On Wed, Jan 2, 2019 at 12:07 PM Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> wrote: > > We don't do page cache reparent anymore when offlining memcg, so update > force empty related content accordingly. > > Cc: Michal Hocko <mhocko@xxxxxxxx> > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> > --- > Documentation/cgroup-v1/memory.txt | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt > index 3682e99..8e2cb1d 100644 > --- a/Documentation/cgroup-v1/memory.txt > +++ b/Documentation/cgroup-v1/memory.txt > @@ -70,7 +70,7 @@ Brief summary of control files. > memory.soft_limit_in_bytes # set/show soft limit of memory usage > memory.stat # show various statistics > memory.use_hierarchy # set/show hierarchical account enabled > - memory.force_empty # trigger forced move charge to parent > + memory.force_empty # trigger forced page reclaim > memory.pressure_level # set memory pressure notifications > memory.swappiness # set/show swappiness parameter of vmscan > (See sysctl's vm.swappiness) > @@ -459,8 +459,9 @@ About use_hierarchy, see Section 6. > the cgroup will be reclaimed and as many pages reclaimed as possible. > > The typical use case for this interface is before calling rmdir(). > - Because rmdir() moves all pages to parent, some out-of-use page caches can be > - moved to the parent. If you want to avoid that, force_empty will be useful. > + Though rmdir() offlines memcg, but the memcg may still stay there due to > + charged file caches. Some out-of-use page caches may keep charged until > + memory pressure happens. If you want to avoid that, force_empty will be useful. > > Also, note that when memory.kmem.limit_in_bytes is set the charges due to > kernel pages will still be seen. This is not considered a failure and the > -- > 1.8.3.1 >
