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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP

 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP

 #include "gc_implementation/g1/heapRegion.hpp"

 // Large buffer for some cases where the output might be larger than normal.

 #define HRS_ERR_MSG_BUFSZ 512

 typedef FormatBuffer<HRS_ERR_MSG_BUFSZ> hrs_err_msg;

 // Set verification will be forced either if someone defines

 // HEAP_REGION_SET_FORCE_VERIFY to be 1, or in builds in which

 // asserts are compiled in.

 #ifndef HEAP_REGION_SET_FORCE_VERIFY

 #define HEAP_REGION_SET_FORCE_VERIFY defined(ASSERT)

 #endif // HEAP_REGION_SET_FORCE_VERIFY

 //////////////////// HeapRegionSetBase ////////////////////

 // Base class for all the classes that represent heap region sets. It

 // contains the basic attributes that each set needs to maintain

 // (e.g., length, region num, used bytes sum) plus any shared

 // functionality (e.g., verification).

 class hrs_ext_msg;

 typedef enum {

   HRSPhaseNone,

   HRSPhaseEvacuation,

   HRSPhaseCleanup,

   HRSPhaseFullGC

 } HRSPhase;

 class HRSPhaseSetter;

 class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC {

   friend class hrs_ext_msg;

   friend class HRSPhaseSetter;

   friend class VMStructs;

 protected:

   static uint _unrealistically_long_length;

   // The number of regions added to the set. If the set contains

   // only humongous regions, this reflects only 'starts humongous'

   // regions and does not include 'continues humongous' ones.

   uint _length;

   // The total number of regions represented by the set. If the set

   // does not contain humongous regions, this should be the same as

   // _length. If the set contains only humongous regions, this will

   // include the 'continues humongous' regions.

   uint _region_num;

   // We don't keep track of the total capacity explicitly, we instead

   // recalculate it based on _region_num and the heap region size.

   // The sum of used bytes in the all the regions in the set.

   size_t _total_used_bytes;

   const char* _name;

   bool        _verify_in_progress;

   uint        _calc_length;

   uint        _calc_region_num;

   size_t      _calc_total_capacity_bytes;

   size_t      _calc_total_used_bytes;

   // This is here so that it can be used in the subclasses to assert

   // something different depending on which phase the GC is in. This

   // can be particularly helpful in the check_mt_safety() methods.

   static HRSPhase _phase;

   // Only used by HRSPhaseSetter.

   static void clear_phase();

   static void set_phase(HRSPhase phase);

   // verify_region() is used to ensure that the contents of a region

   // added to / removed from a set are consistent. Different sets

   // make different assumptions about the regions added to them. So

   // each set can override verify_region_extra(), which is called

   // from verify_region(), and do any extra verification it needs to

   // perform in that.

   virtual const char* verify_region_extra(HeapRegion* hr) { return NULL; }

   bool verify_region(HeapRegion* hr,

                      HeapRegionSetBase* expected_containing_set);

   // Indicates whether all regions in the set should be humongous or

   // not. Only used during verification.

   virtual bool regions_humongous() = 0;

   // Indicates whether all regions in the set should be empty or

   // not. Only used during verification.

   virtual bool regions_empty() = 0;

   // Subclasses can optionally override this to do MT safety protocol

   // checks. It is called in an assert from all methods that perform

   // updates on the set (and subclasses should also call it too).

   virtual bool check_mt_safety() { return true; }

   // fill_in_ext_msg() writes the the values of the set's attributes

   // in the custom err_msg (hrs_ext_msg). fill_in_ext_msg_extra()

   // allows subclasses to append further information.

   virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg) { }

   void fill_in_ext_msg(hrs_ext_msg* msg, const char* message);

   // It updates the fields of the set to reflect hr being added to

   // the set.

   inline void update_for_addition(HeapRegion* hr);

   // It updates the fields of the set to reflect hr being added to

   // the set and tags the region appropriately.

   inline void add_internal(HeapRegion* hr);

