1 /*
2 * Copyright (c) 2005, 2014, 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_GenCollectFull
42 // VM_GenCollectFullConcurrent
43 // VM_ParallelGCSystemGC
44 // VM_CollectForAllocation
45 // VM_GenCollectForAllocation
46 // VM_ParallelGCFailedAllocation
47 // VM_GC_Operation
48 // - implements methods common to all classes in the hierarchy:
49 // prevents multiple gc requests and manages lock on heap;
50 //
51 // VM_GC_HeapInspection
52 // - prints class histogram on SIGBREAK if PrintClassHistogram
53 // is specified; and also the attach "inspectheap" operation
54 //
55 // VM_CollectForAllocation
56 // VM_GenCollectForAllocation
57 // VM_ParallelGCFailedAllocation
58 // - this operation is invoked when allocation is failed;
59 // operation performs garbage collection and tries to
60 // allocate afterwards;
61 //
62 // VM_GenCollectFull
63 // VM_GenCollectFullConcurrent
64 // VM_ParallelGCSystemGC
65 // - these operations preform full collection of heaps of
66 // different kind
67 //
68
69 class VM_GC_Operation: public VM_Operation {
70 protected:
71 BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL)
72 uint _gc_count_before; // gc count before acquiring PLL
73 uint _full_gc_count_before; // full gc count before acquiring PLL
74 bool _full; // whether a "full" collection
75 bool _prologue_succeeded; // whether doit_prologue succeeded
76 GCCause::Cause _gc_cause; // the putative cause for this gc op
77 bool _gc_locked; // will be set if gc was locked
78
79 virtual bool skip_operation() const;
80
81 // java.lang.ref.Reference support
82 void acquire_pending_list_lock();
83 void release_and_notify_pending_list_lock();
84
85 public:
86 VM_GC_Operation(uint gc_count_before,
87 GCCause::Cause _cause,
88 uint full_gc_count_before = 0,
89 bool full = false) {
90 _full = full;
91 _prologue_succeeded = false;
92 _gc_count_before = gc_count_before;
93
94 // A subclass constructor will likely overwrite the following
95 _gc_cause = _cause;
96
97 _gc_locked = false;
98
99 _full_gc_count_before = full_gc_count_before;
100 // In ParallelScavengeHeap::mem_allocate() collections can be
101 // executed within a loop and _all_soft_refs_clear can be set
102 // true after they have been cleared by a collection and another
103 // collection started so that _all_soft_refs_clear can be true
104 // when this collection is started. Don't assert that
105 // _all_soft_refs_clear have to be false here even though
106 // mutators have run. Soft refs will be cleared again in this
107 // collection.
108 }
109 ~VM_GC_Operation() {
110 CollectedHeap* ch = Universe::heap();
111 ch->collector_policy()->set_all_soft_refs_clear(false);
112 }
113
114 // Acquire the reference synchronization lock
115 virtual bool doit_prologue();
116 // Do notifyAll (if needed) and release held lock
117 virtual void doit_epilogue();
118
119 virtual bool allow_nested_vm_operations() const { return true; }
120 bool prologue_succeeded() const { return _prologue_succeeded; }
121
122 void set_gc_locked() { _gc_locked = true; }
123 bool gc_locked() const { return _gc_locked; }
124
125 static void notify_gc_begin(bool full = false);
126 static void notify_gc_end();
127 };
128
129
130 class VM_GC_HeapInspection: public VM_GC_Operation {
131 private:
132 outputStream* _out;
133 bool _full_gc;
134 bool _csv_format; // "comma separated values" format for spreadsheet.
135 bool _print_help;
136 bool _print_class_stats;
137 const char* _columns;
138 public:
139 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
140 VM_GC_Operation(0 /* total collections, dummy, ignored */,
141 GCCause::_heap_inspection /* GC Cause */,
142 0 /* total full collections, dummy, ignored */,
143 request_full_gc) {
144 _out = out;
145 _full_gc = request_full_gc;
146 _csv_format = false;
147 _print_help = false;
148 _print_class_stats = false;
149 _columns = NULL;
150 }
151
152 ~VM_GC_HeapInspection() {}
153 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
154 virtual bool skip_operation() const;
155 virtual bool doit_prologue();
156 virtual void doit();
157 void set_csv_format(bool value) {_csv_format = value;}
158 void set_print_help(bool value) {_print_help = value;}
159 void set_print_class_stats(bool value) {_print_class_stats = value;}
160 void set_columns(const char* value) {_columns = value;}
161 protected:
162 bool collect();
163 };
164
165 class VM_CollectForAllocation : public VM_GC_Operation {
166 protected:
167 size_t _word_size; // Size of object to be allocated (in number of words)
168 HeapWord* _result; // Allocation result (NULL if allocation failed)
169
170 public:
171 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
172
173 HeapWord* result() const {
174 return _result;
175 }
176 };
177
178 class VM_GenCollectForAllocation : public VM_CollectForAllocation {
179 private:
180 bool _tlab; // alloc is of a tlab.
181 public:
182 VM_GenCollectForAllocation(size_t size,
183 bool tlab,
184 uint gc_count_before)
185 : VM_CollectForAllocation(size, gc_count_before, GCCause::_allocation_failure),
186 _tlab(tlab) {}
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 int _max_level;
197 public:
198 VM_GenCollectFull(uint gc_count_before,
199 uint full_gc_count_before,
200 GCCause::Cause gc_cause,
201 int max_level)
202 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */),
203 _max_level(max_level) { }
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 public:
216 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
217 size_t size, Metaspace::MetadataType mdtype,
218 uint gc_count_before,
219 uint full_gc_count_before,
220 GCCause::Cause gc_cause)
221 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true),
222 _loader_data(loader_data), _size(size), _mdtype(mdtype), _result(NULL) {
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, 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_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP