Re: Pinning ZONE_MOVABLE pages

From: David Hildenbrand
Date: Tue Nov 24 2020 - 03:44:47 EST


On 24.11.20 09:43, Michal Hocko wrote:
> On Mon 23-11-20 11:31:59, Pavel Tatashin wrote:
> [...]
>> Also, we still need to take care of the fault scenario.
>
> Forgot to reply to this part. I believe you mean this to be fault at gup
> time, right? Then the easiest way forward would be to either add yet
> another scoped flag or (maybe) better to generalize memalloc_nocma_* to
> imply that the allocated memory is going to be unmovable so drop
> __GFP_MOVABLE and also forbid CMA. I have to admit that I do not
> remember why long term pin on CMA pages is ok to go to movable but I
> strongly suspect this is just shifting problem around.

Agreed.


--
Thanks,

David / dhildenb