   // It updates the fields of the set to reflect hr being removed

   // from the set.

   inline void update_for_removal(HeapRegion* hr);

   // It updates the fields of the set to reflect hr being removed

   // from the set and tags the region appropriately.

   inline void remove_internal(HeapRegion* hr);

   // It clears all the fields of the sets. Note: it will not iterate

   // over the set and remove regions from it. It assumes that the

   // caller has already done so. It will literally just clear the fields.

   virtual void clear();

   HeapRegionSetBase(const char* name);

 public:

   static void set_unrealistically_long_length(uint len);

   const char* name() { return _name; }

   uint length() { return _length; }

   bool is_empty() { return _length == 0; }

   uint region_num() { return _region_num; }

   size_t total_capacity_bytes() {

     return (size_t) region_num() << HeapRegion::LogOfHRGrainBytes;

   }

   size_t total_used_bytes() { return _total_used_bytes; }

   virtual void verify();

   void verify_start();

   void verify_next_region(HeapRegion* hr);

   void verify_end();

 #if HEAP_REGION_SET_FORCE_VERIFY

   void verify_optional() {

     verify();

   }

 #else // HEAP_REGION_SET_FORCE_VERIFY

   void verify_optional() { }

 #endif // HEAP_REGION_SET_FORCE_VERIFY

   virtual void print_on(outputStream* out, bool print_contents = false);

 };

 // Customized err_msg for heap region sets. Apart from a

 // assert/guarantee-specific message it also prints out the values of

 // the fields of the associated set. This can be very helpful in

 // diagnosing failures.

 class hrs_ext_msg : public hrs_err_msg {

 public:

   hrs_ext_msg(HeapRegionSetBase* set, const char* message) : hrs_err_msg("") {

     set->fill_in_ext_msg(this, message);

   }

 };

 class HRSPhaseSetter {

 public:

   HRSPhaseSetter(HRSPhase phase) {

     HeapRegionSetBase::set_phase(phase);

   }

   ~HRSPhaseSetter() {

     HeapRegionSetBase::clear_phase();

   }

 };

 // These two macros are provided for convenience, to keep the uses of

 // these two asserts a bit more concise.

 #define hrs_assert_mt_safety_ok(_set_)                                        \

   do {                                                                        \

     assert((_set_)->check_mt_safety(), hrs_ext_msg((_set_), "MT safety"));    \

   } while (0)

 #define hrs_assert_region_ok(_set_, _hr_, _expected_)                         \

   do {                                                                        \

     assert((_set_)->verify_region((_hr_), (_expected_)),                      \

            hrs_ext_msg((_set_), "region verification"));                      \

   } while (0)

 //////////////////// HeapRegionSet ////////////////////

 #define hrs_assert_sets_match(_set1_, _set2_)                                 \

   do {                                                                        \

     assert(((_set1_)->regions_humongous() ==                                  \

                                             (_set2_)->regions_humongous()) && \

            ((_set1_)->regions_empty() == (_set2_)->regions_empty()),          \

            hrs_err_msg("the contents of set %s and set %s should match",      \

                        (_set1_)->name(), (_set2_)->name()));                  \

   } while (0)

 // This class represents heap region sets whose members are not

 // explicitly tracked. It's helpful to group regions using such sets

 // so that we can reason about all the region groups in the heap using

 // the same interface (namely, the HeapRegionSetBase API).

 class HeapRegionSet : public HeapRegionSetBase {

 protected:

   virtual const char* verify_region_extra(HeapRegion* hr) {

     if (hr->next() != NULL) {

       return "next() should always be NULL as we do not link the regions";

     }

     return HeapRegionSetBase::verify_region_extra(hr);

   }

   HeapRegionSet(const char* name) : HeapRegionSetBase(name) {

     clear();

   }

 public:

   // It adds hr to the set. The region should not be a member of

   // another set.

   inline void add(HeapRegion* hr);

