[heap] Ensure quick progress of incremental marking near OOM.

src/heap/incremental-marking.cc

 // 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.
 
 #include "src/heap/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
 #include "src/conversions.h"
 #include "src/heap/gc-idle-time-handler.h"
@@ skipping 1051 matching lines @@
   old_generation_allocation_counter_ = current_counter;
   return bytes_allocated_;
 }
 
 size_t IncrementalMarking::StepSizeToMakeProgress() {
   // We increase step size gradually based on the time passed in order to
   // leave marking work to standalone tasks. The ramp up duration and the
   // target step count are chosen based on benchmarks.
   const int kRampUpIntervalMs = 300;
   const size_t kTargetStepCount = 128;
+  const size_t kTargetStepCountAtOOM = 16;
+  size_t oom_slack = heap()->new_space()->Capacity() + 64 * MB;
+
+  if (heap()->IsCloseToOutOfMemory(oom_slack)) {
+    return heap()->PromotedSpaceSizeOfObjects() / kTargetStepCountAtOOM;
+  }
+
   size_t step_size = Max(initial_old_generation_size_ / kTargetStepCount,
                          IncrementalMarking::kAllocatedThreshold);
   double time_passed_ms =
       heap_->MonotonicallyIncreasingTimeInMs() - start_time_ms_;
   double factor = Min(time_passed_ms / kRampUpIntervalMs, 1.0);
   return static_cast<size_t>(factor * step_size);
 }
 
 void IncrementalMarking::AdvanceIncrementalMarkingOnAllocation() {
   if (heap_->gc_state() != Heap::NOT_IN_GC || !FLAG_incremental_marking ||
@@ skipping 108 matching lines @@
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 
 }  // namespace internal
 }  // namespace v8