A question of grant table version

A question of grant table version

[hotmaim]

Hi

I have a question on grant table version.
In 2.6.31 pvops kernel, there is a gnttab_request_version to request using version 2.
But this cannot be found in 2.6.3236 pvops kernel, that is it uses version 1.

So, the fact is newer kernel use older grant table version, it doesn,t make sense to me.
Could someone comfirm it is on purpose?

Many thanks.

RE: A question of grant table version

[MaoXiaoyun]

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Also, it looks like some commit has been missed to apply to 2.6.32.36
 
grant-table.c history in 2.6.31 
http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=history;f=drivers/xen/grant-table.c;h=09bb7425cd46097b3d96feb342508069c610d78d;hb=bb1a15e55ec665a64c8a9c6bd699b1f16ac01ff4
 
below commit is not found in 2.6.32




2009-10-07
Steven Smith
Extend the grant tables implementation with an improved... 
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Add support for transitive grants.
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Add support for copy only (sub-page) grants.
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Introduce support for version 2 grant tables. Use... 
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Fix a long-standing memory leak in the grant tables... 
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Introduce a live_maps facility for tracking which domai... 
blob | commitdiff | diff to current
 Am I right?
 
> Subject: A question of grant table version
> From: tinnycloud@hotmail.com
> Date: Sat, 9 Apr 2011 09:28:06 +0800
> To: xen-devel@lists.xensource.com
> 
> Hi
> 
> I have a question on grant table version.
> In 2.6.31 pvops kernel, there is a gnttab_request_version to request using version 2.
> But this cannot be found in 2.6.3236 pvops kernel, that is it uses version 1.
> 
> So, the fact is newer kernel use older grant table version, it doesn,t make sense to me.
> Could someone comfirm it is on purpose?
> 
> Many thanks.
 		 	   		  

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RE: A question of grant table version

[MaoXiaoyun]

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Sorry, this is grant-table.c history in 2.6.31 
http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=history;f=drivers/xen/grant-table.c;h=6c6f8848537aa240ae09dbb87a30927e06a0a044;hb=641c127b67b3b1a4f6a79b6189ed2189cec46012
 


From: tinnycloud@hotmail.com
To: xen-devel@lists.xensource.com
CC: tinnycloud@hotmail.com
Subject: RE: A question of grant table version
Date: Sat, 9 Apr 2011 11:35:33 +0800




Also, it looks like some commit has been missed to apply to 2.6.32.36
 
grant-table.c history in 2.6.31 
http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=history;f=drivers/xen/grant-table.c;h=09bb7425cd46097b3d96feb342508069c610d78d;hb=bb1a15e55ec665a64c8a9c6bd699b1f16ac01ff4
 
below commit is not found in 2.6.32




2009-10-07
Steven Smith
Extend the grant tables implementation with an improved... 
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Add support for transitive grants.
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Add support for copy only (sub-page) grants.
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Introduce support for version 2 grant tables. Use... 
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Fix a long-standing memory leak in the grant tables... 
blob | commitdiff | diff to current

2009-10-07
Steven Smith
Introduce a live_maps facility for tracking which domai... 
blob | commitdiff | diff to current
 Am I right?
 
> Subject: A question of grant table version
> From: tinnycloud@hotmail.com
> Date: Sat, 9 Apr 2011 09:28:06 +0800
> To: xen-devel@lists.xensource.com
> 
> Hi
> 
> I have a question on grant table version.
> In 2.6.31 pvops kernel, there is a gnttab_request_version to request using version 2.
> But this cannot be found in 2.6.3236 pvops kernel, that is it uses version 1.
> 
> So, the fact is newer kernel use older grant table version, it doesn,t make sense to me.
> Could someone comfirm it is on purpose?
> 
> Many thanks.
 		 	   		  

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[-- Attachment #2: Type: text/plain, Size: 138 bytes --]

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http://lists.xensource.com/xen-devel

Re: A question of grant table version

[Ian Campbell]

On Sat, 2011-04-09 at 02:28 +0100, hotmaim wrote:
> Hi
> 
> I have a question on grant table version.
> In 2.6.31 pvops kernel, there is a gnttab_request_version to request using version 2.
> But this cannot be found in 2.6.3236 pvops kernel, that is it uses version 1.
> 
> So, the fact is newer kernel use older grant table version, it doesn,t make sense to me.
> Could someone comfirm it is on purpose?

Unless you specifically need the new functionality of grant table v2
(transitive grants or sub page grants) there is no difference/benefit
between v1 and v2.

The only user of that new functionality was netchannel2, which has not
been carried forward from 2.6.31 and hence current kernels still use v1
grant tables with no loss of functionality.

People are working on introducing the interesting features of
netchannel2 as protocol extensions to netchannel1 and it is likely that
this will also involve reintroducing the use of grant table v2 in newer
kernels.

Ian.