Initial revision
This commit is contained in:
Akinori Ito
726
gc/allchblk.c
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726
gc/allchblk.c
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@@ -0,0 +1,726 @@
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/*
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* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
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* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
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* Copyright (c) 1998-1999 by Silicon Graphics. All rights reserved.
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*
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* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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*
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* Permission is hereby granted to use or copy this program
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* for any purpose, provided the above notices are retained on all copies.
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* Permission to modify the code and to distribute modified code is granted,
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* provided the above notices are retained, and a notice that the code was
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* modified is included with the above copyright notice.
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*/
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#define DEBUG
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#undef DEBUG
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#include <stdio.h>
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#include "gc_priv.h"
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/*
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* Free heap blocks are kept on one of several free lists,
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* depending on the size of the block. Each free list is doubly linked.
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* Adjacent free blocks are coalesced.
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*/
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# define MAX_BLACK_LIST_ALLOC (2*HBLKSIZE)
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/* largest block we will allocate starting on a black */
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/* listed block. Must be >= HBLKSIZE. */
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# define UNIQUE_THRESHOLD 32
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/* Sizes up to this many HBLKs each have their own free list */
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# define HUGE_THRESHOLD 256
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/* Sizes of at least this many heap blocks are mapped to a */
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/* single free list. */
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# define FL_COMPRESSION 8
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/* In between sizes map this many distinct sizes to a single */
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/* bin. */
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# define N_HBLK_FLS (HUGE_THRESHOLD - UNIQUE_THRESHOLD)/FL_COMPRESSION \
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+ UNIQUE_THRESHOLD
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struct hblk * GC_hblkfreelist[N_HBLK_FLS+1] = { 0 };
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/* Map a number of blocks to the appropriate large block free list index. */
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int GC_hblk_fl_from_blocks(blocks_needed)
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word blocks_needed;
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{
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if (blocks_needed <= UNIQUE_THRESHOLD) return blocks_needed;
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if (blocks_needed >= HUGE_THRESHOLD) return N_HBLK_FLS;
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return (blocks_needed - UNIQUE_THRESHOLD)/FL_COMPRESSION
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+ UNIQUE_THRESHOLD;
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}
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# define HBLK_IS_FREE(hdr) ((hdr) -> hb_map == GC_invalid_map)
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# define PHDR(hhdr) HDR(hhdr -> hb_prev)
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# define NHDR(hhdr) HDR(hhdr -> hb_next)
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# ifdef USE_MUNMAP
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# define IS_MAPPED(hhdr) (((hhdr) -> hb_flags & WAS_UNMAPPED) == 0)
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# else /* !USE_MMAP */
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# define IS_MAPPED(hhdr) 1
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# endif /* USE_MUNMAP */
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# if !defined(NO_DEBUGGING)
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void GC_print_hblkfreelist()
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{
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struct hblk * h;
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word total_free = 0;
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hdr * hhdr;
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word sz;
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int i;
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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h = GC_hblkfreelist[i];
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if (0 != h) GC_printf1("Free list %ld:\n", (unsigned long)i);
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while (h != 0) {
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hhdr = HDR(h);
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sz = hhdr -> hb_sz;
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GC_printf2("\t0x%lx size %lu ", (unsigned long)h, (unsigned long)sz);
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total_free += sz;
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if (GC_is_black_listed(h, HBLKSIZE) != 0) {
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GC_printf0("start black listed\n");
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} else if (GC_is_black_listed(h, hhdr -> hb_sz) != 0) {
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GC_printf0("partially black listed\n");
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} else {
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GC_printf0("not black listed\n");
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}
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h = hhdr -> hb_next;
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}
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}
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if (total_free != GC_large_free_bytes) {
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GC_printf1("GC_large_free_bytes = %lu (INCONSISTENT!!)\n",
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(unsigned long) GC_large_free_bytes);
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}
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GC_printf1("Total of %lu bytes on free list\n", (unsigned long)total_free);
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}
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/* Return the free list index on which the block described by the header */
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/* appears, or -1 if it appears nowhere. */
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int free_list_index_of(wanted)
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hdr * wanted;
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{
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struct hblk * h;
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hdr * hhdr;
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int i;
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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h = GC_hblkfreelist[i];
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while (h != 0) {
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hhdr = HDR(h);
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if (hhdr == wanted) return i;
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h = hhdr -> hb_next;
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}
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}
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return -1;
