From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from psmtp.com (na3sys010amx142.postini.com [74.125.245.142])
	by kanga.kvack.org (Postfix) with SMTP id B99D56B0044
	for <linux-mm@kvack.org>; Fri, 16 Mar 2012 17:13:28 -0400 (EDT)
Message-ID: <1331932375.18960.237.camel@twins>
Subject: Re: [RFC][PATCH 10/26] mm, mpol: Make mempolicy home-node aware
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 16 Mar 2012 22:12:55 +0100
In-Reply-To: <alpine.DEB.2.00.1203161333370.10211@router.home>
References: <20120316144028.036474157@chello.nl>
	 <20120316144240.763518310@chello.nl>
	 <alpine.DEB.2.00.1203161333370.10211@router.home>
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: quoted-printable
Mime-Version: 1.0
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>, Paul Turner <pjt@google.com>, Suresh Siddha <suresh.b.siddha@intel.com>, Mike Galbraith <efault@gmx.de>, "Paul E.
 McKenney" <paulmck@linux.vnet.ibm.com>, Lai Jiangshan <laijs@cn.fujitsu.com>, Dan Smith <danms@us.ibm.com>, Bharata B Rao <bharata.rao@gmail.com>, Lee Schermerhorn <Lee.Schermerhorn@hp.com>, Andrea Arcangeli <aarcange@redhat.com>, Rik van Riel <riel@redhat.com>, Johannes Weiner <hannes@cmpxchg.org>, linux-kernel@vger.kernel.org, linux-mm@kvack.org

On Fri, 2012-03-16 at 13:34 -0500, Christoph Lameter wrote:
> On Fri, 16 Mar 2012, Peter Zijlstra wrote:
>=20
> > Add another layer of fallback policy to make the home node concept
> > useful from a memory allocation PoV.
> >
> > This changes the mpol order to:
> >
> >  - vma->vm_ops->get_policy	[if applicable]
> >  - vma->vm_policy		[if applicable]
> >  - task->mempolicy
> >  - tsk_home_node() preferred	[NEW]
> >  - default_policy
> >
> > Note that the tsk_home_node() policy has Migrate-on-Fault enabled to
> > facilitate efficient on-demand memory migration.
>=20
> The numa hierachy is already complex. Could we avoid adding another layer
> by adding a MPOL_HOME_NODE and make that the default?

Not sure that's really a win, the behaviour would be the same we just
have to implement another policy, which is likely more code.

--
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/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>