1/*
2 * Copyright (c) 2000, 2015, 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#include "precompiled.hpp"
26#include "classfile/javaClasses.hpp"
27#include "gc/shared/referencePolicy.hpp"
28#include "memory/universe.hpp"
29#include "runtime/arguments.hpp"
30#include "runtime/globals.hpp"
31
32LRUCurrentHeapPolicy::LRUCurrentHeapPolicy() {
33 setup();
34}
35
36// Capture state (of-the-VM) information needed to evaluate the policy
37void LRUCurrentHeapPolicy::setup() {
38 _max_interval = (Universe::get_heap_free_at_last_gc() / M) * SoftRefLRUPolicyMSPerMB;
39 assert(_max_interval >= 0,"Sanity check");
40}
41
42// The oop passed in is the SoftReference object, and not
43// the object the SoftReference points to.
44bool LRUCurrentHeapPolicy::should_clear_reference(oop p,
45 jlong timestamp_clock) {
46 jlong interval = timestamp_clock - java_lang_ref_SoftReference::timestamp(p);
47 assert(interval >= 0, "Sanity check");
48
49 // The interval will be zero if the ref was accessed since the last scavenge/gc.
50 if(interval <= _max_interval) {
51 return false;
52 }
53
54 return true;
55}
56
57/////////////////////// MaxHeap //////////////////////
58
59LRUMaxHeapPolicy::LRUMaxHeapPolicy() {
60 setup();
61}
62
63// Capture state (of-the-VM) information needed to evaluate the policy
64void LRUMaxHeapPolicy::setup() {
65 size_t max_heap = MaxHeapSize;
66 max_heap -= Universe::get_heap_used_at_last_gc();
67 max_heap /= M;
68
69 _max_interval = max_heap * SoftRefLRUPolicyMSPerMB;
70 assert(_max_interval >= 0,"Sanity check");
71}
72
73// The oop passed in is the SoftReference object, and not
74// the object the SoftReference points to.
75bool LRUMaxHeapPolicy::should_clear_reference(oop p,
76 jlong timestamp_clock) {
77 jlong interval = timestamp_clock - java_lang_ref_SoftReference::timestamp(p);
78 assert(interval >= 0, "Sanity check");
79
80 // The interval will be zero if the ref was accessed since the last scavenge/gc.
81 if(interval <= _max_interval) {
82 return false;
83 }
84
85 return true;
86}
87