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}
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void GC_dump_regions()
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{
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int i;
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ptr_t start, end;
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ptr_t p;
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size_t bytes;
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hdr *hhdr;
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for (i = 0; i < GC_n_heap_sects; ++i) {
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start = GC_heap_sects[i].hs_start;
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bytes = GC_heap_sects[i].hs_bytes;
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end = start + bytes;
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/* Merge in contiguous sections. */
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while (i+1 < GC_n_heap_sects && GC_heap_sects[i+1].hs_start == end) {
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++i;
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end = GC_heap_sects[i].hs_start + GC_heap_sects[i].hs_bytes;
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}
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GC_printf2("***Section from 0x%lx to 0x%lx\n", start, end);
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for (p = start; p < end;) {
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hhdr = HDR(p);
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GC_printf1("\t0x%lx ", (unsigned long)p);
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if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
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GC_printf1("Missing header!!\n", hhdr);
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p += HBLKSIZE;
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continue;
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}
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if (HBLK_IS_FREE(hhdr)) {
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int correct_index = GC_hblk_fl_from_blocks(
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divHBLKSZ(hhdr -> hb_sz));
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int actual_index;
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GC_printf1("\tfree block of size 0x%lx bytes",
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(unsigned long)(hhdr -> hb_sz));
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if (IS_MAPPED(hhdr)) {
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GC_printf0("\n");
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} else {
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GC_printf0("(unmapped)\n");
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}
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actual_index = free_list_index_of(hhdr);
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if (-1 == actual_index) {
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GC_printf1("\t\tBlock not on free list %ld!!\n",
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correct_index);
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} else if (correct_index != actual_index) {
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GC_printf2("\t\tBlock on list %ld, should be on %ld!!\n",
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actual_index, correct_index);
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}
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p += hhdr -> hb_sz;
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} else {
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GC_printf1("\tused for blocks of size 0x%lx bytes\n",
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(unsigned long)WORDS_TO_BYTES(hhdr -> hb_sz));
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p += HBLKSIZE * OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
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}
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}
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}
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}
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# endif /* NO_DEBUGGING */
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/* Initialize hdr for a block containing the indicated size and */
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/* kind of objects. */
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/* Return FALSE on failure. */
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static GC_bool setup_header(hhdr, sz, kind, flags)
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register hdr * hhdr;
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word sz; /* object size in words */
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int kind;
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unsigned char flags;
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{
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register word descr;
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/* Add description of valid object pointers */
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if (!GC_add_map_entry(sz)) return(FALSE);
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hhdr -> hb_map = GC_obj_map[sz > MAXOBJSZ? 0 : sz];
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/* Set size, kind and mark proc fields */
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hhdr -> hb_sz = sz;
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hhdr -> hb_obj_kind = kind;
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hhdr -> hb_flags = flags;
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descr = GC_obj_kinds[kind].ok_descriptor;
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if (GC_obj_kinds[kind].ok_relocate_descr) descr += WORDS_TO_BYTES(sz);
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hhdr -> hb_descr = descr;
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/* Clear mark bits */
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GC_clear_hdr_marks(hhdr);
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hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
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return(TRUE);
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}
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#define FL_UNKNOWN -1
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/*
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* Remove hhdr from the appropriate free list.
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* We assume it is on the nth free list, or on the size
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* appropriate free list if n is FL_UNKNOWN.
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*/
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void GC_remove_from_fl(hhdr, n)
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hdr * hhdr;
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int n;
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{
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GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0);
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if (hhdr -> hb_prev == 0) {
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int index;
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if (FL_UNKNOWN == n) {
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index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
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} else {
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index = n;
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}
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GC_ASSERT(HDR(GC_hblkfreelist[index]) == hhdr);
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GC_hblkfreelist[index] = hhdr -> hb_next;
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} else {
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PHDR(hhdr) -> hb_next = hhdr -> hb_next;
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}
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if (0 != hhdr -> hb_next) {
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GC_ASSERT(!IS_FORWARDING_ADDR_OR_NIL(NHDR(hhdr)));
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NHDR(hhdr) -> hb_prev = hhdr -> hb_prev;
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}
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}
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/*
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* Return a pointer to the free block ending just before h, if any.
