Mon, 10 Jan 2011 17:14:53 -0500
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
Summary: Make JvmtiGCMark safe to run non-safepoint and instrument CMS
Reviewed-by: ysr, dcubed
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_GenCollectForAllocation
42 // VM_GenCollectFull
43 // VM_GenCollectFullConcurrent
44 // VM_ParallelGCFailedAllocation
45 // VM_ParallelGCFailedPermanentAllocation
46 // VM_ParallelGCSystemGC
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_GenCollectForAllocation
56 // VM_GenCollectForPermanentAllocation
57 // VM_ParallelGCFailedAllocation
58 // VM_ParallelGCFailedPermanentAllocation
59 // - this operation is invoked when allocation is failed;
60 // operation performs garbage collection and tries to
61 // allocate afterwards;
62 //
63 // VM_GenCollectFull
64 // VM_GenCollectFullConcurrent
65 // VM_ParallelGCSystemGC
66 // - these operations preform full collection of heaps of
67 // different kind
68 //
70 class VM_GC_Operation: public VM_Operation {
71 protected:
72 BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL)
73 unsigned int _gc_count_before; // gc count before acquiring PLL
74 unsigned int _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
80 virtual bool skip_operation() const;
82 // java.lang.ref.Reference support
83 void acquire_pending_list_lock();
84 void release_and_notify_pending_list_lock();
86 public:
87 VM_GC_Operation(unsigned int gc_count_before,
88 unsigned int 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 = GCCause::_no_cause_specified;
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 _need_prologue;
135 public:
136 VM_GC_HeapInspection(outputStream* out, bool request_full_gc,
137 bool need_prologue) :
138 VM_GC_Operation(0 /* total collections, dummy, ignored */,
139 0 /* total full collections, dummy, ignored */,
140 request_full_gc) {
141 _out = out;
142 _full_gc = request_full_gc;
143 _need_prologue = need_prologue;
144 }
146 ~VM_GC_HeapInspection() {}
147 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
148 virtual bool skip_operation() const;
149 virtual bool doit_prologue();
150 virtual void doit();
151 };
154 class VM_GenCollectForAllocation: public VM_GC_Operation {
155 private:
156 HeapWord* _res;
157 size_t _size; // size of object to be allocated.
158 bool _tlab; // alloc is of a tlab.
159 public:
160 VM_GenCollectForAllocation(size_t size,
161 bool tlab,
162 unsigned int gc_count_before)
163 : VM_GC_Operation(gc_count_before),
164 _size(size),
165 _tlab(tlab) {
166 _res = NULL;
167 }
168 ~VM_GenCollectForAllocation() {}
169 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
170 virtual void doit();
171 HeapWord* result() const { return _res; }
172 };
175 // VM operation to invoke a collection of the heap as a
176 // GenCollectedHeap heap.
177 class VM_GenCollectFull: public VM_GC_Operation {
178 private:
179 int _max_level;
180 public:
181 VM_GenCollectFull(unsigned int gc_count_before,
182 unsigned int full_gc_count_before,
183 GCCause::Cause gc_cause,
184 int max_level)
185 : VM_GC_Operation(gc_count_before, full_gc_count_before, true /* full */),
186 _max_level(max_level)
187 { _gc_cause = gc_cause; }
188 ~VM_GenCollectFull() {}
189 virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
190 virtual void doit();
191 };
193 class VM_GenCollectForPermanentAllocation: public VM_GC_Operation {
194 private:
195 HeapWord* _res;
196 size_t _size; // size of object to be allocated
197 public:
198 VM_GenCollectForPermanentAllocation(size_t size,
199 unsigned int gc_count_before,
200 unsigned int full_gc_count_before,
201 GCCause::Cause gc_cause)
202 : VM_GC_Operation(gc_count_before, full_gc_count_before, true),
203 _size(size) {
204 _res = NULL;
205 _gc_cause = gc_cause;
206 }
207 ~VM_GenCollectForPermanentAllocation() {}
208 virtual VMOp_Type type() const { return VMOp_GenCollectForPermanentAllocation; }
209 virtual void doit();
210 HeapWord* result() const { return _res; }
211 };
213 class SvcGCMarker : public StackObj {
214 private:
215 JvmtiGCMarker _jgcm;
216 public:
217 typedef enum { MINOR, FULL, OTHER } reason_type;
219 SvcGCMarker(reason_type reason ) {
220 VM_GC_Operation::notify_gc_begin(reason == FULL);
221 }
223 ~SvcGCMarker() {
224 VM_GC_Operation::notify_gc_end();
225 }
226 };
228 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP