From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx153.postini.com [74.125.245.153]) by kanga.kvack.org (Postfix) with SMTP id 1C0926B00C1 for ; Thu, 6 Dec 2012 13:19:39 -0500 (EST) Message-ID: <50C0E1B6.5060602@fusionio.com> Date: Thu, 6 Dec 2012 19:19:34 +0100 From: Jens Axboe MIME-Version: 1.0 Subject: Re: [patch,v2] bdi: add a user-tunable cpu_list for the bdi flusher threads References: <50BE5988.3050501@fusionio.com> <50BE5C99.6070703@fusionio.com> <20121206180150.GQ19802@htj.dyndns.org> In-Reply-To: <20121206180150.GQ19802@htj.dyndns.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Jeff Moyer , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Zach Brown , Peter Zijlstra , Ingo On 2012-12-06 19:01, Tejun Heo wrote: > As for the original patch, I think it's a bit too much to expose to > userland. It's probably a good idea to bind the flusher to the local > node but do we really need to expose an interface to let userland > control the affinity directly? Do we actually have a use case at > hand? We need to expose it. Once the binding is set from the kernel side on a kernel thread, it can't be modified. Binding either for performance reasons or for ensuring that we explicitly don't run in some places is a very useful feature. -- Jens Axboe -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752695Ab2LFSTk (ORCPT ); Thu, 6 Dec 2012 13:19:40 -0500 Received: from mx2.fusionio.com ([66.114.96.31]:49653 "EHLO mx2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704Ab2LFSTi (ORCPT ); Thu, 6 Dec 2012 13:19:38 -0500 X-ASG-Debug-ID: 1354817977-0421b52b7d671a0001-xx1T2L X-Barracuda-Envelope-From: JAxboe@fusionio.com Message-ID: <50C0E1B6.5060602@fusionio.com> Date: Thu, 6 Dec 2012 19:19:34 +0100 From: Jens Axboe MIME-Version: 1.0 To: Tejun Heo CC: Jeff Moyer , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Zach Brown , Peter Zijlstra , Ingo Subject: Re: [patch,v2] bdi: add a user-tunable cpu_list for the bdi flusher threads References: <50BE5988.3050501@fusionio.com> <50BE5C99.6070703@fusionio.com> <20121206180150.GQ19802@htj.dyndns.org> X-ASG-Orig-Subj: Re: [patch,v2] bdi: add a user-tunable cpu_list for the bdi flusher threads In-Reply-To: <20121206180150.GQ19802@htj.dyndns.org> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Barracuda-Connect: mail1.int.fusionio.com[10.101.1.21] X-Barracuda-Start-Time: 1354817977 X-Barracuda-Encrypted: AES128-SHA X-Barracuda-URL: http://10.101.1.181:8000/cgi-mod/mark.cgi X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.2.116268 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2012-12-06 19:01, Tejun Heo wrote: > As for the original patch, I think it's a bit too much to expose to > userland. It's probably a good idea to bind the flusher to the local > node but do we really need to expose an interface to let userland > control the affinity directly? Do we actually have a use case at > hand? We need to expose it. Once the binding is set from the kernel side on a kernel thread, it can't be modified. Binding either for performance reasons or for ensuring that we explicitly don't run in some places is a very useful feature. -- Jens Axboe