Redundant copy cleanup (NFC)

storage/innobase/fsp/fsp0space.cc

@@ -210,7 +210,7 @@ dberr_t Tablespace::add_datafile(const char *filepath)
 
 	/* Now add a new Datafile and set the filepath
 	using the m_path created above. */
-	m_files.push_back(Datafile(m_flags, FIL_IBD_FILE_INITIAL_SIZE, 0));
+	m_files.emplace_back(m_flags, FIL_IBD_FILE_INITIAL_SIZE, 0);
 	m_files.back().make_filepath(m_path, {basename, strlen(basename) - 4},
 				     IBD);
 

storage/innobase/fsp/fsp0sysspace.cc

@@ -288,7 +288,7 @@ SysTablespace::parse_params(
 			}
 		}
 
-		m_files.push_back(Datafile(flags(), uint32_t(size), order));
+		m_files.emplace_back(flags(), uint32_t(size), order);
 		m_files.back().make_filepath(path(),
 					     {filepath, strlen(filepath)},
 					     NO_EXT);

storage/innobase/trx/trx0purge.cc

@@ -1326,7 +1326,7 @@ void purge_sys_t::batch_cleanup(const purge_sys_t::iterator &head)
   m_active= false;
 
   /* Release the undo pages. */
-  for (auto p : pages)
+  for (auto &p : pages)
     p.second->unfix();
   pages.clear();
   pages.reserve(srv_purge_batch_size);

tpool/tpool_structs.h

@@ -245,19 +245,16 @@ template <typename T> class circular_queue
     if (new_size <= current_size)
       return;
     size_t new_capacity = new_size - 1;
-    std::vector<T> new_buffer(new_capacity);
-    /* Figure out faster way to copy*/
-    size_t i = 0;
-    while (!empty())
+    size_t const old_size = m_buffer.size();
+    m_buffer.resize(new_capacity);
+    if (m_head < m_tail) 
     {
-      T& ele = front();
-      pop();
-      new_buffer[i++] = ele;
-    }
-    m_buffer = new_buffer;
+      for (size_t i = new_capacity - 1, j = old_size - 1; m_tail <= j; --i, --j)
+        std::swap(m_buffer[i], m_buffer[j]);
+      m_tail = m_tail + (m_buffer.size() - old_size);
+    }    
     m_capacity = new_capacity;
-    m_tail = 0;
-    m_head = current_size;
+    assert(size() == current_size);
   }
   void push(T ele)
   {