From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e6.ny.us.ibm.com (8.12.11/8.12.11) with ESMTP id j1FIdLJn018532 for ; Tue, 15 Feb 2005 13:39:21 -0500 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay02.pok.ibm.com (8.12.10/NCO/VER6.6) with ESMTP id j1FIdKBk269602 for ; Tue, 15 Feb 2005 13:39:20 -0500 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11/8.12.11) with ESMTP id j1FIdK7i014713 for ; Tue, 15 Feb 2005 13:39:20 -0500 Subject: Re: [RFC 2.6.11-rc2-mm2 7/7] mm: manual page migration -- sys_page_migrate From: Dave Hansen In-Reply-To: <20050215105056.GC19658@lnx-holt.americas.sgi.com> 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> Content-Type: text/plain Date: Tue, 15 Feb 2005 10:39:12 -0800 Message-Id: <1108492753.6154.82.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Robin Holt Cc: Ray Bryant , Hirokazu Takahashi , Hugh DIckins , Andrew Morton , Marcello Tosatti , Ray Bryant , linux-mm , linux-kernel List-ID: 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org