From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754718AbeDTMEc (ORCPT ); Fri, 20 Apr 2018 08:04:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:52224 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754591AbeDTMEb (ORCPT ); Fri, 20 Apr 2018 08:04:31 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EFFF021104 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Fri, 20 Apr 2018 08:04:28 -0400 From: Steven Rostedt To: Petr Mladek Cc: Sergey Senozhatsky , akpm@linux-foundation.org, linux-mm@kvack.org, Peter Zijlstra , Jan Kara , Tetsuo Handa , Tejun Heo , linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: Re: [PATCH] printk: Ratelimit messages printed by console drivers Message-ID: <20180420080428.622a8e7f@gandalf.local.home> In-Reply-To: <20180420091224.cotxcfycmtt2hm4m@pathway.suse.cz> References: <20180413124704.19335-1-pmladek@suse.com> <20180413101233.0792ebf0@gandalf.local.home> <20180414023516.GA17806@tigerII.localdomain> <20180416014729.GB1034@jagdpanzerIV> <20180416042553.GA555@jagdpanzerIV> <20180419125353.lawdc3xna5oqlq7k@pathway.suse.cz> <20180420021511.GB6397@jagdpanzerIV> <20180420091224.cotxcfycmtt2hm4m@pathway.suse.cz> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Apr 2018 11:12:24 +0200 Petr Mladek wrote: > Yes, my number was arbitrary. The important thing is that it was long > enough. Or do you know about an console that will not be able to write > 100 lines within one hour? The problem is the way rate limit works. If you print 100 lines (or 1000) in 5 seconds, then you just stopped printing from that context for 59 minutes and 55 seconds. That's a long time to block printing. What happens if you had a couple of NMIs go off that takes up that time, and then you hit a bug 10 minutes later from that context. You just lost it. This is a magnitude larger than any other user of rate limit in the kernel. The most common time is 5 seconds. The longest I can find is 1 minute. You are saying you want to block printing from this context for 60 minutes! That is HUGE! I don't understand your rational for such a huge number. What data do you have to back that up with? -- Steve