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[209.132.180.67]) by mx.google.com with ESMTP id j35si2704703eda.144.2019.09.17.16.36.20; Tue, 17 Sep 2019 16:36:43 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726958AbfIQOId (ORCPT + 99 others); Tue, 17 Sep 2019 10:08:33 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:63688 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726404AbfIQOIc (ORCPT ); Tue, 17 Sep 2019 10:08:32 -0400 Received: from fsav401.sakura.ne.jp (fsav401.sakura.ne.jp [133.242.250.100]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id x8HE8U4p034336; Tue, 17 Sep 2019 23:08:30 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav401.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav401.sakura.ne.jp); Tue, 17 Sep 2019 23:08:30 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav401.sakura.ne.jp) Received: from [192.168.1.8] (softbank126227201116.bbtec.net [126.227.201.116]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id x8HE8L0G034277 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NO); Tue, 17 Sep 2019 23:08:29 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: printk meeting at LPC To: Steven Rostedt , Greg Kroah-Hartman Cc: Petr Mladek , Daniel Vetter , AndreaParri , Sergey Senozhatsky , Sergey Senozhatsky , Brendan Higgins , Paul Turner , Peter Zijlstra , John Ogness , Thomas Gleixner , LinusTorvalds , "Theodore Ts'o" , PraritBhargava , LKML References: <20190905143118.GP2349@hirez.programming.kicks-ass.net> <20190905121101.60c78422@oasis.local.home> <87k1acz5rx.fsf@linutronix.de> <20190916104624.n3jh363z37ah2kxa@pathway.suse.cz> <20190916094314.6053f988@gandalf.local.home> <20190917075216.agzoy6cnol5eio6y@pathway.suse.cz> <20190917090254.46131564@gandalf.local.home> <20190917131204.GA745680@kroah.com> <20190917093720.51977128@gandalf.local.home> From: Tetsuo Handa Message-ID: Date: Tue, 17 Sep 2019 23:08:21 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20190917093720.51977128@gandalf.local.home> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/09/17 22:37, Steven Rostedt wrote: > On Tue, 17 Sep 2019 15:12:04 +0200 > Greg Kroah-Hartman wrote: > >>> Well, it's being used. I was thinking of dropping it if it was not. >>> Let's keep it then. >> >> I think it should be dropped, only one user of the kernel is using it in >> a legitimate way, which kind of implies it isn't needed. > > I'm thinking if it isn't hard to support then we can keep it (meaning > that we already have to calculate the length anyway). But if it starts > to complicate the code, then we should drop it. > Due to console_loglevel (some are printed and others are not printed) and possibility of concurrent printk() callers (one line can be printed as multiple lines), using printk()'s return value for calculating column offset will not always work as expected. I guess that users should not count on printk()'s return value. They might want to try printing one line at a time using their local buffers...