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

[Xen-devel] Re: [PATCH 01/10] xen: Make all reserved pages for the ballo

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: [Xen-devel] Re: [PATCH 01/10] xen: Make all reserved pages for the balloon be INVALID_P2M_ENTRY.
From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Date: Wed, 22 Dec 2010 09:53:27 -0500
Cc: Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, Jan Beulich <JBeulich@xxxxxxxxxx>, hpa@xxxxxxxxx
Delivery-date: Wed, 22 Dec 2010 06:54:16 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4D1127FC.8060102@xxxxxxxx>
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/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <1292967460-15709-1-git-send-email-konrad.wilk@xxxxxxxxxx> <1292967460-15709-2-git-send-email-konrad.wilk@xxxxxxxxxx> <4D1127FC.8060102@xxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.20 (2009-06-14)
On Tue, Dec 21, 2010 at 02:19:40PM -0800, Jeremy Fitzhardinge wrote:
> On 12/21/2010 01:37 PM, Konrad Rzeszutek Wilk wrote:
> > This patch prepares ourselves for the case where void entries in the P2M
> > tree structure do not necessarily imply that the pages are missing.
> > With this, we diligently set regions that will be used by the
> > balloon driver to be INVALID_P2M_ENTRY and under the ownership
> > of the balloon driver.
> >
> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> > ---
> >  arch/x86/xen/setup.c  |    8 ++++++++
> >  drivers/xen/balloon.c |    1 +
> >  2 files changed, 9 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> > index b5a7f92..d984d36 100644
> > --- a/arch/x86/xen/setup.c
> > +++ b/arch/x86/xen/setup.c
> > @@ -52,6 +52,8 @@ phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
> >  
> >  static __init void xen_add_extra_mem(unsigned long pages)
> >  {
> > +   unsigned long pfn;
> > +
> >     u64 size = (u64)pages * PAGE_SIZE;
> >     u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
> >  
> > @@ -66,6 +68,11 @@ static __init void xen_add_extra_mem(unsigned long pages)
> >     xen_extra_mem_size += size;
> >  
> >     xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
> > +
> > +   for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++) {
> > +           BUG_ON(!set_phys_to_machine(pfn, INVALID_P2M_ENTRY));
> 
> Use __set_phys_to_machine where you don't expect (or can't allow) any
> allocation.

Are you OK with me moving then this check:

    if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
                BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
                return true;
        }    
from set_phys_to_machine to __set_phys_to_machine?

> 
> Also, I'm not a fan of hiding real side-effectful code in a BUG_ON
> predicate.

Ok. Will expunge these.

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

<Prev in Thread] Current Thread [Next in Thread>