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 = 0;
241 for (int index = 0; index < _oops_count; index ++) {
242 count++;
243 assert(oops->contains(_oops[index]), "Must contain this oop");
244 }
245
246 for (oop* p = nm()->oops_begin(); p < nm()->oops_end(); p ++) {
247 if (*p == Universe::non_oop_word()) continue;
248 count++;
249 assert(oops->contains(p), "Must contain this oop");
250 }
251 #ifdef ASSERT_DISABLED
252 if (oops->length() < count) {
253 tty->print_cr("detected locs: %d", oops->length());
254 for (int i = 0; i < oops->length(); i++) {
255 tty->print_cr("-> " PTR_FORMAT, p2i(oops->at(i)));
256 }
257 tty->print_cr("recorded oops: %d", _oops_count);
258 for (int i = 0; i < _oops_count; i++) {
259 tty->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 tty->print_cr("check oops: %d", check.length());
265 for (int i = 0; i < check.length(); i++) {
266 tty->print_cr("-> " PTR_FORMAT, p2i(check.at(i)));
267 }
268 assert(false, "Must match #detected: %d, #recorded: %d, #total: %d, begin: " PTR_FORMAT ", end: " PTR_FORMAT, oops->length(), _oops_count, count, p2i(nm()->oops_begin()), p2i(nm()->oops_end()));
269 }
270 #endif
271 assert(oops->length() >= count,
272 "Must match #detected: %d, #recorded: %d, #total: %d, begin: " PTR_FORMAT ", end: " PTR_FORMAT,
273 oops->length(), _oops_count, count, p2i(nm()->oops_begin()), p2i(nm()->oops_end()));
274 }
275
276 void ShenandoahNMethod::assert_no_oops(nmethod* nm, bool allow_dead) {
277 ShenandoahNMethodOopDetector detector;
278 nm->oops_do(&detector, allow_dead);
279 assert(detector.oops()->length() == 0, "Should not have oops");
280 }
281 #endif
282
283 ShenandoahNMethodTable::ShenandoahNMethodTable() :
284 _heap(ShenandoahHeap::heap()),
285 _size(minSize),
286 _index(0),
287 _iteration_in_progress(false) {
288 _array = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, _size, mtGC);
289 }
290
291 ShenandoahNMethodTable::~ShenandoahNMethodTable() {
292 assert(_array != NULL, "Sanity");
293 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, _array);
294 }
295
296 void ShenandoahNMethodTable::register_nmethod(nmethod* nm) {
297 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
298 assert(_index >= 0 && _index <= _size, "Sanity");
299
300 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
301 ShenandoahReentrantLocker data_locker(data != NULL ? data->lock() : NULL);
302
303 if (data != NULL) {
304 assert(contain(nm), "Must have been registered");
305 assert(nm == data->nm(), "must be same nmethod");
306 data->update();
307 } else {
308 data = ShenandoahNMethod::for_nmethod(nm);
309 if (data == NULL) {
310 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
311 "Only possible when concurrent class unloading is off");
312 return;
313 }
314 ShenandoahNMethod::attach_gc_data(nm, data);
315 ShenandoahLocker locker(&_lock);
316 log_register_nmethod(nm);
317 append(data);
318 }
319 // Disarm new nmethod
320 ShenandoahNMethod::disarm_nmethod(nm);
321 }
322
323 void ShenandoahNMethodTable::unregister_nmethod(nmethod* nm) {
324 assert_locked_or_safepoint(CodeCache_lock);
325
326 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
327 if (data == NULL) {
328 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
329 "Only possible when concurrent class unloading is off");
330 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/);
331 return;
332 }
333
334 if (Thread::current()->is_Code_cache_sweeper_thread()) {
335 wait_until_concurrent_iteration_done();
336 }
337 log_unregister_nmethod(nm);
338 ShenandoahLocker locker(&_lock);
339 assert(contain(nm), "Must have been registered");
340
341 ShenandoahReentrantLocker data_locker(data->lock());
342 data->mark_unregistered();
343 }
344
345 void ShenandoahNMethodTable::flush_nmethod(nmethod* nm) {
346 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
347 assert(Thread::current()->is_Code_cache_sweeper_thread(), "Must from Sweep thread");
348 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
349 assert(data != NULL || !ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
350 "Only possible when concurrent class unloading is off");
351 if (data == NULL) {
352 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/);
353 return;
354 }
355
356 // Can not alter the array when iteration is in progress
357 wait_until_concurrent_iteration_done();
358 log_flush_nmethod(nm);
359
360 ShenandoahLocker locker(&_lock);
361 int idx = index_of(nm);
362 assert(idx >= 0 && idx < _index, "Invalid index");
363 ShenandoahNMethod::attach_gc_data(nm, NULL);
364 remove(idx);
365 }
366
367 bool ShenandoahNMethodTable::contain(nmethod* nm) const {
368 return index_of(nm) != -1;
369 }
370
371 ShenandoahNMethod* ShenandoahNMethodTable::at(int index) const {
372 assert(index >= 0 && index < _index, "Out of bound");
373 return _array[index];
374 }
375
376 int ShenandoahNMethodTable::index_of(nmethod* nm) const {
377 for (int index = 0; index < length(); index ++) {
378 if (_array[index]->nm() == nm) {
379 return index;
380 }
381 }
382 return -1;
383 }
384
385 void ShenandoahNMethodTable::remove(int idx) {
386 shenandoah_assert_locked_or_safepoint(CodeCache_lock);
387 assert(!_iteration_in_progress, "Can not happen");
388 assert(_index >= 0 && _index <= _size, "Sanity");
389
390 assert(idx >= 0 && idx < _index, "Out of bound");
391 ShenandoahNMethod* snm = _array[idx];
392
393 _index --;
394 _array[idx] = _array[_index];
395
396 delete snm;
397 }
398
399 void ShenandoahNMethodTable::wait_until_concurrent_iteration_done() {
400 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
401 while (iteration_in_progress()) {
402 CodeCache_lock->wait_without_safepoint_check();
403 }
404 }
405
406 void ShenandoahNMethodTable::append(ShenandoahNMethod* snm) {
407 if (is_full()) {
408 int new_size = 2 * _size;
409 ShenandoahNMethod** old_table = _array;
410
411 // Rebuild table and replace current one
412 rebuild(new_size);
413
414 // An iteration is in progress over early snapshot,
415 // can not release the array until iteration is completed
416 if (!iteration_in_progress()) {
417 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, old_table);
418 }
419 }
420
421 _array[_index ++] = snm;
422 assert(_index >= 0 && _index <= _size, "Sanity");
423 }
424
425 void ShenandoahNMethodTable::rebuild(int size) {
426 ShenandoahNMethod** arr = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, size, mtGC);
427 for (int index = 0; index < _index; index ++) {
428 arr[index] = _array[index];
429 }
430 _array = arr;
431 _size = size;
432 }
433
434 ShenandoahNMethodTableSnapshot* ShenandoahNMethodTable::snapshot_for_iteration() {
435 assert(!iteration_in_progress(), "Already in progress");
436 _iteration_in_progress = true;
437
438 return new ShenandoahNMethodTableSnapshot(this);
439 }
440
441 void ShenandoahNMethodTable::finish_iteration(ShenandoahNMethodTableSnapshot* snapshot) {
442 assert(iteration_in_progress(), "Why we here?");
443 assert(snapshot != NULL, "No snapshot");
444 _iteration_in_progress = false;
445
446 // Table has been rebuilt during iteration, free old table
447 if (snapshot->_array != _array) {
448 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, snapshot->_array);
449 }
450 delete snapshot;
451 }
452
453 void ShenandoahNMethodTable::log_register_nmethod(nmethod* nm) {
454 LogTarget(Debug, gc, nmethod) log;
455 if (!log.is_enabled()) {
456 return;
457 }
458
459 ResourceMark rm;
460 log.print("Register NMethod: %s.%s [" PTR_FORMAT "] (%s)",
461 nm->method()->method_holder()->external_name(),
462 nm->method()->name()->as_C_string(),
463 p2i(nm),
464 nm->compiler_name());
465 }
466
467 void ShenandoahNMethodTable::log_unregister_nmethod(nmethod* nm) {
468 LogTarget(Debug, gc, nmethod) log;
469 if (!log.is_enabled()) {
470 return;
471 }
472
473 ResourceMark rm;
474 log.print("Unregister NMethod: %s.%s [" PTR_FORMAT "]",
475 nm->method()->method_holder()->external_name(),
476 nm->method()->name()->as_C_string(),
477 p2i(nm));
478 }
479
480 void ShenandoahNMethodTable::log_flush_nmethod(nmethod* nm) {
481 LogTarget(Debug, gc, nmethod) log;
482 if (!log.is_enabled()) {
483 return;
484 }
485
486 ResourceMark rm;
487 log.print("Flush NMethod: (" PTR_FORMAT ")", p2i(nm));
488 }
489
490 #ifdef ASSERT
491 void ShenandoahNMethodTable::assert_nmethods_alive_and_correct() {
492 assert_locked_or_safepoint(CodeCache_lock);
493
494 for (int index = 0; index < length(); index ++) {
495 ShenandoahNMethod* m = _array[index];
496 // Concurrent unloading may have dead nmethods to be cleaned by sweeper
497 if (m->is_unregistered()) continue;
498 m->assert_alive_and_correct();
499 }
500 }
501 #endif
502
503 ShenandoahNMethodTableSnapshot::ShenandoahNMethodTableSnapshot(ShenandoahNMethodTable* table) :
504 _heap(ShenandoahHeap::heap()), _table(table), _array(table->_array), _length(table->_index), _claimed(0) {
505 }
506
507 void ShenandoahNMethodTableSnapshot::concurrent_nmethods_do(NMethodClosure* cl) {
508 size_t stride = 256; // educated guess
509
510 ShenandoahNMethod** list = _array;
511 size_t max = (size_t)_length;
512 while (_claimed < max) {
513 size_t cur = Atomic::fetch_and_add(&_claimed, stride);
514 size_t start = cur;
515 size_t end = MIN2(cur + stride, max);
516 if (start >= max) break;
517
518 for (size_t idx = start; idx < end; idx++) {
519 ShenandoahNMethod* data = list[idx];
520 assert(data != NULL, "Should not be NULL");
521 if (!data->is_unregistered()) {
522 cl->do_nmethod(data->nm());
523 }
524 }
525 }
526 }
527
528 ShenandoahConcurrentNMethodIterator::ShenandoahConcurrentNMethodIterator(ShenandoahNMethodTable* table) :
529 _table(table), _table_snapshot(NULL) {
530 }
531
532 void ShenandoahConcurrentNMethodIterator::nmethods_do_begin() {
533 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
534 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
535 "Only for concurrent class unloading");
536 _table_snapshot = _table->snapshot_for_iteration();
537 }
538
539 void ShenandoahConcurrentNMethodIterator::nmethods_do(NMethodClosure* cl) {
540 assert(_table_snapshot != NULL, "Must first call nmethod_do_begin()");
541 _table_snapshot->concurrent_nmethods_do(cl);
542 }
543
544 void ShenandoahConcurrentNMethodIterator::nmethods_do_end() {
545 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
546 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
547 "Only for concurrent class unloading");
548 _table->finish_iteration(_table_snapshot);
549 CodeCache_lock->notify_all();
550 }