ysr@777: /*
xdono@1014:  * Copyright 2001-2009 Sun Microsystems, Inc.  All Rights Reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
ysr@777:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
ysr@777:  * CA 95054 USA or visit www.sun.com if you need additional information or
ysr@777:  * have any questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
ysr@777: // A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
ysr@777: // It uses the "Garbage First" heap organization and algorithm, which
ysr@777: // may combine concurrent marking with parallel, incremental compaction of
ysr@777: // heap subsets that will yield large amounts of garbage.
ysr@777: 
ysr@777: class HeapRegion;
ysr@777: class HeapRegionSeq;
ysr@777: class PermanentGenerationSpec;
ysr@777: class GenerationSpec;
ysr@777: class OopsInHeapRegionClosure;
ysr@777: class G1ScanHeapEvacClosure;
ysr@777: class ObjectClosure;
ysr@777: class SpaceClosure;
ysr@777: class CompactibleSpaceClosure;
ysr@777: class Space;
ysr@777: class G1CollectorPolicy;
ysr@777: class GenRemSet;
ysr@777: class G1RemSet;
ysr@777: class HeapRegionRemSetIterator;
ysr@777: class ConcurrentMark;
ysr@777: class ConcurrentMarkThread;
ysr@777: class ConcurrentG1Refine;
ysr@777: class ConcurrentZFThread;
ysr@777: 
ysr@777: // If want to accumulate detailed statistics on work queues
ysr@777: // turn this on.
ysr@777: #define G1_DETAILED_STATS 0
ysr@777: 
ysr@777: #if G1_DETAILED_STATS
ysr@777: #  define IF_G1_DETAILED_STATS(code) code
ysr@777: #else
ysr@777: #  define IF_G1_DETAILED_STATS(code)
ysr@777: #endif
ysr@777: 
ysr@777: typedef GenericTaskQueue<oop*>    RefToScanQueue;
ysr@777: typedef GenericTaskQueueSet<oop*> RefToScanQueueSet;
ysr@777: 
ysr@777: enum G1GCThreadGroups {
ysr@777:   G1CRGroup = 0,
ysr@777:   G1ZFGroup = 1,
ysr@777:   G1CMGroup = 2,
ysr@777:   G1CLGroup = 3
ysr@777: };
ysr@777: 
ysr@777: enum GCAllocPurpose {
ysr@777:   GCAllocForTenured,
ysr@777:   GCAllocForSurvived,
ysr@777:   GCAllocPurposeCount
ysr@777: };
ysr@777: 
ysr@777: class YoungList : public CHeapObj {
ysr@777: private:
ysr@777:   G1CollectedHeap* _g1h;
ysr@777: 
ysr@777:   HeapRegion* _head;
ysr@777: 
ysr@777:   HeapRegion* _scan_only_head;
ysr@777:   HeapRegion* _scan_only_tail;
ysr@777:   size_t      _length;
ysr@777:   size_t      _scan_only_length;
ysr@777: 
ysr@777:   size_t      _last_sampled_rs_lengths;
ysr@777:   size_t      _sampled_rs_lengths;
ysr@777:   HeapRegion* _curr;
ysr@777:   HeapRegion* _curr_scan_only;
ysr@777: 
ysr@777:   HeapRegion* _survivor_head;
apetrusenko@980:   HeapRegion* _survivor_tail;
ysr@777:   size_t      _survivor_length;
ysr@777: 
ysr@777:   void          empty_list(HeapRegion* list);
ysr@777: 
ysr@777: public:
ysr@777:   YoungList(G1CollectedHeap* g1h);
ysr@777: 
ysr@777:   void          push_region(HeapRegion* hr);
ysr@777:   void          add_survivor_region(HeapRegion* hr);
ysr@777:   HeapRegion*   pop_region();
ysr@777:   void          empty_list();
ysr@777:   bool          is_empty() { return _length == 0; }
ysr@777:   size_t        length() { return _length; }
ysr@777:   size_t        scan_only_length() { return _scan_only_length; }
apetrusenko@980:   size_t        survivor_length() { return _survivor_length; }
ysr@777: 
ysr@777:   void rs_length_sampling_init();
ysr@777:   bool rs_length_sampling_more();
ysr@777:   void rs_length_sampling_next();
ysr@777: 
ysr@777:   void reset_sampled_info() {
ysr@777:     _last_sampled_rs_lengths =   0;
ysr@777:   }
ysr@777:   size_t sampled_rs_lengths() { return _last_sampled_rs_lengths; }
ysr@777: 
ysr@777:   // for development purposes
ysr@777:   void reset_auxilary_lists();
ysr@777:   HeapRegion* first_region() { return _head; }
ysr@777:   HeapRegion* first_scan_only_region() { return _scan_only_head; }
ysr@777:   HeapRegion* first_survivor_region() { return _survivor_head; }
apetrusenko@980:   HeapRegion* last_survivor_region() { return _survivor_tail; }
ysr@777:   HeapRegion* par_get_next_scan_only_region() {
ysr@777:     MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
ysr@777:     HeapRegion* ret = _curr_scan_only;
ysr@777:     if (ret != NULL)
ysr@777:       _curr_scan_only = ret->get_next_young_region();
ysr@777:     return ret;
ysr@777:   }
ysr@777: 
ysr@777:   // debugging
ysr@777:   bool          check_list_well_formed();
ysr@777:   bool          check_list_empty(bool ignore_scan_only_list,
ysr@777:                                  bool check_sample = true);
ysr@777:   void          print();
ysr@777: };
ysr@777: 
ysr@777: class RefineCardTableEntryClosure;
ysr@777: class G1CollectedHeap : public SharedHeap {
ysr@777:   friend class VM_G1CollectForAllocation;
ysr@777:   friend class VM_GenCollectForPermanentAllocation;
ysr@777:   friend class VM_G1CollectFull;
ysr@777:   friend class VM_G1IncCollectionPause;
ysr@777:   friend class VMStructs;
ysr@777: 
ysr@777:   // Closures used in implementation.
ysr@777:   friend class G1ParCopyHelper;
ysr@777:   friend class G1IsAliveClosure;
ysr@777:   friend class G1EvacuateFollowersClosure;
ysr@777:   friend class G1ParScanThreadState;
ysr@777:   friend class G1ParScanClosureSuper;
ysr@777:   friend class G1ParEvacuateFollowersClosure;
ysr@777:   friend class G1ParTask;
ysr@777:   friend class G1FreeGarbageRegionClosure;
ysr@777:   friend class RefineCardTableEntryClosure;
ysr@777:   friend class G1PrepareCompactClosure;
ysr@777:   friend class RegionSorter;
ysr@777:   friend class CountRCClosure;
ysr@777:   friend class EvacPopObjClosure;
ysr@777: 
ysr@777:   // Other related classes.
ysr@777:   friend class G1MarkSweep;
ysr@777: 
ysr@777: private:
ysr@777:   enum SomePrivateConstants {
ysr@777:     VeryLargeInBytes = HeapRegion::GrainBytes/2,
ysr@777:     VeryLargeInWords = VeryLargeInBytes/HeapWordSize,
ysr@777:     MinHeapDeltaBytes = 10 * HeapRegion::GrainBytes,      // FIXME
ysr@777:     NumAPIs = HeapRegion::MaxAge
ysr@777:   };
ysr@777: 
ysr@777:   // The one and only G1CollectedHeap, so static functions can find it.
ysr@777:   static G1CollectedHeap* _g1h;
ysr@777: 
ysr@777:   // Storage for the G1 heap (excludes the permanent generation).
ysr@777:   VirtualSpace _g1_storage;
ysr@777:   MemRegion    _g1_reserved;
ysr@777: 
ysr@777:   // The part of _g1_storage that is currently committed.
ysr@777:   MemRegion _g1_committed;
ysr@777: 
ysr@777:   // The maximum part of _g1_storage that has ever been committed.
ysr@777:   MemRegion _g1_max_committed;
ysr@777: 
ysr@777:   // The number of regions that are completely free.
ysr@777:   size_t _free_regions;
ysr@777: 
ysr@777:   // The number of regions we could create by expansion.
ysr@777:   size_t _expansion_regions;
ysr@777: 
ysr@777:   // Return the number of free regions in the heap (by direct counting.)
ysr@777:   size_t count_free_regions();
ysr@777:   // Return the number of free regions on the free and unclean lists.
ysr@777:   size_t count_free_regions_list();
ysr@777: 
ysr@777:   // The block offset table for the G1 heap.
ysr@777:   G1BlockOffsetSharedArray* _bot_shared;
ysr@777: 
ysr@777:   // Move all of the regions off the free lists, then rebuild those free
ysr@777:   // lists, before and after full GC.
ysr@777:   void tear_down_region_lists();
ysr@777:   void rebuild_region_lists();
ysr@777:   // This sets all non-empty regions to need zero-fill (which they will if
ysr@777:   // they are empty after full collection.)
ysr@777:   void set_used_regions_to_need_zero_fill();
ysr@777: 
ysr@777:   // The sequence of all heap regions in the heap.
ysr@777:   HeapRegionSeq* _hrs;
ysr@777: 
ysr@777:   // The region from which normal-sized objects are currently being
ysr@777:   // allocated.  May be NULL.
ysr@777:   HeapRegion* _cur_alloc_region;
ysr@777: 
ysr@777:   // Postcondition: cur_alloc_region == NULL.
ysr@777:   void abandon_cur_alloc_region();
tonyp@1071:   void abandon_gc_alloc_regions();
ysr@777: 
ysr@777:   // The to-space memory regions into which objects are being copied during
ysr@777:   // a GC.
ysr@777:   HeapRegion* _gc_alloc_regions[GCAllocPurposeCount];
apetrusenko@980:   size_t _gc_alloc_region_counts[GCAllocPurposeCount];
tonyp@1071:   // These are the regions, one per GCAllocPurpose, that are half-full
tonyp@1071:   // at the end of a collection and that we want to reuse during the
tonyp@1071:   // next collection.
tonyp@1071:   HeapRegion* _retained_gc_alloc_regions[GCAllocPurposeCount];
tonyp@1071:   // This specifies whether we will keep the last half-full region at
tonyp@1071:   // the end of a collection so that it can be reused during the next
tonyp@1071:   // collection (this is specified per GCAllocPurpose)
tonyp@1071:   bool _retain_gc_alloc_region[GCAllocPurposeCount];
ysr@777: 
ysr@777:   // A list of the regions that have been set to be alloc regions in the
ysr@777:   // current collection.
ysr@777:   HeapRegion* _gc_alloc_region_list;
ysr@777: 
ysr@777:   // When called by par thread, require par_alloc_during_gc_lock() to be held.
ysr@777:   void push_gc_alloc_region(HeapRegion* hr);
ysr@777: 
ysr@777:   // This should only be called single-threaded.  Undeclares all GC alloc
ysr@777:   // regions.
ysr@777:   void forget_alloc_region_list();
ysr@777: 
ysr@777:   // Should be used to set an alloc region, because there's other
ysr@777:   // associated bookkeeping.
ysr@777:   void set_gc_alloc_region(int purpose, HeapRegion* r);
ysr@777: 
ysr@777:   // Check well-formedness of alloc region list.
ysr@777:   bool check_gc_alloc_regions();
ysr@777: 
ysr@777:   // Outside of GC pauses, the number of bytes used in all regions other
ysr@777:   // than the current allocation region.
ysr@777:   size_t _summary_bytes_used;
ysr@777: 
tonyp@961:   // This is used for a quick test on whether a reference points into
tonyp@961:   // the collection set or not. Basically, we have an array, with one
tonyp@961:   // byte per region, and that byte denotes whether the corresponding
tonyp@961:   // region is in the collection set or not. The entry corresponding
tonyp@961:   // the bottom of the heap, i.e., region 0, is pointed to by
tonyp@961:   // _in_cset_fast_test_base.  The _in_cset_fast_test field has been
tonyp@961:   // biased so that it actually points to address 0 of the address
tonyp@961:   // space, to make the test as fast as possible (we can simply shift
tonyp@961:   // the address to address into it, instead of having to subtract the
tonyp@961:   // bottom of the heap from the address before shifting it; basically
tonyp@961:   // it works in the same way the card table works).
tonyp@961:   bool* _in_cset_fast_test;
tonyp@961: 
tonyp@961:   // The allocated array used for the fast test on whether a reference
tonyp@961:   // points into the collection set or not. This field is also used to
tonyp@961:   // free the array.
tonyp@961:   bool* _in_cset_fast_test_base;
tonyp@961: 
tonyp@961:   // The length of the _in_cset_fast_test_base array.
tonyp@961:   size_t _in_cset_fast_test_length;
tonyp@961: 
iveresov@788:   volatile unsigned _gc_time_stamp;
ysr@777: 
ysr@777:   size_t* _surviving_young_words;
ysr@777: 
ysr@777:   void setup_surviving_young_words();
ysr@777:   void update_surviving_young_words(size_t* surv_young_words);
ysr@777:   void cleanup_surviving_young_words();
ysr@777: 
ysr@777: protected:
ysr@777: 
ysr@777:   // Returns "true" iff none of the gc alloc regions have any allocations
ysr@777:   // since the last call to "save_marks".
ysr@777:   bool all_alloc_regions_no_allocs_since_save_marks();
apetrusenko@980:   // Perform finalization stuff on all allocation regions.
apetrusenko@980:   void retire_all_alloc_regions();
ysr@777: 
ysr@777:   // The number of regions allocated to hold humongous objects.
ysr@777:   int         _num_humongous_regions;
ysr@777:   YoungList*  _young_list;
ysr@777: 
ysr@777:   // The current policy object for the collector.
ysr@777:   G1CollectorPolicy* _g1_policy;
ysr@777: 
ysr@777:   // Parallel allocation lock to protect the current allocation region.
ysr@777:   Mutex  _par_alloc_during_gc_lock;
ysr@777:   Mutex* par_alloc_during_gc_lock() { return &_par_alloc_during_gc_lock; }
ysr@777: 
ysr@777:   // If possible/desirable, allocate a new HeapRegion for normal object
ysr@777:   // allocation sufficient for an allocation of the given "word_size".
ysr@777:   // If "do_expand" is true, will attempt to expand the heap if necessary
ysr@777:   // to to satisfy the request.  If "zero_filled" is true, requires a
ysr@777:   // zero-filled region.
ysr@777:   // (Returning NULL will trigger a GC.)
ysr@777:   virtual HeapRegion* newAllocRegion_work(size_t word_size,
ysr@777:                                           bool do_expand,
ysr@777:                                           bool zero_filled);
ysr@777: 
ysr@777:   virtual HeapRegion* newAllocRegion(size_t word_size,
ysr@777:                                      bool zero_filled = true) {
ysr@777:     return newAllocRegion_work(word_size, false, zero_filled);
ysr@777:   }
ysr@777:   virtual HeapRegion* newAllocRegionWithExpansion(int purpose,
ysr@777:                                                   size_t word_size,
ysr@777:                                                   bool zero_filled = true);
ysr@777: 
ysr@777:   // Attempt to allocate an object of the given (very large) "word_size".
ysr@777:   // Returns "NULL" on failure.
ysr@777:   virtual HeapWord* humongousObjAllocate(size_t word_size);
ysr@777: 
ysr@777:   // If possible, allocate a block of the given word_size, else return "NULL".
ysr@777:   // Returning NULL will trigger GC or heap expansion.
ysr@777:   // These two methods have rather awkward pre- and
ysr@777:   // post-conditions. If they are called outside a safepoint, then
ysr@777:   // they assume that the caller is holding the heap lock. Upon return
ysr@777:   // they release the heap lock, if they are returning a non-NULL
ysr@777:   // value. attempt_allocation_slow() also dirties the cards of a
ysr@777:   // newly-allocated young region after it releases the heap
ysr@777:   // lock. This change in interface was the neatest way to achieve
ysr@777:   // this card dirtying without affecting mem_allocate(), which is a
ysr@777:   // more frequently called method. We tried two or three different
ysr@777:   // approaches, but they were even more hacky.
ysr@777:   HeapWord* attempt_allocation(size_t word_size,
ysr@777:                                bool permit_collection_pause = true);
ysr@777: 
ysr@777:   HeapWord* attempt_allocation_slow(size_t word_size,
ysr@777:                                     bool permit_collection_pause = true);
ysr@777: 
ysr@777:   // Allocate blocks during garbage collection. Will ensure an
ysr@777:   // allocation region, either by picking one or expanding the
ysr@777:   // heap, and then allocate a block of the given size. The block
ysr@777:   // may not be a humongous - it must fit into a single heap region.
ysr@777:   HeapWord* allocate_during_gc(GCAllocPurpose purpose, size_t word_size);
ysr@777:   HeapWord* par_allocate_during_gc(GCAllocPurpose purpose, size_t word_size);
ysr@777: 
ysr@777:   HeapWord* allocate_during_gc_slow(GCAllocPurpose purpose,
ysr@777:                                     HeapRegion*    alloc_region,
ysr@777:                                     bool           par,
ysr@777:                                     size_t         word_size);
ysr@777: 
ysr@777:   // Ensure that no further allocations can happen in "r", bearing in mind
ysr@777:   // that parallel threads might be attempting allocations.
ysr@777:   void par_allocate_remaining_space(HeapRegion* r);
ysr@777: 
apetrusenko@980:   // Retires an allocation region when it is full or at the end of a
apetrusenko@980:   // GC pause.
apetrusenko@980:   void  retire_alloc_region(HeapRegion* alloc_region, bool par);
apetrusenko@980: 
ysr@777:   // Helper function for two callbacks below.
ysr@777:   // "full", if true, indicates that the GC is for a System.gc() request,
ysr@777:   // and should collect the entire heap.  If "clear_all_soft_refs" is true,
ysr@777:   // all soft references are cleared during the GC.  If "full" is false,
ysr@777:   // "word_size" describes the allocation that the GC should
ysr@777:   // attempt (at least) to satisfy.
ysr@777:   void do_collection(bool full, bool clear_all_soft_refs,
ysr@777:                      size_t word_size);
ysr@777: 
ysr@777:   // Callback from VM_G1CollectFull operation.
ysr@777:   // Perform a full collection.
ysr@777:   void do_full_collection(bool clear_all_soft_refs);
ysr@777: 
ysr@777:   // Resize the heap if necessary after a full collection.  If this is
ysr@777:   // after a collect-for allocation, "word_size" is the allocation size,
ysr@777:   // and will be considered part of the used portion of the heap.
ysr@777:   void resize_if_necessary_after_full_collection(size_t word_size);
ysr@777: 
ysr@777:   // Callback from VM_G1CollectForAllocation operation.
ysr@777:   // This function does everything necessary/possible to satisfy a
ysr@777:   // failed allocation request (including collection, expansion, etc.)
ysr@777:   HeapWord* satisfy_failed_allocation(size_t word_size);
ysr@777: 
ysr@777:   // Attempting to expand the heap sufficiently
ysr@777:   // to support an allocation of the given "word_size".  If
ysr@777:   // successful, perform the allocation and return the address of the
ysr@777:   // allocated block, or else "NULL".
ysr@777:   virtual HeapWord* expand_and_allocate(size_t word_size);
ysr@777: 
ysr@777: public:
ysr@777:   // Expand the garbage-first heap by at least the given size (in bytes!).
ysr@777:   // (Rounds up to a HeapRegion boundary.)
ysr@777:   virtual void expand(size_t expand_bytes);
ysr@777: 
ysr@777:   // Do anything common to GC's.
ysr@777:   virtual void gc_prologue(bool full);
ysr@777:   virtual void gc_epilogue(bool full);
ysr@777: 
tonyp@961:   // We register a region with the fast "in collection set" test. We
tonyp@961:   // simply set to true the array slot corresponding to this region.
tonyp@961:   void register_region_with_in_cset_fast_test(HeapRegion* r) {
tonyp@961:     assert(_in_cset_fast_test_base != NULL, "sanity");
tonyp@961:     assert(r->in_collection_set(), "invariant");
tonyp@961:     int index = r->hrs_index();
tonyp@961:     assert(0 <= (size_t) index && (size_t) index < _in_cset_fast_test_length,
tonyp@961:            "invariant");
tonyp@961:     assert(!_in_cset_fast_test_base[index], "invariant");
tonyp@961:     _in_cset_fast_test_base[index] = true;
tonyp@961:   }
tonyp@961: 
tonyp@961:   // This is a fast test on whether a reference points into the
tonyp@961:   // collection set or not. It does not assume that the reference
tonyp@961:   // points into the heap; if it doesn't, it will return false.
tonyp@961:   bool in_cset_fast_test(oop obj) {
tonyp@961:     assert(_in_cset_fast_test != NULL, "sanity");
tonyp@961:     if (_g1_committed.contains((HeapWord*) obj)) {
tonyp@961:       // no need to subtract the bottom of the heap from obj,
tonyp@961:       // _in_cset_fast_test is biased
tonyp@961:       size_t index = ((size_t) obj) >> HeapRegion::LogOfHRGrainBytes;
tonyp@961:       bool ret = _in_cset_fast_test[index];
tonyp@961:       // let's make sure the result is consistent with what the slower
tonyp@961:       // test returns
tonyp@961:       assert( ret || !obj_in_cs(obj), "sanity");
tonyp@961:       assert(!ret ||  obj_in_cs(obj), "sanity");
tonyp@961:       return ret;
tonyp@961:     } else {
tonyp@961:       return false;
tonyp@961:     }
tonyp@961:   }
tonyp@961: 
ysr@777: protected:
ysr@777: 
ysr@777:   // Shrink the garbage-first heap by at most the given size (in bytes!).
ysr@777:   // (Rounds down to a HeapRegion boundary.)
ysr@777:   virtual void shrink(size_t expand_bytes);
ysr@777:   void shrink_helper(size_t expand_bytes);
ysr@777: 
ysr@777:   // Do an incremental collection: identify a collection set, and evacuate
ysr@777:   // its live objects elsewhere.
ysr@777:   virtual void do_collection_pause();
ysr@777: 
ysr@777:   // The guts of the incremental collection pause, executed by the vm
apetrusenko@1112:   // thread.
apetrusenko@1112:   virtual void do_collection_pause_at_safepoint();
ysr@777: 
ysr@777:   // Actually do the work of evacuating the collection set.
ysr@777:   virtual void evacuate_collection_set();
ysr@777: 
ysr@777:   // If this is an appropriate right time, do a collection pause.
ysr@777:   // The "word_size" argument, if non-zero, indicates the size of an
ysr@777:   // allocation request that is prompting this query.
ysr@777:   void do_collection_pause_if_appropriate(size_t word_size);
ysr@777: 
ysr@777:   // The g1 remembered set of the heap.
ysr@777:   G1RemSet* _g1_rem_set;
ysr@777:   // And it's mod ref barrier set, used to track updates for the above.
ysr@777:   ModRefBarrierSet* _mr_bs;
ysr@777: 
iveresov@1051:   // A set of cards that cover the objects for which the Rsets should be updated
iveresov@1051:   // concurrently after the collection.
iveresov@1051:   DirtyCardQueueSet _dirty_card_queue_set;
iveresov@1051: 
ysr@777:   // The Heap Region Rem Set Iterator.
ysr@777:   HeapRegionRemSetIterator** _rem_set_iterator;
ysr@777: 
ysr@777:   // The closure used to refine a single card.
ysr@777:   RefineCardTableEntryClosure* _refine_cte_cl;
ysr@777: 
ysr@777:   // A function to check the consistency of dirty card logs.
ysr@777:   void check_ct_logs_at_safepoint();
ysr@777: 
ysr@777:   // After a collection pause, make the regions in the CS into free
ysr@777:   // regions.
ysr@777:   void free_collection_set(HeapRegion* cs_head);
ysr@777: 
ysr@777:   // Applies "scan_non_heap_roots" to roots outside the heap,
ysr@777:   // "scan_rs" to roots inside the heap (having done "set_region" to
ysr@777:   // indicate the region in which the root resides), and does "scan_perm"
ysr@777:   // (setting the generation to the perm generation.)  If "scan_rs" is
ysr@777:   // NULL, then this step is skipped.  The "worker_i"
ysr@777:   // param is for use with parallel roots processing, and should be
ysr@777:   // the "i" of the calling parallel worker thread's work(i) function.
ysr@777:   // In the sequential case this param will be ignored.
ysr@777:   void g1_process_strong_roots(bool collecting_perm_gen,
ysr@777:                                SharedHeap::ScanningOption so,
ysr@777:                                OopClosure* scan_non_heap_roots,
ysr@777:                                OopsInHeapRegionClosure* scan_rs,
ysr@777:                                OopsInHeapRegionClosure* scan_so,
ysr@777:                                OopsInGenClosure* scan_perm,
ysr@777:                                int worker_i);
ysr@777: 
ysr@777:   void scan_scan_only_set(OopsInHeapRegionClosure* oc,
ysr@777:                           int worker_i);
ysr@777:   void scan_scan_only_region(HeapRegion* hr,
ysr@777:                              OopsInHeapRegionClosure* oc,
ysr@777:                              int worker_i);
ysr@777: 
ysr@777:   // Apply "blk" to all the weak roots of the system.  These include
ysr@777:   // JNI weak roots, the code cache, system dictionary, symbol table,
ysr@777:   // string table, and referents of reachable weak refs.
ysr@777:   void g1_process_weak_roots(OopClosure* root_closure,
ysr@777:                              OopClosure* non_root_closure);
ysr@777: 
ysr@777:   // Invoke "save_marks" on all heap regions.
ysr@777:   void save_marks();
ysr@777: 
ysr@777:   // Free a heap region.
ysr@777:   void free_region(HeapRegion* hr);
ysr@777:   // A component of "free_region", exposed for 'batching'.
ysr@777:   // All the params after "hr" are out params: the used bytes of the freed
ysr@777:   // region(s), the number of H regions cleared, the number of regions
ysr@777:   // freed, and pointers to the head and tail of a list of freed contig
ysr@777:   // regions, linked throught the "next_on_unclean_list" field.
ysr@777:   void free_region_work(HeapRegion* hr,
ysr@777:                         size_t& pre_used,
ysr@777:                         size_t& cleared_h,
ysr@777:                         size_t& freed_regions,
ysr@777:                         UncleanRegionList* list,
ysr@777:                         bool par = false);
ysr@777: 
ysr@777: 
ysr@777:   // The concurrent marker (and the thread it runs in.)
ysr@777:   ConcurrentMark* _cm;
ysr@777:   ConcurrentMarkThread* _cmThread;
ysr@777:   bool _mark_in_progress;
ysr@777: 
ysr@777:   // The concurrent refiner.
ysr@777:   ConcurrentG1Refine* _cg1r;
ysr@777: 
ysr@777:   // The concurrent zero-fill thread.
ysr@777:   ConcurrentZFThread* _czft;
ysr@777: 
ysr@777:   // The parallel task queues
ysr@777:   RefToScanQueueSet *_task_queues;
ysr@777: 
ysr@777:   // True iff a evacuation has failed in the current collection.
ysr@777:   bool _evacuation_failed;
ysr@777: 
ysr@777:   // Set the attribute indicating whether evacuation has failed in the
ysr@777:   // current collection.
ysr@777:   void set_evacuation_failed(bool b) { _evacuation_failed = b; }
ysr@777: 
ysr@777:   // Failed evacuations cause some logical from-space objects to have
ysr@777:   // forwarding pointers to themselves.  Reset them.
ysr@777:   void remove_self_forwarding_pointers();
ysr@777: 
ysr@777:   // When one is non-null, so is the other.  Together, they each pair is
ysr@777:   // an object with a preserved mark, and its mark value.
ysr@777:   GrowableArray<oop>*     _objs_with_preserved_marks;
ysr@777:   GrowableArray<markOop>* _preserved_marks_of_objs;
ysr@777: 
ysr@777:   // Preserve the mark of "obj", if necessary, in preparation for its mark
ysr@777:   // word being overwritten with a self-forwarding-pointer.
ysr@777:   void preserve_mark_if_necessary(oop obj, markOop m);
ysr@777: 
ysr@777:   // The stack of evac-failure objects left to be scanned.
ysr@777:   GrowableArray<oop>*    _evac_failure_scan_stack;
ysr@777:   // The closure to apply to evac-failure objects.
ysr@777: 
ysr@777:   OopsInHeapRegionClosure* _evac_failure_closure;
ysr@777:   // Set the field above.
ysr@777:   void
ysr@777:   set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_closure) {
ysr@777:     _evac_failure_closure = evac_failure_closure;
ysr@777:   }
ysr@777: 
ysr@777:   // Push "obj" on the scan stack.
ysr@777:   void push_on_evac_failure_scan_stack(oop obj);
ysr@777:   // Process scan stack entries until the stack is empty.
ysr@777:   void drain_evac_failure_scan_stack();
ysr@777:   // True iff an invocation of "drain_scan_stack" is in progress; to
ysr@777:   // prevent unnecessary recursion.
ysr@777:   bool _drain_in_progress;
ysr@777: 
ysr@777:   // Do any necessary initialization for evacuation-failure handling.
ysr@777:   // "cl" is the closure that will be used to process evac-failure
ysr@777:   // objects.
ysr@777:   void init_for_evac_failure(OopsInHeapRegionClosure* cl);
ysr@777:   // Do any necessary cleanup for evacuation-failure handling data
ysr@777:   // structures.
ysr@777:   void finalize_for_evac_failure();
ysr@777: 
ysr@777:   // An attempt to evacuate "obj" has failed; take necessary steps.
ysr@777:   void handle_evacuation_failure(oop obj);
ysr@777:   oop handle_evacuation_failure_par(OopsInHeapRegionClosure* cl, oop obj);
ysr@777:   void handle_evacuation_failure_common(oop obj, markOop m);
ysr@777: 
ysr@777: 
ysr@777:   // Ensure that the relevant gc_alloc regions are set.
ysr@777:   void get_gc_alloc_regions();
tonyp@1071:   // We're done with GC alloc regions. We are going to tear down the
tonyp@1071:   // gc alloc list and remove the gc alloc tag from all the regions on
tonyp@1071:   // that list. However, we will also retain the last (i.e., the one
tonyp@1071:   // that is half-full) GC alloc region, per GCAllocPurpose, for
tonyp@1071:   // possible reuse during the next collection, provided
tonyp@1071:   // _retain_gc_alloc_region[] indicates that it should be the
tonyp@1071:   // case. Said regions are kept in the _retained_gc_alloc_regions[]
tonyp@1071:   // array. If the parameter totally is set, we will not retain any
tonyp@1071:   // regions, irrespective of what _retain_gc_alloc_region[]
tonyp@1071:   // indicates.
tonyp@1071:   void release_gc_alloc_regions(bool totally);
tonyp@1071: #ifndef PRODUCT
tonyp@1071:   // Useful for debugging.
tonyp@1071:   void print_gc_alloc_regions();
tonyp@1071: #endif // !PRODUCT
ysr@777: 
ysr@777:   // ("Weak") Reference processing support
ysr@777:   ReferenceProcessor* _ref_processor;
ysr@777: 
ysr@777:   enum G1H_process_strong_roots_tasks {
ysr@777:     G1H_PS_mark_stack_oops_do,
ysr@777:     G1H_PS_refProcessor_oops_do,
ysr@777:     // Leave this one last.
ysr@777:     G1H_PS_NumElements
ysr@777:   };
ysr@777: 
ysr@777:   SubTasksDone* _process_strong_tasks;
ysr@777: 
ysr@777:   // List of regions which require zero filling.
ysr@777:   UncleanRegionList _unclean_region_list;
ysr@777:   bool _unclean_regions_coming;
ysr@777: 
ysr@777: public:
ysr@777:   void set_refine_cte_cl_concurrency(bool concurrent);
ysr@777: 
ysr@777:   RefToScanQueue *task_queue(int i);
ysr@777: 
iveresov@1051:   // A set of cards where updates happened during the GC
iveresov@1051:   DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; }
iveresov@1051: 
ysr@777:   // Create a G1CollectedHeap with the specified policy.
ysr@777:   // Must call the initialize method afterwards.
ysr@777:   // May not return if something goes wrong.
ysr@777:   G1CollectedHeap(G1CollectorPolicy* policy);
ysr@777: 
ysr@777:   // Initialize the G1CollectedHeap to have the initial and
ysr@777:   // maximum sizes, permanent generation, and remembered and barrier sets
ysr@777:   // specified by the policy object.
ysr@777:   jint initialize();
ysr@777: 
ysr@777:   void ref_processing_init();
ysr@777: 
ysr@777:   void set_par_threads(int t) {
ysr@777:     SharedHeap::set_par_threads(t);
ysr@777:     _process_strong_tasks->set_par_threads(t);
ysr@777:   }
ysr@777: 
ysr@777:   virtual CollectedHeap::Name kind() const {
ysr@777:     return CollectedHeap::G1CollectedHeap;
ysr@777:   }
ysr@777: 
ysr@777:   // The current policy object for the collector.
ysr@777:   G1CollectorPolicy* g1_policy() const { return _g1_policy; }
ysr@777: 
ysr@777:   // Adaptive size policy.  No such thing for g1.
ysr@777:   virtual AdaptiveSizePolicy* size_policy() { return NULL; }
ysr@777: 
ysr@777:   // The rem set and barrier set.
ysr@777:   G1RemSet* g1_rem_set() const { return _g1_rem_set; }
ysr@777:   ModRefBarrierSet* mr_bs() const { return _mr_bs; }
ysr@777: 
ysr@777:   // The rem set iterator.
ysr@777:   HeapRegionRemSetIterator* rem_set_iterator(int i) {
ysr@777:     return _rem_set_iterator[i];
ysr@777:   }
ysr@777: 
ysr@777:   HeapRegionRemSetIterator* rem_set_iterator() {
ysr@777:     return _rem_set_iterator[0];
ysr@777:   }
ysr@777: 
ysr@777:   unsigned get_gc_time_stamp() {
ysr@777:     return _gc_time_stamp;
ysr@777:   }
ysr@777: 
ysr@777:   void reset_gc_time_stamp() {
ysr@777:     _gc_time_stamp = 0;
iveresov@788:     OrderAccess::fence();
iveresov@788:   }
iveresov@788: 
iveresov@788:   void increment_gc_time_stamp() {
iveresov@788:     ++_gc_time_stamp;
iveresov@788:     OrderAccess::fence();
ysr@777:   }
ysr@777: 
ysr@777:   void iterate_dirty_card_closure(bool concurrent, int worker_i);
ysr@777: 
ysr@777:   // The shared block offset table array.
ysr@777:   G1BlockOffsetSharedArray* bot_shared() const { return _bot_shared; }
ysr@777: 
ysr@777:   // Reference Processing accessor
ysr@777:   ReferenceProcessor* ref_processor() { return _ref_processor; }
ysr@777: 
ysr@777:   // Reserved (g1 only; super method includes perm), capacity and the used
ysr@777:   // portion in bytes.
ysr@777:   size_t g1_reserved_obj_bytes() { return _g1_reserved.byte_size(); }
ysr@777:   virtual size_t capacity() const;
ysr@777:   virtual size_t used() const;
ysr@777:   size_t recalculate_used() const;
ysr@777: #ifndef PRODUCT
ysr@777:   size_t recalculate_used_regions() const;
ysr@777: #endif // PRODUCT
ysr@777: 
ysr@777:   // These virtual functions do the actual allocation.
ysr@777:   virtual HeapWord* mem_allocate(size_t word_size,
ysr@777:                                  bool   is_noref,
ysr@777:                                  bool   is_tlab,
ysr@777:                                  bool* gc_overhead_limit_was_exceeded);
ysr@777: 
ysr@777:   // Some heaps may offer a contiguous region for shared non-blocking
ysr@777:   // allocation, via inlined code (by exporting the address of the top and
ysr@777:   // end fields defining the extent of the contiguous allocation region.)
ysr@777:   // But G1CollectedHeap doesn't yet support this.
ysr@777: 
ysr@777:   // Return an estimate of the maximum allocation that could be performed
ysr@777:   // without triggering any collection or expansion activity.  In a
ysr@777:   // generational collector, for example, this is probably the largest
ysr@777:   // allocation that could be supported (without expansion) in the youngest
ysr@777:   // generation.  It is "unsafe" because no locks are taken; the result
ysr@777:   // should be treated as an approximation, not a guarantee, for use in
ysr@777:   // heuristic resizing decisions.
ysr@777:   virtual size_t unsafe_max_alloc();
ysr@777: 
ysr@777:   virtual bool is_maximal_no_gc() const {
ysr@777:     return _g1_storage.uncommitted_size() == 0;
ysr@777:   }
ysr@777: 
ysr@777:   // The total number of regions in the heap.
ysr@777:   size_t n_regions();
ysr@777: 
ysr@777:   // The number of regions that are completely free.
ysr@777:   size_t max_regions();
ysr@777: 
ysr@777:   // The number of regions that are completely free.
ysr@777:   size_t free_regions();
ysr@777: 
ysr@777:   // The number of regions that are not completely free.
ysr@777:   size_t used_regions() { return n_regions() - free_regions(); }
ysr@777: 
ysr@777:   // True iff the ZF thread should run.
ysr@777:   bool should_zf();
ysr@777: 
ysr@777:   // The number of regions available for "regular" expansion.
ysr@777:   size_t expansion_regions() { return _expansion_regions; }
ysr@777: 
ysr@777: #ifndef PRODUCT
ysr@777:   bool regions_accounted_for();
ysr@777:   bool print_region_accounting_info();
ysr@777:   void print_region_counts();
ysr@777: #endif
ysr@777: 
ysr@777:   HeapRegion* alloc_region_from_unclean_list(bool zero_filled);
ysr@777:   HeapRegion* alloc_region_from_unclean_list_locked(bool zero_filled);
ysr@777: 
ysr@777:   void put_region_on_unclean_list(HeapRegion* r);
ysr@777:   void put_region_on_unclean_list_locked(HeapRegion* r);
ysr@777: 
ysr@777:   void prepend_region_list_on_unclean_list(UncleanRegionList* list);
ysr@777:   void prepend_region_list_on_unclean_list_locked(UncleanRegionList* list);
ysr@777: 
ysr@777:   void set_unclean_regions_coming(bool b);
ysr@777:   void set_unclean_regions_coming_locked(bool b);
ysr@777:   // Wait for cleanup to be complete.
