diff --git a/deps/v8/src/heap/mark-compact.cc b/deps/v8/src/heap/mark-compact.cc
index 641ac7d1dc96bc..8f214ac1150fef 100644
--- a/deps/v8/src/heap/mark-compact.cc
+++ b/deps/v8/src/heap/mark-compact.cc
@@ -2422,6 +2422,13 @@ void MarkCompactCollector::ClearWeakCollections() {
           table->RemoveEntry(i);
         }
       }
+      // Rehash if more than 25% of the entries are deleted entries.
+      // TODO(jochen): Consider to shrink the fixed array in place.
+      if ((table->NumberOfDeletedElements() << kJSWeakCollectionLoadFactorExp) >
+          table->NumberOfElements()) {
+        HandleScope scope(heap()->isolate());
+        table->Rehash(heap()->isolate()->factory()->undefined_value());
+      }
     }
     weak_collection_obj = weak_collection->next();
     weak_collection->set_next(heap()->undefined_value());
diff --git a/deps/v8/src/heap/mark-compact.h b/deps/v8/src/heap/mark-compact.h
index cc5449f97765e7..296c7142b9cd09 100644
--- a/deps/v8/src/heap/mark-compact.h
+++ b/deps/v8/src/heap/mark-compact.h
@@ -365,6 +365,10 @@ class MarkCompactCollector {
   static const uint32_t kSingleFreeEncoding = 0;
   static const uint32_t kMultiFreeEncoding = 1;
 
+  // If the number of deleted slots in a JSWeakCollection exceeds the number
+  // of entries / 2^(factor), we rehash the table.
+  static const int kJSWeakCollectionLoadFactorExp = 1;
+
   static inline bool IsMarked(Object* obj);
   static bool IsUnmarkedHeapObjectWithHeap(Heap* heap, Object** p);
 
diff --git a/deps/v8/src/objects.cc b/deps/v8/src/objects.cc
index 67a59638318844..4fd51e97ee5d35 100644
--- a/deps/v8/src/objects.cc
+++ b/deps/v8/src/objects.cc
@@ -17347,6 +17347,16 @@ void HashTable<Derived, Shape, Key>::Rehash(Key key) {
       }
     }
   }
+  // Wipe deleted entries.
+  Heap* heap = GetHeap();
+  Object* the_hole = heap->the_hole_value();
+  Object* undefined = heap->undefined_value();
+  for (uint32_t current = 0; current < capacity; current++) {
+    if (get(EntryToIndex(current)) == the_hole) {
+      set(EntryToIndex(current), undefined);
+    }
+  }
+  SetNumberOfDeletedElements(0);
 }
 
 
@@ -18145,6 +18155,7 @@ Handle<CompilationCacheTable> CompilationCacheTable::PutRegExp(
 void CompilationCacheTable::Age() {
   DisallowHeapAllocation no_allocation;
   Object* the_hole_value = GetHeap()->the_hole_value();
+  uint32_t capacity = Capacity();
   for (int entry = 0, size = Capacity(); entry < size; entry++) {
     int entry_index = EntryToIndex(entry);
     int value_index = entry_index + 1;
@@ -18168,6 +18179,16 @@ void CompilationCacheTable::Age() {
       }
     }
   }
+  // Wipe deleted entries.
+  Heap* heap = GetHeap();
+  Object* the_hole = heap->the_hole_value();
+  Object* undefined = heap->undefined_value();
+  for (uint32_t current = 0; current < capacity; current++) {
+    if (get(EntryToIndex(current)) == the_hole) {
+      set(EntryToIndex(current), undefined);
+    }
+  }
+  SetNumberOfDeletedElements(0);
 }
 
 
@@ -18707,6 +18728,12 @@ Handle<ObjectHashTable> ObjectHashTable::Put(Handle<ObjectHashTable> table,
     return table;
   }
 
+  // Rehash if more than 25% of the entries are deleted entries.
+  // TODO(jochen): Consider to shrink the fixed array in place.
+  if ((table->NumberOfDeletedElements() << 1) > table->NumberOfElements()) {
+    table->Rehash(isolate->factory()->undefined_value());
+  }
+
   // Check whether the hash table should be extended.
   table = EnsureCapacity(table, 1, key);
   table->AddEntry(table->FindInsertionEntry(hash), *key, *value);
diff --git a/deps/v8/test/cctest/test-weakmaps.cc b/deps/v8/test/cctest/test-weakmaps.cc
index 781ad1f69f8877..c16bdf5094350a 100644
--- a/deps/v8/test/cctest/test-weakmaps.cc
+++ b/deps/v8/test/cctest/test-weakmaps.cc
@@ -124,7 +124,7 @@ TEST(Weakness) {
   heap->CollectAllGarbage(false);
   CHECK_EQ(1, NumberOfWeakCalls);
   CHECK_EQ(0, ObjectHashTable::cast(weakmap->table())->NumberOfElements());
-  CHECK_EQ(2,
+  CHECK_EQ(0,
            ObjectHashTable::cast(weakmap->table())->NumberOfDeletedElements());
 }
 
diff --git a/deps/v8/test/cctest/test-weaksets.cc b/deps/v8/test/cctest/test-weaksets.cc
index 643bb48ab1aa49..0de63b9228fe52 100644
--- a/deps/v8/test/cctest/test-weaksets.cc
+++ b/deps/v8/test/cctest/test-weaksets.cc
@@ -123,8 +123,8 @@ TEST(WeakSet_Weakness) {
   heap->CollectAllGarbage(false);
   CHECK_EQ(1, NumberOfWeakCalls);
   CHECK_EQ(0, ObjectHashTable::cast(weakset->table())->NumberOfElements());
-  CHECK_EQ(
-      1, ObjectHashTable::cast(weakset->table())->NumberOfDeletedElements());
+  CHECK_EQ(0,
+           ObjectHashTable::cast(weakset->table())->NumberOfDeletedElements());
 }