Re: [RFC PATCH] mm: thp: grab the lock before manipulation defer list

[Michal Hocko]

On Thu 09-01-20 10:03:19, Wei Yang wrote:
> On Wed, Jan 08, 2020 at 10:40:41AM +0100, Michal Hocko wrote:
[...]
> >Moreover, look at the code you are trying to fix. Sure extending the
> >locking seem straightforward but does it result in a correct code
> >though? See my question in the previous email. How do we know that the
> >page is actually enqued in a non-empty list?
> 
> I may not get your point for the last sentence.
> 
> The list_empty() doesn't check the queue is empty but check the list, here is
> the page, is not enqueued into any list. Is this your concern?

My bad. For some reason I have misread the code and thought this was
get_deferred_split_queue rather than page_deferred_list. Sorry about the
confusion.
-- 
Michal Hocko
SUSE Labs