Mercurial > hg > truffle
diff src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp @ 187:790e66e5fbac
6687581: Make CMS work with compressed oops
Summary: Make FreeChunk read markword instead of LSB in _klass pointer to indicate that it's a FreeChunk for compressed oops.
Reviewed-by: ysr, jmasa
author | coleenp |
---|---|
date | Mon, 09 Jun 2008 11:51:19 -0400 |
parents | b5489bb705c9 |
children | d1605aabd0a1 6aae2f9d0294 |
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--- a/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Fri Jun 06 11:47:26 2008 -0700 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Mon Jun 09 11:51:19 2008 -0400 @@ -190,7 +190,8 @@ // depends on this property. debug_only( FreeChunk* junk = NULL; - assert(junk->prev_addr() == (void*)(oop(junk)->klass_addr()), + assert(UseCompressedOops || + junk->prev_addr() == (void*)(oop(junk)->klass_addr()), "Offset of FreeChunk::_prev within FreeChunk must match" " that of OopDesc::_klass within OopDesc"); ) @@ -1039,7 +1040,7 @@ // mark end of object } // check that oop looks uninitialized - assert(oop(start)->klass() == NULL, "_klass should be NULL"); + assert(oop(start)->klass_or_null() == NULL, "_klass should be NULL"); } void CMSCollector::promoted(bool par, HeapWord* start, @@ -1309,17 +1310,25 @@ } } oop obj = oop(obj_ptr); - assert(obj->klass() == NULL, "Object should be uninitialized here."); + assert(obj->klass_or_null() == NULL, "Object should be uninitialized here."); // Otherwise, copy the object. Here we must be careful to insert the // klass pointer last, since this marks the block as an allocated object. + // Except with compressed oops it's the mark word. HeapWord* old_ptr = (HeapWord*)old; if (word_sz > (size_t)oopDesc::header_size()) { Copy::aligned_disjoint_words(old_ptr + oopDesc::header_size(), obj_ptr + oopDesc::header_size(), word_sz - oopDesc::header_size()); } + + if (UseCompressedOops) { + // Copy gap missed by (aligned) header size calculation above + obj->set_klass_gap(old->klass_gap()); + } + // Restore the mark word copied above. obj->set_mark(m); + // Now we can track the promoted object, if necessary. We take care // To delay the transition from uninitialized to full object // (i.e., insertion of klass pointer) until after, so that it @@ -1327,7 +1336,8 @@ if (promoInfo->tracking()) { promoInfo->track((PromotedObject*)obj, old->klass()); } - // Finally, install the klass pointer. + + // Finally, install the klass pointer (this should be volatile). obj->set_klass(old->klass()); assert(old->is_oop(), "Will dereference klass ptr below"); @@ -6165,7 +6175,7 @@ HeapWord* CMSCollector::next_card_start_after_block(HeapWord* addr) const { size_t sz = 0; oop p = (oop)addr; - if (p->klass() != NULL && p->is_parsable()) { + if (p->klass_or_null() != NULL && p->is_parsable()) { sz = CompactibleFreeListSpace::adjustObjectSize(p->size()); } else { sz = block_size_using_printezis_bits(addr); @@ -6602,7 +6612,7 @@ } if (_bitMap->isMarked(addr)) { // it's marked; is it potentially uninitialized? - if (p->klass() != NULL) { + if (p->klass_or_null() != NULL) { if (CMSPermGenPrecleaningEnabled && !p->is_parsable()) { // Signal precleaning to redirty the card since // the klass pointer is already installed. @@ -6615,11 +6625,8 @@ if (p->is_objArray()) { // objArrays are precisely marked; restrict scanning // to dirty cards only. - size = p->oop_iterate(_scanningClosure, mr); - assert(size == CompactibleFreeListSpace::adjustObjectSize(size), - "adjustObjectSize should be the identity for array sizes, " - "which are necessarily larger than minimum object size of " - "two heap words"); + size = CompactibleFreeListSpace::adjustObjectSize( + p->oop_iterate(_scanningClosure, mr)); } else { // A non-array may have been imprecisely marked; we need // to scan object in its entirety. @@ -6653,7 +6660,7 @@ } } else { // Either a not yet marked object or an uninitialized object - if (p->klass() == NULL || !p->is_parsable()) { + if (p->klass_or_null() == NULL || !p->is_parsable()) { // An uninitialized object, skip to the next card, since // we may not be able to read its P-bits yet. assert(size == 0, "Initial value"); @@ -6710,7 +6717,7 @@ HeapWord* addr = (HeapWord*)p; DEBUG_ONLY(_collector->verify_work_stacks_empty();) assert(!_span.contains(addr), "we are scanning the survivor spaces"); - assert(p->klass() != NULL, "object should be initializd"); + assert(p->klass_or_null() != NULL, "object should be initializd"); assert(p->is_parsable(), "must be parsable."); // an initialized object; ignore mark word in verification below // since we are running concurrent with mutators @@ -6868,7 +6875,7 @@ assert(_skipBits == 0, "tautology"); _skipBits = 2; // skip next two marked bits ("Printezis-marks") oop p = oop(addr); - if (p->klass() == NULL || !p->is_parsable()) { + if (p->klass_or_null() == NULL || !p->is_parsable()) { DEBUG_ONLY(if (!_verifying) {) // We re-dirty the cards on which this object lies and increase // the _threshold so that we'll come back to scan this object @@ -6890,7 +6897,7 @@ if (_threshold < end_card_addr) { _threshold = end_card_addr; } - if (p->klass() != NULL) { + if (p->klass_or_null() != NULL) { // Redirty the range of cards... _mut->mark_range(redirty_range); } // ...else the setting of klass will dirty the card anyway. @@ -7048,7 +7055,7 @@ assert(_skip_bits == 0, "tautology"); _skip_bits = 2; // skip next two marked bits ("Printezis-marks") oop p = oop(addr); - if (p->klass() == NULL || !p->is_parsable()) { + if (p->klass_or_null() == NULL || !p->is_parsable()) { // in the case of Clean-on-Enter optimization, redirty card // and avoid clearing card by increasing the threshold. return; @@ -8023,7 +8030,7 @@ "alignment problem"); #ifdef DEBUG - if (oop(addr)->klass() != NULL && + if (oop(addr)->klass_or_null() != NULL && ( !_collector->should_unload_classes() || oop(addr)->is_parsable())) { // Ignore mark word because we are running concurrent with mutators @@ -8036,7 +8043,7 @@ } else { // This should be an initialized object that's alive. - assert(oop(addr)->klass() != NULL && + assert(oop(addr)->klass_or_null() != NULL && (!_collector->should_unload_classes() || oop(addr)->is_parsable()), "Should be an initialized object");