1 /*
2 * Copyright (c) 1997, 2014, 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
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "gc_implementation/shared/markSweep.inline.hpp"
29 #include "gc_interface/collectedHeap.hpp"
30 #include "gc_interface/collectedHeap.inline.hpp"
31 #include "memory/genCollectedHeap.hpp"
32 #include "memory/genOopClosures.inline.hpp"
33 #include "memory/specialized_oop_closures.hpp"
34 #include "oops/instanceRefKlass.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "utilities/preserveException.hpp"
37 #include "utilities/macros.hpp"
38 #if INCLUDE_ALL_GCS
39 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
40 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
41 #include "gc_implementation/g1/g1RemSet.inline.hpp"
42 #include "gc_implementation/g1/heapRegionManager.inline.hpp"
43 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
44 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
45 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
46 #endif // INCLUDE_ALL_GCS
47
48 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
49
50 template <class T>
51 void specialized_oop_follow_contents(InstanceRefKlass* ref, oop obj) {
52 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
53 T heap_oop = oopDesc::load_heap_oop(referent_addr);
54 debug_only(
55 if(TraceReferenceGC && PrintGCDetails) {
56 gclog_or_tty->print_cr("InstanceRefKlass::oop_follow_contents " INTPTR_FORMAT, (void *)obj);
57 }
58 )
59 if (!oopDesc::is_null(heap_oop)) {
60 oop referent = oopDesc::decode_heap_oop_not_null(heap_oop);
61 if (!referent->is_gc_marked() &&
62 MarkSweep::ref_processor()->discover_reference(obj, ref->reference_type())) {
63 // reference was discovered, referent will be traversed later
64 ref->InstanceKlass::oop_follow_contents(obj);
65 debug_only(
66 if(TraceReferenceGC && PrintGCDetails) {
67 gclog_or_tty->print_cr(" Non NULL enqueued " INTPTR_FORMAT, (void *)obj);
68 }
69 )
70 return;
71 } else {
72 // treat referent as normal oop
73 debug_only(
74 if(TraceReferenceGC && PrintGCDetails) {
75 gclog_or_tty->print_cr(" Non NULL normal " INTPTR_FORMAT, (void *)obj);
76 }
77 )
78 MarkSweep::mark_and_push(referent_addr);
79 }
80 }
81 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
82 if (ReferenceProcessor::pending_list_uses_discovered_field()) {
83 // Treat discovered as normal oop, if ref is not "active",
84 // i.e. if next is non-NULL.
85 T next_oop = oopDesc::load_heap_oop(next_addr);
86 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
87 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
88 debug_only(
89 if(TraceReferenceGC && PrintGCDetails) {
90 gclog_or_tty->print_cr(" Process discovered as normal "
91 INTPTR_FORMAT, discovered_addr);
92 }
93 )
94 MarkSweep::mark_and_push(discovered_addr);
95 }
96 } else {
97 #ifdef ASSERT
98 // In the case of older JDKs which do not use the discovered
99 // field for the pending list, an inactive ref (next != NULL)
100 // must always have a NULL discovered field.
101 oop next = oopDesc::load_decode_heap_oop(next_addr);
102 oop discovered = java_lang_ref_Reference::discovered(obj);
103 assert(oopDesc::is_null(next) || oopDesc::is_null(discovered),
104 err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL discovered field",
105 (oopDesc*)obj));
106 #endif
107 }
108 // treat next as normal oop. next is a link in the reference queue.
109 debug_only(
110 if(TraceReferenceGC && PrintGCDetails) {
111 gclog_or_tty->print_cr(" Process next as normal " INTPTR_FORMAT, next_addr);
112 }
113 )
114 MarkSweep::mark_and_push(next_addr);
115 ref->InstanceKlass::oop_follow_contents(obj);
116 }
117
118 void InstanceRefKlass::oop_follow_contents(oop obj) {
119 if (UseCompressedOops) {
120 specialized_oop_follow_contents<narrowOop>(this, obj);
121 } else {
122 specialized_oop_follow_contents<oop>(this, obj);
123 }
124 }
125
126 #if INCLUDE_ALL_GCS
127 template <class T>
128 void specialized_oop_follow_contents(InstanceRefKlass* ref,
129 ParCompactionManager* cm,
130 oop obj) {
131 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
132 T heap_oop = oopDesc::load_heap_oop(referent_addr);
133 debug_only(
134 if(TraceReferenceGC && PrintGCDetails) {
135 gclog_or_tty->print_cr("InstanceRefKlass::oop_follow_contents " INTPTR_FORMAT, (void *)obj);
136 }
137 )
138 if (!oopDesc::is_null(heap_oop)) {
139 oop referent = oopDesc::decode_heap_oop_not_null(heap_oop);
140 if (PSParallelCompact::mark_bitmap()->is_unmarked(referent) &&
141 PSParallelCompact::ref_processor()->
142 discover_reference(obj, ref->reference_type())) {
143 // reference already enqueued, referent will be traversed later
144 ref->InstanceKlass::oop_follow_contents(cm, obj);
145 debug_only(
146 if(TraceReferenceGC && PrintGCDetails) {
147 gclog_or_tty->print_cr(" Non NULL enqueued " INTPTR_FORMAT, (void *)obj);
148 }
149 )
150 return;
151 } else {
152 // treat referent as normal oop
153 debug_only(
154 if(TraceReferenceGC && PrintGCDetails) {
155 gclog_or_tty->print_cr(" Non NULL normal " INTPTR_FORMAT, (void *)obj);
156 }
157 )
158 PSParallelCompact::mark_and_push(cm, referent_addr);
159 }
160 }
161 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
162 if (ReferenceProcessor::pending_list_uses_discovered_field()) {
163 // Treat discovered as normal oop, if ref is not "active",
164 // i.e. if next is non-NULL.
165 T next_oop = oopDesc::load_heap_oop(next_addr);
166 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
167 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
168 debug_only(
169 if(TraceReferenceGC && PrintGCDetails) {
170 gclog_or_tty->print_cr(" Process discovered as normal "
171 INTPTR_FORMAT, discovered_addr);
172 }
173 )
174 PSParallelCompact::mark_and_push(cm, discovered_addr);
175 }
176 } else {
177 #ifdef ASSERT
178 // In the case of older JDKs which do not use the discovered
179 // field for the pending list, an inactive ref (next != NULL)
180 // must always have a NULL discovered field.
181 T next = oopDesc::load_heap_oop(next_addr);
182 oop discovered = java_lang_ref_Reference::discovered(obj);
183 assert(oopDesc::is_null(next) || oopDesc::is_null(discovered),
184 err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL discovered field",
185 (oopDesc*)obj));
186 #endif
187 }
188 PSParallelCompact::mark_and_push(cm, next_addr);
189 ref->InstanceKlass::oop_follow_contents(cm, obj);
190 }
191
192 void InstanceRefKlass::oop_follow_contents(ParCompactionManager* cm,
193 oop obj) {
194 if (UseCompressedOops) {
195 specialized_oop_follow_contents<narrowOop>(this, cm, obj);
196 } else {
197 specialized_oop_follow_contents<oop>(this, cm, obj);
198 }
199 }
200 #endif // INCLUDE_ALL_GCS
201
202 #ifdef ASSERT
203 template <class T> void trace_reference_gc(const char *s, oop obj,
204 T* referent_addr,
205 T* next_addr,
206 T* discovered_addr) {
207 if(TraceReferenceGC && PrintGCDetails) {
208 gclog_or_tty->print_cr("%s obj " INTPTR_FORMAT, s, (address)obj);
209 gclog_or_tty->print_cr(" referent_addr/* " INTPTR_FORMAT " / "
210 INTPTR_FORMAT, referent_addr,
211 referent_addr ?
212 (address)oopDesc::load_decode_heap_oop(referent_addr) : NULL);
213 gclog_or_tty->print_cr(" next_addr/* " INTPTR_FORMAT " / "
214 INTPTR_FORMAT, next_addr,
215 next_addr ? (address)oopDesc::load_decode_heap_oop(next_addr) : NULL);
216 gclog_or_tty->print_cr(" discovered_addr/* " INTPTR_FORMAT " / "
217 INTPTR_FORMAT, discovered_addr,
218 discovered_addr ?
