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6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"

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The CMS concurrent precleaning and concurrent marking phases should work around classes that are undergoing redefinition.

Reviewed-by: ysr, dcubed
This commit is contained in:
Jon Masamitsu 2009-01-11 16:58:24 -08:00
parent 3474623106
commit c2ff9781c7
18 changed files with 161 additions and 19 deletions
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19
hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp
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@ -6633,7 +6633,11 @@ size_t ScanMarkedObjectsAgainCarefullyClosure::do_object_careful_m(
if (_bitMap->isMarked(addr)) {
// it's marked; is it potentially uninitialized?
if (p->klass_or_null() != NULL) {
if (CMSPermGenPrecleaningEnabled && !p->is_parsable()) {
// If is_conc_safe is false, the object may be undergoing
// change by the VM outside a safepoint. Don't try to
// scan it, but rather leave it for the remark phase.
if (CMSPermGenPrecleaningEnabled &&
(!p->is_conc_safe() || !p->is_parsable())) {
// Signal precleaning to redirty the card since
// the klass pointer is already installed.
assert(size == 0, "Initial value");
@ -8071,9 +8075,13 @@ size_t SweepClosure::doLiveChunk(FreeChunk* fc) {
#ifdef DEBUG
if (oop(addr)->klass_or_null() != NULL &&
( !_collector->should_unload_classes()
|| oop(addr)->is_parsable())) {
|| (oop(addr)->is_parsable()) &&
oop(addr)->is_conc_safe())) {
// Ignore mark word because we are running concurrent with mutators
assert(oop(addr)->is_oop(true), "live block should be an oop");
// is_conc_safe is checked before performing this assertion
// because an object that is not is_conc_safe may yet have
// the return from size() correct.
assert(size ==
CompactibleFreeListSpace::adjustObjectSize(oop(addr)->size()),
"P-mark and computed size do not agree");
@ -8086,6 +8094,13 @@ size_t SweepClosure::doLiveChunk(FreeChunk* fc) {
(!_collector->should_unload_classes()
|| oop(addr)->is_parsable()),
"Should be an initialized object");
// Note that there are objects used during class redefinition
// (e.g., merge_cp in VM_RedefineClasses::merge_cp_and_rewrite()
// which are discarded with their is_conc_safe state still
// false. These object may be floating garbage so may be
// seen here. If they are floating garbage their size
// should be attainable from their klass. Do not that
// is_conc_safe() is true for oop(addr).
// Ignore mark word because we are running concurrent with mutators
assert(oop(addr)->is_oop(true), "live block should be an oop");
// Verify that the bit map has no bits marked between