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() :
61 _heap(ShenandoahHeap::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;
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 void ShenandoahNMethod::heal_nmethod(nmethod* nm) {
179 assert(ShenandoahHeap::heap()->is_concurrent_root_in_progress(), "Only this phase");
180 ShenandoahNMethod* data = gc_data(nm);
181 assert(data != NULL, "Sanity");
182 assert(data->lock()->owned_by_self(), "Must hold the lock");
183
184 ShenandoahEvacOOMScope evac_scope;
185 ShenandoahEvacuateUpdateRootsClosure<> cl;
186 data->oops_do(&cl, true /*fix relocation*/);
187 }
188
189 #ifdef ASSERT
190 void ShenandoahNMethod::assert_alive_and_correct() {
191 assert(_nm->is_alive(), "only alive nmethods here");
192 ShenandoahHeap* heap = ShenandoahHeap::heap();
193 for (int c = 0; c < _oops_count; c++) {
194 oop *loc = _oops[c];
195 assert(_nm->code_contains((address) loc) || _nm->oops_contains(loc), "nmethod should contain the oop*");
196 oop o = RawAccess<>::oop_load(loc);
197 shenandoah_assert_correct_except(loc, o, o == NULL || heap->is_full_gc_move_in_progress());
198 }
199
200 oop* const begin = _nm->oops_begin();
201 oop* const end = _nm->oops_end();
202 for (oop* p = begin; p < end; p++) {
203 if (*p != Universe::non_oop_word()) {
204 oop o = RawAccess<>::oop_load(p);
205 shenandoah_assert_correct_except(p, o, o == NULL || heap->is_full_gc_move_in_progress());
206 }
207 }
208 }
209
210 class ShenandoahNMethodOopDetector : public OopClosure {
211 private:
212 ResourceMark rm; // For growable array allocation below.
213 GrowableArray<oop*> _oops;
214
215 public:
216 ShenandoahNMethodOopDetector() : _oops(10) {};
217
218 void do_oop(oop* o) {
219 _oops.append(o);
220 }
221 void do_oop(narrowOop* o) {
222 fatal("NMethods should not have compressed oops embedded.");
223 }
224
225 GrowableArray<oop*>* oops() {
226 return &_oops;
227 }
228
229 bool has_oops() {
230 return !_oops.is_empty();
231 }
232 };
233
234 void ShenandoahNMethod::assert_same_oops(bool allow_dead) {
235 ShenandoahNMethodOopDetector detector;
236 nm()->oops_do(&detector, allow_dead);
237
238 GrowableArray<oop*>* oops = detector.oops();
239
240 int count = _oops_count;
241 for (int index = 0; index < _oops_count; index ++) {
242 assert(oops->contains(_oops[index]), "Must contain this oop");
243 }
244
245 for (oop* p = nm()->oops_begin(); p < nm()->oops_end(); p ++) {
246 if (*p == Universe::non_oop_word()) continue;
247 count++;
248 assert(oops->contains(p), "Must contain this oop");
249 }
250
251 if (oops->length() < count) {
252 stringStream debug_stream;
253 debug_stream.print_cr("detected locs: %d", oops->length());
254 for (int i = 0; i < oops->length(); i++) {
255 debug_stream.print_cr("-> " PTR_FORMAT, p2i(oops->at(i)));
256 }
257 debug_stream.print_cr("recorded oops: %d", _oops_count);
258 for (int i = 0; i < _oops_count; i++) {
259 debug_stream.print_cr("-> " PTR_FORMAT, p2i(_oops[i]));
260 }
261 GrowableArray<oop*> check;
262 bool non_immed;
263 detect_reloc_oops(nm(), check, non_immed);
264 debug_stream.print_cr("check oops: %d", check.length());
265 for (int i = 0; i < check.length(); i++) {
266 debug_stream.print_cr("-> " PTR_FORMAT, p2i(check.at(i)));
267 }
268 fatal("Must match #detected: %d, #recorded: %d, #total: %d, begin: " PTR_FORMAT ", end: " PTR_FORMAT "\n%s",
269 oops->length(), _oops_count, count, p2i(nm()->oops_begin()), p2i(nm()->oops_end()), debug_stream.as_string());
270 }
271 }
272
273 void ShenandoahNMethod::assert_no_oops(nmethod* nm, bool allow_dead) {
274 ShenandoahNMethodOopDetector detector;
275 nm->oops_do(&detector, allow_dead);
276 assert(detector.oops()->length() == 0, "Should not have oops");
277 }
278 #endif
279
280 ShenandoahNMethodTable::ShenandoahNMethodTable() :
281 _heap(ShenandoahHeap::heap()),
282 _size(minSize),
283 _index(0),
284 _iteration_in_progress(false) {
285 _array = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, _size, mtGC);
286 }
287
288 ShenandoahNMethodTable::~ShenandoahNMethodTable() {
289 assert(_array != NULL, "Sanity");
290 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, _array);
291 }
292
293 void ShenandoahNMethodTable::register_nmethod(nmethod* nm) {
294 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
295 assert(_index >= 0 && _index <= _size, "Sanity");
296
297 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
298 ShenandoahReentrantLocker data_locker(data != NULL ? data->lock() : NULL);
299
300 if (data != NULL) {
301 assert(contain(nm), "Must have been registered");
302 assert(nm == data->nm(), "Must be same nmethod");
303 data->update();
304 } else {
305 data = ShenandoahNMethod::for_nmethod(nm);
306 if (data == NULL) {
307 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
308 "Only possible when concurrent class unloading is off");
309 return;
310 }
311 ShenandoahNMethod::attach_gc_data(nm, data);
312 ShenandoahLocker locker(&_lock);
313 log_register_nmethod(nm);
314 append(data);
315 }
316 // Disarm new nmethod
317 ShenandoahNMethod::disarm_nmethod(nm);
318 }
319
320 void ShenandoahNMethodTable::unregister_nmethod(nmethod* nm) {
321 assert_locked_or_safepoint(CodeCache_lock);
322
323 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
324 if (data == NULL) {
325 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
326 "Only possible when concurrent class unloading is off");
327 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/);
328 return;
329 }
330
331 if (Thread::current()->is_Code_cache_sweeper_thread()) {
332 wait_until_concurrent_iteration_done();
333 }
334 log_unregister_nmethod(nm);
335 ShenandoahLocker locker(&_lock);
336 assert(contain(nm), "Must have been registered");
337
338 ShenandoahReentrantLocker data_locker(data->lock());
339 data->mark_unregistered();
340 }
341
342 void ShenandoahNMethodTable::flush_nmethod(nmethod* nm) {
343 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
344 assert(Thread::current()->is_Code_cache_sweeper_thread(), "Must from Sweep thread");
345 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
346 assert(data != NULL || !ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
347 "Only possible when concurrent class unloading is off");
348 if (data == NULL) {
349 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/);
350 return;
351 }
352
353 // Can not alter the array when iteration is in progress
354 wait_until_concurrent_iteration_done();
355 log_flush_nmethod(nm);
356
357 ShenandoahLocker locker(&_lock);
358 int idx = index_of(nm);
359 assert(idx >= 0 && idx < _index, "Invalid index");
360 ShenandoahNMethod::attach_gc_data(nm, NULL);
361 remove(idx);
362 }
363
364 bool ShenandoahNMethodTable::contain(nmethod* nm) const {
365 return index_of(nm) != -1;
366 }
367
368 ShenandoahNMethod* ShenandoahNMethodTable::at(int index) const {
369 assert(index >= 0 && index < _index, "Out of bound");
370 return _array[index];
371 }
372
373 int ShenandoahNMethodTable::index_of(nmethod* nm) const {
374 for (int index = 0; index < length(); index ++) {
375 if (_array[index]->nm() == nm) {
376 return index;
377 }
378 }
379 return -1;
380 }
381
382 void ShenandoahNMethodTable::remove(int idx) {
383 shenandoah_assert_locked_or_safepoint(CodeCache_lock);
384 assert(!_iteration_in_progress, "Can not happen");
385 assert(_index >= 0 && _index <= _size, "Sanity");
386
387 assert(idx >= 0 && idx < _index, "Out of bound");
388 ShenandoahNMethod* snm = _array[idx];
389
390 _index --;
391 _array[idx] = _array[_index];
392
393 delete snm;
394 }
395
396 void ShenandoahNMethodTable::wait_until_concurrent_iteration_done() {
397 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
398 while (iteration_in_progress()) {
399 CodeCache_lock->wait_without_safepoint_check();
400 }
401 }
402
403 void ShenandoahNMethodTable::append(ShenandoahNMethod* snm) {
404 if (is_full()) {
405 int new_size = 2 * _size;
406 ShenandoahNMethod** old_table = _array;
407
408 // Rebuild table and replace current one
409 rebuild(new_size);
410
411 // An iteration is in progress over early snapshot,
412 // can not release the array until iteration is completed
413 if (!iteration_in_progress()) {
414 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, old_table);
415 }
416 }
417
418 _array[_index ++] = snm;
419 assert(_index >= 0 && _index <= _size, "Sanity");
420 }
421
422 void ShenandoahNMethodTable::rebuild(int size) {
423 ShenandoahNMethod** arr = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, size, mtGC);
424 for (int index = 0; index < _index; index ++) {
425 arr[index] = _array[index];
426 }
427 _array = arr;
428 _size = size;
429 }
430
431 ShenandoahNMethodTableSnapshot* ShenandoahNMethodTable::snapshot_for_iteration() {
432 assert(!iteration_in_progress(), "Already in progress");
433 _iteration_in_progress = true;
434
435 return new ShenandoahNMethodTableSnapshot(this);
436 }
437
438 void ShenandoahNMethodTable::finish_iteration(ShenandoahNMethodTableSnapshot* snapshot) {
439 assert(iteration_in_progress(), "Why we here?");
440 assert(snapshot != NULL, "No snapshot");
441 _iteration_in_progress = false;
442
443 // Table has been rebuilt during iteration, free old table
444 if (snapshot->_array != _array) {
445 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, snapshot->_array);
446 }
447 delete snapshot;
448 }
449
450 void ShenandoahNMethodTable::log_register_nmethod(nmethod* nm) {
451 LogTarget(Debug, gc, nmethod) log;
452 if (!log.is_enabled()) {
453 return;
454 }
455
456 ResourceMark rm;
457 log.print("Register NMethod: %s.%s [" PTR_FORMAT "] (%s)",
458 nm->method()->method_holder()->external_name(),
459 nm->method()->name()->as_C_string(),
460 p2i(nm),
461 nm->compiler_name());
462 }
463
464 void ShenandoahNMethodTable::log_unregister_nmethod(nmethod* nm) {
465 LogTarget(Debug, gc, nmethod) log;
466 if (!log.is_enabled()) {
467 return;
468 }
469
470 ResourceMark rm;
471 log.print("Unregister NMethod: %s.%s [" PTR_FORMAT "]",
472 nm->method()->method_holder()->external_name(),
473 nm->method()->name()->as_C_string(),
474 p2i(nm));
475 }
476
477 void ShenandoahNMethodTable::log_flush_nmethod(nmethod* nm) {
478 LogTarget(Debug, gc, nmethod) log;
479 if (!log.is_enabled()) {
480 return;
481 }
482
483 ResourceMark rm;
484 log.print("Flush NMethod: (" PTR_FORMAT ")", p2i(nm));
485 }
486
487 #ifdef ASSERT
488 void ShenandoahNMethodTable::assert_nmethods_alive_and_correct() {
489 assert_locked_or_safepoint(CodeCache_lock);
490
491 for (int index = 0; index < length(); index ++) {
492 ShenandoahNMethod* m = _array[index];
493 // Concurrent unloading may have dead nmethods to be cleaned by sweeper
494 if (m->is_unregistered()) continue;
495 m->assert_alive_and_correct();
496 }
497 }
498 #endif
499
500 ShenandoahNMethodTableSnapshot::ShenandoahNMethodTableSnapshot(ShenandoahNMethodTable* table) :
501 _heap(ShenandoahHeap::heap()), _table(table), _array(table->_array), _length(table->_index), _claimed(0) {
502 }
503
504 void ShenandoahNMethodTableSnapshot::concurrent_nmethods_do(NMethodClosure* cl) {
505 size_t stride = 256; // educated guess
506
507 ShenandoahNMethod** list = _array;
508 size_t max = (size_t)_length;
509 while (_claimed < max) {
510 size_t cur = Atomic::fetch_and_add(&_claimed, stride);
511 size_t start = cur;
512 size_t end = MIN2(cur + stride, max);
513 if (start >= max) break;
514
515 for (size_t idx = start; idx < end; idx++) {
516 ShenandoahNMethod* data = list[idx];
517 assert(data != NULL, "Should not be NULL");
518 if (!data->is_unregistered()) {
519 cl->do_nmethod(data->nm());
520 }
521 }
522 }
523 }
524
525 ShenandoahConcurrentNMethodIterator::ShenandoahConcurrentNMethodIterator(ShenandoahNMethodTable* table) :
526 _table(table), _table_snapshot(NULL) {
527 }
528
529 void ShenandoahConcurrentNMethodIterator::nmethods_do_begin() {
530 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
531 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
532 "Only for concurrent class unloading");
533 _table_snapshot = _table->snapshot_for_iteration();
534 }
535
536 void ShenandoahConcurrentNMethodIterator::nmethods_do(NMethodClosure* cl) {
537 assert(_table_snapshot != NULL, "Must first call nmethod_do_begin()");
538 _table_snapshot->concurrent_nmethods_do(cl);
539 }
540
541 void ShenandoahConcurrentNMethodIterator::nmethods_do_end() {
542 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
543 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
544 "Only for concurrent class unloading");
545 _table->finish_iteration(_table_snapshot);
546 CodeCache_lock->notify_all();
547 }