Prepares allocation for proper sync with mutator and bg threads.

runtime/vm/scavenger.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_SCAVENGER_H_
 #define RUNTIME_VM_SCAVENGER_H_
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/dart.h"
 #include "vm/flags.h"
 #include "vm/globals.h"
+#include "vm/lockers.h"
 #include "vm/raw_object.h"
 #include "vm/ring_buffer.h"
 #include "vm/spaces.h"
 #include "vm/virtual_memory.h"
 #include "vm/visitor.h"
 
 namespace dart {
 
 // Forward declarations.
 class Heap;
@@ skipping 95 matching lines @@
   // During a scavenge this function only returns true for addresses that will
   // be part of the surviving objects.
   bool Contains(uword addr) const { return to_->Contains(addr); }
 
   RawObject* FindObject(FindObjectVisitor* visitor) const;
 
   uword TryAllocateNewTLAB(Thread* thread, intptr_t size) {
     ASSERT(Utils::IsAligned(size, kObjectAlignment));
     ASSERT(heap_ != Dart::vm_isolate()->heap());
     ASSERT(!scavenging_);
+    MutexLocker ml(space_lock_);
     uword result = top_;
     intptr_t remaining = end_ - top_;
     if (remaining < size) {
       return 0;
     }
     ASSERT(to_->Contains(result));
     ASSERT((result & kObjectAlignmentMask) == object_alignment_);
     top_ += size;
     ASSERT(to_->Contains(top_) || (top_ == to_->end()));
     ASSERT(result < top_);
@@ skipping 90 matching lines @@
   intptr_t collections() const { return collections_; }
 
 #ifndef PRODUCT
   void PrintToJSONObject(JSONObject* object) const;
 #endif  // !PRODUCT
 
   void AllocateExternal(intptr_t size);
   void FreeExternal(intptr_t size);
 
   void MakeNewSpaceIterable() const;
-  uword FirstObjectStart() const { return to_->start() | object_alignment_; }
+  int64_t FreeSpaceInWords(Isolate* isolate) const;
+  void MakeAllTLABsIterable(Isolate* isolate) const;
+  void AbandonAllTLABs(Isolate* isolate);
 
  private:
   // Ids for time and data records in Heap::GCStats.
   enum {
     // Time
     kDummyScavengeTime = 0,
     kSafePoint = 1,
     kVisitIsolateRoots = 2,
     kIterateStoreBuffers = 3,
     kProcessToSpace = 4,
     kIterateWeaks = 5,
     // Data
     kStoreBufferEntries = 0,
     kDataUnused1 = 1,
     kDataUnused2 = 2,
     kToKBAfterStoreBuffer = 3
   };
 
+  uword FirstObjectStart() const { return to_->start() | object_alignment_; }
   SemiSpace* Prologue(Isolate* isolate, bool invoke_api_callbacks);
   void IterateStoreBuffers(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateObjectIdTable(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateRoots(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateWeakProperties(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateWeakReferences(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateWeakRoots(Isolate* isolate, HandleVisitor* visitor);
   void ProcessToSpace(ScavengerVisitor* visitor);
   void EnqueueWeakProperty(RawWeakProperty* raw_weak);
   uword ProcessWeakProperty(RawWeakProperty* raw_weak,
@@ skipping 59 matching lines @@
   int64_t gc_time_micros_;
   intptr_t collections_;
   static const int kStatsHistoryCapacity = 2;
   RingBuffer<ScavengeStats, kStatsHistoryCapacity> stats_history_;
 
   // The total size of external data associated with objects in this scavenger.
   intptr_t external_size_;
 
   bool failed_to_promote_;
 
+  // Protects new space during the allocation of new TLABs
+  Mutex* space_lock_;
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;
 
   DISALLOW_COPY_AND_ASSIGN(Scavenger);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_SCAVENGER_H_