Re: [Xen-devel] [PATCH v5 7/8] xen: arm: use superpages in p2m when pages are suitably aligned

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Thu, 2014-07-10 at 11:36 +0100, Julien Grall wrote:
> 
> On 09/07/14 18:11, Ian Campbell wrote:
> > On Wed, 2014-07-09 at 17:28 +0100, Julien Grall wrote:
> >>> +        /*
> >>> +         * could flush up to the next boundary, but would need to be
> >>> +         * careful about preemption, so just do one page now and loop.
> >>
> >> At the first glance I though this code didn't handle correctly superpage
> >> flush. It took me several minutes to understand that you rely
> >> P2M_ONE_PROGRESS{,_NOP} to do the job for you.
> >>
> >> Can you explain this trick in the commit message?
> >
> > That's what the existing comment which you've quoted is attempting to
> > explain. Is it not clear enough? Can you suggest an improvement?
> >
> > Would "up to the next superpage boundary ... do one 4K page now and
> > loop" suffice?
> 
> I think the most confusing word is "loop". I was waiting for see a 
> "real" loop below.
> 
> I would explain that the outer function taking care of the loop.

OK.

 * could flush up to the next superpage boundary, but would need to be
 * careful about preemption, so just do one 4K page now and return
 * P2M_ONE_PROGRESS so that the caller will continue to loop over the
 * rest of the range.
 
?

Ian. 
 

> 
> Regards,
> 



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