From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750933AbeAPFXI (ORCPT + 1 other); Tue, 16 Jan 2018 00:23:08 -0500 Received: from mail-pf0-f194.google.com ([209.85.192.194]:45566 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750765AbeAPFXG (ORCPT ); Tue, 16 Jan 2018 00:23:06 -0500 X-Google-Smtp-Source: ACJfBotgPJXacTvT07gAAEgvhxQ9UUqo0JHLxO9nj6B2FL7hBrOLvvFXi0mqhPNb2DFfnQQhTRChFA== Date: Tue, 16 Jan 2018 14:23:01 +0900 From: Sergey Senozhatsky To: Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Sergey Senozhatsky , Tejun Heo , 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 Subject: Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup Message-ID: <20180116052301.GC13731@jagdpanzerIV> References: <20180111045817.GA494@jagdpanzerIV> <20180111093435.GA24497@linux.suse> <20180111103845.GB477@jagdpanzerIV> <20180111112908.50de440a@vmware.local.home> <20180112025612.GB6419@jagdpanzerIV> <20180111222140.7fd89d52@gandalf.local.home> <20180112100544.GA441@jagdpanzerIV> <20180112072123.33bb567d@gandalf.local.home> <20180113072834.GA1701@tigerII.localdomain> <20180115101743.qh5whicsn6hmac32@pathway.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180115101743.qh5whicsn6hmac32@pathway.suse.cz> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hi, On (01/15/18 11:17), Petr Mladek wrote: > Hi Sergey, > > I wonder if there is still some miss understanding. > > Steven and me are trying to get this patch in because we believe > that it is a step forward. We know that it is not perfect. But > we believe that it makes things better. In particular, it limits > the time spent in console_unlock() in atomic context. It does > not make it worse in preemptible context. > > It does not block further improvements, including offloading > to the kthread. We will happily discuss and review further > improvements, it they prove to be necessary. > > The advantage of this approach is that it is incremental. It should > be easier for review and analyzing possible regressions. > > What is the aim of your mails, please? > Do you want to say that this patch might cause regressions? > Or do you want to say that it does not solve all scenarios? > > Please, answer the above questions. I am still confused. I ACK-ed the patch set, given that I hope that we at least will do (a) a) remove preemption out of printk()->user critical path --- b) the next thing would be - O(logbuf) is not a good boundary c) the thing after that would be to - O(logbuf) boundary can be broken in both preemptible and non-preemptible contexts. but (b) and (c) can wait. -ss From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71]) by kanga.kvack.org (Postfix) with ESMTP id C331A6B0038 for ; Tue, 16 Jan 2018 00:23:07 -0500 (EST) Received: by mail-pl0-f71.google.com with SMTP id w23so1136781plk.5 for ; Mon, 15 Jan 2018 21:23:07 -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 r16sor291079pfh.69.2018.01.15.21.23.06 for (Google Transport Security); Mon, 15 Jan 2018 21:23:06 -0800 (PST) Date: Tue, 16 Jan 2018 14:23:01 +0900 From: Sergey Senozhatsky Subject: Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup Message-ID: <20180116052301.GC13731@jagdpanzerIV> References: <20180111045817.GA494@jagdpanzerIV> <20180111093435.GA24497@linux.suse> <20180111103845.GB477@jagdpanzerIV> <20180111112908.50de440a@vmware.local.home> <20180112025612.GB6419@jagdpanzerIV> <20180111222140.7fd89d52@gandalf.local.home> <20180112100544.GA441@jagdpanzerIV> <20180112072123.33bb567d@gandalf.local.home> <20180113072834.GA1701@tigerII.localdomain> <20180115101743.qh5whicsn6hmac32@pathway.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180115101743.qh5whicsn6hmac32@pathway.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Sergey Senozhatsky , Tejun Heo , 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 Hi, On (01/15/18 11:17), Petr Mladek wrote: > Hi Sergey, > > I wonder if there is still some miss understanding. > > Steven and me are trying to get this patch in because we believe > that it is a step forward. We know that it is not perfect. But > we believe that it makes things better. In particular, it limits > the time spent in console_unlock() in atomic context. It does > not make it worse in preemptible context. > > It does not block further improvements, including offloading > to the kthread. We will happily discuss and review further > improvements, it they prove to be necessary. > > The advantage of this approach is that it is incremental. It should > be easier for review and analyzing possible regressions. > > What is the aim of your mails, please? > Do you want to say that this patch might cause regressions? > Or do you want to say that it does not solve all scenarios? > > Please, answer the above questions. I am still confused. I ACK-ed the patch set, given that I hope that we at least will do (a) a) remove preemption out of printk()->user critical path --- b) the next thing would be - O(logbuf) is not a good boundary c) the thing after that would be to - O(logbuf) boundary can be broken in both preemptible and non-preemptible contexts. but (b) and (c) can wait. -ss -- 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