From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: Re: [PATCH 1 of 4 RFC] xen, p2m: get_entry returns level of entry as well Date: Thu, 14 Jun 2012 16:01:03 +0100 Message-ID: <4FD9FCAF.4050002@eu.citrix.com> References: <672e9628f27845d24a3f.1339156491@elijah> <20120614102116.GH82539@ocelot.phlegethon.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120614102116.GH82539@ocelot.phlegethon.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Tim Deegan Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 14/06/12 11:21, Tim Deegan wrote: > At 12:54 +0100 on 08 Jun (1339160091), George Dunlap wrote: >> Return the p2m level of the entry which filled this request. >> Intended to be used to see if pages returned by the balloon >> driver are part of a superpage, and reclaim them if so. > This looks broadly correct, but it's a bit invasive. If there's any way > to rework patch 2 not to need it that would be helpful. It looks like > the main use is for detecting and removing superpage PoD entries; maybe > that could be done with a sweep like you have in the non-PoD case? You mean the non-balloon case? I forget why I thought that was a bad idea, exactly. Let me think about that. > One niggle: returning level=5 on error is non-obvious, and it doesn't > look like your code in patch 2 uses that. Were you thinking -1 or something like that? -George