WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] using PageForeign for pte allocation vs. shortcutting __

To: Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] using PageForeign for pte allocation vs. shortcutting __pte_free_tlb()
From: Gerd Hoffmann <kraxel@xxxxxxx>
Date: Tue, 09 Jan 2007 12:11:42 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 09 Jan 2007 03:11:20 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <45A3836D.76E4.0078.0@xxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <45A37AC3.76E4.0078.0@xxxxxxxxxx> <45A373A9.70304@xxxxxxx> <45A3836D.76E4.0078.0@xxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 1.5.0.9 (X11/20060911)
Jan Beulich wrote:
>>>> Gerd Hoffmann <kraxel@xxxxxxx> 09.01.07 11:51 >>>
>> Jan Beulich wrote:
>>> In the course of trying to get CONFIG_HIGHPTE to work I stumbled across this
>>> inconsistency between i386 and x86-64 Linux: i386 uses SetPageForeign() in
>>> (one the non-highpte) case of pte_alloc_one(), and leaves intact native's
>>> definition of __pte_free_tlb(), whereas x86-64 doesn't use the former but
>>> shortcuts the latter to just invoke pte_free(). Obviously it would be nice 
>>> for
>>> these two to be consistent,
>> x86-64 has no HIGHMEM zone, thus CONFIG_HIGHPTE has no effect (I'm
>> surprised it exists in the first place ...).
> 
> Of course (and no, such a config option doesn't exist for x86-64), but what
> relation does this have to the question asked?

guess (not having looked at the code at all) i386 does that because it
needs disturgish high and non-high ptes, whereas x86-64 simply has no
need for that, so I don't see the point in trying to make them
consistent ...

cheers,
  Gerd

-- 
Gerd Hoffmann <kraxel@xxxxxxx>

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel