1 /*
2 * Copyright (c) 2000, 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 // referencePolicy is used to determine when soft reference objects
26 // should be cleared.
27
28
29 class ReferencePolicy : public CHeapObj {
30 public:
31 virtual bool should_clear_reference(oop p) { ShouldNotReachHere(); return true; }
32 // Capture state (of-the-VM) information needed to evaluate the policy
33 virtual void setup() { /* do nothing */ }
34 };
35
36 class NeverClearPolicy : public ReferencePolicy {
37 public:
38 bool should_clear_reference(oop p) { return false; }
39 };
40
41 class AlwaysClearPolicy : public ReferencePolicy {
42 public:
43 bool should_clear_reference(oop p) { return true; }
44 };
49
50 public:
51 LRUCurrentHeapPolicy();
52
53 // Capture state (of-the-VM) information needed to evaluate the policy
54 void setup();
55 bool should_clear_reference(oop p);
56 };
57
58 class LRUMaxHeapPolicy : public ReferencePolicy {
59 private:
60 jlong _max_interval;
61
62 public:
63 LRUMaxHeapPolicy();
64
65 // Capture state (of-the-VM) information needed to evaluate the policy
66 void setup();
67 bool should_clear_reference(oop p);
68 };
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1 /*
2 * Copyright (c) 2000, 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_MEMORY_REFERENCEPOLICY_HPP
26 #define SHARE_VM_MEMORY_REFERENCEPOLICY_HPP
27
28 // referencePolicy is used to determine when soft reference objects
29 // should be cleared.
30
31
32 class ReferencePolicy : public CHeapObj {
33 public:
34 virtual bool should_clear_reference(oop p) { ShouldNotReachHere(); return true; }
35 // Capture state (of-the-VM) information needed to evaluate the policy
36 virtual void setup() { /* do nothing */ }
37 };
38
39 class NeverClearPolicy : public ReferencePolicy {
40 public:
41 bool should_clear_reference(oop p) { return false; }
42 };
43
44 class AlwaysClearPolicy : public ReferencePolicy {
45 public:
46 bool should_clear_reference(oop p) { return true; }
47 };
52
53 public:
54 LRUCurrentHeapPolicy();
55
56 // Capture state (of-the-VM) information needed to evaluate the policy
57 void setup();
58 bool should_clear_reference(oop p);
59 };
60
61 class LRUMaxHeapPolicy : public ReferencePolicy {
62 private:
63 jlong _max_interval;
64
65 public:
66 LRUMaxHeapPolicy();
67
68 // Capture state (of-the-VM) information needed to evaluate the policy
69 void setup();
70 bool should_clear_reference(oop p);
71 };
72
73 #endif // SHARE_VM_MEMORY_REFERENCEPOLICY_HPP
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