Thu, 09 Apr 2015 15:59:26 +0200
8066771: Refactor VM GC operations caused by allocation failure
Reviewed-by: brutisso, jmasa
1 /*
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP
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"
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 //
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
79 virtual bool skip_operation() const;
81 // java.lang.ref.Reference support
82 void acquire_pending_list_lock();
83 void release_and_notify_pending_list_lock();
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;
94 // A subclass constructor will likely overwrite the following
95 _gc_cause = _cause;
97 _gc_locked = false;
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 }
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();
119 virtual bool allow_nested_vm_operations() const { return true; }
120 bool prologue_succeeded() const { return _prologue_succeeded; }
122 void set_gc_locked() { _gc_locked = true; }
123 bool gc_locked() const { return _gc_locked; }
125 static void notify_gc_begin(bool full = false);
126 static void notify_gc_end();
127 };
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 }
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 };
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)
170 public:
171 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause)
172 : VM_GC_Operation(gc_count_before, cause), _result(NULL), _word_size(word_size) {}
174 HeapWord* result() const {
175 return _result;
176 }
177 };
179 class VM_GenCollectForAllocation : public VM_CollectForAllocation {
180 private:
181 bool _tlab; // alloc is of a tlab.
182 public:
183 VM_GenCollectForAllocation(size_t word_size,
184 bool tlab,
185 uint gc_count_before)
186 : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
187 _tlab(tlab) {
188 assert(word_size != 0, "An allocation should always be requested with this operation.");
189 }
190 ~VM_GenCollectForAllocation() {}
191 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
192 virtual void doit();
193 };
195 // VM operation to invoke a collection of the heap as a
196 // GenCollectedHeap heap.
197 class VM_GenCollectFull: public VM_GC_Operation {
198 private:
199 int _max_level;
200 public:
201 VM_GenCollectFull(uint gc_count_before,
202 uint full_gc_count_before,
203 GCCause::Cause gc_cause,
204 int max_level)
205 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */),
206 _max_level(max_level) { }
207 ~VM_GenCollectFull() {}
208 virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
209 virtual void doit();
210 };
212 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
213 private:
214 MetaWord* _result;
215 size_t _size; // size of object to be allocated
216 Metaspace::MetadataType _mdtype;
217 ClassLoaderData* _loader_data;
218 public:
219 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
220 size_t size, Metaspace::MetadataType mdtype,
221 uint gc_count_before,
222 uint full_gc_count_before,
223 GCCause::Cause gc_cause)
224 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true),
225 _loader_data(loader_data), _size(size), _mdtype(mdtype), _result(NULL) {
226 }
227 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
228 virtual void doit();
229 MetaWord* result() const { return _result; }
231 bool initiate_concurrent_GC();
232 };
234 class SvcGCMarker : public StackObj {
235 private:
236 JvmtiGCMarker _jgcm;
237 public:
238 typedef enum { MINOR, FULL, OTHER } reason_type;
240 SvcGCMarker(reason_type reason ) {
241 VM_GC_Operation::notify_gc_begin(reason == FULL);
242 }
244 ~SvcGCMarker() {
245 VM_GC_Operation::notify_gc_end();
246 }
247 };
249 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP