1 /*
   2  * Copyright (c) 2013, 2017, Red Hat, Inc. and/or its affiliates.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGIONSET_HPP
  25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGIONSET_HPP
  26 
  27 #include "memory/allocation.hpp"
  28 
  29 class ShenandoahHeap;
  30 class ShenandoahHeapRegion;
  31 class ShenandoahHeapRegionSet;
  32 
  33 class ShenandoahHeapRegionSetIterator : public StackObj {
  34 private:
  35   const ShenandoahHeapRegionSet* _set;
  36   volatile jint _current_index;
  37   ShenandoahHeap* const _heap;
  38 
  39   // No implicit copying: iterators should be passed by reference to capture the state
  40   ShenandoahHeapRegionSetIterator(const ShenandoahHeapRegionSetIterator& that);
  41   ShenandoahHeapRegionSetIterator& operator=(const ShenandoahHeapRegionSetIterator& o);
  42 
  43 public:
  44   ShenandoahHeapRegionSetIterator(const ShenandoahHeapRegionSet* const set);
  45 
  46   // Reset existing iterator to new set
  47   void reset(const ShenandoahHeapRegionSet* const set);
  48 
  49   // MT version
  50   ShenandoahHeapRegion* claim_next();
  51 
  52   // Single-thread version
  53   ShenandoahHeapRegion* next();
  54 };
  55 
  56 class ShenandoahHeapRegionSet : public CHeapObj<mtGC> {
  57   friend class ShenandoahHeap;
  58 private:
  59   ShenandoahHeap* const _heap;
  60   size_t const          _map_size;
  61   size_t const          _region_size_bytes_shift;
  62   jbyte* const          _set_map;
  63   // Bias set map's base address for fast test if an oop is in set
  64   jbyte* const          _biased_set_map;
  65   size_t                _region_count;
  66 
  67 public:
  68 
  69   ShenandoahHeapRegionSet();
  70   ~ShenandoahHeapRegionSet();
  71 
  72   // Add region to set
  73   void add_region(ShenandoahHeapRegion* r);
  74   bool add_region_check_for_duplicates(ShenandoahHeapRegion* r);
  75 
  76   // Remove region from set
  77   void remove_region(ShenandoahHeapRegion* r);
  78 
  79   size_t count()  const { return _region_count; }
  80   bool is_empty() const { return _region_count == 0; }
  81 
  82   inline bool is_in(ShenandoahHeapRegion* r) const;
  83   inline bool is_in(size_t region_number)    const;
  84   inline bool is_in(HeapWord* p)             const;
  85 
  86   void print_on(outputStream* out) const;
  87 
  88   void clear();
  89 
  90 private:
  91   jbyte* biased_map_address() const {
  92     return _biased_set_map;
  93   }
  94 };
  95 
  96 #endif //SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGIONSET_HPP