Re: [External] Re: [PATCH v2 03/19] mm/hugetlb: Introduce a new config HUGETLB_PAGE_FREE_VMEMMAP

[Muchun Song]

On Thu, Oct 29, 2020 at 6:29 PM Oscar Salvador <osalvador@xxxxxxx> wrote:
>
> On Mon, Oct 26, 2020 at 10:50:58PM +0800, Muchun Song wrote:
> > The purpose of introducing HUGETLB_PAGE_FREE_VMEMMAP is to configure
> > whether to enable the feature of freeing unused vmemmap associated
> > with HugeTLB pages. Now only support x86.
>
> Why this needs to be a config thing?
> If this space-memory-optimization does not come with a trade-off,
> why does the user have to set this instead of coming by default?

Now we only support x86_64. If we want to support other archs. We
need some arch special code to support this feature. In the future,
if this patch series is merged to mainline, I will implement this
optimization for other archs. At that time we can remove the
HUGETLB_PAGE_FREE_VMEMMAP.

Thanks.

>
>
> --
> Oscar Salvador
> SUSE L3



-- 
Yours,
Muchun