Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261820AbVBOSyw (ORCPT ); Tue, 15 Feb 2005 13:54:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261823AbVBOSyw (ORCPT ); Tue, 15 Feb 2005 13:54:52 -0500 Received: from omx3-ext.sgi.com ([192.48.171.20]:41676 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S261820AbVBOSyt (ORCPT ); Tue, 15 Feb 2005 13:54:49 -0500 Message-ID: <42124551.8060401@sgi.com> Date: Tue, 15 Feb 2005 12:54:09 -0600 From: Ray Bryant User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040805 Netscape/7.2 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Dave Hansen CC: Robin Holt , Hirokazu Takahashi , Hugh DIckins , Andrew Morton , Marcello Tosatti , Ray Bryant , linux-mm , linux-kernel Subject: Re: [RFC 2.6.11-rc2-mm2 7/7] mm: manual page migration -- sys_page_migrate References: <20050212032535.18524.12046.26397@tomahawk.engr.sgi.com> <20050212032620.18524.15178.29731@tomahawk.engr.sgi.com> <1108242262.6154.39.camel@localhost> <20050214135221.GA20511@lnx-holt.americas.sgi.com> <1108407043.6154.49.camel@localhost> <20050214220148.GA11832@lnx-holt.americas.sgi.com> <1108419774.6154.58.camel@localhost> <20050215105056.GC19658@lnx-holt.americas.sgi.com> <1108492753.6154.82.camel@localhost> In-Reply-To: <1108492753.6154.82.camel@localhost> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2046 Lines: 45 Dave Hansen wrote: > On Tue, 2005-02-15 at 04:50 -0600, Robin Holt wrote: > >>What is the fundamental opposition to an array from from-to node mappings? >>They are not that difficult to follow. They make the expensive traversal >>of ptes the single pass operation. The time to scan the list of from nodes >>to locate the node this page belongs to is relatively quick when compared >>to the time to scan ptes and will result in probably no cache trashing >>like the long traversal of all ptes in the system required for multiple >>system calls. I can not see the node array as anything but the right way >>when compared to multiple system calls. What am I missing? > > > I don't really have any fundamental opposition. I'm just trying to make > sure that there's not a simpler (better) way of doing it. You've > obviously thought about it a lot more than I have, and I'm trying to > understand your process. > > As far as the execution speed with a simpler system call. Yes, it will > likely be slower. However, I'm not sure that the increase in scan time > is all that significant compared to the migration code (it's pretty > slow). > > -- Dave > > I'm worried about doing all of those find_get_page() things over and over when the mapped file we are migrating is large. I suppose one can argue that that is never going to be the case (e. g. no one in their right mind would migrate a job with a 300 GB mapped file). So we are back to the overlapping set of nodes issue. Let me look into this some more. -- ----------------------------------------------- Ray Bryant 512-453-9679 (work) 512-507-7807 (cell) raybry@sgi.com raybry@austin.rr.com The box said: "Requires Windows 98 or better", so I installed Linux. ----------------------------------------------- - 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/