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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 EB26BC5ACD7 for ; Wed, 18 Mar 2020 09:57:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1A4220767 for ; Wed, 18 Mar 2020 09:57:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584525435; bh=PxOugapyiLyGM41ij3qU4It93Jbk5/RLhf0dug/PLy8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=qvqjpQ7chAtvevrEHyMSMqgu5bF4aaeNayBrqVwmAUeinsva947SdYGtwpOp45HBq jDpU2GP7ei7InKMT05jgV0zSqXxY/CLthyIvMHZhVEHY04TyhNg6lvqYBELlThxYpQ FFYIAB2h3FXIabvlSXDSnABQDRtRzxEvLtU2C4xo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727569AbgCRJ5O (ORCPT ); Wed, 18 Mar 2020 05:57:14 -0400 Received: from mail-wr1-f48.google.com ([209.85.221.48]:37715 "EHLO mail-wr1-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727405AbgCRJ5O (ORCPT ); Wed, 18 Mar 2020 05:57:14 -0400 Received: by mail-wr1-f48.google.com with SMTP id w10so631428wrm.4 for ; Wed, 18 Mar 2020 02:57:13 -0700 (PDT) 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:message-id:references :mime-version:content-disposition:in-reply-to; bh=GOcmbfCGsBYkxr9ElKbbF2lKiCO06vnAuf1KQJx6gnM=; b=X+judH+b0yjx8AzNhOcwU3Zp/ihld72xOPu9nScQ8noVWGjjMWGAqd6Wvpx7drlYic TZFZwzle7z0FZRrYAjf2aeSkltepaiC1BMl1fmvRBDF83q9ARiyvAceqcRKEUxuMXNdX G41Fj6TPgwnMtvXxIqTG8VH4HMBfHN1lHhK0rXL/qFZh4XV6wlFo8pcUZdQbPJEPN5n7 QwGWBL8V78L+/pwoCvv75k/DgQw8HF5TkQ3EdTGdq7xOwGCgVvpgmTfXwn2LqekDCOus gdAKwyRMRA+xbf7AjxWpFP0bKvWcH5YOn01UG+kVR+xYJExJh2KRWWb3H4oeQYhuErUH /Eig== X-Gm-Message-State: ANhLgQ2pnZxCkSsPmyoe/0GvJ85cFDvnGkjKrinlvaFmMFPxP2whB3+q CA8vkkn9fcDDYOmVjDh3ZcE= X-Google-Smtp-Source: ADFU+vvBHA61twBo/iJCkAyPfb8alCOE0RxXYb3BGFv8E2BcCaIptytGe1N2yy2yIUN1EMDdUQzxpQ== X-Received: by 2002:adf:ea42:: with SMTP id j2mr4642015wrn.3.1584525432444; Wed, 18 Mar 2020 02:57:12 -0700 (PDT) Received: from localhost (ip-37-188-180-89.eurotel.cz. [37.188.180.89]) by smtp.gmail.com with ESMTPSA id s7sm8708665wro.10.2020.03.18.02.57.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Mar 2020 02:57:11 -0700 (PDT) Date: Wed, 18 Mar 2020 10:57:10 +0100 From: Michal Hocko To: Ami Fischman Cc: Robert Kolchmeyer , David Rientjes , Andrew Morton , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch] mm, oom: make a last minute check to prevent unnecessary memcg oom kills Message-ID: <20200318095710.GG21362@dhcp22.suse.cz> References: <20200310221938.GF8447@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 17-03-20 12:00:45, Ami Fischman wrote: > On Tue, Mar 17, 2020 at 11:26 AM Robert Kolchmeyer > wrote: > > > > On Tue, Mar 10, 2020 at 3:54 PM David Rientjes wrote: > > > > > > Robert, could you elaborate on the user-visible effects of this issue that > > > caused it to initially get reported? > > > > Ami (now cc'ed) knows more, but here is my understanding. > > Robert's description of the mechanics we observed is accurate. > > We discovered this regression in the oom-killer's behavior when > attempting to upgrade our system. The fraction of the system that > went unhealthy due to this issue was approximately equal to the > _sum_ of all other causes of unhealth, which are many and varied, > but each of which contribute only a small amount of > unhealth. This issue forced a rollback to the previous kernel > where we ~never see this behavior, returning our unhealth levels > to the previous background levels. Could you be more specific on the good vs. bad kernel versions? Because I do not remember any oom changes that would affect the time-to-check-time-to-kill race. The timing might be slightly different in each kernel version of course. -- Michal Hocko SUSE Labs