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Re: [Xen-devel] [PATCH 5/5] changes of common files for xen/ia64 dom0 vp

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 5/5] changes of common files for xen/ia64 dom0 vp model: netback work around
From: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Date: Sat, 29 Apr 2006 13:27:28 +0900
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
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On Fri, Apr 28, 2006 at 02:53:20PM +0100, Keir Fraser wrote:
> On 28 Apr 2006, at 03:56, Isaku Yamahata wrote:
> >Work around for vnif support of xen/ia64 with dom0 vp model.
> >This is a temporal work around until figuring out how to place a new 
> >page
> >after grant table page transfer.
> Does netback work *at all* for you with vp model? Looks like this patch 
> may make it build but not actually work, which makes it seem a bit 
> pointless.
> Anyway, two possible solutions are apparent to me:
>  1. netback gathers 'transmitted' skbuffs and then, in one batch, does 
> a populate_physmap() call to get new pages for all of them, the 
> kfree_skb()s each one back to system pool.
>  2. change semantics of grant transfers for vp guests so that the 
> operation automatically gets you a fresh page at the same 
> pseudo-physical address.
> Option (2) is maybe the better one? Then this patch would make more 
> sense (except that the code would be made run-time dependent on 
> autotranslate feature flag).

xen/ia64 with vp model adopted (2).
steal_page_for_grant_transfer() does it.
I attached the patch for netback.c. I tested only on xen/ia64 very roughly.
However I think steal_page_for_grant_transfer() in xen/arch/x86/mm.c
(or gnttab_transfer()) also needs modification. Right?


Attachment: 9889:4f7ee25edd81.patch
Description: Text document

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