1/*
2 * Copyright (c) 2017, 2018, 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 "jfr/leakprofiler/sampling/objectSample.hpp"
27#include "jfr/leakprofiler/sampling/sampleList.hpp"
28#include "oops/oop.inline.hpp"
29
30SampleList::SampleList(size_t limit, size_t cache_size) :
31 _free_list(),
32 _in_use_list(),
33 _last_resolved(NULL),
34 _allocated(0),
35 _limit(limit),
36 _cache_size(cache_size) {
37}
38
39SampleList::~SampleList() {
40 deallocate_samples(_free_list);
41 deallocate_samples(_in_use_list);
42}
43
44ObjectSample* SampleList::last() const {
45 return _in_use_list.head();
46}
47
48ObjectSample* SampleList::first() const {
49 return _in_use_list.tail();
50}
51
52const ObjectSample* SampleList::last_resolved() const {
53 return _last_resolved;
54}
55
56void SampleList::set_last_resolved(const ObjectSample* sample) {
57 assert(last() == sample, "invariant");
58 _last_resolved = sample;
59}
60
61void SampleList::link(ObjectSample* sample) {
62 assert(sample != NULL, "invariant");
63 _in_use_list.prepend(sample);
64}
65
66void SampleList::unlink(ObjectSample* sample) {
67 assert(sample != NULL, "invariant");
68 if (_last_resolved == sample) {
69 _last_resolved = sample->next();
70 }
71 reset(_in_use_list.remove(sample));
72}
73
74ObjectSample* SampleList::reuse(ObjectSample* sample) {
75 assert(sample != NULL, "invariant");
76 unlink(sample);
77 link(sample);
78 return sample;
79}
80
81void SampleList::populate_cache() {
82 if (_free_list.count() < _cache_size) {
83 const size_t cache_delta = _cache_size - _free_list.count();
84 for (size_t i = 0; i < cache_delta; ++i) {
85 ObjectSample* sample = newSample();
86 if (sample != NULL) {
87 _free_list.append(sample);
88 }
89 }
90 }
91}
92
93ObjectSample* SampleList::newSample() const {
94 if (_limit == _allocated) {
95 return NULL;
96 }
97 ++_allocated;
98 return new ObjectSample();
99}
100
101ObjectSample* SampleList::get() {
102 ObjectSample* sample = _free_list.head();
103 if (sample != NULL) {
104 link(_free_list.remove(sample));
105 } else {
106 sample = newSample();
107 if (sample != NULL) {
108 _in_use_list.prepend(sample);
109 }
110 }
111 if (_cache_size > 0 && sample != NULL) {
112 populate_cache();
113 }
114 return sample;
115}
116
117void SampleList::release(ObjectSample* sample) {
118 assert(sample != NULL, "invariant");
119 unlink(sample);
120 _free_list.append(sample);
121}
122
123void SampleList::deallocate_samples(List& list) {
124 if (list.count() > 0) {
125 ObjectSample* sample = list.head();
126 while (sample != NULL) {
127 list.remove(sample);
128 delete sample;
129 sample = list.head();
130 }
131 }
132 assert(list.count() == 0, "invariant");
133}
134
135void SampleList::reset(ObjectSample* sample) {
136 assert(sample != NULL, "invariant");
137 sample->reset();
138}
139
140bool SampleList::is_full() const {
141 return _in_use_list.count() == _limit;
142}
143
144size_t SampleList::count() const {
145 return _in_use_list.count();
146}
147