1 /*

     2  * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.

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

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP

    26 #define SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP

    27 

    28 #include "gc/g1/g1PageBasedVirtualSpace.hpp"

    29 #include "memory/allocation.hpp"

    30 #include "utilities/debug.hpp"

    31 

    32 class G1MappingChangedListener VALUE_OBJ_CLASS_SPEC {

    33  public:

    34   // Fired after commit of the memory, i.e. the memory this listener is registered

    35   // for can be accessed.

    36   // Zero_filled indicates that the memory can be considered as filled with zero bytes

    37   // when called.

    38   virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled) = 0;

    39 };

    40 

    41 // Maps region based commit/uncommit requests to the underlying page sized virtual

    42 // space.

    43 class G1RegionToSpaceMapper : public CHeapObj<mtGC> {

    44  private:

    45   G1MappingChangedListener* _listener;

    46  protected:

    47   // Backing storage.

    48   G1PageBasedVirtualSpace _storage;

    49 

    50   size_t _region_granularity;

    51   // Mapping management

    52   BitMap _commit_map;

    53 

    54   G1RegionToSpaceMapper(ReservedSpace rs, size_t used_size, size_t page_size, size_t region_granularity, MemoryType type);

    55 

    56   void fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled);

    57  public:

    58   MemRegion reserved() { return _storage.reserved(); }

    59 

    60   size_t reserved_size() { return _storage.reserved_size(); }

    61   size_t committed_size() { return _storage.committed_size(); }

    62 

    63   void set_mapping_changed_listener(G1MappingChangedListener* listener) { _listener = listener; }

    64 

    65   virtual ~G1RegionToSpaceMapper() {

    66     _commit_map.resize(0, /* in_resource_area */ false);

    67   }

    68 

    69   bool is_committed(uintptr_t idx) const {

    70     return _commit_map.at(idx);

    71   }

    72 

    73   virtual void commit_regions(uint start_idx, size_t num_regions = 1) = 0;

    74   virtual void uncommit_regions(uint start_idx, size_t num_regions = 1) = 0;

    75 

    76   // Creates an appropriate G1RegionToSpaceMapper for the given parameters.

    77   // The actual space to be used within the given reservation is given by actual_size.

    78   // This is because some OSes need to round up the reservation size to guarantee

    79   // alignment of page_size.

    80   // The byte_translation_factor defines how many bytes in a region correspond to

    81   // a single byte in the data structure this mapper is for.

    82   // Eg. in the card table, this value corresponds to the size a single card

    83   // table entry corresponds to in the heap.

    84   static G1RegionToSpaceMapper* create_mapper(ReservedSpace rs,

    85                                               size_t actual_size,

    86                                               size_t page_size,

    87                                               size_t region_granularity,

    88                                               size_t byte_translation_factor,

    89                                               MemoryType type);

    90 };

    91 

    92 #endif /* SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP */