1 /* 2 * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 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). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "jfr/jfrEvents.hpp" 27 #include "jfr/leakprofiler/sampling/objectSample.hpp" 28 #include "jfr/leakprofiler/sampling/objectSampler.hpp" 29 #include "jfr/leakprofiler/sampling/sampleList.hpp" 30 #include "jfr/leakprofiler/sampling/samplePriorityQueue.hpp" 31 #include "jfr/recorder/jfrEventSetting.inline.hpp" 32 #include "jfr/recorder/checkpoint/jfrCheckpointManager.hpp" 33 #include "jfr/recorder/stacktrace/jfrStackTraceRepository.hpp" 34 #include "jfr/support/jfrThreadLocal.hpp" 35 #include "jfr/utilities/jfrTryLock.hpp" 36 #include "logging/log.hpp" 37 #include "memory/universe.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "runtime/atomic.hpp" 40 #include "runtime/orderAccess.hpp" 41 #include "runtime/safepoint.hpp" 42 #include "runtime/thread.hpp" 43 44 static ObjectSampler* _instance = NULL; 45 46 static ObjectSampler& instance() { 47 assert(_instance != NULL, "invariant"); 48 return *_instance; 49 } 50 51 ObjectSampler::ObjectSampler(size_t size) : 52 _priority_queue(new SamplePriorityQueue(size)), 53 _list(new SampleList(size)), 54 _last_sweep(JfrTicks::now()), 55 _total_allocated(0), 56 _threshold(0), 57 _size(size), 58 _dead_samples(false) {} 59 60 ObjectSampler::~ObjectSampler() { 61 delete _priority_queue; 62 _priority_queue = NULL; 63 delete _list; 64 _list = NULL; 65 } 66 67 bool ObjectSampler::create(size_t size) { 68 assert(SafepointSynchronize::is_at_safepoint(), "invariant"); 69 assert(_instance == NULL, "invariant"); 70 _instance = new ObjectSampler(size); 71 return _instance != NULL; 72 } 73 74 bool ObjectSampler::is_created() { 75 return _instance != NULL; 76 } 77 78 ObjectSampler* ObjectSampler::sampler() { 79 assert(is_created(), "invariant"); 80 return _instance; 81 } 82 83 void ObjectSampler::destroy() { 84 assert(SafepointSynchronize::is_at_safepoint(), "invariant"); 85 if (_instance != NULL) { 86 ObjectSampler* const sampler = _instance; 87 _instance = NULL; 88 delete sampler; 89 } 90 } 91 92 static volatile int _lock = 0; 93 94 ObjectSampler* ObjectSampler::acquire() { 95 assert(is_created(), "invariant"); 96 while (Atomic::cmpxchg(&_lock, 0, 1) == 1) {} 97 return _instance; 98 } 99 100 void ObjectSampler::release() { 101 assert(is_created(), "invariant"); 102 OrderAccess::fence(); 103 _lock = 0; 104 } 105 106 static traceid get_thread_id(JavaThread* thread) { 107 assert(thread != NULL, "invariant"); 108 if (thread->threadObj() == NULL) { 109 return 0; 110 } 111 const JfrThreadLocal* const tl = thread->jfr_thread_local(); 112 assert(tl != NULL, "invariant"); 113 if (tl->is_excluded()) { 114 return 0; 115 } 116 if (!tl->has_thread_blob()) { 117 JfrCheckpointManager::create_thread_blob(thread); 118 } 119 assert(tl->has_thread_blob(), "invariant"); 120 return tl->thread_id(); 121 } 122 123 static void record_stacktrace(JavaThread* thread) { 124 assert(thread != NULL, "invariant"); 125 if (JfrEventSetting::has_stacktrace(EventOldObjectSample::eventId)) { 126 JfrStackTraceRepository::record_and_cache(thread); 127 } 128 } 129 130 void ObjectSampler::sample(HeapWord* obj, size_t allocated, JavaThread* thread) { 131 assert(thread != NULL, "invariant"); 132 assert(is_created(), "invariant"); 133 const traceid thread_id = get_thread_id(thread); 134 if (thread_id == 0) { 135 return; 136 } 137 record_stacktrace(thread); 138 // try enter critical section 139 JfrTryLock tryLock(&_lock); 140 if (!tryLock.has_lock()) { 141 log_trace(jfr, oldobject, sampling)("Skipping old object sample due to lock contention"); 142 return; 143 } 144 instance().add(obj, allocated, thread_id, thread); 145 } 146 147 void ObjectSampler::add(HeapWord* obj, size_t allocated, traceid thread_id, JavaThread* thread) { 148 assert(obj != NULL, "invariant"); 149 assert(thread_id != 0, "invariant"); 150 assert(thread != NULL, "invariant"); 151 assert(thread->jfr_thread_local()->has_thread_blob(), "invariant"); 152 153 if (_dead_samples) { 154 scavenge(); 155 assert(!