Re: [RFC v1 00/19] Modify zonelist to nodelist v1

Qian Cai
2019-11-26T19:04:11Z

> On Nov 26, 2019, at 10:41 AM, Michal Hocko <mhocko@kernel.org> wrote:
>
> On Tue 26-11-19 10:30:56, Qian Cai wrote:
>>
>>
>>> On Nov 25, 2019, at 3:39 AM, Michal Hocko <mhocko@kernel.org> wrote:
>>>
>>> People do care about ZONE_MOVABLE and if there is a non-movable memory
>>> sitting there then it is a bug. Please report that.
>>
>> It is trivial to test yourself if you ever care. Just pass kernelcore=
>> to as many NUMA machines you could find, an then test if ever possible
>> to offline those memory.
>
> I definitely do care if you can provide more details (ideally in a
> separate email thread). I am using movable memory for memory hotplug
> usecases and so far I do not remember any kernel/non-movable allocations
> would make it in - modulo bugs when somebody might use __GFP_MOVABLE
> when it is not appropriate.
>

I don’t think it is anything to do with __GFP_MOVABLE. It is about booting a kernel
with either passing kernelcore= or movablecore=. Then, those ZONE_MOVABLE will
have non-movable pages which looks like those from vmemmap_populate(). How
do you create ZONE_MOVALBLE in this first place?