Re: [PATCH v3 0/8] extend hugepage migration

From: Andi Kleen
Date: Fri Jul 19 2013 - 11:33:40 EST


On Thu, Jul 18, 2013 at 05:34:24PM -0400, Naoya Horiguchi wrote:
> Here is the 3rd version of hugepage migration patchset.
> I rebased it onto v3.11-rc1 and applied most of your feedbacks.
>
> Some works referred to in previous discussion (shown below) are not included
> in this patchset, but likely to be done after this work.
> - using page walker in check_range
> - split page table lock for pmd/pud based hugepage (maybe applicable to thp)

I did a quick read through the patchkit and it looks all good to me.
It also closes a long standing gap. Thanks!

Acked-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

> Hugepage migration of 1GB hugepage is not enabled for now, because
> I'm not sure whether users of 1GB hugepage really want it.
> We need to spare free hugepage in order to do migration, but I don't
> think that users want to 1GB memory to idle for that purpose
> (currently we can't expand/shrink 1GB hugepage pool after boot).

I think we'll need 1GB migration sooner or later. As memory sizes
go up 1GB use will be more common, and the limitation of not
expanding/shrinking 1GB will be eventually fixed.

It would be just a straight forward extension of your patchkit,
right?

-Andi
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