Java example source code file (heapRegion.hpp)
The heapRegion.hpp Java example source code
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#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);
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
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