Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Theodore Ts'o <tytso@xxxxxxx> Cc: Greg Thelen <gthelen@xxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Roman Gushchin <songmuchun@xxxxxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx> Cc: riel@xxxxxxxxxxx Cc: linux-mm@xxxxxxxxx Cc: linux-fsdevel@xxxxxxxxxxxxxxx Cc: cgroups@xxxxxxxxxxxxxxx --- Documentation/filesystems/tmpfs.rst | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst index 0408c245785e3..1ab04e8fa9222 100644 --- a/Documentation/filesystems/tmpfs.rst +++ b/Documentation/filesystems/tmpfs.rst @@ -137,6 +137,23 @@ mount options. It can be added later, when the tmpfs is already mounted on MountPoint, by 'mount -o remount,mpol=Policy:NodeList MountPoint'. +If CONFIG_MEMCG is enabled, tmpfs has a mount option to specify the memory +cgroup to be charged for page allocations. + +memcg=/sys/fs/cgroup/unified/test/: data page allocations are charged to +cgroup /sys/fs/cgroup/unified/test/. + +When charging memory to the remote memcg (memcg specified with memcg=) and +hitting the limit, the oom-killer will be invoked and will attempt to kill +a process in the remote memcg. If no such processes are found, the remote +charging process gets an ENOMEM. If the remote charging process is in the +pagefault path, it gets killed. + +Only processes that have access to /sys/fs/cgroup/unified/test/cgroup.procs can +mount a tmpfs with memcg=/sys/fs/cgroup/unified/test. Thus, a process is able +to charge memory to a cgroup only if it itself is able to enter that cgroup. + + To specify the initial root directory you can use the following mount options: -- 2.34.0.rc0.344.g81b53c2807-goog
