87
88 const u1* JfrBuffer::stable_top() const {
89 const u1* current_top;
90 do {
91 current_top = Atomic::load(&_top);
92 } while (MUTEX_CLAIM == current_top);
93 return current_top;
94 }
95
96 const u1* JfrBuffer::top() const {
97 return _top;
98 }
99
100 void JfrBuffer::set_top(const u1* new_top) {
101 _top = new_top;
102 }
103
104 const u1* JfrBuffer::concurrent_top() const {
105 do {
106 const u1* current_top = stable_top();
107 if (Atomic::cmpxchg(MUTEX_CLAIM, &_top, current_top) == current_top) {
108 return current_top;
109 }
110 } while (true);
111 }
112
113 void JfrBuffer::set_concurrent_top(const u1* new_top) {
114 assert(new_top != MUTEX_CLAIM, "invariant");
115 assert(new_top <= end(), "invariant");
116 assert(new_top >= start(), "invariant");
117 assert(top() == MUTEX_CLAIM, "invariant");
118 OrderAccess::storestore();
119 _top = new_top;
120 }
121
122 size_t JfrBuffer::unflushed_size() const {
123 return pos() - stable_top();
124 }
125
126 void JfrBuffer::acquire(const void* id) {
127 assert(id != NULL, "invariant");
128 const void* current_id;
129 do {
130 current_id = Atomic::load(&_identity);
131 } while (current_id != NULL || Atomic::cmpxchg(id, &_identity, current_id) != current_id);
132 }
133
134 bool JfrBuffer::try_acquire(const void* id) {
135 assert(id != NULL, "invariant");
136 const void* const current_id = Atomic::load(&_identity);
137 return current_id == NULL && Atomic::cmpxchg(id, &_identity, current_id) == current_id;
138 }
139
140 void JfrBuffer::release() {
141 OrderAccess::storestore();
142 _identity = NULL;
143 }
144
145 bool JfrBuffer::acquired_by(const void* id) const {
146 return identity() == id;
147 }
148
149 bool JfrBuffer::acquired_by_self() const {
150 return acquired_by(Thread::current());
151 }
152
153 #ifdef ASSERT
154 static bool validate_to(const JfrBuffer* const to, size_t size) {
155 assert(to != NULL, "invariant");
156 assert(to->acquired_by_self(), "invariant");
157 assert(to->free_size() >= size, "invariant");
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87
88 const u1* JfrBuffer::stable_top() const {
89 const u1* current_top;
90 do {
91 current_top = Atomic::load(&_top);
92 } while (MUTEX_CLAIM == current_top);
93 return current_top;
94 }
95
96 const u1* JfrBuffer::top() const {
97 return _top;
98 }
99
100 void JfrBuffer::set_top(const u1* new_top) {
101 _top = new_top;
102 }
103
104 const u1* JfrBuffer::concurrent_top() const {
105 do {
106 const u1* current_top = stable_top();
107 if (Atomic::cmpxchg(&_top, current_top, MUTEX_CLAIM) == current_top) {
108 return current_top;
109 }
110 } while (true);
111 }
112
113 void JfrBuffer::set_concurrent_top(const u1* new_top) {
114 assert(new_top != MUTEX_CLAIM, "invariant");
115 assert(new_top <= end(), "invariant");
116 assert(new_top >= start(), "invariant");
117 assert(top() == MUTEX_CLAIM, "invariant");
118 OrderAccess::storestore();
119 _top = new_top;
120 }
121
122 size_t JfrBuffer::unflushed_size() const {
123 return pos() - stable_top();
124 }
125
126 void JfrBuffer::acquire(const void* id) {
127 assert(id != NULL, "invariant");
128 const void* current_id;
129 do {
130 current_id = Atomic::load(&_identity);
131 } while (current_id != NULL || Atomic::cmpxchg(&_identity, current_id, id) != current_id);
132 }
133
134 bool JfrBuffer::try_acquire(const void* id) {
135 assert(id != NULL, "invariant");
136 const void* const current_id = Atomic::load(&_identity);
137 return current_id == NULL && Atomic::cmpxchg(&_identity, current_id, id) == current_id;
138 }
139
140 void JfrBuffer::release() {
141 OrderAccess::storestore();
142 _identity = NULL;
143 }
144
145 bool JfrBuffer::acquired_by(const void* id) const {
146 return identity() == id;
147 }
148
149 bool JfrBuffer::acquired_by_self() const {
150 return acquired_by(Thread::current());
151 }
152
153 #ifdef ASSERT
154 static bool validate_to(const JfrBuffer* const to, size_t size) {
155 assert(to != NULL, "invariant");
156 assert(to->acquired_by_self(), "invariant");
157 assert(to->free_size() >= size, "invariant");
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