From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx113.postini.com [74.125.245.113]) by kanga.kvack.org (Postfix) with SMTP id 9CAFD6B0062 for ; Fri, 29 Jun 2012 12:30:39 -0400 (EDT) Date: Fri, 29 Jun 2012 18:30:33 +0200 From: Petr Holasek Subject: Re: [PATCH v2] KSM: numa awareness sysfs knob Message-ID: <20120629163033.GA11327@stainedmachine.redhat.com> References: <1340970592-25001-1-git-send-email-pholasek@redhat.com> <20120629160510.GA10082@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120629160510.GA10082@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Hugh Dickins , Andrew Morton , Andrea Arcangeli , Chris Wright , Izik Eidus , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Anton Arapov On Fri, 29 Jun 2012, Johannes Weiner wrote: > On Fri, Jun 29, 2012 at 01:49:52PM +0200, Petr Holasek wrote: > > Introduces new sysfs boolean knob /sys/kernel/mm/ksm/merge_nodes > > which control merging pages across different numa nodes. > > When it is set to zero only pages from the same node are merged, > > otherwise pages from all nodes can be merged together (default behavior). > > Is it conceivable that admins may (in the future) want to merge only > across nodes that are below a given distance threshold? > > I'm not asking to implement this, just whether the knob can be > introduced such that it's future-compatible. Make it default to a > Very High Number and only allow setting it to 0 for now e.g.? And > name it max_node_merge_distance (I'm bad at names)? > > What do you think? I started with exactly same idea as you described above in the first RFC, link: https://lkml.org/lkml/2011/11/30/91 But this approach turned out to be more complicated than it looked (see two last emails in thread) and complexity of solution would rise a lot. Regards, Petr H -- 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: email@kvack.org