   // It removes hr from the set. The region should be a member of

   // this set.

   inline void remove(HeapRegion* hr);

   // It removes a region from the set. Instead of updating the fields

   // of the set to reflect this removal, it accumulates the updates

   // in proxy_set. The idea is that proxy_set is thread-local to

   // avoid multiple threads updating the fields of the set

   // concurrently and having to synchronize. The method

   // update_from_proxy() will update the fields of the set from the

   // proxy_set.

   inline void remove_with_proxy(HeapRegion* hr, HeapRegionSet* proxy_set);

   // After multiple calls to remove_with_proxy() the updates to the

   // fields of the set are accumulated in proxy_set. This call

   // updates the fields of the set from proxy_set.

   void update_from_proxy(HeapRegionSet* proxy_set);

 };

 //////////////////// HeapRegionLinkedList ////////////////////

 // A set that links all the regions added to it in a singly-linked

 // list. We should try to avoid doing operations that iterate over

 // such lists in performance critical paths. Typically we should

 // add / remove one region at a time or concatenate two lists. All

 // those operations are done in constant time.

 class HeapRegionLinkedListIterator;

 class HeapRegionLinkedList : public HeapRegionSetBase {

   friend class HeapRegionLinkedListIterator;

 private:

   HeapRegion* _head;

   HeapRegion* _tail;

   // These are provided for use by the friend classes.

   HeapRegion* head() { return _head; }

   HeapRegion* tail() { return _tail; }

 protected:

   virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg);

   // See the comment for HeapRegionSetBase::clear()

   virtual void clear();

   HeapRegionLinkedList(const char* name) : HeapRegionSetBase(name) {

     clear();

   }

 public:

   // It adds hr to the list as the new head. The region should not be

   // a member of another set.

   inline void add_as_head(HeapRegion* hr);

   // It adds hr to the list as the new tail. The region should not be

   // a member of another set.

   inline void add_as_tail(HeapRegion* hr);

   // It removes and returns the head of the list. It assumes that the

   // list is not empty so it will return a non-NULL value.

   inline HeapRegion* remove_head();

   // Convenience method.

   inline HeapRegion* remove_head_or_null();

   // It moves the regions from from_list to this list and empties

   // from_list. The new regions will appear in the same order as they

   // were in from_list and be linked in the beginning of this list.

   void add_as_head(HeapRegionLinkedList* from_list);

   // It moves the regions from from_list to this list and empties

   // from_list. The new regions will appear in the same order as they

   // were in from_list and be linked in the end of this list.

   void add_as_tail(HeapRegionLinkedList* from_list);

   // It empties the list by removing all regions from it.

   void remove_all();

   // It removes all regions in the list that are pending for removal

   // (i.e., they have been tagged with "pending_removal"). The list

   // must not be empty, target_count should reflect the exact number

   // of regions that are pending for removal in the list, and

   // target_count should be > 1 (currently, we never need to remove a

   // single region using this).

   void remove_all_pending(uint target_count);

   virtual void verify();

   virtual void print_on(outputStream* out, bool print_contents = false);

 };

 //////////////////// HeapRegionLinkedListIterator ////////////////////

 // Iterator class that provides a convenient way to iterate over the

 // regions of a HeapRegionLinkedList instance.

 class HeapRegionLinkedListIterator : public StackObj {

 private:

   HeapRegionLinkedList* _list;

   HeapRegion*           _curr;

 public:

   bool more_available() {

     return _curr != NULL;

   }

   HeapRegion* get_next() {

     assert(more_available(),

            "get_next() should be called when more regions are available");

     // If we are going to introduce a count in the iterator we should

     // do the "cycle" check.

     HeapRegion* hr = _curr;

     assert(_list->verify_region(hr, _list), "region verification");

     _curr = hr->next();

     return hr;

   }

   HeapRegionLinkedListIterator(HeapRegionLinkedList* list)

     : _curr(NULL), _list(list) {

     _curr = list->head();

   }

 };

 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP