/* * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP #include "gc_implementation/g1/g1AllocationContext.hpp" #include "gc_implementation/g1/g1BlockOffsetTable.hpp" #include "gc_implementation/g1/g1_specialized_oop_closures.hpp" #include "gc_implementation/g1/heapRegionType.hpp" #include "gc_implementation/g1/survRateGroup.hpp" #include "gc_implementation/shared/ageTable.hpp" #include "gc_implementation/shared/spaceDecorator.hpp" #include "memory/space.inline.hpp" #include "memory/watermark.hpp" #include "utilities/macros.hpp" #include "gc_implementation/g1/g1HeapRegionTraceType.hpp" // A HeapRegion is the smallest piece of a G1CollectedHeap that // can be collected independently. // NOTE: Although a HeapRegion is a Space, its // Space::initDirtyCardClosure method must not be called. // The problem is that the existence of this method breaks // the independence of barrier sets from remembered sets. // The solution is to remove this method from the definition // of a Space. class HeapRegionRemSet; class HeapRegionRemSetIterator; class HeapRegion; class HeapRegionSetBase; class nmethod; #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]" #define HR_FORMAT_PARAMS(_hr_) \ (_hr_)->hrm_index(), \ (_hr_)->get_short_type_str(), \ p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end()) // sentinel value for hrm_index #define G1_NO_HRM_INDEX ((uint) -1) // A dirty card to oop closure for heap regions. It // knows how to get the G1 heap and how to use the bitmap // in the concurrent marker used by G1 to filter remembered // sets. class HeapRegionDCTOC : public DirtyCardToOopClosure { private: HeapRegion* _hr; G1ParPushHeapRSClosure* _rs_scan; G1CollectedHeap* _g1; // Walk the given memory region from bottom to (actual) top // looking for objects and applying the oop closure (_cl) to // them. The base implementation of this treats the area as // blocks, where a block may or may not be an object. Sub- // classes should override this to provide more accurate // or possibly more efficient walking. void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); public: HeapRegionDCTOC(G1CollectedHeap* g1, HeapRegion* hr, G1ParPushHeapRSClosure* cl, CardTableModRefBS::PrecisionStyle precision); }; // The complicating factor is that BlockOffsetTable diverged // significantly, and we need functionality that is only in the G1 version. // So I copied that code, which led to an alternate G1 version of // OffsetTableContigSpace. If the two versions of BlockOffsetTable could // be reconciled, then G1OffsetTableContigSpace could go away. // The idea behind time stamps is the following. We want to keep track of // the highest address where it's safe to scan objects for each region. // This is only relevant for current GC alloc regions so we keep a time stamp // per region to determine if the region has been allocated during the current // GC or not. If the time stamp is current we report a scan_top value which // was saved at the end of the previous GC for retained alloc regions and which is // equal to the bottom for all other regions. // There is a race between card scanners and allocating gc workers where we must ensure // that card scanners do not read the memory allocated by the gc workers. // In order to enforce that, we must not return a value of _top which is more recent than the // time stamp. This is due to the fact that a region may become a gc alloc region at // some point after we've read the timestamp value as being < the current time stamp. // The time stamps are re-initialized to zero at cleanup and at Full GCs. // The current scheme that uses sequential unsigned ints will fail only if we have 4b // evacuation pauses between two cleanups, which is _highly_ unlikely. class G1OffsetTableContigSpace: public CompactibleSpace { friend class VMStructs; HeapWord* _top; HeapWord* volatile _scan_top; protected: G1BlockOffsetArrayContigSpace _offsets; Mutex _par_alloc_lock; volatile unsigned _gc_time_stamp; // When we need to retire an allocation region, while other threads // are also concurrently trying to allocate into it, we typically // allocate a dummy object at the end of the region to ensure that // no more allocations can take place in it. However, sometimes we // want to know where the end of the last "real" object we allocated // into the region was and this is what this keeps track. HeapWord* _pre_dummy_top; public: G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr); void set_top(HeapWord* value) { _top = value; } HeapWord* top() const { return _top; } protected: // Reset the G1OffsetTableContigSpace. virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); HeapWord** top_addr() { return &_top; } // Allocation helpers (return NULL if full). inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value); inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value); public: void reset_after_compaction() { set_top(compaction_top()); } size_t used() const { return byte_size(bottom(), top()); } size_t free() const { return byte_size(top(), end()); } bool is_free_block(const HeapWord* p) const { return p >= top(); } MemRegion used_region() const { return MemRegion(bottom(), top()); } void object_iterate(ObjectClosure* blk); void safe_object_iterate(ObjectClosure* blk); void set_bottom(HeapWord* value); void set_end(HeapWord* value); HeapWord* scan_top() const; void record_timestamp(); void reset_gc_time_stamp() { _gc_time_stamp = 0; } unsigned get_gc_time_stamp() { return _gc_time_stamp; } void record_retained_region(); // See the comment above in the declaration of _pre_dummy_top for an // explanation of what it is. void set_pre_dummy_top(HeapWord* pre_dummy_top) { assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); _pre_dummy_top = pre_dummy_top; } HeapWord* pre_dummy_top() { return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; } void reset_pre_dummy_top() { _pre_dummy_top = NULL; } virtual void clear(bool mangle_space); HeapWord* block_start(const void* p); HeapWord* block_start_const(const void* p) const; void prepare_for_compaction(CompactPoint* cp); // Add offset table update. virtual HeapWord* allocate(size_t word_size); HeapWord* par_allocate(size_t word_size); HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; } // MarkSweep support phase3 virtual HeapWord* initialize_threshold(); virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); virtual void print() const; void reset_bot() { _offsets.reset_bot(); } void print_bot_on(outputStream* out) { _offsets.print_on(out); } }; class HeapRegion: public G1OffsetTableContigSpace { friend class VMStructs; private: // The remembered set for this region. // (Might want to make this "inline" later, to avoid some alloc failure // issues.) HeapRegionRemSet* _rem_set; G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; } void report_region_type_change(G1HeapRegionTraceType::Type to); protected: // The index of this region in the heap region sequence. uint _hrm_index; AllocationContext_t _allocation_context; HeapRegionType _type; // For a humongous region, region in which it starts. HeapRegion* _humongous_start_region; // For the start region of a humongous sequence, it's original end(). HeapWord* _orig_end; // True iff the region is in current collection_set. bool _in_collection_set; // True iff an attempt to evacuate an object in the region failed. bool _evacuation_failed; // A heap region may be a member one of a number of special subsets, each // represented as linked lists through the field below. Currently, there // is only one set: // The collection set. HeapRegion* _next_in_special_set; // next region in the young "generation" region set HeapRegion* _next_young_region; // Next region whose cards need cleaning HeapRegion* _next_dirty_cards_region; // Fields used by the HeapRegionSetBase class and subclasses. HeapRegion* _next; HeapRegion* _prev; #ifdef ASSERT HeapRegionSetBase* _containing_set; #endif // ASSERT // For parallel heapRegion traversal. jint _claimed; // We use concurrent marking to determine the amount of live data // in each heap region. size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. // The calculated GC efficiency of the region. double _gc_efficiency; int _young_index_in_cset; SurvRateGroup* _surv_rate_group; int _age_index; // The start of the unmarked area. The unmarked area extends from this // word until the top and/or end of the region, and is the part // of the region for which no marking was done, i.e. objects may // have been allocated in this part since the last mark phase. // "prev" is the top at the start of the last completed marking. // "next" is the top at the start of the in-progress marking (if any.) HeapWord* _prev_top_at_mark_start; HeapWord* _next_top_at_mark_start; // If a collection pause is in progress, this is the top at the start // of that pause. void init_top_at_mark_start() { assert(_prev_marked_bytes == 0 && _next_marked_bytes == 0, "Must be called after zero_marked_bytes."); HeapWord* bot = bottom(); _prev_top_at_mark_start = bot; _next_top_at_mark_start = bot; } // Cached attributes used in the collection set policy information // The RSet length that was added to the total value // for the collection set. size_t _recorded_rs_length; // The predicted elapsed time that was added to total value // for the collection set. double _predicted_elapsed_time_ms; // The predicted number of bytes to copy that was added to // the total value for the collection set. size_t _predicted_bytes_to_copy; public: HeapRegion(uint hrm_index, G1BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr); // Initializing the HeapRegion not only resets the data structure, but also // resets the BOT for that heap region. // The default values for clear_space means that we will do the clearing if // there's clearing to be done ourselves. We also always mangle the space. virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle); static int LogOfHRGrainBytes; static int LogOfHRGrainWords; static size_t GrainBytes; static size_t GrainWords; static size_t CardsPerRegion; static size_t align_up_to_region_byte_size(size_t sz) { return (sz + (size_t) GrainBytes - 1) & ~((1 << (size_t) LogOfHRGrainBytes) - 1); } static size_t max_region_size(); // It sets up the heap region size (GrainBytes / GrainWords), as // well as other related fields that are based on the heap region // size (LogOfHRGrainBytes / LogOfHRGrainWords / // CardsPerRegion). All those fields are considered constant // throughout the JVM's execution, therefore they should only be set // up once during initialization time. static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size); enum ClaimValues { InitialClaimValue = 0, FinalCountClaimValue = 1, NoteEndClaimValue = 2, ScrubRemSetClaimValue = 3, ParVerifyClaimValue = 4, RebuildRSClaimValue = 5, ParEvacFailureClaimValue = 6, AggregateCountClaimValue = 7, VerifyCountClaimValue = 8, ParMarkRootClaimValue = 9 }; // All allocated blocks are occupied by objects in a HeapRegion bool block_is_obj(const HeapWord* p) const; // Returns the object size for all valid block starts // and the amount of unallocated words if called on top() size_t block_size(const HeapWord* p) const; inline HeapWord* par_allocate_no_bot_updates(size_t word_size); inline HeapWord* allocate_no_bot_updates(size_t word_size); // If this region is a member of a HeapRegionManager, the index in that // sequence, otherwise -1. uint hrm_index() const { return _hrm_index; } // The number of bytes marked live in the region in the last marking phase. size_t marked_bytes() { return _prev_marked_bytes; } size_t live_bytes() { return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); } // The number of bytes counted in the next marking. size_t next_marked_bytes() { return _next_marked_bytes; } // The number of bytes live wrt the next marking. size_t next_live_bytes() { return (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); } // A lower bound on the amount of garbage bytes in the region. size_t garbage_bytes() { size_t used_at_mark_start_bytes = (prev_top_at_mark_start() - bottom()) * HeapWordSize; assert(used_at_mark_start_bytes >= marked_bytes(), "Can't mark more than we have."); return used_at_mark_start_bytes - marked_bytes(); } // Return the amount of bytes we'll reclaim if we collect this // region. This includes not only the known garbage bytes in the // region but also any unallocated space in it, i.e., [top, end), // since it will also be reclaimed if we collect the region. size_t reclaimable_bytes() { size_t known_live_bytes = live_bytes(); assert(known_live_bytes <= capacity(), "sanity"); return capacity() - known_live_bytes; } // An upper bound on the number of live bytes in the region. size_t max_live_bytes() { return used() - garbage_bytes(); } void add_to_marked_bytes(size_t incr_bytes) { _next_marked_bytes = _next_marked_bytes + incr_bytes; assert(_next_marked_bytes <= used(), "invariant" ); } void zero_marked_bytes() { _prev_marked_bytes = _next_marked_bytes = 0; } const char* get_type_str() const { return _type.get_str(); } const char* get_short_type_str() const { return _type.get_short_str(); } G1HeapRegionTraceType::Type get_trace_type() { return _type.get_trace_type(); } bool is_free() const { return _type.is_free(); } bool is_young() const { return _type.is_young(); } bool is_eden() const { return _type.is_eden(); } bool is_survivor() const { return _type.is_survivor(); } bool isHumongous() const { return _type.is_humongous(); } bool startsHumongous() const { return _type.is_starts_humongous(); } bool continuesHumongous() const { return _type.is_continues_humongous(); } bool is_old() const { return _type.is_old(); } // For a humongous region, region in which it starts. HeapRegion* humongous_start_region() const { return _humongous_start_region; } // Return the number of distinct regions that are covered by this region: // 1 if the region is not humongous, >= 1 if the region is humongous. uint region_num() const { if (!isHumongous()) { return 1U; } else { assert(startsHumongous(), "doesn't make sense on HC regions"); assert(capacity() % HeapRegion::GrainBytes == 0, "sanity"); return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes); } } // Return the index + 1 of the last HC regions that's associated // with this HS region. uint last_hc_index() const { assert(startsHumongous(), "don't call this otherwise"); return hrm_index() + region_num(); } // Same as Space::is_in_reserved, but will use the original size of the region. // The original size is different only for start humongous regions. They get // their _end set up to be the end of the last continues region of the // corresponding humongous object. bool is_in_reserved_raw(const void* p) const { return _bottom <= p && p < _orig_end; } // Makes the current region be a "starts humongous" region, i.e., // the first region in a series of one or more contiguous regions // that will contain a single "humongous" object. The two parameters // are as follows: // // new_top : The new value of the top field of this region which // points to the end of the humongous object that's being // allocated. If there is more than one region in the series, top // will lie beyond this region's original end field and on the last // region in the series. // // new_end : The new value of the end field of this region which // points to the end of the last region in the series. If there is // one region in the series (namely: this one) end will be the same // as the original end of this region. // // Updating top and end as described above makes this region look as // if it spans the entire space taken up by all the regions in the // series and an single allocation moved its top to new_top. This // ensures that the space (capacity / allocated) taken up by all // humongous regions can be calculated by just looking at the // "starts humongous" regions and by ignoring the "continues // humongous" regions. void set_startsHumongous(HeapWord* new_top, HeapWord* new_end); // Makes the current region be a "continues humongous' // region. first_hr is the "start humongous" region of the series // which this region will be part of. void set_continuesHumongous(HeapRegion* first_hr); // Unsets the humongous-related fields on the region. void clear_humongous(); // If the region has a remembered set, return a pointer to it. HeapRegionRemSet* rem_set() const { return _rem_set; } // True iff the region is in current collection_set. bool in_collection_set() const { return _in_collection_set; } void set_in_collection_set(bool b) { _in_collection_set = b; } HeapRegion* next_in_collection_set() { assert(in_collection_set(), "should only invoke on member of CS."); assert(_next_in_special_set == NULL || _next_in_special_set->in_collection_set(), "Malformed CS."); return _next_in_special_set; } void set_next_in_collection_set(HeapRegion* r) { assert(in_collection_set(), "should only invoke on member of CS."); assert(r == NULL || r->in_collection_set(), "Malformed CS."); _next_in_special_set = r; } void set_allocation_context(AllocationContext_t context) { _allocation_context = context; } AllocationContext_t allocation_context() const { return _allocation_context; } // Methods used by the HeapRegionSetBase class and subclasses. // Getter and setter for the next and prev fields used to link regions into // linked lists. HeapRegion* next() { return _next; } HeapRegion* prev() { return _prev; } void set_next(HeapRegion* next) { _next = next; } void set_prev(HeapRegion* prev) { _prev = prev; } // Every region added to a set is tagged with a reference to that // set. This is used for doing consistency checking to make sure that // the contents of a set are as they should be and it's only // available in non-product builds. #ifdef ASSERT void set_containing_set(HeapRegionSetBase* containing_set) { assert((containing_set == NULL && _containing_set != NULL) || (containing_set != NULL && _containing_set == NULL), err_msg("containing_set: " PTR_FORMAT " " "_containing_set: " PTR_FORMAT, p2i(containing_set), p2i(_containing_set))); _containing_set = containing_set; } HeapRegionSetBase* containing_set() { return _containing_set; } #else // ASSERT void set_containing_set(HeapRegionSetBase* containing_set) { } // containing_set() is only used in asserts so there's no reason // to provide a dummy version of it. #endif // ASSERT HeapRegion* get_next_young_region() { return _next_young_region; } void set_next_young_region(HeapRegion* hr) { _next_young_region = hr; } HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; } HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; } void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; } bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; } HeapWord* orig_end() const { return _orig_end; } // Reset HR stuff to default values. void hr_clear(bool par, bool clear_space, bool locked = false); void par_clear(); // Get the start of the unmarked area in this region. HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } // Note the start or end of marking. This tells the heap region // that the collector is about to start or has finished (concurrently) // marking the heap. // Notify the region that concurrent marking is starting. Initialize // all fields related to the next marking info. inline void note_start_of_marking(); // Notify the region that concurrent marking has finished. Copy the // (now finalized) next marking info fields into the prev marking // info fields. inline void note_end_of_marking(); // Notify the region that it will be used as to-space during a GC // and we are about to start copying objects into it. inline void note_start_of_copying(bool during_initial_mark); // Notify the region that it ceases being to-space during a GC and // we will not copy objects into it any more. inline void note_end_of_copying(bool during_initial_mark); // Notify the region that we are about to start processing // self-forwarded objects during evac failure handling. void note_self_forwarding_removal_start(bool during_initial_mark, bool during_conc_mark); // Notify the region that we have finished processing self-forwarded // objects during evac failure handling. void note_self_forwarding_removal_end(bool during_initial_mark, bool during_conc_mark, size_t marked_bytes); // Returns "false" iff no object in the region was allocated when the // last mark phase ended. bool is_marked() { return _prev_top_at_mark_start != bottom(); } void reset_during_compaction() { assert(isHumongous() && startsHumongous(), "should only be called for starts humongous regions"); zero_marked_bytes(); init_top_at_mark_start(); } void calc_gc_efficiency(void); double gc_efficiency() { return _gc_efficiency;} int young_index_in_cset() const { return _young_index_in_cset; } void set_young_index_in_cset(int index) { assert( (index == -1) || is_young(), "pre-condition" ); _young_index_in_cset = index; } int age_in_surv_rate_group() { assert( _surv_rate_group != NULL, "pre-condition" ); assert( _age_index > -1, "pre-condition" ); return _surv_rate_group->age_in_group(_age_index); } void record_surv_words_in_group(size_t words_survived) { assert( _surv_rate_group != NULL, "pre-condition" ); assert( _age_index > -1, "pre-condition" ); int age_in_group = age_in_surv_rate_group(); _surv_rate_group->record_surviving_words(age_in_group, words_survived); } int age_in_surv_rate_group_cond() { if (_surv_rate_group != NULL) return age_in_surv_rate_group(); else return -1; } SurvRateGroup* surv_rate_group() { return _surv_rate_group; } void install_surv_rate_group(SurvRateGroup* surv_rate_group) { assert( surv_rate_group != NULL, "pre-condition" ); assert( _surv_rate_group == NULL, "pre-condition" ); assert( is_young(), "pre-condition" ); _surv_rate_group = surv_rate_group; _age_index = surv_rate_group->next_age_index(); } void uninstall_surv_rate_group() { if (_surv_rate_group != NULL) { assert( _age_index > -1, "pre-condition" ); assert( is_young(), "pre-condition" ); _surv_rate_group = NULL; _age_index = -1; } else { assert( _age_index == -1, "pre-condition" ); } } void set_free(); void set_eden(); void set_eden_pre_gc(); void set_survivor(); void set_old(); // Determine if an object has been allocated since the last // mark performed by the collector. This returns true iff the object // is within the unmarked area of the region. bool obj_allocated_since_prev_marking(oop obj) const { return (HeapWord *) obj >= prev_top_at_mark_start(); } bool obj_allocated_since_next_marking(oop obj) const { return (HeapWord *) obj >= next_top_at_mark_start(); } // For parallel heapRegion traversal. bool claimHeapRegion(int claimValue); jint claim_value() { return _claimed; } // Use this carefully: only when you're sure no one is claiming... void set_claim_value(int claimValue) { _claimed = claimValue; } // Returns the "evacuation_failed" property of the region. bool evacuation_failed() { return _evacuation_failed; } // Sets the "evacuation_failed" property of the region. void set_evacuation_failed(bool b) { _evacuation_failed = b; if (b) { _next_marked_bytes = 0; } } // Requires that "mr" be entirely within the region. // Apply "cl->do_object" to all objects that intersect with "mr". // If the iteration encounters an unparseable portion of the region, // or if "cl->abort()" is true after a closure application, // terminate the iteration and return the address of the start of the // subregion that isn't done. (The two can be distinguished by querying // "cl->abort()".) Return of "NULL" indicates that the iteration // completed. HeapWord* object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl); // filter_young: if true and the region is a young region then we // skip the iteration. // card_ptr: if not NULL, and we decide that the card is not young // and we iterate over it, we'll clean the card before we start the // iteration. HeapWord* oops_on_card_seq_iterate_careful(MemRegion mr, FilterOutOfRegionClosure* cl, bool filter_young, jbyte* card_ptr); size_t recorded_rs_length() const { return _recorded_rs_length; } double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; } void set_recorded_rs_length(size_t rs_length) { _recorded_rs_length = rs_length; } void set_predicted_elapsed_time_ms(double ms) { _predicted_elapsed_time_ms = ms; } void set_predicted_bytes_to_copy(size_t bytes) { _predicted_bytes_to_copy = bytes; } virtual CompactibleSpace* next_compaction_space() const; virtual void reset_after_compaction(); // Routines for managing a list of code roots (attached to the // this region's RSet) that point into this heap region. void add_strong_code_root(nmethod* nm); void add_strong_code_root_locked(nmethod* nm); void remove_strong_code_root(nmethod* nm); // Applies blk->do_code_blob() to each of the entries in // the strong code roots list for this region void strong_code_roots_do(CodeBlobClosure* blk) const; // Verify that the entries on the strong code root list for this // region are live and include at least one pointer into this region. void verify_strong_code_roots(VerifyOption vo, bool* failures) const; void print() const; void print_on(outputStream* st) const; // vo == UsePrevMarking -> use "prev" marking information, // vo == UseNextMarking -> use "next" marking information // vo == UseMarkWord -> use the mark word in the object header // // NOTE: Only the "prev" marking information is guaranteed to be // consistent most of the time, so most calls to this should use // vo == UsePrevMarking. // Currently, there is only one case where this is called with // vo == UseNextMarking, which is to verify the "next" marking // information at the end of remark. // Currently there is only one place where this is called with // vo == UseMarkWord, which is to verify the marking during a // full GC. void verify(VerifyOption vo, bool *failures) const; // Override; it uses the "prev" marking information virtual void verify() const; void verify_rem_set(VerifyOption vo, bool *failures) const; void verify_rem_set() const; }; // HeapRegionClosure is used for iterating over regions. // Terminates the iteration when the "doHeapRegion" method returns "true". class HeapRegionClosure : public StackObj { friend class HeapRegionManager; friend class G1CollectedHeap; bool _complete; void incomplete() { _complete = false; } public: HeapRegionClosure(): _complete(true) {} // Typically called on each region until it returns true. virtual bool doHeapRegion(HeapRegion* r) = 0; // True after iteration if the closure was applied to all heap regions // and returned "false" in all cases. bool complete() { return _complete; } }; #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP