924 lines
34 KiB
C
924 lines
34 KiB
C
/*
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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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* Copyright (c) 1999 by Hewlett-Packard Company. 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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#include "private/gc_priv.h"
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#include <stdio.h>
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#ifdef GC_USE_ENTIRE_HEAP
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int GC_use_entire_heap = TRUE;
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#else
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int GC_use_entire_heap = FALSE;
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#endif
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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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#ifndef GC_GCJ_SUPPORT
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STATIC
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#endif
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struct hblk * GC_hblkfreelist[N_HBLK_FLS+1] = { 0 };
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/* List of completely empty heap blocks */
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/* Linked through hb_next field of */
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/* header structure associated with */
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/* block. Remains externally visible */
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/* as used by GNU GCJ currently. */
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#ifndef GC_GCJ_SUPPORT
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STATIC
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#endif
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word GC_free_bytes[N_HBLK_FLS+1] = { 0 };
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/* Number of free bytes on each list. Remains visible to GCJ. */
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/* Return the largest n such that the number of free bytes on lists */
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/* n .. N_HBLK_FLS is greater or equal to GC_max_large_allocd_bytes */
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/* minus GC_large_allocd_bytes. If there is no such n, return 0. */
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GC_INLINE int GC_enough_large_bytes_left(void)
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{
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int n;
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word bytes = GC_large_allocd_bytes;
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GC_ASSERT(GC_max_large_allocd_bytes <= GC_heapsize);
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for (n = N_HBLK_FLS; n >= 0; --n) {
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bytes += GC_free_bytes[n];
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if (bytes >= GC_max_large_allocd_bytes) return n;
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}
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return 0;
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}
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/* Map a number of blocks to the appropriate large block free list index. */
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STATIC int GC_hblk_fl_from_blocks(word blocks_needed)
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{
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if (blocks_needed <= UNIQUE_THRESHOLD) return (int)blocks_needed;
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if (blocks_needed >= HUGE_THRESHOLD) return N_HBLK_FLS;
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return (int)(blocks_needed - UNIQUE_THRESHOLD)/FL_COMPRESSION
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+ UNIQUE_THRESHOLD;
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}
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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
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# define IS_MAPPED(hhdr) TRUE
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# endif /* !USE_MUNMAP */
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#if !defined(NO_DEBUGGING) || defined(GC_ASSERTIONS)
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/* Should return the same value as GC_large_free_bytes. */
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GC_INNER word GC_compute_large_free_bytes(void)
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{
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word total_free = 0;
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unsigned i;
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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struct hblk * h;
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hdr * hhdr;
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for (h = GC_hblkfreelist[i]; h != 0; h = hhdr->hb_next) {
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hhdr = HDR(h);
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total_free += hhdr->hb_sz;
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}
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}
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return total_free;
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}
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#endif /* !NO_DEBUGGING || GC_ASSERTIONS */
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# if !defined(NO_DEBUGGING)
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void GC_print_hblkfreelist(void)
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{
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unsigned i;
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word total;
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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struct hblk * h = GC_hblkfreelist[i];
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if (0 != h) GC_printf("Free list %u (total size %lu):\n",
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i, (unsigned long)GC_free_bytes[i]);
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while (h != 0) {
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hdr * hhdr = HDR(h);
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GC_printf("\t%p size %lu %s black listed\n",
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(void *)h, (unsigned long) hhdr -> hb_sz,
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GC_is_black_listed(h, HBLKSIZE) != 0 ? "start" :
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GC_is_black_listed(h, hhdr -> hb_sz) != 0 ? "partially" :
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"not");
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h = hhdr -> hb_next;
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}
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}
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GC_printf("GC_large_free_bytes: %lu\n",
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(unsigned long)GC_large_free_bytes);
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if ((total = GC_compute_large_free_bytes()) != GC_large_free_bytes)
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GC_err_printf("GC_large_free_bytes INCONSISTENT!! Should be: %lu\n",
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(unsigned long)total);
