Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751117AbVKATDD (ORCPT ); Tue, 1 Nov 2005 14:03:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751119AbVKATDC (ORCPT ); Tue, 1 Nov 2005 14:03:02 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:6536 "EHLO mx3.mail.elte.hu") by vger.kernel.org with ESMTP id S1751118AbVKATDA (ORCPT ); Tue, 1 Nov 2005 14:03:00 -0500 Date: Tue, 1 Nov 2005 20:02:49 +0100 From: Ingo Molnar To: Rob Landley Cc: Mel Gorman , Nick Piggin , "Martin J. Bligh" , Andrew Morton , kravetz@us.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, lhms-devel@lists.sourceforge.net Subject: Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19 Message-ID: <20051101190249.GA16738@elte.hu> References: <20051030235440.6938a0e9.akpm@osdl.org> <20051101144622.GC9911@elte.hu> <200511011233.36713.rob@landley.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200511011233.36713.rob@landley.net> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=AWL autolearn=disabled SpamAssassin version=3.0.3 0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1229 Lines: 26 * Rob Landley wrote: > On Tuesday 01 November 2005 08:46, Ingo Molnar wrote: > > how will the 100% solution handle a simple kmalloc()-ed kernel buffer, > > that is pinned down, and to/from which live pointers may exist? That > > alone can prevent RAM from being removable. > > Would you like to apply your "100% or nothing" argument to the virtual > memory management subsystem and see how it sounds in that context? > (As an argument that we shouldn't _have_ one?) that would be comparing apples to oranges. There is a big difference between "VM failures under high load", and "failure of VM functionality for no user-visible reason". The fragmentation problem here has nothing to do with pathological workloads. It has to do with 'unlucky' allocation patterns that pin down RAM areas which thus become non-removable. The RAM module will be non-removable for no user-visible reason. Possible under zero load, and with lots of free RAM otherwise. Ingo - 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/