An associated css can be around for quite a while after a cgroup directory has been removed. In general, it makes sense to reset it to defaults so as not to worry about any remnants. For instance, memory cgroup needs to reset memory.low, otherwise pages charged to a dead cgroup might never get reclaimed. There's ->css_reset callback, which would fit perfectly for the purpose. Currently, it's only called when a subsystem is disabled in the unified hierarchy and there are other subsystems dependant on it. Let's call it on css destruction as well. Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx> Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> --- kernel/cgroup.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index cc40463e7b69..2ef78912c996 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5138,6 +5138,8 @@ static void kill_css(struct cgroup_subsys_state *css) * See seq_css() for details. */ css_clear_dir(css, NULL); + if (css->ss->css_reset) + css->ss->css_reset(css); /* * Killing would put the base ref, but we need to keep it alive -- 2.1.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>