[heap] Clear wasted_memory_ counter right before sweeping a page.

Bug: v8:9093
Change-Id: I1172f7de24683aea05648f5c6fe1ab3d0dad6655
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1585724
Auto-Submit: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61033}

src/heap/spaces.cc

@@ -697,7 +697,7 @@ Page* PagedSpace::InitializePage(MemoryChunk* chunk, Executability executable) {
                 page->owner()->identity()),
             page->area_size());
   // Make sure that categories are initialized before freeing the area.
-  page->ResetAllocatedBytes();
+  page->ResetAllocationStatistics();
   page->SetOldGenerationPageFlags(heap()->incremental_marking()->IsMarking());
   page->AllocateFreeListCategories();
   page->InitializeFreeListCategories();
@@ -947,7 +947,10 @@ void MemoryChunk::SetYoungGenerationPageFlags(bool is_marking) {
   }
 }
 
-void Page::ResetAllocatedBytes() { allocated_bytes_ = area_size(); }
+void Page::ResetAllocationStatistics() {
+  allocated_bytes_ = area_size();
+  wasted_memory_ = 0;
+}
 
 void Page::AllocateLocalTracker() {
   DCHECK_NULL(local_tracker_);
@@ -958,10 +961,6 @@ bool Page::contains_array_buffers() {
   return local_tracker_ != nullptr && !local_tracker_->IsEmpty();
 }
 
-void Page::ResetFreeListStatistics() {
-  wasted_memory_ = 0;
-}
-
 size_t Page::AvailableInFreeList() {
   size_t sum = 0;
   ForAllFreeListCategories([&sum](FreeListCategory* category) {
@@ -1740,13 +1739,6 @@ int PagedSpace::CountTotalPages() {
   return count;
 }
 
-
-void PagedSpace::ResetFreeListStatistics() {
-  for (Page* page : *this) {
-    page->ResetFreeListStatistics();
-  }
-}
-
 void PagedSpace::SetLinearAllocationArea(Address top, Address limit) {
   SetTopAndLimit(top, limit);
   if (top != kNullAddress && top != limit &&

src/heap/spaces.h

@@ -883,8 +883,6 @@ class Page : public MemoryChunk {
   inline LocalArrayBufferTracker* local_tracker() { return local_tracker_; }
   bool contains_array_buffers();
 
-  void ResetFreeListStatistics();
-
   size_t AvailableInFreeList();
 
   size_t AvailableInFreeListFromAllocatedBytes() {
@@ -909,7 +907,7 @@ class Page : public MemoryChunk {
     allocated_bytes_ -= bytes;
   }
 
-  void ResetAllocatedBytes();
+  void ResetAllocationStatistics();
 
   size_t ShrinkToHighWaterMark();
 
@@ -2146,8 +2144,6 @@ class V8_EXPORT_PRIVATE PagedSpace
   // Approximate amount of physical memory committed for this space.
   size_t CommittedPhysicalMemory() override;
 
-  void ResetFreeListStatistics();
-
   // Sets the capacity, the available space and the wasted space to zero.
   // The stats are rebuilt during sweeping by adding each page to the
   // capacity and the size when it is encountered.  As free spaces are
@@ -2156,7 +2152,6 @@ class V8_EXPORT_PRIVATE PagedSpace
   void ClearStats() {
     accounting_stats_.ClearSize();
     free_list_.ResetStats();
-    ResetFreeListStatistics();
   }
 
   // Available bytes without growing.  These are the bytes on the free list.

src/heap/sweeper.cc

@@ -279,9 +279,10 @@ int Sweeper::RawSweep(Page* p, FreeListRebuildingMode free_list_mode,
   intptr_t max_freed_bytes = 0;
   int curr_region = -1;
 
-  // Set the allocated_bytes counter to area_size. The free operations below
-  // will decrease the counter to actual live bytes.
-  p->ResetAllocatedBytes();
+  // Set the allocated_bytes_ counter to area_size and clear the wasted_memory_
+  // counter. The free operations below will decrease allocated_bytes_ to actual
+  // live bytes and keep track of wasted_memory_.
+  p->ResetAllocationStatistics();
 
   for (auto object_and_size :
        LiveObjectRange<kBlackObjects>(p, marking_state_->bitmap(p))) {