From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
To: David Vrabel <david.vrabel@citrix.com>
Cc: xen-devel@lists.xensource.com,
Ian Campbell <Ian.Campbell@citrix.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
alex@alex.org.uk, dcrisan@flexiant.com
Subject: Re: [PATCH 0/3] make ballooned out pages have a valid mapping at all times
Date: Mon, 22 Jul 2013 16:35:30 +0100 [thread overview]
Message-ID: <alpine.DEB.2.02.1307221635150.4893@kaball.uk.xensource.com> (raw)
In-Reply-To: <51ED1A36.10200@citrix.com>
On Mon, 22 Jul 2013, David Vrabel wrote:
> On 21/07/13 18:32, Stefano Stabellini wrote:
> > Hi all,
> > this patch series limits problems caused by tcp retransmits on NFS when
> > the original block pages were mapped from a foreign domain and now the
> > mapping is gone.
> >
> > It accomplishes the goal by:
> >
> > 1) mapping all ballooned out pages to a "balloon_trade_page";
> > 2) making sure that once a grant is unmapped, the original mapping to
> > balloon_trade_page is restored atomically.
>
> I think this can be fixed without any hypervisor-side changes, although
> hypervisor changes will allow you to do it more efficiently.
>
> Use a per-CPU set of trade pages.
>
> Note MFN of this CPU's trade page (trade_mfn).
> Do the grant_unmap_and_replace(), (trade page mapping's MFN is cleared
> but this is ok as nothing is accessing the page via this mapping).
> update_va_mapping on trade page VA to set its MFN to trade_mfn.
I am going to go for this, avoiding any Xen side changes.
next prev parent reply other threads:[~2013-07-22 15:35 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-21 17:32 [PATCH 0/3] make ballooned out pages have a valid mapping at all times Stefano Stabellini
2013-07-21 17:32 ` [PATCH 1/3] xen/balloon: set a mapping for ballooned out pages Stefano Stabellini
2013-07-21 17:32 ` [PATCH 2/3] xen/grant_table: use the new GNTTABOP_unmap_and_replace hypercall Stefano Stabellini
2013-07-21 17:44 ` Ian Campbell
2013-07-22 10:38 ` Stefano Stabellini
2013-07-22 15:50 ` Ian Campbell
2013-07-23 14:08 ` Konrad Rzeszutek Wilk
2013-07-23 16:53 ` Stefano Stabellini
2013-07-21 17:32 ` [PATCH 3/3] xen/m2p: use GNTTABOP_unmap_and_replace to replace foreign grants with balloon_trade_page Stefano Stabellini
2013-07-21 17:49 ` Ian Campbell
2013-07-22 10:32 ` Stefano Stabellini
2013-07-22 11:40 ` [PATCH 0/3] make ballooned out pages have a valid mapping at all times David Vrabel
2013-07-22 15:35 ` Stefano Stabellini [this message]
2013-07-22 15:51 ` Ian Campbell
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