rev 60538 : imported patch jep387-all.patch
1 /*
2 * Copyright (c) 2005, 2020, 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_GC_SHARED_GCVMOPERATIONS_HPP
26 #define SHARE_GC_SHARED_GCVMOPERATIONS_HPP
27
28 #include "gc/shared/collectedHeap.hpp"
29 #include "gc/shared/genCollectedHeap.hpp"
30 #include "memory/heapInspection.hpp"
31 #include "memory/metaspace.hpp"
32 #include "prims/jvmtiExport.hpp"
33 #include "runtime/handles.hpp"
34 #include "runtime/jniHandles.hpp"
35 #include "runtime/synchronizer.hpp"
36 #include "runtime/vmOperations.hpp"
37
38 // The following class hierarchy represents
39 // a set of operations (VM_Operation) related to GC.
40 //
41 // VM_Operation
42 // VM_GC_Operation
43 // VM_GC_HeapInspection
44 // VM_GenCollectFull
45 // VM_GenCollectFullConcurrent
46 // VM_ParallelGCSystemGC
47 // VM_CollectForAllocation
48 // VM_GenCollectForAllocation
49 // VM_ParallelGCFailedAllocation
50 // VM_GC_Operation
51 // - implements methods common to all classes in the hierarchy:
52 // prevents multiple gc requests and manages lock on heap;
53 //
54 // VM_GC_HeapInspection
55 // - prints class histogram on SIGBREAK if PrintClassHistogram
56 // is specified; and also the attach "inspectheap" operation
57 //
58 // VM_CollectForAllocation
59 // VM_GenCollectForAllocation
60 // VM_ParallelGCFailedAllocation
61 // - this operation is invoked when allocation is failed;
62 // operation performs garbage collection and tries to
63 // allocate afterwards;
64 //
65 // VM_GenCollectFull
66 // VM_GenCollectFullConcurrent
67 // VM_ParallelGCSystemGC
68 // - these operations preform full collection of heaps of
69 // different kind
70 //
71
72 class VM_GC_Operation: public VM_Operation {
73 protected:
74 uint _gc_count_before; // gc count before acquiring PLL
75 uint _full_gc_count_before; // full gc count before acquiring PLL
76 bool _full; // whether a "full" collection
77 bool _prologue_succeeded; // whether doit_prologue succeeded
78 GCCause::Cause _gc_cause; // the putative cause for this gc op
79 bool _gc_locked; // will be set if gc was locked
80
81 virtual bool skip_operation() const;
82
83 public:
84 VM_GC_Operation(uint gc_count_before,
85 GCCause::Cause _cause,
86 uint full_gc_count_before = 0,
87 bool full = false) {
88 _full = full;
89 _prologue_succeeded = false;
90 _gc_count_before = gc_count_before;
91
92 // A subclass constructor will likely overwrite the following
93 _gc_cause = _cause;
94
95 _gc_locked = false;
96
97 _full_gc_count_before = full_gc_count_before;
98 // In ParallelScavengeHeap::mem_allocate() collections can be
99 // executed within a loop and _all_soft_refs_clear can be set
100 // true after they have been cleared by a collection and another
101 // collection started so that _all_soft_refs_clear can be true
102 // when this collection is started. Don't assert that
103 // _all_soft_refs_clear have to be false here even though
104 // mutators have run. Soft refs will be cleared again in this
105 // collection.
106 }
107 ~VM_GC_Operation();
108
109 // Acquire the reference synchronization lock
110 virtual bool doit_prologue();
111 // Do notifyAll (if needed) and release held lock
112 virtual void doit_epilogue();
113
114 virtual bool allow_nested_vm_operations() const { return true; }
115 bool prologue_succeeded() const { return _prologue_succeeded; }
116
117 void set_gc_locked() { _gc_locked = true; }
118 bool gc_locked() const { return _gc_locked; }
119
120 static void notify_gc_begin(bool full = false);
121 static void notify_gc_end();
122 };
123
124
125 class VM_GC_HeapInspection: public VM_GC_Operation {
126 private:
127 outputStream* _out;
128 bool _full_gc;
129 public:
130 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
131 VM_GC_Operation(0 /* total collections, dummy, ignored */,
132 GCCause::_heap_inspection /* GC Cause */,
133 0 /* total full collections, dummy, ignored */,
134 request_full_gc), _out(out), _full_gc(request_full_gc) {}
135
136 ~VM_GC_HeapInspection() {}
137 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
138 virtual bool skip_operation() const;
139 virtual void doit();
140 protected:
141 bool collect();
142 };
143
144 class VM_CollectForAllocation : public VM_GC_Operation {
145 protected:
146 size_t _word_size; // Size of object to be allocated (in number of words)
147 HeapWord* _result; // Allocation result (NULL if allocation failed)
148
149 public:
150 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
151
152 HeapWord* result() const {
153 return _result;
154 }
155 };
156
157 class VM_GenCollectForAllocation : public VM_CollectForAllocation {
158 private:
159 bool _tlab; // alloc is of a tlab.
160 public:
161 VM_GenCollectForAllocation(size_t word_size,
162 bool tlab,
163 uint gc_count_before)
164 : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
165 _tlab(tlab) {
166 assert(word_size != 0, "An allocation should always be requested with this operation.");
167 }
168 ~VM_GenCollectForAllocation() {}
169 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
170 virtual void doit();
171 };
172
173 // VM operation to invoke a collection of the heap as a
174 // GenCollectedHeap heap.
175 class VM_GenCollectFull: public VM_GC_Operation {
176 private:
177 GenCollectedHeap::GenerationType _max_generation;
178 public:
179 VM_GenCollectFull(uint gc_count_before,
180 uint full_gc_count_before,
181 GCCause::Cause gc_cause,
182 GenCollectedHeap::GenerationType max_generation)
183 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before,
184 max_generation != GenCollectedHeap::YoungGen /* full */),
185 _max_generation(max_generation) { }
186 ~VM_GenCollectFull() {}
187 virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
188 virtual void doit();
189 };
190
191 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
192 private:
193 MetaWord* _result;
194 size_t _size; // size of object to be allocated
195 Metaspace::MetadataType _mdtype;
196 ClassLoaderData* _loader_data;
197
198 public:
199 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
200 size_t size,
201 Metaspace::MetadataType mdtype,
202 uint gc_count_before,
203 uint full_gc_count_before,
204 GCCause::Cause gc_cause);
205
206 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
207 virtual void doit();
208 MetaWord* result() const { return _result; }
209
210 bool initiate_concurrent_GC();
211 };
212
213 class SvcGCMarker : public StackObj {
214 private:
215 JvmtiGCMarker _jgcm;
216 public:
217 typedef enum { MINOR, FULL, CONCURRENT } reason_type;
218
219 SvcGCMarker(reason_type reason ) {
220 VM_GC_Operation::notify_gc_begin(reason == FULL);
221 }
222
223 ~SvcGCMarker() {
224 VM_GC_Operation::notify_gc_end();
225 }
226 };
227
228 #endif // SHARE_GC_SHARED_GCVMOPERATIONS_HPP
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