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] gntdev: switch back to rwlocks

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: [Xen-devel] Re: [PATCH] gntdev: switch back to rwlocks
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Date: Fri, 9 Jul 2010 16:12:23 +0100
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>
Delivery-date: Fri, 09 Jul 2010 08:12:46 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4C373A75.9000800@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: <alpine.DEB.2.00.1007091527520.21432@kaball-desktop> <4C373A75.9000800@xxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Alpine 2.00 (DEB 1167 2008-08-23)
On Fri, 9 Jul 2010, Jeremy Fitzhardinge wrote:
> On 07/09/2010 07:32 AM, Stefano Stabellini wrote:
> > Hi Jeremy,
> > this patch switches back from spinlocks to rwlocks in gntdev, solving
> > the locking issue that was preventing stubdoms from working.
> > In particular the problem is that gntdev_mmap calls apply_to_page_range
> > after acquiring the spinlock. apply_to_page_range causes the mmu
> > notifiers to be called, so mn_invl_range_start will be called that will
> > try to acquire again the same spinlock.
> >   
> 
> I think the problem is that apply_to_page_range is calling the mmu
> notifiers at all.  It seems to be plain bogus; it should be up to the
> callers of apply_to_page_range to call the mmu notifiers if necessary.
> 
> Does removing those calls fix the problem?
> 

yep


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

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