1/*
2 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2019, Google and/or its affiliates. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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24 */
25
26#ifndef SHARE_GC_SHARED_GCOVERHEADCHECKER_HPP
27#define SHARE_GC_SHARED_GCOVERHEADCHECKER_HPP
28
29#include "memory/allocation.hpp"
30#include "gc/shared/gcCause.hpp"
31
32class SoftRefPolicy;
33
34class GCOverheadTester: public StackObj {
35public:
36 virtual bool is_exceeded() = 0;
37};
38
39class GCOverheadChecker: public CHeapObj<mtGC> {
40 // This is a hint for the heap: we've detected that GC times
41 // are taking longer than GCTimeLimit allows.
42 bool _gc_overhead_limit_exceeded;
43 // Use for diagnostics only. If UseGCOverheadLimit is false,
44 // this variable is still set.
45 bool _print_gc_overhead_limit_would_be_exceeded;
46 // Count of consecutive GC that have exceeded the
47 // GC time limit criterion
48 uint _gc_overhead_limit_count;
49 // This flag signals that GCTimeLimit is being exceeded
50 // but may not have done so for the required number of consecutive
51 // collections
52
53public:
54 GCOverheadChecker();
55
56 // This is a hint for the heap: we've detected that gc times
57 // are taking longer than GCTimeLimit allows.
58 // Most heaps will choose to throw an OutOfMemoryError when
59 // this occurs but it is up to the heap to request this information
60 // of the policy
61 bool gc_overhead_limit_exceeded() {
62 return _gc_overhead_limit_exceeded;
63 }
64 void set_gc_overhead_limit_exceeded(bool v) {
65 _gc_overhead_limit_exceeded = v;
66 }
67
68 // Tests conditions indicate the GC overhead limit is being approached.
69 bool gc_overhead_limit_near() {
70 return _gc_overhead_limit_count >= (GCOverheadLimitThreshold - 1);
71 }
72 void reset_gc_overhead_limit_count() {
73 _gc_overhead_limit_count = 0;
74 }
75
76 // Check the conditions for an out-of-memory due to excessive GC time.
77 // Set _gc_overhead_limit_exceeded if all the conditions have been met.
78 void check_gc_overhead_limit(GCOverheadTester* time_overhead,
79 GCOverheadTester* space_overhead,
80 bool is_full_gc,
81 GCCause::Cause gc_cause,
82 SoftRefPolicy* soft_ref_policy);
83};
84
85#endif // SHARE_GC_SHARED_GCOVERHEADCHECKER_HPP
86