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8222227: Shenandoah: Fix Traversal GC weak roots handling in final-traversal pause

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Reviewed-by: shade, zgu
This commit is contained in:
Roman Kennke 2019-04-09 23:36:43 +02:00
parent 321615029c
commit 990b45b149
2 changed files with 3 additions and 44 deletions
src/hotspot/share/gc/shenandoah
heuristics
shenandoahTraversalHeuristics.cpp
shenandoahTraversalGC.cpp

7
src/hotspot/share/gc/shenandoah/heuristics/shenandoahTraversalHeuristics.cpp

@ -41,13 +41,6 @@ ShenandoahTraversalHeuristics::ShenandoahTraversalHeuristics() : ShenandoahHeuri
FLAG_SET_DEFAULT(ShenandoahKeepAliveBarrier, false);
FLAG_SET_DEFAULT(ShenandoahAllowMixedAllocs, false);
SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahRefProcFrequency, 1);
// Adjust class unloading settings only if globally enabled.
if (ClassUnloadingWithConcurrentMark) {
SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUnloadClassesFrequency, 1);
}
SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent);
SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent);

40
src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp

@ -595,11 +595,10 @@ void ShenandoahTraversalGC::final_traversal_collection() {
}
if (!_heap->cancelled_gc()) {
fixup_roots();
if (_heap->unload_classes()) {
_heap->unload_classes_and_cleanup_tables(false);
}
fixup_roots();
}
if (!_heap->cancelled_gc()) {
@ -769,29 +768,6 @@ public:
void do_oop(oop* p) { do_oop_work(p); }
};
class ShenandoahTraversalWeakUpdateClosure : public OopClosure {
private:
template <class T>
inline void do_oop_work(T* p) {
// Cannot call maybe_update_with_forwarded, because on traversal-degen
// path the collection set is already dropped. Instead, do the unguarded store.
// TODO: This can be fixed after degen-traversal stops dropping cset.
T o = RawAccess<>::oop_load(p);
if (!CompressedOops::is_null(o)) {
oop obj = CompressedOops::decode_not_null(o);
obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
shenandoah_assert_marked(p, obj);
RawAccess<IS_NOT_NULL>::oop_store(p, obj);
}
}
public:
ShenandoahTraversalWeakUpdateClosure() {}
void do_oop(narrowOop* p) { do_oop_work(p); }
void do_oop(oop* p) { do_oop_work(p); }
};
class ShenandoahTraversalKeepAliveUpdateDegenClosure : public OopClosure {
private:
ShenandoahObjToScanQueue* _queue;
@ -1104,16 +1080,6 @@ void ShenandoahTraversalGC::weak_refs_work_doit() {
&pt);
}
{
ShenandoahGCPhase phase(phase_process);
ShenandoahTerminationTracker termination(ShenandoahPhaseTimings::weakrefs_termination);
// Process leftover weak oops (using parallel version)
ShenandoahTraversalWeakUpdateClosure cl;
WeakProcessor::weak_oops_do(workers, &is_alive, &cl, 1);
pt.print_all_references();
assert(task_queues()->is_empty() || _heap->cancelled_gc(), "Should be empty");
}
pt.print_all_references();
assert(task_queues()->is_empty() || _heap->cancelled_gc(), "Should be empty");
}