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*/
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struct hblk * GC_free_block_ending_at(h)
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struct hblk *h;
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{
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struct hblk * p = h - 1;
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hdr * phdr = HDR(p);
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while (0 != phdr && IS_FORWARDING_ADDR_OR_NIL(phdr)) {
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p = FORWARDED_ADDR(p,phdr);
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phdr = HDR(p);
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}
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if (0 != phdr && HBLK_IS_FREE(phdr)) return p;
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p = GC_prev_block(h - 1);
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if (0 != p) {
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phdr = HDR(p);
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if (HBLK_IS_FREE(phdr) && (ptr_t)p + phdr -> hb_sz == (ptr_t)h) {
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return p;
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}
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}
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return 0;
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}
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/*
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* Add hhdr to the appropriate free list.
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* We maintain individual free lists sorted by address.
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*/
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void GC_add_to_fl(h, hhdr)
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struct hblk *h;
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hdr * hhdr;
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{
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int index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
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struct hblk *second = GC_hblkfreelist[index];
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# ifdef GC_ASSERTIONS
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struct hblk *next = (struct hblk *)((word)h + hhdr -> hb_sz);
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hdr * nexthdr = HDR(next);
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struct hblk *prev = GC_free_block_ending_at(h);
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hdr * prevhdr = HDR(prev);
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GC_ASSERT(nexthdr == 0 || !HBLK_IS_FREE(nexthdr) || !IS_MAPPED(nexthdr));
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GC_ASSERT(prev == 0 || !HBLK_IS_FREE(prevhdr) || !IS_MAPPED(prevhdr));
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# endif
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GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0);
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GC_hblkfreelist[index] = h;
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hhdr -> hb_next = second;
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hhdr -> hb_prev = 0;
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if (0 != second) HDR(second) -> hb_prev = h;
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GC_invalidate_map(hhdr);
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}
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#ifdef USE_MUNMAP
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/* Unmap blocks that haven't been recently touched. This is the only way */
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/* way blocks are ever unmapped. */
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void GC_unmap_old(void)
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{
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struct hblk * h;
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hdr * hhdr;
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word sz;
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unsigned short last_rec, threshold;
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int i;
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# define UNMAP_THRESHOLD 6
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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for (h = GC_hblkfreelist[i]; 0 != h; h = hhdr -> hb_next) {
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hhdr = HDR(h);
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if (!IS_MAPPED(hhdr)) continue;
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threshold = (unsigned short)(GC_gc_no - UNMAP_THRESHOLD);
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last_rec = hhdr -> hb_last_reclaimed;
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if (last_rec > GC_gc_no
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|| last_rec < threshold && threshold < GC_gc_no
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/* not recently wrapped */) {
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sz = hhdr -> hb_sz;
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GC_unmap((ptr_t)h, sz);
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hhdr -> hb_flags |= WAS_UNMAPPED;
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}
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}
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}
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}
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/* Merge all unmapped blocks that are adjacent to other free */
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/* blocks. This may involve remapping, since all blocks are either */
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/* fully mapped or fully unmapped. */
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void GC_merge_unmapped(void)
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{
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struct hblk * h, *next;
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hdr * hhdr, *nexthdr;
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word size, nextsize;
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int i;
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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h = GC_hblkfreelist[i];
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while (h != 0) {
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hhdr = HDR(h);
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size = hhdr->hb_sz;
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next = (struct hblk *)((word)h + size);
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nexthdr = HDR(next);
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/* Coalesce with successor, if possible */
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if (0 != nexthdr && HBLK_IS_FREE(nexthdr)) {
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nextsize = nexthdr -> hb_sz;
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if (IS_MAPPED(hhdr)) {
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GC_ASSERT(!IS_MAPPED(nexthdr));
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/* make both consistent, so that we can merge */
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if (size > nextsize) {
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GC_remap((ptr_t)next, nextsize);
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} else {
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GC_unmap((ptr_t)h, size);
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hhdr -> hb_flags |= WAS_UNMAPPED;
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}
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} else if (IS_MAPPED(nexthdr)) {
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GC_ASSERT(!IS_MAPPED(hhdr));
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if (size > nextsize) {
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GC_unmap((ptr_t)next, nextsize);
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} else {
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GC_remap((ptr_t)h, size);
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hhdr -> hb_flags &= ~WAS_UNMAPPED;
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}
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} else {
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/* Unmap any gap in the middle */
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GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nexthdr -> hb_sz);
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}
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/* If they are both unmapped, we merge, but leave unmapped. */
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GC_remove_from_fl(hhdr, i);
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GC_remove_from_fl(nexthdr, FL_UNKNOWN);
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hhdr -> hb_sz += nexthdr -> hb_sz;
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GC_remove_header(next);
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GC_add_to_fl(h, hhdr);
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/* Start over at beginning of list */
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h = GC_hblkfreelist[i];
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} else /* not mergable with successor */ {
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h = hhdr -> hb_next;
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}
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} /* while (h != 0) ... */
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} /* for ... */
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}
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#endif /* USE_MUNMAP */
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/*
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* Return a pointer to a block starting at h of length bytes.
