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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.
*
* 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"
#include <stdio.h>
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 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. */
#ifndef MAX_LEAKED
# define MAX_LEAKED 40
#endif
STATIC ptr_t GC_leaked[MAX_LEAKED] = { NULL };
STATIC unsigned GC_n_leaked = 0;
GC_INNER GC_bool GC_have_errors = FALSE;
GC_INLINE void GC_add_leaked(ptr_t leaked)
{
# ifndef SHORT_DBG_HDRS
if (GC_findleak_delay_free && !GC_check_leaked(leaked))
return;
# endif
GC_have_errors = TRUE;
/* FIXME: Prevent adding an object while printing leaked ones. */
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 allocation lock held. */
GC_INNER void GC_print_all_errors(void)
{
static GC_bool printing_errors = FALSE;
GC_bool have_errors;
unsigned i;
DCL_LOCK_STATE;
LOCK();
if (printing_errors) {
UNLOCK();
return;
}
have_errors = GC_have_errors;
printing_errors = TRUE;
UNLOCK();
if (GC_debugging_started) {
GC_print_all_smashed();
} else {
have_errors = FALSE;
}
for (i = 0; i < GC_n_leaked; ++i) {
ptr_t p = GC_leaked[i];
if (HDR(p) -> hb_obj_kind == PTRFREE) {
GC_err_printf("Leaked atomic object at ");
} else {
GC_err_printf("Leaked composite object at ");
}
GC_print_heap_obj(p);
GC_err_printf("\n");
GC_free(p);
GC_leaked[i] = 0;
have_errors = TRUE;
}
GC_n_leaked = 0;
if (have_errors
# ifndef GC_ABORT_ON_LEAK
&& GETENV("GC_ABORT_ON_LEAK") != NULL
# endif
) {
ABORT("Leaked or smashed objects encountered");
}
printing_errors = FALSE;
}
/*
* 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(hdr *hhdr)
{
return (hhdr -> hb_n_marks == 0);
}
STATIC GC_bool GC_block_nearly_full(hdr *hhdr)
{
return (hhdr -> hb_n_marks > 7 * HBLK_OBJS(hhdr -> hb_sz)/8);
}
/* FIXME: This should perhaps again be specialized for USE_MARK_BYTES */
/* and USE_MARK_BITS cases. */
/*
* 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, hdr *hhdr, size_t sz,
ptr_t list, signed_word *count)
{
word bit_no = 0;
word *p, *q, *plim;
signed_word n_bytes_found = 0;
GC_ASSERT(hhdr == GC_find_header((ptr_t)hbp));
GC_ASSERT(sz == hhdr -> hb_sz);
GC_ASSERT((sz & (BYTES_PER_WORD-1)) == 0);
p = (word *)(hbp->hb_body);
plim = (word *)(hbp->hb_body + HBLKSIZE - sz);
/* go through all words in block */
while (p <= plim) {
if( mark_bit_from_hdr(hhdr, bit_no) ) {
p = (word *)((ptr_t)p + sz);
} else {
n_bytes_found += 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 = (word *)((ptr_t)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
}
bit_no += MARK_BIT_OFFSET(sz);
}
*count += n_bytes_found;
return(list);
}
/* The same thing, but don't clear objects: */
STATIC ptr_t GC_reclaim_uninit(struct hblk *hbp, hdr *hhdr, size_t sz,
ptr_t list, signed_word *count)
{
word bit_no = 0;
word *p, *plim;
signed_word n_bytes_found = 0;
GC_ASSERT(sz == hhdr -> hb_sz);
p = (word *)(hbp->hb_body);
plim = (word *)((ptr_t)hbp + HBLKSIZE - sz);
/* go through all words in block */
while (p <= plim) {
if( !mark_bit_from_hdr(hhdr, bit_no) ) {
n_bytes_found += sz;
/* object is available - put on list */
obj_link(p) = list;
list = ((ptr_t)p);
}
p = (word *)((ptr_t)p + sz);
bit_no += MARK_BIT_OFFSET(sz);
}
*count += n_bytes_found;
return(list);
}
/* Don't really reclaim objects, just check for unmarked ones: */
STATIC void GC_reclaim_check(struct hblk *hbp, hdr *hhdr, word sz)
{
word bit_no;
ptr_t p, plim;
GC_ASSERT(sz == hhdr -> hb_sz);
/* go through all words in block */
p = hbp->hb_body;
plim = p + HBLKSIZE - sz;
for (bit_no = 0; p <= plim; p += sz, bit_no += MARK_BIT_OFFSET(sz)) {
if (!mark_bit_from_hdr(hhdr, bit_no)) {
GC_add_leaked(p);
}
}
}
/*
* Generic procedure to rebuild a free list in hbp.
* Also called directly from GC_malloc_many.
* Sz is now in bytes.
*/
GC_INNER ptr_t GC_reclaim_generic(struct hblk * hbp, hdr *hhdr, size_t sz,
GC_bool init, ptr_t list,
signed_word *count)
{
ptr_t result;
GC_ASSERT(GC_find_header((ptr_t)hbp) == hhdr);
# ifndef GC_DISABLE_INCREMENTAL
GC_remove_protection(hbp, 1, (hhdr)->hb_descr == 0 /* Pointer-free? */);
# endif
if (init || GC_debugging_started) {
result = GC_reclaim_clear(hbp, hhdr, sz, list, count);
} else {
GC_ASSERT((hhdr)->hb_descr == 0 /* Pointer-free block */);
result = GC_reclaim_uninit(hbp, hhdr, sz, list, count);
}
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,
GC_bool report_if_found)
{
hdr *hhdr = HDR(hbp);
size_t sz = hhdr -> hb_sz;
struct obj_kind * ok = &GC_obj_kinds[hhdr -> hb_obj_kind];
void **flh = &(ok -> ok_freelist[BYTES_TO_GRANULES(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,
*flh, &GC_bytes_found);
}
}
/*
* 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_reclaim_block(struct hblk *hbp, word report_if_found)
{
hdr * hhdr = HDR(hbp);
size_t sz = hhdr -> hb_sz; /* size of objects in current block */
struct obj_kind * ok = &GC_obj_kinds[hhdr -> hb_obj_kind];
struct hblk ** rlh;
if( sz > MAXOBJBYTES ) { /* 1 big object */
if( !mark_bit_from_hdr(hhdr, 0) ) {
if (report_if_found) {
GC_add_leaked((ptr_t)hbp);
} else {
size_t blocks = OBJ_SZ_TO_BLOCKS(sz);
if (blocks > 1) {
GC_large_allocd_bytes -= blocks * HBLKSIZE;
}
GC_bytes_found += sz;
GC_freehblk(hbp);
}
} else {
if (hhdr -> hb_descr != 0) {
GC_composite_in_use += sz;
} else {
GC_atomic_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 two markers, but this is extremely */
/* unlikely to fail spuriously with more. And if it does, it */
/* should be looked at. */
GC_ASSERT(hhdr -> hb_n_marks <= 2 * (HBLKSIZE/sz + 1) + 16);
# else
GC_ASSERT(sz * hhdr -> hb_n_marks <= HBLKSIZE);
# endif
if (hhdr -> hb_descr != 0) {
GC_composite_in_use += sz * hhdr -> hb_n_marks;
} else {
GC_atomic_in_use += sz * hhdr -> hb_n_marks;
}
if (report_if_found) {
GC_reclaim_small_nonempty_block(hbp, TRUE /* report_if_found */);
} else if (empty) {
GC_bytes_found += HBLKSIZE;
GC_freehblk(hbp);
} else if (GC_find_leak || !GC_block_nearly_full(hhdr)) {
/* group of smaller objects, enqueue the real work */
rlh = &(ok -> ok_reclaim_list[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 !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 */
STATIC int GC_n_set_marks(hdr *hhdr)
{
int result = 0;
int i;
size_t sz = hhdr -> hb_sz;
int offset = (int)MARK_BIT_OFFSET(sz);
int limit = (int)FINAL_MARK_BIT(sz);
for (i = 0; i < limit; i += offset) {
result += hhdr -> hb_marks[i];
}
GC_ASSERT(hhdr -> hb_marks[limit]);
return(result);
}
#else
/* Number of set bits in a word. Not performance critical. */
static int set_bits(word n)
{
word m = n;
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 */
STATIC int GC_n_set_marks(hdr *hhdr)
{
int result = 0;
int i;
int n_mark_words;
# ifdef MARK_BIT_PER_OBJ
int n_objs = (int)HBLK_OBJS(hhdr -> hb_sz);
if (0 == n_objs) n_objs = 1;
n_mark_words = divWORDSZ(n_objs + WORDSZ - 1);
# else /* MARK_BIT_PER_GRANULE */
n_mark_words = MARK_BITS_SZ;
# endif
for (i = 0; i < n_mark_words - 1; i++) {
