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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 231DBC4724C for ; Fri, 1 May 2020 01:40:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BF582208CA for ; Fri, 1 May 2020 01:39:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aeTR70bQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF582208CA 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 5056B8E0005; Thu, 30 Apr 2020 21:39:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4B5618E0001; Thu, 30 Apr 2020 21:39:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3CA478E0005; Thu, 30 Apr 2020 21:39:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0096.hostedemail.com [216.40.44.96]) by kanga.kvack.org (Postfix) with ESMTP id 231A78E0001 for ; Thu, 30 Apr 2020 21:39:59 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id E077E3D13 for ; Fri, 1 May 2020 01:39:58 +0000 (UTC) X-FDA: 76766444076.08.women45_1ce7dfffd114b X-HE-Tag: women45_1ce7dfffd114b X-Filterd-Recvd-Size: 7579 Received: from mail-io1-f65.google.com (mail-io1-f65.google.com [209.85.166.65]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Fri, 1 May 2020 01:39:58 +0000 (UTC) Received: by mail-io1-f65.google.com with SMTP id z2so3620966iol.11 for ; Thu, 30 Apr 2020 18:39:58 -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=9kEjlo9klnfQZPRmxb764xpSlEiJoEeAxtPwpEWsyW8=; b=aeTR70bQPdhn7Tq42eH9wJCqPBsI8z+1fnVg9Sp1WiL/y90sV5ktBNmBHZI4N8MO4B xrgA5Gnrqf57Shq4bgUrhgVjbUUcLmd3kckR0w89uFJtMZ2OKBZr9zM1EXSqaQK6mhOy A5Fe63ZfurRQ8pVW1kE9UwEZEvF+c4iLHutlCqcshY+L2RPb3sR9Ei0HGePE1c/SkbZV WO/oF8lUVItDI18HzZvm/RWyLyufmnxXW941m0b9CDslbASKKECozA4yZJZFQbMCgE7S 5aEkNxO+2XseuXmRdXYIgasPV26hZcZNY6Gn6jf0Eiu5hbGNf9ar+yhp67lgVqm7kzmq tR1A== 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=9kEjlo9klnfQZPRmxb764xpSlEiJoEeAxtPwpEWsyW8=; b=MQaOZ8MoFoXTSkbEaQ5xk316CFA71H7NMH6/QUCJHPsMIEyNiOAAOnXaYl/rNxRo3a sqOawmHzJjxCw2orvSBL47y+KNCcEN8pdkcEXGCDdhz/u0bj+RRzWc7CPj/O2NPHGawF SK7CdnKOJaEJb0Ah1NoF7cCSBFolKCjqX2aldmAy6YnAriD4yhNecbYFzeP2oxCXDwnx tpLaqcFEiLogm0Bx38LUI1z0gnIICSoPkpXk5/sG9mNKYGcOMtbwF84paIWZ6NMZfCLN UMHWrovjZ555n3JqTl14GSDvo+M4e0oJTPRAxZLYkcsVamYRWALc+PO+L+IlUWwK82iv b7rQ== X-Gm-Message-State: AGi0PuZAKCZmSwG0bMheylDAwr3ADe99vZSngh2xqFRPi+QyGcyhCgah noknjExTbbkMVdwCakJP1lI5KooXVgxxtVmWg98= X-Google-Smtp-Source: APiQypLamne0OBmpP4DO5r8KXtbkzJtEpn4HPlEEm5ULy1L+FjtwRO4uwqFP29YjTbX2rUq4btja/JKPuyFbykgrUMw= X-Received: by 2002:a6b:3c0a:: with SMTP id k10mr1789356iob.10.1588297197906; Thu, 30 Apr 2020 18:39:57 -0700 (PDT) MIME-Version: 1.0 References: <20200430182712.237526-1-shakeelb@google.com> In-Reply-To: <20200430182712.237526-1-shakeelb@google.com> From: Yafang Shao Date: Fri, 1 May 2020 09:39:24 +0800 Message-ID: Subject: Re: [PATCH] memcg: oom: ignore oom warnings from memory.max To: Shakeel Butt Cc: Johannes Weiner , Roman Gushchin , Michal Hocko , Greg Thelen , Andrew Morton , Linux MM , Cgroups , LKML 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 Fri, May 1, 2020 at 2:27 AM Shakeel Butt wrote: > > Lowering memory.max can trigger an oom-kill if the reclaim does not > succeed. However if oom-killer does not find a process for killing, it > dumps a lot of warnings. > I have been confused by this behavior for several months and I think it will confuse more memcg users. We should keep the memcg oom behavior consistent with system oom - no oom kill if no process. What about bellow change ? diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e28098e13f1c..25fbc37a747f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6086,6 +6086,9 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, continue; } + if (!cgroup_is_populated(memcg->css.cgroup)) + break; + memcg_memory_event(memcg, MEMCG_OOM); if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0)) break; > Deleting a memcg does not reclaim memory from it and the memory can > linger till there is a memory pressure. One normal way to proactively > reclaim such memory is to set memory.max to 0 just before deleting the > memcg. However if some of the memcg's memory is pinned by others, this > operation can trigger an oom-kill without any process and thus can log a > lot un-needed warnings. So, ignore all such warnings from memory.max. > > Signed-off-by: Shakeel Butt > --- > include/linux/oom.h | 3 +++ > mm/memcontrol.c | 9 +++++---- > mm/oom_kill.c | 2 +- > 3 files changed, 9 insertions(+), 5 deletions(-) > > diff --git a/include/linux/oom.h b/include/linux/oom.h > index c696c265f019..6345dc55df64 100644 > --- a/include/linux/oom.h > +++ b/include/linux/oom.h > @@ -52,6 +52,9 @@ struct oom_control { > > /* Used to print the constraint info. */ > enum oom_constraint constraint; > + > + /* Do not warn even if there is no process to be killed. */ > + bool no_warn; > }; > > extern struct mutex oom_lock; > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 317dbbaac603..a1f00d9b9bb0 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1571,7 +1571,7 @@ unsigned long mem_cgroup_size(struct mem_cgroup *memcg) > } > > static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, > - int order) > + int order, bool no_warn) > { > struct oom_control oc = { > .zonelist = NULL, > @@ -1579,6 +1579,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, > .memcg = memcg, > .gfp_mask = gfp_mask, > .order = order, > + .no_warn = no_warn, > }; > bool ret; > > @@ -1821,7 +1822,7 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int > mem_cgroup_oom_notify(memcg); > > mem_cgroup_unmark_under_oom(memcg); > - if (mem_cgroup_out_of_memory(memcg, mask, order)) > + if (mem_cgroup_out_of_memory(memcg, mask, order, false)) > ret = OOM_SUCCESS; > else > ret = OOM_FAILED; > @@ -1880,7 +1881,7 @@ bool mem_cgroup_oom_synchronize(bool handle) > mem_cgroup_unmark_under_oom(memcg); > finish_wait(&memcg_oom_waitq, &owait.wait); > mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask, > - current->memcg_oom_order); > + current->memcg_oom_order, false); > } else { > schedule(); > mem_cgroup_unmark_under_oom(memcg); > @@ -6106,7 +6107,7 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, > } > > memcg_memory_event(memcg, MEMCG_OOM); > - if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0)) > + if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0, true)) > break; > } > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 463b3d74a64a..5ace39f6fe1e 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -1098,7 +1098,7 @@ bool out_of_memory(struct oom_control *oc) > > select_bad_process(oc); > /* Found nothing?!?! */ > - if (!oc->chosen) { > + if (!oc->chosen && !oc->no_warn) { > dump_header(oc, NULL); > pr_warn("Out of memory and no killable processes...\n"); > /* > -- > 2.26.2.526.g744177e7f7-goog > > -- Thanks Yafang