Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757085AbYBHXgq (ORCPT ); Fri, 8 Feb 2008 18:36:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751884AbYBHXgj (ORCPT ); Fri, 8 Feb 2008 18:36:39 -0500 Received: from relay2.sgi.com ([192.48.171.30]:33663 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751409AbYBHXgi (ORCPT ); Fri, 8 Feb 2008 18:36:38 -0500 Date: Fri, 8 Feb 2008 17:36:37 -0600 From: Robin Holt To: Christoph Lameter Cc: Andrew Morton , andrea@qumranet.com, holt@sgi.com, avi@qumranet.com, izike@qumranet.com, kvm-devel@lists.sourceforge.net, a.p.zijlstra@chello.nl, steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com, general@lists.openfabrics.org Subject: Re: [patch 0/6] MMU Notifiers V6 Message-ID: <20080208233636.GG26564@sgi.com> References: <20080208220616.089936205@sgi.com> <20080208142315.7fe4b95e.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1295 Lines: 28 On Fri, Feb 08, 2008 at 03:32:19PM -0800, Christoph Lameter wrote: > On Fri, 8 Feb 2008, Andrew Morton wrote: > > > What about ib_umem_get()? > > Ok. It pins using an elevated refcount. Same as XPmem right now. With that > we effectively pin a page (page migration will fail) but we will > continually be reclaiming the page and may repeatedly try to move it. We > have issues with XPmem causing too many pages to be pinned and thus the > OOM getting into weird behavior modes (OOM or stop lru scanning due to > all_reclaimable set). > > An elevated refcount will also not be noticed by any of the schemes under > consideration to improve LRU scanning performance. Christoph, I am not sure what you are saying here. With v4 and later, I thought we were able to use the rmap invalidation to remove the ref count that XPMEM was holding and therefore be able to swapout. Did I miss something? I agree the existing XPMEM does pin. I hope we are not saying the XPMEM based upon these patches will not be able to swap/migrate. Thanks, Robin -- 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/