1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
/*
* 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)
*/
#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);
p[0] = (word)ofl;
p[1] = 0;
p[2] = (word)p;
p[3] = 0;
p += 4;
for (; (word)p < (word)lim; p += 4) {
p[0] = (word)(p-2);
p[1] = 0;
p[2] = (word)p;
p[3] = 0;
};
return((ptr_t)(p-2));
}
/* The same for size 4 cleared objects. */
STATIC ptr_t GC_build_fl_clear4(struct hblk *h, ptr_t ofl)
{
word * p = (word *)(h -> hb_body);
word * lim = (word *)(h + 1);
p[0] = (word)ofl;
p[1] = 0;
p[2] = 0;
p[3] = 0;
p += 4;
for (; (word)p < (word)lim; p += 4) {
GC_PREFETCH_FOR_WRITE((ptr_t)(p + 64));
p[0] = (word)(p-4);
p[1] = 0;
CLEAR_DOUBLE(p+2);
};
return((ptr_t)(p-4));
}
/* The same for size 2 uncleared objects. */
STATIC ptr_t GC_build_fl2(struct hblk *h, ptr_t ofl)
{
word * p = (word *)(h -> hb_body);
word * lim = (word *)(h + 1);
p[0] = (word)ofl;
p[2] = (word)p;
p += 4;
for (; (word)p < (word)lim; p += 4) {
p[0] = (word)(p-2);
p[2] = (word)p;
};
return((ptr_t)(p-2));
}
/* The same for size 4 uncleared objects. */
STATIC ptr_t GC_build_fl4(struct hblk *h, ptr_t ofl)
{
word * p = (word *)(h -> hb_body);
word * lim = (word *)(h + 1);
p[0] = (word)ofl;
p[4] = (word)p;
p += 8;
for (; (word)p < (word)lim; p += 8) {
GC_PREFETCH_FOR_WRITE((ptr_t)(p + 64));
p[0] = (word)(p-4);
p[4] = (word)p;
};
return((ptr_t)(p-4));
}
#endif /* !SMALL_CONFIG */
/* 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;
GC_STATIC_ASSERT((sizeof (struct hblk)) == HBLKSIZE);
if (GC_debugging_started) clear = TRUE;
/* Allocate a new heap block */
h = GC_allochblk(GRANULES_TO_BYTES(gran), kind, 0);
if (h == 0) return;
/* Mark all objects if appropriate. */
if (IS_UNCOLLECTABLE(kind)) GC_set_hdr_marks(HDR(h));
/* Build the free list */
GC_obj_kinds[kind].ok_freelist[gran] =
GC_build_fl(h, GRANULES_TO_WORDS(gran), clear,
(ptr_t)GC_obj_kinds[kind].ok_freelist[gran]);
}
|