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* Memory for the block is mapped.
|
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* Remove the block from its free list, and return the remainder (if any)
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* to its appropriate free list.
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* May fail by returning 0.
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* The header for the returned block must be set up by the caller.
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* If the return value is not 0, then hhdr is the header for it.
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*/
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struct hblk * GC_get_first_part(h, hhdr, bytes, index)
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struct hblk *h;
|
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hdr * hhdr;
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word bytes;
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int index;
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{
|
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word total_size = hhdr -> hb_sz;
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struct hblk * rest;
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hdr * rest_hdr;
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GC_ASSERT((total_size & (HBLKSIZE-1)) == 0);
|
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GC_remove_from_fl(hhdr, index);
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if (total_size == bytes) return h;
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rest = (struct hblk *)((word)h + bytes);
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if (!GC_install_header(rest)) return(0);
|
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rest_hdr = HDR(rest);
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rest_hdr -> hb_sz = total_size - bytes;
|
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rest_hdr -> hb_flags = 0;
|
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# ifdef GC_ASSERTIONS
|
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// Mark h not free, to avoid assertion about adjacent free blocks.
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hhdr -> hb_map = 0;
|
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# endif
|
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GC_add_to_fl(rest, rest_hdr);
|
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return h;
|
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}
|
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|
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/*
|
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* H is a free block. N points at an address inside it.
|
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* A new header for n has already been set up. Fix up h's header
|
||||
* to reflect the fact that it is being split, move it to the
|
||||
* appropriate free list.
|
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* N replaces h in the original free list.
|
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*
|
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* Nhdr is not completely filled in, since it is about to allocated.
|
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* It may in fact end up on the wrong free list for its size.
|
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* (Hence adding it to a free list is silly. But this path is hopefully
|
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* rare enough that it doesn't matter. The code is cleaner this way.)
|
||||
*/
|
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void GC_split_block(h, hhdr, n, nhdr, index)
|
||||
struct hblk *h;
|
||||
hdr * hhdr;
|
||||
struct hblk *n;
|
||||
hdr * nhdr;
|
||||
int index; /* Index of free list */
|
||||
{
|
||||
word total_size = hhdr -> hb_sz;
|
||||
word h_size = (word)n - (word)h;
|
||||
struct hblk *prev = hhdr -> hb_prev;
|
||||
struct hblk *next = hhdr -> hb_next;
|
||||
|
||||
/* Replace h with n on its freelist */
|
||||
nhdr -> hb_prev = prev;
|
||||
nhdr -> hb_next = next;
|
||||
nhdr -> hb_sz = total_size - h_size;
|
||||
nhdr -> hb_flags = 0;
|
||||
if (0 != prev) {
|
||||
HDR(prev) -> hb_next = n;
|
||||
} else {
|
||||
GC_hblkfreelist[index] = n;
|
||||
}
|
||||
if (0 != next) {
|
||||
HDR(next) -> hb_prev = n;
|
||||
}
|
||||
# ifdef GC_ASSERTIONS
|
||||
nhdr -> hb_map = 0; /* Don't fail test for consecutive */
|
||||
/* free blocks in GC_add_to_fl. */
|
||||
# endif
|
||||
# ifdef USE_MUNMAP
|
||||
hhdr -> hb_last_reclaimed = GC_gc_no;
|
||||
# endif
|
||||
hhdr -> hb_sz = h_size;
|
||||
GC_add_to_fl(h, hhdr);
|
||||
GC_invalidate_map(nhdr);
|
||||
}
|
||||
|
||||
struct hblk * GC_allochblk_nth();
|
||||
|
||||
/*
|
||||
* Allocate (and return pointer to) a heap block
|
||||
* for objects of size sz words, searching the nth free list.
