Re: [RFC PATCH v2 5/5] mm: Split move_pages_to_lru into 3 separate passes

Alex Shi
2020-08-20T09:56:36Z

在 2020/8/19 下午10:42, Alexander Duyck 写道:
>> It's actually changed the meaning from current func. which I had seen a bug if no relock.
>> but after move to 5.9 kernel, I can not reprodce the bug any more. I am not sure if 5.9 fixed
>> the problem, and we don't need relock here.
> So I am not sure what you mean here about "changed the meaning from
> the current func". Which function are you referring to and what
> changed?
>
> From what I can tell the pages cannot change memcg because they were
> isolated and had the LRU flag stripped. They shouldn't be able to
> change destination LRU vector as a result. Assuming that, then they
> can all be processed under same LRU lock and we can avoid having to
> release it until we are forced to do so to call putback_lru_page or
> destroy the compound pages that were freed while we were shrinking the
> LRU lists.
>

I had sent a bug which base on 5.8 kernel.
https://lkml.org/lkml/2020/7/28/465

I am not sure it was fixed in new kernel. The original line was introduced by Hugh Dickins
I believe it would be great if you can get comments from him.

Thanks
Alex