Tue, 27 Mar 2012 10:29:59 +0200
7156764: Remove unused size parameter from some CollectedHeap methods
Summary: Some minor cleanups
Reviewed-by: tonyp, jwilhelm
1 /*
2 * Copyright (c) 2001, 2012, 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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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).
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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25 #ifndef SHARE_VM_GC_INTERFACE_COLLECTEDHEAP_HPP
26 #define SHARE_VM_GC_INTERFACE_COLLECTEDHEAP_HPP
28 #include "gc_interface/gcCause.hpp"
29 #include "memory/allocation.hpp"
30 #include "memory/barrierSet.hpp"
31 #include "runtime/handles.hpp"
32 #include "runtime/perfData.hpp"
33 #include "runtime/safepoint.hpp"
34 #include "utilities/events.hpp"
36 // A "CollectedHeap" is an implementation of a java heap for HotSpot. This
37 // is an abstract class: there may be many different kinds of heaps. This
38 // class defines the functions that a heap must implement, and contains
39 // infrastructure common to all heaps.
41 class BarrierSet;
42 class ThreadClosure;
43 class AdaptiveSizePolicy;
44 class Thread;
45 class CollectorPolicy;
47 class GCMessage : public FormatBuffer<1024> {
48 public:
49 bool is_before;
51 public:
52 GCMessage() {}
53 };
55 class GCHeapLog : public EventLogBase<GCMessage> {
56 private:
57 void log_heap(bool before);
59 public:
60 GCHeapLog() : EventLogBase<GCMessage>("GC Heap History") {}
62 void log_heap_before() {
63 log_heap(true);
64 }
65 void log_heap_after() {
66 log_heap(false);
67 }
68 };
70 //
71 // CollectedHeap
72 // SharedHeap
73 // GenCollectedHeap
74 // G1CollectedHeap
75 // ParallelScavengeHeap
76 //
77 class CollectedHeap : public CHeapObj {
78 friend class VMStructs;
79 friend class IsGCActiveMark; // Block structured external access to _is_gc_active
80 friend class constantPoolCacheKlass; // allocate() method inserts is_conc_safe
82 #ifdef ASSERT
83 static int _fire_out_of_memory_count;
84 #endif
86 // Used for filler objects (static, but initialized in ctor).
87 static size_t _filler_array_max_size;
89 GCHeapLog* _gc_heap_log;
91 // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 is being used
92 bool _defer_initial_card_mark;
94 protected:
95 MemRegion _reserved;
96 BarrierSet* _barrier_set;
97 bool _is_gc_active;
98 uint _n_par_threads;
100 unsigned int _total_collections; // ... started
101 unsigned int _total_full_collections; // ... started
102 NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;)
103 NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;)
105 // Reason for current garbage collection. Should be set to
106 // a value reflecting no collection between collections.
107 GCCause::Cause _gc_cause;
108 GCCause::Cause _gc_lastcause;
109 PerfStringVariable* _perf_gc_cause;
110 PerfStringVariable* _perf_gc_lastcause;
112 // Constructor
113 CollectedHeap();
115 // Do common initializations that must follow instance construction,
116 // for example, those needing virtual calls.
117 // This code could perhaps be moved into initialize() but would
118 // be slightly more awkward because we want the latter to be a
119 // pure virtual.
120 void pre_initialize();
122 // Create a new tlab. All TLAB allocations must go through this.
123 virtual HeapWord* allocate_new_tlab(size_t size);
125 // Accumulate statistics on all tlabs.
126 virtual void accumulate_statistics_all_tlabs();
128 // Reinitialize tlabs before resuming mutators.
129 virtual void resize_all_tlabs();
131 // Allocate from the current thread's TLAB, with broken-out slow path.
132 inline static HeapWord* allocate_from_tlab(Thread* thread, size_t size);
133 static HeapWord* allocate_from_tlab_slow(Thread* thread, size_t size);
135 // Allocate an uninitialized block of the given size, or returns NULL if
136 // this is impossible.
137 inline static HeapWord* common_mem_allocate_noinit(size_t size, TRAPS);
139 // Like allocate_init, but the block returned by a successful allocation
140 // is guaranteed initialized to zeros.
141 inline static HeapWord* common_mem_allocate_init(size_t size, TRAPS);
143 // Same as common_mem version, except memory is allocated in the permanent area
144 // If there is no permanent area, revert to common_mem_allocate_noinit
145 inline static HeapWord* common_permanent_mem_allocate_noinit(size_t size, TRAPS);
147 // Same as common_mem version, except memory is allocated in the permanent area
148 // If there is no permanent area, revert to common_mem_allocate_init
149 inline static HeapWord* common_permanent_mem_allocate_init(size_t size, TRAPS);
151 // Helper functions for (VM) allocation.
152 inline static void post_allocation_setup_common(KlassHandle klass, HeapWord* obj);
153 inline static void post_allocation_setup_no_klass_install(KlassHandle klass,
154 HeapWord* objPtr);
156 inline static void post_allocation_setup_obj(KlassHandle klass, HeapWord* obj);
158 inline static void post_allocation_setup_array(KlassHandle klass,
159 HeapWord* obj, int length);
161 // Clears an allocated object.
162 inline static void init_obj(HeapWord* obj, size_t size);
164 // Filler object utilities.
165 static inline size_t filler_array_hdr_size();
166 static inline size_t filler_array_min_size();
168 DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);)
169 DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);)
171 // Fill with a single array; caller must ensure filler_array_min_size() <=
172 // words <= filler_array_max_size().
173 static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true);
175 // Fill with a single object (either an int array or a java.lang.Object).
176 static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true);
178 // Verification functions
179 virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size)
180 PRODUCT_RETURN;
181 virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size)
182 PRODUCT_RETURN;
183 debug_only(static void check_for_valid_allocation_state();)
185 public:
186 enum Name {
187 Abstract,
188 SharedHeap,
189 GenCollectedHeap,
190 ParallelScavengeHeap,
191 G1CollectedHeap
192 };
194 static inline size_t filler_array_max_size() {
195 return _filler_array_max_size;
196 }
198 virtual CollectedHeap::Name kind() const { return CollectedHeap::Abstract; }
200 /**
201 * Returns JNI error code JNI_ENOMEM if memory could not be allocated,
202 * and JNI_OK on success.
203 */
204 virtual jint initialize() = 0;
206 // In many heaps, there will be a need to perform some initialization activities
207 // after the Universe is fully formed, but before general heap allocation is allowed.
208 // This is the correct place to place such initialization methods.
209 virtual void post_initialize() = 0;
211 MemRegion reserved_region() const { return _reserved; }
212 address base() const { return (address)reserved_region().start(); }
214 // Future cleanup here. The following functions should specify bytes or
215 // heapwords as part of their signature.
216 virtual size_t capacity() const = 0;
217 virtual size_t used() const = 0;
219 // Return "true" if the part of the heap that allocates Java
220 // objects has reached the maximal committed limit that it can
221 // reach, without a garbage collection.
222 virtual bool is_maximal_no_gc() const = 0;
224 virtual size_t permanent_capacity() const = 0;
225 virtual size_t permanent_used() const = 0;
227 // Support for java.lang.Runtime.maxMemory(): return the maximum amount of
228 // memory that the vm could make available for storing 'normal' java objects.
229 // This is based on the reserved address space, but should not include space
230 // that the vm uses internally for bookkeeping or temporary storage (e.g.,
231 // perm gen space or, in the case of the young gen, one of the survivor
232 // spaces).
233 virtual size_t max_capacity() const = 0;
235 // Returns "TRUE" if "p" points into the reserved area of the heap.
236 bool is_in_reserved(const void* p) const {
237 return _reserved.contains(p);
238 }
240 bool is_in_reserved_or_null(const void* p) const {
241 return p == NULL || is_in_reserved(p);
242 }
244 // Returns "TRUE" iff "p" points into the committed areas of the heap.
245 // Since this method can be expensive in general, we restrict its
246 // use to assertion checking only.
247 virtual bool is_in(const void* p) const = 0;
249 bool is_in_or_null(const void* p) const {
250 return p == NULL || is_in(p);
251 }
253 // Let's define some terms: a "closed" subset of a heap is one that
254 //
255 // 1) contains all currently-allocated objects, and
256 //
257 // 2) is closed under reference: no object in the closed subset
258 // references one outside the closed subset.
259 //
260 // Membership in a heap's closed subset is useful for assertions.
261 // Clearly, the entire heap is a closed subset, so the default
262 // implementation is to use "is_in_reserved". But this may not be too
263 // liberal to perform useful checking. Also, the "is_in" predicate
264 // defines a closed subset, but may be too expensive, since "is_in"
265 // verifies that its argument points to an object head. The
266 // "closed_subset" method allows a heap to define an intermediate
267 // predicate, allowing more precise checking than "is_in_reserved" at
268 // lower cost than "is_in."
270 // One important case is a heap composed of disjoint contiguous spaces,
271 // such as the Garbage-First collector. Such heaps have a convenient
272 // closed subset consisting of the allocated portions of those
273 // contiguous spaces.
275 // Return "TRUE" iff the given pointer points into the heap's defined
276 // closed subset (which defaults to the entire heap).
277 virtual bool is_in_closed_subset(const void* p) const {
278 return is_in_reserved(p);
279 }
281 bool is_in_closed_subset_or_null(const void* p) const {
282 return p == NULL || is_in_closed_subset(p);
283 }
285 // XXX is_permanent() and is_in_permanent() should be better named
286 // to distinguish one from the other.
288 // Returns "TRUE" if "p" is allocated as "permanent" data.
289 // If the heap does not use "permanent" data, returns the same
290 // value is_in_reserved() would return.
291 // NOTE: this actually returns true if "p" is in reserved space
292 // for the space not that it is actually allocated (i.e. in committed
293 // space). If you need the more conservative answer use is_permanent().
294 virtual bool is_in_permanent(const void *p) const = 0;
297 #ifdef ASSERT
298 // Returns true if "p" is in the part of the
299 // heap being collected.
300 virtual bool is_in_partial_collection(const void *p) = 0;
301 #endif
303 bool is_in_permanent_or_null(const void *p) const {
304 return p == NULL || is_in_permanent(p);
305 }
307 // Returns "TRUE" if "p" is in the committed area of "permanent" data.
308 // If the heap does not use "permanent" data, returns the same
309 // value is_in() would return.
310 virtual bool is_permanent(const void *p) const = 0;
312 bool is_permanent_or_null(const void *p) const {
313 return p == NULL || is_permanent(p);
314 }
316 // An object is scavengable if its location may move during a scavenge.
317 // (A scavenge is a GC which is not a full GC.)
318 virtual bool is_scavengable(const void *p) = 0;
320 // Returns "TRUE" if "p" is a method oop in the
321 // current heap, with high probability. This predicate
322 // is not stable, in general.
323 bool is_valid_method(oop p) const;
325 void set_gc_cause(GCCause::Cause v) {
326 if (UsePerfData) {
327 _gc_lastcause = _gc_cause;
328 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause));
329 _perf_gc_cause->set_value(GCCause::to_string(v));
330 }
331 _gc_cause = v;
332 }
333 GCCause::Cause gc_cause() { return _gc_cause; }
335 // Number of threads currently working on GC tasks.
336 uint n_par_threads() { return _n_par_threads; }
338 // May be overridden to set additional parallelism.
339 virtual void set_par_threads(uint t) { _n_par_threads = t; };
341 // Preload classes into the shared portion of the heap, and then dump
342 // that data to a file so that it can be loaded directly by another
343 // VM (then terminate).
344 virtual void preload_and_dump(TRAPS) { ShouldNotReachHere(); }
346 // Allocate and initialize instances of Class
347 static oop Class_obj_allocate(KlassHandle klass, int size, KlassHandle real_klass, TRAPS);
349 // General obj/array allocation facilities.
350 inline static oop obj_allocate(KlassHandle klass, int size, TRAPS);
351 inline static oop array_allocate(KlassHandle klass, int size, int length, TRAPS);
352 inline static oop array_allocate_nozero(KlassHandle klass, int size, int length, TRAPS);
354 // Special obj/array allocation facilities.
355 // Some heaps may want to manage "permanent" data uniquely. These default
356 // to the general routines if the heap does not support such handling.
357 inline static oop permanent_obj_allocate(KlassHandle klass, int size, TRAPS);
358 // permanent_obj_allocate_no_klass_install() does not do the installation of
359 // the klass pointer in the newly created object (as permanent_obj_allocate()
360 // above does). This allows for a delay in the installation of the klass
361 // pointer that is needed during the create of klassKlass's. The
362 // method post_allocation_install_obj_klass() is used to install the
363 // klass pointer.
364 inline static oop permanent_obj_allocate_no_klass_install(KlassHandle klass,
365 int size,
366 TRAPS);
367 inline static void post_allocation_install_obj_klass(KlassHandle klass, oop obj);
368 inline static oop permanent_array_allocate(KlassHandle klass, int size, int length, TRAPS);
370 // Raw memory allocation facilities
371 // The obj and array allocate methods are covers for these methods.
372 // The permanent allocation method should default to mem_allocate if
373 // permanent memory isn't supported. mem_allocate() should never be
374 // called to allocate TLABs, only individual objects.
375 virtual HeapWord* mem_allocate(size_t size,
376 bool* gc_overhead_limit_was_exceeded) = 0;
377 virtual HeapWord* permanent_mem_allocate(size_t size) = 0;
379 // Utilities for turning raw memory into filler objects.
380 //
381 // min_fill_size() is the smallest region that can be filled.
382 // fill_with_objects() can fill arbitrary-sized regions of the heap using
383 // multiple objects. fill_with_object() is for regions known to be smaller
384 // than the largest array of integers; it uses a single object to fill the
385 // region and has slightly less overhead.
386 static size_t min_fill_size() {
387 return size_t(align_object_size(oopDesc::header_size()));
388 }
390 static void fill_with_objects(HeapWord* start, size_t words, bool zap = true);
392 static void fill_with_object(HeapWord* start, size_t words, bool zap = true);
393 static void fill_with_object(MemRegion region, bool zap = true) {
394 fill_with_object(region.start(), region.word_size(), zap);
395 }
396 static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) {
397 fill_with_object(start, pointer_delta(end, start), zap);
398 }
400 // Some heaps may offer a contiguous region for shared non-blocking
401 // allocation, via inlined code (by exporting the address of the top and
402 // end fields defining the extent of the contiguous allocation region.)
404 // This function returns "true" iff the heap supports this kind of
405 // allocation. (Default is "no".)
406 virtual bool supports_inline_contig_alloc() const {
407 return false;
408 }
409 // These functions return the addresses of the fields that define the
410 // boundaries of the contiguous allocation area. (These fields should be
411 // physically near to one another.)
412 virtual HeapWord** top_addr() const {
413 guarantee(false, "inline contiguous allocation not supported");
414 return NULL;
415 }
416 virtual HeapWord** end_addr() const {
417 guarantee(false, "inline contiguous allocation not supported");
418 return NULL;
419 }
421 // Some heaps may be in an unparseable state at certain times between
422 // collections. This may be necessary for efficient implementation of
423 // certain allocation-related activities. Calling this function before
424 // attempting to parse a heap ensures that the heap is in a parsable
425 // state (provided other concurrent activity does not introduce
426 // unparsability). It is normally expected, therefore, that this
427 // method is invoked with the world stopped.
428 // NOTE: if you override this method, make sure you call
429 // super::ensure_parsability so that the non-generational
430 // part of the work gets done. See implementation of
431 // CollectedHeap::ensure_parsability and, for instance,
432 // that of GenCollectedHeap::ensure_parsability().
433 // The argument "retire_tlabs" controls whether existing TLABs
434 // are merely filled or also retired, thus preventing further
435 // allocation from them and necessitating allocation of new TLABs.
436 virtual void ensure_parsability(bool retire_tlabs);
438 // Return an estimate of the maximum allocation that could be performed
439 // without triggering any collection or expansion activity. In a
440 // generational collector, for example, this is probably the largest
441 // allocation that could be supported (without expansion) in the youngest
442 // generation. It is "unsafe" because no locks are taken; the result
443 // should be treated as an approximation, not a guarantee, for use in
444 // heuristic resizing decisions.
445 virtual size_t unsafe_max_alloc() = 0;
447 // Section on thread-local allocation buffers (TLABs)
448 // If the heap supports thread-local allocation buffers, it should override
449 // the following methods:
450 // Returns "true" iff the heap supports thread-local allocation buffers.
451 // The default is "no".
452 virtual bool supports_tlab_allocation() const {
453 return false;
454 }
455 // The amount of space available for thread-local allocation buffers.
456 virtual size_t tlab_capacity(Thread *thr) const {
457 guarantee(false, "thread-local allocation buffers not supported");
458 return 0;
459 }
460 // An estimate of the maximum allocation that could be performed
461 // for thread-local allocation buffers without triggering any
462 // collection or expansion activity.
463 virtual size_t unsafe_max_tlab_alloc(Thread *thr) const {
464 guarantee(false, "thread-local allocation buffers not supported");
465 return 0;
466 }
468 // Can a compiler initialize a new object without store barriers?
469 // This permission only extends from the creation of a new object
470 // via a TLAB up to the first subsequent safepoint. If such permission
471 // is granted for this heap type, the compiler promises to call
472 // defer_store_barrier() below on any slow path allocation of
473 // a new object for which such initializing store barriers will
474 // have been elided.
475 virtual bool can_elide_tlab_store_barriers() const = 0;
477 // If a compiler is eliding store barriers for TLAB-allocated objects,
478 // there is probably a corresponding slow path which can produce
479 // an object allocated anywhere. The compiler's runtime support
480 // promises to call this function on such a slow-path-allocated
481 // object before performing initializations that have elided
482 // store barriers. Returns new_obj, or maybe a safer copy thereof.
483 virtual oop new_store_pre_barrier(JavaThread* thread, oop new_obj);
485 // Answers whether an initializing store to a new object currently
486 // allocated at the given address doesn't need a store
487 // barrier. Returns "true" if it doesn't need an initializing
488 // store barrier; answers "false" if it does.
489 virtual bool can_elide_initializing_store_barrier(oop new_obj) = 0;
491 // If a compiler is eliding store barriers for TLAB-allocated objects,
492 // we will be informed of a slow-path allocation by a call
493 // to new_store_pre_barrier() above. Such a call precedes the
494 // initialization of the object itself, and no post-store-barriers will
495 // be issued. Some heap types require that the barrier strictly follows
496 // the initializing stores. (This is currently implemented by deferring the
497 // barrier until the next slow-path allocation or gc-related safepoint.)
498 // This interface answers whether a particular heap type needs the card
499 // mark to be thus strictly sequenced after the stores.
500 virtual bool card_mark_must_follow_store() const = 0;
502 // If the CollectedHeap was asked to defer a store barrier above,
503 // this informs it to flush such a deferred store barrier to the
504 // remembered set.
505 virtual void flush_deferred_store_barrier(JavaThread* thread);
507 // Can a compiler elide a store barrier when it writes
508 // a permanent oop into the heap? Applies when the compiler
509 // is storing x to the heap, where x->is_perm() is true.
510 virtual bool can_elide_permanent_oop_store_barriers() const = 0;
512 // Does this heap support heap inspection (+PrintClassHistogram?)
513 virtual bool supports_heap_inspection() const = 0;
515 // Perform a collection of the heap; intended for use in implementing
516 // "System.gc". This probably implies as full a collection as the
517 // "CollectedHeap" supports.
518 virtual void collect(GCCause::Cause cause) = 0;
520 // This interface assumes that it's being called by the
521 // vm thread. It collects the heap assuming that the
522 // heap lock is already held and that we are executing in
523 // the context of the vm thread.
524 virtual void collect_as_vm_thread(GCCause::Cause cause) = 0;
526 // Returns the barrier set for this heap
527 BarrierSet* barrier_set() { return _barrier_set; }
529 // Returns "true" iff there is a stop-world GC in progress. (I assume
530 // that it should answer "false" for the concurrent part of a concurrent
531 // collector -- dld).
532 bool is_gc_active() const { return _is_gc_active; }
534 // Total number of GC collections (started)
535 unsigned int total_collections() const { return _total_collections; }
536 unsigned int total_full_collections() const { return _total_full_collections;}
538 // Increment total number of GC collections (started)
539 // Should be protected but used by PSMarkSweep - cleanup for 1.4.2
540 void increment_total_collections(bool full = false) {
541 _total_collections++;
542 if (full) {
543 increment_total_full_collections();
544 }
545 }
547 void increment_total_full_collections() { _total_full_collections++; }
549 // Return the AdaptiveSizePolicy for the heap.
550 virtual AdaptiveSizePolicy* size_policy() = 0;
552 // Return the CollectorPolicy for the heap
553 virtual CollectorPolicy* collector_policy() const = 0;
555 // Iterate over all the ref-containing fields of all objects, calling
556 // "cl.do_oop" on each. This includes objects in permanent memory.
557 virtual void oop_iterate(OopClosure* cl) = 0;
559 // Iterate over all objects, calling "cl.do_object" on each.
560 // This includes objects in permanent memory.
561 virtual void object_iterate(ObjectClosure* cl) = 0;
563 // Similar to object_iterate() except iterates only
564 // over live objects.
565 virtual void safe_object_iterate(ObjectClosure* cl) = 0;
567 // Behaves the same as oop_iterate, except only traverses
568 // interior pointers contained in permanent memory. If there
569 // is no permanent memory, does nothing.
570 virtual void permanent_oop_iterate(OopClosure* cl) = 0;
572 // Behaves the same as object_iterate, except only traverses
573 // object contained in permanent memory. If there is no
574 // permanent memory, does nothing.
575 virtual void permanent_object_iterate(ObjectClosure* cl) = 0;
577 // NOTE! There is no requirement that a collector implement these
578 // functions.
579 //
580 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
581 // each address in the (reserved) heap is a member of exactly
582 // one block. The defining characteristic of a block is that it is
583 // possible to find its size, and thus to progress forward to the next
584 // block. (Blocks may be of different sizes.) Thus, blocks may
585 // represent Java objects, or they might be free blocks in a
586 // free-list-based heap (or subheap), as long as the two kinds are
587 // distinguishable and the size of each is determinable.
589 // Returns the address of the start of the "block" that contains the
590 // address "addr". We say "blocks" instead of "object" since some heaps
591 // may not pack objects densely; a chunk may either be an object or a
592 // non-object.
593 virtual HeapWord* block_start(const void* addr) const = 0;
595 // Requires "addr" to be the start of a chunk, and returns its size.
596 // "addr + size" is required to be the start of a new chunk, or the end
597 // of the active area of the heap.
598 virtual size_t block_size(const HeapWord* addr) const = 0;
600 // Requires "addr" to be the start of a block, and returns "TRUE" iff
601 // the block is an object.
602 virtual bool block_is_obj(const HeapWord* addr) const = 0;
604 // Returns the longest time (in ms) that has elapsed since the last
605 // time that any part of the heap was examined by a garbage collection.