|
||||
*
|
||||
* NOTE: We set obj_map field in header correctly.
|
||||
* Caller is responsible for building an object freelist in block.
|
||||
*
|
||||
* We clear the block if it is destined for large objects, and if
|
||||
* kind requires that newly allocated objects be cleared.
|
||||
*/
|
||||
struct hblk *
|
||||
GC_allochblk(sz, kind, flags)
|
||||
word sz;
|
||||
int kind;
|
||||
unsigned char flags; /* IGNORE_OFF_PAGE or 0 */
|
||||
{
|
||||
int start_list = GC_hblk_fl_from_blocks(OBJ_SZ_TO_BLOCKS(sz));
|
||||
int i;
|
||||
for (i = start_list; i <= N_HBLK_FLS; ++i) {
|
||||
struct hblk * result = GC_allochblk_nth(sz, kind, flags, i);
|
||||
if (0 != result) return result;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
/*
|
||||
* The same, but with search restricted to nth free list.
|
||||
*/
|
||||
struct hblk *
|
||||
GC_allochblk_nth(sz, kind, flags, n)
|
||||
word sz;
|
||||
int kind;
|
||||
unsigned char flags; /* IGNORE_OFF_PAGE or 0 */
|
||||
int n;
|
||||
{
|
||||
register struct hblk *hbp;
|
||||
register hdr * hhdr; /* Header corr. to hbp */
|
||||
register struct hblk *thishbp;
|
||||
register hdr * thishdr; /* Header corr. to hbp */
|
||||
signed_word size_needed; /* number of bytes in requested objects */
|
||||
signed_word size_avail; /* bytes available in this block */
|
||||
|
||||
size_needed = HBLKSIZE * OBJ_SZ_TO_BLOCKS(sz);
|
||||
|
||||
/* search for a big enough block in free list */
|
||||
hbp = GC_hblkfreelist[n];
|
||||
hhdr = HDR(hbp);
|
||||
for(; 0 != hbp; hbp = hhdr -> hb_next, hhdr = HDR(hbp)) {
|
||||
size_avail = hhdr->hb_sz;
|
||||
if (size_avail < size_needed) continue;
|
||||
# ifdef PRESERVE_LAST
|
||||
if (size_avail != size_needed
|
||||
&& !GC_incremental && GC_should_collect()) {
|
||||
continue;
|
||||
}
|
||||
# endif
|
||||
/* If the next heap block is obviously better, go on. */
|
||||
/* This prevents us from disassembling a single large block */
|
||||
/* to get tiny blocks. */
|
||||
{
|
||||
signed_word next_size;
|
||||
|
||||
thishbp = hhdr -> hb_next;
|
||||
if (thishbp != 0) {
|
||||
thishdr = HDR(thishbp);
|
||||
next_size = (signed_word)(thishdr -> hb_sz);
|
||||
if (next_size < size_avail
|
||||
&& next_size >= size_needed
|
||||
&& !GC_is_black_listed(thishbp, (word)size_needed)) {
|
||||
continue;
|
||||
}
|
||||
}
|
||||
}
|
||||
if ( !IS_UNCOLLECTABLE(kind) &&
|
||||
(kind != PTRFREE || size_needed > MAX_BLACK_LIST_ALLOC)) {
|
||||
struct hblk * lasthbp = hbp;
|
||||
ptr_t search_end = (ptr_t)hbp + size_avail - size_needed;
|
||||
signed_word orig_avail = size_avail;
|
||||
signed_word eff_size_needed = ((flags & IGNORE_OFF_PAGE)?
