Re: interaction of MADV_PAGEOUT with CoW anonymous mappings?

From: Michal Hocko
Date: Tue Mar 17 2020 - 11:59:01 EST


On Tue 17-03-20 08:00:55, Minchan Kim wrote:
> On Tue, Mar 17, 2020 at 08:12:39AM +0100, Michal Hocko wrote:
[...]
> > Just to make it clear, are you really suggesting to special case
> > page_check_references for madvise path?
> >
>
> No, (page_mapcount() > 1) checks *effectively* fixes the performance
> bug as well as vulnerability issue.

Ahh, ok then we are on the same page. You were replying to the part
where I have pointed out that you can control aging by these calls
and your response suggested that this is somehow undesirable behavior or
even a bug.

--
Michal Hocko
SUSE Labs