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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 E177EC2BA1A for ; Mon, 6 Apr 2020 23:23:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9AD1620753 for ; Mon, 6 Apr 2020 23:23:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="c0n+wrAP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9AD1620753 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3D51F8E0005; Mon, 6 Apr 2020 19:23:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3ACAF8E0001; Mon, 6 Apr 2020 19:23:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2E9D38E0005; Mon, 6 Apr 2020 19:23:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0239.hostedemail.com [216.40.44.239]) by kanga.kvack.org (Postfix) with ESMTP id 16F778E0001 for ; Mon, 6 Apr 2020 19:23:46 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id C07F8181AEF10 for ; Mon, 6 Apr 2020 23:23:45 +0000 (UTC) X-FDA: 76679009610.14.boat65_3deb5bee5365e X-HE-Tag: boat65_3deb5bee5365e X-Filterd-Recvd-Size: 2380 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Mon, 6 Apr 2020 23:23:45 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4FD8920753; Mon, 6 Apr 2020 23:23:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586215424; bh=yhaUG1HDb58BHGcPv4dsuYrxksCS3n0SOhlGn2CF/SU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=c0n+wrAPuImnzL5y8+c1ZPTGEqcamGt4BDVl8Dia8nO9s9efZhwv5RAivONpQC7xD RK3n117z9zfG48ugIdpO/IQNhDbrglS5RyjzEPT0GAy4g3w/LsDZMEl/iBQONE1Zz9 5gj9/SPidce4kiMn5aOLedC5yfGK5AtVQr2LdR/I= Date: Mon, 6 Apr 2020 16:23:43 -0700 From: Andrew Morton To: Yafang Shao Cc: willy@infradead.org, hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com, linux-mm@kvack.org Subject: Re: [PATCH v3] mm, memcg: fix error return value of mem_cgroup_css_alloc() Message-Id: <20200406162343.6ae4b8f74c74bcb84d026471@linux-foundation.org> In-Reply-To: <1586192163-20099-1-git-send-email-laoar.shao@gmail.com> References: <1586192163-20099-1-git-send-email-laoar.shao@gmail.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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, 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?