1/*
2 * Copyright (c) 2017, 2018, 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
44static ObjectSampler* _instance = NULL;
45
46static ObjectSampler& instance() {
47 assert(_instance != NULL, "invariant");
48 return *_instance;
49}
50
51ObjectSampler::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
60ObjectSampler::~ObjectSampler() {
61 delete _priority_queue;
62 _priority_queue = NULL;
63 delete _list;
64 _list = NULL;
65}
66
67bool 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
74bool ObjectSampler::is_created() {
75 return _instance != NULL;
76}
77
78ObjectSampler* ObjectSampler::sampler() {
79 assert(is_created(), "invariant");
80 return _instance;
81}
82
83void 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
92static volatile int _lock = 0;
93
94ObjectSampler* ObjectSampler::acquire() {
95 assert(is_created(), "invariant");
96 while (Atomic::cmpxchg(1, &_lock, 0) == 1) {}
97 return _instance;
98}
99
100void ObjectSampler::release() {
101 assert(is_created(), "invariant");
102 OrderAccess::fence();
103 _lock = 0;
104}
105
106static 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->has_thread_checkpoint()) {
114 JfrCheckpointManager::create_thread_checkpoint(thread);
115 }
116 assert(tl->has_thread_checkpoint(), "invariant");
117 return tl->thread_id();
118}
119
120// Populates the thread local stack frames, but does not add them
121// to the stacktrace repository (...yet, see stacktrace_id() below)
122//
123void ObjectSampler::fill_stacktrace(JfrStackTrace* stacktrace, JavaThread* thread) {
124 assert(stacktrace != NULL, "invariant");
125 assert(thread != NULL, "invariant");
126 if (JfrEventSetting::has_stacktrace(EventOldObjectSample::eventId)) {
127 JfrStackTraceRepository::fill_stacktrace_for(thread, stacktrace, 0);
128 }
129}
130
131// We were successful in acquiring the try lock and have been selected for adding a sample.
132// Go ahead with installing our previously taken stacktrace into the stacktrace repository.
133//
134traceid ObjectSampler::stacktrace_id(const JfrStackTrace* stacktrace, JavaThread* thread) {
135 assert(stacktrace != NULL, "invariant");
136 assert(stacktrace->hash() != 0, "invariant");
137 const traceid stacktrace_id = JfrStackTraceRepository::add(stacktrace, thread);
138 thread->jfr_thread_local()->set_cached_stack_trace_id(stacktrace_id, stacktrace->hash());
139 return stacktrace_id;
140}
141
142void ObjectSampler::sample(HeapWord* obj, size_t allocated, JavaThread* thread) {
143 assert(thread != NULL, "invariant");
144 assert(is_created(), "invariant");
145
146 const traceid thread_id = get_thread_id(thread);
147 if (thread_id == 0) {
148 return;
149 }
150
151 const JfrThreadLocal* const tl = thread->jfr_thread_local();
152 JfrStackTrace stacktrace(tl->stackframes(), tl->stackdepth());
153 fill_stacktrace(&stacktrace, thread);
154
155 // try enter critical section
156 JfrTryLock tryLock(&_lock);
157 if (!tryLock.has_lock()) {
158 log_trace(jfr, oldobject, sampling)("Skipping old object sample due to lock contention");
159 return;
160 }
161
162 instance().add(obj, allocated, thread_id, &stacktrace, thread);
163}
164
165void ObjectSampler::add(HeapWord* obj, size_t allocated, traceid thread_id, JfrStackTrace* stacktrace, JavaThread* thread) {
166 assert(stacktrace != NULL, "invariant");
167 assert(thread_id != 0, "invariant");
168 assert(thread != NULL, "invariant");
169 assert(thread->jfr_thread_local()->has_thread_checkpoint(), "invariant");
170
171 if (_dead_samples) {
172 scavenge();
173 assert(!_dead_samples, "invariant");
174 }
175
176 _total_allocated += allocated;
177 const size_t span = _total_allocated - _priority_queue->total();
178 ObjectSample* sample;
179 if ((size_t)_priority_queue->count() == _size) {
180 assert(_list->count() == _size, "invariant");
181 const ObjectSample* peek = _priority_queue->peek();
182 if (peek->span() > span) {
183 // quick reject, will not fit
184 return;
185 }
186 sample = _list->reuse(_priority_queue->pop());
187 } else {
188 sample = _list->get();
189 }
190
191 assert(sample != NULL, "invariant");
192 sample->set_thread_id(thread_id);
193 sample->set_thread_checkpoint(thread->jfr_thread_local()->thread_checkpoint());
194
195 const unsigned int stacktrace_hash = stacktrace->hash();
196 if (stacktrace_hash != 0) {
197 sample->set_stack_trace_id(stacktrace_id(stacktrace, thread));
198 sample->set_stack_trace_hash(stacktrace_hash);
199 }
200
201 sample->set_span(allocated);
202 sample->set_object((oop)obj);
203 sample->set_allocated(allocated);
204 sample->set_allocation_time(JfrTicks::now());
205 sample->set_heap_used_at_last_gc(Universe::get_heap_used_at_last_gc());
206 _priority_queue->push(sample);
207}
208
209void ObjectSampler::scavenge() {
210 ObjectSample* current = _list->last();
211 while (current != NULL) {
212 ObjectSample* next = current->next();
213 if (current->is_dead()) {
214 remove_dead(current);
215 }
216 current = next;
217 }
218 _dead_samples = false;
219}
220
221void ObjectSampler::remove_dead(ObjectSample* sample) {
222 assert(sample != NULL, "invariant");
223 assert(sample->is_dead(), "invariant");
224 ObjectSample* const previous = sample->prev();
225 // push span on to previous
226 if (previous != NULL) {
227 _priority_queue->remove(previous);
228 previous->add_span(sample->span());
229 _priority_queue->push(previous);
230 }
231 _priority_queue->remove(sample);
232 _list->release(sample);
233}
234
235void ObjectSampler::oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
236 assert(is_created(), "invariant");
237 assert(SafepointSynchronize::is_at_safepoint(), "invariant");
238 ObjectSampler& sampler = instance();
239 ObjectSample* current = sampler._list->last();
240 while (current != NULL) {
241 ObjectSample* next = current->next();
242 if (!current->is_dead()) {
243 if (is_alive->do_object_b(current->object())) {
244 // The weakly referenced object is alive, update pointer
245 f->do_oop(const_cast<oop*>(current->object_addr()));
246 } else {
247 current->set_dead();
248 sampler._dead_samples = true;
249 }
250 }
251 current = next;
252 }
253 sampler._last_sweep = JfrTicks::now();
254}
255
256const ObjectSample* ObjectSampler::last() const {
257 return _list->last();
258}
259
260const ObjectSample* ObjectSampler::first() const {
261 return _list->first();
262}
263
264const ObjectSample* ObjectSampler::last_resolved() const {
265 return _list->last_resolved();
266}
267
268void ObjectSampler::set_last_resolved(const ObjectSample* sample) {
269 _list->set_last_resolved(sample);
270}
271
272int ObjectSampler::item_count() const {
273 return _priority_queue->count();
274}
275
276const ObjectSample* ObjectSampler::item_at(int index) const {
277 return _priority_queue->item_at(index);
278}
279
280ObjectSample* ObjectSampler::item_at(int index) {
281 return const_cast<ObjectSample*>(
282 const_cast<const ObjectSampler*>(this)->item_at(index)
283 );
284}
285
286const JfrTicks& ObjectSampler::last_sweep() const {
287 return _last_sweep;
288}
289