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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5108C433FE for ; Mon, 14 Feb 2022 10:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348615AbiBNKjH (ORCPT ); Mon, 14 Feb 2022 05:39:07 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:49168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348856AbiBNKgB (ORCPT ); Mon, 14 Feb 2022 05:36:01 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 534C2205D4 for ; Mon, 14 Feb 2022 02:02:21 -0800 (PST) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 0D41E210F4; Mon, 14 Feb 2022 10:02:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1644832940; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5mCqPoiiSFqVsEsSBkh61HkdEnJ7cMxylRwFu11LaQA=; b=OzueHF+cFHoaypaGmaasoI+PnOp34/rRlN6Qiq2/lo8bgGwlYqrOAPjoIKt+rDBmOgDlty Ek+RRwmKgEl56VXke2AvkLvUuwBZOWgglmy3NCIGpcAF5x1WraV2cQQobQTag2v15fjjEU HJJOhafFQFWPy+ScYqd/Oe71/GxR3Z4= Received: from suse.cz (unknown [10.100.216.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 81597A3B8E; Mon, 14 Feb 2022 10:02:19 +0000 (UTC) Date: Mon, 14 Feb 2022 11:02:19 +0100 From: Petr Mladek To: Sergey Senozhatsky Cc: John Ogness , Hillf Danton , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Steven Rostedt Subject: Re: [PATCH printk v1 10/13] printk: add kthread console printers Message-ID: References: <20220207194323.273637-1-john.ogness@linutronix.de> <20220208083620.2736-1-hdanton@sina.com> <87v8xpmx9n.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 2022-02-14 15:12:51, Sergey Senozhatsky wrote: > On (22/02/08 15:53), Petr Mladek wrote: > > My mine concern is that the kthread_worker API still uses an internal > > lock. And it is yet another layer that might be hard to debug when > > printk() does not work. > > Isn't this also true for kthreads? Looks like we add "couple of spin_locks" > to the picture - rq, etc. - one way of the other. kthread_worker API is built on top of kthreads. It means one more lock, one more layer to deal with. If anyone wants to propose workqueues or kthread_worker API, please, come up with a code and proof that it makes things easier. It is fine to mention this possibility. It is fine to consider it. It is fine to keep it in mind. But I do not want to spent too much time on theoretic discussions at the moment. We have a code now. John has spent non-trivial time on it. Let's concentrate on review. Best Regards, Petr