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 if (r->oop_value() != NULL) {
149 // Non-NULL immediate oop found. NULL oops can safely be
150 // ignored since the method will be re-registered if they
151 // are later patched to be non-NULL.
152 oops.push(r->oop_addr());
153 }
154 }
155 }
156
157 ShenandoahNMethod* ShenandoahNMethod::for_nmethod(nmethod* nm) {
158 ResourceMark rm;
159 bool non_immediate_oops = false;
160 GrowableArray<oop*> oops;
161
162 detect_reloc_oops(nm, oops, non_immediate_oops);
163
164 // No embedded oops
165 if(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading() &&
166 oops.is_empty() && nm->oops_begin() >= nm->oops_end()) {
167 return NULL;
168 }
169
170 return new ShenandoahNMethod(nm, oops, non_immediate_oops);
171 }
172
173 void ShenandoahNMethod::heal_nmethod(nmethod* nm) {
174 assert(ShenandoahHeap::heap()->is_concurrent_root_in_progress(), "Only this phase");
175 ShenandoahNMethod* data = gc_data(nm);
176 assert(data != NULL, "Sanity");
177 assert(data->lock()->owned_by_self(), "Must hold the lock");
178
179 ShenandoahEvacOOMScope evac_scope;
180 ShenandoahEvacuateUpdateRootsClosure cl;
181 data->oops_do(&cl, true /*fix relocation*/);
182 }
183
184 #ifdef ASSERT
185 void ShenandoahNMethod::assert_alive_and_correct() {
186 assert(_nm->is_alive(), "only alive nmethods here");
187 ShenandoahHeap* heap = ShenandoahHeap::heap();
188 for (int c = 0; c < _oops_count; c++) {
189 oop *loc = _oops[c];
190 assert(_nm->code_contains((address) loc) || _nm->oops_contains(loc), "nmethod should contain the oop*");
191 oop o = RawAccess<>::oop_load(loc);
192 shenandoah_assert_correct_except(loc, o, o == NULL || heap->is_full_gc_move_in_progress());
193 }
194
195 oop* const begin = _nm->oops_begin();
196 oop* const end = _nm->oops_end();
197 for (oop* p = begin; p < end; p++) {
198 if (*p != Universe::non_oop_word()) {
199 oop o = RawAccess<>::oop_load(p);
200 shenandoah_assert_correct_except(p, o, o == NULL || heap->is_full_gc_move_in_progress());
201 }
202 }
203 }
204
205 class ShenandoahNMethodOopDetector : public OopClosure {
206 private:
207 ResourceMark rm; // For growable array allocation below.
208 GrowableArray<oop*> _oops;
209
210 public:
211 ShenandoahNMethodOopDetector() : _oops(10) {};
212
213 void do_oop(oop* o) {
214 _oops.append(o);
215 }
216 void do_oop(narrowOop* o) {
217 fatal("NMethods should not have compressed oops embedded.");
218 }
219
220 GrowableArray<oop*>* oops() {
221 return &_oops;
222 }
223
224 bool has_oops() {
225 return !_oops.is_empty();
226 }
227 };
228
229 void ShenandoahNMethod::assert_same_oops(bool allow_dead) {
230 ShenandoahNMethodOopDetector detector;
231 nm()->oops_do(&detector, allow_dead);
232
233 GrowableArray<oop*>* oops = detector.oops();
234
235 assert(oops->length() == oop_count(), "Must match");
236
237 for (int index = 0; index < _oops_count; index ++) {
238 assert(oops->contains(_oops[index]), "Must contain this oop");
239 }
240
241 for (oop* p = nm()->oops_begin(); p < nm()->oops_end(); p ++) {
242 assert(oops->contains(p), "Must contain this oop");
243 }
244 }
245
246 void ShenandoahNMethod::assert_no_oops(nmethod* nm, bool allow_dead) {
247 ShenandoahNMethodOopDetector detector;
248 nm->oops_do(&detector, allow_dead);
249 assert(detector.oops()->length() == 0, "Should not have oops");
250 }
251 #endif
252
253 ShenandoahNMethodTable::ShenandoahNMethodTable() :
254 _heap(ShenandoahHeap::heap()),
255 _size(minSize),
256 _index(0),
257 _iteration_in_progress(false) {
258 _array = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, _size, mtGC);
259 }
260
261 ShenandoahNMethodTable::~ShenandoahNMethodTable() {
262 assert(_array != NULL, "Sanity");
263 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, _array);
264 }
265
266 void ShenandoahNMethodTable::register_nmethod(nmethod* nm) {
267 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
268 assert(_index >= 0 && _index <= _size, "Sanity");
269
270 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
