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 /*

  * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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  * 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

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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

 class hrs_ext_msg;

 class HRSMtSafeChecker : public CHeapObj<mtGC> {

 public:

   virtual void check() = 0;

 };

 class MasterFreeRegionListMtSafeChecker    : public HRSMtSafeChecker { public: void check(); };

 class SecondaryFreeRegionListMtSafeChecker : public HRSMtSafeChecker { public: void check(); };

 class HumongousRegionSetMtSafeChecker      : public HRSMtSafeChecker { public: void check(); };

 class OldRegionSetMtSafeChecker            : public HRSMtSafeChecker { public: void check(); };

 class HeapRegionSetCount VALUE_OBJ_CLASS_SPEC {

   friend class VMStructs;

   uint   _length;

   size_t _capacity;

 public:

   HeapRegionSetCount() : _length(0), _capacity(0) { }

   const uint   length()   const { return _length;   }

   const size_t capacity() const { return _capacity; }

   void increment(uint length_to_add, size_t capacity_to_add) {

     _length += length_to_add;

     _capacity += capacity_to_add;

   }

   void decrement(const uint length_to_remove, const size_t capacity_to_remove) {

     _length -= length_to_remove;

     _capacity -= capacity_to_remove;

   }

 };

 // 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 HeapRegionSetBase VALUE_OBJ_CLASS_SPEC {

   friend class VMStructs;

 private:

   bool _is_humongous;

   bool _is_empty;

   HRSMtSafeChecker* _mt_safety_checker;

 protected:

   // 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.

   HeapRegionSetCount _count;

   const char* _name;

   bool _verify_in_progress;

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

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

   void verify_region(HeapRegion* hr) PRODUCT_RETURN;

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

   // not. Only used during verification.

   bool regions_humongous() { return _is_humongous; }

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

   // not. Only used during verification.

   bool regions_empty() { return _is_empty; }

   void check_mt_safety() {

     if (_mt_safety_checker != NULL) {

       _mt_safety_checker->check();

     }

   }

   virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg) { }

   HeapRegionSetBase(const char* name, bool humongous, bool empty, HRSMtSafeChecker* mt_safety_checker);

 public:

   const char* name() { return _name; }

   uint length() const { return _count.length(); }

   bool is_empty() { return _count.length() == 0; }

   size_t total_capacity_bytes() {

     return _count.capacity();

   }

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

   // the set and tags the region appropriately.

   inline void add(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(HeapRegion* hr);

   // 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.

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

   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("%s", "") {

     set->fill_in_ext_msg(this, message);

   }

 };

 #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 {

 public:

   HeapRegionSet(const char* name, bool humongous, HRSMtSafeChecker* mt_safety_checker):

     HeapRegionSetBase(name, humongous, false /* empty */, mt_safety_checker) { }

   void bulk_remove(const HeapRegionSetCount& removed) {

     _count.decrement(removed.length(), removed.capacity());

   }

 };

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

 // sorted 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.

 class FreeRegionListIterator;

 class FreeRegionList : public HeapRegionSetBase {

   friend class FreeRegionListIterator;

 private:

   HeapRegion* _head;

   HeapRegion* _tail;

   // _last is used to keep track of where we added an element the last

   // time. It helps to improve performance when adding several ordered items in a row.

   HeapRegion* _last;

   static uint _unrealistically_long_length;

   inline HeapRegion* remove_from_head_impl();

   inline HeapRegion* remove_from_tail_impl();

 protected:

   virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg);

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

   virtual void clear();

 public:

   FreeRegionList(const char* name, HRSMtSafeChecker* mt_safety_checker = NULL):

     HeapRegionSetBase(name, false /* humongous */, true /* empty */, mt_safety_checker) {

     clear();

   }

   void verify_list();

 #ifdef ASSERT

   bool contains(HeapRegion* hr) const {

     return hr->containing_set() == this;

   }

 #endif

   static void set_unrealistically_long_length(uint len);

   // Add hr to the list. The region should not be a member of another set.

   // Assumes that the list is ordered and will preserve that order. The order

   // is determined by hrm_index.

   inline void add_ordered(HeapRegion* hr);

   // Removes from head or tail based on the given argument.

   HeapRegion* remove_region(bool from_head);

   // Merge two ordered lists. The result is also ordered. The order is

   // determined by hrm_index.

   void add_ordered(FreeRegionList* from_list);

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

   void remove_all();

   // Remove all (contiguous) regions from first to first + num_regions -1 from

   // this list.

   // Num_regions must be > 1.

   void remove_starting_at(HeapRegion* first, uint num_regions);

   virtual void verify();

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

 };

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

 // regions of a FreeRegionList.

 class FreeRegionListIterator : public StackObj {

 private:

   FreeRegionList* _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;

     _list->verify_region(hr);

     _curr = hr->next();

     return hr;

   }

   FreeRegionListIterator(FreeRegionList* list) : _curr(NULL), _list(list) {

     _curr = list->_head;

   }

 };

 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP