From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751997AbeAWRWx (ORCPT ); Tue, 23 Jan 2018 12:22:53 -0500 Received: from mail-qt0-f196.google.com ([209.85.216.196]:38237 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751432AbeAWRWu (ORCPT ); Tue, 23 Jan 2018 12:22:50 -0500 X-Google-Smtp-Source: AH8x227hTA0nXjx+8Ogtw8gzcw05Fo72JS0UknH9ubD/EIGuRiXaK4uAqzYX/7Cix2Y16LIqBGhfzQ== Date: Tue, 23 Jan 2018 09:22:46 -0800 From: Tejun Heo To: Sergey Senozhatsky Cc: Steven Rostedt , Sergey Senozhatsky , Petr Mladek , akpm@linux-foundation.org, linux-mm@kvack.org, Cong Wang , Dave Hansen , Johannes Weiner , Mel Gorman , Michal Hocko , Vlastimil Babka , Peter Zijlstra , Linus Torvalds , Jan Kara , Mathieu Desnoyers , Tetsuo Handa , rostedt@rostedt.homelinux.com, Byungchul Park , Pavel Machek , linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup Message-ID: <20180123172246.GG1771050@devbig577.frc2.facebook.com> References: <20180117134201.0a9cbbbf@gandalf.local.home> <20180119132052.02b89626@gandalf.local.home> <20180120071402.GB8371@jagdpanzerIV> <20180120104931.1942483e@gandalf.local.home> <20180121141521.GA429@tigerII.localdomain> <20180123064023.GA492@jagdpanzerIV> <20180123095652.5e14da85@gandalf.local.home> <20180123152130.GB429@tigerII.localdomain> <20180123104121.2ef96d81@gandalf.local.home> <20180123160153.GC429@tigerII.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180123160153.GC429@tigerII.localdomain> 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 Hello, Sergey. On Wed, Jan 24, 2018 at 01:01:53AM +0900, Sergey Senozhatsky wrote: > On (01/23/18 10:41), Steven Rostedt wrote: > [..] > > We can have more. But if printk is causing printks, that's a major bug. > > And work queues are not going to fix it, it will just spread out the > > pain. Have it be 100 printks, it needs to be fixed if it is happening. > > And having all printks just generate more printks is not helpful. Even > > if we slow them down. They will still never end. > > Dropping the messages is not the solution either. The original bug report > report was - this "locks up my kernel". That's it. That's all people asked > us to solve. > > With WQ we don't lockup the kernel, because we flush printk_safe in > preemptible context. And people are very much expected to fix the > misbehaving consoles. But that should not be printk_safe problem. I really don't care as long as it's robust enough. Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f199.google.com (mail-qt0-f199.google.com [209.85.216.199]) by kanga.kvack.org (Postfix) with ESMTP id 52778800D8 for ; Tue, 23 Jan 2018 12:22:50 -0500 (EST) Received: by mail-qt0-f199.google.com with SMTP id k11so1543916qth.23 for ; Tue, 23 Jan 2018 09:22:50 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id a197sor12163990qkc.51.2018.01.23.09.22.49 for (Google Transport Security); Tue, 23 Jan 2018 09:22:49 -0800 (PST) Date: Tue, 23 Jan 2018 09:22:46 -0800 From: Tejun Heo Subject: Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup Message-ID: <20180123172246.GG1771050@devbig577.frc2.facebook.com> References: <20180117134201.0a9cbbbf@gandalf.local.home> <20180119132052.02b89626@gandalf.local.home> <20180120071402.GB8371@jagdpanzerIV> <20180120104931.1942483e@gandalf.local.home> <20180121141521.GA429@tigerII.localdomain> <20180123064023.GA492@jagdpanzerIV> <20180123095652.5e14da85@gandalf.local.home> <20180123152130.GB429@tigerII.localdomain> <20180123104121.2ef96d81@gandalf.local.home> <20180123160153.GC429@tigerII.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180123160153.GC429@tigerII.localdomain> Sender: owner-linux-mm@kvack.org List-ID: To: Sergey Senozhatsky Cc: Steven Rostedt , Sergey Senozhatsky , Petr Mladek , akpm@linux-foundation.org, linux-mm@kvack.org, Cong Wang , Dave Hansen , Johannes Weiner , Mel Gorman , Michal Hocko , Vlastimil Babka , Peter Zijlstra , Linus Torvalds , Jan Kara , Mathieu Desnoyers , Tetsuo Handa , rostedt@home.goodmis.org, Byungchul Park , Pavel Machek , linux-kernel@vger.kernel.org Hello, Sergey. On Wed, Jan 24, 2018 at 01:01:53AM +0900, Sergey Senozhatsky wrote: > On (01/23/18 10:41), Steven Rostedt wrote: > [..] > > We can have more. But if printk is causing printks, that's a major bug. > > And work queues are not going to fix it, it will just spread out the > > pain. Have it be 100 printks, it needs to be fixed if it is happening. > > And having all printks just generate more printks is not helpful. Even > > if we slow them down. They will still never end. > > Dropping the messages is not the solution either. The original bug report > report was - this "locks up my kernel". That's it. That's all people asked > us to solve. > > With WQ we don't lockup the kernel, because we flush printk_safe in > preemptible context. And people are very much expected to fix the > misbehaving consoles. But that should not be printk_safe problem. I really don't care as long as it's robust enough. 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