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, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID 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 4EECBC28CF6 for ; Thu, 26 Jul 2018 06:10:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F195F20673 for ; Thu, 26 Jul 2018 06:10:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=contabo.de header.i=@contabo.de header.b="Cvct8HIx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F195F20673 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=contabo.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728529AbeGZH0A (ORCPT ); Thu, 26 Jul 2018 03:26:00 -0400 Received: from mail.contabo.com ([91.205.175.50]:54086 "EHLO mail.contabo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726560AbeGZHZ7 (ORCPT ); Thu, 26 Jul 2018 03:25:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=contabo.de; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version :Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=/R2bu6WftCZKNlZTvzndUj/wKEnPOO/y4vWbMyeirLg=; b=Cvct8HIxqGpfk16Q8bruCpfkOS BLAbRBhwMe1T+hF74myVZqWlShTrte4gBMMcnJ+eFs82/NqtPsUaNwTNyXu8vVLddAfO2mR8/bhed ZIOs0ZFikqUolh6QFz4KiaMrsPeakbdSN4aIt+JJsI1eH4hz1fWGbFSxmpfdflVeMDZq3ooqZn4/d A25sfHoBwqn/y5Lmaz6Ka0Vcvni3aR3tAFTPIwIUJzHURVxxYp1e8vWn4ELGaFVhrgfSuN0uwl48B ExrSR6rQ6+pcuvxT6OAO9AC1EhIv1o/8C8vR8kurernRbau3/ePB/v3FT+ljSZOZ1fC/o8a8oms8n ldZrT1Rg==; Received: from [178.238.239.246] (port=30200 helo=[192.168.178.123]) by mail.contabo.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.91) (envelope-from ) id 1fiZU1-00013k-OS; Thu, 26 Jul 2018 08:10:41 +0200 Subject: Re: Zram writeback feature unstable with heavy swap utilization - BUG: Bad page state in process... To: Minchan Kim Cc: ngupta@vflare.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky , Andrew Morton References: <0516ae2d-b0fd-92c5-aa92-112ba7bd32fc@contabo.de> <20180724010342.GA195675@rodete-desktop-imager.corp.google.com> <20180725132126.GA2893@rodete-laptop-imager.corp.google.com> <20180726020351.GA221405@rodete-desktop-imager.corp.google.com> From: Tino Lehnig Message-ID: <1684cefc-c920-d53c-8d2d-c32da213a045@contabo.de> Date: Thu, 26 Jul 2018 08:10:41 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180726020351.GA221405@rodete-desktop-imager.corp.google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - mail.contabo.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - contabo.de X-Get-Message-Sender-Via: mail.contabo.com: authenticated_id: tino.lehnig@contabo.de X-Authenticated-Sender: mail.contabo.com: tino.lehnig@contabo.de Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 07/26/2018 04:03 AM, Minchan Kim wrote: > A thing I could imagine is > [0bcac06f27d75, skip swapcache for swapin of synchronous device] > It was merged into v4.15. Could you check it by bisecting? Thanks, I will check that. >> My operating system is a minimal install of Debian 9. I took the kernel >> configuration from the default Debian kernel and built my own kernel with >> "make oldconfig" leaving all settings at their defaults. The only thing I >> changed in the configuration was enabling the zram writeback feature. > > You mean you changed host kernel configuration? > >> >> All my tests were done on bare-metal hardware with Xeon processors and lots >> of RAM. I encounter the bug quite quickly, but it still takes several GBs of >> swap usage. Below is my /proc/meminfo with enough KVM instances running (3 >> in my case) to trigger the bug on my test machine. > > Aha.. you did writeback feature into your bare-metal host machine and execute > kvm with window images as a guest. So, PG_uptodate warning happens on host side, > not guest? Right? Yes, I am only talking about the host kernel. Zram swap is set up on the host. I just used Windows guests to fill up the host RAM and force it into swap. >> I will also try to reproduce the problem on some different hardware next. Just to confirm, I was able to reproduce the problem on another machine running Ubuntu 18.04 with the Ubuntu stock kernel (4.15) and no modifications to the kernel configuration whatsoever. The host had 8 GB of RAM, 32 GB of swap with zram and a 32 GB SSD as backing device. I had to start only one Windows VM with "-m 32768" to trigger the bug. -- Kind regards, Tino Lehnig