Mercurial > hg > truffle
comparison src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp @ 20337:1f1d373cd044
8038423: G1: Decommit memory within heap
Summary: Allow G1 to decommit memory of arbitrary regions within the heap and their associated auxiliary data structures card table, BOT, hot card cache, and mark bitmaps.
Reviewed-by: mgerdin, brutisso, jwilhelm
author | tschatzl |
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date | Thu, 21 Aug 2014 11:47:10 +0200 |
parents | |
children | ae52ee069062 |
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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 // 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; | |
55 | |
56 // Indicates whether the committed space should be executable. | |
57 bool _executable; | |
58 | |
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); | |
65 | |
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; | |
70 | |
71 public: | |
72 | |
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); | |
75 | |
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); | |
78 | |
79 bool special() const { return _special; } | |
80 | |
81 // Initialization | |
82 G1PageBasedVirtualSpace(); | |
83 bool initialize_with_granularity(ReservedSpace rs, size_t page_size); | |
84 | |
85 // Destruction | |
86 ~G1PageBasedVirtualSpace(); | |
87 | |
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; | |
94 | |
95 bool contains(const void* p) const; | |
96 | |
97 MemRegion reserved() { | |
98 MemRegion x((HeapWord*)_low_boundary, reserved_size() / HeapWordSize); | |
99 return x; | |
100 } | |
101 | |
102 void release(); | |
103 | |
104 void check_for_contiguity() PRODUCT_RETURN; | |
105 | |
106 // Debugging | |
107 void print_on(outputStream* out) PRODUCT_RETURN; | |
108 void print(); | |
109 }; | |
110 | |
111 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP |