Re: [PATCH v3] mm/page_owner: fix for deferred struct page init

From: Michal Hocko
Date: Tue Jan 08 2019 - 17:40:44 EST


On Tue 08-01-19 17:13:41, Qian Cai wrote:
>
>
> On 1/8/19 5:02 PM, Andrew Morton wrote:
> >
> > It's unclear (to me) where we stand with this patch. Shold we proceed
> > with v3 for now, or is something else planned?
>
> I don't have anything else plan for this right now. Michal particular don't like
> that 4-line ifdef which supposes to avoid an immediately regression (arguably
> small) that existing page_owner users with DEFERRED_STRUCT_PAGE_INIT deselected
> that would start to miss tens of thousands early page allocation call sites. So,
> feel free to choose v2 of this which has no ifdef if you agree with Michal too.
> I am fine either way.

Yes I would prefer to revert the faulty commit (fe53ca54270) and work on
a more robust page_owner initialization to cover earlier allocations on
top of that.

Not that I would insist but this would be a more straightforward
approach and I hope it will result in a better long term maintainable
code in the end.

--
Michal Hocko
SUSE Labs