271 ShenandoahReentrantLocker data_locker(data != NULL ? data->lock() : NULL);
272
273 if (data != NULL) {
274 assert(contain(nm), "Must have been registered");
275 data->update();
276 } else {
277 data = ShenandoahNMethod::for_nmethod(nm);
278 if (data == NULL) {
279 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
280 "Only possible when concurrent class unloading is off");
281 return;
282 }
283 ShenandoahNMethod::attach_gc_data(nm, data);
284 ShenandoahLocker locker(&_lock);
285 log_register_nmethod(nm);
286 append(data);
287 }
288 // Disarm new nmethod
289 ShenandoahNMethod::disarm_nmethod(nm);
290 }
291
292 void ShenandoahNMethodTable::unregister_nmethod(nmethod* nm) {
293 assert_locked_or_safepoint(CodeCache_lock);
294
295 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
296 if (data == NULL) {
297 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
298 "Only possible when concurrent class unloading is off");
299 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/);
300 return;
301 }
302
303 if (Thread::current()->is_Code_cache_sweeper_thread()) {
304 wait_until_concurrent_iteration_done();
305 }
306 log_unregister_nmethod(nm);
307 ShenandoahLocker locker(&_lock);
308 assert(contain(nm), "Must have been registered");
309
310 ShenandoahReentrantLocker data_locker(data->lock());
311 data->mark_unregistered();
312 }
313
314 void ShenandoahNMethodTable::flush_nmethod(nmethod* nm) {
315 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
316 assert(Thread::current()->is_Code_cache_sweeper_thread(), "Must from Sweep thread");
317 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
318 assert(data != NULL || !ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
319 "Only possible when concurrent class unloading is off");
320 if (data == NULL) {
321 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/);
322 return;
323 }
324
325 // Can not alter the array when iteration is in progress
326 wait_until_concurrent_iteration_done();
327 log_flush_nmethod(nm);
328
329 ShenandoahLocker locker(&_lock);
330 int idx = index_of(nm);
331 assert(idx >= 0 && idx < _index, "Invalid index");
332 ShenandoahNMethod::attach_gc_data(nm, NULL);
333 remove(idx);
334 }
335
336 bool ShenandoahNMethodTable::contain(nmethod* nm) const {
337 return index_of(nm) != -1;
338 }
339
340 ShenandoahNMethod* ShenandoahNMethodTable::at(int index) const {
341 assert(index >= 0 && index < _index, "Out of bound");
342 return _array[index];
343 }
344
345 int ShenandoahNMethodTable::index_of(nmethod* nm) const {
346 for (int index = 0; index < length(); index ++) {
347 if (_array[index]->nm() == nm) {
348 return index;
349 }
350 }
351 return -1;
352 }
353
354 void ShenandoahNMethodTable::remove(int idx) {
355 shenandoah_assert_locked_or_safepoint(CodeCache_lock);
356 assert(!_iteration_in_progress, "Can not happen");
357 assert(_index >= 0 && _index <= _size, "Sanity");
358
359 assert(idx >= 0 && idx < _index, "Out of bound");
360 ShenandoahNMethod* snm = _array[idx];
361
362 _index --;
363 _array[idx] = _array[_index];
364
365 delete snm;
366 }
367
368 void ShenandoahNMethodTable::wait_until_concurrent_iteration_done() {
369 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
370 while (iteration_in_progress()) {
371 CodeCache_lock->wait_without_safepoint_check();
372 }
373 }
374
375 void ShenandoahNMethodTable::append(ShenandoahNMethod* snm) {
376 if (is_full()) {
377 int new_size = 2 * _size;
378 ShenandoahNMethod** old_table = _array;
379
380 // Rebuild table and replace current one
381 rebuild(new_size);
382
383 // An iteration is in progress over early snapshot,
384 // can not release the array until iteration is completed
385 if (!iteration_in_progress()) {
386 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, old_table);
387 }
388 }
389
390 _array[_index ++] = snm;
391 assert(_index >= 0 && _index <= _size, "Sanity");
392 }
393
394 void ShenandoahNMethodTable::rebuild(int size) {
395 ShenandoahNMethod** arr = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, size, mtGC);
396 for (int index = 0; index < _index; index ++) {
397 arr[index] = _array[index];
398 }
399 _array = arr;
400 _size = size;
401 }
402
403 ShenandoahNMethodTableSnapshot* ShenandoahNMethodTable::snapshot_for_iteration() {
404 assert(!iteration_in_progress(), "Already in progress");
405 _iteration_in_progress = true;
406
407 return new ShenandoahNMethodTableSnapshot(this);
408 }
409
410 void ShenandoahNMethodTable::finish_iteration(ShenandoahNMethodTableSnapshot* snapshot) {
411 assert(iteration_in_progress(), "Why we here?");
412 assert(snapshot != NULL, "No snapshot");
413 _iteration_in_progress = false;
414
415 // Table has been rebuilt during iteration, free old table
416 if (snapshot->_array != _array) {
417 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, snapshot->_array);
418 }
419 delete snapshot;
420 }
421
422 void ShenandoahNMethodTable::log_register_nmethod(nmethod* nm) {
423 LogTarget(Debug, gc, nmethod) log;
424 if (!log.is_enabled()) {
425 return;
426 }
427
428 ResourceMark rm;
429 log.print("Register NMethod: %s.%s [" PTR_FORMAT "] (%s)",
430 nm->method()->method_holder()->external_name(),
431 nm->method()->name()->as_C_string(),
432 p2i(nm),
433 nm->compiler_name());
434 }
435
436 void ShenandoahNMethodTable::log_unregister_nmethod(nmethod* nm) {
437 LogTarget(Debug, gc, nmethod) log;
438 if (!log.is_enabled()) {
439 return;
440 }
441
442 ResourceMark rm;
443 log.print("Unregister NMethod: %s.%s [" PTR_FORMAT "]",
444 nm->method()->method_holder()->external_name(),
445 nm->method()->name()->as_C_string(),
446 p2i(nm));
447 }
448
449 void ShenandoahNMethodTable::log_flush_nmethod(nmethod* nm) {
450 LogTarget(Debug, gc, nmethod) log;
451 if (!log.is_enabled()) {
452 return;
453 }
454
455 ResourceMark rm;
456 log.print("Flush NMethod: (" PTR_FORMAT ")", p2i(nm));
457 }
458
459 #ifdef ASSERT
460 void ShenandoahNMethodTable::assert_nmethods_alive_and_correct() {
461 assert_locked_or_safepoint(CodeCache_lock);
462
463 for (int index = 0; index < length(); index ++) {
464 ShenandoahNMethod* m = _array[index];
465 // Concurrent unloading may have dead nmethods to be cleaned by sweeper
466 if (m->is_unregistered()) continue;
467 m->assert_alive_and_correct();
468 }
469 }
470 #endif
471
472 ShenandoahNMethodTableSnapshot::ShenandoahNMethodTableSnapshot(ShenandoahNMethodTable* table) :
473 _heap(ShenandoahHeap::heap()), _table(table), _array(table->_array), _length(table->_index), _claimed(0) {
474 }
475
476 void ShenandoahNMethodTableSnapshot::concurrent_nmethods_do(NMethodClosure* cl) {
477 size_t stride = 256; // educated guess
478
479 ShenandoahNMethod** list = _array;
480 size_t max = (size_t)_length;
481 while (_claimed < max) {
482 size_t cur = Atomic::add(&_claimed, stride) - stride;
483 size_t start = cur;
484 size_t end = MIN2(cur + stride, max);
485 if (start >= max) break;
486
487 for (size_t idx = start; idx < end; idx++) {
488 ShenandoahNMethod* data = list[idx];
489 assert(data != NULL, "Should not be NULL");
490 if (!data->is_unregistered()) {
491 cl->do_nmethod(data->nm());
492 }
493 }
494 }
495 }
496
497 ShenandoahConcurrentNMethodIterator::ShenandoahConcurrentNMethodIterator(ShenandoahNMethodTable* table) :
498 _table(table), _table_snapshot(NULL) {
499 }
500
501 void ShenandoahConcurrentNMethodIterator::nmethods_do_begin() {
502 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
503 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
504 "Only for concurrent class unloading");
505 _table_snapshot = _table->snapshot_for_iteration();
506 }
507
508 void ShenandoahConcurrentNMethodIterator::nmethods_do(NMethodClosure* cl) {
509 assert(_table_snapshot != NULL, "Must first call nmethod_do_begin()");
510 _table_snapshot->concurrent_nmethods_do(cl);
511 }
512
513 void ShenandoahConcurrentNMethodIterator::nmethods_do_end() {
514 assert(CodeCache_lock->owned_by_self(), "Lock must be held");
515 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(),
516 "Only for concurrent class unloading");
517 _table->finish_iteration(_table_snapshot);
518 CodeCache_lock->notify_all();
519 }