As a last resort try to allocate out of the smaller size size-class in

src/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2100 matching lines @@
 }
 
 
 FreeListNode* FreeListCategory::PickNodeFromList(int *node_size) {
   FreeListNode* node = top_;
 
   if (node == NULL) return NULL;
 
   while (node != NULL &&
          Page::FromAddress(node->address())->IsEvacuationCandidate()) {
-    available_ -= node->Size();
+    available_ -= reinterpret_cast<FreeSpace*>(node)->Size();
     node = node->next();
   }
 
   if (node != NULL) {
     set_top(node->next());
-    *node_size = node->Size();
+    *node_size = reinterpret_cast<FreeSpace*>(node)->Size();
     available_ -= *node_size;
   } else {
     set_top(NULL);
   }
 
   if (top() == NULL) {
     set_end(NULL);
   }
 
   return node;
 }
 
 
+FreeListNode* FreeListCategory::PickNodeFromList(int size_in_bytes,
+                                                 int *node_size) {
+  FreeListNode* node = PickNodeFromList(node_size);
+  if (node != NULL && *node_size < size_in_bytes) {
+    Free(node, *node_size);
+    *node_size = 0;
+    return NULL;
+  }
+  return node;
+}
+
+
 void FreeListCategory::Free(FreeListNode* node, int size_in_bytes) {
   node->set_next(top_);
   top_ = node;
   if (end_ == NULL) {
     end_ = node;
   }
   available_ += size_in_bytes;
 }
 
 
@@ skipping 44 matching lines @@
 
   // Early return to drop too-small blocks on the floor.
   if (size_in_bytes < kSmallListMin) {
     page->add_non_available_small_blocks(size_in_bytes);
     return size_in_bytes;
   }
 
   // Insert other blocks at the head of a free list of the appropriate
   // magnitude.
   if (size_in_bytes <= kSmallListMax) {
-    ASSERT(!owner_->ConstantAllocationSize() ||
-        (owner_->identity() == MAP_SPACE && size_in_bytes >= Map::kSize) ||
-        (owner_->identity() == CELL_SPACE && size_in_bytes >= Cell::kSize) ||
-        (owner_->identity() == PROPERTY_CELL_SPACE &&
-            size_in_bytes >= JSGlobalPropertyCell::kSize));
     small_list_.Free(node, size_in_bytes);
     page->add_available_in_small_free_list(size_in_bytes);
   } else if (size_in_bytes <= kMediumListMax) {
     medium_list_.Free(node, size_in_bytes);
     page->add_available_in_medium_free_list(size_in_bytes);
   } else if (size_in_bytes <= kLargeListMax) {
     large_list_.Free(node, size_in_bytes);
     page->add_available_in_large_free_list(size_in_bytes);
   } else {
     huge_list_.Free(node, size_in_bytes);
     page->add_available_in_huge_free_list(size_in_bytes);
   }
 
   ASSERT(IsVeryLong() || available() == SumFreeLists());
   return 0;
 }
 
 
 FreeListNode* FreeList::FindNodeFor(int size_in_bytes, int* node_size) {
   FreeListNode* node = NULL;
   Page* page = NULL;
 
-  if ((owner_->ConstantAllocationSize() && size_in_bytes <= kSmallListMax) ||
-      size_in_bytes <= kSmallAllocationMax) {
+  if (size_in_bytes <= kSmallAllocationMax) {
     node = small_list_.PickNodeFromList(node_size);
     if (node != NULL) {
       ASSERT(size_in_bytes <= *node_size);
       page = Page::FromAddress(node->address());
       page->add_available_in_small_free_list(-(*node_size));
+      ASSERT(IsVeryLong() || available() == SumFreeLists());
       return node;
     }
   }
 
   if (size_in_bytes <= kMediumAllocationMax) {
     node = medium_list_.PickNodeFromList(node_size);
     if (node != NULL) {
       ASSERT(size_in_bytes <= *node_size);
       page = Page::FromAddress(node->address());
       page->add_available_in_medium_free_list(-(*node_size));
+      ASSERT(IsVeryLong() || available() == SumFreeLists());
       return node;
     }
   }
 
   if (size_in_bytes <= kLargeAllocationMax) {
     node = large_list_.PickNodeFromList(node_size);
     if (node != NULL) {
       ASSERT(size_in_bytes <= *node_size);
       page = Page::FromAddress(node->address());
       page->add_available_in_large_free_list(-(*node_size));
+      ASSERT(IsVeryLong() || available() == SumFreeLists());
       return node;
     }
   }
 
   int huge_list_available = huge_list_.available();
   for (FreeListNode** cur = huge_list_.GetTopAddress();
        *cur != NULL;
        cur = (*cur)->next_address()) {
     FreeListNode* cur_node = *cur;
     while (cur_node != NULL &&
@@ skipping 22 matching lines @@
       huge_list_available -= size;
       page = Page::FromAddress(node->address());
       page->add_available_in_huge_free_list(-size);
       break;
     }
   }
 
   if (huge_list_.top() == NULL) {
     huge_list_.set_end(NULL);
   }
+  huge_list_.set_available(huge_list_available);
 
-  huge_list_.set_available(huge_list_available);
+  if (node != NULL) {
+    ASSERT(IsVeryLong() || available() == SumFreeLists());
+    return node;
+  }
+
+  if (size_in_bytes <= kSmallListMax) {
+    node = small_list_.PickNodeFromList(size_in_bytes, node_size);
+    if (node != NULL) {
+      ASSERT(size_in_bytes <= *node_size);
+      page = Page::FromAddress(node->address());
+      page->add_available_in_small_free_list(-(*node_size));
+    }
+  } else if (size_in_bytes <= kMediumListMax) {
+    node = medium_list_.PickNodeFromList(size_in_bytes, node_size);
+    if (node != NULL) {
+      ASSERT(size_in_bytes <= *node_size);
+      page = Page::FromAddress(node->address());
+      page->add_available_in_medium_free_list(-(*node_size));
+    }
+  } else if (size_in_bytes <= kLargeListMax) {
+    node = large_list_.PickNodeFromList(size_in_bytes, node_size);
+    if (node != NULL) {
+      ASSERT(size_in_bytes <= *node_size);
+      page = Page::FromAddress(node->address());
+      page->add_available_in_large_free_list(-(*node_size));
+    }
+  }
+
   ASSERT(IsVeryLong() || available() == SumFreeLists());
-
   return node;
 }
 
 
 // Allocation on the old space free list.  If it succeeds then a new linear
 // allocation space has been set up with the top and limit of the space.  If
 // the allocation fails then NULL is returned, and the caller can perform a GC
 // or allocate a new page before retrying.
 HeapObject* FreeList::Allocate(int size_in_bytes) {
   ASSERT(0 < size_in_bytes);
@@ skipping 883 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal