jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp@c2844108a708

     1 /*

     2  * Copyright (c) 2014, 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

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    25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP

    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP

    28 #include "memory/allocation.hpp"

    29 #include "memory/memRegion.hpp"

    30 #include "runtime/virtualspace.hpp"

    31 #include "utilities/bitMap.hpp"

    33 // Virtual space management helper for a virtual space with an OS page allocation

    34 // granularity.

    35 // (De-)Allocation requests are always OS page aligned by passing a page index

    36 // and multiples of pages.

    37 // The implementation gives an error when trying to commit or uncommit pages that

    38 // have already been committed or uncommitted.

    39 class G1PageBasedVirtualSpace VALUE_OBJ_CLASS_SPEC {

    40   friend class VMStructs;

    41  private:

    42   // Reserved area addresses.

    43   char* _low_boundary;

    44   char* _high_boundary;

    46   // The commit/uncommit granularity in bytes.

    47   size_t _page_size;

    49   // Bitmap used for verification of commit/uncommit operations.

    50   BitMap _committed;

    52   // Indicates that the entire space has been committed and pinned in memory,

    53   // os::commit_memory() or os::uncommit_memory() have no function.

    54   bool _special;

    56   // Indicates whether the committed space should be executable.

    57   bool _executable;

    59   // Returns the index of the page which contains the given address.

    60   uintptr_t  addr_to_page_index(char* addr) const;

    61   // Returns the address of the given page index.

    62   char*  page_start(uintptr_t index);

    63   // Returns the byte size of the given number of pages.

    64   size_t byte_size_for_pages(size_t num);

    66   // Returns true if the entire area is backed by committed memory.

    67   bool is_area_committed(uintptr_t start, size_t size_in_pages) const;

    68   // Returns true if the entire area is not backed by committed memory.

    69   bool is_area_uncommitted(uintptr_t start, size_t size_in_pages) const;

    71  public:

    73   // Commit the given area of pages starting at start being size_in_pages large.

    74   MemRegion commit(uintptr_t start, size_t size_in_pages);

    76   // Uncommit the given area of pages starting at start being size_in_pages large.

    77   MemRegion uncommit(uintptr_t start, size_t size_in_pages);

    79   bool special() const { return _special; }

    81   // Initialization

    82   G1PageBasedVirtualSpace();

    83   bool initialize_with_granularity(ReservedSpace rs, size_t page_size);

    85   // Destruction

    86   ~G1PageBasedVirtualSpace();

    88   // Amount of reserved memory.

    89   size_t reserved_size() const;

    90   // Memory used in this virtual space.

    91   size_t committed_size() const;

    92   // Memory left to use/expand in this virtual space.

    93   size_t uncommitted_size() const;

    95   bool contains(const void* p) const;

    97   MemRegion reserved() {

    98     MemRegion x((HeapWord*)_low_boundary, reserved_size() / HeapWordSize);

    99     return x;

   100   }

   102   void release();

   104   void check_for_contiguity() PRODUCT_RETURN;

   106   // Debugging

   107   void print_on(outputStream* out) PRODUCT_RETURN;

   108   void print();

   109 };

   111 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP

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