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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,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 598D7C43463 for ; Fri, 18 Sep 2020 05:49:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D902220866 for ; Fri, 18 Sep 2020 05:49:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D902220866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 14C256B0055; Fri, 18 Sep 2020 01:49:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0FDB96B005A; Fri, 18 Sep 2020 01:49:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0126C6B005C; Fri, 18 Sep 2020 01:49:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0081.hostedemail.com [216.40.44.81]) by kanga.kvack.org (Postfix) with ESMTP id E05D46B0055 for ; Fri, 18 Sep 2020 01:49:15 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id A2062362B for ; Fri, 18 Sep 2020 05:49:15 +0000 (UTC) X-FDA: 77275104270.21.fruit38_53179c027128 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id 82E1A180442C4 for ; Fri, 18 Sep 2020 05:49:15 +0000 (UTC) X-HE-Tag: fruit38_53179c027128 X-Filterd-Recvd-Size: 2865 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Fri, 18 Sep 2020 05:49:14 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id DBB02ACC8; Fri, 18 Sep 2020 05:49:46 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 18 Sep 2020 07:49:11 +0200 From: osalvador@suse.de To: =?UTF-8?Q?HORIGUCHI_NAOYA=28=E5=A0=80=E5=8F=A3=E3=80=80=E7=9B=B4?= =?UTF-8?Q?=E4=B9=9F=29?= Cc: akpm@linux-foundation.org, aris@ruivo.org, mhocko@kernel.org, tony.luck@intel.com, cai@lca.pw, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v4 0/7] HWpoison: further fixes and cleanups In-Reply-To: <20200917152717.GA26808@hori.linux.bs1.fc.nec.co.jp> References: <20200917081049.27428-1-osalvador@suse.de> <20200917113920.GA19898@hori.linux.bs1.fc.nec.co.jp> <20200917130948.GA1812@linux> <20200917133959.GA2504@linux> <20200917152717.GA26808@hori.linux.bs1.fc.nec.co.jp> User-Agent: Roundcube Webmail Message-ID: X-Sender: osalvador@suse.de X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2020-09-17 17:27, HORIGUCHI NAOYA wrote: > Sorry, I modified the patches based on the different assumption from > yours. > I firstly thought of taking page off after confirming the error page > is freed back to buddy. This approach leaves the possibility of reusing > the error page (which is acceptable), but simpler and less invasive > one. > > Your approach removes the error page from page allocator's control in > freeing time. It has no possibility of reusing the error page but > changes > are tightly coupled with page free code. > > This is a tradeoff between complexity and completeness of soft offline, > Now I'm not sure I could persist on my own opinion without providing > working code, and it's OK for me to take your one. Yeah, you are right it is a trade off. I would suggest taking this path now, and if it proofs to be problematic in some way, we can always do the: free_page take_it_off_buddy OK: mark it as hwpoison and increment refcount NOT_OK (raced with allocation): oops, sorry > The test passed in my environment, so this is fine. Thanks for trying it out. > >> If they do, I will try to see if Andrew can squezee above changes into >> [1], >> where they belong to. > > Yes, proposing the fix for > mmhwpoison-rework-soft-offline-for-in-use-pages.patch > seems fine to me. > > Again, sorry for modifying code without asking. No worries, I wil do a couple of tests on my own and then I will talk to Andrew to see if we can squeeze the changes in there.