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8322503: Shenandoah: Clarify gc state usage #365

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8322503: Shenandoah: Clarify gc state usage #365

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14 changes: 7 additions & 7 deletions src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1682,7 +1682,7 @@ void ShenandoahHeap::prepare_update_heap_references(bool concurrent) {
_update_refs_iterator.reset();
}

void ShenandoahHeap::set_gc_state_all_threads() {
void ShenandoahHeap::propagate_gc_state_to_java_threads() {
assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at Shenandoah safepoint");
if (_gc_state_changed) {
_gc_state_changed = false;
Expand All @@ -1693,21 +1693,21 @@ void ShenandoahHeap::set_gc_state_all_threads() {
}
}

void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
void ShenandoahHeap::set_gc_state(uint mask, bool value) {
assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at Shenandoah safepoint");
_gc_state.set_cond(mask, value);
_gc_state_changed = true;
}

void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
assert(!has_forwarded_objects(), "Not expected before/after mark phase");
set_gc_state_mask(MARKING, in_progress);
set_gc_state(MARKING, in_progress);
ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
}

void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
set_gc_state_mask(EVACUATION, in_progress);
set_gc_state(EVACUATION, in_progress);
}

void ShenandoahHeap::set_concurrent_strong_root_in_progress(bool in_progress) {
Expand All @@ -1719,7 +1719,7 @@ void ShenandoahHeap::set_concurrent_strong_root_in_progress(bool in_progress) {
}

void ShenandoahHeap::set_concurrent_weak_root_in_progress(bool cond) {
set_gc_state_mask(WEAK_ROOTS, cond);
set_gc_state(WEAK_ROOTS, cond);
}

GCTracer* ShenandoahHeap::tracer() {
Expand Down Expand Up @@ -1838,7 +1838,7 @@ void ShenandoahHeap::parallel_cleaning(bool full_gc) {
}

void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
set_gc_state_mask(HAS_FORWARDED, cond);
set_gc_state(HAS_FORWARDED, cond);
}

void ShenandoahHeap::set_unload_classes(bool uc) {
Expand Down Expand Up @@ -1877,7 +1877,7 @@ void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
}

void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
set_gc_state_mask(UPDATEREFS, in_progress);
set_gc_state(UPDATEREFS, in_progress);
}

void ShenandoahHeap::register_nmethod(nmethod* nm) {
Expand Down
13 changes: 10 additions & 3 deletions src/hotspot/share/gc/shenandoah/shenandoahHeap.hpp
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Expand Up @@ -289,12 +289,19 @@ class ShenandoahHeap : public CollectedHeap {
ShenandoahSharedFlag _progress_last_gc;
ShenandoahSharedFlag _concurrent_strong_root_in_progress;

void set_gc_state_mask(uint mask, bool value);
// This updates the singlular, global gc state. This must happen on a safepoint.
void set_gc_state(uint mask, bool value);

public:
char gc_state() const;
void set_gc_state_all_threads();
bool has_gc_state_changed() { return _gc_state_changed; }

// This copies the global gc state into a thread local variable for java threads.
// It is primarily intended to support quick access at barriers.
void propagate_gc_state_to_java_threads();

// This is public to support assertions that the state hasn't been changed off of
// a safepoint and that any changes were propagated to java threads after the safepoint.
bool has_gc_state_changed() const { return _gc_state_changed; }

void set_concurrent_mark_in_progress(bool in_progress);
void set_evacuation_in_progress(bool in_progress);
Expand Down
1 change: 1 addition & 0 deletions src/hotspot/share/gc/shenandoah/shenandoahThreadLocalData.hpp
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Expand Up @@ -89,6 +89,7 @@ class ShenandoahThreadLocalData {
}

static char gc_state(Thread* thread) {
assert(thread->is_Java_thread(), "GC state is only synchronized to java threads");
return data(thread)->_gc_state;
}

Expand Down
14 changes: 7 additions & 7 deletions src/hotspot/share/gc/shenandoah/shenandoahVMOperations.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -62,41 +62,41 @@ void VM_ShenandoahReferenceOperation::doit_epilogue() {
void VM_ShenandoahInitMark::doit() {
ShenandoahGCPauseMark mark(_gc_id, "Init Mark", SvcGCMarker::CONCURRENT);
_gc->entry_init_mark();
ShenandoahHeap::heap()->set_gc_state_all_threads();
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
}

void VM_ShenandoahFinalMarkStartEvac::doit() {
ShenandoahGCPauseMark mark(_gc_id, "Final Mark", SvcGCMarker::CONCURRENT);
_gc->entry_final_mark();
ShenandoahHeap::heap()->set_gc_state_all_threads();
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
}

void VM_ShenandoahFullGC::doit() {
ShenandoahGCPauseMark mark(_gc_id, "Full GC", SvcGCMarker::FULL);
_full_gc->entry_full(_gc_cause);
ShenandoahHeap::heap()->set_gc_state_all_threads();
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
}

void VM_ShenandoahDegeneratedGC::doit() {
ShenandoahGCPauseMark mark(_gc_id, "Degenerated GC", SvcGCMarker::CONCURRENT);
_gc->entry_degenerated();
ShenandoahHeap::heap()->set_gc_state_all_threads();
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
}

void VM_ShenandoahInitUpdateRefs::doit() {
ShenandoahGCPauseMark mark(_gc_id, "Init Update Refs", SvcGCMarker::CONCURRENT);
_gc->entry_init_updaterefs();
ShenandoahHeap::heap()->set_gc_state_all_threads();
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
}

void VM_ShenandoahFinalUpdateRefs::doit() {
ShenandoahGCPauseMark mark(_gc_id, "Final Update Refs", SvcGCMarker::CONCURRENT);
_gc->entry_final_updaterefs();
ShenandoahHeap::heap()->set_gc_state_all_threads();
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
}

void VM_ShenandoahFinalRoots::doit() {
ShenandoahGCPauseMark mark(_gc_id, "Final Roots", SvcGCMarker::CONCURRENT);
_gc->entry_final_roots();
ShenandoahHeap::heap()->set_gc_state_all_threads();
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
}
2 changes: 1 addition & 1 deletion src/hotspot/share/gc/shenandoah/shenandoahVerifier.cpp
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Expand Up @@ -620,7 +620,7 @@ void ShenandoahVerifier::verify_at_safepoint(const char *label,
guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");

ShenandoahHeap::heap()->set_gc_state_all_threads();
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();

// Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
Expand Down