1/*
2 * Copyright (c) 2005, 2019, 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.
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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
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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 "prims/jvmtiExport.hpp"
32#include "runtime/handles.hpp"
33#include "runtime/jniHandles.hpp"
34#include "runtime/synchronizer.hpp"
35#include "runtime/vmOperations.hpp"
36
37// The following class hierarchy represents
38// a set of operations (VM_Operation) related to GC.
39//
40// VM_Operation
41// VM_GC_Operation
42// VM_GC_HeapInspection
43// VM_GenCollectFull
44// VM_GenCollectFullConcurrent
45// VM_ParallelGCSystemGC
46// VM_CollectForAllocation
47// VM_GenCollectForAllocation
48// VM_ParallelGCFailedAllocation
49// VM_GC_Operation
50// - implements methods common to all classes in the hierarchy:
51// prevents multiple gc requests and manages lock on heap;
52//
53// VM_GC_HeapInspection
54// - prints class histogram on SIGBREAK if PrintClassHistogram
55// is specified; and also the attach "inspectheap" operation
56//
57// VM_CollectForAllocation
58// VM_GenCollectForAllocation
59// VM_ParallelGCFailedAllocation
60// - this operation is invoked when allocation is failed;
61// operation performs garbage collection and tries to
62// allocate afterwards;
63//
64// VM_GenCollectFull
65// VM_GenCollectFullConcurrent
66// VM_ParallelGCSystemGC
67// - these operations preform full collection of heaps of
68// different kind
69//
70
71class VM_GC_Operation: public VM_Operation {
72 protected:
73 uint _gc_count_before; // gc count before acquiring PLL
74 uint _full_gc_count_before; // full gc count before acquiring PLL
75 bool _full; // whether a "full" collection
76 bool _prologue_succeeded; // whether doit_prologue succeeded
77 GCCause::Cause _gc_cause; // the putative cause for this gc op
78 bool _gc_locked; // will be set if gc was locked
79
80 virtual bool skip_operation() const;
81
82 public:
83 VM_GC_Operation(uint gc_count_before,
84 GCCause::Cause _cause,
85 uint full_gc_count_before = 0,
86 bool full = false) {
87 _full = full;
88 _prologue_succeeded = false;
89 _gc_count_before = gc_count_before;
90
91 // A subclass constructor will likely overwrite the following
92 _gc_cause = _cause;
93
94 _gc_locked = false;
95
96 _full_gc_count_before = full_gc_count_before;
97 // In ParallelScavengeHeap::mem_allocate() collections can be
98 // executed within a loop and _all_soft_refs_clear can be set
99 // true after they have been cleared by a collection and another
100 // collection started so that _all_soft_refs_clear can be true
101 // when this collection is started. Don't assert that
102 // _all_soft_refs_clear have to be false here even though
103 // mutators have run. Soft refs will be cleared again in this
104 // collection.
105 }
106 ~VM_GC_Operation();
107
108 // Acquire the reference synchronization lock
109 virtual bool doit_prologue();
110 // Do notifyAll (if needed) and release held lock
111 virtual void doit_epilogue();
112
113 virtual bool allow_nested_vm_operations() const { return true; }
114 bool prologue_succeeded() const { return _prologue_succeeded; }
115
116 void set_gc_locked() { _gc_locked = true; }
117 bool gc_locked() const { return _gc_locked; }
118
119 static void notify_gc_begin(bool full = false);
120 static void notify_gc_end();
121};
122
123
124class VM_GC_HeapInspection: public VM_GC_Operation {
125 private:
126 outputStream* _out;
127 bool _full_gc;
128 bool _csv_format; // "comma separated values" format for spreadsheet.
129 bool _print_help;
130 bool _print_class_stats;
131 const char* _columns;
132 public:
133 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
134 VM_GC_Operation(0 /* total collections, dummy, ignored */,
135 GCCause::_heap_inspection /* GC Cause */,
136 0 /* total full collections, dummy, ignored */,
137 request_full_gc) {
138 _out = out;
139 _full_gc = request_full_gc;
140 _csv_format = false;
141 _print_help = false;
142 _print_class_stats = false;
143 _columns = NULL;
144 }
145
146 ~VM_GC_HeapInspection() {}
147 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
148 virtual bool skip_operation() const;
149 virtual void doit();
150 void set_csv_format(bool value) {_csv_format = value;}
151 void set_print_help(bool value) {_print_help = value;}
152 void set_print_class_stats(bool value) {_print_class_stats = value;}
153 void set_columns(const char* value) {_columns = value;}
154 protected:
155 bool collect();
156};
157
158class VM_CollectForAllocation : public VM_GC_Operation {
159 protected:
160 size_t _word_size; // Size of object to be allocated (in number of words)
161 HeapWord* _result; // Allocation result (NULL if allocation failed)
162
163 public:
164 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
165
166 HeapWord* result() const {
167 return _result;
168 }
169};
170
171class VM_GenCollectForAllocation : public VM_CollectForAllocation {
172 private:
173 bool _tlab; // alloc is of a tlab.
174 public:
175 VM_GenCollectForAllocation(size_t word_size,
176 bool tlab,
177 uint gc_count_before)
178 : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
179 _tlab(tlab) {
180 assert(word_size != 0, "An allocation should always be requested with this operation.");
181 }
182 ~VM_GenCollectForAllocation() {}
183 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
184 virtual void doit();
185};
186
187// VM operation to invoke a collection of the heap as a
188// GenCollectedHeap heap.
189class VM_GenCollectFull: public VM_GC_Operation {
190 private:
191 GenCollectedHeap::GenerationType _max_generation;
192 public:
193 VM_GenCollectFull(uint gc_count_before,
194 uint full_gc_count_before,
195 GCCause::Cause gc_cause,
196 GenCollectedHeap::GenerationType max_generation)
197 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */),
198 _max_generation(max_generation) { }
199 ~VM_GenCollectFull() {}
200 virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
201 virtual void doit();
202};
203
204class VM_CollectForMetadataAllocation: public VM_GC_Operation {
205 private:
206 MetaWord* _result;
207 size_t _size; // size of object to be allocated
208 Metaspace::MetadataType _mdtype;
209 ClassLoaderData* _loader_data;
210
211 public:
212 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
213 size_t size,
214 Metaspace::MetadataType mdtype,
215 uint gc_count_before,
216 uint full_gc_count_before,
217 GCCause::Cause gc_cause);
218
219 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
220 virtual void doit();
221 MetaWord* result() const { return _result; }
222
223 bool initiate_concurrent_GC();
224};
225
226class SvcGCMarker : public StackObj {
227 private:
228 JvmtiGCMarker _jgcm;
229 public:
230 typedef enum { MINOR, FULL, CONCURRENT } reason_type;
231
232 SvcGCMarker(reason_type reason ) {
233 VM_GC_Operation::notify_gc_begin(reason == FULL);
234 }
235
236 ~SvcGCMarker() {
237 VM_GC_Operation::notify_gc_end();
238 }
239};
240
241#endif // SHARE_GC_SHARED_GCVMOPERATIONS_HPP
242