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=-15.9 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 467B0CA9ED0 for ; Sat, 2 Nov 2019 23:55:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B721215EA for ; Sat, 2 Nov 2019 23:55:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Y0grKuDc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727386AbfKBXzl (ORCPT ); Sat, 2 Nov 2019 19:55:41 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:40923 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726689AbfKBXzl (ORCPT ); Sat, 2 Nov 2019 19:55:41 -0400 Received: by mail-pl1-f194.google.com with SMTP id e3so3859940plt.7 for ; Sat, 02 Nov 2019 16:55:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=z0bgko71g/IEmBKD3Kro6mR4U+O8GKl/Z/Ms7dBzsH4=; b=Y0grKuDcaYtkpumf209OEt0taRJ7Y6eOtn7rvFJPq1VMFZ+BoXqfMZNRq9rLCrW12u D8VNlbfWEqIKt3A1Wl+k1SxaU9X2kXhZXXesNApA/aYan2qyIkNS8pgyMMfIvkD0w4VS U6msNXpe1KK9KZZGIiGmJNMpwNFaKC+VtlKzW5GbBSjRIjnen7Tk66LtCmd6uh5QJN6G 8oIubEqXAwVIFxaXfQiQrJEYD0VQHXDkafpol8yjZhyMnR0FWJGrB2uvS0BHdLFhgof7 K7QbS5Styk3SYEeVaUYq45g2bzeTAhcNl2Lg/i35OjWCROKCu7YX5GPeBPv+2Rq222E3 dl9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=z0bgko71g/IEmBKD3Kro6mR4U+O8GKl/Z/Ms7dBzsH4=; b=WRkQf5ZbkQzSnrU+2fO1RP0i4QaqAkIIU+fruhDFUGPUYwtlfAKezype+gvAU5A1ev PMXZimIfK15Dj6aRI9b8vDCB60uT2oyK+cu0nJjlBb1iV0HPYjBf2JG2MYfrJcXjgZB4 0Vl0TES7RQI2+7TlS+i5ufxvQTwAMSbpRPSYN7LXa/1axQAeihuLrw4VG+vrsIK3mVpn Yb5es9mrxTXzmHRX/3V5U25ECKJLIcwM8sc3OjynquiArRyn1SFfjfGQdvWd9IoDEj3Y j/gOVUoe4sukea75+mTCv3HjaEmr5/gFTa7e+Ylp8Mcix4ZY9ttmQNWeePwXMPg1cgC4 SvVg== X-Gm-Message-State: APjAAAU2DMg6u/lyNcb0wI9YzP+HpgclgphRqLK4C9HInQ8cSdKs6d5Z HPZjTaN5XRfsLvQpvJuCk/gS8w== X-Google-Smtp-Source: APXvYqw7xUJMFwKAO6VdFjMCpsRiabe8H2rE/jwkyhOUOIw7HwwCAPhxRAcxaZmTJgrYrlWPCCdchQ== X-Received: by 2002:a17:902:6909:: with SMTP id j9mr19271681plk.276.1572738938992; Sat, 02 Nov 2019 16:55:38 -0700 (PDT) Received: from [2620:15c:17:3:3a5:23a7:5e32:4598] ([2620:15c:17:3:3a5:23a7:5e32:4598]) by smtp.gmail.com with ESMTPSA id c66sm11767706pfb.25.2019.11.02.16.55.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 02 Nov 2019 16:55:38 -0700 (PDT) Date: Sat, 2 Nov 2019 16:55:37 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Konstantin Khlebnikov cc: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Michal Hocko Subject: Re: [PATCH] mm/memcontrol: update documentation about invoking oom killer In-Reply-To: <157270779336.1961.6528158720593572480.stgit@buzz> Message-ID: References: <157270779336.1961.6528158720593572480.stgit@buzz> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2 Nov 2019, Konstantin Khlebnikov wrote: > Since commit 29ef680ae7c2 ("memcg, oom: move out_of_memory back to the > charge path") memcg invokes oom killer not only for user page-faults. > This means 0-order allocation will either succeed or task get killed. > > Fixes: 8e675f7af507 ("mm/oom_kill: count global and memory cgroup oom kills") > Signed-off-by: Konstantin Khlebnikov > --- > Documentation/admin-guide/cgroup-v2.rst | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > index 5361ebec3361..eb47815e137b 100644 > --- a/Documentation/admin-guide/cgroup-v2.rst > +++ b/Documentation/admin-guide/cgroup-v2.rst > @@ -1219,8 +1219,13 @@ PAGE_SIZE multiple when read back. > > Failed allocation in its turn could be returned into > userspace as -ENOMEM or silently ignored in cases like > - disk readahead. For now OOM in memory cgroup kills > - tasks iff shortage has happened inside page fault. > + disk readahead. > + > + Before 4.19 OOM in memory cgroup killed tasks iff > + shortage has happened inside page fault, random > + syscall may fail with ENOMEM or EFAULT. Since 4.19 > + failed memory cgroup allocation invokes oom killer and > + keeps retrying until it succeeds. > > This event is not raised if the OOM killer is not > considered as an option, e.g. for failed high-order The previous text is obviously incorrect for today's kernels, but I'm curious if we should be conflating the documentation here by describing the pre-4.19 behavior. OOM killing no longer happens only on page fault so maybe better to document the exact behavior today and not attempt to describe differences with previous versions?