_dead_samples, "invariant"); 156 } 157 158 _total_allocated += allocated; 159 const size_t span = _total_allocated - _priority_queue->total(); 160 ObjectSample* sample; 161 if ((size_t)_priority_queue->count() == _size) { 162 assert(_list->count() == _size, "invariant"); 163 const ObjectSample* peek = _priority_queue->peek(); 164 if (peek->span() > span) { 165 // quick reject, will not fit 166 return; 167 } 168 sample = _list->reuse(_priority_queue->pop()); 169 } else { 170 sample = _list->get(); 171 } 172 173 assert(sample != NULL, "invariant"); 174 sample->set_thread_id(thread_id); 175 176 const JfrThreadLocal* const tl = thread->jfr_thread_local(); 177 sample->set_thread(tl->thread_blob()); 178 179 const unsigned int stacktrace_hash = tl->cached_stack_trace_hash(); 180 if (stacktrace_hash != 0) { 181 sample->set_stack_trace_id(tl->cached_stack_trace_id()); 182 sample->set_stack_trace_hash(stacktrace_hash); 183 } 184 185 sample->set_span(allocated); 186 sample->set_object((oop)obj); 187 sample->set_allocated(allocated); 188 sample->set_allocation_time(JfrTicks::now()); 189 sample->set_heap_used_at_last_gc(Universe::get_heap_used_at_last_gc()); 190 _priority_queue->push(sample); 191 } 192 193 void ObjectSampler::scavenge() { 194 ObjectSample* current = _list->last(); 195 while (current != NULL) { 196 ObjectSample* next = current->next(); 197 if (current->is_dead()) { 198 remove_dead(current); 199 } 200 current = next; 201 } 202 _dead_samples = false; 203 } 204 205 void ObjectSampler::remove_dead(ObjectSample* sample) { 206 assert(sample != NULL, "invariant"); 207 assert(sample->is_dead(), "invariant"); 208 ObjectSample* const previous = sample->prev(); 209 // push span on to previous 210 if (previous != NULL) { 211 _priority_queue->remove(previous); 212 previous->add_span(sample->span()); 213 _priority_queue->push(previous); 214 } 215 _priority_queue->remove(sample); 216 _list->release(sample); 217 } 218 219 void ObjectSampler::oops_do(BoolObjectClosure* is_alive, OopClosure* f) { 220 assert(is_created(), "invariant"); 221 assert(SafepointSynchronize::is_at_safepoint(), "invariant"); 222 ObjectSampler& sampler = instance(); 223 ObjectSample* current = sampler._list->last(); 224 while (current != NULL) { 225 ObjectSample* next = current->next(); 226 if (!current->is_dead()) { 227 if (is_alive->do_object_b(current->object())) { 228 // The weakly referenced object is alive, update pointer 229 f->do_oop(const_cast<oop*>(current->object_addr())); 230 } else { 231 current->set_dead(); 232 sampler._dead_samples = true; 233 } 234 } 235 current = next; 236 } 237 sampler._last_sweep = JfrTicks::now(); 238 } 239 240 ObjectSample* ObjectSampler::last() const { 241 return _list->last(); 242 } 243 244 const ObjectSample* ObjectSampler::first() const { 245 return _list->first(); 246 } 247 248 const ObjectSample* ObjectSampler::last_resolved() const { 249 return _list->last_resolved(); 250 } 251 252 void ObjectSampler::set_last_resolved(const ObjectSample* sample) { 253 _list->set_last_resolved(sample); 254 } 255 256 int ObjectSampler::item_count() const { 257 return _priority_queue->count(); 258 } 259 260 const ObjectSample* ObjectSampler::item_at(int index) const { 261 return _priority_queue->item_at(index); 262 } 263 264 ObjectSample* ObjectSampler::item_at(int index) { 265 return const_cast<ObjectSample*>( 266 const_cast<const ObjectSampler*>(this)->item_at(index) 267 ); 268 } 269 270 const JfrTicks& ObjectSampler::last_sweep() const { 271 return _last_sweep; 272 }