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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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static int free_list_index_of(hdr *wanted)
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{
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int i;
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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struct hblk * h;
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hdr * hhdr;
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for (h = GC_hblkfreelist[i]; h != 0; h = hhdr -> hb_next) {
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hhdr = HDR(h);
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if (hhdr == wanted) return i;
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}
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}
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return -1;
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}
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GC_API void GC_CALL GC_dump_regions(void)
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{
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unsigned i;
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for (i = 0; i < GC_n_heap_sects; ++i) {
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ptr_t start = GC_heap_sects[i].hs_start;
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size_t bytes = GC_heap_sects[i].hs_bytes;
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ptr_t end = start + bytes;
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ptr_t p;
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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_printf("***Section from %p to %p\n", (void *)start, (void *)end);
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for (p = start; (word)p < (word)end; ) {
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hdr *hhdr = HDR(p);
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if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
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GC_printf("\t%p Missing header!!(%p)\n",
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(void *)p, (void *)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_printf("\t%p\tfree block of size 0x%lx bytes%s\n",
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(void *)p, (unsigned long)(hhdr -> hb_sz),
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IS_MAPPED(hhdr) ? "" : " (unmapped)");
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actual_index = free_list_index_of(hhdr);
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if (-1 == actual_index) {
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GC_printf("\t\tBlock not on free list %d!!\n",
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correct_index);
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} else if (correct_index != actual_index) {
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GC_printf("\t\tBlock on list %d, should be on %d!!\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_printf("\t%p\tused for blocks of size 0x%lx bytes\n",
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(void *)p, (unsigned long)(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(hdr * hhdr, struct hblk *block, size_t byte_sz,
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int kind, unsigned flags)
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{
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word descr;
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# ifdef MARK_BIT_PER_GRANULE
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if (byte_sz > MAXOBJBYTES)
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flags |= LARGE_BLOCK;
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# endif
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# ifdef ENABLE_DISCLAIM
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if (GC_obj_kinds[kind].ok_disclaim_proc)
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flags |= HAS_DISCLAIM;
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if (GC_obj_kinds[kind].ok_mark_unconditionally)
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flags |= MARK_UNCONDITIONALLY;
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# endif
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/* Set size, kind and mark proc fields */
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hhdr -> hb_sz = byte_sz;
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hhdr -> hb_obj_kind = (unsigned char)kind;
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hhdr -> hb_flags = (unsigned char)flags;
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hhdr -> hb_block = block;
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descr = GC_obj_kinds[kind].ok_descriptor;
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if (GC_obj_kinds[kind].ok_relocate_descr) descr += byte_sz;
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hhdr -> hb_descr = descr;
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# ifdef MARK_BIT_PER_OBJ
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/* Set hb_inv_sz as portably as possible. */
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/* We set it to the smallest value such that sz * inv_sz > 2**32 */
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/* This may be more precision than necessary. */
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if (byte_sz > MAXOBJBYTES) {
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hhdr -> hb_inv_sz = LARGE_INV_SZ;
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} else {
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word inv_sz;
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# if CPP_WORDSZ == 64
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inv_sz = ((word)1 << 32)/byte_sz;
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if (((inv_sz*byte_sz) >> 32) == 0) ++inv_sz;
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# else /* 32 bit words */
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GC_ASSERT(byte_sz >= 4);
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inv_sz = ((unsigned)1 << 31)/byte_sz;
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inv_sz *= 2;
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while (inv_sz*byte_sz > byte_sz) ++inv_sz;
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# endif
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hhdr -> hb_inv_sz = inv_sz;
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}
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# endif
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# ifdef MARK_BIT_PER_GRANULE
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{
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size_t granules = BYTES_TO_GRANULES(byte_sz);
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if (EXPECT(!GC_add_map_entry(granules), FALSE)) {
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/* Make it look like a valid block. */
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hhdr -> hb_sz = HBLKSIZE;
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hhdr -> hb_descr = 0;
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hhdr -> hb_flags |= LARGE_BLOCK;
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hhdr -> hb_map = 0;
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return FALSE;
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}
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hhdr -> hb_map = GC_obj_map[(hhdr -> hb_flags & LARGE_BLOCK) != 0 ?
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0 : granules];
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}
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# endif /* MARK_BIT_PER_GRANULE */
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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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/* Remove hhdr from the free list (it is assumed to specified by index). */
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STATIC void GC_remove_from_fl_at(hdr *hhdr, int index)
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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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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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hdr *phdr;
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GET_HDR(hhdr -> hb_prev, phdr);
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phdr -> hb_next = hhdr -> hb_next;
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}
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/* We always need index to maintain free counts. */
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GC_ASSERT(GC_free_bytes[index] >= hhdr -> hb_sz);
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GC_free_bytes[index] -= hhdr -> hb_sz;
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if (0 != hhdr -> hb_next) {
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hdr * nhdr;
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GC_ASSERT(!IS_FORWARDING_ADDR_OR_NIL(NHDR(hhdr)));
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GET_HDR(hhdr -> hb_next, nhdr);
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nhdr -> hb_prev = hhdr -> hb_prev;
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}
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}
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/* Remove hhdr from the appropriate free list (we assume it is on the */
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/* size-appropriate free list). */
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GC_INLINE void GC_remove_from_fl(hdr *hhdr)
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{
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GC_remove_from_fl_at(hhdr, GC_hblk_fl_from_blocks(divHBLKSZ(hhdr->hb_sz)));
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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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STATIC struct hblk * GC_free_block_ending_at(struct hblk *h)
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{
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struct hblk * p = h - 1;
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hdr * phdr;
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GET_HDR(p, phdr);
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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) {
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if(HBLK_IS_FREE(phdr)) {
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return p;
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} else {
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return 0;
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}
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}
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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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/* Add hhdr to the appropriate free list. */
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/* We maintain individual free lists sorted by address. */
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STATIC void GC_add_to_fl(struct hblk *h, 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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# if defined(GC_ASSERTIONS) && !defined(USE_MUNMAP)
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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)
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|| (GC_heapsize & SIGNB) != 0);
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/* In the last case, blocks may be too large to merge. */
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GC_ASSERT(prev == 0 || !HBLK_IS_FREE(prevhdr)
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|| (GC_heapsize & SIGNB) != 0);
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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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GC_free_bytes[index] += hhdr -> hb_sz;
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GC_ASSERT(GC_free_bytes[index] <= GC_large_free_bytes);
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hhdr -> hb_next = second;
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hhdr -> hb_prev = 0;
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if (0 != second) {
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hdr * second_hdr;
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GET_HDR(second, second_hdr);
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second_hdr -> hb_prev = h;
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}
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hhdr -> hb_flags |= FREE_BLK;
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}
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#ifdef USE_MUNMAP
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# ifndef MUNMAP_THRESHOLD
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# define MUNMAP_THRESHOLD 6
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# endif
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GC_INNER int GC_unmap_threshold = MUNMAP_THRESHOLD;
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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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GC_INNER void GC_unmap_old(void)
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{
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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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/* NOTE: Xbox One (DURANGO) may not need to be this aggressive, but the default
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* is likely too lax under heavy allocation pressure. The platform does not
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* have a virtual paging system, so it does not have a large virtual address
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* space that a standard x64 platform has.
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*/
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#if defined(SN_TARGET_PS3) || defined(SN_TARGET_PSP2) || defined(SN_TARGET_ORBIS) || defined(_XBOX_ONE)
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# define UNMAP_THRESHOLD 2
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#else
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# define UNMAP_THRESHOLD 6
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#endif
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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struct hblk * h;
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hdr * hhdr;
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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 || last_rec < threshold)
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&& threshold < GC_gc_no /* 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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# ifdef MPROTECT_VDB
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GC_INNER GC_bool GC_has_unmapped_memory(void)
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{
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int i;
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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struct hblk * h;
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hdr * hhdr;
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for (h = GC_hblkfreelist[i]; h != NULL; h = hhdr -> hb_next) {
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hhdr = HDR(h);
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if (!IS_MAPPED(hhdr)) return TRUE;
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}
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}
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return FALSE;
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}
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# endif /* MPROTECT_VDB */
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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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GC_INNER void GC_merge_unmapped(void)
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{
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int i;
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for (i = 0; i <= N_HBLK_FLS; ++i) {
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struct hblk *h = GC_hblkfreelist[i];
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while (h != 0) {
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struct hblk *next;
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hdr *hhdr, *nexthdr;
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word size, nextsize;
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GET_HDR(h, hhdr);
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size = hhdr->hb_sz;
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next = (struct hblk *)((word)h + size);
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GET_HDR(next, nexthdr);
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/* Coalesce with successor, if possible */
|
|
if (0 != nexthdr && HBLK_IS_FREE(nexthdr)
|
|
&& (signed_word) (size + (nextsize = nexthdr->hb_sz)) > 0
|
|
/* no pot. overflow */) {
|
|
/* Note that we usually try to avoid adjacent free blocks */
|
|
/* that are either both mapped or both unmapped. But that */
|
|
/* isn't guaranteed to hold since we remap blocks when we */
|
|
/* split them, and don't merge at that point. It may also */
|
|
/* not hold if the merged block would be too big. */
|
|
if (IS_MAPPED(hhdr) && !IS_MAPPED(nexthdr)) {
|
|
/* make both consistent, so that we can merge */
|
|
if (size > nextsize) {
|
|
GC_remap((ptr_t)next, nextsize);
|
|
} else {
|
|
GC_unmap((ptr_t)h, size);
|
|
GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
|
|
hhdr -> hb_flags |= WAS_UNMAPPED;
|
|
}
|
|
} else if (IS_MAPPED(nexthdr) && !IS_MAPPED(hhdr)) {
|
|
if (size > nextsize) {
|
|
GC_unmap((ptr_t)next, nextsize);
|
|
GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
|
|
} else {
|
|
GC_remap((ptr_t)h, size);
|
|
hhdr -> hb_flags &= ~WAS_UNMAPPED;
|
|
hhdr -> hb_last_reclaimed = nexthdr -> hb_last_reclaimed;
|
|
}
|
|
} else if (!IS_MAPPED(hhdr) && !IS_MAPPED(nexthdr)) {
|
|
/* Unmap any gap in the middle */
|
|
GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
|
|
}
|
|
/* If they are both unmapped, we merge, but leave unmapped. */
|
|
GC_remove_from_fl_at(hhdr, i);
|
|
GC_remove_from_fl(nexthdr);
|
|
hhdr -> hb_sz += nexthdr -> hb_sz;
|
|
GC_remove_header(next);
|
|
GC_add_to_fl(h, hhdr);
|
|
/* Start over at beginning of list */
|
|
h = GC_hblkfreelist[i];
|
|
} else /* not mergable with successor */ {
|
|
h = hhdr -> hb_next;
|
|
}
|
|
} /* while (h != 0) ... */
|
|
} /* for ... */
|
|
}
|
|
|
|
#endif /* USE_MUNMAP */
|
|
|
|
/*
|
|
* Return a pointer to a block starting at h of length bytes.
|
|
* Memory for the block is mapped.
|
|
* Remove the block from its free list, and return the remainder (if any)
|
|
* to its appropriate free list.
|
|
* May fail by returning 0.
|
|
* The header for the returned block must be set up by the caller.
|
|
* If the return value is not 0, then hhdr is the header for it.
|
|
*/
|
|
STATIC struct hblk * GC_get_first_part(struct hblk *h, hdr *hhdr,
|
|
size_t bytes, int index)
|
|
{
|
|
word total_size = hhdr -> hb_sz;
|
|
struct hblk * rest;
|
|
hdr * rest_hdr;
|
|
|
|
GC_ASSERT((total_size & (HBLKSIZE-1)) == 0);
|
|
GC_remove_from_fl_at(hhdr, index);
|
|
if (total_size == bytes) return h;
|
|
rest = (struct hblk *)((word)h + bytes);
|
|
rest_hdr = GC_install_header(rest);
|
|
if (0 == rest_hdr) {
|
|
/* FIXME: This is likely to be very bad news ... */
|
|
WARN("Header allocation failed: dropping block\n", 0);
|
|
return(0);
|
|
}
|
|
rest_hdr -> hb_sz = total_size - bytes;
|
|
rest_hdr -> hb_flags = 0;
|
|
# ifdef GC_ASSERTIONS
|
|
/* Mark h not free, to avoid assertion about adjacent free blocks. */
|
|
hhdr -> hb_flags &= ~FREE_BLK;
|
|
# endif
|
|
GC_add_to_fl(rest, rest_hdr);
|
|
return h;
|
|
}
|
|
|
|
/*
|
|
* H is a free block. N points at an address inside it.
|
|
* 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.
|
|
* N replaces h in the original free list.
|
|
*
|
|
* Nhdr is not completely filled in, since it is about to allocated.
|
|
* It may in fact end up on the wrong free list for its size.
|
|
* That's not a disaster, since n is about to be allocated
|
|
* by our caller.
|
|
* (Hence adding it to a free list is silly. But this path is hopefully
|
|
* rare enough that it doesn't matter. The code is cleaner this way.)
|
|
*/
|
|
STATIC void GC_split_block(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;
|
|
}
|
|
GC_ASSERT(GC_free_bytes[index] > h_size);
|
|
GC_free_bytes[index] -= h_size;
|
|
# ifdef USE_MUNMAP
|
|
hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
|
|
# endif
|
|
hhdr -> hb_sz = h_size;
|
|
GC_add_to_fl(h, hhdr);
|
|
nhdr -> hb_flags |= FREE_BLK;
|
|
}
|
|
|
|
STATIC struct hblk *
|
|
GC_allochblk_nth(size_t sz /* bytes */, int kind, unsigned flags, int n,
|
|
int may_split);
|
|
#define AVOID_SPLIT_REMAPPED 2
|
|
|
|
/*
|
|
* Allocate (and return pointer to) a heap block
|
|
* for objects of size sz bytes, searching the nth free list.
|
|
*
|
|
* NOTE: We set obj_map field in header correctly.
|
|
* Caller is responsible for building an object freelist in block.
|
|
*
|
|
* The client is responsible for clearing the block, if necessary.
|
|
*/
|
|
GC_INNER struct hblk *
|
|
GC_allochblk(size_t sz, int kind, unsigned flags/* IGNORE_OFF_PAGE or 0 */)
|
|
{
|
|
word blocks;
|
|
int start_list;
|
|
struct hblk *result;
|
|
int may_split;
|
|
int split_limit; /* Highest index of free list whose blocks we */
|
|
/* split. */
|
|
|
|
GC_ASSERT((sz & (GRANULE_BYTES - 1)) == 0);
|
|
blocks = OBJ_SZ_TO_BLOCKS_CHECKED(sz);
|
|
if ((signed_word)(blocks * HBLKSIZE) < 0) {
|
|
return 0;
|
|
}
|
|
start_list = GC_hblk_fl_from_blocks(blocks);
|
|
/* Try for an exact match first. */
|
|
result = GC_allochblk_nth(sz, kind, flags, start_list, FALSE);
|
|
if (0 != result) return result;
|
|
|
|
may_split = TRUE;
|
|
if (GC_use_entire_heap || GC_dont_gc
|
|
|| USED_HEAP_SIZE < GC_requested_heapsize
|
|
|| GC_incremental || !GC_should_collect()) {
|
|
/* Should use more of the heap, even if it requires splitting. */
|
|
split_limit = N_HBLK_FLS;
|
|
} else if (GC_finalizer_bytes_freed > (GC_heapsize >> 4)) {
|
|
/* If we are deallocating lots of memory from */
|
|
/* finalizers, fail and collect sooner rather */
|
|
/* than later. */
|
|
split_limit = 0;
|
|
} else {
|
|
/* If we have enough large blocks left to cover any */
|
|
/* previous request for large blocks, we go ahead */
|
|
/* and split. Assuming a steady state, that should */
|
|
/* be safe. It means that we can use the full */
|
|
/* heap if we allocate only small objects. */
|
|
split_limit = GC_enough_large_bytes_left();
|
|
# ifdef USE_MUNMAP
|
|
if (split_limit > 0)
|
|
may_split = AVOID_SPLIT_REMAPPED;
|
|
# endif
|
|
}
|
|
if (start_list < UNIQUE_THRESHOLD) {
|
|
/* No reason to try start_list again, since all blocks are exact */
|
|
/* matches. */
|
|
++start_list;
|
|
}
|
|
for (; start_list <= split_limit; ++start_list) {
|
|
result = GC_allochblk_nth(sz, kind, flags, start_list, may_split);
|
|
if (0 != result)
|
|
break;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
STATIC long GC_large_alloc_warn_suppressed = 0;
|
|
/* Number of warnings suppressed so far. */
|
|
|
|
/* The same, but with search restricted to nth free list. Flags is */
|
|
/* IGNORE_OFF_PAGE or zero. sz is in bytes. The may_split flag */
|
|
