1 /*
2 * Copyright (c) 2001, 2018, 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
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7 * published by the Free Software Foundation.
8 *
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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.
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23 */
24
25 #ifndef SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP
26 #define SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP
27
28 #include "gc/shared/gcCause.hpp"
29 #include "gc/shared/gcWhen.hpp"
30 #include "memory/allocation.hpp"
31 #include "runtime/handles.hpp"
32 #include "runtime/perfData.hpp"
33 #include "runtime/safepoint.hpp"
34 #include "utilities/debug.hpp"
35 #include "utilities/events.hpp"
36 #include "utilities/formatBuffer.hpp"
37 #include "utilities/growableArray.hpp"
38
39 // A "CollectedHeap" is an implementation of a java heap for HotSpot. This
40 // is an abstract class: there may be many different kinds of heaps. This
41 // class defines the functions that a heap must implement, and contains
42 // infrastructure common to all heaps.
43
44 class AdaptiveSizePolicy;
45 class BarrierSet;
46 class CollectorPolicy;
47 class GCHeapSummary;
48 class GCTimer;
49 class GCTracer;
50 class GCMemoryManager;
51 class MemoryPool;
52 class MetaspaceSummary;
53 class SoftRefPolicy;
54 class Thread;
55 class ThreadClosure;
56 class VirtualSpaceSummary;
57 class WorkGang;
58 class nmethod;
59
60 class GCMessage : public FormatBuffer<1024> {
61 public:
62 bool is_before;
63
64 public:
65 GCMessage() {}
66 };
67
68 class CollectedHeap;
69
70 class GCHeapLog : public EventLogBase<GCMessage> {
71 private:
72 void log_heap(CollectedHeap* heap, bool before);
73
74 public:
75 GCHeapLog() : EventLogBase<GCMessage>("GC Heap History") {}
76
77 void log_heap_before(CollectedHeap* heap) {
78 log_heap(heap, true);
79 }
80 void log_heap_after(CollectedHeap* heap) {
81 log_heap(heap, false);
82 }
83 };
84
85 //
86 // CollectedHeap
87 // GenCollectedHeap
88 // SerialHeap
89 // CMSHeap
90 // G1CollectedHeap
91 // ParallelScavengeHeap
92 //
93 class CollectedHeap : public CHeapObj<mtInternal> {
94 friend class VMStructs;
95 friend class JVMCIVMStructs;
96 friend class IsGCActiveMark; // Block structured external access to _is_gc_active
97
98 private:
99 #ifdef ASSERT
100 static int _fire_out_of_memory_count;
101 #endif
102
103 GCHeapLog* _gc_heap_log;
104
105 MemRegion _reserved;
106
107 protected:
108 bool _is_gc_active;
109
110 // Used for filler objects (static, but initialized in ctor).
111 static size_t _filler_array_max_size;
112
113 unsigned int _total_collections; // ... started
114 unsigned int _total_full_collections; // ... started
115 NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;)
116 NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;)
117
118 // Reason for current garbage collection. Should be set to
119 // a value reflecting no collection between collections.
120 GCCause::Cause _gc_cause;
121 GCCause::Cause _gc_lastcause;
122 PerfStringVariable* _perf_gc_cause;
123 PerfStringVariable* _perf_gc_lastcause;
124
125 // Constructor
126 CollectedHeap();
127
128 // Create a new tlab. All TLAB allocations must go through this.
129 // To allow more flexible TLAB allocations min_size specifies
130 // the minimum size needed, while requested_size is the requested
131 // size based on ergonomics. The actually allocated size will be
132 // returned in actual_size.
133 virtual HeapWord* allocate_new_tlab(size_t min_size,
134 size_t requested_size,
135 size_t* actual_size);
136
137 // Accumulate statistics on all tlabs.
138 virtual void accumulate_statistics_all_tlabs();
139
140 // Reinitialize tlabs before resuming mutators.
141 virtual void resize_all_tlabs();
142
143 // Allocate from the current thread's TLAB, with broken-out slow path.
