigned GC_n_set_marks(const hdr *hhdr)
{
unsigned result = 0;
size_t i;
size_t offset = MARK_BIT_OFFSET(hhdr -> hb_sz);
size_t limit = FINAL_MARK_BIT(hhdr -> hb_sz);
for (i = 0; i < limit; i += offset) {
result += (unsigned)(hhdr -> hb_marks[i]);
}
GC_ASSERT(hhdr -> hb_marks[limit]); /* the one set past the end */
return result;
}
# else
/* Number of set bits in a word. Not performance critical. */
static unsigned count_ones(word v)
{
unsigned result = 0;
for (; v > 0; v >>= 1) {
if (v & 1) result++;
}
return result;
}
unsigned GC_n_set_marks(const hdr *hhdr)
{
unsigned result = 0;
size_t i;
# ifdef MARK_BIT_PER_OBJ
size_t n_objs = HBLK_OBJS(hhdr -> hb_sz);
size_t n_mark_words
= divWORDSZ(n_objs > 0 ? n_objs : 1); /* round down */
for (i = 0; i <= n_mark_words; i++) {
result += count_ones(hhdr -> hb_marks[i]);
}
# else
for (i = 0; i < HB_MARKS_SZ; i++) {
result += count_ones(hhdr -> hb_marks[i]);
}
# endif
GC_ASSERT(result > 0);
result--; /* exclude the one bit set past the end */
# ifndef MARK_BIT_PER_OBJ
if (IS_UNCOLLECTABLE(hhdr -> hb_obj_kind)) {
size_t lg = BYTES_TO_GRANULES(hhdr -> hb_sz);
/* As mentioned in GC_set_hdr_marks(), all the bits are set */
/* instead of every n-th, thus the result should be adjusted. */
GC_ASSERT((unsigned)lg != 0 && result % lg == 0);
result /= (unsigned)lg;
}
# endif
return result;
}
# endif /* !USE_MARK_BYTES */
GC_API unsigned GC_CALL GC_count_set_marks_in_hblk(const void *p) {
return GC_n_set_marks(HDR(p));
}
STATIC void GC_CALLBACK GC_print_block_descr(struct hblk *h, void *raw_ps)
{
const hdr *hhdr = HDR(h);
size_t sz = hhdr -> hb_sz;
struct Print_stats *ps = (struct Print_stats *)raw_ps;
size_t n_marks = (size_t)GC_n_set_marks(hhdr);
size_t n_objs = HBLK_OBJS(sz);
# ifndef PARALLEL_MARK
GC_ASSERT(hhdr -> hb_n_marks == n_marks);
# endif
# if defined(CPPCHECK)
GC_noop1_ptr(h);
# endif
GC_ASSERT((n_objs > 0 ? n_objs : 1) >= n_marks);
GC_printf("%u,%u,%u,%u\n", hhdr -> hb_obj_kind, (unsigned)sz,
(unsigned)n_marks, (unsigned)n_objs);
ps -> number_of_blocks++;
ps -> total_bytes += (sz + HBLKSIZE-1) & ~(HBLKSIZE-1); /* round up */
}
void GC_print_block_list(void)
{
struct Print_stats pstats;
GC_printf("kind(0=ptrfree/1=normal/2=unc.),"
"obj_sz,#marks_set,#objs_in_block\n");
BZERO(&pstats, sizeof(pstats));
GC_apply_to_all_blocks(GC_print_block_descr, &pstats);
GC_printf("blocks= %lu, total_bytes= %lu\n",
(unsigned long)pstats.number_of_blocks,
(unsigned long)pstats.total_bytes);
if (pstats.total_bytes + GC_large_free_bytes != GC_heapsize)
GC_err_printf("LOST SOME BLOCKS!! Total bytes should be: %lu\n",
(unsigned long)(GC_heapsize - GC_large_free_bytes));
}
GC_API void GC_CALL GC_print_free_list(int k, size_t lg)
{
void *flh_next;
int n;
GC_ASSERT(k < MAXOBJKINDS);
GC_ASSERT(lg <= MAXOBJGRANULES);
flh_next = GC_obj_kinds[k].ok_freelist[lg];
for (n = 0; flh_next != NULL; n++) {
GC_printf("Free object in heap block %p [%d]: %p\n",
(void *)HBLKPTR(flh_next), n, flh_next);
flh_next = obj_link(flh_next);
}
}
#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.
*/
STATIC void GC_clear_fl_links(void **flp)
{
void *next;
for (next = *flp; next != NULL; next = *flp) {
*flp = NULL;
flp = &obj_link(next);
}
}
/*
* Perform GC_reclaim_block on the entire heap, after first clearing
* small-object free lists (if we are not just looking for leaks).
