1 /*
2 * Copyright (c) 2005, 2013, 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_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP
27
28 #include "memory/heapInspection.hpp"
29 #include "runtime/handles.hpp"
30 #include "runtime/jniHandles.hpp"
31 #include "runtime/synchronizer.hpp"
32 #include "runtime/vm_operations.hpp"
33 #include "prims/jvmtiExport.hpp"
34
35 // The following class hierarchy represents
36 // a set of operations (VM_Operation) related to GC.
37 //
38 // VM_Operation
39 // VM_GC_Operation
40 // VM_GC_HeapInspection
41 // VM_GenCollectForAllocation
42 // VM_GenCollectFull
43 // VM_GenCollectFullConcurrent
44 // VM_ParallelGCFailedAllocation
45 // VM_ParallelGCSystemGC
46 // VM_GC_Operation
47 // - implements methods common to all classes in the hierarchy:
48 // prevents multiple gc requests and manages lock on heap;
49 //
50 // VM_GC_HeapInspection
51 // - prints class histogram on SIGBREAK if PrintClassHistogram
52 // is specified; and also the attach "inspectheap" operation
53 //
54 // VM_GenCollectForAllocation
55 // VM_ParallelGCFailedAllocation
56 // - this operation is invoked when allocation is failed;
57 // operation performs garbage collection and tries to
58 // allocate afterwards;
59 //
60 // VM_GenCollectFull
61 // VM_GenCollectFullConcurrent
62 // VM_ParallelGCSystemGC
63 // - these operations preform full collection of heaps of
64 // different kind
65 //
66
67 class VM_GC_Operation: public VM_Operation {
68 protected:
69 BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL)
70 unsigned int _gc_count_before; // gc count before acquiring PLL
71 unsigned int _full_gc_count_before; // full gc count before acquiring PLL
72 bool _full; // whether a "full" collection
73 bool _prologue_succeeded; // whether doit_prologue succeeded
74 GCCause::Cause _gc_cause; // the putative cause for this gc op
75 bool _gc_locked; // will be set if gc was locked
76
77 virtual bool skip_operation() const;
78
79 // java.lang.ref.Reference support
80 void acquire_pending_list_lock();
81 void release_and_notify_pending_list_lock();
82
83 public:
84 VM_GC_Operation(unsigned int gc_count_before,
85 GCCause::Cause _cause,
86 unsigned int 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 CollectedHeap* ch = Universe::heap();
109 ch->collector_policy()->set_all_soft_refs_clear(false);
110 }
111
112 // Acquire the reference synchronization lock
113 virtual bool doit_prologue();
114 // Do notifyAll (if needed) and release held lock
115 virtual void doit_epilogue();
116
117 virtual bool allow_nested_vm_operations() const { return true; }
118 bool prologue_succeeded() const { return _prologue_succeeded; }
119
120 void set_gc_locked() { _gc_locked = true; }
121 bool gc_locked() const { return _gc_locked; }
122
123 static void notify_gc_begin(bool full = false);
124 static void notify_gc_end();
125 };
126
127
128 class VM_GC_HeapInspection: public VM_GC_Operation {
129 private:
130 outputStream* _out;
131 bool _full_gc;
132 bool _csv_format; // "comma separated values" format for spreadsheet.
133 bool _print_help;
134 bool _print_class_stats;
135 const char* _columns;
136 public:
137 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
138 VM_GC_Operation(0 /* total collections, dummy, ignored */,
139 GCCause::_heap_inspection /* GC Cause */,
140 0 /* total full collections, dummy, ignored */,
141 request_full_gc) {
142 _out = out;
143 _full_gc = request_full_gc;
144 _csv_format = false;
145 _print_help = false;
146 _print_class_stats = false;
147 _columns = NULL;
148 }
149
150 ~VM_GC_HeapInspection() {}
151 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
152 virtual bool skip_operation() const;
153 virtual bool doit_prologue();
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
164 class VM_GenCollectForAllocation: public VM_GC_Operation {
165 private:
166 HeapWord* _res;
167 size_t _size; // size of object to be allocated.
168 bool _tlab; // alloc is of a tlab.
169 public:
170 VM_GenCollectForAllocation(size_t size,
171 bool tlab,
172 unsigned int gc_count_before)
173 : VM_GC_Operation(gc_count_before, GCCause::_allocation_failure),
174 _size(size),
175 _tlab(tlab) {
176 _res = NULL;
177 }
178 ~VM_GenCollectForAllocation() {}
179 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
180 virtual void doit();
181 HeapWord* result() const { return _res; }
182 };
183
184
185 // VM operation to invoke a collection of the heap as a
186 // GenCollectedHeap heap.
187 class VM_GenCollectFull: public VM_GC_Operation {
188 private:
189 int _max_level;
190 public:
191 VM_GenCollectFull(unsigned int gc_count_before,
192 unsigned int full_gc_count_before,
193 GCCause::Cause gc_cause,
194 int max_level)
195 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */),
196 _max_level(max_level) { }
197 ~VM_GenCollectFull() {}
198 virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
199 virtual void doit();
200 };
201
202 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
203 private:
204 MetaWord* _result;
205 size_t _size; // size of object to be allocated
206 Metaspace::MetadataType _mdtype;
207 ClassLoaderData* _loader_data;
208 public:
209 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
210 size_t size, Metaspace::MetadataType mdtype,
211 unsigned int gc_count_before,
212 unsigned int full_gc_count_before,
213 GCCause::Cause gc_cause)
214 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true),
215 _loader_data(loader_data), _size(size), _mdtype(mdtype), _result(NULL) {
216 }
217 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
218 virtual void doit();
219 MetaWord* result() const { return _result; }
220
221 bool initiate_concurrent_GC();
222 };
223
224 class SvcGCMarker : public StackObj {
225 private:
226 JvmtiGCMarker _jgcm;
227 public:
228 typedef enum { MINOR, FULL, OTHER } reason_type;
229
230 SvcGCMarker(reason_type reason ) {
231 VM_GC_Operation::notify_gc_begin(reason == FULL);
232 }
233
234 ~SvcGCMarker() {
235 VM_GC_Operation::notify_gc_end();
236 }
237 };
238
239 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP