On Wed 03-04-13 10:53:54, Michal Hocko wrote: > mem_cgroup_css_online calls mem_cgroup_put if memcg_init_kmem > fails. This is not correct because only memcg_propagate_kmem takes an > additional reference while mem_cgroup_sockets_init is allowed to fail as > well (although no current implementation fails) but it doesn't take any > reference. This all suggests that it should be memcg_propagate_kmem that > should clean up after itself so this patch moves mem_cgroup_put over > there. > Unfortunately this is not that easy (as pointed out by Li Zefan) because > memcg_kmem_mark_dead marks the group dead (KMEM_ACCOUNTED_DEAD) if it > is marked active (KMEM_ACCOUNTED_ACTIVE) which is the case even if > memcg_propagate_kmem fails so the additional reference is dropped in > that case in kmem_cgroup_destroy which means that the reference would be > dropped two times. > > The easiest way then would be to simply remove mem_cgrroup_put from > mem_cgroup_css_online and rely on kmem_cgroup_destroy doing the right > thing. Forgot to mention that this one could be marked for stable for 3.8 > Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx> > Signed-off-by: Michal Hocko <mhocko@xxxxxxx> > --- > mm/memcontrol.c | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 6de6d70..65b2850 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -6417,14 +6417,6 @@ mem_cgroup_css_online(struct cgroup *cont) > > error = memcg_init_kmem(memcg, &mem_cgroup_subsys); > mutex_unlock(&memcg_create_mutex); > - if (error) { > - /* > - * We call put now because our (and parent's) refcnts > - * are already in place. mem_cgroup_put() will internally > - * call __mem_cgroup_free, so return directly > - */ > - mem_cgroup_put(memcg); > - } > return error; > } > > -- > 1.7.10.4 > > -- > 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> -- Michal Hocko SUSE Labs -- 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>