*/
GC_INNER void GC_start_reclaim(GC_bool report_if_found)
{
int k;
GC_ASSERT(I_HOLD_LOCK());
# if defined(PARALLEL_MARK)
GC_ASSERT(0 == GC_fl_builder_count);
# endif
/* Reset in use counters. GC_reclaim_block recomputes them. */
GC_composite_in_use = 0;
GC_atomic_in_use = 0;
/* Clear reclaim- and free-lists. */
for (k = 0; k < (int)GC_n_kinds; k++) {
struct hblk **rlist = GC_obj_kinds[k].ok_reclaim_list;
GC_bool should_clobber = GC_obj_kinds[k].ok_descriptor != 0;
if (NULL == rlist) continue; /* means this object kind is not used */
if (!report_if_found) {
void **fop;
void **lim = &GC_obj_kinds[k].ok_freelist[MAXOBJGRANULES + 1];
for (fop = GC_obj_kinds[k].ok_freelist;
ADDR_LT((ptr_t)fop, (ptr_t)lim); fop++) {
if (*fop != NULL) {
if (should_clobber) {
GC_clear_fl_links(fop);
} else {
*fop = NULL;
}
}
}
} /* otherwise free-list objects are marked, */
/* and it's safe to leave them. */
BZERO(rlist, (MAXOBJGRANULES + 1) * sizeof(void *));
}
/* 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, (void *)(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);
# elif defined(ENABLE_DISCLAIM)
/* However, make sure to clear reclaimable objects of kinds with */
/* unconditional marking enabled before we do any significant */
/* marking work. */
GC_reclaim_unconditionally_marked();
# endif
# if defined(PARALLEL_MARK)
GC_ASSERT(0 == GC_fl_builder_count);
# endif
}
GC_INNER void GC_continue_reclaim(size_t lg, int k)
{
struct hblk *hbp;
struct obj_kind *ok = &GC_obj_kinds[k];
struct hblk **rlh = ok -> ok_reclaim_list;
void **flh;
GC_ASSERT(I_HOLD_LOCK());
if (NULL == rlh)
return; /* No blocks of this kind. */
flh = &(ok -> ok_freelist[lg]);
for (rlh += lg; (hbp = *rlh) != NULL; ) {
const hdr *hhdr = HDR(hbp);
*rlh = hhdr -> hb_next;
GC_reclaim_small_nonempty_block(hbp, hhdr -> hb_sz, FALSE);
if (*flh != NULL)
break; /* the appropriate free list is nonempty */
}
}
/*
* 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_INNER GC_bool GC_reclaim_all(GC_stop_func stop_func, GC_bool ignore_old)
{
size_t lg;
int k;
const hdr * hhdr;
struct hblk * hbp;
struct hblk ** rlp;
struct hblk ** rlh;
# ifndef NO_CLOCK
CLOCK_TYPE start_time = CLOCK_TYPE_INITIALIZER;
if (GC_print_stats == VERBOSE)
GET_TIME(start_time);
# endif
GC_ASSERT(I_HOLD_LOCK());
for (k = 0; k < (int)GC_n_kinds; k++) {
rlp = GC_obj_kinds[k].ok_reclaim_list;
if (rlp == 0) continue;
for (lg = 1; lg <= MAXOBJGRANULES; lg++) {
for (rlh = rlp + lg; (hbp = *rlh) != NULL; ) {
if (stop_func != (GC_stop_func)0 && (*stop_func)()) {
return FALSE;
}
hhdr = HDR(hbp);
*rlh = hhdr -> hb_next;
if (!ignore_old
|| (word)(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, hhdr -> hb_sz, FALSE);
}
}
}
}
# ifndef NO_CLOCK
if (GC_print_stats == VERBOSE) {
CLOCK_TYPE done_time;
GET_TIME(done_time);
GC_verbose_log_printf(
"Disposing of reclaim lists took %lu ms %lu ns\n",
MS_TIME_DIFF(done_time, start_time),
NS_FRAC_TIME_DIFF(done_time, start_time));
}
# endif
return TRUE;
}
#if !defined(EAGER_SWEEP) && defined(ENABLE_DISCLAIM)
/* We do an eager sweep on heap blocks where unconditional marking has */
/* been enabled, so that any reclaimable objects have been reclaimed */
/* before we start marking. This is a simplified GC_reclaim_all */
/* restricted to kinds where ok_mark_unconditionally is true. */
STATIC void GC_reclaim_unconditionally_marked(void)
{
int k;
GC_ASSERT(I_HOLD_LOCK());
for (k = 0; k < (int)GC_n_kinds; k++) {
size_t lg;
struct obj_kind *ok = &GC_obj_kinds[k];
struct hblk **rlp = ok -> ok_reclaim_list;
if (NULL == rlp || !(ok -> ok_mark_unconditionally)) continue;
for (lg = 1; lg <= MAXOBJGRANULES; lg++) {
struct hblk **rlh = rlp + lg;
struct hblk *hbp;
while ((hbp = *rlh) != NULL) {
const hdr *hhdr = HDR(hbp);
*rlh = hhdr -> hb_next;
GC_reclaim_small_nonempty_block(hbp, hhdr -> hb_sz, FALSE);
}
}
}
}
#endif /* !EAGER_SWEEP && ENABLE_DISCLAIM */
struct enumerate_reachable_s {
GC_reachable_object_proc proc;
void *client_data;
};
STATIC void GC_CALLBACK GC_do_enumerate_reachable_objects(struct hblk *hbp,
void *ed_ptr)
{
const hdr *hhdr = HDR(hbp);
ptr_t p, plim;
const struct enumerate_reachable_s *ped
= (struct enumerate_reachable_s *)ed_ptr;
size_t sz = hhdr -> hb_sz;
size_t bit_no;
if (GC_block_empty(hhdr)) return;
p = hbp -> hb_body;
if (sz > MAXOBJBYTES) { /* one big object */
plim = p;
} else {
plim = p + HBLKSIZE - sz;
}
/* Go through all objects in the block. */
for (bit_no = 0; ADDR_GE(plim, p); bit_no += MARK_BIT_OFFSET(sz), p += sz) {
if (mark_bit_from_hdr(hhdr, bit_no)) {
ped -> proc(p, sz, ped -> client_data);
}
}
}
GC_API void GC_CALL GC_enumerate_reachable_objects_inner(
GC_reachable_object_proc proc,
void *client_data)
{
struct enumerate_reachable_s ed;
GC_ASSERT(I_HOLD_READER_LOCK());
ed.proc = proc;
ed.client_data = client_data;
GC_apply_to_all_blocks(GC_do_enumerate_reachable_objects, &ed);
}