Revert "Puts TLABs back into the build and fixes assert failure."

runtime/vm/scavenger.cc

Index: runtime/vm/scavenger.cc
diff --git a/runtime/vm/scavenger.cc b/runtime/vm/scavenger.cc
index 7da628ba93d21475ea6513303692780973d8728a..c3bbc268bd07e9937cb171c57c59eb5f5f10e853 100644
--- a/runtime/vm/scavenger.cc
+++ b/runtime/vm/scavenger.cc
@@ -324,8 +324,7 @@ Scavenger::Scavenger(Heap* heap,
       gc_time_micros_(0),
       collections_(0),
       external_size_(0),
-      failed_to_promote_(false),
-      space_lock_(new Mutex()) {
+      failed_to_promote_(false) {
   // Verify assumptions about the first word in objects which the scavenger is
   // going to use for forwarding pointers.
   ASSERT(Object::tags_offset() == 0);
@@ -356,7 +355,6 @@ Scavenger::Scavenger(Heap* heap,
 Scavenger::~Scavenger() {
   ASSERT(!scavenging_);
   to_->Delete();
-  delete space_lock_;
 }
 
 intptr_t Scavenger::NewSizeInWords(intptr_t old_size_in_words) const {
@@ -393,6 +391,13 @@ SemiSpace* Scavenger::Prologue(Isolate* isolate) {
   resolved_top_ = top_;
   end_ = to_->end();
 
+  // Throw out the old information about the from space
+  if (isolate->IsMutatorThreadScheduled()) {
+    Thread* mutator_thread = isolate->mutator_thread();
+    mutator_thread->set_top(top_);
+    mutator_thread->set_end(end_);
+  }
+
   return from;
 }
 
@@ -400,10 +405,13 @@ void Scavenger::Epilogue(Isolate* isolate, SemiSpace* from) {
   // All objects in the to space have been copied from the from space at this
   // moment.
 
-  // Ensure the mutator thread will fail the next allocation. This will force
-  // mutator to allocate a new TLAB
-  Thread* mutator_thread = isolate->mutator_thread();
-  ASSERT((mutator_thread == NULL) || (!mutator_thread->HasActiveTLAB()));
+  // Ensure the mutator thread now has the up-to-date top_ and end_ of the
+  // semispace
+  if (isolate->IsMutatorThreadScheduled()) {
+    Thread* thread = isolate->mutator_thread();
+    thread->set_top(top_);
+    thread->set_end(end_);
+  }
 
   double avg_frac = stats_history_.Get(0).PromoCandidatesSuccessFraction();
   if (stats_history_.Size() >= 2) {
@@ -706,45 +714,18 @@ void Scavenger::ProcessWeakReferences() {
   }
 }
 
-void Scavenger::MakeAllTLABsIterable(Isolate* isolate) const {
-  MonitorLocker ml(isolate->threads_lock(), false);
-  Thread* current = heap_->isolate()->thread_registry()->active_list();
-  while (current != NULL) {
-    if (current->HasActiveTLAB()) {
-      heap_->MakeTLABIterable(current);
-    }
-    current = current->next();
-  }
-  Thread* mutator_thread = isolate->mutator_thread();
-  if ((mutator_thread != NULL) && (!isolate->IsMutatorThreadScheduled())) {
-    heap_->MakeTLABIterable(mutator_thread);
-  }
-}
-
-void Scavenger::MakeNewSpaceIterable() const {
+void Scavenger::FlushTLS() const {
   ASSERT(heap_ != NULL);
-  if (!scavenging_) {
-    MakeAllTLABsIterable(heap_->isolate());
-  }
-}
-
-void Scavenger::AbandonAllTLABs(Isolate* isolate) {
-  MonitorLocker ml(isolate->threads_lock(), false);
-  Thread* current = isolate->thread_registry()->active_list();
-  while (current != NULL) {
-    heap_->AbandonRemainingTLAB(current);
-    current = current->next();
-  }
-  Thread* mutator_thread = isolate->mutator_thread();
-  if ((mutator_thread != NULL) && (!isolate->IsMutatorThreadScheduled())) {
-    heap_->AbandonRemainingTLAB(mutator_thread);
+  if (heap_->isolate()->IsMutatorThreadScheduled()) {
+    Thread* mutator_thread = heap_->isolate()->mutator_thread();
+    mutator_thread->heap()->new_space()->set_top(mutator_thread->top());
   }
 }
 
 void Scavenger::VisitObjectPointers(ObjectPointerVisitor* visitor) const {
   ASSERT(Thread::Current()->IsAtSafepoint() ||
          (Thread::Current()->task_kind() == Thread::kMarkerTask));
-  MakeNewSpaceIterable();
+  FlushTLS();
   uword cur = FirstObjectStart();
   while (cur < top_) {
     RawObject* raw_obj = RawObject::FromAddr(cur);
@@ -755,7 +736,7 @@ void Scavenger::VisitObjectPointers(ObjectPointerVisitor* visitor) const {
 void Scavenger::VisitObjects(ObjectVisitor* visitor) const {
   ASSERT(Thread::Current()->IsAtSafepoint() ||
          (Thread::Current()->task_kind() == Thread::kMarkerTask));
-  MakeNewSpaceIterable();
+  FlushTLS();
   uword cur = FirstObjectStart();
   while (cur < top_) {
     RawObject* raw_obj = RawObject::FromAddr(cur);
@@ -770,7 +751,7 @@ void Scavenger::AddRegionsToObjectSet(ObjectSet* set) const {
 
 RawObject* Scavenger::FindObject(FindObjectVisitor* visitor) const {
   ASSERT(!scavenging_);
-  MakeNewSpaceIterable();
+  FlushTLS();
   uword cur = FirstObjectStart();
   if (visitor->VisitRange(cur, top_)) {
     while (cur < top_) {
@@ -811,8 +792,6 @@ void Scavenger::Scavenge() {
   int64_t post_safe_point = OS::GetCurrentMonotonicMicros();
   heap_->RecordTime(kSafePoint, post_safe_point - pre_safe_point);
 
-  AbandonAllTLABs(isolate);
-
   // TODO(koda): Make verification more compatible with concurrent sweep.
   if (FLAG_verify_before_gc && !FLAG_concurrent_sweep) {
     OS::PrintErr("Verifying before Scavenge...");
@@ -924,6 +903,11 @@ void Scavenger::Evacuate() {
   // Forces the next scavenge to promote all the objects in the new space.
   survivor_end_ = top_;
 
+  if (heap_->isolate()->IsMutatorThreadScheduled()) {
+    Thread* mutator_thread = heap_->isolate()->mutator_thread();
+    survivor_end_ = mutator_thread->top();
+  }
+
   Scavenge();
 
   // It is possible for objects to stay in the new space
@@ -931,28 +915,4 @@ void Scavenger::Evacuate() {
   ASSERT((UsedInWords() == 0) || failed_to_promote_);
 }
 
-int64_t Scavenger::FreeSpaceInWords(Isolate* isolate) const {
-  MonitorLocker ml(isolate->threads_lock(), false);
-  Thread* current = isolate->thread_registry()->active_list();
-  int64_t free_space = 0;
-  while (current != NULL) {
-    if (current->HasActiveTLAB()) {
-      free_space += current->end() - current->top();
-    }
-    current = current->next();
-  }
-
-  Thread* mutator_thread = isolate->mutator_thread();
-  if ((mutator_thread != NULL) && (!isolate->IsMutatorThreadScheduled())) {
-    free_space += mutator_thread->end() - mutator_thread->top();
-  }
-  return free_space >> kWordSizeLog2;
-}
-
-int64_t Scavenger::UsedInWords() const {
-  int64_t free_space_in_tlab = FreeSpaceInWords(heap_->isolate());
-  int64_t max_space_used = (top_ - FirstObjectStart()) >> kWordSizeLog2;
-  return max_space_used - free_space_in_tlab;
-}
-
 }  // namespace dart