result += set_bits(hhdr -> hb_marks[i]);
}
# ifdef MARK_BIT_PER_OBJ
result += set_bits((hhdr -> hb_marks[n_mark_words - 1])
<< (n_mark_words * WORDSZ - n_objs));
# else
result += set_bits(hhdr -> hb_marks[n_mark_words - 1]);
# endif
return(result - 1);
}
#endif /* !USE_MARK_BYTES */
STATIC void GC_print_block_descr(struct hblk *h,
word /* struct PrintStats */ raw_ps)
{
hdr * hhdr = HDR(h);
size_t bytes = hhdr -> hb_sz;
struct Print_stats *ps;
unsigned n_marks = GC_n_set_marks(hhdr);
if (hhdr -> hb_n_marks != n_marks) {
GC_printf("(%u:%u,%u!=%u)", hhdr -> hb_obj_kind, (unsigned)bytes,
(unsigned)hhdr -> hb_n_marks, n_marks);
} else {
GC_printf("(%u:%u,%u)", hhdr -> hb_obj_kind,
(unsigned)bytes, n_marks);
}
bytes += HBLKSIZE-1;
bytes &= ~(HBLKSIZE-1);
ps = (struct Print_stats *)raw_ps;
ps->total_bytes += bytes;
ps->number_of_blocks++;
}
void GC_print_block_list(void)
{
struct Print_stats pstats;
GC_printf("(kind(0=ptrfree,1=normal,2=unc.):size_in_bytes, #_marks_set)\n");
pstats.number_of_blocks = 0;
pstats.total_bytes = 0;
GC_apply_to_all_blocks(GC_print_block_descr, (word)&pstats);
GC_printf("\nblocks = %lu, bytes = %lu\n",
(unsigned long)pstats.number_of_blocks,
(unsigned long)pstats.total_bytes);
}
/* Currently for debugger use only: */
void GC_print_free_list(int kind, size_t sz_in_granules)
{
struct obj_kind * ok = &GC_obj_kinds[kind];
ptr_t flh = ok -> ok_freelist[sz_in_granules];
struct hblk *lastBlock = 0;
int n;
for (n = 1; flh; n++) {
struct hblk *block = HBLKPTR(flh);
if (block != lastBlock) {
GC_printf("\nIn heap block at %p:\n\t", block);
lastBlock = block;
}
GC_printf("%d: %p;", n, flh);
flh = obj_link(flh);
}
}
#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 = *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).
*/
GC_INNER void GC_start_reclaim(GC_bool report_if_found)
{
unsigned kind;
# 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 (kind = 0; kind < GC_n_kinds; kind++) {
void **fop;
void **lim;
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[MAXOBJGRANULES+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 */
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, (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)
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.
*/
GC_INNER void GC_continue_reclaim(size_t sz /* granules */, int kind)
{
hdr * hhdr;
struct hblk * hbp;
struct obj_kind * ok = &(GC_obj_kinds[kind]);
struct hblk ** rlh = ok -> ok_reclaim_list;
void **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);
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_INNER GC_bool GC_reclaim_all(GC_stop_func stop_func, GC_bool ignore_old)
{
word sz;
unsigned kind;
hdr * hhdr;
struct hblk * hbp;
struct obj_kind * ok;
struct hblk ** rlp;
struct hblk ** rlh;
# ifndef SMALL_CONFIG
CLOCK_TYPE start_time = 0; /* initialized to prevent warning. */
CLOCK_TYPE done_time;
if (GC_print_stats == VERBOSE)
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 <= MAXOBJGRANULES; 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);
}
}
}
}
# ifndef SMALL_CONFIG
if (GC_print_stats == VERBOSE) {
GET_TIME(done_time);
GC_log_printf("Disposing of reclaim lists took %lu msecs\n",
MS_TIME_DIFF(done_time,start_time));
}
# endif
return(TRUE);
}