|
||||
HBLKSIZE
|
||||
: size_needed);
|
||||
|
||||
|
||||
while ((ptr_t)lasthbp <= search_end
|
||||
&& (thishbp = GC_is_black_listed(lasthbp,
|
||||
(word)eff_size_needed))) {
|
||||
lasthbp = thishbp;
|
||||
}
|
||||
size_avail -= (ptr_t)lasthbp - (ptr_t)hbp;
|
||||
thishbp = lasthbp;
|
||||
if (size_avail >= size_needed) {
|
||||
if (thishbp != hbp && GC_install_header(thishbp)) {
|
||||
/* Make sure it's mapped before we mangle it. */
|
||||
# ifdef USE_MUNMAP
|
||||
if (!IS_MAPPED(hhdr)) {
|
||||
GC_remap((ptr_t)hbp, size_avail);
|
||||
hhdr -> hb_flags &= ~WAS_UNMAPPED;
|
||||
}
|
||||
# endif
|
||||
/* Split the block at thishbp */
|
||||
thishdr = HDR(thishbp);
|
||||
GC_split_block(hbp, hhdr, thishbp, thishdr, n);
|
||||
/* Advance to thishbp */
|
||||
hbp = thishbp;
|
||||
hhdr = thishdr;
|
||||
/* We must now allocate thishbp, since it may */
|
||||
/* be on the wrong free list. */
|
||||
}
|
||||
} else if (size_needed > (signed_word)BL_LIMIT
|
||||
&& orig_avail - size_needed
|
||||
> (signed_word)BL_LIMIT) {
|
||||
/* Punt, since anything else risks unreasonable heap growth. */
|
||||
WARN("Needed to allocate blacklisted block at 0x%lx\n",
|
||||
(word)hbp);
|
||||
size_avail = orig_avail;
|
||||
} else if (size_avail == 0 && size_needed == HBLKSIZE
|
||||
&& IS_MAPPED(hhdr)) {
|
||||
if (!GC_find_leak) {
|
||||
static unsigned count = 0;
|
||||
|
||||
/* The block is completely blacklisted. We need */
|
||||
/* to drop some such blocks, since otherwise we spend */
|
||||
/* all our time traversing them if pointerfree */
|
||||
/* blocks are unpopular. */
|
||||
/* A dropped block will be reconsidered at next GC. */
|
||||
if ((++count & 3) == 0) {
|
||||
/* Allocate and drop the block in small chunks, to */
|
||||
/* maximize the chance that we will recover some */
|
||||
/* later. */
|
||||
word total_size = hhdr -> hb_sz;
|
||||
struct hblk * limit = hbp + divHBLKSZ(total_size);
|
||||
struct hblk * h;
|
||||
struct hblk * prev = hhdr -> hb_prev;
|
||||
|
||||
GC_words_wasted += total_size;
|
||||
GC_large_free_bytes -= total_size;
|
||||
GC_remove_from_fl(hhdr, n);
|
||||
for (h = hbp; h < limit; h++) {
|
||||
if (h == hbp || GC_install_header(h)) {
|
||||
hhdr = HDR(h);
|
||||
(void) setup_header(
|
||||
hhdr,
|
||||
BYTES_TO_WORDS(HBLKSIZE - HDR_BYTES),
|
||||
PTRFREE, 0); /* Cant fail */
|
||||
if (GC_debugging_started) {
|
||||
BZERO(h + HDR_BYTES, HBLKSIZE - HDR_BYTES);
|
||||
}
|
||||
}
|
||||
}
|
||||
/* Restore hbp to point at free block */
|
||||
hbp = prev;
|
||||
if (0 == hbp) {
|
||||
return GC_allochblk_nth(sz, kind, flags, n);
|
||||
}
|
||||
hhdr = HDR(hbp);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
if( size_avail >= size_needed ) {
|
||||
# ifdef USE_MUNMAP
|
||||
if (!IS_MAPPED(hhdr)) {
|
||||
GC_remap((ptr_t)hbp, size_avail);
|
||||
hhdr -> hb_flags &= ~WAS_UNMAPPED;
|
||||
}
|
||||
# endif
|
||||
