1 /*
2 * Copyright (c) 2019, 2020, Red Hat, Inc. 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
27 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
28 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahNMethod.inline.hpp"
31 #include "memory/resourceArea.hpp"
32
33 ShenandoahNMethod::ShenandoahNMethod(nmethod* nm, GrowableArray<oop*>& oops, bool non_immediate_oops) :
34 _nm(nm), _oops(NULL), _oops_count(0), _unregistered(false) {
35
36 if (!oops.is_empty()) {
37 _oops_count = oops.length();
38 _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC);
39 for (int c = 0; c < _oops_count; c++) {
40 _oops[c] = oops.at(c);
41 }
42 }
43 _has_non_immed_oops = non_immediate_oops;
44
45 assert_same_oops();
46 }
47
48 ShenandoahNMethod::~ShenandoahNMethod() {
49 if (_oops != NULL) {
50 FREE_C_HEAP_ARRAY(oop*, _oops);
51 }
52 }
53
54 class ShenandoahHasCSetOopClosure : public OopClosure {
55 private:
56 ShenandoahHeap* const _heap;
57 bool _has_cset_oops;
58
59 public:
60 ShenandoahHasCSetOopClosure(ShenandoahHeap *heap) :
61 _heap(heap),
62 _has_cset_oops(false) {
63 }
64
65 bool has_cset_oops() const {
66 return _has_cset_oops;
67 }
68
69 void do_oop(oop* p) {
70 oop value = RawAccess<>::oop_load(p);
71 if (!_has_cset_oops && _heap->in_collection_set(value)) {
72 _has_cset_oops = true;
73 }
74 }
75
76 void do_oop(narrowOop* p) {
77 ShouldNotReachHere();
78 }
79 };
80
81 bool ShenandoahNMethod::has_cset_oops(ShenandoahHeap *heap) {
82 ShenandoahHasCSetOopClosure cl(heap);
83 oops_do(&cl);
84 return cl.has_cset_oops();
85 }
86
87 void ShenandoahNMethod::update() {
88 ResourceMark rm;
89 bool non_immediate_oops = false;
90 GrowableArray<oop*> oops;
91
92 detect_reloc_oops(nm(), oops, non_immediate_oops);
93 if (oops.length() != _oops_count) {
94 if (_oops != NULL) {
95 FREE_C_HEAP_ARRAY(oop*, _oops);
96 _oops = NULL;
97 }
98
99 _oops_count = oops.length();
100 if (_oops_count > 0) {
101 _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC);
102 }
103 }
104
105 for (int index = 0; index < _oops_count; index ++) {
106 _oops[index] = oops.at(index);
107 }
108 _has_non_immed_oops = non_immediate_oops;
109
110 assert_same_oops();
111 }
112
113 void ShenandoahNMethod::oops_do(OopClosure* oops, bool fix_relocations) {
114 for (int c = 0; c < _oops_count; c ++) {
115 oops->do_oop(_oops[c]);
116 }
117
118 oop* const begin = _nm->oops_begin();
119 oop* const end = _nm->oops_end();
120 for (oop* p = begin; p < end; p++) {
121 if (*p != Universe::non_oop_word()) {
122 oops->do_oop(p);
123 }
124 }
125
126 if (fix_relocations && _has_non_immed_oops) {
127 _nm->fix_oop_relocations();
128 }
129 }
130
131 void ShenandoahNMethod::detect_reloc_oops(nmethod* nm, GrowableArray<oop*>& oops, bool& has_non_immed_oops) {
132 has_non_immed_oops = false;
133 // Find all oops relocations
134 RelocIterator iter(nm);
135 while (iter.next()) {
136 if (iter.type() != relocInfo::oop_type) {
137 // Not an oop
138 continue;
139 }
140
141 oop_Relocation* r = iter.oop_reloc();
142 if (!r->oop_is_immediate()) {
143 // Non-immediate oop found
144 has_non_immed_oops = true;
145 continue;
146 }
147
148 oop value = r->oop_value();
149 if (value != NULL) {
150 oop* addr = r->oop_addr();
151 shenandoah_assert_correct(addr, value);
152 shenandoah_assert_not_in_cset_except(addr, value, ShenandoahHeap::heap()->cancelled_gc());
153 shenandoah_assert_not_forwarded(addr, value);
154 // Non-NULL immediate oop found. NULL oops can safely be
155 // ignored since the method will be re-registered if they
156 // are later patched to be non-NULL.
157 oops.push(addr);
158 }
159 }
160 }
161
162 ShenandoahNMethod* ShenandoahNMethod::for_nmethod(nmethod* nm) {
163 ResourceMark rm;
164 bool non_immediate_oops = false;
165 GrowableArray<oop*> oops;
166
167 detect_reloc_oops(nm, oops, non_immediate_oops);
168
169 // No embedded oops
170 if(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading() &&
171 oops.is_empty() && nm->oops_begin() >= nm->oops_end()) {
172 return NULL;
173 }
174
175 return new ShenandoahNMethod(nm, oops, non_immediate_oops);
176 }
177
178 template <bool HAS_FWD>
179 class ShenandoahKeepNMethodMetadataAliveClosure : public OopClosure {
180 private:
181 ShenandoahBarrierSet* const _bs;
182 public:
183 ShenandoahKeepNMethodMetadataAliveClosure() :
184 _bs(static_cast<ShenandoahBarrierSet*>(BarrierSet::barrier_set())) {
185 }
186
187 virtual void do_oop(oop* p) {
188 oop obj = RawAccess<>::oop_load(p);
189 if (!CompressedOops::is_null(obj)) {
190 if (HAS_FWD) {
191 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
192 }
193 _bs->enqueue(obj);
194 }
195 }
196
197 virtual void do_oop(narrowOop* p) {
198 ShouldNotReachHere();
199 }
200 };
201
202 void ShenandoahNMethod::heal_nmethod(nmethod* nm) {
203 ShenandoahNMethod* data = gc_data(nm);
204 assert(data != NULL, "Sanity");
205 assert(data->lock()->owned_by_self(), "Must hold the lock");
206
207 ShenandoahHeap* const heap = ShenandoahHeap::heap();
208 if (heap->is_concurrent_mark_in_progress()) {
209 if (heap->has_forwarded_objects()) {
210 ShenandoahKeepNMethodMetadataAliveClosure<true> cl;
211 data->oops_do(&cl);
212 } else {
213 ShenandoahKeepNMethodMetadataAliveClosure<false> cl;
214 data->oops_do(&cl);
215 }
216 } else if (heap->is_concurrent_weak_root_in_progress()) {
217 ShenandoahEvacOOMScope evac_scope;
218 ShenandoahEvacuateUpdateRootsClosure<> cl;
219 data->oops_do(&cl, true /*fix relocation*/);
220 } else {
221 // There is possibility that GC is cancelled when it arrives final mark.
222 // In this case, concurrent root phase is skipped and degenerated GC should be
223 // followed, where nmethods are disarmed.
224 assert(heap->cancelled_gc(), "What else?");
225 }
226 }
227
228 #ifdef ASSERT
229 void ShenandoahNMethod::assert_alive_and_correct() {
230 assert(_nm->is_alive(), "only alive nmethods here");
231 ShenandoahHeap* heap = ShenandoahHeap::heap();
232 for (int c = 0; c < _oops_count; c++) {
233 oop *loc = _oops[c];
234 assert(_nm->code_contains((address) loc) || _nm->oops_contains(loc), "nmethod should contain the oop*");
235 oop o = RawAccess<>::oop_load(loc);
236 shenandoah_assert_correct_except(loc, o, o == NULL || heap->is_full_gc_move_in_progress());
237 }
238
239 oop* const begin = _nm->oops_begin();
240 oop* const end = _nm->oops_end();
241 for (oop* p = begin; p < end; p++) {
242 if (*p != Universe::non_oop_word()) {
243 oop o = RawAccess<>::oop_load(p);
244 shenandoah_assert_correct_except(p, o, o == NULL || heap->is_full_gc_move_in_progress());
245 }
246 }
247 }
248
249 class ShenandoahNMethodOopDetector : public OopClosure {
250 private:
251 ResourceMark rm; // For growable array allocation below.
252 GrowableArray<oop*> _oops;
253
254 public:
255 ShenandoahNMethodOopDetector() : _oops(10) {};
256
257 void do_oop(oop* o) {
258 _oops.append(o);
259 }
260 void do_oop(narrowOop* o) {
261 fatal("NMethods should not have compressed oops embedded.");
262 }
263
264 GrowableArray<oop*>* oops() {
265 return &_oops;
266 }
267
268 bool has_oops() {
269 return !_oops.is_empty();
270 }
271 };
272
273 void ShenandoahNMethod::assert_same_oops(bool allow_dead) {
274 ShenandoahNMethodOopDetector detector;
275 nm()->oops_do(&detector, allow_dead);
276
277 GrowableArray<oop*>* oops = detector.oops();
278
279 int count = _oops_count;
280 for (int index = 0; index < _oops_count; index ++) {
281 assert(oops->contains(_oops[index]), "Must contain this oop");
282 }
283
284 for (oop* p = nm()->oops_begin(); p < nm()->oops_end(); p ++) {
285 if (*p == Universe::non_oop_word()) continue;
286 count++;
287 assert(oops->contains(p), "Must contain this oop");
288 }
289
290 if (oops->length() < count) {
291 stringStream debug_stream;
292 debug_stream.print_cr("detected locs: %d", oops->length());
293 for (int i = 0; i < oops->length(); i++) {
294 debug_stream.print_cr("-> " PTR_FORMAT, p2i(oops->at(i)));
295 }
296 debug_stream.print_cr("recorded oops: %d", _oops_count);
297 for (int i = 0; i < _oops_count; i++) {
298 debug_stream.print_cr("-> " PTR_FORMAT, p2i(_oops[i]));
299 }
300 GrowableArray<oop*> check;
301 bool non_immed;
302 detect_reloc_oops(nm(), check, non_immed);
303 debug_stream.print_cr("check oops: %d", check.length());
304 for (int i = 0; i < check.length(); i++) {
305 debug_stream.print_cr("-> " PTR_FORMAT, p2i(check.at(i)));
306 }
307 fatal("Must match #detected: %d, #recorded: %d, #total: %d, begin: " PTR_FORMAT ", end: " PTR_FORMAT "\n%s",
308 oops->length(), _oops_count, count, p2i(nm()->oops_begin()), p2i(nm()->oops_end()), debug_stream.as_string());
309 }
310 }
311
312 void ShenandoahNMethod::assert_no_oops(nmethod* nm, bool allow_dead) {
313 ShenandoahNMethodOopDetector detector;
314 nm->oops_do(&detector, allow_dead);
315 assert(detector.oops()->length() == 0, "Should not have oops");
316 }
317 #endif
318
319 ShenandoahNMethodTable::ShenandoahNMethodTable() :
320 _heap(ShenandoahHeap::heap()),
321 _index(0),
322 _itr_cnt(0) {
323 _list = new ShenandoahNMethodList(minSize);
324 }
325
326 ShenandoahNMethodTable::~ShenandoahNMethodTable() {
327 assert(_list != NULL, "Sanity");
328 _list->release();
329 }
330
331 void ShenandoahNMethodTable::register_nmethod(nmethod* nm) {
332 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
333 assert(_index >= 0 && _index <= _list->size(), "Sanity");
334
335 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
336 ShenandoahReentrantLocker data_locker(data != NULL ? data->lock() : NULL);
337
338 if (data != NULL) {
339 assert(contain(nm), "Must have been registered");
340 assert(nm == data->nm(), "Must be same nmethod");
341 data->update();
342 } else {
343 data = ShenandoahNMethod::for_nmethod(nm);
344 if (data == NULL) {
345 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
346 "Only possible when concurrent class unloading is off");
347 return;
348 }
349 ShenandoahNMethod::attach_gc_data(nm, data);
350 ShenandoahLocker locker(&_lock);
351 log_register_nmethod(nm);
352 append(data);
353 }
354 // Disarm new nmethod
355 ShenandoahNMethod::disarm_nmethod(nm);
356 }
357
358 void ShenandoahNMethodTable::unregister_nmethod(nmethod* nm) {
359 assert_locked_or_safepoint(CodeCache_lock);
360
361 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
362 if (data == NULL) {
363 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
364 "Only possible when concurrent class unloading is off");
365 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/);
366 return;
367 }
368
369 if (Thread::current()->is_Code_cache_sweeper_thread()) {
370 wait_until_concurrent_iteration_done();
371 }
372 log_unregister_nmethod(nm);
373 ShenandoahLocker locker(&_lock);
374 assert(contain(nm), "Must have been registered");
375
376 ShenandoahReentrantLocker data_locker(data->lock());
377 data->mark_unregistered();
378 }
379
380 void ShenandoahNMethodTable::flush_nmethod(nmethod* nm) {
381 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
382 assert(Thread::current()->is_Code_cache_sweeper_thread(), "Must from Sweep thread");
383 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
384 assert(data != NULL || !ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
385 "Only possible when concurrent class unloading is off");
386 if (data == NULL) {
387 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/);
388 return;
389 }
390
391 // Can not alter the array when iteration is in progress
392 wait_until_concurrent_iteration_done();
393 log_flush_nmethod(nm);
394
395 ShenandoahLocker locker(&_lock);
396 int idx = index_of(nm);
397 assert(idx >= 0 && idx < _index, "Invalid index");
398 ShenandoahNMethod::attach_gc_data(nm, NULL);
399 remove(idx);
400 }
401
402 bool ShenandoahNMethodTable::contain(nmethod* nm) const {
403 return index_of(nm) != -1;
404 }
405
406 ShenandoahNMethod* ShenandoahNMethodTable::at(int index) const {
407 assert(index >= 0 && index < _index, "Out of bound");
408 return _list->at(index);
409 }
410
411 int ShenandoahNMethodTable::index_of(nmethod* nm) const {
412 for (int index = 0; index < length(); index ++) {
413 if (at(index)->nm() == nm) {
414 return index;
415 }
416 }
417 return -1;
418 }
419
420 void ShenandoahNMethodTable::remove(int idx) {
421 shenandoah_assert_locked_or_safepoint(CodeCache_lock);
422 assert(!iteration_in_progress(), "Can not happen");
423 assert(_index >= 0 && _index <= _list->size(), "Sanity");
424
425 assert(idx >= 0 && idx < _index, "Out of bound");
426 ShenandoahNMethod* snm = _list->at(idx);
427 ShenandoahNMethod* tmp = _list->at(_index - 1);
428 _list->set(idx, tmp);
429 _index --;
430
431 delete snm;
432 }
433
434 void ShenandoahNMethodTable::wait_until_concurrent_iteration_done() {
435 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
436 while (iteration_in_progress()) {
437 CodeCache_lock->wait_without_safepoint_check();
438 }
439 }
440
441 void ShenandoahNMethodTable::append(ShenandoahNMethod* snm) {
442 if (is_full()) {
443 int new_size = 2 * _list->size();
444 // Rebuild table and replace current one
445 rebuild(new_size);
446 }
447
448 _list->set(_index++, snm);
449 assert(_index >= 0 && _index <= _list->size(), "Sanity");
450 }
451
452 void ShenandoahNMethodTable::rebuild(int size) {
453 ShenandoahNMethodList* new_list = new ShenandoahNMethodList(size);
454 new_list->transfer(_list, _index);
455
456 // Release old list
457 _list->release();
458 _list = new_list;
459 }
460
461 ShenandoahNMethodTableSnapshot* ShenandoahNMethodTable::snapshot_for_iteration() {
462 _itr_cnt++;
463 return new ShenandoahNMethodTableSnapshot(this);
464 }
465
466 void ShenandoahNMethodTable::finish_iteration(ShenandoahNMethodTableSnapshot* snapshot) {
467 assert(iteration_in_progress(), "Why we here?");
468 assert(snapshot != NULL, "No snapshot");
469 _itr_cnt--;
470
471 delete snapshot;
472 }
473
474 void ShenandoahNMethodTable::log_register_nmethod(nmethod* nm) {
475 LogTarget(Debug, gc, nmethod) log;
476 if (!log.is_enabled()) {
477 return;
478 }
479
480 ResourceMark rm;
481 log.print("Register NMethod: %s.%s [" PTR_FORMAT "] (%s)",
482 nm->method()->method_holder()->external_name(),
483 nm->method()->name()->as_C_string(),
484 p2i(nm),
485 nm->compiler_name());
486 }
487
488 void ShenandoahNMethodTable::log_unregister_nmethod(nmethod* nm) {
489 LogTarget(Debug, gc, nmethod) log;
490 if (!log.is_enabled()) {
491 return;
492 }
493
494 ResourceMark rm;
495 log.print("Unregister NMethod: %s.%s [" PTR_FORMAT "]",
496 nm->method()->method_holder()->external_name(),
497 nm->method()->name()->as_C_string(),
498 p2i(nm));
499 }
500
501 void ShenandoahNMethodTable::log_flush_nmethod(nmethod* nm) {
502 LogTarget(Debug, gc, nmethod) log;
503 if (!log.is_enabled()) {
504 return;
505 }
506
507 ResourceMark rm;
508 log.print("Flush NMethod: (" PTR_FORMAT ")", p2i(nm));
509 }
510
511 #ifdef ASSERT
512 void ShenandoahNMethodTable::assert_nmethods_alive_and_correct() {
513 assert_locked_or_safepoint(CodeCache_lock);
514
515 for (int index = 0; index < length(); index ++) {
516 ShenandoahNMethod* m = _list->at(index);
517 // Concurrent unloading may have dead nmethods to be cleaned by sweeper
518 if (m->is_unregistered()) continue;
519 m->assert_alive_and_correct();
520 }
521 }
522 #endif
523
524
525 ShenandoahNMethodList::ShenandoahNMethodList(int size) :
526 _size(size), _ref_count(1) {
527 _list = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, size, mtGC);
528 }
529
530 ShenandoahNMethodList::~ShenandoahNMethodList() {
531 assert(_list != NULL, "Sanity");
532 assert(_ref_count == 0, "Must be");
533 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, _list);
534 }
535
536 void ShenandoahNMethodList::transfer(ShenandoahNMethodList* const list, int limit) {
537 assert(limit <= size(), "Sanity");
538 ShenandoahNMethod** old_list = list->list();
539 for (int index = 0; index < limit; index++) {
540 _list[index] = old_list[index];
541 }
542 }
543
544 ShenandoahNMethodList* ShenandoahNMethodList::acquire() {
545 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
546 _ref_count++;
547 return this;
548 }
549
550 void ShenandoahNMethodList::release() {
551 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
552 _ref_count--;
553 if (_ref_count == 0) {
554 delete this;
555 }
556 }
557
558 ShenandoahNMethodTableSnapshot::ShenandoahNMethodTableSnapshot(ShenandoahNMethodTable* table) :
559 _heap(ShenandoahHeap::heap()), _list(table->_list->acquire()), _limit(table->_index), _claimed(0) {
560 }
561
562 ShenandoahNMethodTableSnapshot::~ShenandoahNMethodTableSnapshot() {
563 _list->release();
564 }
565
566 void ShenandoahNMethodTableSnapshot::concurrent_nmethods_do(NMethodClosure* cl) {
567 size_t stride = 256; // educated guess
568
569 ShenandoahNMethod** list = _list->list();
570 size_t max = (size_t)_limit;
571 while (_claimed < max) {
572 size_t cur = Atomic::fetch_and_add(&_claimed, stride);
573 size_t start = cur;
574 size_t end = MIN2(cur + stride, max);
575 if (start >= max) break;
576
577 for (size_t idx = start; idx < end; idx++) {
578 ShenandoahNMethod* data = list[idx];
579 assert(data != NULL, "Should not be NULL");
580 if (!data->is_unregistered()) {
581 cl->do_nmethod(data->nm());
582 }
583 }
584 }
585 }
586
587 ShenandoahConcurrentNMethodIterator::ShenandoahConcurrentNMethodIterator(ShenandoahNMethodTable* table) :
588 _table(table), _table_snapshot(NULL) {
589 }
590
591 void ShenandoahConcurrentNMethodIterator::nmethods_do_begin() {
592 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
593 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
594 "Only for concurrent class unloading");
595 _table_snapshot = _table->snapshot_for_iteration();
596 }
597
598 void ShenandoahConcurrentNMethodIterator::nmethods_do(NMethodClosure* cl) {
599 assert(_table_snapshot != NULL, "Must first call nmethod_do_begin()");
600 _table_snapshot->concurrent_nmethods_do(cl);
601 }
602
603 void ShenandoahConcurrentNMethodIterator::nmethods_do_end() {
604 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
605 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
606 "Only for concurrent class unloading");
607 _table->finish_iteration(_table_snapshot);
608 CodeCache_lock->notify_all();
609 }