28 #include "memory/allocation.hpp"
29 #include "oops/markOop.hpp"
30 #include "utilities/growableArray.hpp"
31 //
32 // This class will save the original mark oop of a object sample object.
33 // It will then install an "identifier" mark oop to be used for
34 // identification purposes in the search for reference chains.
35 // The destructor will restore each modified oop with its original mark oop.
36 //
37 class ObjectSampleMarker : public StackObj {
38 private:
39 class ObjectSampleMarkWord : public ResourceObj {
40 friend class ObjectSampleMarker;
41 private:
42 oop _obj;
43 markWord _mark_word;
44 ObjectSampleMarkWord(const oop obj,
45 const markWord mark_word) : _obj(obj),
46 _mark_word(mark_word) {}
47 public:
48 ObjectSampleMarkWord() : _obj(NULL), _mark_word(0) {}
49 };
50
51 GrowableArray<ObjectSampleMarkWord>* _store;
52
53 public:
54 ObjectSampleMarker() :
55 _store(new GrowableArray<ObjectSampleMarkWord>(16)) {}
56 ~ObjectSampleMarker() {
57 assert(_store != NULL, "invariant");
58 // restore the saved, original, markWord for sample objects
59 while (_store->is_nonempty()) {
60 ObjectSampleMarkWord sample_oop = _store->pop();
61 sample_oop._obj->set_mark(sample_oop._mark_word);
62 assert(sample_oop._obj->mark() == sample_oop._mark_word, "invariant");
63 }
64 }
65
66 void mark(oop obj) {
67 assert(obj != NULL, "invariant");
68 // save the original markWord
69 _store->push(ObjectSampleMarkWord(obj, obj->mark()));
70 // now we will "poison" the mark word of the sample object
71 // to the intermediate monitor INFLATING state.
72 // This is an "impossible" state during a safepoint,
73 // hence we will use it to quickly identify sample objects
74 // during the reachability search from gc roots.
75 assert(0 == markWord::INFLATING().value(), "invariant");
76 obj->set_mark(markWord::INFLATING());
77 assert(0 == obj->mark().value(), "invariant");
78 }
79 };
80
81 #endif // SHARE_JFR_LEAKPROFILER_CHAINS_OBJECTSAMPLEMARKER_HPP
|
28 #include "memory/allocation.hpp"
29 #include "oops/markOop.hpp"
30 #include "utilities/growableArray.hpp"
31 //
32 // This class will save the original mark oop of a object sample object.
33 // It will then install an "identifier" mark oop to be used for
34 // identification purposes in the search for reference chains.
35 // The destructor will restore each modified oop with its original mark oop.
36 //
37 class ObjectSampleMarker : public StackObj {
38 private:
39 class ObjectSampleMarkWord : public ResourceObj {
40 friend class ObjectSampleMarker;
41 private:
42 oop _obj;
43 markWord _mark_word;
44 ObjectSampleMarkWord(const oop obj,
45 const markWord mark_word) : _obj(obj),
46 _mark_word(mark_word) {}
47 public:
48 ObjectSampleMarkWord() : _obj(NULL), _mark_word(markWord::zero) {}
49 };
50
51 GrowableArray<ObjectSampleMarkWord>* _store;
52
53 public:
54 ObjectSampleMarker() :
55 _store(new GrowableArray<ObjectSampleMarkWord>(16)) {}
56 ~ObjectSampleMarker() {
57 assert(_store != NULL, "invariant");
58 // restore the saved, original, markWord for sample objects
59 while (_store->is_nonempty()) {
60 ObjectSampleMarkWord sample_oop = _store->pop();
61 sample_oop._obj->set_mark(sample_oop._mark_word);
62 assert(sample_oop._obj->mark() == sample_oop._mark_word, "invariant");
63 }
64 }
65
66 void mark(oop obj) {
67 assert(obj != NULL, "invariant");
68 // save the original markWord
69 _store->push(ObjectSampleMarkWord(obj, obj->mark()));
70 // now we will "poison" the mark word of the sample object
71 // to the intermediate monitor INFLATING state.
72 // This is an "impossible" state during a safepoint,
73 // hence we will use it to quickly identify sample objects
74 // during the reachability search from gc roots.
75 assert(NULL == markWord::INFLATING().to_pointer(), "invariant");
76 obj->set_mark(markWord::INFLATING());
77 assert(NULL == obj->mark().to_pointer(), "invariant");
78 }
79 };
80
81 #endif // SHARE_JFR_LEAKPROFILER_CHAINS_OBJECTSAMPLEMARKER_HPP
|