Re: mm: pages are not freed from lru_add_pvecs after process termination

[Michal Hocko]

On Thu 05-05-16 17:25:07, Odzioba, Lukasz wrote:
> On Thu 05-05-16 09:21:00, Michal Hocko wrote: 
> > OK, it wasn't that tricky afterall. Maybe I have missed something but
> > the following should work. Or maybe the async nature of flushing turns
> > out to be just impractical and unreliable and we will end up skipping
> > THP (or all compound pages) for pcp LRU add cache. Let's see...
> 
> Initially this issue was found on RH's 3.10.x kernel, but now I am using 
> 4.6-rc6.
> 
> In overall it does help and under heavy load it is slightly better than the
> second patch. Unfortunately I am still able to hit 10-20% oom kills with it -
> (went down from 30-50%) partially due to earlier vmstat_update call
>  - it went up to 25-25% with this patch below:

This simply shows that this is not a viable option. So I guess we really
want to rather skip THP (compound pages) from LRU add pcp cache. Thanks
for your effort and testing!
-- 
Michal Hocko
SUSE Labs