Re: [Xen-devel] [PATCH v2 03/30] xen/x86: fix parameters and return value of *_set_allocation functions

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 29.09.16 at 16:33, <roger.pau@xxxxxxxxxx> wrote:
> On Thu, Sep 29, 2016 at 04:39:02AM -0600, Jan Beulich wrote:
>> >>> On 27.09.16 at 17:56, <roger.pau@xxxxxxxxxx> wrote:
>> > Return should be an int, and the number of pages should be an unsigned 
>> > long.
>> 
>> I can see the former, but why the latter? Acting on 32-bit quantities
>> is a little cheaper after all.
> 
> This was requested by Andrew in the previous version:
> 
> https://lists.xenproject.org/archives/html/xen-devel/2016-07/msg03126.html 
> 
> But yes, an unsigned int is enough to hold the maximum number of pages for 
> a domain given than we support up to 1TB for HVM guests. Or maybe there are 
> plans to increase the maximum supported memory per guest?

Larger guests or not - here we're talking about number of pages
used internally for page tables, not numbers of pages assigned
to the guest, aren't we? In any event I'm not sure which truncation
issue Andrew had spotted back then.

Jan


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