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From: Xiu Jianfeng <xiujianfeng@huawei.com>
To: <hannes@cmpxchg.org>, <mhocko@kernel.org>, <roman.gushchin@linux.dev>,
	<shakeel.butt@linux.dev>, <muchun.song@linux.dev>,
	<akpm@linux-foundation.org>
CC: <cgroups@vger.kernel.org>, <linux-mm@kvack.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH -next] memcg: don't handle event_list for v2 when offlining
Date: Tue, 14 May 2024 13:11:06 +0000
Message-ID: <20240514131106.1326323-1-xiujianfeng@huawei.com>
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The event_list for memcg is only valid for v1 and not used for v2,
so it's unnessesary to handle event_list for v2.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
---
 mm/memcontrol.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d127c9c5fabf..4254f9cd05f4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5881,12 +5881,14 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
 	 * Notify userspace about cgroup removing only after rmdir of cgroup
 	 * directory to avoid race between userspace and kernelspace.
 	 */
-	spin_lock_irq(&memcg->event_list_lock);
-	list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
-		list_del_init(&event->list);
-		schedule_work(&event->remove);
+	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
+		spin_lock_irq(&memcg->event_list_lock);
+		list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
+			list_del_init(&event->list);
+			schedule_work(&event->remove);
+		}
+		spin_unlock_irq(&memcg->event_list_lock);
 	}
-	spin_unlock_irq(&memcg->event_list_lock);
 
 	page_counter_set_min(&memcg->memory, 0);
 	page_counter_set_low(&memcg->memory, 0);
-- 
2.34.1