On Mon, Sep 21, 2020 at 1:05 AM <zangchunxin@xxxxxxxxxxxxx> wrote: > > From: Chunxin Zang <zangchunxin@xxxxxxxxxxxxx> > > In the cgroup v1, we have 'force_mepty' interface. This is very > useful for userspace to actively release memory. But the cgroup > v2 does not. > > This patch reuse cgroup v1's function, but have a new name for > the interface. Because I think 'drop_cache' may be is easier to > understand :) > > Signed-off-by: Chunxin Zang <zangchunxin@xxxxxxxxxxxxx> > --- > Documentation/admin-guide/cgroup-v2.rst | 11 +++++++++++ > mm/memcontrol.c | 5 +++++ > 2 files changed, 16 insertions(+) > > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > index ce3e05e41724..fbff959c8116 100644 > --- a/Documentation/admin-guide/cgroup-v2.rst > +++ b/Documentation/admin-guide/cgroup-v2.rst > @@ -1181,6 +1181,17 @@ PAGE_SIZE multiple when read back. > high limit is used and monitored properly, this limit's > utility is limited to providing the final safety net. > > + memory.drop_cache > + A write-only single value file which exists on non-root > + cgroups. > + > + Provide a mechanism for users to actively trigger memory > + reclaim. The cgroup will be reclaimed and as many pages > + reclaimed as possible. > + > + It will broke low boundary. Because it tries to reclaim the > + memory many times, until the memory drops to a certain level. > + drop_cache is not really force_empty(). What is your use-case? Maybe you can use memory.reclaim [1] for your use-case. It is already in Andrew's tree. [1] https://lkml.kernel.org/r/20200909215752.1725525-1-shakeelb@xxxxxxxxxx
