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 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
26 // enumerate ref fields that have been modified (since the last
27 // enumeration.)
28
29 // As it currently stands, this barrier is *imprecise*: when a ref field in
30 // an object "o" is modified, the card table entry for the card containing
31 // the head of "o" is dirtied, not necessarily the card containing the
32 // modified field itself. For object arrays, however, the barrier *is*
33 // precise; only the card containing the modified element is dirtied.
34 // Any MemRegionClosures used to scan dirty cards should take these
35 // considerations into account.
36
37 class Generation;
38 class OopsInGenClosure;
39 class DirtyCardToOopClosure;
40
41 class CardTableModRefBS: public ModRefBarrierSet {
42 // Some classes get to look at some private stuff.
43 friend class BytecodeInterpreter;
44 friend class VMStructs;
473 return CardsPerStrideChunk * card_size_in_words;
474 }
475
476 };
477
478 class CardTableRS;
479
480 // A specialization for the CardTableRS gen rem set.
481 class CardTableModRefBSForCTRS: public CardTableModRefBS {
482 CardTableRS* _rs;
483 protected:
484 bool card_will_be_scanned(jbyte cv);
485 bool card_may_have_been_dirty(jbyte cv);
486 public:
487 CardTableModRefBSForCTRS(MemRegion whole_heap,
488 int max_covered_regions) :
489 CardTableModRefBS(whole_heap, max_covered_regions) {}
490
491 void set_CTRS(CardTableRS* rs) { _rs = rs; }
492 };
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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_CARDTABLEMODREFBS_HPP
26 #define SHARE_VM_MEMORY_CARDTABLEMODREFBS_HPP
27
28 #include "memory/modRefBarrierSet.hpp"
29 #include "oops/oop.hpp"
30 #include "oops/oop.inline2.hpp"
31
32 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
33 // enumerate ref fields that have been modified (since the last
34 // enumeration.)
35
36 // As it currently stands, this barrier is *imprecise*: when a ref field in
37 // an object "o" is modified, the card table entry for the card containing
38 // the head of "o" is dirtied, not necessarily the card containing the
39 // modified field itself. For object arrays, however, the barrier *is*
40 // precise; only the card containing the modified element is dirtied.
41 // Any MemRegionClosures used to scan dirty cards should take these
42 // considerations into account.
43
44 class Generation;
45 class OopsInGenClosure;
46 class DirtyCardToOopClosure;
47
48 class CardTableModRefBS: public ModRefBarrierSet {
49 // Some classes get to look at some private stuff.
50 friend class BytecodeInterpreter;
51 friend class VMStructs;
480 return CardsPerStrideChunk * card_size_in_words;
481 }
482
483 };
484
485 class CardTableRS;
486
487 // A specialization for the CardTableRS gen rem set.
488 class CardTableModRefBSForCTRS: public CardTableModRefBS {
489 CardTableRS* _rs;
490 protected:
491 bool card_will_be_scanned(jbyte cv);
492 bool card_may_have_been_dirty(jbyte cv);
493 public:
494 CardTableModRefBSForCTRS(MemRegion whole_heap,
495 int max_covered_regions) :
496 CardTableModRefBS(whole_heap, max_covered_regions) {}
497
498 void set_CTRS(CardTableRS* rs) { _rs = rs; }
499 };
500
501 #endif // SHARE_VM_MEMORY_CARDTABLEMODREFBS_HPP
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