1 /*
2 * Copyright (c) 2005, 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 #ifndef SHARE_VM_GC_SHARED_VMGCOPERATIONS_HPP
26 #define SHARE_VM_GC_SHARED_VMGCOPERATIONS_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/vm_operations.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
71 class VM_GC_Operation: public VM_Operation {
72 protected:
73 BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL)
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 // java.lang.ref.Reference support
84 void acquire_pending_list_lock();
85 void release_and_notify_pending_list_lock();
86
87 public:
88 VM_GC_Operation(uint gc_count_before,
89 GCCause::Cause _cause,
90 uint full_gc_count_before = 0,
91 bool full = false) {
92 _full = full;
93 _prologue_succeeded = false;
94 _gc_count_before = gc_count_before;
95
96 // A subclass constructor will likely overwrite the following
97 _gc_cause = _cause;
98
99 _gc_locked = false;
100
101 _full_gc_count_before = full_gc_count_before;
102 // In ParallelScavengeHeap::mem_allocate() collections can be
103 // executed within a loop and _all_soft_refs_clear can be set
104 // true after they have been cleared by a collection and another
105 // collection started so that _all_soft_refs_clear can be true
106 // when this collection is started. Don't assert that
107 // _all_soft_refs_clear have to be false here even though
108 // mutators have run. Soft refs will be cleared again in this
109 // collection.
110 }
111 ~VM_GC_Operation();
112
113 // Acquire the reference synchronization lock
114 virtual bool doit_prologue();
115 // Do notifyAll (if needed) and release held lock
116 virtual void doit_epilogue();
117
118 virtual bool allow_nested_vm_operations() const { return true; }
119 bool prologue_succeeded() const { return _prologue_succeeded; }
120
121 void set_gc_locked() { _gc_locked = true; }
122 bool gc_locked() const { return _gc_locked; }
123
124 static void notify_gc_begin(bool full = false);
125 static void notify_gc_end();
126 };
127
128
129 class VM_GC_HeapInspection: public VM_GC_Operation {
130 private:
131 outputStream* _out;
132 bool _full_gc;
133 bool _csv_format; // "comma separated values" format for spreadsheet.
134 bool _print_help;
135 bool _print_class_stats;
136 const char* _columns;
137 public:
138 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
139 VM_GC_Operation(0 /* total collections, dummy, ignored */,
140 GCCause::_heap_inspection /* GC Cause */,
141 0 /* total full collections, dummy, ignored */,
142 request_full_gc) {
143 _out = out;
144 _full_gc = request_full_gc;
145 _csv_format = false;
146 _print_help = false;
147 _print_class_stats = false;
148 _columns = NULL;
149 }
150
151 ~VM_GC_HeapInspection() {}
152 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
153 virtual bool skip_operation() const;
154 virtual void doit();
155 void set_csv_format(bool value) {_csv_format = value;}
156 void set_print_help(bool value) {_print_help = value;}
157 void set_print_class_stats(bool value) {_print_class_stats = value;}
158 void set_columns(const char* value) {_columns = value;}
159 protected:
160 bool collect();
161 };
162
163 class VM_CollectForAllocation : public VM_GC_Operation {
164 protected:
165 size_t _word_size; // Size of object to be allocated (in number of words)
166 HeapWord* _result; // Allocation result (NULL if allocation failed)
167
168 public:
169 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
170
171 HeapWord* result() const {
172 return _result;
173 }
174 };
175
176 class VM_GenCollectForAllocation : public VM_CollectForAllocation {
177 private:
178 bool _tlab; // alloc is of a tlab.
179 public:
180 VM_GenCollectForAllocation(size_t word_size,
181 bool tlab,
182 uint gc_count_before)
183 : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
184 _tlab(tlab) {
185 assert(word_size != 0, "An allocation should always be requested with this operation.");
186 }
187 ~VM_GenCollectForAllocation() {}
188 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
189 virtual void doit();
190 };
191
192 // VM operation to invoke a collection of the heap as a
193 // GenCollectedHeap heap.
194 class VM_GenCollectFull: public VM_GC_Operation {
195 private:
196 GenCollectedHeap::GenerationType _max_generation;
197 public:
198 VM_GenCollectFull(uint gc_count_before,
199 uint full_gc_count_before,
200 GCCause::Cause gc_cause,
201 GenCollectedHeap::GenerationType max_generation)
202 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */),
203 _max_generation(max_generation) { }
204 ~VM_GenCollectFull() {}
205 virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
206 virtual void doit();
207 };
208
209 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
210 private:
211 MetaWord* _result;
212 size_t _size; // size of object to be allocated
213 Metaspace::MetadataType _mdtype;
214 ClassLoaderData* _loader_data;
215
216 public:
217 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
218 size_t size,
219 Metaspace::MetadataType mdtype,
220 uint gc_count_before,
221 uint full_gc_count_before,
222 GCCause::Cause gc_cause);
223
224 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
225 virtual void doit();
226 MetaWord* result() const { return _result; }
227
228 bool initiate_concurrent_GC();
229 };
230
231 class SvcGCMarker : public StackObj {
232 private:
233 JvmtiGCMarker _jgcm;
234 public:
235 typedef enum { MINOR, FULL, CONCURRENT, OTHER } reason_type;
236
237 SvcGCMarker(reason_type reason ) {
238 VM_GC_Operation::notify_gc_begin(reason == FULL);
239 }
240
241 ~SvcGCMarker() {
242 VM_GC_Operation::notify_gc_end();
243 }
244 };
245
246 #endif // SHARE_VM_GC_SHARED_VMGCOPERATIONS_HPP
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