Re: [Xen-devel] xen pv hugepages

[Elena Ufimtseva <ufimtseva@xxxxxxxxx>]

On Thu, Feb 6, 2014 at 6:59 PM, Konrad Rzeszutek Wilk
<konrad.wilk@xxxxxxxxxx> wrote:
> On February 6, 2014 5:17:44 PM EST, Elena Ufimtseva <ufimtseva@xxxxxxxxx> 
> wrote:
>>Hello
>>
>>As I can see there is no support for hugepages in Xen for PV kernels.
>>Is this something in the future plans or there is no really need to
>>have this implemented?
>
> It was implemented. The UEK2 kernel (Oracle's) and SLES (I think) has this 
> implemented. But making it upstream means adding some Xen specific code in 
> the generic code which is a no-go.
>
> If you use PVH you get it for free. With the patches that Mukesh posted to 
> enable some cpuid flags I was able to boot a guest with 2MB and 1GB pages 
> without any trouble.

Ok, I see. Well, I would think then that the kernel then should not
provide any possibility to use it? Otherwise there are oopses and some
other unpleasant things happening when trying to use huge pages. I am
not sure, maybe if its clearly states that there is no hugetlb support
for pv, then there is no need for this?

>>
>>I came across this paper
>>https://www.kernel.org/doc/ols/2011/ols2011-gadre.pdf,
>>not sure if this was somehow presented to xen community, I can't find
>>any code related to this.
>>
>>Thank you!
>
>



-- 
Elena

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