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comparison src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp @ 20804:7848fc12602b

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Merge with jdk8u40-b25
author Gilles Duboscq <gilles.m.duboscq@oracle.com>
date Tue, 07 Apr 2015 14:58:49 +0200
parents ae52ee069062
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20184:84105dcdb05b 20804:7848fc12602b
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
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP
27
28 #include "memory/allocation.hpp"
29 #include "memory/memRegion.hpp"
30 #include "runtime/virtualspace.hpp"
31 #include "utilities/bitMap.hpp"
32
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;
45
46 // The commit/uncommit granularity in bytes.
47 size_t _page_size;
48
49 // Bitmap used for verification of commit/uncommit operations.
50 BitMap _committed;
51
52 // Bitmap used to keep track of which pages are dirty or not for _special
53 // spaces. This is needed because for those spaces the underlying memory
54 // will only be zero filled the first time it is committed. Calls to commit
55 // will use this bitmap and return whether or not the memory is zero filled.
56 BitMap _dirty;
57
58 // Indicates that the entire space has been committed and pinned in memory,
59 // os::commit_memory() or os::uncommit_memory() have no function.
60 bool _special;
61
62 // Indicates whether the committed space should be executable.
63 bool _executable;
64
65 // Returns the index of the page which contains the given address.
66 uintptr_t addr_to_page_index(char* addr) const;
67 // Returns the address of the given page index.
68 char* page_start(uintptr_t index);
69 // Returns the byte size of the given number of pages.
70 size_t byte_size_for_pages(size_t num);
71
72 // Returns true if the entire area is backed by committed memory.
73 bool is_area_committed(uintptr_t start, size_t size_in_pages) const;
74 // Returns true if the entire area is not backed by committed memory.
75 bool is_area_uncommitted(uintptr_t start, size_t size_in_pages) const;
76
77 public:
78
79 // Commit the given area of pages starting at start being size_in_pages large.
80 // Returns true if the given area is zero filled upon completion.
81 bool commit(uintptr_t start, size_t size_in_pages);
82
83 // Uncommit the given area of pages starting at start being size_in_pages large.
84 void uncommit(uintptr_t start, size_t size_in_pages);
85
86 // Initialization
87 G1PageBasedVirtualSpace();
88 bool initialize_with_granularity(ReservedSpace rs, size_t page_size);
89
90 // Destruction
91 ~G1PageBasedVirtualSpace();
92
93 // Amount of reserved memory.
94 size_t reserved_size() const;
95 // Memory used in this virtual space.
96 size_t committed_size() const;
97 // Memory left to use/expand in this virtual space.
98 size_t uncommitted_size() const;
99
100 bool contains(const void* p) const;
101
102 MemRegion reserved() {
103 MemRegion x((HeapWord*)_low_boundary, reserved_size() / HeapWordSize);
104 return x;
105 }
106
107 void release();
108
109 void check_for_contiguity() PRODUCT_RETURN;
110
111 // Debugging
112 void print_on(outputStream* out) PRODUCT_RETURN;
113 void print();
114 };
115
116 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP