diff --git a/util/mmap.hh b/util/mmap.hh
index cd35eff..a8f8f43 100644
--- a/util/mmap.hh
+++ b/util/mmap.hh
@@ -82,6 +82,14 @@ class scoped_memory {
       : data_(from.data_), size_(from.size_), source_(from.source_) {
       from.steal();
     }
+
+    scoped_memory &operator=(scoped_memory &&from) noexcept {
+      reset();
+      size_ = from.size_;
+      source_ = from.source_;
+      data_ = from.steal();
+      return *this;
+    }
 #endif
 
     ~scoped_memory() { reset(); }
diff --git a/util/probing_hash_table.hh b/util/probing_hash_table.hh
index c1965b4..eae3f78 100644
--- a/util/probing_hash_table.hh
+++ b/util/probing_hash_table.hh
@@ -393,10 +393,19 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
       return backend_.RawEnd();
     }
 
+    void Reserve(size_t capacity) {
+      while (threshold_ < capacity)
+        Double();
+    }
+
   private:
     void DoubleIfNeeded() {
       if (UTIL_LIKELY(Size() < threshold_))
         return;
+      Double();
+    }
+
+    void Double() {
       HugeRealloc(backend_.DoubleTo(), KeyIsRawZero(backend_.invalid_), mem_);
       allocated_ = backend_.DoubleTo();
       backend_.Double(mem_.get(), !KeyIsRawZero(backend_.invalid_));