Mercurial > hg > truffle
comparison src/share/vm/gc_implementation/shared/spaceDecorator.cpp @ 269:850fdf70db2b
Merge
author | jmasa |
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date | Mon, 28 Jul 2008 15:30:23 -0700 |
parents | 12eea04c8b06 |
children | 818a18cd69a8 |
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238:3df2fe7c4451 | 269:850fdf70db2b |
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1 /* | |
2 * Copyright 2002-2005 Sun Microsystems, Inc. All Rights Reserved. | |
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_spaceDecorator.cpp.incl" | |
27 | |
28 // Catch-all file for utility classes | |
29 | |
30 #ifndef PRODUCT | |
31 | |
32 // Returns true is the location q matches the mangling | |
33 // pattern. | |
34 bool SpaceMangler::is_mangled(HeapWord* q) { | |
35 // This test loses precision but is good enough | |
36 return badHeapWord == (max_juint & (uintptr_t) q->value()); | |
37 } | |
38 | |
39 | |
40 void SpaceMangler::set_top_for_allocations(HeapWord* v) { | |
41 if (v < end()) { | |
42 assert(is_mangled(v), "The high water mark is not mangled"); | |
43 } | |
44 _top_for_allocations = v; | |
45 } | |
46 | |
47 // Mangle only the unused space that has not previously | |
48 // been mangled and that has not been allocated since being | |
49 // mangled. | |
50 void SpaceMangler::mangle_unused_area() { | |
51 assert(ZapUnusedHeapArea, "Mangling should not be in use"); | |
52 // Mangle between top and the high water mark. Safeguard | |
53 // against the space changing since top_for_allocations was | |
54 // set. | |
55 HeapWord* mangled_end = MIN2(top_for_allocations(), end()); | |
56 if (top() < mangled_end) { | |
57 MemRegion mangle_mr(top(), mangled_end); | |
58 SpaceMangler::mangle_region(mangle_mr); | |
59 // Light weight check of mangling. | |
60 check_mangled_unused_area(end()); | |
61 } | |
62 // Complete check of unused area which is functional when | |
63 // DEBUG_MANGLING is defined. | |
64 check_mangled_unused_area_complete(); | |
65 } | |
66 | |
67 // A complete mangle is expected in the | |
68 // exceptional case where top_for_allocations is not | |
69 // properly tracking the high water mark for mangling. | |
70 // This can be the case when to-space is being used for | |
71 // scratch space during a mark-sweep-compact. See | |
72 // contribute_scratch() and PSMarkSweep::allocate_stacks(). | |
73 void SpaceMangler::mangle_unused_area_complete() { | |
74 assert(ZapUnusedHeapArea, "Mangling should not be in use"); | |
75 MemRegion mangle_mr(top(), end()); | |
76 SpaceMangler::mangle_region(mangle_mr); | |
77 } | |
78 | |
79 // Simply mangle the MemRegion mr. | |
80 void SpaceMangler::mangle_region(MemRegion mr) { | |
81 assert(ZapUnusedHeapArea, "Mangling should not be in use"); | |
82 #ifdef ASSERT | |
83 if(TraceZapUnusedHeapArea) { | |
84 gclog_or_tty->print("Mangling [0x%x to 0x%x)", mr.start(), mr.end()); | |
85 } | |
86 Copy::fill_to_words(mr.start(), mr.word_size(), badHeapWord); | |
87 if(TraceZapUnusedHeapArea) { | |
88 gclog_or_tty->print_cr(" done"); | |
89 } | |
90 #endif | |
91 } | |
92 | |
93 // Check that top, top_for_allocations and the last | |
94 // word of the space are mangled. In a tight memory | |
95 // situation even this light weight mangling could | |
96 // cause paging by touching the end of the space. | |
97 void SpaceMangler::check_mangled_unused_area(HeapWord* limit) { | |
98 if (CheckZapUnusedHeapArea) { | |
99 // This method can be called while the spaces are | |
100 // being reshaped so skip the test if the end of the | |
101 // space is beyond the specified limit; | |
102 if (end() > limit) return; | |
103 | |
104 assert(top() == end() || | |
105 (is_mangled(top())), "Top not mangled"); | |
106 assert((top_for_allocations() < top()) || | |
107 (top_for_allocations() >= end()) || | |
108 (is_mangled(top_for_allocations())), | |
109 "Older unused not mangled"); | |
110 assert(top() == end() || | |
111 (is_mangled(end() - 1)), "End not properly mangled"); | |
112 // Only does checking when DEBUG_MANGLING is defined. | |
113 check_mangled_unused_area_complete(); | |
114 } | |
115 } | |
116 | |
117 #undef DEBUG_MANGLING | |
118 // This should only be used while debugging the mangling | |
119 // because of the high cost of checking the completeness. | |
120 void SpaceMangler::check_mangled_unused_area_complete() { | |
121 if (CheckZapUnusedHeapArea) { | |
122 assert(ZapUnusedHeapArea, "Not mangling unused area"); | |
123 #ifdef DEBUG_MANGLING | |
124 HeapWord* q = top(); | |
125 HeapWord* limit = end(); | |
126 | |
127 bool passed = true; | |
128 while (q < limit) { | |
129 if (!is_mangled(q)) { | |
130 passed = false; | |
131 break; | |
132 } | |
133 q++; | |
134 } | |
135 assert(passed, "Mangling is not complete"); | |
136 #endif | |
137 } | |
138 } | |
139 #undef DEBUG_MANGLING | |
140 #endif // not PRODUCT |