8386512: Shenandoah: Add a diagnostic option to facilitate testing pinned regions

Reviewed-by: kdnilsen, wkemper

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

@@ -109,6 +109,7 @@ void ShenandoahConcurrentGC::entry_concurrent_update_refs_prepare(ShenandoahHeap
   ShenandoahConcurrentPhase gc_phase(msg, ShenandoahPhaseTimings::conc_update_refs_prepare);
   EventMark em("%s", msg);
 
+  heap->try_inject_pin();
   // Evacuation is complete, retire gc labs and change gc state
   heap->concurrent_prepare_for_update_refs();
 }
@@ -125,6 +126,7 @@ void ShenandoahConcurrentGC::entry_update_card_table() {
                               ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
                               "concurrent update cards");
 
+  heap->try_inject_pin();
   // Heap needs to be parsable here.
   // Also, parallel heap region iterate must have a phase set.
   assert(ShenandoahTimingsTracker::is_current_phase_valid(), "Current phase must be set");
@@ -301,6 +303,7 @@ void ShenandoahConcurrentGC::entry_complete_abbreviated_cycle() {
                               ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
                               msg);
 
+  heap->try_inject_pin();
   // We chose not to evacuate because we found sufficient immediate garbage.
   // However, there may still be regions to promote in place, so do that now.
   if (heap->old_generation()->has_in_place_promotions()) {
@@ -335,6 +338,7 @@ void ShenandoahConcurrentGC::vmop_entry_final_mark() {
   heap->try_inject_alloc_failure();
   VM_ShenandoahFinalMarkStartEvac op(this);
   VMThread::execute(&op); // jump to entry_final_mark under safepoint
+  heap->try_inject_pin();
 }
 
 void ShenandoahConcurrentGC::vmop_entry_init_update_refs() {
@@ -343,6 +347,7 @@ void ShenandoahConcurrentGC::vmop_entry_init_update_refs() {
   ShenandoahTimingsTracker timing(ShenandoahPhaseTimings::init_update_refs_gross);
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   VM_ShenandoahInitUpdateRefs op(this);
   VMThread::execute(&op);
 }
@@ -353,6 +358,7 @@ void ShenandoahConcurrentGC::vmop_entry_final_update_refs() {
   ShenandoahTimingsTracker timing(ShenandoahPhaseTimings::final_update_refs_gross);
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   VM_ShenandoahFinalUpdateRefs op(this);
   VMThread::execute(&op);
 }
@@ -364,6 +370,7 @@ void ShenandoahConcurrentGC::vmop_entry_final_verify() {
 
   // This phase does not use workers, no need for setup
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   VM_ShenandoahFinalVerify op(this);
   VMThread::execute(&op);
 }
@@ -423,6 +430,7 @@ void ShenandoahConcurrentGC::entry_final_verify() {
 
 void ShenandoahConcurrentGC::entry_reset() {
   ShenandoahHeap* const heap = ShenandoahHeap::heap();
+  heap->release_injected_pins();
   heap->try_inject_alloc_failure();
 
   TraceCollectorStats tcs(heap->monitoring_support()->concurrent_collection_counters());
@@ -483,6 +491,7 @@ void ShenandoahConcurrentGC::entry_mark() {
 
   heap->try_inject_alloc_failure();
   op_mark();
+  heap->try_inject_pin();
 }
 
 void ShenandoahConcurrentGC::entry_thread_roots() {
@@ -496,6 +505,7 @@ void ShenandoahConcurrentGC::entry_thread_roots() {
                               msg);
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_thread_roots();
 }
 
@@ -510,6 +520,7 @@ void ShenandoahConcurrentGC::entry_weak_refs() {
                               "concurrent weak references");
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_weak_refs();
 }
 
@@ -525,6 +536,7 @@ void ShenandoahConcurrentGC::entry_weak_roots() {
                               "concurrent weak root");
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_weak_roots();
 }
 
@@ -540,6 +552,7 @@ void ShenandoahConcurrentGC::entry_class_unloading() {
                               "concurrent class unloading");
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_class_unloading();
 }
 
@@ -557,6 +570,7 @@ void ShenandoahConcurrentGC::entry_strong_roots() {
                               "concurrent strong root");
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_strong_roots();
 }
 
@@ -569,6 +583,7 @@ void ShenandoahConcurrentGC::entry_cleanup_early() {
 
   // This phase does not use workers, no need for setup
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_cleanup_early();
   if (!heap->is_evacuation_in_progress()) {
     // This is an abbreviated cycle.  Rebuild the freeset in order to establish reserves for the next GC cycle.  Doing
@@ -591,6 +606,7 @@ void ShenandoahConcurrentGC::entry_evacuate() {
                               "concurrent evacuation");
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_evacuate();
 }
 
@@ -604,6 +620,7 @@ void ShenandoahConcurrentGC::entry_update_thread_roots() {
 
   // No workers used in this phase, no setup required
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_update_thread_roots();
 }
 
@@ -619,6 +636,7 @@ void ShenandoahConcurrentGC::entry_update_refs() {
                               "concurrent reference update");
 
   heap->try_inject_alloc_failure();
+  heap->try_inject_pin();
   op_update_refs();
 }
 

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

@@ -91,6 +91,7 @@ void ShenandoahDegenGC::entry_degenerated() {
 
 void ShenandoahDegenGC::op_degenerated() {
   ShenandoahHeap* const heap = ShenandoahHeap::heap();
+  heap->release_injected_pins();
   // Degenerated GC is STW, but it can also fail. Current mechanics communicates
   // GC failure via cancelled_concgc() flag. So, if we detect the failure after
   // some phase, we have to upgrade the Degenerate GC to Full GC.

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

@@ -136,6 +136,7 @@ void ShenandoahFullGC::op_full(GCCause::Cause cause) {
 
 void ShenandoahFullGC::do_it(GCCause::Cause gc_cause) {
   ShenandoahHeap* heap = ShenandoahHeap::heap();
+  heap->release_injected_pins();
 
   // A full GC may be entered directly, or as an upgrade from a failed
   // degenerated GC. In the latter case, self-forwarded objects may be

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

@@ -595,7 +595,8 @@ ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
   _aux_bitmap_region_special(false),
   _liveness_cache(nullptr),
   _collection_set(nullptr),
-  _evac_tracker(new ShenandoahEvacuationTracker())
+  _evac_tracker(new ShenandoahEvacuationTracker()),
+  _injected_pin_count(0)
 {
   // Initialize GC mode early, many subsequent initialization procedures depend on it
   initialize_mode();
@@ -2752,6 +2753,39 @@ bool ShenandoahHeap::should_inject_alloc_failure() {
   return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
 }
 
+void ShenandoahHeap::try_inject_pin() {
+  assert(!ShenandoahSafepoint::is_at_shenandoah_safepoint(), "try_inject_pin() must be called outside a safepoint.");
+  assert(active_generation() != nullptr, "Active generation must be set before we inject pins.");
+  assert(is_concurrent_mark_in_progress() || active_generation()->is_mark_complete(),
+         "try_inject_pin() requires marking is in progress or has completed.");
+  if (ShenandoahPinRegionRate && !cancelled_gc() && ((uintx)(os::random() % 1000) < ShenandoahPinRegionRate) &&
+      _injected_pin_count < MAX_INJECTED_PINS) {
+    const size_t idx = os::random() % num_regions();
+    ShenandoahHeapRegion* r = get_region(idx);
+    if ((r->is_regular() || r->is_humongous_start()) && r->has_live()) {
+      r->record_pin();
+      _injected_pin_indices[_injected_pin_count] = idx;
+      _injected_pin_count++;
+    }
+  }
+}
+
+void ShenandoahHeap::release_injected_pins() {
+  if (_injected_pin_count == 0) {
+    return;
+  }
+
+  assert(_injected_pin_count <= MAX_INJECTED_PINS,
+         "Injected pin count: %u exceeds max: %u.", _injected_pin_count, MAX_INJECTED_PINS);
+  for (uint i = 0; i < _injected_pin_count; i++) {
+    const size_t idx = _injected_pin_indices[i];
+    ShenandoahHeapRegion* r = get_region(idx);
+    assert(r->pin_count() > 0, "Region %zu in tracker must contain a pin.", idx);
+    r->record_unpin();
+  }
+  _injected_pin_count = 0;
+}
+
 void ShenandoahHeap::initialize_serviceability() {
   _memory_pool = new ShenandoahMemoryPool(this);
   _cycle_memory_manager.add_pool(_memory_pool);

src/hotspot/share/gc/shenandoah/shenandoahHeap.hpp

@@ -868,6 +868,19 @@ private:
 
   void try_inject_alloc_failure();
   bool should_inject_alloc_failure();
+
+  // Randomly pin a region when ShenandoahPinRegionRate > 0. Pin injection is only called after
+  // the cycle has populated _live_data and runs concurrently on the control thread. Releasing
+  // injected pins is done at the start of every cycle preventing stale pinned region states.
+  void try_inject_pin();
+  void release_injected_pins();
+
+  // Maximum number of regions that can be injected with pins.
+  static const uint MAX_INJECTED_PINS = 32;
+
+  // Tracker for injected pins added by try_inject_pin().
+  size_t _injected_pin_indices[MAX_INJECTED_PINS];
+  uint   _injected_pin_count;
 };
 
 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP

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

@@ -84,6 +84,7 @@ bool ShenandoahOldGC::collect(GCCause::Cause cause) {
   auto heap = ShenandoahGenerationalHeap::heap();
   assert(!_old_generation->is_doing_mixed_evacuations(), "Should not start an old gc with pending mixed evacuations");
   assert(!_old_generation->is_preparing_for_mark(), "Old regions need to be parsable during concurrent mark.");
+  heap->release_injected_pins();
 
   // Enable preemption of old generation mark.
   _allow_preemption.set();

src/hotspot/share/gc/shenandoah/shenandoah_globals.hpp

@@ -461,6 +461,12 @@
   product(bool, ShenandoahAllocFailureALot, false, DIAGNOSTIC,              \
           "Testing: make lots of artificial allocation failures.")          \
                                                                             \
+  product(uintx, ShenandoahPinRegionRate, 0, DIAGNOSTIC,                    \
+          "Testing: rate at which to artificially pin regions. Expressed "  \
+          "as N in 1000 chances for a region to be randomly pinned per "    \
+          "injection attempt.")                                             \
+          range(0, 1000)                                                    \
+                                                                            \
   product(uintx, ShenandoahCoalesceChance, 0, DIAGNOSTIC,                   \
           "Testing: Abandon remaining mixed collections with this "         \
           "likelihood. Following each mixed collection, abandon all "       \

test/hotspot/jtreg/gc/TestAllocHumongousFragment.java

@@ -71,6 +71,11 @@
  *
  * @run main/othervm -Xmx1g -Xms1g -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahTargetNumRegions=2048
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000 -XX:+ShenandoahVerify
+ *      TestAllocHumongousFragment
+ *
+ * @run main/othervm -Xmx1g -Xms1g -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahTargetNumRegions=2048
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      -XX:+ShenandoahOOMDuringEvacALot
  *      TestAllocHumongousFragment
  *
@@ -78,6 +83,11 @@
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      -XX:+ShenandoahAllocFailureALot
  *      TestAllocHumongousFragment
+ *
+ * @run main/othervm -Xmx1g -Xms1g -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahTargetNumRegions=2048
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      TestAllocHumongousFragment
  */
 
 /*

test/hotspot/jtreg/gc/shenandoah/TestAllocIntArrays.java

@@ -70,6 +70,11 @@
  *
  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000 -XX:+ShenandoahVerify
+ *      TestAllocIntArrays
+ *
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      -XX:+ShenandoahOOMDuringEvacALot
  *      TestAllocIntArrays
  *
@@ -80,6 +85,11 @@
  *
  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      TestAllocIntArrays
+ *
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      TestAllocIntArrays
  */
 

test/hotspot/jtreg/gc/shenandoah/TestAllocObjectArrays.java

@@ -70,6 +70,11 @@
  *
  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000 -XX:+ShenandoahVerify
+ *      TestAllocObjectArrays
+ *
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      -XX:+ShenandoahOOMDuringEvacALot
  *      TestAllocObjectArrays
  *
@@ -80,6 +85,11 @@
  *
  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      TestAllocObjectArrays
+ *
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      TestAllocObjectArrays
  */
 
@@ -126,6 +136,12 @@
  *
  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=adaptive -XX:ShenandoahGCMode=generational
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      -XX:+ShenandoahVerify
+ *      TestAllocObjectArrays
+ *
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -Xmx1g -Xms1g
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=adaptive -XX:ShenandoahGCMode=generational
  *      TestAllocObjectArrays
  */
 

test/hotspot/jtreg/gc/shenandoah/TestAllocObjects.java

@@ -64,6 +64,11 @@
  *      -XX:+ShenandoahAllocFailureALot -XX:+ShenandoahVerify
  *      TestAllocObjects
  *
+ * @run main/othervm/timeout=480 -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000 -XX:+ShenandoahVerify
+ *      TestAllocObjects
+ *
  * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      -XX:+ShenandoahOOMDuringEvacALot
@@ -76,6 +81,11 @@
  *
  * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      TestAllocObjects
+ *
+ * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      TestAllocObjects
  */
 

test/hotspot/jtreg/gc/shenandoah/TestJcmdHeapDump.java

@@ -58,6 +58,11 @@
  *
  * @run main/othervm/timeout=480 -Xmx16m -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      TestJcmdHeapDump
+ *
+ * @run main/othervm/timeout=480 -Xmx16m -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      TestJcmdHeapDump
  */
 

test/hotspot/jtreg/gc/shenandoah/TestLotsOfCycles.java

@@ -58,6 +58,12 @@
  *
  * @run main/othervm/timeout=480 -Xmx16m -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      -Dtarget=1000
+ *      TestLotsOfCycles
+ *
+ * @run main/othervm/timeout=480 -Xmx16m -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      -Dtarget=1000
  *      TestLotsOfCycles
  */

test/hotspot/jtreg/gc/shenandoah/TestRetainObjects.java

@@ -66,6 +66,11 @@
  *
  * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      TestRetainObjects
+ *
+ * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      TestRetainObjects
  */
 
@@ -106,6 +111,11 @@
  *
  * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=adaptive -XX:ShenandoahGCMode=generational
+ *      -XX:ShenandoahPinRegionRate=1000 -XX:+ShenandoahVerify
+ *      TestRetainObjects
+ *
+ * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=adaptive -XX:ShenandoahGCMode=generational
  *      TestRetainObjects
  */
 

test/hotspot/jtreg/gc/shenandoah/TestSieveObjects.java

@@ -68,6 +68,11 @@
  *      -XX:+ShenandoahAllocFailureALot
  *      TestSieveObjects
  *
+ * @run main/othervm/timeout=240 -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      TestSieveObjects
+ *
  * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      TestSieveObjects
@@ -108,6 +113,11 @@
  *      -XX:+ShenandoahAllocFailureALot -XX:+ShenandoahVerify
  *      TestSieveObjects
  *
+ * @run main/othervm/timeout=480 -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=adaptive -XX:ShenandoahGCMode=generational
+ *      -XX:ShenandoahPinRegionRate=1000 -XX:+ShenandoahVerify
+ *      TestSieveObjects
+ *
  * @run main/othervm -Xmx1g -Xms1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=adaptive -XX:ShenandoahGCMode=generational
  *      TestSieveObjects

test/hotspot/jtreg/gc/stress/gcbasher/TestGCBasherWithShenandoah.java

@@ -66,6 +66,11 @@ import java.io.IOException;
  *
  * @run main/othervm/timeout=200 -Xlog:gc*=info -Xmx1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      gc.stress.gcbasher.TestGCBasherWithShenandoah 120000
+ *
+ * @run main/othervm/timeout=200 -Xlog:gc*=info -Xmx1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      gc.stress.gcbasher.TestGCBasherWithShenandoah 120000
  */
 
@@ -144,6 +149,12 @@ import java.io.IOException;
  * @run main/othervm/timeout=200 -Xlog:gc*=info,nmethod+barrier=trace -Xmx1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      -XX:+DeoptimizeNMethodBarriersALot -XX:-Inline
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      gc.stress.gcbasher.TestGCBasherWithShenandoah 120000
+ *
+ * @run main/othervm/timeout=200 -Xlog:gc*=info,nmethod+barrier=trace -Xmx1g -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:+DeoptimizeNMethodBarriersALot -XX:-Inline
  *      gc.stress.gcbasher.TestGCBasherWithShenandoah 120000
  */
 

test/hotspot/jtreg/gc/stress/gcold/TestGCOldWithShenandoah.java

@@ -71,6 +71,11 @@ package gc.stress.gcold;
  *
  * @run main/othervm -Xmx384M -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
  *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
+ *      -XX:ShenandoahPinRegionRate=1000
+ *      gc.stress.gcold.TestGCOld 50 1 20 10 10000
+ *
+ * @run main/othervm -Xmx384M -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
+ *      -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
  *      gc.stress.gcold.TestGCOld 50 1 20 10 10000
  */