Re: [Xen-devel] More on 2.6.28 and balloon driver

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

Dan Magenheimer wrote:
> > It appears that in the upstream balloon driver,
> > the call to HYPERVISOR_update_va_mapping is missing
> > from decrease_reservation.  I think as a result,
> > the balloon driver is eating memory but not
> > releasing it to Xen, thus rendering the balloon
> > driver essentially useless.  (Can be observed via xentop.)
> >     
> Limited testing, but it appears that adding it
> back in with this simple patch to linux-2.6.28
> makes ballooning work properly.
>   
Thanks.  That's a pretty embarrassing oversight :/

> As the code is lifted from the original Xen balloon driver,
> I'm not sure I need this, but:
>
> Signed-off-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
>   
Yeah, the S-o-b line is a way to keep track of who a patch went via.  
It's "I assert that I'm allowed to post this patch".  In theory you'd 
include the previous S-o-b lines (if any), but a reference to the source 
repo/version would be enough in this case.
   J

> Dan
>
> P.S. Attachement is same, provided in case my mailer
> messes up this >80-char-width patch.
>
>
> --- linux-2.6.28/drivers/xen/balloon.c.orig     2009-01-07 12:35:48.000000000 
> -0700
> +++ linux-2.6.28/drivers/xen/balloon.c  2009-01-07 12:36:06.000000000 -0700
> @@ -296,6 +296,11 @@
>                 frame_list[i] = pfn_to_mfn(pfn);
>  
>  		scrub_page(page);
> +
> +               ret = HYPERVISOR_update_va_mapping(
> +                       (unsigned long)__va(pfn << PAGE_SHIFT),
> +                       __pte_ma(0), 0);
> +               BUG_ON(ret);
>         }
>  
>  	/* Ensure that ballooned highmem pages don't have kmaps. */
> ------------------------------------------------------------------------
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
>   

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