From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757130Ab3KHKVS (ORCPT ); Fri, 8 Nov 2013 05:21:18 -0500 Received: from cantor2.suse.de ([195.135.220.15]:36843 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757086Ab3KHKVP (ORCPT ); Fri, 8 Nov 2013 05:21:15 -0500 Date: Fri, 8 Nov 2013 11:21:13 +0100 From: Jan Kara To: Frederic Weisbecker Cc: Steven Rostedt , Jan Kara , Andrew Morton , LKML , Michal Hocko Subject: Re: [PATCH 3/4] printk: Defer printing to irq work when we printed too much Message-ID: <20131108102113.GB6343@quack.suse.cz> References: <1383860919-1883-1-git-send-email-jack@suse.cz> <1383860919-1883-4-git-send-email-jack@suse.cz> <20131107225733.GE2054@quack.suse.cz> <20131107232148.GE28130@localhost.localdomain> <20131107183717.0fc9eb6e@gandalf.local.home> <20131107234647.GG28130@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131107234647.GG28130@localhost.localdomain> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 08-11-13 00:46:49, Frederic Weisbecker wrote: > On Thu, Nov 07, 2013 at 06:37:17PM -0500, Steven Rostedt wrote: > > On Fri, 8 Nov 2013 00:21:51 +0100 > > Frederic Weisbecker wrote: > > > > > > Offloading to a workqueue would be perhaps better, and writing to the serial > > > console could then be done with interrupts enabled, preemptible context, etc... > > > > Oh God no ;-) Adding workqueue logic into printk just spells a > > nightmare of much more complexity for a critical kernel infrastructure. > > But yeah that's scary, that means workqueues itself can't printk that safely. > So, you're right after all. Yeah, we've been there (that was actually my initial proposal). But Andrew and Steven (rightfully) objected and suggested irq_work should be used instead. Honza -- Jan Kara SUSE Labs, CR