Reland "Replace reduce-memory mode in idle notification with delayed clean-up GC."

src/heap/heap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
 #include "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/counters.h"
 #include "src/globals.h"
 #include "src/heap/gc-idle-time-handler.h"
 #include "src/heap/gc-tracer.h"
 #include "src/heap/incremental-marking.h"
 #include "src/heap/mark-compact.h"
+#include "src/heap/memory-reducer.h"
 #include "src/heap/objects-visiting.h"
 #include "src/heap/spaces.h"
 #include "src/heap/store-buffer.h"
 #include "src/list.h"
 #include "src/splay-tree-inl.h"
 
 namespace v8 {
 namespace internal {
 
 // Defines all the roots in Heap.
@@ skipping 796 matching lines @@
 
   // Last hope GC, should try to squeeze as much as possible.
   void CollectAllAvailableGarbage(const char* gc_reason = NULL);
 
   // Check whether the heap is currently iterable.
   bool IsHeapIterable();
 
   // Notify the heap that a context has been disposed.
   int NotifyContextDisposed(bool dependant_context);
 
+  // Start incremental marking and ensure that idle time handler can perform
+  // incremental steps.
+  void StartIdleIncrementalMarking();
+
   inline void increment_scan_on_scavenge_pages() {
     scan_on_scavenge_pages_++;
     if (FLAG_gc_verbose) {
       PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
     }
   }
 
   inline void decrement_scan_on_scavenge_pages() {
     scan_on_scavenge_pages_--;
     if (FLAG_gc_verbose) {
@@ skipping 766 matching lines @@
   // marking or scavenge phase.
   void FreeDeadArrayBuffers(bool from_scavenge);
 
   // Prepare for a new scavenge phase. A new marking phase is implicitly
   // prepared by finishing the previous one.
   void PrepareArrayBufferDiscoveryInNewSpace();
 
   // An ArrayBuffer moved from new space to old space.
   void PromoteArrayBuffer(Object* buffer);
 
+  bool HasLowAllocationRate();
+  bool HasHighFragmentation();
+  bool HasHighFragmentation(intptr_t used, intptr_t committed);
+
  protected:
   // Methods made available to tests.
 
   // Allocates a JS Map in the heap.
   MUST_USE_RESULT AllocationResult
       AllocateMap(InstanceType instance_type, int instance_size,
                   ElementsKind elements_kind = TERMINAL_FAST_ELEMENTS_KIND);
 
   // Allocates and initializes a new JavaScript object based on a
   // constructor.
@@ skipping 140 matching lines @@
   // remain until the next failure and garbage collection.
   int allocation_timeout_;
 #endif  // DEBUG
 
   // Limit that triggers a global GC on the next (normally caused) GC.  This
   // is checked when we have already decided to do a GC to help determine
   // which collector to invoke, before expanding a paged space in the old
   // generation and on every allocation in large object space.
   intptr_t old_generation_allocation_limit_;
 
-  // The allocation limit when there is >16.66ms idle time in the idle time
-  // handler.
-  intptr_t idle_old_generation_allocation_limit_;
-
   // Indicates that an allocation has failed in the old generation since the
   // last GC.
   bool old_gen_exhausted_;
 
   // Indicates that inline bump-pointer allocation has been globally disabled
   // for all spaces. This is used to disable allocations in generated code.
   bool inline_allocation_disabled_;
 
   // Weak list heads, threaded through the objects.
   // List heads are initialized lazily and contain the undefined_value at start.
@@ skipping 456 matching lines @@
   bool IsHighSurvivalRate() { return high_survival_rate_period_length_ > 0; }
 
   void ConfigureInitialOldGenerationSize();
 
   void ConfigureNewGenerationSize();
 
   void SelectScavengingVisitorsTable();
 
   bool HasLowYoungGenerationAllocationRate();
   bool HasLowOldGenerationAllocationRate();
-  bool HasLowAllocationRate();
 
   void ReduceNewSpaceSize();
 
   bool TryFinalizeIdleIncrementalMarking(
       double idle_time_in_ms, size_t size_of_objects,
       size_t mark_compact_speed_in_bytes_per_ms);
 
   GCIdleTimeHandler::HeapState ComputeHeapState();
 
   bool PerformIdleTimeAction(GCIdleTimeAction action,
@@ skipping 46 matching lines @@
   MarkCompactCollector mark_compact_collector_;
 
   StoreBuffer store_buffer_;
 
   Marking marking_;
 
   IncrementalMarking incremental_marking_;
 
   GCIdleTimeHandler gc_idle_time_handler_;
 
+  MemoryReducer memory_reducer_;
+
   // These two counters are monotomically increasing and never reset.
   size_t full_codegen_bytes_generated_;
   size_t crankshaft_codegen_bytes_generated_;
 
   // This counter is increased before each GC and never reset.
   // To account for the bytes allocated since the last GC, use the
   // NewSpaceAllocationCounter() function.
   size_t new_space_allocation_counter_;
 
   // This counter is increased before each GC and never reset. To
@@ skipping 521 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_H_