ysr@777:   void wait_for_cleanup_complete();
ysr@777:   // Like above, but assumes that the calling thread owns the Heap_lock.
ysr@777:   void wait_for_cleanup_complete_locked();
ysr@777: 
ysr@777:   // Return the head of the unclean list.
ysr@777:   HeapRegion* peek_unclean_region_list_locked();
ysr@777:   // Remove and return the head of the unclean list.
ysr@777:   HeapRegion* pop_unclean_region_list_locked();
ysr@777: 
ysr@777:   // List of regions which are zero filled and ready for allocation.
ysr@777:   HeapRegion* _free_region_list;
ysr@777:   // Number of elements on the free list.
ysr@777:   size_t _free_region_list_size;
ysr@777: 
ysr@777:   // If the head of the unclean list is ZeroFilled, move it to the free
ysr@777:   // list.
ysr@777:   bool move_cleaned_region_to_free_list_locked();
ysr@777:   bool move_cleaned_region_to_free_list();
ysr@777: 
ysr@777:   void put_free_region_on_list_locked(HeapRegion* r);
ysr@777:   void put_free_region_on_list(HeapRegion* r);
ysr@777: 
ysr@777:   // Remove and return the head element of the free list.
ysr@777:   HeapRegion* pop_free_region_list_locked();
ysr@777: 
ysr@777:   // If "zero_filled" is true, we first try the free list, then we try the
ysr@777:   // unclean list, zero-filling the result.  If "zero_filled" is false, we
ysr@777:   // first try the unclean list, then the zero-filled list.
ysr@777:   HeapRegion* alloc_free_region_from_lists(bool zero_filled);
ysr@777: 
ysr@777:   // Verify the integrity of the region lists.
ysr@777:   void remove_allocated_regions_from_lists();
ysr@777:   bool verify_region_lists();
ysr@777:   bool verify_region_lists_locked();
ysr@777:   size_t unclean_region_list_length();
ysr@777:   size_t free_region_list_length();
ysr@777: 
ysr@777:   // Perform a collection of the heap; intended for use in implementing
ysr@777:   // "System.gc".  This probably implies as full a collection as the
ysr@777:   // "CollectedHeap" supports.
ysr@777:   virtual void collect(GCCause::Cause cause);
ysr@777: 
ysr@777:   // The same as above but assume that the caller holds the Heap_lock.
ysr@777:   void collect_locked(GCCause::Cause cause);
ysr@777: 
ysr@777:   // This interface assumes that it's being called by the
ysr@777:   // vm thread. It collects the heap assuming that the
ysr@777:   // heap lock is already held and that we are executing in
ysr@777:   // the context of the vm thread.
ysr@777:   virtual void collect_as_vm_thread(GCCause::Cause cause);
ysr@777: 
ysr@777:   // True iff a evacuation has failed in the most-recent collection.
ysr@777:   bool evacuation_failed() { return _evacuation_failed; }
ysr@777: 
ysr@777:   // Free a region if it is totally full of garbage.  Returns the number of
ysr@777:   // bytes freed (0 ==> didn't free it).
ysr@777:   size_t free_region_if_totally_empty(HeapRegion *hr);
ysr@777:   void free_region_if_totally_empty_work(HeapRegion *hr,
ysr@777:                                          size_t& pre_used,
ysr@777:                                          size_t& cleared_h_regions,
ysr@777:                                          size_t& freed_regions,
ysr@777:                                          UncleanRegionList* list,
ysr@777:                                          bool par = false);
ysr@777: 
ysr@777:   // If we've done free region work that yields the given changes, update
ysr@777:   // the relevant global variables.
ysr@777:   void finish_free_region_work(size_t pre_used,
ysr@777:                                size_t cleared_h_regions,
ysr@777:                                size_t freed_regions,
ysr@777:                                UncleanRegionList* list);
ysr@777: 
ysr@777: 
ysr@777:   // Returns "TRUE" iff "p" points into the allocated area of the heap.
ysr@777:   virtual bool is_in(const void* p) const;
ysr@777: 
ysr@777:   // Return "TRUE" iff the given object address is within the collection
ysr@777:   // set.
ysr@777:   inline bool obj_in_cs(oop obj);
ysr@777: 
ysr@777:   // Return "TRUE" iff the given object address is in the reserved
ysr@777:   // region of g1 (excluding the permanent generation).
ysr@777:   bool is_in_g1_reserved(const void* p) const {
ysr@777:     return _g1_reserved.contains(p);
ysr@777:   }
ysr@777: 
ysr@777:   // Returns a MemRegion that corresponds to the space that  has been
ysr@777:   // committed in the heap
ysr@777:   MemRegion g1_committed() {
ysr@777:     return _g1_committed;
ysr@777:   }
ysr@777: 
ysr@777:   NOT_PRODUCT( bool is_in_closed_subset(const void* p) const; )
ysr@777: 
ysr@777:   // Dirty card table entries covering a list of young regions.
ysr@777:   void dirtyCardsForYoungRegions(CardTableModRefBS* ct_bs, HeapRegion* list);
ysr@777: 
ysr@777:   // This resets the card table to all zeros.  It is used after
ysr@777:   // a collection pause which used the card table to claim cards.
ysr@777:   void cleanUpCardTable();
ysr@777: 
ysr@777:   // Iteration functions.
ysr@777: 
ysr@777:   // Iterate over all the ref-containing fields of all objects, calling
ysr@777:   // "cl.do_oop" on each.
ysr@777:   virtual void oop_iterate(OopClosure* cl);
ysr@777: 
ysr@777:   // Same as above, restricted to a memory region.
ysr@777:   virtual void oop_iterate(MemRegion mr, OopClosure* cl);
ysr@777: 
ysr@777:   // Iterate over all objects, calling "cl.do_object" on each.
ysr@777:   virtual void object_iterate(ObjectClosure* cl);
jmasa@952:   virtual void safe_object_iterate(ObjectClosure* cl) { object_iterate(cl); }
ysr@777: 
ysr@777:   // Iterate over all objects allocated since the last collection, calling
ysr@777:   // "cl.do_object" on each.  The heap must have been initialized properly
ysr@777:   // to support this function, or else this call will fail.
ysr@777:   virtual void object_iterate_since_last_GC(ObjectClosure* cl);
ysr@777: 
ysr@777:   // Iterate over all spaces in use in the heap, in ascending address order.
ysr@777:   virtual void space_iterate(SpaceClosure* cl);
ysr@777: 
ysr@777:   // Iterate over heap regions, in address order, terminating the
ysr@777:   // iteration early if the "doHeapRegion" method returns "true".
ysr@777:   void heap_region_iterate(HeapRegionClosure* blk);
ysr@777: 
ysr@777:   // Iterate over heap regions starting with r (or the first region if "r"
ysr@777:   // is NULL), in address order, terminating early if the "doHeapRegion"
ysr@777:   // method returns "true".
ysr@777:   void heap_region_iterate_from(HeapRegion* r, HeapRegionClosure* blk);
ysr@777: 
ysr@777:   // As above but starting from the region at index idx.
