# HG changeset patch
# Parent  5b2f501173749e960a53f2a9f48ac4a58e20f8f3
8234974: Shenandoah: Do concurrent roots even when no evacuation is necessary

diff -r 5b2f50117374 src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp	Wed Dec 11 15:01:11 2019 -0500
+++ b/src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp	Wed Dec 11 22:05:55 2019 +0100
@@ -264,13 +264,8 @@
   }
 
   ShenandoahMarkingContext* const marking_context = _heap->marking_context();
-  if (_heap->is_evacuation_in_progress() && !marking_context->is_marked(obj)) {
-    Thread* thr = Thread::current();
-    if (thr->is_Java_thread()) {
-      return NULL;
-    } else {
-      return obj;
-    }
+  if (_heap->is_concurrent_root_in_progress() && !marking_context->is_marked(obj)) {
+    return NULL;
   }
 
   oop fwd = load_reference_barrier_not_null(obj);
diff -r 5b2f50117374 src/hotspot/share/gc/shenandoah/shenandoahBarrierSetNMethod.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahBarrierSetNMethod.cpp	Wed Dec 11 15:01:11 2019 -0500
+++ b/src/hotspot/share/gc/shenandoah/shenandoahBarrierSetNMethod.cpp	Wed Dec 11 22:05:55 2019 +0100
@@ -57,8 +57,10 @@
   }
 
   // Heal oops and disarm
-  ShenandoahEvacOOMScope scope;
-  ShenandoahNMethod::heal_nmethod(nm);
+  if (ShenandoahHeap::heap()->is_evacuation_in_progress()) {
+    ShenandoahEvacOOMScope scope;
+    ShenandoahNMethod::heal_nmethod(nm);
+  }
   ShenandoahNMethod::disarm_nmethod(nm);
   return true;
 }
diff -r 5b2f50117374 src/hotspot/share/gc/shenandoah/shenandoahClosures.inline.hpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahClosures.inline.hpp	Wed Dec 11 15:01:11 2019 -0500
+++ b/src/hotspot/share/gc/shenandoah/shenandoahClosures.inline.hpp	Wed Dec 11 22:05:55 2019 +0100
@@ -111,12 +111,13 @@
 
 template <class T>
 void ShenandoahEvacuateUpdateRootsClosure::do_oop_work(T* p) {
-  assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
+  assert(_heap->is_concurrent_root_in_progress(), "Only do this when evacuation is in progress");
 
   T o = RawAccess<>::oop_load(p);
   if (! CompressedOops::is_null(o)) {
     oop obj = CompressedOops::decode_not_null(o);
     if (_heap->in_collection_set(obj)) {
+      assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
       shenandoah_assert_marked(p, obj);
       oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
       if (resolved == obj) {
@@ -139,11 +140,12 @@
 }
 
 void ShenandoahEvacUpdateOopStorageRootsClosure::do_oop(oop* p) {
-  assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
+  assert(_heap->is_concurrent_root_in_progress(), "Only do this when evacuation is in progress");
 
   oop obj = RawAccess<>::oop_load(p);
   if (! CompressedOops::is_null(obj)) {
     if (_heap->in_collection_set(obj)) {
+      assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
       shenandoah_assert_marked(p, obj);
       oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
       if (resolved == obj) {
diff -r 5b2f50117374 src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp	Wed Dec 11 15:01:11 2019 -0500
+++ b/src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp	Wed Dec 11 22:05:55 2019 +0100
@@ -224,7 +224,9 @@
 
     // Heal oops and disarm
     ShenandoahEvacOOMScope evac_scope;
-    ShenandoahNMethod::heal_nmethod(nm);
+    if (_heap->is_evacuation_in_progress()) {
+      ShenandoahNMethod::heal_nmethod(nm);
+    }
     ShenandoahNMethod::disarm_nmethod(nm);
 
     // Clear compiled ICs and exception caches
diff -r 5b2f50117374 src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	Wed Dec 11 15:01:11 2019 -0500
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	Wed Dec 11 22:05:55 2019 +0100
@@ -542,6 +542,7 @@
   if (is_degenerated_gc_in_progress())       st->print("degenerated gc, ");
   if (is_full_gc_in_progress())              st->print("full gc, ");
   if (is_full_gc_move_in_progress())         st->print("full gc move, ");
+  if (is_concurrent_root_in_progress())      st->print("concurrent roots, ");
 
   if (cancelled_gc()) {
     st->print("cancelled");
@@ -1540,6 +1541,11 @@
       _free_set->rebuild();
     }
 
+    if (!is_degenerated_gc_in_progress()) {
+      prepare_concurrent_roots();
+      prepare_concurrent_unloading();
+    }
+
     // If collection set has candidates, start evacuation.
     // Otherwise, bypass the rest of the cycle.
     if (!collection_set()->is_empty()) {
@@ -1554,8 +1560,6 @@
       set_has_forwarded_objects(true);
 
       if (!is_degenerated_gc_in_progress()) {
-        prepare_concurrent_roots();
-        prepare_concurrent_unloading();
         evacuate_and_update_roots();
       }
 
@@ -1669,12 +1673,12 @@
 };
 
 void ShenandoahHeap::op_roots() {
-  if (is_evacuation_in_progress()) {
+  if (is_concurrent_root_in_progress()) {
     if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
       _unloader.unload();
     }
 
-    if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
+    if (ShenandoahConcurrentRoots::should_do_concurrent_roots() && is_concurrent_root_in_progress()) {
       ShenandoahConcurrentRootsEvacUpdateTask task;
       workers()->run_task(&task);
     }
diff -r 5b2f50117374 src/hotspot/share/gc/shenandoah/shenandoahUnload.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahUnload.cpp	Wed Dec 11 15:01:11 2019 -0500
+++ b/src/hotspot/share/gc/shenandoah/shenandoahUnload.cpp	Wed Dec 11 22:05:55 2019 +0100
@@ -79,7 +79,7 @@
 public:
   virtual bool is_unloading(CompiledMethod* method) const {
     nmethod* const nm = method->as_nmethod();
-    guarantee(ShenandoahHeap::heap()->is_evacuation_in_progress(), "Only this phase");
+    guarantee(ShenandoahHeap::heap()->is_concurrent_root_in_progress(), "Only this phase");
     ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
     ShenandoahReentrantLocker locker(data->lock());
     ShenandoahIsUnloadingOopClosure cl;
@@ -166,7 +166,7 @@
 
 void ShenandoahUnload::unload() {
   assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(), "Why we here?");
-  if (!ShenandoahHeap::heap()->is_evacuation_in_progress()) {
+  if (!ShenandoahHeap::heap()->is_concurrent_root_in_progress()) {
     return;
   }