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_MEMORY_BLOCKOFFSETTABLE_HPP
26 #define SHARE_VM_MEMORY_BLOCKOFFSETTABLE_HPP
27
28 #include "memory/memRegion.hpp"
29 #include "memory/virtualspace.hpp"
30 #include "utilities/globalDefinitions.hpp"
31
32 // The CollectedHeap type requires subtypes to implement a method
33 // "block_start". For some subtypes, notably generational
34 // systems using card-table-based write barriers, the efficiency of this
35 // operation may be important. Implementations of the "BlockOffsetArray"
36 // class may be useful in providing such efficient implementations.
37 //
38 // BlockOffsetTable (abstract)
39 // - BlockOffsetArray (abstract)
40 // - BlockOffsetArrayNonContigSpace
41 // - BlockOffsetArrayContigSpace
42 //
43
44 class ContiguousSpace;
45
46 //////////////////////////////////////////////////////////////////////////
540 // In general, these methods expect to be called with
541 // [blk_start, blk_end) representing a block of memory in the heap.
542 // In this implementation, however, we are OK even if blk_start and/or
543 // blk_end are NULL because NULL is represented as 0, and thus
544 // never exceeds the "_next_offset_threshold".
545 void alloc_block(HeapWord* blk_start, HeapWord* blk_end) {
546 if (blk_end > _next_offset_threshold) {
547 alloc_block_work(blk_start, blk_end);
548 }
549 }
550 void alloc_block(HeapWord* blk, size_t size) {
551 alloc_block(blk, blk + size);
552 }
553
554 HeapWord* block_start_unsafe(const void* addr) const;
555
556 // Debugging support
557 virtual size_t last_active_index() const;
558 };
559
560 #endif // SHARE_VM_MEMORY_BLOCKOFFSETTABLE_HPP
|
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_SHARED_BLOCKOFFSETTABLE_HPP
26 #define SHARE_VM_GC_SHARED_BLOCKOFFSETTABLE_HPP
27
28 #include "memory/memRegion.hpp"
29 #include "memory/virtualspace.hpp"
30 #include "utilities/globalDefinitions.hpp"
31
32 // The CollectedHeap type requires subtypes to implement a method
33 // "block_start". For some subtypes, notably generational
34 // systems using card-table-based write barriers, the efficiency of this
35 // operation may be important. Implementations of the "BlockOffsetArray"
36 // class may be useful in providing such efficient implementations.
37 //
38 // BlockOffsetTable (abstract)
39 // - BlockOffsetArray (abstract)
40 // - BlockOffsetArrayNonContigSpace
41 // - BlockOffsetArrayContigSpace
42 //
43
44 class ContiguousSpace;
45
46 //////////////////////////////////////////////////////////////////////////
540 // In general, these methods expect to be called with
541 // [blk_start, blk_end) representing a block of memory in the heap.
542 // In this implementation, however, we are OK even if blk_start and/or
543 // blk_end are NULL because NULL is represented as 0, and thus
544 // never exceeds the "_next_offset_threshold".
545 void alloc_block(HeapWord* blk_start, HeapWord* blk_end) {
546 if (blk_end > _next_offset_threshold) {
547 alloc_block_work(blk_start, blk_end);
548 }
549 }
550 void alloc_block(HeapWord* blk, size_t size) {
551 alloc_block(blk, blk + size);
552 }
553
554 HeapWord* block_start_unsafe(const void* addr) const;
555
556 // Debugging support
557 virtual size_t last_active_index() const;
558 };
559
560 #endif // SHARE_VM_GC_SHARED_BLOCKOFFSETTABLE_HPP
|