From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751642AbeAJTGC (ORCPT + 1 other); Wed, 10 Jan 2018 14:06:02 -0500 Received: from mail-qk0-f179.google.com ([209.85.220.179]:36947 "EHLO mail-qk0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750861AbeAJTGB (ORCPT ); Wed, 10 Jan 2018 14:06:01 -0500 X-Google-Smtp-Source: ACJfBotrld/7qRW2Ts2agDCX5GbfAP4khpoYjun22+m6JKJJwIq9laFPW/BQSM7Wr+uElCh+c+Rccw== Date: Wed, 10 Jan 2018 11:05:57 -0800 From: Tejun Heo To: Peter Zijlstra Cc: Petr Mladek , Linus Torvalds , akpm@linux-foundation.org, Steven Rostedt , Sergey Senozhatsky , linux-mm@kvack.org, Cong Wang , Dave Hansen , Johannes Weiner , Mel Gorman , Michal Hocko , Vlastimil Babka , Jan Kara , Mathieu Desnoyers , Tetsuo Handa , rostedt@home.goodmis.org, Byungchul Park , Sergey Senozhatsky , Pavel Machek , linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup Message-ID: <20180110190557.GA3460072@devbig577.frc2.facebook.com> References: <20180110132418.7080-1-pmladek@suse.com> <20180110140547.GZ3668920@devbig577.frc2.facebook.com> <20180110162900.GA21753@linux.suse> <20180110170223.GF3668920@devbig577.frc2.facebook.com> <20180110182153.GP6176@hirez.programming.kicks-ass.net> <20180110183055.GM3668920@devbig577.frc2.facebook.com> <20180110184144.GR6176@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180110184144.GR6176@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hello, On Wed, Jan 10, 2018 at 07:41:44PM +0100, Peter Zijlstra wrote: > Typically we (scheduler) have removed printk()s (on boot) when BIGSMP > folks say it creates boot pain. Much of it is now behind the sched_debug > parameter, others are compressed. > > I've also seen other people reduce printk()s. > > In general reducing printk() is a good thing, its a low bandwidth > channel for critical stuff like OOPSen and the like. Yeah, sure, no disagreement there. It's just that this is a provision for when that breaks down. In the described scenario, it's also not caused by any particular one printing too many messages. OOM is just printing OOM info and packet tx is just printing standard alloc failed message (and some other following errors). It's the feedback loop which kills the machine. Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f200.google.com (mail-qk0-f200.google.com [209.85.220.200]) by kanga.kvack.org (Postfix) with ESMTP id 9CFAB6B0033 for ; Wed, 10 Jan 2018 14:06:01 -0500 (EST) Received: by mail-qk0-f200.google.com with SMTP id d125so58003qkb.8 for ; Wed, 10 Jan 2018 11:06:01 -0800 (PST) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id v47sor12044684qtj.37.2018.01.10.11.06.00 for (Google Transport Security); Wed, 10 Jan 2018 11:06:00 -0800 (PST) Date: Wed, 10 Jan 2018 11:05:57 -0800 From: Tejun Heo Subject: Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup Message-ID: <20180110190557.GA3460072@devbig577.frc2.facebook.com> References: <20180110132418.7080-1-pmladek@suse.com> <20180110140547.GZ3668920@devbig577.frc2.facebook.com> <20180110162900.GA21753@linux.suse> <20180110170223.GF3668920@devbig577.frc2.facebook.com> <20180110182153.GP6176@hirez.programming.kicks-ass.net> <20180110183055.GM3668920@devbig577.frc2.facebook.com> <20180110184144.GR6176@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180110184144.GR6176@hirez.programming.kicks-ass.net> Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Petr Mladek , Linus Torvalds , akpm@linux-foundation.org, Steven Rostedt , Sergey Senozhatsky , linux-mm@kvack.org, Cong Wang , Dave Hansen , Johannes Weiner , Mel Gorman , Michal Hocko , Vlastimil Babka , Jan Kara , Mathieu Desnoyers , Tetsuo Handa , rostedt@home.goodmis.org, Byungchul Park , Sergey Senozhatsky , Pavel Machek , linux-kernel@vger.kernel.org Hello, On Wed, Jan 10, 2018 at 07:41:44PM +0100, Peter Zijlstra wrote: > Typically we (scheduler) have removed printk()s (on boot) when BIGSMP > folks say it creates boot pain. Much of it is now behind the sched_debug > parameter, others are compressed. > > I've also seen other people reduce printk()s. > > In general reducing printk() is a good thing, its a low bandwidth > channel for critical stuff like OOPSen and the like. Yeah, sure, no disagreement there. It's just that this is a provision for when that breaks down. In the described scenario, it's also not caused by any particular one printing too many messages. OOM is just printing OOM info and packet tx is just printing standard alloc failed message (and some other following errors). It's the feedback loop which kills the machine. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org