From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 30 Nov 2006 09:31:05 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC][PATCH 0/1] Node-based reclaim/migration Message-Id: <20061130093105.d872c49d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20061129030655.941148000@menage.corp.google.com> References: <20061129030655.941148000@menage.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: menage@google.com Cc: linux-mm@kvack.org, akpm@osdl.org List-ID: On Tue, 28 Nov 2006 19:06:55 -0800 menage@google.com wrote: > -- > > We're trying to use NUMA node isolation as a form of job resource > control at Google, and the existing page migration APIs are all bound > to individual processes and so are a bit clunky to use when you just > want to affect all the pages on a given node. > > How about an API to allow userspace to direct page migration (and page > reclaim) on a per-node basis? This patch provides such an API, based > around sysfs; a system call approach would certainly be possible too. > > It sort of overlaps with memory hot-unplug, but is simpler since it's > not so bad if we miss a few pages. > > Comments? Also, can anyone clarify whether I need any locking when > sacnning the pages in a pgdat? As far as I can see, even with memory > hotplug this number can only increase, not decrease. > Hi, I'm one of memory-hot-unplug men. (But I can't go ahead for now.) a few comments. 1. memory hot unplug will be implemnted based on *section* not on *node*. section <-> node relationship will be displayed. 2. AFAIK, migrating pages without taking write lock of any mm->sem will cause problem. anon_vma can be freed while migration. 3. It's maybe better to add a hook to stop page allocation from the target node(zone). you may want to use this feature under heavly load. Thanks, -Kame -- 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