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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 3153AC433E1 for ; Thu, 20 Aug 2020 12:33:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0780E20738 for ; Thu, 20 Aug 2020 12:33:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729800AbgHTMdd convert rfc822-to-8bit (ORCPT ); Thu, 20 Aug 2020 08:33:33 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:27665 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729745AbgHTMd2 (ORCPT ); Thu, 20 Aug 2020 08:33:28 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-193-nhtq2MljN_maCPHdjtnu_A-1; Thu, 20 Aug 2020 13:33:23 +0100 X-MC-Unique: nhtq2MljN_maCPHdjtnu_A-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 20 Aug 2020 13:33:23 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Thu, 20 Aug 2020 13:33:23 +0100 From: David Laight To: 'Petr Mladek' , John Ogness CC: Linus Torvalds , Sergey Senozhatsky , Steven Rostedt , Greg Kroah-Hartman , Thomas Gleixner , Sergey Senozhatsky , "linux-kernel@vger.kernel.org" Subject: RE: [RFC PATCH 1/5] printk: implement pr_cont_t Thread-Topic: [RFC PATCH 1/5] printk: implement pr_cont_t Thread-Index: AQHWdtr1XzVvufyPxEOt+PNltcCbQKlA7OUQ Date: Thu, 20 Aug 2020 12:33:23 +0000 Message-ID: References: <20200819232632.13418-1-john.ogness@linutronix.de> <20200819232632.13418-2-john.ogness@linutronix.de> <20200820101625.GE4353@alley> In-Reply-To: <20200820101625.GE4353@alley> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Petr Mladek > Sent: 20 August 2020 11:16 ... > Now that I think about it. This is the biggest problem with any temporary buffer > for pr_cont() lines. I am more and more convinced that we should just > _keep the current behavior_. It is not ideal. But sometimes mixed > messages are always better than lost ones. Maybe a marker to say 'more expected' might be useful. OTOH lack of a trailing '\n' probably signifies that a pr_cont() is likely to be next. Unexpected pr_cont() could be output with a leading "... " to help indicate the message is a continuation. > That said, some printk() API using local buffer would be still > valuable for pieces of code where people really want to avoid > mixed lines. But it should be optional and people should be > aware of the risks. That could be very useful if it supported multi-line output. Thing like the stack backtrace code could use it avoid the mess that happens when multiple processes generate tracebacks at the same time. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)