From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx123.postini.com [74.125.245.123]) by kanga.kvack.org (Postfix) with SMTP id F20A66B0062 for ; Fri, 29 Jun 2012 12:47:17 -0400 (EDT) Date: Fri, 29 Jun 2012 18:47:06 +0200 From: Johannes Weiner Subject: Re: [PATCH v2] KSM: numa awareness sysfs knob Message-ID: <20120629164706.GA7831@cmpxchg.org> References: <1340970592-25001-1-git-send-email-pholasek@redhat.com> <20120629160510.GA10082@cmpxchg.org> <20120629163033.GA11327@stainedmachine.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120629163033.GA11327@stainedmachine.redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Petr Holasek 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, Jun 29, 2012 at 06:30:33PM +0200, Petr Holasek wrote: > 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. Oh, I should have checked the archives given that it's v2. I expected it to get complex but didn't put enough thought into it to see /that/ amount of complexity. Sorry. Carry on, then :-) -- 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