/* * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved. * Copyright (c) 2000 by Hewlett-Packard Company. All rights reserved. * * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. * * Permission is hereby granted to use or copy this program * for any purpose, provided the above notices are retained on all copies. * Permission to modify the code and to distribute modified code is granted, * provided the above notices are retained, and a notice that the code was * modified is included with the above copyright notice.
*/
#include"private/gc_priv.h"
/* * This file contains the functions: * ptr_t GC_build_flXXX(h, old_fl) * void GC_new_hblk(size, kind)
*/
#include <stdio.h>
#ifndef SMALL_CONFIG /* Build a free list for size 2 (words) cleared objects inside */ /* hblk h. Set the last link to be ofl. Return a pointer to the */ /* first free list entry. */ STATIC ptr_t GC_build_fl_clear2(struct hblk *h, ptr_t ofl)
{
word * p = (word *)(h -> hb_body);
word * lim = (word *)(h + 1);
/* Build a free list for objects of size sz inside heap block h. */ /* Clear objects inside h if clear is set. Add list to the end of */ /* the free list we build. Return the new free list. */ /* This could be called without the main GC lock, if we ensure that */ /* there is no concurrent collection which might reclaim objects that */ /* we have not yet allocated. */
GC_INNER ptr_t GC_build_fl(struct hblk *h, size_t sz, GC_bool clear,
ptr_t list)
{
word *p, *prev;
word *last_object; /* points to last object in new hblk */
/* Do a few prefetches here, just because its cheap. */ /* If we were more serious about it, these should go inside */ /* the loops. But write prefetches usually don't seem to */ /* matter much. */
GC_PREFETCH_FOR_WRITE((ptr_t)h);
GC_PREFETCH_FOR_WRITE((ptr_t)h + 128);
GC_PREFETCH_FOR_WRITE((ptr_t)h + 256);
GC_PREFETCH_FOR_WRITE((ptr_t)h + 378); # ifndef SMALL_CONFIG /* Handle small objects sizes more efficiently. For larger objects */ /* the difference is less significant. */ switch (sz) { case 2: if (clear) { return GC_build_fl_clear2(h, list);
} else { return GC_build_fl2(h, list);
} case 4: if (clear) { return GC_build_fl_clear4(h, list);
} else { return GC_build_fl4(h, list);
} default: break;
} # endif /* !SMALL_CONFIG */
/* Clear the page if necessary. */ if (clear) BZERO(h, HBLKSIZE);
/* Add objects to free list */
p = (word *)(h -> hb_body) + sz; /* second object in *h */
prev = (word *)(h -> hb_body); /* One object behind p */
last_object = (word *)((char *)h + HBLKSIZE);
last_object -= sz; /* Last place for last object to start */
/* make a list of all objects in *h with head as last object */ while ((word)p <= (word)last_object) { /* current object's link points to last object */
obj_link(p) = (ptr_t)prev;
prev = p;
p += sz;
}
p -= sz; /* p now points to last object */
/* Put p (which is now head of list of objects in *h) as first */ /* pointer in the appropriate free list for this size. */
*(ptr_t *)h = list; return ((ptr_t)p);
}
/* Allocate a new heapblock for small objects of size gran granules. */ /* Add all of the heapblock's objects to the free list for objects */ /* of that size. Set all mark bits if objects are uncollectible. */ /* Will fail to do anything if we are out of memory. */
GC_INNER void GC_new_hblk(size_t gran, int kind)
{ struct hblk *h; /* the new heap block */
GC_bool clear = GC_obj_kinds[kind].ok_init;
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