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 62FBFECE58E for ; Tue, 8 Oct 2019 14:09:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3FFD321721 for ; Tue, 8 Oct 2019 14:09:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FFD321721 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 CF86D8E0005; Tue, 8 Oct 2019 10:09:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CA8E28E0003; Tue, 8 Oct 2019 10:09:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B97D18E0005; Tue, 8 Oct 2019 10:09:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0190.hostedemail.com [216.40.44.190]) by kanga.kvack.org (Postfix) with ESMTP id 9A86D8E0003 for ; Tue, 8 Oct 2019 10:09:01 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 45D52181AC9B4 for ; Tue, 8 Oct 2019 14:09:01 +0000 (UTC) X-FDA: 76020798882.20.dress66_6bd0126192e5a X-HE-Tag: dress66_6bd0126192e5a X-Filterd-Recvd-Size: 2202 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Tue, 8 Oct 2019 14:09:00 +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 668A1AC45; Tue, 8 Oct 2019 14:08:59 +0000 (UTC) Date: Tue, 8 Oct 2019 16:08:58 +0200 From: Michal Hocko To: Qian Cai Cc: Petr Mladek , Steven Rostedt , sergey.senozhatsky.work@gmail.com, peterz@infradead.org, linux-mm@kvack.org, john.ogness@linutronix.de, akpm@linux-foundation.org, david@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk() Message-ID: <20191008140858.GN6681@dhcp22.suse.cz> References: <1570228005-24979-1-git-send-email-cai@lca.pw> <20191007143002.l37bt2lzqtnqjqxu@pathway.suse.cz> <1570460350.5576.290.camel@lca.pw> <20191007151237.GP2381@dhcp22.suse.cz> <1570462407.5576.292.camel@lca.pw> <20191008081510.ptwmb7zflqiup5py@pathway.suse.cz> <20191008091349.6195830d@gandalf.local.home> <1570541032.5576.297.camel@lca.pw> <20191008134256.5ti6rjkvadn5b5q4@pathway.suse.cz> <1570543381.5576.301.camel@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1570543381.5576.301.camel@lca.pw> User-Agent: Mutt/1.10.1 (2018-07-13) 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 08-10-19 10:03:01, Qian Cai wrote: [..] > I don't think there is "removing useful messages" in this patch. That one > printk() in __offline_isolated_pages() basically as Michal mentioned it is that > useful, but could be converted to printk_deferred() if anyone objected. "remove from free list" printk is quite dubious as I've said. And I wouldn't be opposed to remove it altogether. It just swamps the low with something that is of no real use. It might have been useful while shaping and debugging the initial code but it has close to zero value for end users. But it makes no sense to make to make it printk_deferred on grounds mentioned so far. -- Michal Hocko SUSE Labs