8273614: Shenandoah: intermittent timeout with ConcurrentGCBreakpoint tests

Reviewed-by: shade

Author: zhengyu123

src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp

@@ -50,24 +50,37 @@
 
 // Breakpoint support
 class ShenandoahBreakpointGCScope : public StackObj {
+private:
+  const GCCause::Cause _cause;
 public:
-  ShenandoahBreakpointGCScope() {
-    ShenandoahBreakpoint::at_before_gc();
+  ShenandoahBreakpointGCScope(GCCause::Cause cause) : _cause(cause) {
+    if (cause == GCCause::_wb_breakpoint) {
+      ShenandoahBreakpoint::start_gc();
+      ShenandoahBreakpoint::at_before_gc();
+    }
   }
 
   ~ShenandoahBreakpointGCScope() {
-    ShenandoahBreakpoint::at_after_gc();
+    if (_cause == GCCause::_wb_breakpoint) {
+      ShenandoahBreakpoint::at_after_gc();
+    }
   }
 };
 
 class ShenandoahBreakpointMarkScope : public StackObj {
+private:
+  const GCCause::Cause _cause;
 public:
-  ShenandoahBreakpointMarkScope() {
-    ShenandoahBreakpoint::at_after_marking_started();
+  ShenandoahBreakpointMarkScope(GCCause::Cause cause) : _cause(cause) {
+    if (_cause == GCCause::_wb_breakpoint) {
+      ShenandoahBreakpoint::at_after_marking_started();
+    }
   }
 
   ~ShenandoahBreakpointMarkScope() {
-    ShenandoahBreakpoint::at_before_marking_completed();
+    if (_cause == GCCause::_wb_breakpoint) {
+      ShenandoahBreakpoint::at_before_marking_completed();
+    }
   }
 };
 
@@ -86,10 +99,7 @@ void ShenandoahConcurrentGC::cancel() {
 
 bool ShenandoahConcurrentGC::collect(GCCause::Cause cause) {
   ShenandoahHeap* const heap = ShenandoahHeap::heap();
-  if (cause == GCCause::_wb_breakpoint) {
-    ShenandoahBreakpoint::start_gc();
-  }
-  ShenandoahBreakpointGCScope breakpoint_gc_scope;
+  ShenandoahBreakpointGCScope breakpoint_gc_scope(cause);
 
   // Reset for upcoming marking
   entry_reset();
@@ -98,7 +108,7 @@ bool ShenandoahConcurrentGC::collect(GCCause::Cause cause) {
   vmop_entry_init_mark();
 
   {
-    ShenandoahBreakpointMarkScope breakpoint_mark_scope;
+    ShenandoahBreakpointMarkScope breakpoint_mark_scope(cause);
     // Concurrent mark roots
     entry_mark_roots();
     if (check_cancellation_and_abort(ShenandoahDegenPoint::_degenerated_outside_cycle)) return false;
@@ -657,7 +667,9 @@ void ShenandoahConcurrentGC::op_weak_refs() {
   assert(heap->is_concurrent_weak_root_in_progress(), "Only during this phase");
   // Concurrent weak refs processing
   ShenandoahGCWorkerPhase worker_phase(ShenandoahPhaseTimings::conc_weak_refs);
-  ShenandoahBreakpoint::at_after_reference_processing_started();
+  if (heap->gc_cause() == GCCause::_wb_breakpoint) {
+    ShenandoahBreakpoint::at_after_reference_processing_started();
+  }
   heap->ref_processor()->process_references(ShenandoahPhaseTimings::conc_weak_refs, heap->workers(), true /* concurrent */);
 }