Re: [PATCH V2 0/5] Huge pages for short descriptors on ARM

Will Deacon
2014-04-24T10:37:28Z

Hi Steve,

On Thu, Apr 24, 2014 at 11:22:29AM +0100, Steve Capper wrote:
> On Wed, Apr 16, 2014 at 12:46:38PM +0100, Steve Capper wrote:
> Just a ping on this...
>
> I would really like to get huge page support for short descriptors on
> ARM merged as I've been carrying around these patches for a long time.
>
> Recently I've had no issues raised about the code. The patches have
> been tested and found to be both beneficial to system performance and
> stable.
>
> There are two parts to the series, the first patch is a core mm/ patch
> that introduces some huge_pte_ helper functions that allows for a much
> simpler ARM (without LPAE) implementation. The second part is the
> actual arch/arm code.
>
> I'm not sure how to proceed with these patches. I was thinking that
> they could be picked up into linux-next? If that sounds reasonable;
> Andrew, would you like to take the mm/ patch and Russell could you
> please take the arch/arm patches?
>
> Also, I was hoping to get these into 3.16. Are there any objections to
> that?

Who is asking for this code? We already support hugepages for LPAE systems,
so this would be targetting what? A9? I'm reluctant to add ~400 lines of
subtle, low-level mm code to arch/arm/ if it doesn't have any active users.

I guess I'm after some commitment that this is (a) useful to somebody and
(b) going to be tested regularly, otherwise it will go the way of things
like big-endian, where we end up carrying around code which is broken more
often than not (although big-endian is more self-contained).

Will