1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/referencePolicy.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,81 @@
1.4 +/*
1.5 + * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_MEMORY_REFERENCEPOLICY_HPP
1.29 +#define SHARE_VM_MEMORY_REFERENCEPOLICY_HPP
1.30 +
1.31 +// referencePolicy is used to determine when soft reference objects
1.32 +// should be cleared.
1.33 +
1.34 +
1.35 +class ReferencePolicy : public CHeapObj<mtGC> {
1.36 + public:
1.37 + virtual bool should_clear_reference(oop p, jlong timestamp_clock) {
1.38 + ShouldNotReachHere();
1.39 + return true;
1.40 + }
1.41 +
1.42 + // Capture state (of-the-VM) information needed to evaluate the policy
1.43 + virtual void setup() { /* do nothing */ }
1.44 +};
1.45 +
1.46 +class NeverClearPolicy : public ReferencePolicy {
1.47 + public:
1.48 + virtual bool should_clear_reference(oop p, jlong timestamp_clock) {
1.49 + return false;
1.50 + }
1.51 +};
1.52 +
1.53 +class AlwaysClearPolicy : public ReferencePolicy {
1.54 + public:
1.55 + virtual bool should_clear_reference(oop p, jlong timestamp_clock) {
1.56 + return true;
1.57 + }
1.58 +};
1.59 +
1.60 +class LRUCurrentHeapPolicy : public ReferencePolicy {
1.61 + private:
1.62 + jlong _max_interval;
1.63 +
1.64 + public:
1.65 + LRUCurrentHeapPolicy();
1.66 +
1.67 + // Capture state (of-the-VM) information needed to evaluate the policy
1.68 + void setup();
1.69 + virtual bool should_clear_reference(oop p, jlong timestamp_clock);
1.70 +};
1.71 +
1.72 +class LRUMaxHeapPolicy : public ReferencePolicy {
1.73 + private:
1.74 + jlong _max_interval;
1.75 +
1.76 + public:
1.77 + LRUMaxHeapPolicy();
1.78 +
1.79 + // Capture state (of-the-VM) information needed to evaluate the policy
1.80 + void setup();
1.81 + virtual bool should_clear_reference(oop p, jlong timestamp_clock);
1.82 +};
1.83 +
1.84 +#endif // SHARE_VM_MEMORY_REFERENCEPOLICY_HPP
