From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 773D3C004D3 for ; Mon, 22 Oct 2018 14:30:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F26620663 for ; Mon, 22 Oct 2018 14:30:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F26620663 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728320AbeJVWtV (ORCPT ); Mon, 22 Oct 2018 18:49:21 -0400 Received: from mx2.suse.de ([195.135.220.15]:58464 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727210AbeJVWtV (ORCPT ); Mon, 22 Oct 2018 18:49:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 16113B040; Mon, 22 Oct 2018 14:30:31 +0000 (UTC) Date: Mon, 22 Oct 2018 16:30:29 +0200 From: Petr Mladek To: Peter Zijlstra Cc: Sergey Senozhatsky , linux-kernel@vger.kernel.org, Steven Rostedt , Daniel Wang , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman , Alan Cox , Jiri Slaby , Peter Feiner , linux-serial@vger.kernel.org, Sergey Senozhatsky , john.ogness@linutronix.de Subject: Re: [RFC][PATCHv2 2/4] printk: move printk_safe macros to printk header Message-ID: <20181022143029.i4jc5vjq4t3tagb3@pathway.suse.cz> References: <20181016050428.17966-1-sergey.senozhatsky@gmail.com> <20181016050428.17966-3-sergey.senozhatsky@gmail.com> <20181016072719.GB4030@hirez.programming.kicks-ass.net> <20181016114006.6q5atyaitapcwbud@pathway.suse.cz> <20181016121752.GA2537@hirez.programming.kicks-ass.net> <20181017105015.udzegzfh7cxgatso@pathway.suse.cz> <20181017140044.GK3121@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181017140044.GK3121@hirez.programming.kicks-ass.net> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2018-10-17 16:00:44, Peter Zijlstra wrote: > On Wed, Oct 17, 2018 at 12:50:15PM +0200, Petr Mladek wrote: > > Also note that by deferred printk I mean deferring the console > > handling! IMHO, there are _no more problems_ with storing > > the messages into the buffer if we accept that the current > > very limited use of printk_safe per-cpu buffers is easier > > than any complicated generic lockless buffer. > > They hide messages. The whole two radically different printk paths is > also quite horrible. I agree that having everything in one buffer with unified and safe access from any context would be a great win. > And lockless buffers aren't all _that_ complicated, esp. not when > performance isn't the top priority. > > And earlycon is mostly usable, esp. the serial ones. Those, when > configured, should synchronously print along. The current design > also makes that difficult. > > A wee little like so; typed in a hurry, never been near a compiler. Thanks a lot for the code. I still need to find time to better understand it. Anyway, it looks worth considering. Best Regards, Petr