Fix logic for doing incremental marking steps on tenured allocation.

R=hpayer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1040233003

Cr-Commit-Position: refs/heads/master@{#27883}

src/heap/incremental-marking.cc

@@ -815,7 +815,7 @@ void IncrementalMarking::OldSpaceStep(intptr_t allocated) {
   if (IsStopped() && ShouldActivate()) {
     Start();
   } else {
-    Step(allocated * kFastMarking / kInitialMarkingSpeed, GC_VIA_STACK_GUARD);
+    Step(allocated * kOldSpaceAllocationMarkingFactor, GC_VIA_STACK_GUARD);
   }
 }
 
@@ -891,8 +891,7 @@ intptr_t IncrementalMarking::Step(intptr_t allocated_bytes,
                                   ForceMarkingAction marking,
                                   ForceCompletionAction completion) {
   if (heap_->gc_state() != Heap::NOT_IN_GC || !FLAG_incremental_marking ||
-      !FLAG_incremental_marking_steps ||
-      (state_ != SWEEPING && state_ != MARKING)) {
+      !CanDoSteps()) {
     return 0;
   }
 

src/heap/incremental-marking.h

@@ -50,7 +50,10 @@ class IncrementalMarking {
 
   INLINE(bool IsMarking()) { return state() >= MARKING; }
 
-  inline bool IsMarkingIncomplete() { return state() == MARKING; }
+  inline bool CanDoSteps() {
+    return FLAG_incremental_marking_steps &&
+           (state() == MARKING || state() == SWEEPING);
+  }
 
   inline bool IsComplete() { return state() == COMPLETE; }
 
@@ -102,6 +105,8 @@ class IncrementalMarking {
   // But if we are promoting a lot of data we need to mark faster to keep up
   // with the data that is entering the old space through promotion.
   static const intptr_t kFastMarking = 3;
+  static const intptr_t kOldSpaceAllocationMarkingFactor =
+      kFastMarking / kInitialMarkingSpeed;
   // After this many steps we increase the marking/allocating factor.
   static const intptr_t kMarkingSpeedAccellerationInterval = 1024;
   // This is how much we increase the marking/allocating factor by.

src/heap/spaces.cc

@@ -2202,6 +2202,7 @@ void FreeList::Reset() {
   medium_list_.Reset();
   large_list_.Reset();
   huge_list_.Reset();
+  unreported_allocation_ = 0;
 }
 
 
@@ -2349,6 +2350,15 @@ FreeSpace* FreeList::FindNodeFor(int size_in_bytes, int* node_size) {
 }
 
 
+void PagedSpace::SetTopAndLimit(Address top, Address limit) {
+  DCHECK(top == limit ||
+         Page::FromAddress(top) == Page::FromAddress(limit - 1));
+  MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
+  allocation_info_.set_top(top);
+  allocation_info_.set_limit(limit);
+}
+
+
 // Allocation on the old space free list.  If it succeeds then a new linear
 // allocation space has been set up with the top and limit of the space.  If
 // the allocation fails then NULL is returned, and the caller can perform a GC
@@ -2366,9 +2376,6 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
   // if it is big enough.
   owner_->Free(owner_->top(), old_linear_size);
 
-  owner_->heap()->incremental_marking()->OldSpaceStep(size_in_bytes -
-                                                      old_linear_size);
-
   int new_node_size = 0;
   FreeSpace* new_node = FindNodeFor(size_in_bytes, &new_node_size);
   if (new_node == NULL) {
@@ -2391,21 +2398,27 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
   // candidate.
   DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(new_node));
 
-  const int kThreshold = IncrementalMarking::kAllocatedThreshold;
+  // An old-space step will mark more data per byte allocated, because old space
+  // allocation is more serious.  We don't want the pause to be bigger, so we
+  // do marking after a smaller amount of allocation.
+  const int kThreshold = IncrementalMarking::kAllocatedThreshold *
+                         IncrementalMarking::kOldSpaceAllocationMarkingFactor;
 
   // Memory in the linear allocation area is counted as allocated.  We may free
   // a little of this again immediately - see below.
   owner_->Allocate(new_node_size);
 
+  unreported_allocation_ += new_node_size;
+
   if (owner_->heap()->inline_allocation_disabled()) {
     // Keep the linear allocation area empty if requested to do so, just
     // return area back to the free list instead.
     owner_->Free(new_node->address() + size_in_bytes, bytes_left);
     DCHECK(owner_->top() == NULL && owner_->limit() == NULL);
   } else if (bytes_left > kThreshold &&
-             owner_->heap()->incremental_marking()->IsMarkingIncomplete() &&
-             FLAG_incremental_marking_steps) {
+             owner_->heap()->incremental_marking()->CanDoSteps()) {
     int linear_size = owner_->RoundSizeDownToObjectAlignment(kThreshold);
+
     // We don't want to give too large linear areas to the allocator while
     // incremental marking is going on, because we won't check again whether
     // we want to do another increment until the linear area is used up.
@@ -2413,15 +2426,27 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
                  new_node_size - size_in_bytes - linear_size);
     owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
                            new_node->address() + size_in_bytes + linear_size);
-  } else if (bytes_left > 0) {
-    // Normally we give the rest of the node to the allocator as its new
-    // linear allocation area.
-    owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
-                           new_node->address() + new_node_size);
+    owner_->heap()->incremental_marking()->OldSpaceStep(size_in_bytes +
+                                                        linear_size);
+    unreported_allocation_ = 0;
   } else {
-    // TODO(gc) Try not freeing linear allocation region when bytes_left
-    // are zero.
-    owner_->SetTopAndLimit(NULL, NULL);
+    if (unreported_allocation_ > kThreshold) {
+      // This may start the incremental marker, or do a little work if it's
+      // already started.
+      owner_->heap()->incremental_marking()->OldSpaceStep(
+          Min(kThreshold, unreported_allocation_));
+      unreported_allocation_ = 0;
+    }
+    if (bytes_left > 0) {
+      // Normally we give the rest of the node to the allocator as its new
+      // linear allocation area.
+      owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
+                             new_node->address() + new_node_size);
+    } else {
+      // TODO(gc) Try not freeing linear allocation region when bytes_left
+      // are zero.
+      owner_->SetTopAndLimit(NULL, NULL);
+    }
   }
 
   return new_node;
@@ -2908,7 +2933,16 @@ AllocationResult LargeObjectSpace::AllocateRaw(int object_size,
     reinterpret_cast<Object**>(object->address())[1] = Smi::FromInt(0);
   }
 
-  heap()->incremental_marking()->OldSpaceStep(object_size);
+  // We would like to tell the incremental marker to do a lot of work, since
+  // we just made a large allocation in old space, but that might cause a huge
+  // pause. Underreporting here may cause the marker to speed up because it
+  // will perceive that it is not keeping up with allocation. Although this
+  // causes some big incremental marking steps they are not as big as this one
+  // might have been. In testing, a very large pause was divided up into about
+  // 12 parts.
+  const int kThreshold = IncrementalMarking::kAllocatedThreshold *
+                         IncrementalMarking::kOldSpaceAllocationMarkingFactor;
+  heap()->incremental_marking()->OldSpaceStep(kThreshold);
   return object;
 }
 

src/heap/spaces.h

@@ -1574,6 +1574,7 @@ class FreeList {
 
   PagedSpace* owner_;
   Heap* heap_;
+  int unreported_allocation_;
 
   static const int kSmallListMax = 0xff * kPointerSize;
   static const int kMediumListMax = 0x7ff * kPointerSize;
@@ -1771,13 +1772,7 @@ class PagedSpace : public Space {
   void ResetFreeList() { free_list_.Reset(); }
 
   // Set space allocation info.
-  void SetTopAndLimit(Address top, Address limit) {
-    DCHECK(top == limit ||
-           Page::FromAddress(top) == Page::FromAddress(limit - 1));
-    MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
-    allocation_info_.set_top(top);
-    allocation_info_.set_limit(limit);
-  }
+  void SetTopAndLimit(Address top, Address limit);
 
   // Empty space allocation info, returning unused area to free list.
   void EmptyAllocationInfo() {