/* hbp may be on the wrong freelist; the parameter n */
|
||||
/* is important. */
|
||||
hbp = GC_get_first_part(hbp, hhdr, size_needed, n);
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
if (0 == hbp) return 0;
|
||||
|
||||
/* Notify virtual dirty bit implementation that we are about to write. */
|
||||
GC_write_hint(hbp);
|
||||
|
||||
/* Add it to map of valid blocks */
|
||||
if (!GC_install_counts(hbp, (word)size_needed)) return(0);
|
||||
/* This leaks memory under very rare conditions. */
|
||||
|
||||
/* Set up header */
|
||||
if (!setup_header(hhdr, sz, kind, flags)) {
|
||||
GC_remove_counts(hbp, (word)size_needed);
|
||||
return(0); /* ditto */
|
||||
}
|
||||
|
||||
/* Clear block if necessary */
|
||||
if (GC_debugging_started
|
||||
|| sz > MAXOBJSZ && GC_obj_kinds[kind].ok_init) {
|
||||
BZERO(hbp + HDR_BYTES, size_needed - HDR_BYTES);
|
||||
}
|
||||
|
||||
/* We just successfully allocated a block. Restart count of */
|
||||
/* consecutive failures. */
|
||||
{
|
||||
extern unsigned GC_fail_count;
|
||||
|
||||
GC_fail_count = 0;
|
||||
}
|
||||
|
||||
GC_large_free_bytes -= size_needed;
|
||||
|
||||
GC_ASSERT(IS_MAPPED(hhdr));
|
||||
return( hbp );
|
||||
}
|
||||
|
||||
struct hblk * GC_freehblk_ptr = 0; /* Search position hint for GC_freehblk */
|
||||
|
||||
/*
|
||||
* Free a heap block.
|
||||
*
|
||||
* Coalesce the block with its neighbors if possible.
|
||||
*
|
||||
* All mark words are assumed to be cleared.
|
||||
*/
|
||||
void
|
||||
GC_freehblk(hbp)
|
||||
struct hblk *hbp;
|
||||
{
|
||||
struct hblk *next, *prev;
|
||||
hdr *hhdr, *prevhdr, *nexthdr;
|
||||
signed_word size;
|
||||
|
||||
|
||||
hhdr = HDR(hbp);
|
||||
size = hhdr->hb_sz;
|
||||
size = HBLKSIZE * OBJ_SZ_TO_BLOCKS(size);
|
||||
GC_remove_counts(hbp, (word)size);
|
||||
hhdr->hb_sz = size;
|
||||
|
||||
/* Check for duplicate deallocation in the easy case */
|
||||
if (HBLK_IS_FREE(hhdr)) {
|
||||
GC_printf1("Duplicate large block deallocation of 0x%lx\n",
|
||||
(unsigned long) hbp);
|
||||
}
|
||||
|
||||
GC_ASSERT(IS_MAPPED(hhdr));
|
||||
GC_invalidate_map(hhdr);
|
||||
next = (struct hblk *)((word)hbp + size);
|
||||
nexthdr = HDR(next);
|
||||
prev = GC_free_block_ending_at(hbp);
|
||||
/* Coalesce with successor, if possible */
|
||||
if(0 != nexthdr && HBLK_IS_FREE(nexthdr) && IS_MAPPED(nexthdr)) {
|
||||
GC_remove_from_fl(nexthdr, FL_UNKNOWN);
|
||||
hhdr -> hb_sz += nexthdr -> hb_sz;
|
||||
GC_remove_header(next);
|
||||
}
|
||||
/* Coalesce with predecessor, if possible. */
|
||||
if (0 != prev) {
|
||||
prevhdr = HDR(prev);
|
||||
if (IS_MAPPED(prevhdr)) {
|
||||
GC_remove_from_fl(prevhdr, FL_UNKNOWN);
|
||||
prevhdr -> hb_sz += hhdr -> hb_sz;
|
||||
GC_remove_header(hbp);
|
||||
hbp = prev;
|
||||
hhdr = prevhdr;
|
||||
}
|
||||
}
|
||||
|
||||
GC_large_free_bytes += size;
|
||||
GC_add_to_fl(hbp, hhdr);
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user