From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754220AbaIPPNh (ORCPT ); Tue, 16 Sep 2014 11:13:37 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.227]:27291 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753836AbaIPPNg (ORCPT ); Tue, 16 Sep 2014 11:13:36 -0400 Date: Tue, 16 Sep 2014 11:13:31 -0400 From: Steven Rostedt To: Markus Trippelsdorf Cc: Jan Kara , Geert Uytterhoeven , "linux-kernel@vger.kernel.org" , Andrew Morton , Peter Zijlstra Subject: Re: [PATCH] printk: git rid of [sched_delayed] message for printk_deferred Message-ID: <20140916111331.14303381@gandalf.local.home> In-Reply-To: <20140916144252.GB32118@x4> References: <20140914050905.GA296@x4> <20140914055450.GB296@x4> <20140915163740.GA12408@x4> <20140916105547.GA1205@quack.suse.cz> <20140916144252.GB32118@x4> X-Mailer: Claws Mail 3.10.1 (GTK+ 2.24.24; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.130:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Sep 2014 16:42:52 +0200 Markus Trippelsdorf wrote: > commit 458df9fd hardcodes printk_deferred() to KERN_WARNING and inserts > the string "[sched_delayed] " before the actual message. > However it doesn't take into account the KERN_* prefix of the message, > that now ends up in the middle of the output: > > [sched_delayed] ^a4CE: hpet increased min_delta_ns to 20115 nsec > > Fix this by just getting rid of the "[sched_delayed] " scnprintf(). I prefer the "[sched_delayed]" output. It lets us know that the output did not come out immediately, which is important sometimes during debugging. Otherwise it can confuse people, as printk is suppose to be a blocking write. Can we instead fix the bug instead of nuking the output? That is, move the KERN_* prefix before the "[sched_delayed]" message? I don't think it would be that hard. If you want, I'll write that patch (probably take me 20 minutes at most), but I'm just coming back from medical leave so I prefer not to. -- Steve > > Acked-by: Jan Kara > Signed-off-by: Markus Trippelsdorf > > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > index 1ce770687ea8..f85994b58934 100644 > --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -1680,12 +1680,7 @@ asmlinkage int vprintk_emit(int facility, int level, > * The printf needs to come first; we need the syslog > * prefix which might be passed-in as a parameter. > */ > - if (in_sched) > - text_len = scnprintf(text, sizeof(textbuf), > - KERN_WARNING "[sched_delayed] "); > - > - text_len += vscnprintf(text + text_len, > - sizeof(textbuf) - text_len, fmt, args); > + text_len = vscnprintf(text, sizeof(textbuf), fmt, args); > > /* mark and strip a trailing newline */ > if (text_len && text[text_len-1] == '\n') {