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 EB565C433DF for ; Thu, 20 Aug 2020 07:44:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA976207DE for ; Thu, 20 Aug 2020 07:44:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726735AbgHTHo3 convert rfc822-to-8bit (ORCPT ); Thu, 20 Aug 2020 03:44:29 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:52664 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725797AbgHTHo3 (ORCPT ); Thu, 20 Aug 2020 03:44:29 -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-79-EZQzNz_MMTW5m19NmXdomw-1; Thu, 20 Aug 2020 08:44:24 +0100 X-MC-Unique: EZQzNz_MMTW5m19NmXdomw-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 08:44:23 +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 08:44:23 +0100 From: David Laight To: 'Joe Perches' , John Ogness , Linus Torvalds CC: Petr Mladek , 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: AQHWdomYXzVvufyPxEOt+PNltcCbQKlAmzJg Date: Thu, 20 Aug 2020 07:44:23 +0000 Message-ID: References: <20200819232632.13418-1-john.ogness@linutronix.de> <20200819232632.13418-2-john.ogness@linutronix.de> In-Reply-To: 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: Joe Perches > Sent: 20 August 2020 01:34 > > On Thu, 2020-08-20 at 01:32 +0206, John Ogness wrote: > > Implement a new buffering mechanism for pr_cont messages. > > > > Old mechanism syntax: > > > > printk(KERN_INFO "text"); > > printk(KERN_CONT " continued"); > > printk(KERN_CONT "\n"); > > > > New mechanism syntax: > > > > pr_cont_t c; > > > > pr_cont_begin(&c, KERN_INFO "text"); > > bikeshed: > > I suggest: > > printk_begin(&printk_context, fmt, ...) > printk_continue(&printk_context, fmt, ...) (maybe printk_next()) > printk_end(&printk_context, fmt, ...) I see some very long source lines looming ... Blue bikeshed: You'd probably want printk_end(&ctx, NULL) to work. Although the example doesn't show where the '\n' comes from. Although I guess it is now inferred and actually deleted from 'normal' printk() call. I've no idea how you'd 'size' the number of buffers. You could use kmalloc(), perhaps falling back on a local buffer. While might lead to: pr_init(&ctx, level, GFP_KERNEL); pr_cont(&ctx, fmt, ...); pr_flush(&ctx); David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)