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=-2.5 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 18419C4360C for ; Thu, 10 Oct 2019 10:59:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D4C87206B6 for ; Thu, 10 Oct 2019 10:59:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4C87206B6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 58B6F6B0003; Thu, 10 Oct 2019 06:59:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 53B378E0003; Thu, 10 Oct 2019 06:59:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 451066B0006; Thu, 10 Oct 2019 06:59:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0023.hostedemail.com [216.40.44.23]) by kanga.kvack.org (Postfix) with ESMTP id 1DA936B0003 for ; Thu, 10 Oct 2019 06:59:31 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id ADA928153 for ; Thu, 10 Oct 2019 10:59:30 +0000 (UTC) X-FDA: 76027578900.23.milk29_18cad02a58a56 X-HE-Tag: milk29_18cad02a58a56 X-Filterd-Recvd-Size: 2197 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Thu, 10 Oct 2019 10:59:30 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 7F349B17F; Thu, 10 Oct 2019 10:59:28 +0000 (UTC) Date: Thu, 10 Oct 2019 12:59:27 +0200 From: Michal Hocko To: Qian Cai Cc: Petr Mladek , Christian Borntraeger , Heiko Carstens , sergey.senozhatsky.work@gmail.com, rostedt@goodmis.org, peterz@infradead.org, linux-mm@kvack.org, john.ogness@linutronix.de, akpm@linux-foundation.org, Vasily Gorbik , Peter Oberparleiter , david@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk() Message-ID: <20191010105927.GG18412@dhcp22.suse.cz> References: <20191009162339.GI6681@dhcp22.suse.cz> <6AAB77B5-092B-43E3-9F4B-0385DE1890D9@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6AAB77B5-092B-43E3-9F4B-0385DE1890D9@lca.pw> User-Agent: Mutt/1.10.1 (2018-07-13) Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000056, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu 10-10-19 05:01:44, Qian Cai wrote: >=20 >=20 > > On Oct 9, 2019, at 12:23 PM, Michal Hocko wrote: > >=20 > > If this was only about the memory offline code then I would agree. Bu= t > > we are talking about any printk from the zone->lock context and that = is > > a bigger deal. Besides that it is quite natural that the printk code > > should be more universal and allow to be also called from the MM > > contexts as much as possible. If there is any really strong reason th= is > > is not possible then it should be documented at least. >=20 > Where is the best place to document this? I am thinking about under > the =E2=80=9Cstruct zone=E2=80=9D definition=E2=80=99s lock field in mm= zone.h. I am not sure TBH and I do not think we have reached the state where this would be the only way forward. --=20 Michal Hocko SUSE Labs