From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) by kanga.kvack.org (Postfix) with ESMTP id 2D4296B04CD for ; Tue, 30 Oct 2018 04:16:43 -0400 (EDT) Received: by mail-pl1-f200.google.com with SMTP id bb3-v6so8612625plb.20 for ; Tue, 30 Oct 2018 01:16:43 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id k3-v6si14614936pgm.517.2018.10.30.01.16.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Oct 2018 01:16:42 -0700 (PDT) Date: Tue, 30 Oct 2018 09:16:39 +0100 From: Michal Hocko Subject: Re: [PATCH v2 0/2] mm: soft-offline: fix race against page allocation Message-ID: <20181030081639.GW32673@dhcp22.suse.cz> References: <1531805552-19547-1-git-send-email-n-horiguchi@ah.jp.nec.com> <20180815154334.f3eecd1029a153421631413a@linux-foundation.org> <20180822013748.GA10343@hori1.linux.bs1.fc.nec.co.jp> <20180822080025.GD29735@dhcp22.suse.cz> <20181026084636.GY18839@dhcp22.suse.cz> <20181030065433.GA1119@hori1.linux.bs1.fc.nec.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181030065433.GA1119@hori1.linux.bs1.fc.nec.co.jp> Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi Cc: Andrew Morton , "linux-mm@kvack.org" , "xishi.qiuxishi@alibaba-inc.com" , "zy.zhengyi@alibaba-inc.com" , "linux-kernel@vger.kernel.org" , Mike Kravetz On Tue 30-10-18 06:54:33, Naoya Horiguchi wrote: > On Fri, Oct 26, 2018 at 10:46:36AM +0200, Michal Hocko wrote: > > On Wed 22-08-18 10:00:25, Michal Hocko wrote: > > > On Wed 22-08-18 01:37:48, Naoya Horiguchi wrote: > > > > On Wed, Aug 15, 2018 at 03:43:34PM -0700, Andrew Morton wrote: > > > > > On Tue, 17 Jul 2018 14:32:30 +0900 Naoya Horiguchi wrote: > > > > > > > > > > > I've updated the patchset based on feedbacks: > > > > > > > > > > > > - updated comments (from Andrew), > > > > > > - moved calling set_hwpoison_free_buddy_page() from mm/migrate.c to mm/memory-failure.c, > > > > > > which is necessary to check the return code of set_hwpoison_free_buddy_page(), > > > > > > - lkp bot reported a build error when only 1/2 is applied. > > > > > > > > > > > > > mm/memory-failure.c: In function 'soft_offline_huge_page': > > > > > > > >> mm/memory-failure.c:1610:8: error: implicit declaration of function > > > > > > > 'set_hwpoison_free_buddy_page'; did you mean 'is_free_buddy_page'? > > > > > > > [-Werror=implicit-function-declaration] > > > > > > > if (set_hwpoison_free_buddy_page(page)) > > > > > > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > > > > is_free_buddy_page > > > > > > > cc1: some warnings being treated as errors > > > > > > > > > > > > set_hwpoison_free_buddy_page() is defined in 2/2, so we can't use it > > > > > > in 1/2. Simply doing s/set_hwpoison_free_buddy_page/!TestSetPageHWPoison/ > > > > > > will fix this. > > > > > > > > > > > > v1: https://lkml.org/lkml/2018/7/12/968 > > > > > > > > > > > > > > > > Quite a bit of discussion on these two, but no actual acks or > > > > > review-by's? > > > > > > > > Really sorry for late response. > > > > Xishi provided feedback on previous version, but no final ack/reviewed-by. > > > > This fix should work on the reported issue, but rewriting soft-offlining > > > > without PageHWPoison flag would be the better fix (no actual patch yet.) > > > > > > If we can go with the later the I would obviously prefer that. I cannot > > > promise to work on the patch though. I can help with reviewing of > > > course. > > > > > > If this is important enough that people are hitting the issue in normal > > > workloads then sure, let's go with the simple fix and continue on top of > > > that. > > > > Naoya, did you have any chance to look at this or have any plans to look? > > I am willing to review and help with the overal design but I cannot > > really promise to work on the code. > > I have a draft version of a patch to isolate a page in buddy-friendly manner > without PageHWPoison flag (that was written weeks ago, but I couldn't finish > because my other project interrupted me ...). > I'll post it after testing, especially confirming that hotplug code properly > reset the isolated page. Thanks a lot Naoya. It is highly appreciated! -- Michal Hocko SUSE Labs