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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 2FEE5C2D0CE for ; Wed, 22 Jan 2020 00:42:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EFFFC2253D for ; Wed, 22 Jan 2020 00:42:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EFFFC2253D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A57AC6B0006; Tue, 21 Jan 2020 19:42:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A08D06B000E; Tue, 21 Jan 2020 19:42:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 946276B0010; Tue, 21 Jan 2020 19:42:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0107.hostedemail.com [216.40.44.107]) by kanga.kvack.org (Postfix) with ESMTP id 7C2106B0006 for ; Tue, 21 Jan 2020 19:42:15 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 29B952DFA for ; Wed, 22 Jan 2020 00:42:15 +0000 (UTC) X-FDA: 76403418630.13.hour96_6ae4007d18f54 X-HE-Tag: hour96_6ae4007d18f54 X-Filterd-Recvd-Size: 3950 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Wed, 22 Jan 2020 00:42:14 +0000 (UTC) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Jan 2020 16:42:12 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,347,1574150400"; d="scan'208";a="425679164" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga005.fm.intel.com with ESMTP; 21 Jan 2020 16:42:11 -0800 Date: Wed, 22 Jan 2020 08:42:22 +0800 From: Wei Yang To: John Hubbard Cc: Wei Yang , akpm@linux-foundation.org, yang.shi@linux.alibaba.com, vbabka@suse.cz, cl@linux.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@kernel.org Subject: Re: [Patch v2] mm/migrate.c: also overwrite error when it is bigger than zero Message-ID: <20200122004222.GD11409@richard> Reply-To: Wei Yang References: <20200119065753.21694-1-richardw.yang@linux.intel.com> <20200121015326.GE1567@richard> <20200121023408.GA3636@richard> <0aa42c19-4144-5c7a-10f5-162b1b068d4c@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0aa42c19-4144-5c7a-10f5-162b1b068d4c@nvidia.com> User-Agent: Mutt/1.9.4 (2018-02-28) 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 Tue, Jan 21, 2020 at 11:33:16AM -0800, John Hubbard wrote: >On 1/20/20 6:34 PM, Wei Yang wrote: >> On Tue, Jan 21, 2020 at 09:53:26AM +0800, Wei Yang wrote: >> > On Sun, Jan 19, 2020 at 02:57:53PM +0800, Wei Yang wrote: >> > > If we get here after successfully adding page to list, err would be >> > > 1 to indicate the page is queued in the list. >> > > >> > > Current code has two problems: >> > > >> > > * on success, 0 is not returned >> > > * on error, if add_page_for_migratioin() return 1, and the following err1 >> > > from do_move_pages_to_node() is set, the err1 is not returned since err >> > > is 1 >> > > >> > > And these behaviors break the user interface. >> > > >> > > Fixes: e0153fc2c760 ("mm: move_pages: return valid node id in status if the >> > > page is already on the target node"). > >The Fixes tag should be different, right? Because I don't think that >commit introduced this problem. This is the correct one. Before this, we don't return 1 from add_page_for_migration(). > >thanks, >-- >John Hubbard >NVIDIA > >> > > Signed-off-by: Wei Yang >> > > >> > > --- >> > > v2: >> > > * put more words to explain the error case >> > > --- >> > > mm/migrate.c | 2 +- >> > > 1 file changed, 1 insertion(+), 1 deletion(-) >> > > >> > > diff --git a/mm/migrate.c b/mm/migrate.c >> > > index 86873b6f38a7..430fdccc733e 100644 >> > > --- a/mm/migrate.c >> > > +++ b/mm/migrate.c >> > > @@ -1676,7 +1676,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, >> > > err1 = do_move_pages_to_node(mm, &pagelist, current_node); >> > > if (!err1) >> > > err1 = store_status(status, start, current_node, i - start); >> > > - if (!err) >> > > + if (err >= 0) >> > > err = err1; >> > >> > Ok, as mentioned by Yang and Michal, only err == 0 means no error. >> > >> > Sounds this regression should be fixed in another place. Let me send out >> > another patch. >> > >> >> Hmm... I took another look into the case, this fix should work. >> >> But yes, the semantic here is a little confusion. Look forward your comments >> here. >> >> > > out: >> > > return err; >> > > -- >> > > 2.17.1 >> > >> > -- >> > Wei Yang >> > Help you, Help me >> > >thanks, >-- >John Hubbard >NVIDIA -- Wei Yang Help you, Help me