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Re: [Xen-devel] [PATCH libxc] Remove set_max_grants in linux

To: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH libxc] Remove set_max_grants in linux
From: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
Date: Wed, 12 Jan 2011 12:57:46 -0500
Cc: jeremy@xxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, Ian.Campbell@xxxxxxxxxx, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
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On 01/12/2011 12:17 PM, Ian Jackson wrote:
> Daniel De Graaf writes ("[Xen-devel] [PATCH libxc] Remove set_max_grants in 
> linux"):
>> I just removed the linux version, because I didn't want to prevent its use
>> in minios where it is needed to resize the array of grants.
>> ------------------------------------------------------------------->8
>> The maximum number of grants is now constrained domain-wide in linux,
>> so set_max_grants should be a noop there. Previously, this constraint
>> was per-file-description.
> Is this unconditional change suitable for putting into xen-unstable.hg
> for the 4.1 release ?  In particular, will it break compatibility with
> "traditional Xen" kernels ?
> Ian.

It won't break compatibility; Linux has never required that you set the
limit in order to use grants. The default limit is set to the maximum
possible limit, so existing users cannot have been increasing it;
changing a possible decrease to a noop shouldn't break anything sane.

Daniel De Graaf
National Security Agency

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