/* indicates whether it is OK to split larger blocks (if set to */
|
|
/* AVOID_SPLIT_REMAPPED then memory remapping followed by splitting */
|
|
/* should be generally avoided). */
|
|
STATIC struct hblk *
|
|
GC_allochblk_nth(size_t sz, int kind, unsigned flags, int n, int may_split)
|
|
{
|
|
struct hblk *hbp;
|
|
hdr * hhdr; /* Header corr. to hbp */
|
|
struct hblk *thishbp;
|
|
hdr * thishdr; /* Header corr. to thishbp */
|
|
signed_word size_needed = HBLKSIZE * OBJ_SZ_TO_BLOCKS_CHECKED(sz);
|
|
/* number of bytes in requested objects */
|
|
|
|
/* search for a big enough block in free list */
|
|
for (hbp = GC_hblkfreelist[n];; hbp = hhdr -> hb_next) {
|
|
signed_word size_avail; /* bytes available in this block */
|
|
|
|
if (NULL == hbp) return NULL;
|
|
GET_HDR(hbp, hhdr); /* set hhdr value */
|
|
size_avail = (signed_word)hhdr->hb_sz;
|
|
if (size_avail < size_needed) continue;
|
|
if (size_avail != size_needed) {
|
|
if (!may_split) continue;
|
|
/* If the next heap block is obviously better, go on. */
|
|
/* This prevents us from disassembling a single large */
|
|
/* block to get tiny blocks. */
|
|
thishbp = hhdr -> hb_next;
|
|
if (thishbp != 0) {
|
|
signed_word next_size;
|
|
|
|
GET_HDR(thishbp, thishdr);
|
|
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 > (signed_word)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) != 0 ?
|
|
(signed_word)HBLKSIZE
|
|
: size_needed;
|
|
|
|
while ((word)lasthbp <= (word)search_end
|
|
&& (thishbp = GC_is_black_listed(lasthbp,
|
|
(word)eff_size_needed)) != 0) {
|
|
lasthbp = thishbp;
|
|
}
|
|
size_avail -= (ptr_t)lasthbp - (ptr_t)hbp;
|
|
thishbp = lasthbp;
|
|
if (size_avail >= size_needed) {
|
|
if (thishbp != hbp) {
|
|
# ifdef USE_MUNMAP
|
|
/* Avoid remapping followed by splitting. */
|
|
if (may_split == AVOID_SPLIT_REMAPPED && !IS_MAPPED(hhdr))
|
|
continue;
|
|
# endif
|
|
thishdr = GC_install_header(thishbp);
|
|
if (0 != thishdr) {
|
|
/* Make sure it's mapped before we mangle it. */
|
|
# ifdef USE_MUNMAP
|
|
if (!IS_MAPPED(hhdr)) {
|
|
GC_remap((ptr_t)hbp, (size_t)hhdr->hb_sz);
|
|
hhdr -> hb_flags &= ~WAS_UNMAPPED;
|
|
}
|
|
# endif
|
|
/* Split the block at 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. */
|
|
if (++GC_large_alloc_warn_suppressed
|
|
>= GC_large_alloc_warn_interval) {
|
|
WARN("Repeated allocation of very large block "
|
|
"(appr. size %" WARN_PRIdPTR "):\n"
|
|
"\tMay lead to memory leak and poor performance\n",
|
|
size_needed);
|
|
GC_large_alloc_warn_suppressed = 0;
|
|
}
|
|
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 pointer-free */
|
|
/* 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_large_free_bytes -= total_size;
|
|
GC_bytes_dropped += total_size;
|
|
GC_remove_from_fl_at(hhdr, n);
|
|
for (h = hbp; (word)h < (word)limit; h++) {
|
|
if (h != hbp) {
|
|
hhdr = GC_install_header(h);
|
|
}
|
|
if (NULL != hhdr) {
|
|
(void)setup_header(hhdr, h, HBLKSIZE, PTRFREE, 0);
|
|
/* Can't fail. */
|
|
if (GC_debugging_started) {
|
|
BZERO(h, HBLKSIZE);
|
|
}
|
|
}
|
|
}
|
|
/* Restore hbp to point at free block */
|
|
hbp = prev;
|
|
if (0 == hbp) {
|
|
return GC_allochblk_nth(sz, kind, flags, n, may_split);
|
|
}
|
|
hhdr = HDR(hbp);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if( size_avail >= size_needed ) {
|
|
# ifdef USE_MUNMAP
|
|
if (!IS_MAPPED(hhdr)) {
|
|
GC_remap((ptr_t)hbp, (size_t)hhdr->hb_sz);
|
|
hhdr -> hb_flags &= ~WAS_UNMAPPED;
|
|
/* Note: This may leave adjacent, mapped free blocks. */
|
|
}
|
|
# 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;
|
|
|
|
/* 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, hbp, sz, kind, flags)) {
|
|
GC_remove_counts(hbp, (word)size_needed);
|
|
return(0); /* ditto */
|
|
}
|
|
# ifndef GC_DISABLE_INCREMENTAL
|
|
/* Notify virtual dirty bit implementation that we are about to */
|
|
/* write. Ensure that pointer-free objects are not protected */
|
|
/* if it is avoidable. This also ensures that newly allocated */
|
|
/* blocks are treated as dirty. Necessary since we don't */
|
|
/* protect free blocks. */
|
|
GC_ASSERT((size_needed & (HBLKSIZE-1)) == 0);
|
|
GC_remove_protection(hbp, divHBLKSZ(size_needed),
|
|
(hhdr -> hb_descr == 0) /* pointer-free */);
|
|
# endif
|
|
/* We just successfully allocated a block. Restart count of */
|
|
/* consecutive failures. */
|
|
GC_fail_count = 0;
|
|
|
|
GC_large_free_bytes -= size_needed;
|
|
GC_ASSERT(IS_MAPPED(hhdr));
|
|
return( hbp );
|
|
}
|
|
|
|
/*
|
|
* Free a heap block.
|
|
*
|
|
* Coalesce the block with its neighbors if possible.
|
|
*
|
|
* All mark words are assumed to be cleared.
|
|
*/
|
|
GC_INNER void GC_freehblk(struct hblk *hbp)
|
|
{
|
|
struct hblk *next, *prev;
|
|
hdr *hhdr, *prevhdr, *nexthdr;
|
|
word size;
|
|
|
|
GET_HDR(hbp, hhdr);
|
|
size = HBLKSIZE * OBJ_SZ_TO_BLOCKS(hhdr->hb_sz);
|
|
if ((signed_word)size <= 0)
|
|
ABORT("Deallocating excessively large block. Too large an allocation?");
|
|
/* Probably possible if we try to allocate more than half the address */
|
|
/* space at once. If we don't catch it here, strange things happen */
|
|
/* later. */
|
|
GC_remove_counts(hbp, size);
|
|
hhdr->hb_sz = size;
|
|
# ifdef USE_MUNMAP
|
|
hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
|
|
# endif
|
|
|
|
/* Check for duplicate deallocation in the easy case */
|
|
if (HBLK_IS_FREE(hhdr)) {
|
|
ABORT_ARG1("Duplicate large block deallocation",
|
|
" of %p", (void *)hbp);
|
|
}
|
|
|
|
GC_ASSERT(IS_MAPPED(hhdr));
|
|
hhdr -> hb_flags |= FREE_BLK;
|
|
next = (struct hblk *)((ptr_t)hbp + size);
|
|
GET_HDR(next, nexthdr);
|
|
prev = GC_free_block_ending_at(hbp);
|
|
/* Coalesce with successor, if possible */
|
|
if(0 != nexthdr && HBLK_IS_FREE(nexthdr) && IS_MAPPED(nexthdr)
|
|
&& (signed_word)(hhdr -> hb_sz + nexthdr -> hb_sz) > 0
|
|
/* no overflow */) {
|
|
GC_remove_from_fl(nexthdr);
|
|
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)
|
|
&& (signed_word)(hhdr -> hb_sz + prevhdr -> hb_sz) > 0) {
|
|
GC_remove_from_fl(prevhdr);
|
|
prevhdr -> hb_sz += hhdr -> hb_sz;
|
|
# ifdef USE_MUNMAP
|
|
prevhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
|
|
# endif
|
|
GC_remove_header(hbp);
|
|
hbp = prev;
|
|
hhdr = prevhdr;
|
|
}
|
|
}
|
|
/* FIXME: It is not clear we really always want to do these merges */
|
|
/* with USE_MUNMAP, since it updates ages and hence prevents */
|
|
/* unmapping. */
|
|
|
|
GC_large_free_bytes += size;
|
|
GC_add_to_fl(hbp, hhdr);
|
|
}
|