diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 6d3ed196f6f9..b5eadee0e8f0 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -877,6 +877,22 @@ static int trylock_zspage(struct zspage *zspage)
 	return 0;
 }
 
+/*
+ * Three free helpers, kept apart here:
+ *
+ * __free_zspage_lockless(): bare core; walks zpdescs and returns pages
+ *   to the buddy allocator.  Caller owns all zpdesc locks and has
+ *   removed the zspage from its class list.  Used by zs_free() outside
+ *   class->lock so the buddy-side work does not stall the class.
+ *
+ * __free_zspage(): __free_zspage_lockless() + per-class accounting,
+ *   under class->lock.  Used by async_free_zspage(), the worker for
+ *   zspages whose trylock_zspage() failed.
+ *
+ * free_zspage(): full wrapper - trylock zpdescs, remove from class
+ *   list, call __free_zspage(); kicks deferred free on contention.
+ *   Used by compaction.
+ */
 static inline void __free_zspage_lockless(struct zspage *zspage)
 {
 	struct zpdesc *zpdesc, *next;