1 /*
2 * Copyright (c) 2002, 2008, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 //
26 // PSPromotionLAB is a parallel scavenge promotion lab. This class acts very
27 // much like a MutableSpace. We couldn't embed a MutableSpace, though, as
28 // it has a considerable number of asserts and invariants that are violated.
29 //
30
31 class ObjectStartArray;
32
33 class PSPromotionLAB : public CHeapObj {
34 protected:
35 static size_t filler_header_size;
36
37 enum LabState {
38 needs_flush,
39 flushed,
40 zero_size
41 };
42
43 HeapWord* _top;
44 HeapWord* _bottom;
123 HeapWord* allocate(size_t size) {
124 // Cannot test for this now that we're doing promotion failures
125 // assert(_state != flushed, "Sanity");
126 assert(_start_array != NULL, "Sanity");
127 HeapWord* obj = top();
128 HeapWord* new_top = obj + size;
129 // The 'new_top>obj' check is needed to detect overflow of obj+size.
130 if (new_top > obj && new_top <= end()) {
131 set_top(new_top);
132 assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
133 "checking alignment");
134 _start_array->allocate_block(obj);
135 return obj;
136 }
137
138 return NULL;
139 }
140
141 debug_only(virtual bool lab_is_valid(MemRegion lab));
142 };
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1 /*
2 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPROMOTIONLAB_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPROMOTIONLAB_HPP
27
28 #include "gc_implementation/parallelScavenge/objectStartArray.hpp"
29 #include "memory/allocation.hpp"
30
31 //
32 // PSPromotionLAB is a parallel scavenge promotion lab. This class acts very
33 // much like a MutableSpace. We couldn't embed a MutableSpace, though, as
34 // it has a considerable number of asserts and invariants that are violated.
35 //
36
37 class ObjectStartArray;
38
39 class PSPromotionLAB : public CHeapObj {
40 protected:
41 static size_t filler_header_size;
42
43 enum LabState {
44 needs_flush,
45 flushed,
46 zero_size
47 };
48
49 HeapWord* _top;
50 HeapWord* _bottom;
129 HeapWord* allocate(size_t size) {
130 // Cannot test for this now that we're doing promotion failures
131 // assert(_state != flushed, "Sanity");
132 assert(_start_array != NULL, "Sanity");
133 HeapWord* obj = top();
134 HeapWord* new_top = obj + size;
135 // The 'new_top>obj' check is needed to detect overflow of obj+size.
136 if (new_top > obj && new_top <= end()) {
137 set_top(new_top);
138 assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
139 "checking alignment");
140 _start_array->allocate_block(obj);
141 return obj;
142 }
143
144 return NULL;
145 }
146
147 debug_only(virtual bool lab_is_valid(MemRegion lab));
148 };
149
150 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPROMOTIONLAB_HPP
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