Reland "Reland "[profiler] proper observation of old space inline allocations""

This is a reland of ec952aaa.

Included is a fix that ensures that top_on_previous_step_ is cleared when we
release a page.

Original change's description:
> Reland "[profiler] proper observation of old space inline allocations"
>
> This is a reland of 672a41c3
> Original change's description:
> > [profiler] proper observation of old space inline allocations
> >
> > Bug: chromium:633920
> > Change-Id: I9a2f4a89f6b9c0f63cb3b166b06a88a12f0a203c
> > Reviewed-on: https://chromium-review.googlesource.com/631696
> > Commit-Queue: Ali Ijaz Sheikh <ofrobots@google.com>
> > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#48043}
>
> Bug: chromium:633920
> Change-Id: I6fe743d31b8ff26f3858488d4c014c62d3c85add
> Reviewed-on: https://chromium-review.googlesource.com/671127
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Ali Ijaz Sheikh <ofrobots@google.com>
> Cr-Commit-Position: refs/heads/master@{#48085}

Bug: chromium:633920
Change-Id: I8a0dcc4eaffc1f1d3ac5b3f8d344001cdae36606
Reviewed-on: https://chromium-review.googlesource.com/677407Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ali Ijaz Sheikh <ofrobots@google.com>
Cr-Commit-Position: refs/heads/master@{#48141}

src/heap/spaces-inl.h

@@ -369,6 +369,16 @@ AllocationResult PagedSpace::AllocateRawAligned(int size_in_bytes,
 
 AllocationResult PagedSpace::AllocateRaw(int size_in_bytes,
                                          AllocationAlignment alignment) {
+  if (top() < top_on_previous_step_) {
+    // Generated code decreased the top() pointer to do folded allocations
+    DCHECK_EQ(Page::FromAddress(top()),
+              Page::FromAddress(top_on_previous_step_));
+    top_on_previous_step_ = top();
+  }
+  size_t bytes_since_last =
+      top_on_previous_step_ ? top() - top_on_previous_step_ : 0;
+
+  DCHECK_IMPLIES(!SupportsInlineAllocation(), bytes_since_last == 0);
 #ifdef V8_HOST_ARCH_32_BIT
   AllocationResult result =
       alignment == kDoubleAligned
@@ -378,11 +388,13 @@ AllocationResult PagedSpace::AllocateRaw(int size_in_bytes,
   AllocationResult result = AllocateRawUnaligned(size_in_bytes);
 #endif
   HeapObject* heap_obj = nullptr;
-  if (!result.IsRetry() && result.To(&heap_obj)) {
-    AllocationStep(heap_obj->address(), size_in_bytes);
+  if (!result.IsRetry() && result.To(&heap_obj) && !is_local()) {
+    AllocationStep(static_cast<int>(size_in_bytes + bytes_since_last),
+                   heap_obj->address(), size_in_bytes);
     DCHECK_IMPLIES(
         heap()->incremental_marking()->black_allocation(),
         heap()->incremental_marking()->marking_state()->IsBlack(heap_obj));
+    StartNextInlineAllocationStep();
   }
   return result;
 }

src/heap/spaces.cc

@@ -1328,6 +1328,7 @@ STATIC_ASSERT(static_cast<ObjectSpace>(1 << AllocationSpace::MAP_SPACE) ==
 
 void Space::AddAllocationObserver(AllocationObserver* observer) {
   allocation_observers_.push_back(observer);
+  StartNextInlineAllocationStep();
 }
 
 void Space::RemoveAllocationObserver(AllocationObserver* observer) {
@@ -1335,6 +1336,7 @@ void Space::RemoveAllocationObserver(AllocationObserver* observer) {
                       allocation_observers_.end(), observer);
   DCHECK(allocation_observers_.end() != it);
   allocation_observers_.erase(it);
+  StartNextInlineAllocationStep();
 }
 
 void Space::PauseAllocationObservers() { allocation_observers_paused_ = true; }
@@ -1343,11 +1345,12 @@ void Space::ResumeAllocationObservers() {
   allocation_observers_paused_ = false;
 }
 
-void Space::AllocationStep(Address soon_object, int size) {
+void Space::AllocationStep(int bytes_since_last, Address soon_object,
+                           int size) {
   if (!allocation_observers_paused_) {
     heap()->CreateFillerObjectAt(soon_object, size, ClearRecordedSlots::kNo);
     for (AllocationObserver* observer : allocation_observers_) {
-      observer->AllocationStep(size, soon_object, size);
+      observer->AllocationStep(bytes_since_last, soon_object, size);
     }
   }
 }
@@ -1367,7 +1370,8 @@ PagedSpace::PagedSpace(Heap* heap, AllocationSpace space,
     : Space(heap, space, executable),
       anchor_(this),
       free_list_(this),
-      locked_page_(nullptr) {
+      locked_page_(nullptr),
+      top_on_previous_step_(0) {
   area_size_ = MemoryAllocator::PageAreaSize(space);
   accounting_stats_.Clear();
 
@@ -1596,6 +1600,48 @@ void PagedSpace::SetAllocationInfo(Address top, Address limit) {
   }
 }
 
+void PagedSpace::DecreaseLimit(Address new_limit) {
+  Address old_limit = limit();
+  DCHECK_LE(top(), new_limit);
+  DCHECK_GE(old_limit, new_limit);
+  if (new_limit != old_limit) {
+    SetTopAndLimit(top(), new_limit);
+    Free(new_limit, old_limit - new_limit);
+    if (heap()->incremental_marking()->black_allocation()) {
+      Page::FromAllocationAreaAddress(new_limit)->DestroyBlackArea(new_limit,
+                                                                   old_limit);
+    }
+  }
+}
+
+Address PagedSpace::ComputeLimit(Address start, Address end,
+                                 size_t size_in_bytes) {
+  DCHECK_GE(end - start, size_in_bytes);
+
+  if (heap()->inline_allocation_disabled()) {
+    // Keep the linear allocation area to fit exactly the requested size.
+    return start + size_in_bytes;
+  } else if (!allocation_observers_paused_ && !allocation_observers_.empty() &&
+             identity() == OLD_SPACE && !is_local()) {
+    // Generated code may allocate inline from the linear allocation area for
+    // Old Space. To make sure we can observe these allocations, we use a lower
+    // limit.
+    size_t step = RoundSizeDownToObjectAlignment(
+        static_cast<int>(GetNextInlineAllocationStepSize()));
+    return Max(start + size_in_bytes, Min(start + step, end));
+  } else {
+    // The entire node can be used as the linear allocation area.
+    return end;
+  }
+}
+
+void PagedSpace::StartNextInlineAllocationStep() {
+  if (!allocation_observers_paused_ && SupportsInlineAllocation()) {
+    top_on_previous_step_ = allocation_observers_.empty() ? 0 : top();
+    DecreaseLimit(ComputeLimit(top(), limit(), 0));
+  }
+}
+
 void PagedSpace::MarkAllocationInfoBlack() {
   DCHECK(heap()->incremental_marking()->black_allocation());
   Address current_top = top();
@@ -1641,6 +1687,12 @@ void PagedSpace::EmptyAllocationInfo() {
     }
   }
 
+  if (top_on_previous_step_) {
+    DCHECK(current_top >= top_on_previous_step_);
+    AllocationStep(static_cast<int>(current_top - top_on_previous_step_),
+                   nullptr, 0);
+    top_on_previous_step_ = 0;
+  }
   SetTopAndLimit(NULL, NULL);
   DCHECK_GE(current_limit, current_top);
   Free(current_top, current_limit - current_top);
@@ -1656,6 +1708,7 @@ void PagedSpace::ReleasePage(Page* page) {
   DCHECK(!free_list_.ContainsPageFreeListItems(page));
 
   if (Page::FromAllocationAreaAddress(allocation_info_.top()) == page) {
+    DCHECK(!top_on_previous_step_);
     allocation_info_.Reset(nullptr, nullptr);
   }
 
@@ -2088,16 +2141,6 @@ void NewSpace::StartNextInlineAllocationStep() {
   }
 }
 
-void NewSpace::AddAllocationObserver(AllocationObserver* observer) {
-  Space::AddAllocationObserver(observer);
-  StartNextInlineAllocationStep();
-}
-
-void NewSpace::RemoveAllocationObserver(AllocationObserver* observer) {
-  Space::RemoveAllocationObserver(observer);
-  StartNextInlineAllocationStep();
-}
-
 void NewSpace::PauseAllocationObservers() {
   // Do a step to account for memory allocated so far.
   InlineAllocationStep(top(), top(), nullptr, 0);
@@ -2106,12 +2149,28 @@ void NewSpace::PauseAllocationObservers() {
   UpdateInlineAllocationLimit(0);
 }
 
+void PagedSpace::PauseAllocationObservers() {
+  // Do a step to account for memory allocated so far.
+  if (top_on_previous_step_) {
+    int bytes_allocated = static_cast<int>(top() - top_on_previous_step_);
+    AllocationStep(bytes_allocated, nullptr, 0);
+  }
+  Space::PauseAllocationObservers();
+  top_on_previous_step_ = 0;
+}
+
 void NewSpace::ResumeAllocationObservers() {
   DCHECK_NULL(top_on_previous_step_);
   Space::ResumeAllocationObservers();
   StartNextInlineAllocationStep();
 }
 
+// TODO(ofrobots): refactor into SpaceWithLinearArea
+void PagedSpace::ResumeAllocationObservers() {
+  DCHECK(top_on_previous_step_ == 0);
+  Space::ResumeAllocationObservers();
+  StartNextInlineAllocationStep();
+}
 
 void NewSpace::InlineAllocationStep(Address top, Address new_top,
                                     Address soon_object, size_t size) {
@@ -2886,7 +2945,6 @@ bool FreeList::Allocate(size_t size_in_bytes) {
   if (new_node == nullptr) return false;
 
   DCHECK_GE(new_node_size, size_in_bytes);
-  size_t bytes_left = new_node_size - size_in_bytes;
 
 #ifdef DEBUG
   for (size_t i = 0; i < size_in_bytes / kPointerSize; i++) {
@@ -2900,38 +2958,21 @@ bool FreeList::Allocate(size_t size_in_bytes) {
   // candidate.
   DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(new_node));
 
-  const size_t kThreshold = IncrementalMarking::kAllocatedThreshold;
-
   // Memory in the linear allocation area is counted as allocated.  We may free
   // a little of this again immediately - see below.
   owner_->IncreaseAllocatedBytes(new_node_size,
                                  Page::FromAddress(new_node->address()));
 
-  if (owner_->heap()->inline_allocation_disabled()) {
-    // Keep the linear allocation area to fit exactly the requested size.
-    // Return the rest to the free list.
-    owner_->Free(new_node->address() + size_in_bytes, bytes_left);
-    owner_->SetAllocationInfo(new_node->address(),
-                              new_node->address() + size_in_bytes);
-  } else if (bytes_left > kThreshold &&
-             owner_->heap()->incremental_marking()->IsMarkingIncomplete() &&
-             FLAG_incremental_marking &&
-             !owner_->is_local()) {  // Not needed on CompactionSpaces.
-    size_t 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.
-    DCHECK_GE(new_node_size, size_in_bytes + linear_size);
-    owner_->Free(new_node->address() + size_in_bytes + linear_size,
-                 new_node_size - size_in_bytes - linear_size);
-    owner_->SetAllocationInfo(
-        new_node->address(), new_node->address() + size_in_bytes + linear_size);
-  } else {
-    // Normally we give the rest of the node to the allocator as its new
-    // linear allocation area.
-    owner_->SetAllocationInfo(new_node->address(),
-                              new_node->address() + new_node_size);
+  Address start = new_node->address();
+  Address end = new_node->address() + new_node_size;
+  Address limit = owner_->ComputeLimit(start, end, size_in_bytes);
+  DCHECK_LE(limit, end);
+  DCHECK_LE(size_in_bytes, limit - start);
+  if (limit != end) {
+    owner_->Free(limit, end - limit);
   }
+  owner_->SetAllocationInfo(start, limit);
+
   return true;
 }
 
@@ -3319,7 +3360,7 @@ AllocationResult LargeObjectSpace::AllocateRaw(int object_size,
   if (heap()->incremental_marking()->black_allocation()) {
     heap()->incremental_marking()->marking_state()->WhiteToBlack(object);
   }
-  AllocationStep(object->address(), object_size);
+  AllocationStep(object_size, object->address(), object_size);
   DCHECK_IMPLIES(
       heap()->incremental_marking()->black_allocation(),
       heap()->incremental_marking()->marking_state()->IsBlack(object));

src/heap/spaces.h

@@ -903,17 +903,17 @@ class Space : public Malloced {
   // Identity used in error reporting.
   AllocationSpace identity() { return id_; }
 
-  V8_EXPORT_PRIVATE virtual void AddAllocationObserver(
-      AllocationObserver* observer);
+  void AddAllocationObserver(AllocationObserver* observer);
 
-  V8_EXPORT_PRIVATE virtual void RemoveAllocationObserver(
-      AllocationObserver* observer);
+  void RemoveAllocationObserver(AllocationObserver* observer);
 
   V8_EXPORT_PRIVATE virtual void PauseAllocationObservers();
 
   V8_EXPORT_PRIVATE virtual void ResumeAllocationObservers();
 
-  void AllocationStep(Address soon_object, int size);
+  V8_EXPORT_PRIVATE virtual void StartNextInlineAllocationStep() {}
+
+  void AllocationStep(int bytes_since_last, Address soon_object, int size);
 
   // Return the total amount committed memory for this space, i.e., allocatable
   // memory and page headers.
@@ -2071,15 +2071,8 @@ class V8_EXPORT_PRIVATE PagedSpace : NON_EXPORTED_BASE(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_.Reset(top, limit);
-  }
-
-  void SetAllocationInfo(Address top, Address limit);
+  void PauseAllocationObservers() override;
+  void ResumeAllocationObservers() override;
 
   // Empty space allocation info, returning unused area to free list.
   void EmptyAllocationInfo();
@@ -2184,6 +2177,21 @@ class V8_EXPORT_PRIVATE PagedSpace : NON_EXPORTED_BASE(public Space) {
   // multiple tasks hold locks on pages while trying to sweep each others pages.
   void AnnounceLockedPage(Page* page) { locked_page_ = page; }
 
+  Address ComputeLimit(Address start, Address end, size_t size_in_bytes);
+  void SetAllocationInfo(Address top, Address limit);
+
+ private:
+  // 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_.Reset(top, limit);
+  }
+  void DecreaseLimit(Address new_limit);
+  void StartNextInlineAllocationStep() override;
+  bool SupportsInlineAllocation() { return identity() == OLD_SPACE; }
+
  protected:
   // PagedSpaces that should be included in snapshots have different, i.e.,
   // smaller, initial pages.
@@ -2246,6 +2254,7 @@ class V8_EXPORT_PRIVATE PagedSpace : NON_EXPORTED_BASE(public Space) {
   base::Mutex space_mutex_;
 
   Page* locked_page_;
+  Address top_on_previous_step_;
 
   friend class IncrementalMarking;
   friend class MarkCompactCollector;
@@ -2647,14 +2656,6 @@ class NewSpace : public Space {
     UpdateInlineAllocationLimit(0);
   }
 
-  // Allows observation of inline allocation. The observer->Step() method gets
-  // called after every step_size bytes have been allocated (approximately).
-  // This works by adjusting the allocation limit to a lower value and adjusting
-  // it after each step.
-  void AddAllocationObserver(AllocationObserver* observer) override;
-
-  void RemoveAllocationObserver(AllocationObserver* observer) override;
-
   // Get the extent of the inactive semispace (for use as a marking stack,
   // or to zap it). Notice: space-addresses are not necessarily on the
   // same page, so FromSpaceStart() might be above FromSpaceEnd().
@@ -2761,7 +2762,7 @@ class NewSpace : public Space {
   // different when we cross a page boundary or reset the space.
   void InlineAllocationStep(Address top, Address new_top, Address soon_object,
                             size_t size);
-  void StartNextInlineAllocationStep();
+  void StartNextInlineAllocationStep() override;
 
   friend class SemiSpaceIterator;
 };

src/profiler/sampling-heap-profiler.h

@@ -172,8 +172,11 @@ class SamplingAllocationObserver : public AllocationObserver {
   void Step(int bytes_allocated, Address soon_object, size_t size) override {
     USE(heap_);
     DCHECK(heap_->gc_state() == Heap::NOT_IN_GC);
-    DCHECK(soon_object);
-    profiler_->SampleObject(soon_object, size);
+    if (soon_object) {
+      // TODO(ofrobots): it would be better to sample the next object rather
+      // than skipping this sample epoch if soon_object happens to be null.
+      profiler_->SampleObject(soon_object, size);
+    }
   }
 
   intptr_t GetNextStepSize() override { return GetNextSampleInterval(rate_); }

test/cctest/heap/heap-utils.cc

@@ -32,6 +32,7 @@ int FixedArrayLenFromSize(int size) {
 
 std::vector<Handle<FixedArray>> FillOldSpacePageWithFixedArrays(Heap* heap,
                                                                 int remainder) {
+  PauseAllocationObserversScope pause_observers(heap);
   std::vector<Handle<FixedArray>> handles;
   Isolate* isolate = heap->isolate();
   const int kArraySize = 128;
@@ -203,7 +204,7 @@ void ForceEvacuationCandidate(Page* page) {
     int remaining = static_cast<int>(limit - top);
     space->heap()->CreateFillerObjectAt(top, remaining,
                                         ClearRecordedSlots::kNo);
-    space->SetTopAndLimit(nullptr, nullptr);
+    space->EmptyAllocationInfo();
   }
 }
 

test/cctest/heap/test-invalidated-slots.cc

@@ -20,6 +20,7 @@ namespace heap {
 
 Page* HeapTester::AllocateByteArraysOnPage(
     Heap* heap, std::vector<ByteArray*>* byte_arrays) {
+  PauseAllocationObserversScope pause_observers(heap);
   const int kLength = 256 - ByteArray::kHeaderSize;
   const int kSize = ByteArray::SizeFor(kLength);
   CHECK_EQ(kSize, 256);

test/cctest/test-heap-profiler.cc

@@ -3063,3 +3063,77 @@ TEST(SamplingHeapProfilerLeftTrimming) {
 
   heap_profiler->StopSamplingHeapProfiler();
 }
+
+TEST(SamplingHeapProfilerPretenuredInlineAllocations) {
+  i::FLAG_allow_natives_syntax = true;
+  i::FLAG_expose_gc = true;
+
+  CcTest::InitializeVM();
+  if (!CcTest::i_isolate()->use_optimizer() || i::FLAG_always_opt) return;
+  if (i::FLAG_gc_global || i::FLAG_stress_compaction ||
+      i::FLAG_stress_incremental_marking) {
+    return;
+  }
+
+  v8::HandleScope scope(v8::Isolate::GetCurrent());
+  LocalContext env;
+  v8::HeapProfiler* heap_profiler = env->GetIsolate()->GetHeapProfiler();
+
+  // Suppress randomness to avoid flakiness in tests.
+  v8::internal::FLAG_sampling_heap_profiler_suppress_randomness = true;
+
+  // Grow new space unitl maximum capacity reached.
+  while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
+    CcTest::heap()->new_space()->Grow();
+  }
+
+  i::ScopedVector<char> source(1024);
+  i::SNPrintF(source,
+              "var number_elements = %d;"
+              "var elements = new Array(number_elements);"
+              "function f() {"
+              "  for (var i = 0; i < number_elements; i++) {"
+              "    elements[i] = [{}, {}, {}];"
+              "  }"
+              "  return elements[number_elements - 1];"
+              "};"
+              "f(); gc();"
+              "f(); f();"
+              "%%OptimizeFunctionOnNextCall(f);"
+              "f();"
+              "f;",
+              i::AllocationSite::kPretenureMinimumCreated + 1);
+
+  v8::Local<v8::Function> f =
+      v8::Local<v8::Function>::Cast(CompileRun(source.start()));
+
+  // Make sure the function is producing pre-tenured objects.
+  auto res = f->Call(env.local(), env->Global(), 0, NULL).ToLocalChecked();
+  i::Handle<i::JSObject> o = i::Handle<i::JSObject>::cast(
+      v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
+  CHECK(CcTest::heap()->InOldSpace(o->elements()));
+  CHECK(CcTest::heap()->InOldSpace(*o));
+
+  // Call the function and profile it.
+  heap_profiler->StartSamplingHeapProfiler(64);
+  for (int i = 0; i < 100; ++i) {
+    f->Call(env.local(), env->Global(), 0, NULL).ToLocalChecked();
+  }
+
+  std::unique_ptr<v8::AllocationProfile> profile(
+      heap_profiler->GetAllocationProfile());
+  CHECK(profile);
+  heap_profiler->StopSamplingHeapProfiler();
+
+  const char* names[] = {"f"};
+  auto node_f = FindAllocationProfileNode(env->GetIsolate(), *profile,
+                                          ArrayVector(names));
+  CHECK(node_f);
+
+  int count = 0;
+  for (auto allocation : node_f->allocations) {
+    count += allocation.count;
+  }
+
+  CHECK_GE(count, 9000);
+}