From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757597AbbJVNTe (ORCPT ); Thu, 22 Oct 2015 09:19:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38334 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757137AbbJVNTb (ORCPT ); Thu, 22 Oct 2015 09:19:31 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20151022123036.GB2599@pathway.suse.cz> References: <20151022123036.GB2599@pathway.suse.cz> <20151022101650.25995.95155.stgit@warthog.procyon.org.uk> To: Petr Mladek Cc: dhowells@redhat.com, linux-kernel@vger.kernel.org, jack@suse.cz, will.deacon@arm.com, rostedt@goodmis.org, dwmw2@infradead.org, Andrew Morton Subject: Re: [PATCH] printk: Don't discard earlier unprinted messages to make space MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <482.1445519966.1@warthog.procyon.org.uk> Date: Thu, 22 Oct 2015 14:19:26 +0100 Message-ID: <483.1445519966@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Petr Mladek wrote: > I would expect that the first few messages are printed to the console > before the buffer is wrapped. IMHO, in many cases, you are interested > into the final messages that describe why the system went down. The last message might tell you that the machine panicked because the NMI handler triggered due to a spinlocked section taking too long or something. This doesn't help if the oops that caused the spinlock to remain held or whatever gets discarded from the buffer due to several intervening complaints that result secondarily from the initial oops. > If there is no time to print them, you want to have them in the crash dump > (ring buffer) at least. But not at the expense of discarding the first oops report. *That* one is the most important. Perhaps things could be arranged such that messages *can* be discarded from the front of the buffer *provided* they are not oops messages. David