From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4212C481.9040103@sgi.com> Date: Tue, 15 Feb 2005 21:56:49 -0600 From: Ray Bryant MIME-Version: 1.0 Subject: Re: manual page migration -- issue list References: <42128B25.9030206@sgi.com> <20050215174109.238b7135.pj@sgi.com> In-Reply-To: <20050215174109.238b7135.pj@sgi.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Jackson Cc: linux-mm@kvack.org, holt@sgi.com, ak@muc.de, haveblue@us.ibm.com, marcello@cyclades.com, stevel@mwwireless.net, peterc@gelato.unsw.edu.au List-ID: Paul Jackson wrote: > A couple comments in response to Andi's earlier post on the > related lkml thread ... > > Andi wrote: > >>Sorry, but the only real difference between your API and mbind is that >>yours has a pid argument. > > > One other difference shouts out at me. I am unsure of my reading of > Andi's post, so I can't tell if (1) it was so obvious Andi didn't > bother mentioning it, or (2) he doesn't see it as a difference. > > That difference is this. > > The various numa mechanisms, such as mbind, set_mempolicy and cpusets, > as well as the simple first touch that MPI jobs rely on, are all about > setting a policy for where future allocations should go. > > This page migration mechanism is all about changing the placement of > physical pages of ram that are currently allocated. > > At any point in time, numa policy guides future allocations, and page > migration redoes past allocations. > Very nicely said, thanks. And the concern I have been trying to raise with Andi is: How does that page migration mechanism redo a past allocation using a memory policy if the orginal allocation was not done with a memory policy, but instead done via first touch? > > Andi wrote: > >>My thinking is the simplest way to handle that is to have a call that just >>migrates everything. > > > I might have ended up at the same place, not sure, when I just suggested > in my previous post: > > pj wrote: > >>As a straw man, let me push the factored migration call to the >>extreme, and propose a call: >> >> sys_page_migrate(pid, oldnode, newnode) >> >>that moves any physical page in the address space of pid that is >>currently located on oldnode to newnode. > > > -- ----------------------------------------------- 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, 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