2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
4 * Copyright (c) 2000 by Hewlett-Packard Company. All rights reserved.
6 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
7 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
9 * Permission is hereby granted to use or copy this program
10 * for any purpose, provided the above notices are retained on all copies.
11 * Permission to modify the code and to distribute modified code is granted,
12 * provided the above notices are retained, and a notice that the code was
13 * modified is included with the above copyright notice.
16 #include "private/gc_priv.h"
19 * This file contains the functions:
20 * ptr_t GC_build_flXXX(h, old_fl)
21 * void GC_new_hblk(size)
27 /* Build a free list for size 2 (words) cleared objects inside */
28 /* hblk h. Set the last link to be ofl. Return a pointer tpo the */
29 /* first free list entry. */
30 STATIC ptr_t GC_build_fl_clear2(struct hblk *h, ptr_t ofl)
32 word * p = (word *)(h -> hb_body);
33 word * lim = (word *)(h + 1);
40 for (; p < lim; p += 4) {
49 /* The same for size 4 cleared objects. */
50 STATIC ptr_t GC_build_fl_clear4(struct hblk *h, ptr_t ofl)
52 word * p = (word *)(h -> hb_body);
53 word * lim = (word *)(h + 1);
60 for (; p < lim; p += 4) {
61 PREFETCH_FOR_WRITE((ptr_t)(p+64));
69 /* The same for size 2 uncleared objects. */
70 STATIC ptr_t GC_build_fl2(struct hblk *h, ptr_t ofl)
72 word * p = (word *)(h -> hb_body);
73 word * lim = (word *)(h + 1);
78 for (; p < lim; p += 4) {
85 /* The same for size 4 uncleared objects. */
86 STATIC ptr_t GC_build_fl4(struct hblk *h, ptr_t ofl)
88 word * p = (word *)(h -> hb_body);
89 word * lim = (word *)(h + 1);
94 for (; p < lim; p += 8) {
95 PREFETCH_FOR_WRITE((ptr_t)(p+64));
101 #endif /* !SMALL_CONFIG */
103 /* Build a free list for objects of size sz inside heap block h. */
104 /* Clear objects inside h if clear is set. Add list to the end of */
105 /* the free list we build. Return the new free list. */
106 /* This could be called without the main GC lock, if we ensure that */
107 /* there is no concurrent collection which might reclaim objects that */
108 /* we have not yet allocated. */
109 GC_INNER ptr_t GC_build_fl(struct hblk *h, size_t sz, GC_bool clear,
113 word *last_object; /* points to last object in new hblk */
115 /* Do a few prefetches here, just because its cheap. */
116 /* If we were more serious about it, these should go inside */
117 /* the loops. But write prefetches usually don't seem to */
119 PREFETCH_FOR_WRITE((ptr_t)h);
120 PREFETCH_FOR_WRITE((ptr_t)h + 128);
121 PREFETCH_FOR_WRITE((ptr_t)h + 256);
122 PREFETCH_FOR_WRITE((ptr_t)h + 378);
123 # ifndef SMALL_CONFIG
124 /* Handle small objects sizes more efficiently. For larger objects */
125 /* the difference is less significant. */
128 return GC_build_fl_clear2(h, list);
130 return GC_build_fl2(h, list);
133 return GC_build_fl_clear4(h, list);
135 return GC_build_fl4(h, list);
140 # endif /* !SMALL_CONFIG */
142 /* Clear the page if necessary. */
143 if (clear) BZERO(h, HBLKSIZE);
145 /* Add objects to free list */
146 p = (word *)(h -> hb_body) + sz; /* second object in *h */
147 prev = (word *)(h -> hb_body); /* One object behind p */
148 last_object = (word *)((char *)h + HBLKSIZE);
150 /* Last place for last object to start */
152 /* make a list of all objects in *h with head as last object */
153 while (p <= last_object) {
154 /* current object's link points to last object */
155 obj_link(p) = (ptr_t)prev;
159 p -= sz; /* p now points to last object */
161 /* Put p (which is now head of list of objects in *h) as first */
162 /* pointer in the appropriate free list for this size. */
168 * Allocate a new heapblock for small objects of size gran granules.
169 * Add all of the heapblock's objects to the free list for objects
171 * Set all mark bits if objects are uncollectable.
172 * Will fail to do anything if we are out of memory.
174 GC_INNER void GC_new_hblk(size_t gran, int kind)
176 struct hblk *h; /* the new heap block */
177 GC_bool clear = GC_obj_kinds[kind].ok_init;
179 GC_STATIC_ASSERT((sizeof (struct hblk)) == HBLKSIZE);
181 if (GC_debugging_started) clear = TRUE;
183 /* Allocate a new heap block */
184 h = GC_allochblk(GRANULES_TO_BYTES(gran), kind, 0);
187 /* Mark all objects if appropriate. */
188 if (IS_UNCOLLECTABLE(kind)) GC_set_hdr_marks(HDR(h));
190 /* Build the free list */
191 GC_obj_kinds[kind].ok_freelist[gran] =
192 GC_build_fl(h, GRANULES_TO_WORDS(gran), clear,
193 GC_obj_kinds[kind].ok_freelist[gran]);