From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932274AbZKXIjq (ORCPT ); Tue, 24 Nov 2009 03:39:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932249AbZKXIjp (ORCPT ); Tue, 24 Nov 2009 03:39:45 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:39770 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932247AbZKXIjo (ORCPT ); Tue, 24 Nov 2009 03:39:44 -0500 Subject: Re: [PATCH] irq: Add node_affinity CPU masks for smarter irqbalance hints From: Peter Zijlstra To: Arjan van de Ven Cc: Peter P Waskiewicz Jr , Yong Zhang , "linux-kernel@vger.kernel.org" , "arjan@linux.jf.intel.com" , "davem@davemloft.net" , "netdev@vger.kernel.org" In-Reply-To: <4B0B782A.4030901@linux.intel.com> References: <20091123064630.7385.30498.stgit@ppwaskie-hc2.jf.intel.com> <2674af740911222332i65c0d066h79bf2c1ca1d5e4f0@mail.gmail.com> <1258968980.2697.9.camel@ppwaskie-mobl2> <1258995923.4531.715.camel@laptop> <4B0B782A.4030901@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 24 Nov 2009 09:39:46 +0100 Message-ID: <1259051986.4531.1057.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2009-11-23 at 22:07 -0800, Arjan van de Ven wrote: > Peter Zijlstra wrote: > > On Mon, 2009-11-23 at 01:36 -0800, Peter P Waskiewicz Jr wrote: > > > >> This mechanism isn't going to be used by any internal kernel mechanism > >> for determining interrupt placement or operation. It's purely something > >> that either a driver can modify, or external script (through /proc), > >> that irqbalance will make use of. If irqbalance isn't running, or the > >> current version of irqbalance doesn't support reading node_affinity, > >> then it won't affect the system's operation. > >> > >> If irqbalance does support it, it'll read whatever the supplied mask is, > >> and then will try and balance interrupts within that mask. It will bail > >> if the mask is invalid, or won't apply to the running system, just like > >> how putting a bogus mask into smp_affinity is ignored. > >> > >> If there's something I'm missing beyond this with the two suggestions > >> you've made (I looked into those two parameters and tried to draw > >> conclusions), please let me know. > > > > I don't see the point in adding it, if the driver wants to set a node > > cpu mask it can already do that using the regular smp affinity settings. > > > > Same for userspace. > > the problem is that there is no way currently that the driver can communicate > "I allocated all my metadata on THIS numa node". irqbalance and sysadmins need > that to not make really stupid decisions..... And what exactly is struct device::numa_node good for then?