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 /*

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  * 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_SHARED_MUTABLESPACE_HPP

 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_MUTABLESPACE_HPP

 #include "gc_implementation/shared/immutableSpace.hpp"

 #include "memory/memRegion.hpp"

 #include "utilities/copy.hpp"

 // A MutableSpace is a subtype of ImmutableSpace that supports the

 // concept of allocation. This includes the concepts that a space may

 // be only partially full, and the querry methods that go with such

 // an assumption. MutableSpace is also responsible for minimizing the

 // page allocation time by having the memory pretouched (with

 // AlwaysPretouch) and for optimizing page placement on NUMA systems

 // by make the underlying region interleaved (with UseNUMA).

 //

 // Invariant: (ImmutableSpace +) bottom() <= top() <= end()

 // top() is inclusive and end() is exclusive.

 class MutableSpaceMangler;

 class MutableSpace: public ImmutableSpace {

   friend class VMStructs;

   // Helper for mangling unused space in debug builds

   MutableSpaceMangler* _mangler;

   // The last region which page had been setup to be interleaved.

   MemRegion _last_setup_region;

   size_t _alignment;

  protected:

   HeapWord* _top;

   MutableSpaceMangler* mangler() { return _mangler; }

   void numa_setup_pages(MemRegion mr, bool clear_space);

   void pretouch_pages(MemRegion mr);

   void set_last_setup_region(MemRegion mr) { _last_setup_region = mr;   }

   MemRegion last_setup_region() const      { return _last_setup_region; }

  public:

   virtual ~MutableSpace();

   MutableSpace(size_t page_size);

   // Accessors

   HeapWord* top() const                    { return _top;    }

   virtual void set_top(HeapWord* value)    { _top = value;   }

   HeapWord** top_addr()                    { return &_top; }

   HeapWord** end_addr()                    { return &_end; }

   virtual void set_bottom(HeapWord* value) { _bottom = value; }

   virtual void set_end(HeapWord* value)    { _end = value; }

   size_t alignment()                       { return _alignment; }

   // Returns a subregion containing all objects in this space.

   MemRegion used_region() { return MemRegion(bottom(), top()); }

   static const bool SetupPages = true;

   static const bool DontSetupPages = false;

   // Initialization

   virtual void initialize(MemRegion mr,

                           bool clear_space,

                           bool mangle_space,

                           bool setup_pages = SetupPages);

   virtual void clear(bool mangle_space);

   // Does the usual initialization but optionally resets top to bottom.

 #if 0  // MANGLE_SPACE

   void initialize(MemRegion mr, bool clear_space, bool reset_top);

 #endif

   virtual void update() { }

   virtual void accumulate_statistics() { }

   // Methods used in mangling.  See descriptions under SpaceMangler.

   virtual void mangle_unused_area() PRODUCT_RETURN;

   virtual void mangle_unused_area_complete() PRODUCT_RETURN;

   virtual void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN;

   virtual void check_mangled_unused_area_complete() PRODUCT_RETURN;

   virtual void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN;

   // Used to save the space's current top for later use during mangling.

   virtual void set_top_for_allocations() PRODUCT_RETURN;

   virtual void ensure_parsability() { }

   virtual void mangle_region(MemRegion mr) PRODUCT_RETURN;

   // Boolean querries.

   bool is_empty() const              { return used_in_words() == 0; }

   bool not_empty() const             { return used_in_words() > 0; }

   bool contains(const void* p) const { return _bottom <= p && p < _end; }

   // Size computations.  Sizes are in bytes.

   size_t used_in_bytes() const                { return used_in_words() * HeapWordSize; }

   size_t free_in_bytes() const                { return free_in_words() * HeapWordSize; }

   // Size computations.  Sizes are in heapwords.

   virtual size_t used_in_words() const                    { return pointer_delta(top(), bottom()); }

   virtual size_t free_in_words() const                    { return pointer_delta(end(),    top()); }

   virtual size_t tlab_capacity(Thread* thr) const         { return capacity_in_bytes();            }

   virtual size_t unsafe_max_tlab_alloc(Thread* thr) const { return free_in_bytes();                }

   // Allocation (return NULL if full)

   virtual HeapWord* allocate(size_t word_size);

   virtual HeapWord* cas_allocate(size_t word_size);

   // Optional deallocation. Used in NUMA-allocator.

   bool cas_deallocate(HeapWord *obj, size_t size);

   // Iteration.

   void oop_iterate(ExtendedOopClosure* cl);

   void oop_iterate_no_header(OopClosure* cl);

   void object_iterate(ObjectClosure* cl);

   // Debugging

   virtual void print() const;

   virtual void print_on(outputStream* st) const;

   virtual void print_short() const;

   virtual void print_short_on(outputStream* st) const;

   virtual void verify();

 };

 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_MUTABLESPACE_HPP