Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932705AbVISVcV (ORCPT ); Mon, 19 Sep 2005 17:32:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932707AbVISVcV (ORCPT ); Mon, 19 Sep 2005 17:32:21 -0400 Received: from omx3-ext.sgi.com ([192.48.171.20]:46044 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S932705AbVISVcU (ORCPT ); Mon, 19 Sep 2005 17:32:20 -0400 Date: Mon, 19 Sep 2005 14:32:04 -0700 (PDT) From: Christoph Lameter To: Andi Kleen cc: Andrew Morton , torvalds@osdl.org, linux-kernel@vger.kernel.org Subject: Re: NUMA mempolicy /proc code in mainline shouldn't have been merged In-Reply-To: <20050919194038.GB12810@verdi.suse.de> Message-ID: References: <200509101120.19236.ak@suse.de> <20050910235139.4a8865c2.akpm@osdl.org> <200509110911.22212.ak@suse.de> <20050919194038.GB12810@verdi.suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1715 Lines: 34 On Mon, 19 Sep 2005, Andi Kleen wrote: > On Mon, Sep 19, 2005 at 10:11:20AM -0700, Christoph Lameter wrote: > > However, one still does not know which memory section (vma) is allocated > > on which nodes. And this may be important since critical data may need to > > Maybe. Well sure of things could be maybe important. Or maybe not. > Doesn't seem like a particularly strong case to add a lot of ugly > code though. We gradually need to fix the deficiencies of the policy layer. Calling fixes "ugly code" and refusing to discuss solutions does not help anyone. > > External memory policy management is a necessary feature for system > > administration, batch process scheduling as well as for testing and > > debugging a system. > > I'm not convinced of this at all. Most of these things proposed so far > can be done much simpler with 90% of the functionality (e.g. just swapoff > per process for migration) , and I haven't seen a clear rationale except > for lots of maybes that the missing 10% are worth all the complexity > you seem to plan to add. Have you ever had the challenge to work with large HPC applications on a large NUMA system? Which things? Many HPC apps do not use swap space at all and we likely wont be using swap for page migration (see Marcelo's work on a migration cache). All I have heard is you imagining complex solutions ("performance counters" etc) to things that would be simple if the policy layer would be up to the task. - 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/