diff --git a/include/jemalloc/internal/extent.h b/include/jemalloc/internal/extent.h
index d7db49d4..d6376d5d 100644
--- a/include/jemalloc/internal/extent.h
+++ b/include/jemalloc/internal/extent.h
@@ -77,6 +77,7 @@ rb_proto(, extent_tree_ad_, extent_tree_t, extent_t)
 arena_t	*extent_arena_get(const extent_t *extent);
 void	*extent_addr_get(const extent_t *extent);
 size_t	extent_size_get(const extent_t *extent);
+void	*extent_past_get(const extent_t *extent);
 bool	extent_active_get(const extent_t *extent);
 bool	extent_zeroed_get(const extent_t *extent);
 bool	extent_committed_get(const extent_t *extent);
@@ -119,6 +120,13 @@ extent_size_get(const extent_t *extent)
 	return (extent->e_size);
 }
 
+JEMALLOC_INLINE void *
+extent_past_get(const extent_t *extent)
+{
+
+	return ((void *)(uintptr_t)extent->e_addr + extent->e_size);
+}
+
 JEMALLOC_INLINE bool
 extent_active_get(const extent_t *extent)
 {
diff --git a/include/jemalloc/internal/private_symbols.txt b/include/jemalloc/internal/private_symbols.txt
index 23c206bc..f81cecc3 100644
--- a/include/jemalloc/internal/private_symbols.txt
+++ b/include/jemalloc/internal/private_symbols.txt
@@ -216,6 +216,7 @@ extent_committed_set
 extent_dirty_insert
 extent_dirty_remove
 extent_init
+extent_past_get
 extent_prof_tctx_get
 extent_prof_tctx_set
 extent_size_get