Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757463AbZKXGHe (ORCPT ); Tue, 24 Nov 2009 01:07:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753517AbZKXGHd (ORCPT ); Tue, 24 Nov 2009 01:07:33 -0500 Received: from mga09.intel.com ([134.134.136.24]:24336 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750741AbZKXGHd (ORCPT ); Tue, 24 Nov 2009 01:07:33 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.47,276,1257148800"; d="scan'208";a="470030343" Message-ID: <4B0B782A.4030901@linux.intel.com> Date: Mon, 23 Nov 2009 22:07:38 -0800 From: Arjan van de Ven User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Peter Zijlstra CC: Peter P Waskiewicz Jr , Yong Zhang , "linux-kernel@vger.kernel.org" , "arjan@linux.jf.intel.com" , "davem@davemloft.net" , "netdev@vger.kernel.org" Subject: Re: [PATCH] irq: Add node_affinity CPU masks for smarter irqbalance hints 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> In-Reply-To: <1258995923.4531.715.camel@laptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1601 Lines: 32 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..... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/