truffle: src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp comparison

comparison 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

comparison

equal deleted inserted replaced

-:8759d37f2524
+:790e66e5fbac
 // Verify the assumption that FreeChunk::_prev and OopDesc::_klass
 // offsets match. The ability to tell free chunks from objects
 // 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");
 )
 if (ParallelGCThreads > 0) {
 typedef CMSParGCThreadState* CMSParGCThreadStatePtr;
 _markBitMap.mark(start + 1);      // object is potentially uninitialized?
 _markBitMap.mark(start + size - 1);
 // 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,
 bool is_obj_array, size_t obj_size) {
 assert(_markBitMap.covers(start), "Out of bounds");
 if (obj_ptr == NULL) {
 return NULL;
 }
 }
 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
 // atomically becomes a promoted object.
 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");
 collector()->promoted(true,          // parallel
 obj_ptr, old->is_objArray(), word_sz);
 }
 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);
 }
 assert(sz > 0, "size must be nonzero");
 // and we have been asked to abort this ongoing preclean cycle.
 return 0;
 }
 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.
 assert(size == 0, "Initial value");
 } else {
 // since we are running concurrent with mutators
 assert(p->is_oop(true), "should be an oop");
 if (p->is_objArray()) {
 // objArrays are precisely marked; restrict scanning
 // to dirty cards only.
-size = p->oop_iterate(_scanningClosure, mr);
+size = CompactibleFreeListSpace::adjustObjectSize(
-assert(size == CompactibleFreeListSpace::adjustObjectSize(size),
+p->oop_iterate(_scanningClosure, mr));
-"adjustObjectSize should be the identity for array sizes, "
-"which are necessarily larger than minimum object size of "
-"two heap words");
 } else {
 // A non-array may have been imprecisely marked; we need
 // to scan object in its entirety.
 size = CompactibleFreeListSpace::adjustObjectSize(
 p->oop_iterate(_scanningClosure));
 // will dirty the card when the klass pointer is installed in the
 // object (signalling the completion of initialization).
 }
 } 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");
 } else {
 // An object not (yet) reached by marking: we merely need to
 size_t SurvivorSpacePrecleanClosure::do_object_careful(oop p) {
 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
 assert(p->is_oop(true), "should be an oop");
 // Note that we do not yield while we iterate over
 if (_bitMap->isMarked(addr+1)) {
 // this is an allocated but not yet initialized object
 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
 // during the preclean or remark phase. (CMSCleanOnEnter)
 if (CMSCleanOnEnter) {
 assert(_threshold <= end_card_addr,
 "Because we are just scanning into this object");
 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.
 }
 DEBUG_ONLY(})
 if (_bit_map->isMarked(addr+1)) {
 // this is an allocated object that might not yet be initialized
 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;
 }
 }
 size = pointer_delta(nextOneAddr + 1, addr);
 assert(size == CompactibleFreeListSpace::adjustObjectSize(size),
 "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
 assert(oop(addr)->is_oop(true), "live block should be an oop");
 assert(size ==
 }
 #endif
 } 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");
 // Ignore mark word because we are running concurrent with mutators
 assert(oop(addr)->is_oop(true), "live block should be an oop");

Mercurial > hg > truffle

comparison src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp @ 187:790e66e5fbac