1 files changed, 13 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1ff552e3722b..bcb38718e174 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5748,6 +5748,19 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry)
 	rcu_read_unlock();
 }
 
+long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
+{
+	long nr_swap_pages = get_nr_swap_pages();
+
+	if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
+		return nr_swap_pages;
+	for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
+		nr_swap_pages = min_t(long, nr_swap_pages,
+				      READ_ONCE(memcg->swap.limit) -
+				      page_counter_read(&memcg->swap));
+	return nr_swap_pages;
+}
+
 /* for remember boot option*/
 #ifdef CONFIG_MEMCG_SWAP_ENABLED
 static int really_do_swap_account __initdata = 1;