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comparison src/share/vm/gc_implementation/parallelScavenge/psPromotionLAB.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 2002-2006 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/_psPromotionLAB.cpp.incl"
27
28 const size_t PSPromotionLAB::filler_header_size = align_object_size(typeArrayOopDesc::header_size(T_INT));
29
30 // This is the shared initialization code. It sets up the basic pointers,
31 // and allows enough extra space for a filler object. We call a virtual
32 // method, "lab_is_valid()" to handle the different asserts the old/young
33 // labs require.
34 void PSPromotionLAB::initialize(MemRegion lab) {
35 assert(lab_is_valid(lab), "Sanity");
36
37 HeapWord* bottom = lab.start();
38 HeapWord* end = lab.end();
39
40 set_bottom(bottom);
41 set_end(end);
42 set_top(bottom);
43
44 // We can be initialized to a zero size!
45 if (free() > 0) {
46 if (ZapUnusedHeapArea) {
47 debug_only(Copy::fill_to_words(top(), free()/HeapWordSize, badHeapWord));
48 }
49
50 // NOTE! We need to allow space for a filler object.
51 assert(lab.word_size() >= filler_header_size, "lab is too small");
52 end = end - filler_header_size;
53 set_end(end);
54
55 _state = needs_flush;
56 } else {
57 _state = zero_size;
58 }
59
60 assert(this->top() <= this->end(), "pointers out of order");
61 }
62
63 // Fill all remaining lab space with an unreachable object.
64 // The goal is to leave a contiguous parseable span of objects.
65 void PSPromotionLAB::flush() {
66 assert(_state != flushed, "Attempt to flush PLAB twice");
67 assert(top() <= end(), "pointers out of order");
68
69 // If we were initialized to a zero sized lab, there is
70 // nothing to flush
71 if (_state == zero_size)
72 return;
73
74 // PLAB's never allocate the last aligned_header_size
75 // so they can always fill with an array.
76 HeapWord* tlab_end = end() + filler_header_size;
77 typeArrayOop filler_oop = (typeArrayOop) top();
78 filler_oop->set_mark(markOopDesc::prototype());
79 filler_oop->set_klass(Universe::intArrayKlassObj());
80 const size_t array_length =
81 pointer_delta(tlab_end, top()) - typeArrayOopDesc::header_size(T_INT);
82 assert( (array_length * (HeapWordSize/sizeof(jint))) < (size_t)max_jint, "array too big in PSPromotionLAB");
83 filler_oop->set_length((int)(array_length * (HeapWordSize/sizeof(jint))));
84
85 #ifdef ASSERT
86 // Note that we actually DO NOT want to use the aligned header size!
87 HeapWord* elt_words = ((HeapWord*)filler_oop) + typeArrayOopDesc::header_size(T_INT);
88 Copy::fill_to_words(elt_words, array_length, 0xDEAABABE);
89 #endif
90
91 set_bottom(NULL);
92 set_end(NULL);
93 set_top(NULL);
94
95 _state = flushed;
96 }
97
98 bool PSPromotionLAB::unallocate_object(oop obj) {
99 assert(Universe::heap()->is_in(obj), "Object outside heap");
100
101 if (contains(obj)) {
102 HeapWord* object_end = (HeapWord*)obj + obj->size();
103 assert(object_end <= top(), "Object crosses promotion LAB boundary");
104
105 if (object_end == top()) {
106 set_top((HeapWord*)obj);
107 return true;
108 }
109 }
110
111 return false;
112 }
113
114 // Fill all remaining lab space with an unreachable object.
115 // The goal is to leave a contiguous parseable span of objects.
116 void PSOldPromotionLAB::flush() {
117 assert(_state != flushed, "Attempt to flush PLAB twice");
118 assert(top() <= end(), "pointers out of order");
119
120 if (_state == zero_size)
121 return;
122
123 HeapWord* obj = top();
124
125 PSPromotionLAB::flush();
126
127 assert(_start_array != NULL, "Sanity");
128
129 _start_array->allocate_block(obj);
130 }
131
132 #ifdef ASSERT
133
134 bool PSYoungPromotionLAB::lab_is_valid(MemRegion lab) {
135 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
136 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
137
138 MutableSpace* to_space = heap->young_gen()->to_space();
139 MemRegion used = to_space->used_region();
140 if (used.contains(lab)) {
141 return true;
142 }
143
144 return false;
145 }
146
147 bool PSOldPromotionLAB::lab_is_valid(MemRegion lab) {
148 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
149 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
150 assert(_start_array->covered_region().contains(lab), "Sanity");
151
152 PSOldGen* old_gen = heap->old_gen();
153 MemRegion used = old_gen->object_space()->used_region();
154
155 if (used.contains(lab)) {
156 return true;
157 }
158
159 return false;
160 }
161
162 #endif /* ASSERT */