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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9226DC2BA1A for ; Tue, 7 Apr 2020 03:03:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4B0812074F for ; Tue, 7 Apr 2020 03:03:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="M03t/XZn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B0812074F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F12C08E0006; Mon, 6 Apr 2020 23:03:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EC2668E0001; Mon, 6 Apr 2020 23:03:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DD8258E0006; Mon, 6 Apr 2020 23:03:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0218.hostedemail.com [216.40.44.218]) by kanga.kvack.org (Postfix) with ESMTP id C63818E0001 for ; Mon, 6 Apr 2020 23:03:08 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 7BFEB99AD for ; Tue, 7 Apr 2020 03:03:08 +0000 (UTC) X-FDA: 76679562456.30.party35_559ad46884603 X-HE-Tag: party35_559ad46884603 X-Filterd-Recvd-Size: 4014 Received: from mail-il1-f194.google.com (mail-il1-f194.google.com [209.85.166.194]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:03:08 +0000 (UTC) Received: by mail-il1-f194.google.com with SMTP id a6so1779398ilr.4 for ; Mon, 06 Apr 2020 20:03:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=6dPS/ziwlSvonTRptD7myezEgg5T4AMec7Q3+svukcA=; b=M03t/XZnG3RsBSu4ncAY4HWi7/sytfJjkTDXeRkelyebx+4Q2zM1M7R7xocbppPThF sZbQKpep10Tyn1A3a3Y1Qv8+4nQPjn39tG/0Aygnf67PTRj743oJDrBsqhPumdfvhJTC /O1B5ZloZEunKUQetiKPxrnp965wY+QXPobRG58VVf2VukqOW1BljIBLixGPvlsSWnc1 ogDb2oMANKxLyuJ+r1jJ1etERzsrBulEUcR5nPo+toSYqHPqqk3uG11yjiIB/5gkpjab CYjTXsYIyZUeH9pyKHJLiJaaXL7xqs1kufIPV0v+8rqYWuH0vyWcUQevza2XS0tD1cRL IeHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=6dPS/ziwlSvonTRptD7myezEgg5T4AMec7Q3+svukcA=; b=d8keQJyJxDDuqZgesl1OyEyG6jwWIVv8Ez8/au1IhhePFuo4jCQu8WJazwJnqJkqPU Z23kKBKBvs+3afRx03V5NQJHAuRo/T4MYCLys1jm5HRMVCk9b5LDD5f6ahUUQoCelwha 6FETjxtHB1whCtavHBL3tJqaX7/2X/pka+Nkkec4TTuBtB8MXQUNfM3v7DBXDXyXy+3E sFlA0Hn4bfuALYeYZOSEtnY/XZOcXzAuMIoP8jS78/oEfdFrM3pu28fEJZx8nfc9heIk MzSih6bYuUxCfjhCUhXHDUvwEmfdDzQDg5JfoZ8YLFEfYE7/MBjmSZVq44c6bBqz8ySz FKfA== X-Gm-Message-State: AGi0PuaTQGsGj14ULM0fVYWZYL82W68csXqyDfOnjs7Z0ugKMuX0kG8T amWwlc6VmurJRC8zak9AqfpSfGjIiWZrGtyX9jQ= X-Google-Smtp-Source: APiQypItbY9as1gQ7OzhhjvYmgV4fW4YSCsNfV39Jf6SiiETHkEFxkSWbHML+u604x3qkEa0Fq5ioOvFy/6YCRpIqY8= X-Received: by 2002:a92:835b:: with SMTP id f88mr260336ild.137.1586228587574; Mon, 06 Apr 2020 20:03:07 -0700 (PDT) MIME-Version: 1.0 References: <1586192163-20099-1-git-send-email-laoar.shao@gmail.com> <20200406162343.6ae4b8f74c74bcb84d026471@linux-foundation.org> In-Reply-To: <20200406162343.6ae4b8f74c74bcb84d026471@linux-foundation.org> From: Yafang Shao Date: Tue, 7 Apr 2020 11:02:31 +0800 Message-ID: Subject: Re: [PATCH v3] mm, memcg: fix error return value of mem_cgroup_css_alloc() To: Andrew Morton Cc: Matthew Wilcox , Johannes Weiner , Michal Hocko , Vladimir Davydov , Linux MM Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Apr 7, 2020 at 7:23 AM Andrew Morton wrote: > > On Tue, 7 Apr 2020 00:56:03 +0800 Yafang Shao wrote: > > > When I run my memcg testcase which creates lots of memcgs, I found > > there're unexpected out of memory logs while there're still enough > > available free memory. The error log is, > > mkdir: cannot create directory 'foo.65533': Cannot allocate memory > > > > The reason is when we try to create more than MEM_CGROUP_ID_MAX memcgs, an > > -ENOMEM errno will be set by mem_cgroup_css_alloc(), but the right errno > > should be -EBUSY "Device or resource busy". That is same with > > memcg_alloc_cache_id(). > > > > As the errno really misled me, we should make it right. After this patch, > > the error log will be, > > mkdir: cannot create directory 'foo.65533': Device or resource busy > > Thanks. > > Was a -stable backport considered? I only backported to our kernel version 4.18, but I'm not sure whether it will apply to -stable or not. Seems this issue is introduced long time ago. I will try to backport it to -stable. Should I try it based on 5.5.y and 5.6.y only ? Or all the LTS kernel versions ? Thanks Yafang