Revert "[heap] Do precise search in free list for new space"

This reverts commit 72d6dc6d.

Reason for revert: UBSan failure in PagedNewSpace: 
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20UBSan/23130/overview

Original change's description:
> [heap] Do precise search in free list for new space
>
> In case the free list fast path fails, do a precise search through the
> precise category for the current allocation.
>
> Bug: v8:12612
> Change-Id: I120e64b0d09b9cf5a776188180d6e6c53c44886b
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3879494
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Omer Katz <omerkatz@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#83096}

Bug: v8:12612
Change-Id: Ife4a41fa835e61a6d9f0f1c254900288b805f41f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3885884
Commit-Queue: Matthias Liedtke <mliedtke@chromium.org>
Owners-Override: Matthias Liedtke <mliedtke@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#83100}

src/heap/free-list.cc

@@ -111,10 +111,6 @@ void FreeListCategory::Relink(FreeList* owner) {
 
 FreeList* FreeList::CreateFreeList() { return new FreeListManyCachedOrigin(); }
 
-FreeList* FreeList::CreateFreeListForNewSpace() {
-  return new FreeListManyCachedOriginForNewSpace();
-}
-
 FreeSpace FreeList::TryFindNodeIn(FreeListCategoryType type,
                                   size_t minimum_size, size_t* node_size) {
   FreeListCategory* category = categories_[type];
@@ -365,14 +361,12 @@ FreeSpace FreeListManyCachedFastPath::Allocate(size_t size_in_bytes,
   // Fast path part 2: searching the medium categories for tiny objects
   if (node.is_null()) {
     if (size_in_bytes <= kTinyObjectMaxSize) {
-      DCHECK_EQ(kFastPathFirstCategory, first_category);
       for (type = next_nonempty_category[kFastPathFallBackTiny];
            type < kFastPathFirstCategory;
            type = next_nonempty_category[type + 1]) {
         node = TryFindNodeIn(type, size_in_bytes, node_size);
         if (!node.is_null()) break;
       }
-      first_category = kFastPathFallBackTiny;
     }
   }
 
@@ -393,41 +387,19 @@ FreeSpace FreeListManyCachedFastPath::Allocate(size_t size_in_bytes,
     }
   }
 
-  if (!node.is_null()) {
-    if (categories_[type] == nullptr) UpdateCacheAfterRemoval(type);
-    Page::FromHeapObject(node)->IncreaseAllocatedBytes(*node_size);
+  // Updating cache
+  if (!node.is_null() && categories_[type] == nullptr) {
+    UpdateCacheAfterRemoval(type);
   }
 
 #ifdef DEBUG
   CheckCacheIntegrity();
 #endif
 
-  DCHECK(IsVeryLong() || Available() == SumFreeLists());
-  return node;
-}
-
-// ------------------------------------------------
-// FreeListManyCachedFastPath implementation
-
-FreeSpace FreeListManyCachedFastPathForNewSpace::Allocate(
-    size_t size_in_bytes, size_t* node_size, AllocationOrigin origin) {
-  FreeSpace node =
-      FreeListManyCachedFastPath::Allocate(size_in_bytes, node_size, origin);
-  if (!node.is_null()) return node;
-
-  // Search through the precise category for a fit
-  FreeListCategoryType type = SelectFreeListCategoryType(size_in_bytes);
-  node = SearchForNodeInList(type, size_in_bytes, node_size);
-
   if (!node.is_null()) {
-    if (categories_[type] == nullptr) UpdateCacheAfterRemoval(type);
     Page::FromHeapObject(node)->IncreaseAllocatedBytes(*node_size);
   }
 
-#ifdef DEBUG
-  CheckCacheIntegrity();
-#endif
-
   DCHECK(IsVeryLong() || Available() == SumFreeLists());
   return node;
 }
@@ -446,19 +418,6 @@ FreeSpace FreeListManyCachedOrigin::Allocate(size_t size_in_bytes,
   }
 }
 
-// ------------------------------------------------
-// FreeListManyCachedOrigin implementation
-
-FreeSpace FreeListManyCachedOriginForNewSpace::Allocate(
-    size_t size_in_bytes, size_t* node_size, AllocationOrigin origin) {
-  if (origin == AllocationOrigin::kGC) {
-    return FreeListManyCached::Allocate(size_in_bytes, node_size, origin);
-  } else {
-    return FreeListManyCachedOriginForNewSpace::Allocate(size_in_bytes,
-                                                         node_size, origin);
-  }
-}
-
 // ------------------------------------------------
 // Generic FreeList methods (non alloc/free related)
 

src/heap/free-list.h

@@ -122,10 +122,8 @@ class FreeListCategory {
 // categories would scatter allocation more.
 class FreeList {
  public:
-  // Creates a Freelist of the default class.
+  // Creates a Freelist of the default class (FreeListLegacy for now).
   V8_EXPORT_PRIVATE static FreeList* CreateFreeList();
-  // Creates a Freelist for new space.
-  V8_EXPORT_PRIVATE static FreeList* CreateFreeListForNewSpace();
 
   virtual ~FreeList() = default;
 
@@ -475,21 +473,6 @@ class V8_EXPORT_PRIVATE FreeListManyCachedFastPath : public FreeListManyCached {
       FreeListManyCachedFastPathSelectFastAllocationFreeListCategoryType);
 };
 
-// Same as FreeListManyCachedFastPath but falls back to a precise search of the
-// precise category in case allocation fails. Because new space is relatively
-// small, the free list is also relatively small and larger categories are more
-// likely to be empty. The precise search is meant to avoid an allocation
-// failure and thus avoid GCs.
-class V8_EXPORT_PRIVATE FreeListManyCachedFastPathForNewSpace
-    : public FreeListManyCachedFastPath {
- public:
-  V8_WARN_UNUSED_RESULT FreeSpace Allocate(size_t size_in_bytes,
-                                           size_t* node_size,
-                                           AllocationOrigin origin) override;
-
- protected:
-};
-
 // Uses FreeListManyCached if in the GC; FreeListManyCachedFastPath otherwise.
 // The reasoning behind this FreeList is the following: the GC runs in
 // parallel, and therefore, more expensive allocations there are less
@@ -506,16 +489,6 @@ class V8_EXPORT_PRIVATE FreeListManyCachedOrigin
                                            AllocationOrigin origin) override;
 };
 
-// Similar to FreeListManyCachedOrigin but uses
-// FreeListManyCachedFastPathForNewSpace for allocations outside the GC.
-class V8_EXPORT_PRIVATE FreeListManyCachedOriginForNewSpace
-    : public FreeListManyCachedFastPathForNewSpace {
- public:
-  V8_WARN_UNUSED_RESULT FreeSpace Allocate(size_t size_in_bytes,
-                                           size_t* node_size,
-                                           AllocationOrigin origin) override;
-};
-
 }  // namespace internal
 }  // namespace v8
 

src/heap/new-spaces.cc

@@ -902,7 +902,7 @@ PagedSpaceForNewSpace::PagedSpaceForNewSpace(
     LinearAllocationArea& allocation_info,
     LinearAreaOriginalData& linear_area_original_data)
     : PagedSpaceBase(heap, NEW_SPACE, NOT_EXECUTABLE,
-                     FreeList::CreateFreeListForNewSpace(), allocation_counter,
+                     FreeList::CreateFreeList(), allocation_counter,
                      allocation_info, linear_area_original_data,
                      CompactionSpaceKind::kNone),
       initial_capacity_(RoundDown(initial_capacity, Page::kPageSize)),