From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753394AbcCGPt4 (ORCPT ); Mon, 7 Mar 2016 10:49:56 -0500 Received: from mail-yw0-f194.google.com ([209.85.161.194]:33499 "EHLO mail-yw0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752840AbcCGPtj (ORCPT ); Mon, 7 Mar 2016 10:49:39 -0500 Date: Mon, 7 Mar 2016 10:49:36 -0500 From: Tejun Heo To: Sergey Senozhatsky Cc: Jan Kara , Sergey Senozhatsky , Tetsuo Handa , akpm@linux-foundation.org, jack@suse.com, pmladek@suse.com, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Message-ID: <20160307154936.GB7065@htj.duckdns.org> References: <20160306063251.GA493@swordfish> <201603061618.GED43232.MtOQOFSLOFHJFV@I-love.SAKURA.ne.jp> <20160306093530.GA26055@swordfish> <201603062006.IJD17667.OOQFLtMVHOFSJF@I-love.SAKURA.ne.jp> <20160306132703.GA927@swordfish> <20160307082230.GB5201@quack.suse.cz> <20160307101233.GA10690@swordfish> <20160307105248.GF5201@quack.suse.cz> <20160307121625.GG5201@quack.suse.cz> <20160307151047.GA578@swordfish> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160307151047.GA578@swordfish> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, Mar 08, 2016 at 12:10:47AM +0900, Sergey Senozhatsky wrote: > A new version. Switched to [printk] kthread. There are some benefits to using a percpu workqueue with CPU_INTENSIVE set or an unbound workqueue. It'd need WQ_RESCUER so it'd still create a dedicated thread which is used under heavy memory pressure but workqueue will usaully give you local (cpu or node) worker. One reason to use kthread directly tho is minimizing the amount of dependency which is pretty important for printk. If we decide to use kthread instead of workqueue, let's please do it for the right reason. Thanks. -- tejun