mem_cgroup_is_root() is preferred API to check if memcg is root or not. Use it instead of deferencing css->parent. Cc: Huang Ying <ying.huang@xxxxxxxxx> Cc: Tim Chen <tim.c.chen@xxxxxxxxx> Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> --- include/linux/swap.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index a8f6d5d..8739063 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -623,7 +623,7 @@ static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) return vm_swappiness; /* root ? */ - if (mem_cgroup_disabled() || !memcg->css.parent) + if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) return vm_swappiness; return memcg->swappiness; -- 1.8.3.1
