jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/heapRegion.hpp@96b1c2e06e25 (annotated)

src/share/vm/gc_implementation/g1/heapRegion.hpp@96b1c2e06e25 (annotated)

src/share/vm/gc_implementation/g1/heapRegion.hpp

Mon, 24 Mar 2014 15:30:36 +0100

author: tschatzl
date: Mon, 24 Mar 2014 15:30:36 +0100
changeset 6404: 96b1c2e06e25
parent 5701: 40136aa2cdb1
child 6422: 8ee855b4e667
permissions: -rw-r--r--

8027295: Free CSet takes ~50% of young pause time
Summary: Improve fast card cache iteration and avoid taking locks when freeing the collection set.
Reviewed-by: brutisso

 /*
  * Copyright (c) 2001, 2013, 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/g1BlockOffsetTable.inline.hpp"
 #include "gc_implementation/g1/g1_specialized_oop_closures.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"
 #if INCLUDE_ALL_GCS
 // 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 CompactibleSpace;
 class ContiguousSpace;
 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_)->hrs_index(), \
                 (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : \
                 (_hr_)->startsHumongous() ? "HS" : \
                 (_hr_)->continuesHumongous() ? "HC" : \
                 !(_hr_)->is_empty() ? "O" : "F", \
                 (_hr_)->bottom(), (_hr_)->top(), (_hr_)->end()
 // sentinel value for hrs_index
 #define G1_NULL_HRS_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 ContiguousSpaceDCTOC {
 public:
   // Specification of possible DirtyCardToOopClosure filtering.
   enum FilterKind {
     NoFilterKind,
     IntoCSFilterKind,
     OutOfRegionFilterKind
   };
 protected:
   HeapRegion* _hr;
   FilterKind _fk;
   G1CollectedHeap* _g1;
   void walk_mem_region_with_cl(MemRegion mr,
                                HeapWord* bottom, HeapWord* top,
                                ExtendedOopClosure* cl);
   // We don't specialize this for FilteringClosure; filtering is handled by
   // the "FilterKind" mechanism.  But we provide this to avoid a compiler
   // warning.
   void walk_mem_region_with_cl(MemRegion mr,
                                HeapWord* bottom, HeapWord* top,
                                FilteringClosure* cl) {
     HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top,
                                              (ExtendedOopClosure*)cl);
   }
   // Get the actual top of the area on which the closure will
   // operate, given where the top is assumed to be (the end of the
   // memory region passed to do_MemRegion) and where the object
   // at the top is assumed to start. For example, an object may
   // start at the top but actually extend past the assumed top,
   // in which case the top becomes the end of the object.
   HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) {
     return ContiguousSpaceDCTOC::get_actual_top(top, top_obj);
   }
   // 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) {
     Filtering_DCTOC::walk_mem_region(mr, bottom, top);
   }
 public:
   HeapRegionDCTOC(G1CollectedHeap* g1,
                   HeapRegion* hr, ExtendedOopClosure* cl,
                   CardTableModRefBS::PrecisionStyle precision,
                   FilterKind fk);
 };
 // 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. Doing a save_marks on
 // all regions at every GC pause is time consuming (if I remember
 // well, 10ms or so). So, we would like to do that only for regions
 // that are GC alloc regions. To achieve this, we use time
 // stamps. For every evacuation pause, G1CollectedHeap generates a
 // unique time stamp (essentially a counter that gets
 // incremented). Every time we want to call save_marks on a region,
 // we set the saved_mark_word to top and also copy the current GC
 // time stamp to the time stamp field of the space. Reading the
 // saved_mark_word involves checking the time stamp of the
 // region. If it is the same as the current GC time stamp, then we
 // can safely read the saved_mark_word field, as it is valid. If the
 // time stamp of the region is not the same as the current GC time
 // stamp, then we instead read top, as the saved_mark_word field is
 // invalid. Time stamps (on the regions and also on the
 // G1CollectedHeap) are reset at every cleanup (we iterate over
 // the regions anyway) and at the end of a Full GC. 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 ContiguousSpace {
   friend class VMStructs;
  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_bottom(HeapWord* value);
   void set_end(HeapWord* value);
   virtual HeapWord* saved_mark_word() const;
   virtual void set_saved_mark();
   void reset_gc_time_stamp() { _gc_time_stamp = 0; }
   unsigned get_gc_time_stamp() { return _gc_time_stamp; }
   // 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;
   // Add offset table update.
   virtual HeapWord* allocate(size_t word_size);
   HeapWord* par_allocate(size_t word_size);
   // MarkSweep support phase3
   virtual HeapWord* initialize_threshold();
   virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
   virtual void print() const;
   void reset_bot() {
     _offsets.zero_bottom_entry();
     _offsets.initialize_threshold();
   }
   void update_bot_for_object(HeapWord* start, size_t word_size) {
     _offsets.alloc_block(start, word_size);
   }
   void print_bot_on(outputStream* out) {
     _offsets.print_on(out);
   }
 };
 class HeapRegion: public G1OffsetTableContigSpace {
   friend class VMStructs;
  private:
   enum HumongousType {
     NotHumongous = 0,
     StartsHumongous,
     ContinuesHumongous
   };
   // Requires that the region "mr" be dense with objects, and begin and end
   // with an object.
   void oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl);
   // 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; }
  protected:
   // The index of this region in the heap region sequence.
   uint  _hrs_index;
