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6798898: CMS: bugs related to class unloading

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Override should_remember_klasses() and remember_klass() as needed.

Reviewed-by: ysr, jcoomes
This commit is contained in:
Jon Masamitsu 2009-08-24 10:36:31 -07:00
parent ead860c069
commit 20a43bad21
8 changed files with 238 additions and 105 deletions
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139
hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp
View file

@ -2276,7 +2276,7 @@ void CMSCollector::collect_in_background(bool clear_all_soft_refs) {
VM_CMS_Final_Remark final_remark_op(this);
VMThread::execute(&final_remark_op);
}
}
assert(_foregroundGCShouldWait, "block post-condition");
break;
case Sweeping:
@ -3499,6 +3499,7 @@ void CMSCollector::checkpointRootsInitialWork(bool asynch) {
ref_processor()->set_enqueuing_is_done(false);
{
// This is not needed. DEBUG_ONLY(RememberKlassesChecker imx(true);)
COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact;)
gch->rem_set()->prepare_for_younger_refs_iterate(false); // Not parallel.
gch->gen_process_strong_roots(_cmsGen->level(),
@ -3623,6 +3624,8 @@ bool CMSCollector::markFromRootsWork(bool asynch) {
verify_overflow_empty();
assert(_revisitStack.isEmpty(), "tabula rasa");
DEBUG_ONLY(RememberKlassesChecker cmx(CMSClassUnloadingEnabled);)
bool result = false;
if (CMSConcurrentMTEnabled && ParallelCMSThreads > 0) {
result = do_marking_mt(asynch);
@ -3958,24 +3961,24 @@ void CMSConcMarkingTask::do_scan_and_mark(int i, CompactibleFreeListSpace* sp) {
pst->all_tasks_completed();
}
class Par_ConcMarkingClosure: public OopClosure {
class Par_ConcMarkingClosure: public Par_KlassRememberingOopClosure {
private:
CMSCollector* _collector;
MemRegion _span;
CMSBitMap* _bit_map;
CMSMarkStack* _overflow_stack;
CMSMarkStack* _revisit_stack; // XXXXXX Check proper use
OopTaskQueue* _work_queue;
protected:
DO_OOP_WORK_DEFN
public:
Par_ConcMarkingClosure(CMSCollector* collector, OopTaskQueue* work_queue,
CMSBitMap* bit_map, CMSMarkStack* overflow_stack):
_collector(collector),
CMSBitMap* bit_map, CMSMarkStack* overflow_stack,
CMSMarkStack* revisit_stack):
Par_KlassRememberingOopClosure(collector, NULL, revisit_stack),
_span(_collector->_span),
_work_queue(work_queue),
_bit_map(bit_map),
_overflow_stack(overflow_stack) { } // need to initialize revisit stack etc.
_overflow_stack(overflow_stack)
{ }
virtual void do_oop(oop* p);
virtual void do_oop(narrowOop* p);
void trim_queue(size_t max);
@ -4063,8 +4066,9 @@ void CMSConcMarkingTask::do_work_steal(int i) {
oop obj_to_scan;
CMSBitMap* bm = &(_collector->_markBitMap);
CMSMarkStack* ovflw = &(_collector->_markStack);
CMSMarkStack* revisit = &(_collector->_revisitStack);
int* seed = _collector->hash_seed(i);
Par_ConcMarkingClosure cl(_collector, work_q, bm, ovflw);
Par_ConcMarkingClosure cl(_collector, work_q, bm, ovflw, revisit);
while (true) {
cl.trim_queue(0);
assert(work_q->size() == 0, "Should have been emptied above");
@ -4089,6 +4093,7 @@ void CMSConcMarkingTask::coordinator_yield() {
assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
"CMS thread should hold CMS token");
DEBUG_ONLY(RememberKlassesChecker mux(false);)
// First give up the locks, then yield, then re-lock
// We should probably use a constructor/destructor idiom to
// do this unlock/lock or modify the MutexUnlocker class to
@ -4165,6 +4170,8 @@ bool CMSCollector::do_marking_mt(bool asynch) {
// multi-threaded marking phase.
ReferenceProcessorMTMutator mt(ref_processor(), num_workers > 1);
DEBUG_ONLY(RememberKlassesChecker cmx(CMSClassUnloadingEnabled);)
conc_workers()->start_task(&tsk);
while (tsk.yielded()) {
tsk.coordinator_yield();
@ -4404,7 +4411,8 @@ size_t CMSCollector::preclean_work(bool clean_refs, bool clean_survivor) {
CMSPrecleanRefsYieldClosure yield_cl(this);
assert(rp->span().equals(_span), "Spans should be equal");
CMSKeepAliveClosure keep_alive(this, _span, &_markBitMap,
&_markStack, true /* preclean */);
&_markStack, &_revisitStack,
true /* preclean */);
CMSDrainMarkingStackClosure complete_trace(this,
_span, &_markBitMap, &_markStack,
&keep_alive, true /* preclean */);
@ -4424,6 +4432,7 @@ size_t CMSCollector::preclean_work(bool clean_refs, bool clean_survivor) {
bitMapLock());
startTimer();
sample_eden();
// The following will yield to allow foreground
// collection to proceed promptly. XXX YSR:
// The code in this method may need further
@ -4453,6 +4462,7 @@ size_t CMSCollector::preclean_work(bool clean_refs, bool clean_survivor) {
SurvivorSpacePrecleanClosure
sss_cl(this, _span, &_markBitMap, &_markStack,
&pam_cl, before_count, CMSYield);
DEBUG_ONLY(RememberKlassesChecker mx(CMSClassUnloadingEnabled);)
dng->from()->object_iterate_careful(&sss_cl);
dng->to()->object_iterate_careful(&sss_cl);
}
@ -4554,6 +4564,13 @@ size_t CMSCollector::preclean_mod_union_table(
verify_work_stacks_empty();
verify_overflow_empty();
// Turn off checking for this method but turn it back on
// selectively. There are yield points in this method
// but it is difficult to turn the checking off just around
// the yield points. It is simpler to selectively turn
// it on.
DEBUG_ONLY(RememberKlassesChecker mux(false);)
// strategy: starting with the first card, accumulate contiguous
// ranges of dirty cards; clear these cards, then scan the region
// covered by these cards.
@ -4582,6 +4599,7 @@ size_t CMSCollector::preclean_mod_union_table(
MemRegion dirtyRegion;
{
stopTimer();
// Potential yield point
CMSTokenSync ts(true);
startTimer();
sample_eden();
@ -4607,6 +4625,7 @@ size_t CMSCollector::preclean_mod_union_table(
assert(numDirtyCards > 0, "consistency check");
HeapWord* stop_point = NULL;
stopTimer();
// Potential yield point
CMSTokenSyncWithLocks ts(true, gen->freelistLock(),
bitMapLock());
startTimer();
@ -4614,6 +4633,7 @@ size_t CMSCollector::preclean_mod_union_table(
verify_work_stacks_empty();
verify_overflow_empty();
sample_eden();
DEBUG_ONLY(RememberKlassesChecker mx(CMSClassUnloadingEnabled);)
stop_point =
gen->cmsSpace()->object_iterate_careful_m(dirtyRegion, cl);
}
@ -4701,6 +4721,7 @@ size_t CMSCollector::preclean_card_table(ConcurrentMarkSweepGeneration* gen,
sample_eden();
verify_work_stacks_empty();
verify_overflow_empty();
DEBUG_ONLY(RememberKlassesChecker mx(CMSClassUnloadingEnabled);)
HeapWord* stop_point =
gen->cmsSpace()->object_iterate_careful_m(dirtyRegion, cl);
if (stop_point != NULL) {
@ -4800,6 +4821,7 @@ void CMSCollector::checkpointRootsFinalWork(bool asynch,
assert(haveFreelistLocks(), "must have free list locks");
assert_lock_strong(bitMapLock());
DEBUG_ONLY(RememberKlassesChecker fmx(CMSClassUnloadingEnabled);)
if (!init_mark_was_synchronous) {
// We might assume that we need not fill TLAB's when
// CMSScavengeBeforeRemark is set, because we may have just done
@ -4903,6 +4925,9 @@ void CMSCollector::checkpointRootsFinalWork(bool asynch,
_markStack._hit_limit = 0;
_markStack._failed_double = 0;
// Check that all the klasses have been checked
assert(_revisitStack.isEmpty(), "Not all klasses revisited");
if ((VerifyAfterGC || VerifyDuringGC) &&
GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
verify_after_remark();
@ -5574,9 +5599,13 @@ public:
void CMSRefProcTaskProxy::work(int i) {
assert(_collector->_span.equals(_span), "Inconsistency in _span");
CMSParKeepAliveClosure par_keep_alive(_collector, _span,
_mark_bit_map, work_queue(i));
