From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e33.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id l9PKL2p0028725 for ; Thu, 25 Oct 2007 16:21:02 -0400 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l9PKL2ae043958 for ; Thu, 25 Oct 2007 14:21:02 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l9PKL1Hi025066 for ; Thu, 25 Oct 2007 14:21:02 -0600 Subject: Re: RFC/POC Make Page Tables Relocatable From: Dave Hansen In-Reply-To: References: <1193330774.4039.136.camel@localhost> <1193335725.24087.19.camel@localhost> <1193340182.24087.54.camel@localhost> <1193342419.24087.71.camel@localhost> Content-Type: text/plain Date: Thu, 25 Oct 2007 13:20:59 -0700 Message-Id: <1193343659.24087.82.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Ross Biro Cc: linux-mm@kvack.org, Mel Gorman List-ID: On Thu, 2007-10-25 at 16:10 -0400, Ross Biro wrote: > On 10/25/07, Dave Hansen wrote: > > How would it get freed? > > The process exists or ummaps the range of memory. The relocation code > is likely called on a different cpu in the node and currently has no > way to pin the data in memory. Perhaps finding a way to pin the page > would help the other locking issues, so it might solve lots of > problems. Taking a simple reference count on the page will keep it from getting freed. It won't keep it from getting _unused_, but it will against getting actually freed back to the allocator. But, if you get to this point and you have a page and the only person with a reference to it is you, it _should_ be completely empty of pte entries. They were all cleared at zap_pte_range() time. You need other mechanisms in place, anyway, to keep ptes from being instantiated or shot down while you're doing the copy itself. -- Dave -- 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