From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 854E9CA0EE0 for ; Fri, 30 Aug 2024 05:45:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F1D4E6B00AC; Fri, 30 Aug 2024 01:45:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EA5C36B00BF; Fri, 30 Aug 2024 01:45:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D45ED6B00C0; Fri, 30 Aug 2024 01:45:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id AF48F6B00AC for ; Fri, 30 Aug 2024 01:45:31 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 5BC454149F for ; Fri, 30 Aug 2024 05:45:31 +0000 (UTC) X-FDA: 82507824462.30.48860A6 Received: from cmccmta1.chinamobile.com (cmccmta8.chinamobile.com [111.22.67.151]) by imf30.hostedemail.com (Postfix) with ESMTP id E1C2880007 for ; Fri, 30 Aug 2024 05:45:27 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=none; spf=pass (imf30.hostedemail.com: domain of liujing@cmss.chinamobile.com designates 111.22.67.151 as permitted sender) smtp.mailfrom=liujing@cmss.chinamobile.com; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724996684; a=rsa-sha256; cv=none; b=4P+s90Mcq8MrxMS/191EyEkC8ixkbSmDvrIu3g3DyGbtsfBbK35FY2/HhFBcrzYWG2vb+Q ERfwhv94MaiMukUbvf5Py8qrDMQ70niJQY0bwH+TU8YiXRcnDAAx+bIJE5Oubru/p4uU// 0IueLwV7YeBGzAKTeLr4YxqhchpbVb4= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=none; spf=pass (imf30.hostedemail.com: domain of liujing@cmss.chinamobile.com designates 111.22.67.151 as permitted sender) smtp.mailfrom=liujing@cmss.chinamobile.com; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724996684; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references; bh=n0SJOAawgEYlbbY9S+hqvRlmE3k9GTwaQCyEv71fGJM=; b=8Jxb5plqffbL2N2VDSDKqfnXnbWM96mrGEimT8kPfK6J5y2fjBs3zwlxtPQQqf5p1m4acj iu+Z53VF3MNgJl0PwLb3eCZ3AZWGw3z4aKGvJz//B3Qa1yI9rrkEpvtMLd2FA/QWupsWHr /SlVjNiTchu2nUDLhT6u915D+vXMyF4= X-RM-TagInfo: emlType=0 X-RM-SPAM-FLAG:00000000 Received:from spf.mail.chinamobile.com (unknown[10.188.0.87]) by rmmx-syy-dmz-app02-12002 (RichMail) with SMTP id 2ee266d15c72839-f2840; Fri, 30 Aug 2024 13:45:24 +0800 (CST) X-RM-TRANSID:2ee266d15c72839-f2840 X-RM-TagInfo: emlType=0 X-RM-SPAM-FLAG:00000000 Received:from localhost.localdomain.localdomain (unknown[10.54.5.255]) by rmsmtp-syy-appsvr07-12007 (RichMail) with SMTP id 2ee766d15c73443-cce58; Fri, 30 Aug 2024 13:45:24 +0800 (CST) X-RM-TRANSID:2ee766d15c73443-cce58 From: Liu Jing To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Liu Jing Subject: The percpu memory used by memcg cannot be cleared Date: Fri, 30 Aug 2024 01:06:44 +0800 Message-Id: <20240829170644.15588-1-liujing@cmss.chinamobile.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Stat-Signature: 11w53ntixtcedhtm3b4bdjxqefnhaqkm X-Rspamd-Queue-Id: E1C2880007 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1724996727-187157 X-HE-Meta: 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 foVJQOfj 1jxD8KNjLXZf4VHjV+lNSckTJWB82yfoYWpY9 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: hello=EF=BC=8Clinux boss=0D =0D I found a problem in the process of using linux memcg=EF=BC=8CWhen = I turned swap off, the memcg memory I created with the following script cou= ld not be deleted with echo 0 > memory.force_empty, as explained below=E3= =80=82=0D =0D ---------------------------------------------------------------------------= -------------------------------=0D step1=EF=BC=9Aswapoff -a=0D =0D =0D step2=EF=BC=9Ause this script to create memcg=0D =0D #!/bin/bash=0D mkdir -p /tmp/test=0D for i in 'seq 2000'=0D do=0D sudo mkdir -p /sys/fs/cgroup/memory/user.slice/user-0.slice/test$ {= i}=0D sudo echo $$ > /sys/fs/cgroup/memory/user.slice/user-0.slice/test$ = {i}/tasks=0D sudo echo 'data' > /tmp/test/test$ {i}=0D sudo echo $$ > /sys/fs/cgroup/memory/user.slice/user-0.slice/tasks= =0D sudo rmdir /sys/fs/cgroup/memory/user.slice/user-0.slice/test$ {i}= =0D done=0D =0D =0D step3=EF=BC=9Aview /proc/cgroup and /proc/meminfo files=0D =0D [root@localhost ~]# cat /proc/cgroups=0D #subsys_name hierarchy num_cgroups enabled=0D cpuset 10 1 1=0D cpu 4 1 1=0D cpuacct 4 1 1=0D blkio 13 1 1=0D memory 14 2009 1=0D devices 6 94 1=0D =0D [root@localhost ~]# cat /proc/meminfo | grep Percpu=0D Percpu: 600576 kB=0D =0D =0D step4=EF=BC=9Awhen I use "echo 0 > /sys/fs/cgroup/memory/user.slice/user-0.= slice/memory.force_empty", I find the num_cgroups of memory and percpu hav= e no changed=0D =0D [root@localhost ~]# echo 0 > /sys/fs/cgroup/memory/user.slice/user-0.slice/= memory.force_empty=0D [root@localhost ~]# cat /proc/cgroups=0D #subsys_name hierarchy num_cgroups enabled=0D cpuset 10 1 1=0D cpu 4 1 1=0D cpuacct 4 1 1=0D blkio 13 1 1=0D memory 14 2039 1=0D devices 6 87 1=0D =0D [root@localhost ~]# cat /proc/meminfo | grep Percpu=0D Percpu: 600576 kB=0D =0D =0D step 5: when I use swapon -a to open swap, then echo 0 > /sys/fs/cgroup/mem= ory/user.slice/user-0.slice/memory.force_empty again=0D =0D [root@localhost ~]# swapon -a=0D [root@localhost ~]# echo 0 > /sys/fs/cgroup/memory/user.slice/user-0.slice/= memory.force_empty=0D =0D =0D step 6: view /proc/cgroup and /proc/meminfo files ,I found the the num_cgr= oups of memory and percpu have been reduced. =0D [root@localhost ~]# cat /proc/cgroups=0D #subsys_name hierarchy num_cgroups enabled=0D cpuset 10 1 1=0D cpu 4 1 1=0D cpuacct 4 1 1=0D blkio 13 1 1=0D memory 14 185 1=0D devices 6 87 1=0D freezer 9 1 1=0D =0D [root@localhost ~]# cat /proc/meminfo | grep Percpu=0D Percpu: 120832 kB=0D ---------------------------------------------------------------------------= -----------------------------=0D =0D =0D Therefore, I want to know why swap affects memcg memory reclamation, echo = 0 > memory.force_empty this interface should force the memory used by the c= group to be reclaimed. =0D I want to know why ,I look forward to hearing back from the community.=0D Thanks.=0D