1 /*
  2  * Copyright (c) 2015, 2020, 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 #include "precompiled.hpp"
 25 #include "classfile/classLoaderDataGraph.hpp"
 26 #include "classfile/stringTable.hpp"
 27 #include "code/codeCache.hpp"
 28 #include "compiler/oopMap.hpp"
 29 #include "gc/shared/barrierSet.hpp"
 30 #include "gc/shared/barrierSetNMethod.hpp"
 31 #include "gc/shared/oopStorageSet.hpp"
 32 #include "gc/shared/oopStorageParState.inline.hpp"
 33 #include "gc/shared/oopStorageSetParState.inline.hpp"
 34 #include "gc/shared/suspendibleThreadSet.hpp"
 35 #include "gc/z/zBarrierSetNMethod.hpp"
 36 #include "gc/z/zGlobals.hpp"
 37 #include "gc/z/zNMethod.hpp"
 38 #include "gc/z/zOopClosures.inline.hpp"
 39 #include "gc/z/zRootsIterator.hpp"
 40 #include "gc/z/zStat.hpp"
 41 #include "gc/z/zThreadLocalData.hpp"
 42 #include "memory/iterator.hpp"
 43 #include "memory/resourceArea.hpp"
 44 #include "memory/universe.hpp"
 45 #include "prims/jvmtiExport.hpp"
 46 #include "prims/resolvedMethodTable.hpp"
 47 #include "runtime/atomic.hpp"
 48 #include "runtime/safepoint.hpp"
 49 #include "runtime/synchronizer.hpp"
 50 #include "runtime/thread.hpp"
 51 #include "runtime/vmThread.hpp"
 52 #include "services/management.hpp"
 53 #include "utilities/debug.hpp"
 54 #if INCLUDE_JFR
 55 #include "jfr/jfr.hpp"
 56 #endif
 57 
 58 static const ZStatSubPhase ZSubPhasePauseRootsSetup("Pause Roots Setup");
 59 static const ZStatSubPhase ZSubPhasePauseRoots("Pause Roots");
 60 static const ZStatSubPhase ZSubPhasePauseRootsTeardown("Pause Roots Teardown");
 61 static const ZStatSubPhase ZSubPhasePauseRootsUniverse("Pause Roots Universe");
 62 static const ZStatSubPhase ZSubPhasePauseRootsObjectSynchronizer("Pause Roots ObjectSynchronizer");
 63 static const ZStatSubPhase ZSubPhasePauseRootsManagement("Pause Roots Management");
 64 static const ZStatSubPhase ZSubPhasePauseRootsJVMTIExport("Pause Roots JVMTIExport");
 65 static const ZStatSubPhase ZSubPhasePauseRootsJVMTIWeakExport("Pause Roots JVMTIWeakExport");
 66 static const ZStatSubPhase ZSubPhasePauseRootsVMThread("Pause Roots VM Thread");
 67 static const ZStatSubPhase ZSubPhasePauseRootsJavaThreads("Pause Roots Java Threads");
 68 static const ZStatSubPhase ZSubPhasePauseRootsCodeCache("Pause Roots CodeCache");
 69 
 70 static const ZStatSubPhase ZSubPhaseConcurrentRootsSetup("Concurrent Roots Setup");
 71 static const ZStatSubPhase ZSubPhaseConcurrentRoots("Concurrent Roots");
 72 static const ZStatSubPhase ZSubPhaseConcurrentRootsTeardown("Concurrent Roots Teardown");
 73 static const ZStatSubPhase ZSubPhaseConcurrentRootsOopStorageSet("Concurrent Roots OopStorageSet");
 74 static const ZStatSubPhase ZSubPhaseConcurrentRootsClassLoaderDataGraph("Concurrent Roots ClassLoaderDataGraph");
 75 
 76 static const ZStatSubPhase ZSubPhasePauseWeakRootsSetup("Pause Weak Roots Setup");
 77 static const ZStatSubPhase ZSubPhasePauseWeakRoots("Pause Weak Roots");
 78 static const ZStatSubPhase ZSubPhasePauseWeakRootsTeardown("Pause Weak Roots Teardown");
 79 static const ZStatSubPhase ZSubPhasePauseWeakRootsJVMTIWeakExport("Pause Weak Roots JVMTIWeakExport");
 80 static const ZStatSubPhase ZSubPhasePauseWeakRootsJFRWeak("Pause Weak Roots JFRWeak");
 81 
 82 static const ZStatSubPhase ZSubPhaseConcurrentWeakRoots("Concurrent Weak Roots");
 83 static const ZStatSubPhase ZSubPhaseConcurrentWeakRootsVMWeakHandles("Concurrent Weak Roots VMWeakHandles");
 84 static const ZStatSubPhase ZSubPhaseConcurrentWeakRootsJNIWeakHandles("Concurrent Weak Roots JNIWeakHandles");
 85 static const ZStatSubPhase ZSubPhaseConcurrentWeakRootsStringTable("Concurrent Weak Roots StringTable");
 86 static const ZStatSubPhase ZSubPhaseConcurrentWeakRootsResolvedMethodTable("Concurrent Weak Roots ResolvedMethodTable");
 87 
 88 template <typename T, void (T::*F)(ZRootsIteratorClosure*)>
 89 ZSerialOopsDo<T, F>::ZSerialOopsDo(T* iter) :
 90     _iter(iter),
 91     _claimed(false) {}
 92 
 93 template <typename T, void (T::*F)(ZRootsIteratorClosure*)>
 94 void ZSerialOopsDo<T, F>::oops_do(ZRootsIteratorClosure* cl) {
 95   if (!_claimed && Atomic::cmpxchg(&_claimed, false, true) == false) {
 96     (_iter->*F)(cl);
 97   }
 98 }
 99 
100 template <typename T, void (T::*F)(ZRootsIteratorClosure*)>
101 ZParallelOopsDo<T, F>::ZParallelOopsDo(T* iter) :
102     _iter(iter),
103     _completed(false) {}
104 
105 template <typename T, void (T::*F)(ZRootsIteratorClosure*)>
106 void ZParallelOopsDo<T, F>::oops_do(ZRootsIteratorClosure* cl) {
107   if (!_completed) {
108     (_iter->*F)(cl);
109     if (!_completed) {
110       _completed = true;
111     }
112   }
113 }
114 
115 template <typename T, void (T::*F)(BoolObjectClosure*, ZRootsIteratorClosure*)>
116 ZSerialWeakOopsDo<T, F>::ZSerialWeakOopsDo(T* iter) :
117     _iter(iter),
118     _claimed(false) {}
119 
120 template <typename T, void (T::*F)(BoolObjectClosure*, ZRootsIteratorClosure*)>
121 void ZSerialWeakOopsDo<T, F>::weak_oops_do(BoolObjectClosure* is_alive, ZRootsIteratorClosure* cl) {
122   if (!_claimed && Atomic::cmpxchg(&_claimed, false, true) == false) {
123     (_iter->*F)(is_alive, cl);
124   }
125 }
126 
127 template <typename T, void (T::*F)(BoolObjectClosure*, ZRootsIteratorClosure*)>
128 ZParallelWeakOopsDo<T, F>::ZParallelWeakOopsDo(T* iter) :
129     _iter(iter),
130     _completed(false) {}
131 
132 template <typename T, void (T::*F)(BoolObjectClosure*, ZRootsIteratorClosure*)>
133 void ZParallelWeakOopsDo<T, F>::weak_oops_do(BoolObjectClosure* is_alive, ZRootsIteratorClosure* cl) {
134   if (!_completed) {
135     (_iter->*F)(is_alive, cl);
136     if (!_completed) {
137       _completed = true;
138     }
139   }
140 }
141 
142 class ZRootsIteratorCodeBlobClosure : public CodeBlobClosure {
143 private:
144   ZRootsIteratorClosure* const _cl;
145   const bool                   _should_disarm_nmethods;
146 
147 public:
148   ZRootsIteratorCodeBlobClosure(ZRootsIteratorClosure* cl) :
149       _cl(cl),
150       _should_disarm_nmethods(cl->should_disarm_nmethods()) {}
151 
152   virtual void do_code_blob(CodeBlob* cb) {
153     nmethod* const nm = cb->as_nmethod_or_null();
154     if (nm != NULL && nm->oops_do_try_claim()) {
155       ZNMethod::nmethod_oops_do(nm, _cl);
156       assert(!ZNMethod::supports_entry_barrier(nm) ||
157              ZNMethod::is_armed(nm) == _should_disarm_nmethods, "Invalid state");
158       if (_should_disarm_nmethods) {
159         ZNMethod::disarm(nm);
160       }
161     }
162   }
163 };
164 
165 class ZRootsIteratorThreadClosure : public ThreadClosure {
166 private:
167   ZRootsIteratorClosure* const _cl;
168   ResourceMark                 _rm;
169 
170 public:
171   ZRootsIteratorThreadClosure(ZRootsIteratorClosure* cl) :
172       _cl(cl) {}
173 
174   virtual void do_thread(Thread* thread) {
175     ZRootsIteratorCodeBlobClosure code_cl(_cl);
176     thread->oops_do(_cl, ClassUnloading ? &code_cl : NULL);
177     _cl->do_thread(thread);
178   }
179 };
180 
181 ZJavaThreadsIterator::ZJavaThreadsIterator() :
182     _threads(),
183     _claimed(0) {}
184 
185 uint ZJavaThreadsIterator::claim() {
186   return Atomic::fetch_and_add(&_claimed, 1u);
187 }
188 
189 void ZJavaThreadsIterator::threads_do(ThreadClosure* cl) {
190   for (uint i = claim(); i < _threads.length(); i = claim()) {
191     cl->do_thread(_threads.thread_at(i));
192   }
193 }
194 
195 ZRootsIterator::ZRootsIterator(bool visit_jvmti_weak_export) :
196     _visit_jvmti_weak_export(visit_jvmti_weak_export),
197     _java_threads_iter(),
198     _universe(this),
199     _object_synchronizer(this),
200     _management(this),
201     _jvmti_export(this),
202     _jvmti_weak_export(this),
203     _vm_thread(this),
204     _java_threads(this),
205     _code_cache(this) {
206   assert(SafepointSynchronize::is_at_safepoint(), "Should be at safepoint");
207   ZStatTimer timer(ZSubPhasePauseRootsSetup);
208   COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::clear());
209   if (ClassUnloading) {
210     nmethod::oops_do_marking_prologue();
211   } else {
212     ZNMethod::oops_do_begin();
213   }
214 }
215 
216 ZRootsIterator::~ZRootsIterator() {
217   ZStatTimer timer(ZSubPhasePauseRootsTeardown);
218   ResourceMark rm;
219   if (ClassUnloading) {
220     nmethod::oops_do_marking_epilogue();
221   } else {
222     ZNMethod::oops_do_end();
223   }
224 
225   COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::update_pointers());
226 }
227 
228 void ZRootsIterator::do_universe(ZRootsIteratorClosure* cl) {
229   ZStatTimer timer(ZSubPhasePauseRootsUniverse);
230   Universe::oops_do(cl);
231 }
232 
233 void ZRootsIterator::do_object_synchronizer(ZRootsIteratorClosure* cl) {
234   ZStatTimer timer(ZSubPhasePauseRootsObjectSynchronizer);
235   ObjectSynchronizer::oops_do(cl);
236 }
237 
238 void ZRootsIterator::do_management(ZRootsIteratorClosure* cl) {
239   ZStatTimer timer(ZSubPhasePauseRootsManagement);
240   Management::oops_do(cl);
241 }
242 
243 void ZRootsIterator::do_jvmti_export(ZRootsIteratorClosure* cl) {
244   ZStatTimer timer(ZSubPhasePauseRootsJVMTIExport);
245   JvmtiExport::oops_do(cl);
246 }
247 
248 void ZRootsIterator::do_jvmti_weak_export(ZRootsIteratorClosure* cl) {
249   ZStatTimer timer(ZSubPhasePauseRootsJVMTIWeakExport);
250   AlwaysTrueClosure always_alive;
251   JvmtiExport::weak_oops_do(&always_alive, cl);
252 }
253 
254 void ZRootsIterator::do_vm_thread(ZRootsIteratorClosure* cl) {
255   ZStatTimer timer(ZSubPhasePauseRootsVMThread);
256   ZRootsIteratorThreadClosure thread_cl(cl);
257   thread_cl.do_thread(VMThread::vm_thread());
258 }
259 
260 void ZRootsIterator::do_java_threads(ZRootsIteratorClosure* cl) {
261   ZStatTimer timer(ZSubPhasePauseRootsJavaThreads);
262   ZRootsIteratorThreadClosure thread_cl(cl);
263   _java_threads_iter.threads_do(&thread_cl);
264 }
265 
266 void ZRootsIterator::do_code_cache(ZRootsIteratorClosure* cl) {
267   ZStatTimer timer(ZSubPhasePauseRootsCodeCache);
268   ZNMethod::oops_do(cl);
269 }
270 
271 void ZRootsIterator::oops_do(ZRootsIteratorClosure* cl) {
272   ZStatTimer timer(ZSubPhasePauseRoots);
273   _universe.oops_do(cl);
274   _object_synchronizer.oops_do(cl);
275   _management.oops_do(cl);
276   _jvmti_export.oops_do(cl);
277   _vm_thread.oops_do(cl);
278   _java_threads.oops_do(cl);
279   if (!ClassUnloading) {
280     _code_cache.oops_do(cl);
281   }
282   if (_visit_jvmti_weak_export) {
283     _jvmti_weak_export.oops_do(cl);
284   }
285 }
286 
287 ZConcurrentRootsIterator::ZConcurrentRootsIterator(int cld_claim) :
288     _oop_storage_set_iter(),
289     _cld_claim(cld_claim),
290     _oop_storage_set(this),
291     _class_loader_data_graph(this) {
292   ZStatTimer timer(ZSubPhaseConcurrentRootsSetup);
293   ClassLoaderDataGraph::clear_claimed_marks(cld_claim);
294 }
295 
296 ZConcurrentRootsIterator::~ZConcurrentRootsIterator() {
297   ZStatTimer timer(ZSubPhaseConcurrentRootsTeardown);
298 }
299 
300 void ZConcurrentRootsIterator::do_oop_storage_set(ZRootsIteratorClosure* cl) {
301   ZStatTimer timer(ZSubPhaseConcurrentRootsOopStorageSet);
302   _oop_storage_set_iter.oops_do(cl);
303 }
304 
305 void ZConcurrentRootsIterator::do_class_loader_data_graph(ZRootsIteratorClosure* cl) {
306   ZStatTimer timer(ZSubPhaseConcurrentRootsClassLoaderDataGraph);
307   CLDToOopClosure cld_cl(cl, _cld_claim);
308   ClassLoaderDataGraph::always_strong_cld_do(&cld_cl);
309 }
310 
311 void ZConcurrentRootsIterator::oops_do(ZRootsIteratorClosure* cl) {
312   ZStatTimer timer(ZSubPhaseConcurrentRoots);
313   _oop_storage_set.oops_do(cl);
314   _class_loader_data_graph.oops_do(cl);
315 }
316 
317 ZWeakRootsIterator::ZWeakRootsIterator() :
318     _jvmti_weak_export(this),
319     _jfr_weak(this) {
320   assert(SafepointSynchronize::is_at_safepoint(), "Should be at safepoint");
321   ZStatTimer timer(ZSubPhasePauseWeakRootsSetup);
322 }
323 
324 ZWeakRootsIterator::~ZWeakRootsIterator() {
325   ZStatTimer timer(ZSubPhasePauseWeakRootsTeardown);
326 }
327 
328 void ZWeakRootsIterator::do_jvmti_weak_export(BoolObjectClosure* is_alive, ZRootsIteratorClosure* cl) {
329   ZStatTimer timer(ZSubPhasePauseWeakRootsJVMTIWeakExport);
330   JvmtiExport::weak_oops_do(is_alive, cl);
331 }
332 
333 void ZWeakRootsIterator::do_jfr_weak(BoolObjectClosure* is_alive, ZRootsIteratorClosure* cl) {
334 #if INCLUDE_JFR
335   ZStatTimer timer(ZSubPhasePauseWeakRootsJFRWeak);
