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comparison src/share/vm/memory/cardTableModRefBS.cpp @ 12355:cefad50507d8

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Merge with hs25-b53
author Gilles Duboscq <duboscq@ssw.jku.at>
date Fri, 11 Oct 2013 10:38:03 +0200
parents d55c004e1d4d
children 63a4eb8bcd23 3205e78d8193
comparison
equal deleted inserted replaced
12058:ccb4f2af2319 12355:cefad50507d8
421 421
422 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal) { 422 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal) {
423 inline_write_ref_field(field, newVal); 423 inline_write_ref_field(field, newVal);
424 } 424 }
425 425
426 /*
427 Claimed and deferred bits are used together in G1 during the evacuation
428 pause. These bits can have the following state transitions:
429 1. The claimed bit can be put over any other card state. Except that
430 the "dirty -> dirty and claimed" transition is checked for in
431 G1 code and is not used.
432 2. Deferred bit can be set only if the previous state of the card
433 was either clean or claimed. mark_card_deferred() is wait-free.
434 We do not care if the operation is be successful because if
435 it does not it will only result in duplicate entry in the update
436 buffer because of the "cache-miss". So it's not worth spinning.
437 */
438
439
440 bool CardTableModRefBS::claim_card(size_t card_index) {
441 jbyte val = _byte_map[card_index];
442 assert(val != dirty_card_val(), "Shouldn't claim a dirty card");
443 while (val == clean_card_val() ||
444 (val & (clean_card_mask_val() | claimed_card_val())) != claimed_card_val()) {
445 jbyte new_val = val;
446 if (val == clean_card_val()) {
447 new_val = (jbyte)claimed_card_val();
448 } else {
449 new_val = val | (jbyte)claimed_card_val();
450 }
451 jbyte res = Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
452 if (res == val) {
453 return true;
454 }
455 val = res;
456 }
457 return false;
458 }
459
460 bool CardTableModRefBS::mark_card_deferred(size_t card_index) {
461 jbyte val = _byte_map[card_index];
462 // It's already processed
463 if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) {
464 return false;
465 }
466 // Cached bit can be installed either on a clean card or on a claimed card.
467 jbyte new_val = val;
468 if (val == clean_card_val()) {
469 new_val = (jbyte)deferred_card_val();
470 } else {
471 if (val & claimed_card_val()) {
472 new_val = val | (jbyte)deferred_card_val();
473 }
474 }
475 if (new_val != val) {
476 Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
477 }
478 return true;
479 }
480 426
481 void CardTableModRefBS::non_clean_card_iterate_possibly_parallel(Space* sp, 427 void CardTableModRefBS::non_clean_card_iterate_possibly_parallel(Space* sp,
482 MemRegion mr, 428 MemRegion mr,
483 OopsInGenClosure* cl, 429 OopsInGenClosure* cl,
484 CardTableRS* ct) { 430 CardTableRS* ct) {