From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay05.boulder.ibm.com (d03relay05.boulder.ibm.com [9.17.195.107]) by e34.co.us.ibm.com (8.12.10/8.12.9) with ESMTP id j1EIp2MN112826 for ; Mon, 14 Feb 2005 13:51:02 -0500 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay05.boulder.ibm.com (8.12.10/NCO/VER6.6) with ESMTP id j1EIp1oO266136 for ; Mon, 14 Feb 2005 11:51:02 -0700 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.12.11/8.12.11) with ESMTP id j1EIp17b026635 for ; Mon, 14 Feb 2005 11:51:01 -0700 Subject: Re: [RFC 2.6.11-rc2-mm2 7/7] mm: manual page migration -- sys_page_migrate From: Dave Hansen In-Reply-To: <20050214135221.GA20511@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> Content-Type: text/plain Date: Mon, 14 Feb 2005 10:50:42 -0800 Message-Id: <1108407043.6154.49.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 Mon, 2005-02-14 at 07:52 -0600, Robin Holt wrote: > The node mask is a list of allowed. This is intended to be as near > to a one-to-one migration path as possible. If that's the case, it would make the kernel internals a bit simpler to only take a "from" and "to" node, instead of those maps. You'll end up making multiple syscalls, but that shouldn't be a problem. > > There also probably needs to be a bit more coordination between the > > other NUMA API and this one. I noticed that, for now, the migration > > loop only makes a limited number of passes. It appears that either you > > don't require that, once the syscall returns, that *all* pages have been > > migrated (there could have been allocations done behind the loop) or you > > have some way of keeping the process from doing any more allocations. > > It is intended that the process would be stopped during the migration > to simplify considerations such as overlapping destination node lists. Requiring that the process is stopped will somewhat limit the use of this API outside of the HPC space where so much control can be had over the processes. I have the feeling that very few other kinds of applications will be willing to be stopped for the time that it takes for a set of migrations to occur. But, if stopping the process is going to be a requirement, having more syscalls that take less time each should be desirable. -- 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