336   Jfr::weak_oops_do(is_alive, cl);
337 #endif
338 }
339 
340 void ZWeakRootsIterator::weak_oops_do(BoolObjectClosure* is_alive, ZRootsIteratorClosure* cl) {
341   ZStatTimer timer(ZSubPhasePauseWeakRoots);
342   _jvmti_weak_export.weak_oops_do(is_alive, cl);
343   _jfr_weak.weak_oops_do(is_alive, cl);
344 }
345 
346 void ZWeakRootsIterator::oops_do(ZRootsIteratorClosure* cl) {
347   AlwaysTrueClosure always_alive;
348   weak_oops_do(&always_alive, cl);
349 }
350 
351 ZConcurrentWeakRootsIterator::ZConcurrentWeakRootsIterator() :
352     _vm_weak_handles_iter(OopStorageSet::vm_weak()),
353     _jni_weak_handles_iter(OopStorageSet::jni_weak()),
354     _string_table_iter(OopStorageSet::string_table_weak()),
355     _resolved_method_table_iter(OopStorageSet::resolved_method_table_weak()),
356     _vm_weak_handles(this),
357     _jni_weak_handles(this),
358     _string_table(this),
359     _resolved_method_table(this) {
360   StringTable::reset_dead_counter();
361   ResolvedMethodTable::reset_dead_counter();
362 }
363 
364 ZConcurrentWeakRootsIterator::~ZConcurrentWeakRootsIterator() {
365   StringTable::finish_dead_counter();
366   ResolvedMethodTable::finish_dead_counter();
367 }
368 
369 void ZConcurrentWeakRootsIterator::do_vm_weak_handles(ZRootsIteratorClosure* cl) {
370   ZStatTimer timer(ZSubPhaseConcurrentWeakRootsVMWeakHandles);
371   _vm_weak_handles_iter.oops_do(cl);
372 }
373 
374 void ZConcurrentWeakRootsIterator::do_jni_weak_handles(ZRootsIteratorClosure* cl) {
375   ZStatTimer timer(ZSubPhaseConcurrentWeakRootsJNIWeakHandles);
376   _jni_weak_handles_iter.oops_do(cl);
377 }
378 
379 template <class Container>
380 class ZDeadCounterClosure : public ZRootsIteratorClosure  {
381 private:
382   ZRootsIteratorClosure* const _cl;
383   size_t                       _ndead;
384 
385 public:
386   ZDeadCounterClosure(ZRootsIteratorClosure* cl) :
387       _cl(cl),
388       _ndead(0) {}
389 
390   ~ZDeadCounterClosure() {
391     Container::inc_dead_counter(_ndead);
392   }
393 
394   virtual void do_oop(oop* p) {
395     _cl->do_oop(p);
396     if (*p == NULL) {
397       _ndead++;
398     }
399   }
400 
401   virtual void do_oop(narrowOop* p) {
402     ShouldNotReachHere();
403   }
404 };
405 
406 void ZConcurrentWeakRootsIterator::do_string_table(ZRootsIteratorClosure* cl) {
407   ZStatTimer timer(ZSubPhaseConcurrentWeakRootsStringTable);
408   ZDeadCounterClosure<StringTable> counter_cl(cl);
409   _string_table_iter.oops_do(&counter_cl);
410 }
411 
412 void ZConcurrentWeakRootsIterator::do_resolved_method_table(ZRootsIteratorClosure* cl) {
413   ZStatTimer timer(ZSubPhaseConcurrentWeakRootsResolvedMethodTable);
414   ZDeadCounterClosure<ResolvedMethodTable> counter_cl(cl);
415   _resolved_method_table_iter.oops_do(&counter_cl);
416 }
417 
418 void ZConcurrentWeakRootsIterator::oops_do(ZRootsIteratorClosure* cl) {
419   ZStatTimer timer(ZSubPhaseConcurrentWeakRoots);
420   _vm_weak_handles.oops_do(cl);
421   _jni_weak_handles.oops_do(cl);
422   _string_table.oops_do(cl);
423   _resolved_method_table.oops_do(cl);
424 }