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8261356: Clean up enum G1Mark
Reviewed-by: sjohanss, tschatzl
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albertnetymk authored and kstefanj committed Feb 9, 2021
1 parent becee64 commit a00b13055a77790862e7a1c2e638a5265717981f
@@ -156,13 +156,7 @@ enum G1Barrier {
G1BarrierNoOptRoots // Do not collect optional roots.

enum G1Mark {

template <G1Barrier barrier, G1Mark do_mark_object>
template <G1Barrier barrier, bool should_mark>
class G1ParCopyClosure : public G1ParCopyHelper {
G1ParCopyClosure(G1CollectedHeap* g1h, G1ParScanThreadState* par_scan_state) :
@@ -215,9 +215,9 @@ void G1ParCopyHelper::trim_queue_partially() {

template <G1Barrier barrier, G1Mark do_mark_object>
template <G1Barrier barrier, bool should_mark>
template <class T>
void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* p) {
void G1ParCopyClosure<barrier, should_mark>::do_oop_work(T* p) {
T heap_oop = RawAccess<>::oop_load(p);

if (CompressedOops::is_null(heap_oop)) {
@@ -250,9 +250,10 @@ void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* p) {

// The object is not in collection set. If we're a root scanning
// closure during a concurrent start pause then attempt to mark the object.
if (do_mark_object == G1MarkFromRoot) {
// The object is not in the collection set. should_mark is true iff the
// current closure is applied on strong roots (and weak roots when class
// unloading is disabled) in a concurrent mark start pause.
if (should_mark) {
@@ -29,7 +29,7 @@

// Closures used for standard G1 evacuation.
class G1EvacuationClosures : public G1EvacuationRootClosures {
G1SharedClosures<G1MarkNone> _closures;
G1SharedClosures<false> _closures;

G1EvacuationClosures(G1CollectedHeap* g1h,
@@ -50,10 +50,10 @@ class G1EvacuationClosures : public G1EvacuationRootClosures {
// Closures used during concurrent start.
// The treatment of "weak" roots is selectable through the template parameter,
// this is usually used to control unloading of classes and interned strings.
template <G1Mark MarkWeak>
template <bool should_mark_weak>
class G1ConcurrentStartMarkClosures : public G1EvacuationRootClosures {
G1SharedClosures<G1MarkFromRoot> _strong;
G1SharedClosures<MarkWeak> _weak;
G1SharedClosures<true> _strong;
G1SharedClosures<should_mark_weak> _weak;

G1ConcurrentStartMarkClosures(G1CollectedHeap* g1h,
@@ -75,9 +75,9 @@ G1EvacuationRootClosures* G1EvacuationRootClosures::create_root_closures(G1ParSc
G1EvacuationRootClosures* res = NULL;
if (g1h->collector_state()->in_concurrent_start_gc()) {
if (ClassUnloadingWithConcurrentMark) {
res = new G1ConcurrentStartMarkClosures<G1MarkPromotedFromRoot>(g1h, pss);
res = new G1ConcurrentStartMarkClosures<false>(g1h, pss);
} else {
res = new G1ConcurrentStartMarkClosures<G1MarkFromRoot>(g1h, pss);
res = new G1ConcurrentStartMarkClosures<true>(g1h, pss);
} else {
res = new G1EvacuationClosures(g1h, pss, g1h->collector_state()->in_young_only_phase());
@@ -30,24 +30,19 @@ class G1CollectedHeap;
class G1ParScanThreadState;

// Simple holder object for a complete set of closures used by the G1 evacuation code.
template <G1Mark Mark>
template <bool should_mark>
class G1SharedClosures {
static bool needs_strong_processing() {
// Request strong code root processing when G1MarkFromRoot is passed in during
// concurrent start.
return Mark == G1MarkFromRoot;
G1ParCopyClosure<G1BarrierNone, Mark> _oops;
G1ParCopyClosure<G1BarrierCLD, Mark> _oops_in_cld;
G1ParCopyClosure<G1BarrierNone, should_mark> _oops;
G1ParCopyClosure<G1BarrierCLD, should_mark> _oops_in_cld;
// We do not need (and actually should not) collect oops from nmethods into the
// optional collection set as we already automatically collect the corresponding
// nmethods in the region's strong code roots set. So set G1BarrierNoOptRoots in
// this closure.
// If these were present there would be opportunity for multiple threads to try
// to change this oop* at the same time. Since embedded oops are not necessarily
// word-aligned, this could lead to word tearing during update and crashes.
G1ParCopyClosure<G1BarrierNoOptRoots, Mark> _oops_in_nmethod;
G1ParCopyClosure<G1BarrierNoOptRoots, should_mark> _oops_in_nmethod;

G1CLDScanClosure _clds;
G1CodeBlobClosure _codeblobs;
@@ -57,5 +52,5 @@ class G1SharedClosures {
_oops_in_cld(g1h, pss),
_oops_in_nmethod(g1h, pss),
_clds(&_oops_in_cld, process_only_dirty),
_codeblobs(pss->worker_id(), &_oops_in_nmethod, needs_strong_processing()) {}
_codeblobs(pss->worker_id(), &_oops_in_nmethod, should_mark) {}

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