Re: [PATCH 04/40] xen: document Xen is using an unused bit for thepagetables

From: Andrea Arcangeli
Date: Tue Jul 03 2012 - 06:47:14 EST

Hi Konrad,

On Sat, Jun 30, 2012 at 12:47:18AM -0400, Konrad Rzeszutek Wilk wrote:
> On Thu, Jun 28, 2012 at 02:55:44PM +0200, Andrea Arcangeli wrote:
> > Xen has taken over the last reserved bit available for the pagetables
> Some time ago when I saw this patch I asked about it (if there is way
> to actually stop using this bit) and you mentioned it is not the last
> bit available for pagemaps. Perhaps you should alter the comment
> in this description?

As far as I can tell the comment is correct, it is the last bit
available. Simply I don't need to use it anymore. There are 3 reserved
bits, one is used by Xen, the second is used by SPECIAL the third is
used by kmemcheck.

> > which is set through ioremap, this documents it and makes the code
> It actually is through ioremap, gntdev (to map another guest memory),
> and on pfns which fall in E820 on the non-RAM and gap sections.

Well I dropped this patch, there's too much other important work to
do, this is only a documentation improvement and a cleanup and I don't
need it.
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