219 (address)oopDesc::load_decode_heap_oop(discovered_addr) : NULL);
220 }
221 }
222 #endif
223
224 template <class T> void specialized_oop_adjust_pointers(InstanceRefKlass *ref, oop obj) {
225 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
226 MarkSweep::adjust_pointer(referent_addr);
227 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
228 MarkSweep::adjust_pointer(next_addr);
229 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
230 MarkSweep::adjust_pointer(discovered_addr);
231 debug_only(trace_reference_gc("InstanceRefKlass::oop_adjust_pointers", obj,
232 referent_addr, next_addr, discovered_addr);)
233 }
234
235 int InstanceRefKlass::oop_adjust_pointers(oop obj) {
236 int size = size_helper();
237 InstanceKlass::oop_adjust_pointers(obj);
238
239 if (UseCompressedOops) {
240 specialized_oop_adjust_pointers<narrowOop>(this, obj);
241 } else {
242 specialized_oop_adjust_pointers<oop>(this, obj);
243 }
244 return size;
245 }
246
247 #define InstanceRefKlass_SPECIALIZED_OOP_ITERATE(T, nv_suffix, contains) \
248 T* disc_addr = (T*)java_lang_ref_Reference::discovered_addr(obj); \
249 if (closure->apply_to_weak_ref_discovered_field()) { \
250 closure->do_oop##nv_suffix(disc_addr); \
251 } \
252 \
253 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj); \
254 T heap_oop = oopDesc::load_heap_oop(referent_addr); \
255 ReferenceProcessor* rp = closure->_ref_processor; \
256 if (!oopDesc::is_null(heap_oop)) { \
257 oop referent = oopDesc::decode_heap_oop_not_null(heap_oop); \
258 if (!referent->is_gc_marked() && (rp != NULL) && \
259 rp->discover_reference(obj, reference_type())) { \
260 return size; \
261 } else if (contains(referent_addr)) { \
262 /* treat referent as normal oop */ \
263 closure->do_oop##nv_suffix(referent_addr); \
264 } \
265 } \
266 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj); \
267 if (ReferenceProcessor::pending_list_uses_discovered_field()) { \
268 T next_oop = oopDesc::load_heap_oop(next_addr); \
269 /* Treat discovered as normal oop, if ref is not "active" (next non-NULL) */\
270 if (!oopDesc::is_null(next_oop) && contains(disc_addr)) { \
271 /* i.e. ref is not "active" */ \
272 debug_only( \
273 if(TraceReferenceGC && PrintGCDetails) { \
274 gclog_or_tty->print_cr(" Process discovered as normal " \
275 INTPTR_FORMAT, disc_addr); \
276 } \
277 ) \
278 closure->do_oop##nv_suffix(disc_addr); \
279 } \
280 } else { \
281 /* In the case of older JDKs which do not use the discovered field for */ \
282 /* the pending list, an inactive ref (next != NULL) must always have a */ \
283 /* NULL discovered field. */ \
284 debug_only( \
285 T next_oop = oopDesc::load_heap_oop(next_addr); \
286 T disc_oop = oopDesc::load_heap_oop(disc_addr); \
287 assert(oopDesc::is_null(next_oop) || oopDesc::is_null(disc_oop), \
288 err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL" \
289 "discovered field", (oopDesc*)obj)); \
290 ) \
291 } \
292 /* treat next as normal oop */ \
293 if (contains(next_addr)) { \
294 closure->do_oop##nv_suffix(next_addr); \
295 } \
296 return size; \
297
298
299 template <class T> bool contains(T *t) { return true; }
300
301 // Macro to define InstanceRefKlass::oop_oop_iterate for virtual/nonvirtual for
302 // all closures. Macros calling macros above for each oop size.
303
304 #define InstanceRefKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
305 \
306 int InstanceRefKlass:: \
307 oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
308 /* Get size before changing pointers */ \
309 int size = InstanceKlass::oop_oop_iterate##nv_suffix(obj, closure); \
310 \
311 if (UseCompressedOops) { \
312 InstanceRefKlass_SPECIALIZED_OOP_ITERATE(narrowOop, nv_suffix, contains); \
313 } else { \
314 InstanceRefKlass_SPECIALIZED_OOP_ITERATE(oop, nv_suffix, contains); \
315 } \
316 }
317
318 #if INCLUDE_ALL_GCS
319 #define InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
320 \
321 int InstanceRefKlass:: \
322 oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) { \
323 /* Get size before changing pointers */ \
324 int size = InstanceKlass::oop_oop_iterate_backwards##nv_suffix(obj, closure); \
325 \
326 if (UseCompressedOops) { \
327 InstanceRefKlass_SPECIALIZED_OOP_ITERATE(narrowOop, nv_suffix, contains); \
328 } else { \
329 InstanceRefKlass_SPECIALIZED_OOP_ITERATE(oop, nv_suffix, contains); \
330 } \
331 }
332 #endif // INCLUDE_ALL_GCS
333
334
335 #define InstanceRefKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
336 \
337 int InstanceRefKlass:: \
338 oop_oop_iterate##nv_suffix##_m(oop obj, \
339 OopClosureType* closure, \
340 MemRegion mr) { \
341 int size = InstanceKlass::oop_oop_iterate##nv_suffix##_m(obj, closure, mr); \
342 if (UseCompressedOops) { \
343 InstanceRefKlass_SPECIALIZED_OOP_ITERATE(narrowOop, nv_suffix, mr.contains); \
344 } else { \
345 InstanceRefKlass_SPECIALIZED_OOP_ITERATE(oop, nv_suffix, mr.contains); \
346 } \
347 }
348
349 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_DEFN)
350 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_DEFN)
351 #if INCLUDE_ALL_GCS
352 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
353 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
354 #endif // INCLUDE_ALL_GCS
355 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_DEFN_m)
356 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_DEFN_m)
357
358 #if INCLUDE_ALL_GCS
359 template <class T>
360 void specialized_oop_push_contents(InstanceRefKlass *ref,
361 PSPromotionManager* pm, oop obj) {
362 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
363 if (PSScavenge::should_scavenge(referent_addr)) {
364 ReferenceProcessor* rp = PSScavenge::reference_processor();
365 if (rp->discover_reference(obj, ref->reference_type())) {
366 // reference already enqueued, referent and next will be traversed later
367 ref->InstanceKlass::oop_push_contents(pm, obj);
368 return;
369 } else {
370 // treat referent as normal oop
371 pm->claim_or_forward_depth(referent_addr);
372 }
373 }
374 // Treat discovered as normal oop, if ref is not "active",
375 // i.e. if next is non-NULL.
376 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
377 if (ReferenceProcessor::pending_list_uses_discovered_field()) {
378 T next_oop = oopDesc::load_heap_oop(next_addr);
379 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
380 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
381 debug_only(
382 if(TraceReferenceGC && PrintGCDetails) {
383 gclog_or_tty->print_cr(" Process discovered as normal "
384 INTPTR_FORMAT, discovered_addr);
385 }
386 )
387 if (PSScavenge::should_scavenge(discovered_addr)) {
388 pm->claim_or_forward_depth(discovered_addr);
389 }
390 }
391 } else {
392 #ifdef ASSERT
393 // In the case of older JDKs which do not use the discovered
394 // field for the pending list, an inactive ref (next != NULL)
395 // must always have a NULL discovered field.
396 oop next = oopDesc::load_decode_heap_oop(next_addr);
397 oop discovered = java_lang_ref_Reference::discovered(obj);
398 assert(oopDesc::is_null(next) || oopDesc::is_null(discovered),
399 err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL discovered field",
400 (oopDesc*)obj));
401 #endif
402 }
403
404 // Treat next as normal oop; next is a link in the reference queue.
405 if (PSScavenge::should_scavenge(next_addr)) {
406 pm->claim_or_forward_depth(next_addr);
407 }
408 ref->InstanceKlass::oop_push_contents(pm, obj);
409 }
410
411 void InstanceRefKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
412 if (UseCompressedOops) {
413 specialized_oop_push_contents<narrowOop>(this, pm, obj);
414 } else {
415 specialized_oop_push_contents<oop>(this, pm, obj);
416 }
417 }
418
419 template <class T>
420 void specialized_oop_update_pointers(InstanceRefKlass *ref,
421 ParCompactionManager* cm, oop obj) {
422 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
423 PSParallelCompact::adjust_pointer(referent_addr);
424 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
425 PSParallelCompact::adjust_pointer(next_addr);
426 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
427 PSParallelCompact::adjust_pointer(discovered_addr);
428 debug_only(trace_reference_gc("InstanceRefKlass::oop_update_ptrs", obj,
429 referent_addr, next_addr, discovered_addr);)
430 }
431
432 int InstanceRefKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
433 InstanceKlass::oop_update_pointers(cm, obj);
434 if (UseCompressedOops) {
435 specialized_oop_update_pointers<narrowOop>(this, cm, obj);
436 } else {
437 specialized_oop_update_pointers<oop>(this, cm, obj);
438 }
439 return size_helper();
440 }
441 #endif // INCLUDE_ALL_GCS
442
443 void InstanceRefKlass::update_nonstatic_oop_maps(Klass* k) {
444 // Clear the nonstatic oop-map entries corresponding to referent
445 // and nextPending field. They are treated specially by the
446 // garbage collector.
447 // The discovered field is used only by the garbage collector
448 // and is also treated specially.
449 InstanceKlass* ik = InstanceKlass::cast(k);
450
451 // Check that we have the right class
452 debug_only(static bool first_time = true);
453 assert(k == SystemDictionary::Reference_klass() && first_time,
454 "Invalid update of maps");
455 debug_only(first_time = false);
456 assert(ik->nonstatic_oop_map_count() == 1, "just checking");
457
458 OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
459
460 // Check that the current map is (2,4) - currently points at field with
461 // offset 2 (words) and has 4 map entries.
462 debug_only(int offset = java_lang_ref_Reference::referent_offset);
463 debug_only(unsigned int count = ((java_lang_ref_Reference::discovered_offset -
464 java_lang_ref_Reference::referent_offset)/heapOopSize) + 1);
465
466 if (UseSharedSpaces) {
467 assert(map->offset() == java_lang_ref_Reference::queue_offset &&
468 map->count() == 1, "just checking");
469 } else {
470 assert(map->offset() == offset && map->count() == count,
471 "just checking");
472
473 // Update map to (3,1) - point to offset of 3 (words) with 1 map entry.
474 map->set_offset(java_lang_ref_Reference::queue_offset);
475 map->set_count(1);
476 }
477 }
478
479
480 // Verification
481
482 void InstanceRefKlass::oop_verify_on(oop obj, outputStream* st) {
483 InstanceKlass::oop_verify_on(obj, st);
484 // Verify referent field
485 oop referent = java_lang_ref_Reference::referent(obj);
486
487 // We should make this general to all heaps
488 GenCollectedHeap* gch = NULL;
489 if (Universe::heap()->kind() == CollectedHeap::GenCollectedHeap)
490 gch = GenCollectedHeap::heap();
491
492 if (referent != NULL) {
493 guarantee(referent->is_oop(), "referent field heap failed");
494 }
495 // Verify next field
496 oop next = java_lang_ref_Reference::next(obj);
497 if (next != NULL) {
498 guarantee(next->is_oop(), "next field verify failed");
499 guarantee(next->is_instanceRef(), "next field verify failed");
500 }
501 }
502
503 bool InstanceRefKlass::owns_pending_list_lock(JavaThread* thread) {
504 if (java_lang_ref_Reference::pending_list_lock() == NULL) return false;
505 Handle h_lock(thread, java_lang_ref_Reference::pending_list_lock());
506 return ObjectSynchronizer::current_thread_holds_lock(thread, h_lock);
507 }
508
509 void InstanceRefKlass::acquire_pending_list_lock(BasicLock *pending_list_basic_lock) {
510 // we may enter this with pending exception set
511 PRESERVE_EXCEPTION_MARK; // exceptions are never thrown, needed for TRAPS argument
512
513 // Create a HandleMark in case we retry a GC multiple times.
514 // Each time we attempt the GC, we allocate the handle below
515 // to hold the pending list lock. We want to free this handle.
516 HandleMark hm;
517
518 Handle h_lock(THREAD, java_lang_ref_Reference::pending_list_lock());
519 ObjectSynchronizer::fast_enter(h_lock, pending_list_basic_lock, false, THREAD);
520 assert(ObjectSynchronizer::current_thread_holds_lock(
521 JavaThread::current(), h_lock),
522 "Locking should have succeeded");
523 if (HAS_PENDING_EXCEPTION) CLEAR_PENDING_EXCEPTION;
524 }
525
526 void InstanceRefKlass::release_and_notify_pending_list_lock(
527 BasicLock *pending_list_basic_lock) {
528 // we may enter this with pending exception set
529 PRESERVE_EXCEPTION_MARK; // exceptions are never thrown, needed for TRAPS argument
530
531 // Create a HandleMark in case we retry a GC multiple times.
532 // Each time we attempt the GC, we allocate the handle below
533 // to hold the pending list lock. We want to free this handle.
534 HandleMark hm;
535
536 Handle h_lock(THREAD, java_lang_ref_Reference::pending_list_lock());
537 assert(ObjectSynchronizer::current_thread_holds_lock(
538 JavaThread::current(), h_lock),
539 "Lock should be held");
540 // Notify waiters on pending lists lock if there is any reference.
541 if (java_lang_ref_Reference::pending_list() != NULL) {
542 ObjectSynchronizer::notifyall(h_lock, THREAD);
543 }
544 ObjectSynchronizer::fast_exit(h_lock(), pending_list_basic_lock, THREAD);
545 if (HAS_PENDING_EXCEPTION) CLEAR_PENDING_EXCEPTION;
546 }