ysr@777:   void heap_region_iterate_from(int idx, HeapRegionClosure* blk);
ysr@777: 
ysr@777:   HeapRegion* region_at(size_t idx);
ysr@777: 
ysr@777:   // Divide the heap region sequence into "chunks" of some size (the number
ysr@777:   // of regions divided by the number of parallel threads times some
ysr@777:   // overpartition factor, currently 4).  Assumes that this will be called
ysr@777:   // in parallel by ParallelGCThreads worker threads with discinct worker
ysr@777:   // ids in the range [0..max(ParallelGCThreads-1, 1)], that all parallel
ysr@777:   // calls will use the same "claim_value", and that that claim value is
ysr@777:   // different from the claim_value of any heap region before the start of
ysr@777:   // the iteration.  Applies "blk->doHeapRegion" to each of the regions, by
ysr@777:   // attempting to claim the first region in each chunk, and, if
ysr@777:   // successful, applying the closure to each region in the chunk (and
ysr@777:   // setting the claim value of the second and subsequent regions of the
ysr@777:   // chunk.)  For now requires that "doHeapRegion" always returns "false",
ysr@777:   // i.e., that a closure never attempt to abort a traversal.
ysr@777:   void heap_region_par_iterate_chunked(HeapRegionClosure* blk,
ysr@777:                                        int worker,
ysr@777:                                        jint claim_value);
ysr@777: 
tonyp@825:   // It resets all the region claim values to the default.
tonyp@825:   void reset_heap_region_claim_values();
tonyp@825: 
tonyp@790: #ifdef ASSERT
tonyp@790:   bool check_heap_region_claim_values(jint claim_value);
tonyp@790: #endif // ASSERT
tonyp@790: 
ysr@777:   // Iterate over the regions (if any) in the current collection set.
ysr@777:   void collection_set_iterate(HeapRegionClosure* blk);
ysr@777: 
ysr@777:   // As above but starting from region r
ysr@777:   void collection_set_iterate_from(HeapRegion* r, HeapRegionClosure *blk);
ysr@777: 
ysr@777:   // Returns the first (lowest address) compactible space in the heap.
ysr@777:   virtual CompactibleSpace* first_compactible_space();
ysr@777: 
ysr@777:   // A CollectedHeap will contain some number of spaces.  This finds the
ysr@777:   // space containing a given address, or else returns NULL.
ysr@777:   virtual Space* space_containing(const void* addr) const;
ysr@777: 
ysr@777:   // A G1CollectedHeap will contain some number of heap regions.  This
ysr@777:   // finds the region containing a given address, or else returns NULL.
ysr@777:   HeapRegion* heap_region_containing(const void* addr) const;
ysr@777: 
ysr@777:   // Like the above, but requires "addr" to be in the heap (to avoid a
ysr@777:   // null-check), and unlike the above, may return an continuing humongous
ysr@777:   // region.
ysr@777:   HeapRegion* heap_region_containing_raw(const void* addr) const;
ysr@777: 
ysr@777:   // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
ysr@777:   // each address in the (reserved) heap is a member of exactly
ysr@777:   // one block.  The defining characteristic of a block is that it is
ysr@777:   // possible to find its size, and thus to progress forward to the next
ysr@777:   // block.  (Blocks may be of different sizes.)  Thus, blocks may
ysr@777:   // represent Java objects, or they might be free blocks in a
ysr@777:   // free-list-based heap (or subheap), as long as the two kinds are
ysr@777:   // distinguishable and the size of each is determinable.
ysr@777: 
ysr@777:   // Returns the address of the start of the "block" that contains the
ysr@777:   // address "addr".  We say "blocks" instead of "object" since some heaps
ysr@777:   // may not pack objects densely; a chunk may either be an object or a
ysr@777:   // non-object.
ysr@777:   virtual HeapWord* block_start(const void* addr) const;
ysr@777: 
ysr@777:   // Requires "addr" to be the start of a chunk, and returns its size.
ysr@777:   // "addr + size" is required to be the start of a new chunk, or the end
ysr@777:   // of the active area of the heap.
ysr@777:   virtual size_t block_size(const HeapWord* addr) const;
ysr@777: 
ysr@777:   // Requires "addr" to be the start of a block, and returns "TRUE" iff
ysr@777:   // the block is an object.
ysr@777:   virtual bool block_is_obj(const HeapWord* addr) const;
ysr@777: 
ysr@777:   // Does this heap support heap inspection? (+PrintClassHistogram)
ysr@777:   virtual bool supports_heap_inspection() const { return true; }
ysr@777: 
ysr@777:   // Section on thread-local allocation buffers (TLABs)
ysr@777:   // See CollectedHeap for semantics.
ysr@777: 
ysr@777:   virtual bool supports_tlab_allocation() const;
ysr@777:   virtual size_t tlab_capacity(Thread* thr) const;
ysr@777:   virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
ysr@777:   virtual HeapWord* allocate_new_tlab(size_t size);
ysr@777: 
ysr@777:   // Can a compiler initialize a new object without store barriers?
ysr@777:   // This permission only extends from the creation of a new object
ysr@777:   // via a TLAB up to the first subsequent safepoint.
ysr@777:   virtual bool can_elide_tlab_store_barriers() const {
ysr@777:     // Since G1's TLAB's may, on occasion, come from non-young regions
ysr@777:     // as well. (Is there a flag controlling that? XXX)
ysr@777:     return false;
ysr@777:   }
ysr@777: 
ysr@777:   // Can a compiler elide a store barrier when it writes
ysr@777:   // a permanent oop into the heap?  Applies when the compiler
ysr@777:   // is storing x to the heap, where x->is_perm() is true.
ysr@777:   virtual bool can_elide_permanent_oop_store_barriers() const {
ysr@777:     // At least until perm gen collection is also G1-ified, at
ysr@777:     // which point this should return false.
ysr@777:     return true;
ysr@777:   }
ysr@777: 
ysr@777:   virtual bool allocs_are_zero_filled();
ysr@777: 
ysr@777:   // The boundary between a "large" and "small" array of primitives, in
ysr@777:   // words.
ysr@777:   virtual size_t large_typearray_limit();
ysr@777: 
ysr@777:   // Returns "true" iff the given word_size is "very large".
ysr@777:   static bool isHumongous(size_t word_size) {
ysr@777:     return word_size >= VeryLargeInWords;
ysr@777:   }
ysr@777: 
ysr@777:   // Update mod union table with the set of dirty cards.
ysr@777:   void updateModUnion();
ysr@777: 
ysr@777:   // Set the mod union bits corresponding to the given memRegion.  Note
ysr@777:   // that this is always a safe operation, since it doesn't clear any
ysr@777:   // bits.
ysr@777:   void markModUnionRange(MemRegion mr);
ysr@777: 
ysr@777:   // Records the fact that a marking phase is no longer in progress.
ysr@777:   void set_marking_complete() {
ysr@777:     _mark_in_progress = false;
ysr@777:   }
ysr@777:   void set_marking_started() {
ysr@777:     _mark_in_progress = true;
ysr@777:   }
ysr@777:   bool mark_in_progress() {
ysr@777:     return _mark_in_progress;
ysr@777:   }
ysr@777: 
ysr@777:   // Print the maximum heap capacity.
ysr@777:   virtual size_t max_capacity() const;
ysr@777: 
ysr@777:   virtual jlong millis_since_last_gc();
ysr@777: 
ysr@777:   // Perform any cleanup actions necessary before allowing a verification.
ysr@777:   virtual void prepare_for_verify();
ysr@777: 
ysr@777:   // Perform verification.
ysr@777:   virtual void verify(bool allow_dirty, bool silent);
ysr@777:   virtual void print() const;
ysr@777:   virtual void print_on(outputStream* st) const;
ysr@777: 
ysr@777:   virtual void print_gc_threads_on(outputStream* st) const;
ysr@777:   virtual void gc_threads_do(ThreadClosure* tc) const;
ysr@777: 
ysr@777:   // Override
ysr@777:   void print_tracing_info() const;
ysr@777: 
ysr@777:   // If "addr" is a pointer into the (reserved?) heap, returns a positive
ysr@777:   // number indicating the "arena" within the heap in which "addr" falls.
ysr@777:   // Or else returns 0.
ysr@777:   virtual int addr_to_arena_id(void* addr) const;
ysr@777: 
ysr@777:   // Convenience function to be used in situations where the heap type can be
ysr@777:   // asserted to be this type.
ysr@777:   static G1CollectedHeap* heap();
ysr@777: 
ysr@777:   void empty_young_list();
ysr@777:   bool should_set_young_locked();
ysr@777: 
ysr@777:   void set_region_short_lived_locked(HeapRegion* hr);
ysr@777:   // add appropriate methods for any other surv rate groups
ysr@777: 
ysr@777:   void young_list_rs_length_sampling_init() {
ysr@777:     _young_list->rs_length_sampling_init();
ysr@777:   }
ysr@777:   bool young_list_rs_length_sampling_more() {
ysr@777:     return _young_list->rs_length_sampling_more();
ysr@777:   }
ysr@777:   void young_list_rs_length_sampling_next() {
ysr@777:     _young_list->rs_length_sampling_next();
ysr@777:   }
ysr@777:   size_t young_list_sampled_rs_lengths() {
ysr@777:     return _young_list->sampled_rs_lengths();
ysr@777:   }
ysr@777: 
ysr@777:   size_t young_list_length()   { return _young_list->length(); }
ysr@777:   size_t young_list_scan_only_length() {
ysr@777:                                       return _young_list->scan_only_length(); }
ysr@777: 
ysr@777:   HeapRegion* pop_region_from_young_list() {
ysr@777:     return _young_list->pop_region();
ysr@777:   }
ysr@777: 
ysr@777:   HeapRegion* young_list_first_region() {
ysr@777:     return _young_list->first_region();
ysr@777:   }
ysr@777: 
ysr@777:   // debugging
ysr@777:   bool check_young_list_well_formed() {
ysr@777:     return _young_list->check_list_well_formed();
ysr@777:   }
ysr@777:   bool check_young_list_empty(bool ignore_scan_only_list,
ysr@777:                               bool check_sample = true);
ysr@777: 
ysr@777:   // *** Stuff related to concurrent marking.  It's not clear to me that so
ysr@777:   // many of these need to be public.
ysr@777: 
ysr@777:   // The functions below are helper functions that a subclass of
ysr@777:   // "CollectedHeap" can use in the implementation of its virtual
ysr@777:   // functions.
ysr@777:   // This performs a concurrent marking of the live objects in a
ysr@777:   // bitmap off to the side.
ysr@777:   void doConcurrentMark();
ysr@777: 
ysr@777:   // This is called from the marksweep collector which then does
ysr@777:   // a concurrent mark and verifies that the results agree with
ysr@777:   // the stop the world marking.
ysr@777:   void checkConcurrentMark();
ysr@777:   void do_sync_mark();
ysr@777: 
ysr@777:   bool isMarkedPrev(oop obj) const;
ysr@777:   bool isMarkedNext(oop obj) const;
ysr@777: 
ysr@777:   // Determine if an object is dead, given the object and also
ysr@777:   // the region to which the object belongs. An object is dead
ysr@777:   // iff a) it was not allocated since the last mark and b) it
ysr@777:   // is not marked.
ysr@777: 
ysr@777:   bool is_obj_dead(const oop obj, const HeapRegion* hr) const {
ysr@777:     return
ysr@777:       !hr->obj_allocated_since_prev_marking(obj) &&
ysr@777:       !isMarkedPrev(obj);
ysr@777:   }
ysr@777: 
ysr@777:   // This is used when copying an object to survivor space.
ysr@777:   // If the object is marked live, then we mark the copy live.
ysr@777:   // If the object is allocated since the start of this mark
ysr@777:   // cycle, then we mark the copy live.
ysr@777:   // If the object has been around since the previous mark
ysr@777:   // phase, and hasn't been marked yet during this phase,
ysr@777:   // then we don't mark it, we just wait for the
ysr@777:   // current marking cycle to get to it.
ysr@777: 
ysr@777:   // This function returns true when an object has been
ysr@777:   // around since the previous marking and hasn't yet
ysr@777:   // been marked during this marking.
ysr@777: 
ysr@777:   bool is_obj_ill(const oop obj, const HeapRegion* hr) const {
ysr@777:     return
ysr@777:       !hr->obj_allocated_since_next_marking(obj) &&
ysr@777:       !isMarkedNext(obj);
ysr@777:   }
ysr@777: 
ysr@777:   // Determine if an object is dead, given only the object itself.
ysr@777:   // This will find the region to which the object belongs and
ysr@777:   // then call the region version of the same function.
ysr@777: 
ysr@777:   // Added if it is in permanent gen it isn't dead.
ysr@777:   // Added if it is NULL it isn't dead.
ysr@777: 
ysr@777:   bool is_obj_dead(oop obj) {
ysr@777:     HeapRegion* hr = heap_region_containing(obj);
ysr@777:     if (hr == NULL) {
ysr@777:       if (Universe::heap()->is_in_permanent(obj))
ysr@777:         return false;
ysr@777:       else if (obj == NULL) return false;
ysr@777:       else return true;
ysr@777:     }
ysr@777:     else return is_obj_dead(obj, hr);
ysr@777:   }
ysr@777: 
ysr@777:   bool is_obj_ill(oop obj) {
ysr@777:     HeapRegion* hr = heap_region_containing(obj);
ysr@777:     if (hr == NULL) {
ysr@777:       if (Universe::heap()->is_in_permanent(obj))
ysr@777:         return false;
ysr@777:       else if (obj == NULL) return false;
ysr@777:       else return true;
ysr@777:     }
ysr@777:     else return is_obj_ill(obj, hr);
ysr@777:   }
ysr@777: 
ysr@777:   // The following is just to alert the verification code
ysr@777:   // that a full collection has occurred and that the
ysr@777:   // remembered sets are no longer up to date.
ysr@777:   bool _full_collection;
ysr@777:   void set_full_collection() { _full_collection = true;}
ysr@777:   void clear_full_collection() {_full_collection = false;}
ysr@777:   bool full_collection() {return _full_collection;}
ysr@777: 
ysr@777:   ConcurrentMark* concurrent_mark() const { return _cm; }
ysr@777:   ConcurrentG1Refine* concurrent_g1_refine() const { return _cg1r; }
ysr@777: 
ysr@777: public:
ysr@777:   void stop_conc_gc_threads();
ysr@777: 
ysr@777:   // <NEW PREDICTION>
ysr@777: 
ysr@777:   double predict_region_elapsed_time_ms(HeapRegion* hr, bool young);
ysr@777:   void check_if_region_is_too_expensive(double predicted_time_ms);
ysr@777:   size_t pending_card_num();
ysr@777:   size_t max_pending_card_num();
ysr@777:   size_t cards_scanned();
ysr@777: 
ysr@777:   // </NEW PREDICTION>
ysr@777: 
ysr@777: protected:
ysr@777:   size_t _max_heap_capacity;
ysr@777: 
ysr@777: //  debug_only(static void check_for_valid_allocation_state();)
ysr@777: 
ysr@777: public:
ysr@777:   // Temporary: call to mark things unimplemented for the G1 heap (e.g.,
ysr@777:   // MemoryService).  In productization, we can make this assert false
ysr@777:   // to catch such places (as well as searching for calls to this...)
ysr@777:   static void g1_unimplemented();
ysr@777: 
ysr@777: };
ysr@777: 
ysr@777: // Local Variables: ***
ysr@777: // c-indentation-style: gnu ***
ysr@777: // End: ***