Wed, 26 Jun 2013 16:58:37 +0200
8013590: NPG: Add a memory pool MXBean for Metaspace
Reviewed-by: jmasa, mgerdin
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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7 * published by the Free Software Foundation.
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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).
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23 */
25 #ifndef SHARE_VM_MEMORY_ITERATOR_HPP
26 #define SHARE_VM_MEMORY_ITERATOR_HPP
28 #include "memory/allocation.hpp"
29 #include "memory/memRegion.hpp"
30 #include "runtime/prefetch.hpp"
31 #include "utilities/top.hpp"
33 // The following classes are C++ `closures` for iterating over objects, roots and spaces
35 class CodeBlob;
36 class nmethod;
37 class ReferenceProcessor;
38 class DataLayout;
39 class KlassClosure;
40 class ClassLoaderData;
42 // Closure provides abortability.
44 class Closure : public StackObj {
45 protected:
46 bool _abort;
47 void set_abort() { _abort = true; }
48 public:
49 Closure() : _abort(false) {}
50 // A subtype can use this mechanism to indicate to some iterator mapping
51 // functions that the iteration should cease.
52 bool abort() { return _abort; }
53 void clear_abort() { _abort = false; }
54 };
56 // OopClosure is used for iterating through references to Java objects.
58 class OopClosure : public Closure {
59 public:
60 virtual void do_oop(oop* o) = 0;
61 virtual void do_oop_v(oop* o) { do_oop(o); }
62 virtual void do_oop(narrowOop* o) = 0;
63 virtual void do_oop_v(narrowOop* o) { do_oop(o); }
64 };
66 // ExtendedOopClosure adds extra code to be run during oop iterations.
67 // This is needed by the GC and is extracted to a separate type to not
68 // pollute the OopClosure interface.
69 class ExtendedOopClosure : public OopClosure {
70 public:
71 ReferenceProcessor* _ref_processor;
72 ExtendedOopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { }
73 ExtendedOopClosure() : OopClosure(), _ref_processor(NULL) { }
75 // If the do_metadata functions return "true",
76 // we invoke the following when running oop_iterate():
77 //
78 // 1) do_klass on the header klass pointer.
79 // 2) do_klass on the klass pointer in the mirrors.
80 // 3) do_class_loader_data on the class loader data in class loaders.
81 //
82 // The virtual (without suffix) and the non-virtual (with _nv suffix) need
83 // to be updated together, or else the devirtualization will break.
84 //
85 // Providing default implementations of the _nv functions unfortunately
86 // removes the compile-time safeness, but reduces the clutter for the
87 // ExtendedOopClosures that don't need to walk the metadata. Currently,
88 // only CMS needs these.
90 virtual bool do_metadata() { return do_metadata_nv(); }
91 bool do_metadata_v() { return do_metadata(); }
92 bool do_metadata_nv() { return false; }
94 virtual void do_klass(Klass* k) { do_klass_nv(k); }
95 void do_klass_v(Klass* k) { do_klass(k); }
96 void do_klass_nv(Klass* k) { ShouldNotReachHere(); }
98 virtual void do_class_loader_data(ClassLoaderData* cld) { ShouldNotReachHere(); }
100 // Controls how prefetching is done for invocations of this closure.
101 Prefetch::style prefetch_style() { // Note that this is non-virtual.
102 return Prefetch::do_none;
103 }
105 // True iff this closure may be safely applied more than once to an oop
106 // location without an intervening "major reset" (like the end of a GC).
107 virtual bool idempotent() { return false; }
108 virtual bool apply_to_weak_ref_discovered_field() { return false; }
109 };
111 // Wrapper closure only used to implement oop_iterate_no_header().
112 class NoHeaderExtendedOopClosure : public ExtendedOopClosure {
113 OopClosure* _wrapped_closure;
114 public:
115 NoHeaderExtendedOopClosure(OopClosure* cl) : _wrapped_closure(cl) {}
116 // Warning: this calls the virtual version do_oop in the the wrapped closure.
117 void do_oop_nv(oop* p) { _wrapped_closure->do_oop(p); }
118 void do_oop_nv(narrowOop* p) { _wrapped_closure->do_oop(p); }
120 void do_oop(oop* p) { assert(false, "Only the _nv versions should be used");
121 _wrapped_closure->do_oop(p); }
122 void do_oop(narrowOop* p) { assert(false, "Only the _nv versions should be used");
123 _wrapped_closure->do_oop(p);}
124 };
126 class KlassClosure : public Closure {
127 public:
128 virtual void do_klass(Klass* k) = 0;
129 };
131 class KlassToOopClosure : public KlassClosure {
132 OopClosure* _oop_closure;
133 public:
134 KlassToOopClosure(OopClosure* oop_closure) : _oop_closure(oop_closure) {}
135 virtual void do_klass(Klass* k);
136 };
138 class CLDToOopClosure {
139 OopClosure* _oop_closure;
140 KlassToOopClosure _klass_closure;
141 bool _must_claim_cld;
143 public:
144 CLDToOopClosure(OopClosure* oop_closure, bool must_claim_cld = true) :
145 _oop_closure(oop_closure),
146 _klass_closure(oop_closure),
147 _must_claim_cld(must_claim_cld) {}
149 void do_cld(ClassLoaderData* cld);
150 };
152 // ObjectClosure is used for iterating through an object space
154 class ObjectClosure : public Closure {
155 public:
156 // Called for each object.
157 virtual void do_object(oop obj) = 0;
158 };
161 class BoolObjectClosure : public Closure {
162 public:
163 virtual bool do_object_b(oop obj) = 0;
164 };
166 // Applies an oop closure to all ref fields in objects iterated over in an
167 // object iteration.
168 class ObjectToOopClosure: public ObjectClosure {
169 ExtendedOopClosure* _cl;
170 public:
171 void do_object(oop obj);
172 ObjectToOopClosure(ExtendedOopClosure* cl) : _cl(cl) {}
173 };
175 // A version of ObjectClosure with "memory" (see _previous_address below)
176 class UpwardsObjectClosure: public BoolObjectClosure {
177 HeapWord* _previous_address;
178 public:
179 UpwardsObjectClosure() : _previous_address(NULL) { }
180 void set_previous(HeapWord* addr) { _previous_address = addr; }
181 HeapWord* previous() { return _previous_address; }
182 // A return value of "true" can be used by the caller to decide
183 // if this object's end should *NOT* be recorded in
184 // _previous_address above.
185 virtual bool do_object_bm(oop obj, MemRegion mr) = 0;
186 };
188 // A version of ObjectClosure that is expected to be robust
189 // in the face of possibly uninitialized objects.
190 class ObjectClosureCareful : public ObjectClosure {
191 public:
192 virtual size_t do_object_careful_m(oop p, MemRegion mr) = 0;
193 virtual size_t do_object_careful(oop p) = 0;
194 };
196 // The following are used in CompactibleFreeListSpace and
197 // ConcurrentMarkSweepGeneration.
199 // Blk closure (abstract class)
200 class BlkClosure : public StackObj {
201 public:
202 virtual size_t do_blk(HeapWord* addr) = 0;
203 };
205 // A version of BlkClosure that is expected to be robust
206 // in the face of possibly uninitialized objects.
207 class BlkClosureCareful : public BlkClosure {
208 public:
209 size_t do_blk(HeapWord* addr) {
210 guarantee(false, "call do_blk_careful instead");
211 return 0;
212 }
213 virtual size_t do_blk_careful(HeapWord* addr) = 0;
214 };
216 // SpaceClosure is used for iterating over spaces
218 class Space;
219 class CompactibleSpace;
221 class SpaceClosure : public StackObj {
222 public:
223 // Called for each space
224 virtual void do_space(Space* s) = 0;
225 };
227 class CompactibleSpaceClosure : public StackObj {
228 public:
229 // Called for each compactible space
230 virtual void do_space(CompactibleSpace* s) = 0;
231 };
234 // CodeBlobClosure is used for iterating through code blobs
235 // in the code cache or on thread stacks
237 class CodeBlobClosure : public Closure {
238 public:
239 // Called for each code blob.
240 virtual void do_code_blob(CodeBlob* cb) = 0;
241 };
244 class MarkingCodeBlobClosure : public CodeBlobClosure {
245 public:
246 // Called for each code blob, but at most once per unique blob.
247 virtual void do_newly_marked_nmethod(nmethod* nm) = 0;
249 virtual void do_code_blob(CodeBlob* cb);
250 // = { if (!nmethod(cb)->test_set_oops_do_mark()) do_newly_marked_nmethod(cb); }
252 class MarkScope : public StackObj {
253 protected:
254 bool _active;
255 public:
256 MarkScope(bool activate = true);
257 // = { if (active) nmethod::oops_do_marking_prologue(); }
258 ~MarkScope();
259 // = { if (active) nmethod::oops_do_marking_epilogue(); }
260 };
261 };
264 // Applies an oop closure to all ref fields in code blobs
265 // iterated over in an object iteration.
266 class CodeBlobToOopClosure: public MarkingCodeBlobClosure {
267 OopClosure* _cl;
268 bool _do_marking;
269 public:
270 virtual void do_newly_marked_nmethod(nmethod* cb);
271 // = { cb->oops_do(_cl); }
272 virtual void do_code_blob(CodeBlob* cb);
273 // = { if (_do_marking) super::do_code_blob(cb); else cb->oops_do(_cl); }
274 CodeBlobToOopClosure(OopClosure* cl, bool do_marking)
275 : _cl(cl), _do_marking(do_marking) {}
276 };
280 // MonitorClosure is used for iterating over monitors in the monitors cache
282 class ObjectMonitor;
284 class MonitorClosure : public StackObj {
285 public:
286 // called for each monitor in cache
287 virtual void do_monitor(ObjectMonitor* m) = 0;
288 };
290 // A closure that is applied without any arguments.
291 class VoidClosure : public StackObj {
292 public:
293 // I would have liked to declare this a pure virtual, but that breaks
294 // in mysterious ways, for unknown reasons.
295 virtual void do_void();
296 };
299 // YieldClosure is intended for use by iteration loops
300 // to incrementalize their work, allowing interleaving
301 // of an interruptable task so as to allow other
302 // threads to run (which may not otherwise be able to access
303 // exclusive resources, for instance). Additionally, the
304 // closure also allows for aborting an ongoing iteration
305 // by means of checking the return value from the polling
306 // call.
307 class YieldClosure : public StackObj {
308 public:
309 virtual bool should_return() = 0;
310 };
312 // Abstract closure for serializing data (read or write).
314 class SerializeClosure : public Closure {
315 public:
316 // Return bool indicating whether closure implements read or write.
317 virtual bool reading() const = 0;
319 // Read/write the void pointer pointed to by p.
320 virtual void do_ptr(void** p) = 0;
322 // Read/write the region specified.
323 virtual void do_region(u_char* start, size_t size) = 0;
325 // Check/write the tag. If reading, then compare the tag against
326 // the passed in value and fail is they don't match. This allows
327 // for verification that sections of the serialized data are of the
328 // correct length.
329 virtual void do_tag(int tag) = 0;
330 };
332 class SymbolClosure : public StackObj {
333 public:
334 virtual void do_symbol(Symbol**) = 0;
336 // Clear LSB in symbol address; it can be set by CPSlot.
337 static Symbol* load_symbol(Symbol** p) {
338 return (Symbol*)(intptr_t(*p) & ~1);
339 }
341 // Store symbol, adjusting new pointer if the original pointer was adjusted
342 // (symbol references in constant pool slots have their LSB set to 1).
343 static void store_symbol(Symbol** p, Symbol* sym) {
344 *p = (Symbol*)(intptr_t(sym) | (intptr_t(*p) & 1));
345 }
346 };
348 #endif // SHARE_VM_MEMORY_ITERATOR_HPP