fix up freelist stats naming and add FreeAlloc

db.go

@@ -557,8 +557,9 @@ func (db *DB) allocate(count int) (*page, error) {
 // Stats represents statistics about the database.
 type Stats struct {
 	// Freelist stats
-	FreelistN     int // total number of pages on the freelist
-	FreelistAlloc int // total bytes used by the freelist and the pages on it
+	FreePageN     int // total number of free pages
+	FreeAlloc     int // total bytes allocated in free pages
+	FreelistInuse int // total bytes used by the freelist
 
 	// Transaction stats
 	TxN     int // total number of started read transactions

db_test.go

@@ -254,7 +254,7 @@ func TestDB_Stats(t *testing.T) {
 		})
 		stats := db.Stats()
 		assert.Equal(t, 2, stats.TxStats.PageCount, "PageCount")
-		assert.Equal(t, 2, stats.FreelistN, "FreelistN %d", db.freelist.count())
+		assert.Equal(t, 2, stats.FreePageN, "FreelistN")
 	})
 }
 

tx.go

@@ -241,8 +241,9 @@ func (tx *Tx) close() {
 
 		// Merge statistics.
 		tx.db.statlock.Lock()
-		tx.db.stats.FreelistN = freelistN
-		tx.db.stats.FreelistAlloc = freelistAlloc
+		tx.db.stats.FreePageN = freelistN
+		tx.db.stats.FreeAlloc = freelistN * tx.db.pageSize
+		tx.db.stats.FreelistInuse = freelistAlloc
 		tx.db.stats.TxStats.add(&tx.stats)
 		tx.db.statlock.Unlock()
 	} else {