144 inline static HeapWord* allocate_from_tlab(Klass* klass, Thread* thread, size_t size);
145 static HeapWord* allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size);
146
147 // Allocate an uninitialized block of the given size, or returns NULL if
148 // this is impossible.
149 inline static HeapWord* common_mem_allocate_noinit(Klass* klass, size_t size, TRAPS);
150
151 // Like allocate_init, but the block returned by a successful allocation
152 // is guaranteed initialized to zeros.
153 inline static HeapWord* common_mem_allocate_init(Klass* klass, size_t size, TRAPS);
154
155 // Helper functions for (VM) allocation.
156 inline static void post_allocation_setup_common(Klass* klass, HeapWord* obj);
157 inline static void post_allocation_setup_no_klass_install(Klass* klass,
158 HeapWord* objPtr);
159
160 inline static void post_allocation_setup_obj(Klass* klass, HeapWord* obj, int size);
161
162 inline static void post_allocation_setup_array(Klass* klass,
163 HeapWord* obj, int length);
164
165 inline static void post_allocation_setup_class(Klass* klass, HeapWord* obj, int size);
166
167 // Clears an allocated object.
168 inline static void init_obj(HeapWord* obj, size_t size);
169
170 // Filler object utilities.
171 static inline size_t filler_array_hdr_size();
172 static inline size_t filler_array_min_size();
173
174 DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);)
175 DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);)
176
177 // Fill with a single array; caller must ensure filler_array_min_size() <=
178 // words <= filler_array_max_size().
179 static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true);
180
181 // Fill with a single object (either an int array or a java.lang.Object).
182 static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true);
183
184 virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer);
185
186 // Verification functions
187 virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size)
188 PRODUCT_RETURN;
189 virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size)
190 PRODUCT_RETURN;
191 debug_only(static void check_for_valid_allocation_state();)
192
193 public:
194 enum Name {
195 None,
196 Serial,
197 Parallel,
198 CMS,
199 G1
200 };
201
202 static inline size_t filler_array_max_size() {
203 return _filler_array_max_size;
204 }
205
206 virtual Name kind() const = 0;
207
208 virtual const char* name() const = 0;
209
210 /**
211 * Returns JNI error code JNI_ENOMEM if memory could not be allocated,
212 * and JNI_OK on success.
213 */
214 virtual jint initialize() = 0;
215
216 // In many heaps, there will be a need to perform some initialization activities
217 // after the Universe is fully formed, but before general heap allocation is allowed.
218 // This is the correct place to place such initialization methods.
219 virtual void post_initialize();
220
221 // Stop any onging concurrent work and prepare for exit.
222 virtual void stop() {}
223
224 // Stop and resume concurrent GC threads interfering with safepoint operations
225 virtual void safepoint_synchronize_begin() {}
226 virtual void safepoint_synchronize_end() {}
227
228 void initialize_reserved_region(HeapWord *start, HeapWord *end);
229 MemRegion reserved_region() const { return _reserved; }
230 address base() const { return (address)reserved_region().start(); }
231
232 virtual size_t capacity() const = 0;
233 virtual size_t used() const = 0;
234
235 // Return "true" if the part of the heap that allocates Java
236 // objects has reached the maximal committed limit that it can
237 // reach, without a garbage collection.
238 virtual bool is_maximal_no_gc() const = 0;
239
240 // Support for java.lang.Runtime.maxMemory(): return the maximum amount of
241 // memory that the vm could make available for storing 'normal' java objects.
242 // This is based on the reserved address space, but should not include space
243 // that the vm uses internally for bookkeeping or temporary storage
244 // (e.g., in the case of the young gen, one of the survivor
245 // spaces).
246 virtual size_t max_capacity() const = 0;
247
248 // Returns "TRUE" if "p" points into the reserved area of the heap.
249 bool is_in_reserved(const void* p) const {
250 return _reserved.contains(p);
251 }
252
253 bool is_in_reserved_or_null(const void* p) const {
254 return p == NULL || is_in_reserved(p);
255 }
256
257 // Returns "TRUE" iff "p" points into the committed areas of the heap.
258 // This method can be expensive so avoid using it in performance critical
259 // code.
260 virtual bool is_in(const void* p) const = 0;
261
262 DEBUG_ONLY(bool is_in_or_null(const void* p) const { return p == NULL || is_in(p); })
263
264 // Let's define some terms: a "closed" subset of a heap is one that
265 //
266 // 1) contains all currently-allocated objects, and
267 //
268 // 2) is closed under reference: no object in the closed subset
269 // references one outside the closed subset.
270 //
271 // Membership in a heap's closed subset is useful for assertions.
272 // Clearly, the entire heap is a closed subset, so the default
273 // implementation is to use "is_in_reserved". But this may not be too
274 // liberal to perform useful checking. Also, the "is_in" predicate
275 // defines a closed subset, but may be too expensive, since "is_in"
276 // verifies that its argument points to an object head. The
277 // "closed_subset" method allows a heap to define an intermediate
278 // predicate, allowing more precise checking than "is_in_reserved" at
279 // lower cost than "is_in."
280
281 // One important case is a heap composed of disjoint contiguous spaces,
282 // such as the Garbage-First collector. Such heaps have a convenient
283 // closed subset consisting of the allocated portions of those
284 // contiguous spaces.
285
286 // Return "TRUE" iff the given pointer points into the heap's defined
287 // closed subset (which defaults to the entire heap).
288 virtual bool is_in_closed_subset(const void* p) const {
289 return is_in_reserved(p);
290 }
291
292 bool is_in_closed_subset_or_null(const void* p) const {
293 return p == NULL || is_in_closed_subset(p);
294 }
295
296 void set_gc_cause(GCCause::Cause v) {
297 if (UsePerfData) {
298 _gc_lastcause = _gc_cause;
299 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause));
300 _perf_gc_cause->set_value(GCCause::to_string(v));
301 }
302 _gc_cause = v;
303 }
304 GCCause::Cause gc_cause() { return _gc_cause; }
305
306 // General obj/array allocation facilities.
307 inline static oop obj_allocate(Klass* klass, int size, TRAPS);
308 inline static oop array_allocate(Klass* klass, int size, int length, TRAPS);
309 inline static oop array_allocate_nozero(Klass* klass, int size, int length, TRAPS);
310 inline static oop class_allocate(Klass* klass, int size, TRAPS);
311
312 // Raw memory allocation facilities
313 // The obj and array allocate methods are covers for these methods.
314 // mem_allocate() should never be
315 // called to allocate TLABs, only individual objects.
316 virtual HeapWord* mem_allocate(size_t size,
317 bool* gc_overhead_limit_was_exceeded) = 0;
318
319 // Utilities for turning raw memory into filler objects.
320 //
321 // min_fill_size() is the smallest region that can be filled.
322 // fill_with_objects() can fill arbitrary-sized regions of the heap using
323 // multiple objects. fill_with_object() is for regions known to be smaller
324 // than the largest array of integers; it uses a single object to fill the
325 // region and has slightly less overhead.
326 static size_t min_fill_size() {
327 return size_t(align_object_size(oopDesc::header_size()));
328 }
329
330 static void fill_with_objects(HeapWord* start, size_t words, bool zap = true);
331
332 static void fill_with_object(HeapWord* start, size_t words, bool zap = true);
333 static void fill_with_object(MemRegion region, bool zap = true) {
334 fill_with_object(region.start(), region.word_size(), zap);
335 }
336 static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) {
337 fill_with_object(start, pointer_delta(end, start), zap);
338 }
339
340 // Return the address "addr" aligned by "alignment_in_bytes" if such
341 // an address is below "end". Return NULL otherwise.
342 inline static HeapWord* align_allocation_or_fail(HeapWord* addr,
343 HeapWord* end,
344 unsigned short alignment_in_bytes);
345
346 // Some heaps may offer a contiguous region for shared non-blocking
347 // allocation, via inlined code (by exporting the address of the top and
348 // end fields defining the extent of the contiguous allocation region.)
349
350 // This function returns "true" iff the heap supports this kind of
351 // allocation. (Default is "no".)
352 virtual bool supports_inline_contig_alloc() const {
353 return false;
354 }
355 // These functions return the addresses of the fields that define the
356 // boundaries of the contiguous allocation area. (These fields should be
357 // physically near to one another.)
358 virtual HeapWord* volatile* top_addr() const {
359 guarantee(false, "inline contiguous allocation not supported");
360 return NULL;
361 }
362 virtual HeapWord** end_addr() const {
363 guarantee(false, "inline contiguous allocation not supported");
364 return NULL;
365 }
366
367 // Some heaps may be in an unparseable state at certain times between
368 // collections. This may be necessary for efficient implementation of
369 // certain allocation-related activities. Calling this function before
370 // attempting to parse a heap ensures that the heap is in a parsable
371 // state (provided other concurrent activity does not introduce
372 // unparsability). It is normally expected, therefore, that this
373 // method is invoked with the world stopped.
374 // NOTE: if you override this method, make sure you call
375 // super::ensure_parsability so that the non-generational
376 // part of the work gets done. See implementation of
377 // CollectedHeap::ensure_parsability and, for instance,
378 // that of GenCollectedHeap::ensure_parsability().
379 // The argument "retire_tlabs" controls whether existing TLABs
380 // are merely filled or also retired, thus preventing further
381 // allocation from them and necessitating allocation of new TLABs.
382 virtual void ensure_parsability(bool retire_tlabs);
383
384 // Section on thread-local allocation buffers (TLABs)
385 // If the heap supports thread-local allocation buffers, it should override
386 // the following methods:
387 // Returns "true" iff the heap supports thread-local allocation buffers.
388 // The default is "no".
389 virtual bool supports_tlab_allocation() const = 0;
390
391 // The amount of space available for thread-local allocation buffers.
392 virtual size_t tlab_capacity(Thread *thr) const = 0;
393
394 // The amount of used space for thread-local allocation buffers for the given thread.
395 virtual size_t tlab_used(Thread *thr) const = 0;
396
397 virtual size_t max_tlab_size() const;
398
399 // An estimate of the maximum allocation that could be performed
400 // for thread-local allocation buffers without triggering any
401 // collection or expansion activity.
402 virtual size_t unsafe_max_tlab_alloc(Thread *thr) const {
403 guarantee(false, "thread-local allocation buffers not supported");
404 return 0;
405 }
406
407 // Perform a collection of the heap; intended for use in implementing
408 // "System.gc". This probably implies as full a collection as the
409 // "CollectedHeap" supports.
410 virtual void collect(GCCause::Cause cause) = 0;
411
412 // Perform a full collection
413 virtual void do_full_collection(bool clear_all_soft_refs) = 0;
414
415 // This interface assumes that it's being called by the
416 // vm thread. It collects the heap assuming that the
417 // heap lock is already held and that we are executing in
418 // the context of the vm thread.
419 virtual void collect_as_vm_thread(GCCause::Cause cause);
420
421 virtual MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
422 size_t size,
423 Metaspace::MetadataType mdtype);
424
425 // Returns "true" iff there is a stop-world GC in progress. (I assume
426 // that it should answer "false" for the concurrent part of a concurrent
427 // collector -- dld).
428 bool is_gc_active() const { return _is_gc_active; }
429
430 // Total number of GC collections (started)
431 unsigned int total_collections() const { return _total_collections; }
432 unsigned int total_full_collections() const { return _total_full_collections;}
433
434 // Increment total number of GC collections (started)
435 // Should be protected but used by PSMarkSweep - cleanup for 1.4.2
436 void increment_total_collections(bool full = false) {
437 _total_collections++;
438 if (full) {
439 increment_total_full_collections();
440 }
441 }
442
443 void increment_total_full_collections() { _total_full_collections++; }
444
445 // Return the CollectorPolicy for the heap
446 virtual CollectorPolicy* collector_policy() const = 0;
447
448 // Return the SoftRefPolicy for the heap;
449 virtual SoftRefPolicy* soft_ref_policy() = 0;
450
451 virtual GrowableArray<GCMemoryManager*> memory_managers() = 0;
452 virtual GrowableArray<MemoryPool*> memory_pools() = 0;
453
454 // Iterate over all objects, calling "cl.do_object" on each.
