From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755851AbaCZRXx (ORCPT ); Wed, 26 Mar 2014 13:23:53 -0400 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:50620 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755577AbaCZRXq (ORCPT ); Wed, 26 Mar 2014 13:23:46 -0400 Date: Wed, 26 Mar 2014 17:23:32 +0000 From: One Thousand Gnomes To: Jan Kara Cc: Andrew Morton , LKML , pmladek@suse.cz, Frederic Weisbecker , Steven Rostedt Subject: Re: [PATCH 8/8] printk: Add config option for disabling printk offloading Message-ID: <20140326172332.5f1e1bfb@alan.etchedpixels.co.uk> In-Reply-To: <1395770101-24534-9-git-send-email-jack@suse.cz> References: <1395770101-24534-1-git-send-email-jack@suse.cz> <1395770101-24534-9-git-send-email-jack@suse.cz> Organization: Intel Corporation X-Mailer: Claws Mail 3.8.1 (GTK+ 2.24.20; 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 Tue, 25 Mar 2014 18:55:01 +0100 Jan Kara wrote: > Necessity for offloading of printing was observed only for large > systems. So add a config option (disabled by default) which removes most > of the overhead added by this functionality. If its an option it'll not get used. It ought to be automatic. I still think the mindset of this patch set is wrong. Only the device driver really knows what is good or bad. A large x86 connected to a network fake 16x50 serial port for example typically has a giant FIFO so 'bad' becomes 32K not 1000. A USB serial port already does async queueing so the value is 0. It also ignores priority so you might queue and loose an oops as a box goes down in preference to reporting debugging crap. All the afflicted consoles are serial, all go via the uart layer as far as I can see. The uart layer has a queue mechanism that could be used Alan