From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754756AbcI2NZL (ORCPT ); Thu, 29 Sep 2016 09:25:11 -0400 Received: from mx2.suse.de ([195.135.220.15]:56074 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751702AbcI2NZE (ORCPT ); Thu, 29 Sep 2016 09:25:04 -0400 Date: Thu, 29 Sep 2016 15:25:02 +0200 From: Petr Mladek To: Sergey Senozhatsky Cc: Jan Kara , Andrew Morton , Tejun Heo , Calvin Owens , linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: Re: [RFC][PATCH 0/7] printk: use alt_printk to handle printk() recursive calls Message-ID: <20160929132502.GG26796@pathway.suse.cz> References: <20160927142237.5539-1-sergey.senozhatsky@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160927142237.5539-1-sergey.senozhatsky@gmail.com> 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 Tue 2016-09-27 23:22:30, Sergey Senozhatsky wrote: > Hello, > > RFC > > This patch set extends a lock-less NMI per-cpu buffers idea to > handle recursive printk() calls. The basic mechanism is pretty much the > same -- at the beginning of a deadlock-prone section we switch to lock-less > printk callback, and return back to a default printk implementation at the > end; the messages are getting flushed to a logbuf buffer from a safer > context. I was skeptical but I really like this way now. The switching of the buffers is a bit hairy in this version but I think that we could make it much better. Other than that it looks like a big win. It kills a lot of printk-related pain points. And it will not be that complicated after all. Best Regards, Petr