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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 3890DCA90AF for ; Wed, 13 May 2020 12:19:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E4252078C for ; Wed, 13 May 2020 12:19:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732537AbgEMMTq (ORCPT ); Wed, 13 May 2020 08:19:46 -0400 Received: from mx2.suse.de ([195.135.220.15]:42272 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726020AbgEMMTq (ORCPT ); Wed, 13 May 2020 08:19:46 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 5D36DAF4C; Wed, 13 May 2020 12:19:47 +0000 (UTC) Date: Wed, 13 May 2020 14:19:42 +0200 From: Petr Mladek To: Tetsuo Handa Cc: Michal Hocko , Sergey Senozhatsky , Steven Rostedt , linux-kernel@vger.kernel.org, Dmitry Safonov , Yafang Shao Subject: Re: [PATCH] printk: Add loglevel for "do not print to consoles". Message-ID: <20200513121942.GK17734@linux-b0ei> References: <20200428154532.GU28637@dhcp22.suse.cz> <20200429142106.GG28637@dhcp22.suse.cz> <20200513062652.GM413@jagdpanzerIV.localdomain> <20200513100413.GH17734@linux-b0ei> <20200513104938.GW29153@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2020-05-13 20:24:24, Tetsuo Handa wrote: > On 2020/05/13 19:49, Michal Hocko wrote: > > On Wed 13-05-20 12:04:13, Petr Mladek wrote: > >> What is so special about OOM dump task so that it would deserve such > >> complications? > I don't think dump_tasks() is important information to be printed on consoles. > But since somebody might think dump_tasks() is important information to be > printed on consoles, I suggest switching KERN_NO_CONSOLES using e.g. sysctl. You might achieve the same with DEBUG loglevel. Or do I miss anything? > There is per-console loglevel proposal (which allows selecting "some" console > backends). But it is based on KERN_$LOGLEVEL which is too rough-grained. IMHO, developers already have troubles to decide between the existing 8 loglevels. And it is easier because the names describe the severity. NO_CONSOLES would be different. The effect is almost[*] clear. But only few people would know the background why it was introduced and where to use it. I know that it is meant as a modifier, like LOGLEVEL_SCHED and KERN_CONT. But this is another reason to avoid it. We already have huge pain with these two modifiers. They both do not work well. [*] It will have no effect when it was disabled by a sysfs knob. Best Regards, Petr