From d8a1c03ff797050b4310bd34b5ef5c0d5c7491e6 Mon Sep 17 00:00:00 2001
From: Yang Shi <yang.shi@linux.alibaba.com>
Date: Wed, 1 Apr 2020 21:10:02 -0700
Subject: [PATCH] mm: vmpressure: use mem_cgroup_is_root API

Use mem_cgroup_is_root() API to check if memcg is root memcg instead of
open coding.

Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/1581398649-125989-2-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/vmpressure.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index 0590f00334489..d69019fc37898 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -280,7 +280,7 @@ void vmpressure(gfp_t gfp, struct mem_cgroup *memcg, bool tree,
 		enum vmpressure_levels level;
 
 		/* For now, no users for root-level efficiency */
-		if (!memcg || memcg == root_mem_cgroup)
+		if (!memcg || mem_cgroup_is_root(memcg))
 			return;
 
 		spin_lock(&vmpr->sr_lock);
-- 
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