Re: [PATCH 1/2] mm: fix bogus VM_BUG_ON_PAGE() in isolate_lru_page()

[Michal Hocko]

On Mon 01-02-16 16:26:08, Kirill A. Shutemov wrote:
> We don't care if there's a tail pages which is not on LRU. We are not
> going to isolate them anyway.

yes we are not going to isolate them but calling this function on a
tail page is wrong in principle, no? PageLRU check is racy outside of
lru_lock so what if we are racing here. I know, highly unlikely but not
impossible. So I am not really sure this is an improvement. When would
we hit this VM_BUG_ON and it wouldn't be a bug or at least suspicious
usage?
-- 
Michal Hocko
SUSE Labs