Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755723AbZFVObl (ORCPT ); Mon, 22 Jun 2009 10:31:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751763AbZFVObd (ORCPT ); Mon, 22 Jun 2009 10:31:33 -0400 Received: from zrtps0kp.nortel.com ([47.140.192.56]:45559 "EHLO zrtps0kp.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751341AbZFVObd (ORCPT ); Mon, 22 Jun 2009 10:31:33 -0400 Message-ID: <4A3F95A6.5040503@nortel.com> Date: Mon, 22 Jun 2009 08:31:02 -0600 From: "Chris Friesen" User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Dan Magenheimer CC: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, npiggin@suse.de, chris.mason@oracle.com, kurt.hackel@oracle.com, dave.mccracken@oracle.com, Avi Kivity , jeremy@goop.org, Rik van Riel , alan@lxorguk.ukuu.org.uk, Rusty Russell , Martin Schwidefsky , akpm@osdl.org, Marcelo Tosatti , Balbir Singh , tmem-devel@oss.oracle.com, sunil.mushran@oracle.com, linux-mm@kvack.org, Himanshu Raj Subject: Re: [RFC] transcendent memory for Linux References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 22 Jun 2009 14:31:08.0394 (UTC) FILETIME=[15183CA0:01C9F346] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1263 Lines: 31 Dan Magenheimer wrote: > What if there was a class of memory that is of unknown > and dynamically variable size, is addressable only indirectly > by the kernel, can be configured either as persistent or > as "ephemeral" (meaning it will be around for awhile, but > might disappear without warning), and is still fast enough > to be synchronously accessible? > > We call this latter class "transcendent memory" While true that this memory is "exceeding usual limits", the more important criteria is that it may disappear. It might be clearer to just call it "ephemeral memory". There is going to be some overhead due to the extra copying, and at times there could be two copies of data in memory. It seems possible that certain apps right a the borderline could end up running slower because they can't fit in the regular+ephemeral memory due to the duplication, while the same amount of memory used normally could have been sufficient. I suspect trying to optimize management of this could be difficult. Chris -- 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/