From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964837Ab2LFSWr (ORCPT ); Thu, 6 Dec 2012 13:22:47 -0500 Received: from mail-da0-f46.google.com ([209.85.210.46]:59782 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755280Ab2LFSWp (ORCPT ); Thu, 6 Dec 2012 13:22:45 -0500 Date: Thu, 6 Dec 2012 10:22:39 -0800 From: Tejun Heo To: Jens Axboe 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 Message-ID: <20121206182239.GS19802@htj.dyndns.org> References: <50BE5988.3050501@fusionio.com> <50BE5C99.6070703@fusionio.com> <20121206180150.GQ19802@htj.dyndns.org> <50C0E1B6.5060602@fusionio.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50C0E1B6.5060602@fusionio.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 Hello, Jens. On Thu, Dec 06, 2012 at 07:19:34PM +0100, Jens Axboe wrote: > We need to expose it. Once the binding is set from the kernel side on a > kernel thread, it can't be modified. That's only if kthread_bind() is used. Caling set_cpus_allowed_ptr() doesn't set PF_THREAD_BOUND and userland can adjust affinity like any other tasks. > Binding either for performance reasons or for ensuring that we > explicitly don't run in some places is a very useful feature. Sure, but I think this is too specific. Something more generic would be much better. It can be as simple as generating a uevent. Thanks. -- tejun