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
|
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 // For systems that only commits of memory in a given size (always greater than
38 // page size) the base address is required to be aligned to that page size.
39 // The actual size requested need not be aligned to that page size, but the size
40 // of the reservation passed may be rounded up to this page size. Any fragment
41 // (less than the page size) of the actual size at the tail of the request will
42 // be committed using OS small pages.
43 // The implementation gives an error when trying to commit or uncommit pages that
44 // have already been committed or uncommitted.
45 class G1PageBasedVirtualSpace VALUE_OBJ_CLASS_SPEC {
46 friend class VMStructs;
47 private:
48 // Reserved area addresses.
49 char* _low_boundary;
50 char* _high_boundary;
51
52 // The size of the tail in bytes of the handled space that needs to be committed
53 // using small pages.
54 size_t _tail_size;
55
56 // The preferred page size used for commit/uncommit in bytes.
57 size_t _page_size;
58
59 // Bitmap used for verification of commit/uncommit operations.
60 BitMap _committed;
61
62 // Bitmap used to keep track of which pages are dirty or not for _special
63 // spaces. This is needed because for those spaces the underlying memory
64 // will only be zero filled the first time it is committed. Calls to commit
65 // will use this bitmap and return whether or not the memory is zero filled.
66 BitMap _dirty;
67
68 // Indicates that the entire space has been committed and pinned in memory,
69 // os::commit_memory() or os::uncommit_memory() have no function.
70 bool _special;
71
72 // Indicates whether the committed space should be executable.
73 bool _executable;
74
75 // Helper function for committing memory. Commit the given memory range by using
76 // _page_size pages as much as possible and the remainder with small sized pages.
77 void commit_internal(size_t start_page, size_t end_page);
78 // Commit num_pages pages of _page_size size starting from start. All argument
79 // checking has been performed.
80 void commit_preferred_pages(size_t start_page, size_t end_page);
81 // Commit space at the high end of the space that needs to be committed with small
82 // sized pages.
83 void commit_tail();
84
85 // Uncommit the given memory range.
86 void uncommit_internal(size_t start_page, size_t end_page);
87
88 // Pretouch the given memory range.
89 void pretouch_internal(size_t start_page, size_t end_page);
90
91 // Returns the index of the page which contains the given address.
92 uintptr_t addr_to_page_index(char* addr) const;
93 // Returns the address of the given page index.
94 char* page_start(size_t index) const;
95
96 // Is the given page index the last page?
97 bool is_last_page(size_t index) const { return index == (_committed.size() - 1); }
98 // Is the given page index the first after last page?
99 bool is_after_last_page(size_t index) const;
100 // Is the last page only partially covered by this space?
101 bool is_last_page_partial() const { return !is_ptr_aligned(_high_boundary, _page_size); }
102 // Returns the end address of the given page bounded by the reserved space.
103 char* bounded_end_addr(size_t end_page) const;
104
105 // Returns true if the entire area is backed by committed memory.
106 bool is_area_committed(size_t start_page, size_t size_in_pages) const;
107 // Returns true if the entire area is not backed by committed memory.
108 bool is_area_uncommitted(size_t start_page, size_t size_in_pages) const;
109
110 void initialize_with_page_size(ReservedSpace rs, size_t used_size, size_t page_size);
111 public:
112
113 // Commit the given area of pages starting at start being size_in_pages large.
114 // Returns true if the given area is zero filled upon completion.
115 bool commit(size_t start_page, size_t size_in_pages);
116
117 // Uncommit the given area of pages starting at start being size_in_pages large.
118 void uncommit(size_t start_page, size_t size_in_pages);
119
120 // Initialize the given reserved space with the given base address and the size
121 // actually used.
122 // Prefer to commit in page_size chunks.
123 G1PageBasedVirtualSpace(ReservedSpace rs, size_t used_size, size_t page_size);
124
125 // Destruction
126 ~G1PageBasedVirtualSpace();
127
128 // Amount of reserved memory.
129 size_t reserved_size() const;
130 // Memory used in this virtual space.
131 size_t committed_size() const;
132 // Memory left to use/expand in this virtual space.
133 size_t uncommitted_size() const;
134
135 bool contains(const void* p) const;
136
137 MemRegion reserved() {
138 MemRegion x((HeapWord*)_low_boundary, reserved_size() / HeapWordSize);
139 return x;
140 }
141
142 void release();
143
|