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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F613C433EF for ; Fri, 27 May 2022 06:36:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 866A78D0005; Fri, 27 May 2022 02:36:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 815DA8D0001; Fri, 27 May 2022 02:36:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7027B8D0005; Fri, 27 May 2022 02:36:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 602708D0001 for ; Fri, 27 May 2022 02:36:56 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2914E210B6 for ; Fri, 27 May 2022 06:36:56 +0000 (UTC) X-FDA: 79510565232.07.7B2E84F Received: from mail-pl1-f174.google.com (mail-pl1-f174.google.com [209.85.214.174]) by imf02.hostedemail.com (Postfix) with ESMTP id 7E43080010 for ; Fri, 27 May 2022 06:36:51 +0000 (UTC) Received: by mail-pl1-f174.google.com with SMTP id f18so3394393plg.0 for ; Thu, 26 May 2022 23:36:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=SuokLXZBT769hHza25K/JKzYPz4okNLCTIvug/IPsOQ=; b=w/Dtt17bexhMQfEO6bZdS8g76rcXfd1fCxzoZiPupXvbG6D1PCjYICkTcZoXMchs33 XwQDdljexH8C7HWpuWkcd0aabZDZmfOs37/pSWL2o/Ma2ckuRkSN4tVLxE3BGT8SjmmZ /JHpZM9duuHTTZ/hqxVnt4BMWzchBWwfjfx1TZXxxn3s7cEvgS8S/aWR+aakyvAW8LGi BUHH0av/nN3KGi26NcaMjBdfZ6bmAo2QAxjbYMkVFw675/L/X8gkdLIELP7ZP9Myzhz7 vQ/X1Rz9UX2xuO+xfYfn6QqA/MsysGxlfvyPQco5aSoo19c6jl7B2GTMxIfcgqs9i2YR xeyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=SuokLXZBT769hHza25K/JKzYPz4okNLCTIvug/IPsOQ=; b=gnBWpq2Kpiw0WDFP5pEsWkK8KBIu9MXdvPdmDmB4EP2otT48Gfjd/4rBArgkaqR+tZ 1//vgX8fSH93CUY0sjVw9sbGcVzhZacVm4C40AAtTcGBNyUHTUhSVv7uGGa49abdD+xg zC52t5bfpT/E+PAhmBxGIsM7RYN/yucgRxnCmEv6X6ak3eGyXt7JJrK/15dgjBg50zOO 9b/QlGsKT0mUetlGGWOZdf62pxizv/4rAMFzWp6GdoVKePJJVVznSSoL6AIXw7ExOGQK BtXRrpIZNRrpbJ9l6ArhxByzWDkm090vFPXW4tFG1Fc1+HaVqpa9dpflITXOYw0u6f72 3FNQ== X-Gm-Message-State: AOAM533VCNadz7RadtpOT3Ctkgyb0YlQrRYV+tzkgtFoQJjOJjK4FESi z/1P0rUcaCvYDb5EIyRXZRP2Bg== X-Google-Smtp-Source: ABdhPJxOPiXIhe6VKd4CALjITeyKD3bUphXadgcUtVKUa901LvCRw8JDURlFy6QfYahvehfnBi6M3g== X-Received: by 2002:a17:90a:bb17:b0:1e0:ab18:4491 with SMTP id u23-20020a17090abb1700b001e0ab184491mr6583871pjr.120.1653633413656; Thu, 26 May 2022 23:36:53 -0700 (PDT) Received: from [10.255.70.20] ([139.177.225.235]) by smtp.gmail.com with ESMTPSA id m9-20020a63ed49000000b003f9d1c020cbsm2619464pgk.51.2022.05.26.23.36.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 26 May 2022 23:36:52 -0700 (PDT) Message-ID: <24a95dea-9ea6-a904-7c0b-197961afa1d1@bytedance.com> Date: Fri, 27 May 2022 14:32:52 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: Re: [PATCH 0/3] recover hardware corrupted page by virtio balloon Content-Language: en-US To: Peter Xu , Jue Wang Cc: Andrew Morton , David Hildenbrand , jasowang@redhat.com, LKML , Linux MM , mst@redhat.com, =?UTF-8?B?SE9SSUdVQ0hJIE5BT1lBKOWggOWPoyDnm7TkuZ8p?= , Paolo Bonzini , qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org References: From: zhenwei pi In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 7E43080010 X-Stat-Signature: j9jch1s35gubrmfai574emtndx9yq7i7 Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b="w/Dtt17b"; dmarc=pass (policy=none) header.from=bytedance.com; spf=pass (imf02.hostedemail.com: domain of pizhenwei@bytedance.com designates 209.85.214.174 as permitted sender) smtp.mailfrom=pizhenwei@bytedance.com X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1653633411-919153 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 5/27/22 02:37, Peter Xu wrote: > On Wed, May 25, 2022 at 01:16:34PM -0700, Jue Wang wrote: >> The hypervisor _must_ emulate poisons identified in guest physical >> address space (could be transported from the source VM), this is to >> prevent silent data corruption in the guest. With a paravirtual >> approach like this patch series, the hypervisor can clear some of the >> poisoned HVAs knowing for certain that the guest OS has isolated the >> poisoned page. I wonder how much value it provides to the guest if the >> guest and workload are _not_ in a pressing need for the extra KB/MB >> worth of memory. > > I'm curious the same on how unpoisoning could help here. The reasoning > behind would be great material to be mentioned in the next cover letter. > > Shouldn't we consider migrating serious workloads off the host already > where there's a sign of more severe hardware issues, instead? > > Thanks, > I'm maintaining 1000,000+ virtual machines, from my experience: UE is quite unusual and occurs randomly, and I did not hit UE storm case in the past years. The memory also has no obvious performance drop after hitting UE. I hit several CE storm case, the performance memory drops a lot. But I can't find obvious relationship between UE and CE. So from the point of my view, to fix the corrupted page for VM seems good enough. And yes, unpoisoning several pages does not help significantly, but it is still a chance to make the virtualization better. -- zhenwei pi