_mark_bit_map,
&_collector->_revisitStack,
work_queue(i));
CMSParDrainMarkingStackClosure par_drain_stack(_collector, _span,
_mark_bit_map, work_queue(i));
_mark_bit_map,
&_collector->_revisitStack,
work_queue(i));
CMSIsAliveClosure is_alive_closure(_span, _mark_bit_map);
_task.work(i, is_alive_closure, par_keep_alive, par_drain_stack);
if (_task.marks_oops_alive()) {
@ -5604,12 +5633,13 @@ public:
};
CMSParKeepAliveClosure::CMSParKeepAliveClosure(CMSCollector* collector,
MemRegion span, CMSBitMap* bit_map, OopTaskQueue* work_queue):
_collector(collector),
MemRegion span, CMSBitMap* bit_map, CMSMarkStack* revisit_stack,
OopTaskQueue* work_queue):
Par_KlassRememberingOopClosure(collector, NULL, revisit_stack),
_span(span),
_bit_map(bit_map),
_work_queue(work_queue),
_mark_and_push(collector, span, bit_map, work_queue),
_mark_and_push(collector, span, bit_map, revisit_stack, work_queue),
_low_water_mark(MIN2((uint)(work_queue->max_elems()/4),
(uint)(CMSWorkQueueDrainThreshold * ParallelGCThreads)))
{ }
@ -5696,7 +5726,8 @@ void CMSCollector::refProcessingWork(bool asynch, bool clear_all_soft_refs) {
verify_work_stacks_empty();
CMSKeepAliveClosure cmsKeepAliveClosure(this, _span, &_markBitMap,
&_markStack, false /* !preclean */);
&_markStack, &_revisitStack,
false /* !preclean */);
CMSDrainMarkingStackClosure cmsDrainMarkingStackClosure(this,
_span, &_markBitMap, &_markStack,
&cmsKeepAliveClosure, false /* !preclean */);
@ -6531,6 +6562,7 @@ void MarkRefsIntoAndScanClosure::do_yield_work() {
assert_lock_strong(_freelistLock);
assert_lock_strong(_bit_map->lock());
// relinquish the free_list_lock and bitMaplock()
DEBUG_ONLY(RememberKlassesChecker mux(false);)
_bit_map->lock()->unlock();
_freelistLock->unlock();
ConcurrentMarkSweepThread::desynchronize(true);
@ -6703,6 +6735,7 @@ void ScanMarkedObjectsAgainCarefullyClosure::do_yield_work() {
"CMS thread should hold CMS token");
assert_lock_strong(_freelistLock);
assert_lock_strong(_bitMap->lock());
DEBUG_ONLY(RememberKlassesChecker mux(false);)
// relinquish the free_list_lock and bitMaplock()
_bitMap->lock()->unlock();
_freelistLock->unlock();
@ -6779,6 +6812,7 @@ void SurvivorSpacePrecleanClosure::do_yield_work() {
assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
"CMS thread should hold CMS token");
assert_lock_strong(_bit_map->lock());
DEBUG_ONLY(RememberKlassesChecker smx(false);)
// Relinquish the bit map lock
_bit_map->lock()->unlock();
ConcurrentMarkSweepThread::desynchronize(true);
@ -6941,6 +6975,7 @@ void MarkFromRootsClosure::do_yield_work() {
assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
"CMS thread should hold CMS token");
assert_lock_strong(_bitMap->lock());
DEBUG_ONLY(RememberKlassesChecker mux(false);)
_bitMap->lock()->unlock();
ConcurrentMarkSweepThread::desynchronize(true);
ConcurrentMarkSweepThread::acknowledge_yield_request();
@ -7295,15 +7330,12 @@ PushOrMarkClosure::PushOrMarkClosure(CMSCollector* collector,
CMSBitMap* bitMap, CMSMarkStack* markStack,
CMSMarkStack* revisitStack,
HeapWord* finger, MarkFromRootsClosure* parent) :
OopClosure(collector->ref_processor()),
_collector(collector),
KlassRememberingOopClosure(collector, collector->ref_processor(), revisitStack),
_span(span),
_bitMap(bitMap),
_markStack(markStack),
_revisitStack(revisitStack),
_finger(finger),
_parent(parent),
_should_remember_klasses(collector->should_unload_classes())
_parent(parent)
{ }
Par_PushOrMarkClosure::Par_PushOrMarkClosure(CMSCollector* collector,
@ -7315,18 +7347,17 @@ Par_PushOrMarkClosure::Par_PushOrMarkClosure(CMSCollector* collector,
HeapWord* finger,
HeapWord** global_finger_addr,
Par_MarkFromRootsClosure* parent) :
OopClosure(collector->ref_processor()),
_collector(collector),
Par_KlassRememberingOopClosure(collector,
collector->ref_processor(),
revisit_stack),
_whole_span(collector->_span),
_span(span),
_bit_map(bit_map),
_work_queue(work_queue),
_overflow_stack(overflow_stack),
_revisit_stack(revisit_stack),
_finger(finger),
_global_finger_addr(global_finger_addr),
_parent(parent),
_should_remember_klasses(collector->should_unload_classes())
_parent(parent)
{ }
// Assumes thread-safe access by callers, who are
@ -7456,6 +7487,14 @@ void Par_PushOrMarkClosure::do_oop(oop obj) {
void Par_PushOrMarkClosure::do_oop(oop* p) { Par_PushOrMarkClosure::do_oop_work(p); }
void Par_PushOrMarkClosure::do_oop(narrowOop* p) { Par_PushOrMarkClosure::do_oop_work(p); }
KlassRememberingOopClosure::KlassRememberingOopClosure(CMSCollector* collector,
ReferenceProcessor* rp,
CMSMarkStack* revisit_stack) :
OopClosure(rp),
_collector(collector),
_revisit_stack(revisit_stack),
_should_remember_klasses(collector->should_unload_classes()) {}
PushAndMarkClosure::PushAndMarkClosure(CMSCollector* collector,
MemRegion span,
ReferenceProcessor* rp,
@ -7464,15 +7503,12 @@ PushAndMarkClosure::PushAndMarkClosure(CMSCollector* collector,
CMSMarkStack* mark_stack,
CMSMarkStack* revisit_stack,
bool concurrent_precleaning):
OopClosure(rp),
_collector(collector),
KlassRememberingOopClosure(collector, rp, revisit_stack),
_span(span),
_bit_map(bit_map),
_mod_union_table(mod_union_table),
_mark_stack(mark_stack),
_revisit_stack(revisit_stack),
_concurrent_precleaning(concurrent_precleaning),
_should_remember_klasses(collector->should_unload_classes())
_concurrent_precleaning(concurrent_precleaning)
{
assert(_ref_processor != NULL, "_ref_processor shouldn't be NULL");
}
@ -7540,13 +7576,10 @@ Par_PushAndMarkClosure::Par_PushAndMarkClosure(CMSCollector* collector,
CMSBitMap* bit_map,
OopTaskQueue* work_queue,
CMSMarkStack* revisit_stack):
OopClosure(rp),
_collector(collector),
Par_KlassRememberingOopClosure(collector, rp, revisit_stack),
_span(span),
_bit_map(bit_map),
_work_queue(work_queue),
_revisit_stack(revisit_stack),
_should_remember_klasses(collector->should_unload_classes())
_work_queue(work_queue)
{
assert(_ref_processor != NULL, "_ref_processor shouldn't be NULL");
}
@ -7599,19 +7632,8 @@ void Par_PushAndMarkClosure::do_oop(oop obj) {
void Par_PushAndMarkClosure::do_oop(oop* p) { Par_PushAndMarkClosure::do_oop_work(p); }
void Par_PushAndMarkClosure::do_oop(narrowOop* p) { Par_PushAndMarkClosure::do_oop_work(p); }
void PushAndMarkClosure::remember_klass(Klass* k) {
if (!_revisit_stack->push(oop(k))) {
fatal("Revisit stack overflowed in PushAndMarkClosure");
}
}
void Par_PushAndMarkClosure::remember_klass(Klass* k) {
if (!_revisit_stack->par_push(oop(k))) {
fatal("Revist stack overflowed in Par_PushAndMarkClosure");
}
}
void CMSPrecleanRefsYieldClosure::do_yield_work() {
DEBUG_ONLY(RememberKlassesChecker mux(false);)
Mutex* bml = _collector->bitMapLock();
assert_lock_strong(bml);
assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
@ -8302,6 +8324,19 @@ bool CMSIsAliveClosure::do_object_b(oop obj) {
(!_span.contains(addr) || _bit_map->isMarked(addr));
}
CMSKeepAliveClosure::CMSKeepAliveClosure( CMSCollector* collector,
MemRegion span,
CMSBitMap* bit_map, CMSMarkStack* mark_stack,
CMSMarkStack* revisit_stack, bool cpc):
KlassRememberingOopClosure(collector, NULL, revisit_stack),
_span(span),
_bit_map(bit_map),
_mark_stack(mark_stack),
_concurrent_precleaning(cpc) {
assert(!_span.is_empty(), "Empty span could spell trouble");
}
// CMSKeepAliveClosure: the serial version
void CMSKeepAliveClosure::do_oop(oop obj) {
HeapWord* addr = (HeapWord*)obj;
@ -8385,6 +8420,16 @@ void CMSParKeepAliveClosure::trim_queue(uint max) {
}
}
CMSInnerParMarkAndPushClosure::CMSInnerParMarkAndPushClosure(
CMSCollector* collector,
MemRegion span, CMSBitMap* bit_map,
CMSMarkStack* revisit_stack,
OopTaskQueue* work_queue):
Par_KlassRememberingOopClosure(collector, NULL, revisit_stack),
_span(span),
_bit_map(bit_map),
_work_queue(work_queue) { }
void CMSInnerParMarkAndPushClosure::do_oop(oop obj) {
HeapWord* addr = (HeapWord*)obj;
if (_span.contains(addr) &&