455 virtual void object_iterate(ObjectClosure* cl) = 0;
456
457 // Similar to object_iterate() except iterates only
458 // over live objects.
459 virtual void safe_object_iterate(ObjectClosure* cl) = 0;
460
461 // NOTE! There is no requirement that a collector implement these
462 // functions.
463 //
464 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
465 // each address in the (reserved) heap is a member of exactly
466 // one block. The defining characteristic of a block is that it is
467 // possible to find its size, and thus to progress forward to the next
468 // block. (Blocks may be of different sizes.) Thus, blocks may
469 // represent Java objects, or they might be free blocks in a
470 // free-list-based heap (or subheap), as long as the two kinds are
471 // distinguishable and the size of each is determinable.
472
473 // Returns the address of the start of the "block" that contains the
474 // address "addr". We say "blocks" instead of "object" since some heaps
475 // may not pack objects densely; a chunk may either be an object or a
476 // non-object.
477 virtual HeapWord* block_start(const void* addr) const = 0;
478
479 // Requires "addr" to be the start of a chunk, and returns its size.
480 // "addr + size" is required to be the start of a new chunk, or the end
481 // of the active area of the heap.
482 virtual size_t block_size(const HeapWord* addr) const = 0;
483
484 // Requires "addr" to be the start of a block, and returns "TRUE" iff
485 // the block is an object.
486 virtual bool block_is_obj(const HeapWord* addr) const = 0;
487
488 // Returns the longest time (in ms) that has elapsed since the last
489 // time that any part of the heap was examined by a garbage collection.
490 virtual jlong millis_since_last_gc() = 0;
491
492 // Perform any cleanup actions necessary before allowing a verification.
493 virtual void prepare_for_verify() = 0;
494
495 // Generate any dumps preceding or following a full gc
496 private:
497 void full_gc_dump(GCTimer* timer, bool before);
498
499 virtual void initialize_serviceability() = 0;
500
501 public:
502 void pre_full_gc_dump(GCTimer* timer);
503 void post_full_gc_dump(GCTimer* timer);
504
505 virtual VirtualSpaceSummary create_heap_space_summary();
506 GCHeapSummary create_heap_summary();
507
508 MetaspaceSummary create_metaspace_summary();
509
510 // Print heap information on the given outputStream.
511 virtual void print_on(outputStream* st) const = 0;
512 // The default behavior is to call print_on() on tty.
513 virtual void print() const {
514 print_on(tty);
515 }
516 // Print more detailed heap information on the given
517 // outputStream. The default behavior is to call print_on(). It is
518 // up to each subclass to override it and add any additional output
519 // it needs.
520 virtual void print_extended_on(outputStream* st) const {
521 print_on(st);
522 }
523
524 virtual void print_on_error(outputStream* st) const;
525
526 // Print all GC threads (other than the VM thread)
527 // used by this heap.
528 virtual void print_gc_threads_on(outputStream* st) const = 0;
529 // The default behavior is to call print_gc_threads_on() on tty.
530 void print_gc_threads() {
531 print_gc_threads_on(tty);
532 }
533 // Iterator for all GC threads (other than VM thread)
534 virtual void gc_threads_do(ThreadClosure* tc) const = 0;
535
536 // Print any relevant tracing info that flags imply.
537 // Default implementation does nothing.
538 virtual void print_tracing_info() const = 0;
539
540 void print_heap_before_gc();
541 void print_heap_after_gc();
542
543 // An object is scavengable if its location may move during a scavenge.
544 // (A scavenge is a GC which is not a full GC.)
545 virtual bool is_scavengable(oop obj) = 0;
546 // Registering and unregistering an nmethod (compiled code) with the heap.
547 // Override with specific mechanism for each specialized heap type.
548 virtual void register_nmethod(nmethod* nm) {}
549 virtual void unregister_nmethod(nmethod* nm) {}
550 virtual void verify_nmethod(nmethod* nmethod) {}
551
552 void trace_heap_before_gc(const GCTracer* gc_tracer);
553 void trace_heap_after_gc(const GCTracer* gc_tracer);
554
555 // Heap verification
556 virtual void verify(VerifyOption option) = 0;
557
558 // Return true if concurrent phase control (via
559 // request_concurrent_phase_control) is supported by this collector.
560 // The default implementation returns false.
561 virtual bool supports_concurrent_phase_control() const;
562
563 // Return a NULL terminated array of concurrent phase names provided
564 // by this collector. Supports Whitebox testing. These are the
565 // names recognized by request_concurrent_phase(). The default
566 // implementation returns an array of one NULL element.
567 virtual const char* const* concurrent_phases() const;
568
569 // Request the collector enter the indicated concurrent phase, and
570 // wait until it does so. Supports WhiteBox testing. Only one
571 // request may be active at a time. Phases are designated by name;
572 // the set of names and their meaning is GC-specific. Once the
573 // requested phase has been reached, the collector will attempt to
574 // avoid transitioning to a new phase until a new request is made.
575 // [Note: A collector might not be able to remain in a given phase.
576 // For example, a full collection might cancel an in-progress
577 // concurrent collection.]
578 //
579 // Returns true when the phase is reached. Returns false for an
580 // unknown phase. The default implementation returns false.
581 virtual bool request_concurrent_phase(const char* phase);
582
583 // Provides a thread pool to SafepointSynchronize to use
584 // for parallel safepoint cleanup.
585 // GCs that use a GC worker thread pool may want to share
586 // it for use during safepoint cleanup. This is only possible
587 // if the GC can pause and resume concurrent work (e.g. G1
588 // concurrent marking) for an intermittent non-GC safepoint.
589 // If this method returns NULL, SafepointSynchronize will
590 // perform cleanup tasks serially in the VMThread.
591 virtual WorkGang* get_safepoint_workers() { return NULL; }
592
593 // Support for object pinning. This is used by JNI Get*Critical()
594 // and Release*Critical() family of functions. If supported, the GC
595 // must guarantee that pinned objects never move.
596 virtual bool supports_object_pinning() const;
597 virtual oop pin_object(JavaThread* thread, oop obj);
598 virtual void unpin_object(JavaThread* thread, oop obj);
599
600 virtual bool is_oop(oop object) const;
601
602 // Non product verification and debugging.
603 #ifndef PRODUCT
604 // Support for PromotionFailureALot. Return true if it's time to cause a
605 // promotion failure. The no-argument version uses
606 // this->_promotion_failure_alot_count as the counter.
607 bool promotion_should_fail(volatile size_t* count);
608 bool promotion_should_fail();
609
610 // Reset the PromotionFailureALot counters. Should be called at the end of a
611 // GC in which promotion failure occurred.
612 void reset_promotion_should_fail(volatile size_t* count);
613 void reset_promotion_should_fail();
614 #endif // #ifndef PRODUCT
615
616 #ifdef ASSERT
617 static int fired_fake_oom() {
618 return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt);
619 }
620 #endif
621 };
622
623 // Class to set and reset the GC cause for a CollectedHeap.
624
625 class GCCauseSetter : StackObj {
626 CollectedHeap* _heap;
627 GCCause::Cause _previous_cause;
628 public:
629 GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) {
630 _heap = heap;
631 _previous_cause = _heap->gc_cause();
632 _heap->set_gc_cause(cause);
633 }
634
635 ~GCCauseSetter() {
636 _heap->set_gc_cause(_previous_cause);
637 }
638 };
639
640 #endif // SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP
--- EOF ---