606 virtual jlong millis_since_last_gc() = 0;
608 // Perform any cleanup actions necessary before allowing a verification.
609 virtual void prepare_for_verify() = 0;
611 // Generate any dumps preceding or following a full gc
612 void pre_full_gc_dump();
613 void post_full_gc_dump();
615 // Print heap information on the given outputStream.
616 virtual void print_on(outputStream* st) const = 0;
617 // The default behavior is to call print_on() on tty.
618 virtual void print() const {
619 print_on(tty);
620 }
621 // Print more detailed heap information on the given
622 // outputStream. The default behaviour is to call print_on(). It is
623 // up to each subclass to override it and add any additional output
624 // it needs.
625 virtual void print_extended_on(outputStream* st) const {
626 print_on(st);
627 }
629 // Print all GC threads (other than the VM thread)
630 // used by this heap.
631 virtual void print_gc_threads_on(outputStream* st) const = 0;
632 // The default behavior is to call print_gc_threads_on() on tty.
633 void print_gc_threads() {
634 print_gc_threads_on(tty);
635 }
636 // Iterator for all GC threads (other than VM thread)
637 virtual void gc_threads_do(ThreadClosure* tc) const = 0;
639 // Print any relevant tracing info that flags imply.
640 // Default implementation does nothing.
641 virtual void print_tracing_info() const = 0;
643 // If PrintHeapAtGC is set call the appropriate routi
644 void print_heap_before_gc() {
645 if (PrintHeapAtGC) {
646 Universe::print_heap_before_gc();
647 }
648 if (_gc_heap_log != NULL) {
649 _gc_heap_log->log_heap_before();
650 }
651 }
652 void print_heap_after_gc() {
653 if (PrintHeapAtGC) {
654 Universe::print_heap_after_gc();
655 }
656 if (_gc_heap_log != NULL) {
657 _gc_heap_log->log_heap_after();
658 }
659 }
661 // Heap verification
662 virtual void verify(bool allow_dirty, bool silent, VerifyOption option) = 0;
664 // Non product verification and debugging.
665 #ifndef PRODUCT
666 // Support for PromotionFailureALot. Return true if it's time to cause a
667 // promotion failure. The no-argument version uses
668 // this->_promotion_failure_alot_count as the counter.
669 inline bool promotion_should_fail(volatile size_t* count);
670 inline bool promotion_should_fail();
672 // Reset the PromotionFailureALot counters. Should be called at the end of a
673 // GC in which promotion failure ocurred.
674 inline void reset_promotion_should_fail(volatile size_t* count);
675 inline void reset_promotion_should_fail();
676 #endif // #ifndef PRODUCT
678 #ifdef ASSERT
679 static int fired_fake_oom() {
680 return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt);
681 }
682 #endif
684 public:
685 // This is a convenience method that is used in cases where
686 // the actual number of GC worker threads is not pertinent but
687 // only whether there more than 0. Use of this method helps
688 // reduce the occurrence of ParallelGCThreads to uses where the
689 // actual number may be germane.
690 static bool use_parallel_gc_threads() { return ParallelGCThreads > 0; }
692 /////////////// Unit tests ///////////////
694 NOT_PRODUCT(static void test_is_in();)
695 };
697 // Class to set and reset the GC cause for a CollectedHeap.
699 class GCCauseSetter : StackObj {
700 CollectedHeap* _heap;
701 GCCause::Cause _previous_cause;
702 public:
703 GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) {
704 assert(SafepointSynchronize::is_at_safepoint(),
705 "This method manipulates heap state without locking");
706 _heap = heap;
707 _previous_cause = _heap->gc_cause();
708 _heap->set_gc_cause(cause);
709 }
711 ~GCCauseSetter() {
712 assert(SafepointSynchronize::is_at_safepoint(),
713 "This method manipulates heap state without locking");
714 _heap->set_gc_cause(_previous_cause);
715 }
716 };
718 #endif // SHARE_VM_GC_INTERFACE_COLLECTEDHEAP_HPP