[Please do not top-post]

On Thu 10-08-17 16:10:45, wang Yu wrote:

at first ,thanks for your reply.
but i also tested what you said, the problem is also.
force_empty only call try_to_free_pages, not all the pages remove
because mem_cgroup_reparent_charges moved

Right. An alternative would be dropping the page cache globaly via
/proc/sys/vm/drop_caches. Not an ideal solution but it should help.
-- 
Michal Hocko
SUSE Labs