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

This reverts commit ec952aaa.

Reason for revert: https://bugs.chromium.org/p/chromium/issues/detail?id=767144

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}

TBR=ulan@chromium.org,mlippautz@chromium.org,ofrobots@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:633920
Change-Id: I576cdab4a03f9fe057ebe1bf7da9dfe3c7bf62cd
Reviewed-on: https://chromium-review.googlesource.com/676683Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48098}

src/heap/spaces-inl.h

@@ -369,11 +369,6 @@ AllocationResult PagedSpace::AllocateRawAligned(int size_in_bytes,
 
 AllocationResult PagedSpace::AllocateRaw(int size_in_bytes,
                                          AllocationAlignment alignment) {
-  DCHECK(top() >= top_on_previous_step_);
-  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
@@ -383,13 +378,11 @@ 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) && !is_local()) {
-    AllocationStep(static_cast<int>(size_in_bytes + bytes_since_last),
-                   heap_obj->address(), size_in_bytes);
+  if (!result.IsRetry() && result.To(&heap_obj)) {
+    AllocationStep(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

@@ -1332,7 +1332,6 @@ 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) {
@@ -1340,7 +1339,6 @@ 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; }
@@ -1349,12 +1347,11 @@ void Space::ResumeAllocationObservers() {
   allocation_observers_paused_ = false;
 }
 
-void Space::AllocationStep(int bytes_since_last, Address soon_object,
-                           int size) {
+void Space::AllocationStep(Address soon_object, int size) {
   if (!allocation_observers_paused_) {
     heap()->CreateFillerObjectAt(soon_object, size, ClearRecordedSlots::kNo);
     for (AllocationObserver* observer : allocation_observers_) {
-      observer->AllocationStep(bytes_since_last, soon_object, size);
+      observer->AllocationStep(size, soon_object, size);
     }
   }
 }
@@ -1374,8 +1371,7 @@ PagedSpace::PagedSpace(Heap* heap, AllocationSpace space,
     : Space(heap, space, executable),
       anchor_(this),
       free_list_(this),
-      locked_page_(nullptr),
-      top_on_previous_step_(0) {
+      locked_page_(nullptr) {
   area_size_ = MemoryAllocator::PageAreaSize(space);
   accounting_stats_.Clear();
 
@@ -1604,48 +1600,6 @@ 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();
@@ -1691,12 +1645,6 @@ 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);
@@ -2139,6 +2087,16 @@ 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);
@@ -2147,28 +2105,12 @@ 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(top_on_previous_step_ == 0);
   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) {
@@ -2943,6 +2885,7 @@ 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++) {
@@ -2956,21 +2899,38 @@ 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()));
 
-  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);
+  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);
   }
-  owner_->SetAllocationInfo(start, limit);
-
   return true;
 }
 
@@ -3358,7 +3318,7 @@ AllocationResult LargeObjectSpace::AllocateRaw(int object_size,
   if (heap()->incremental_marking()->black_allocation()) {
     heap()->incremental_marking()->marking_state()->WhiteToBlack(object);
   }
-  AllocationStep(object_size, object->address(), object_size);
+  AllocationStep(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_; }
 
-  void AddAllocationObserver(AllocationObserver* observer);
+  V8_EXPORT_PRIVATE virtual void AddAllocationObserver(
+      AllocationObserver* observer);
 
-  void RemoveAllocationObserver(AllocationObserver* observer);
+  V8_EXPORT_PRIVATE virtual void RemoveAllocationObserver(
+      AllocationObserver* observer);
 
   V8_EXPORT_PRIVATE virtual void PauseAllocationObservers();
 
   V8_EXPORT_PRIVATE virtual void ResumeAllocationObservers();
 
-  V8_EXPORT_PRIVATE virtual void StartNextInlineAllocationStep() {}
-
-  void AllocationStep(int bytes_since_last, Address soon_object, int size);
+  void AllocationStep(Address soon_object, int size);
 
   // Return the total amount committed memory for this space, i.e., allocatable
   // memory and page headers.
@@ -2071,8 +2071,15 @@ class V8_EXPORT_PRIVATE PagedSpace : NON_EXPORTED_BASE(public Space) {
 
   void ResetFreeList() { free_list_.Reset(); }
 
-  void PauseAllocationObservers() override;
-  void ResumeAllocationObservers() override;
+  // 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);
 
   // Empty space allocation info, returning unused area to free list.
   void EmptyAllocationInfo();
@@ -2177,21 +2184,6 @@ 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.
@@ -2254,7 +2246,6 @@ 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;
@@ -2656,6 +2647,14 @@ 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().
@@ -2763,7 +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() override;
+  void StartNextInlineAllocationStep();
 
   friend class SemiSpaceIterator;
 };

src/profiler/sampling-heap-profiler.h

@@ -172,11 +172,8 @@ 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);
-    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);
-    }
+    DCHECK(soon_object);
+    profiler_->SampleObject(soon_object, size);
   }
 
   intptr_t GetNextStepSize() override { return GetNextSampleInterval(rate_); }

test/cctest/heap/heap-utils.cc

@@ -32,7 +32,6 @@ 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;
@@ -204,7 +203,7 @@ void ForceEvacuationCandidate(Page* page) {
     int remaining = static_cast<int>(limit - top);
     space->heap()->CreateFillerObjectAt(top, remaining,
                                         ClearRecordedSlots::kNo);
-    space->EmptyAllocationInfo();
+    space->SetTopAndLimit(nullptr, nullptr);
   }
 }
 

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

@@ -20,7 +20,6 @@ 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

@@ -3063,77 +3063,3 @@ 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);
-}