   HumongousType _humongous_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, these
   // sets include:
   //   The collection set.
   //   The set of allocation regions used in a collection pause.
   //   Spaces that may contain gray objects.
   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;
 #ifdef ASSERT
   HeapRegionSetBase* _containing_set;
 #endif // ASSERT
   bool _pending_removal;
   // 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;
   enum YoungType {
     NotYoung,                   // a region is not young
     Young,                      // a region is young
     Survivor                    // a region is young and it contains survivors
   };
   volatile YoungType _young_type;
   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;
   }
   void set_young_type(YoungType new_type) {
     //assert(_young_type != new_type, "setting the same type" );
     // TODO: add more assertions here
     _young_type = new_type;
   }
   // 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 hrs_index,
              G1BlockOffsetSharedArray* sharedOffsetArray,
              MemRegion mr);
   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
   };
   inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
     assert(is_young(), "we can only skip BOT updates on young regions");
     return ContiguousSpace::par_allocate(word_size);
   }
   inline HeapWord* allocate_no_bot_updates(size_t word_size) {
     assert(is_young(), "we can only skip BOT updates on young regions");
     return ContiguousSpace::allocate(word_size);
   }
   // If this region is a member of a HeapRegionSeq, the index in that
   // sequence, otherwise -1.
   uint hrs_index() const { return _hrs_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;
   }
   bool isHumongous() const { return _humongous_type != NotHumongous; }
   bool startsHumongous() const { return _humongous_type == StartsHumongous; }
   bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
   // 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 hrs_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 set_notHumongous();
   // 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;
   }
   // Methods used by the HeapRegionSetBase class and subclasses.
   // Getter and setter for the next field used to link regions into
   // linked lists.
   HeapRegion* next()              { return _next; }
   void set_next(HeapRegion* next) { _next = next; }
   // 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,
                    containing_set, _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
   // If we want to remove regions from a list in bulk we can simply tag
   // them with the pending_removal tag and call the
   // remove_all_pending() method on the list.
   bool pending_removal() { return _pending_removal; }
   void set_pending_removal(bool pending_removal) {
     if (pending_removal) {
       assert(!_pending_removal && containing_set() != NULL,
              "can only set pending removal to true if it's false and "
              "the region belongs to a region set");
     } else {
       assert( _pending_removal && containing_set() == NULL,
               "can only set pending removal to false if it's true and "
               "the region does not belong to a region set");
     }
     _pending_removal = pending_removal;
   }
   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() { return _orig_end; }
   // Allows logical separation between objects allocated before and after.
   void save_marks();
   // 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; }
   // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
   // allocated in the current region before the last call to "save_mark".
   void oop_before_save_marks_iterate(ExtendedOopClosure* cl);
   // 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;}
   bool is_young() const     { return _young_type != NotYoung; }
   bool is_survivor() const  { return _young_type == Survivor; }
   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_young() { set_young_type(Young); }
   void set_survivor() { set_young_type(Survivor); }
   void set_not_young() { set_young_type(NotYoung); }
   // 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);
   // A version of block start that is guaranteed to find *some* block
   // boundary at or before "p", but does not object iteration, and may
   // therefore be used safely when the heap is unparseable.
   HeapWord* block_start_careful(const void* p) const {
     return _offsets.block_start_careful(p);
   }
   // Requires that "addr" is within the region.  Returns the start of the
   // first ("careful") block that starts at or after "addr", or else the
   // "end" of the region if there is no such block.
   HeapWord* next_block_start_careful(HeapWord* addr);
   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;
   }
 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix)  \
   virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
   SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
   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 remove_strong_code_root(nmethod* nm);
   // During a collection, migrate the successfully evacuated
   // strong code roots that referenced into this region to the
   // new regions that they now point into. Unsuccessfully
   // evacuated code roots are not migrated.
   void migrate_strong_code_roots();
   // 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;
 };
 // HeapRegionClosure is used for iterating over regions.
 // Terminates the iteration when the "doHeapRegion" method returns "true".
 class HeapRegionClosure : public StackObj {
   friend class HeapRegionSeq;
   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 // INCLUDE_ALL_GCS
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/heapRegion.hpp@96b1c2e06e25 (annotated)

src/share/vm/gc_implementation/g1/heapRegion.hpp