On Tue, May 05, 2015 at 12:45:43PM +0300, Vladimir Davydov wrote: > root->ino_ida is used for kernfs inode number allocations. Since IDA has > a layered structure, different IDs can reside on the same layer, which > is currently accounted to some memory cgroup. The problem is that each > kmem cache of a memory cgroup has its own directory on sysfs (under > /sys/fs/kernel/<cache-name>/cgroup). If the inode number of such a > directory or any file in it gets allocated from a layer accounted to the > cgroup which the cache is created for, the cgroup will get pinned for > good, because one has to free all kmem allocations accounted to a cgroup > in order to release it and destroy all its kmem caches. That said we > must not account layers of ino_ida to any memory cgroup. > > Since per net init operations may create new sysfs entries directly > (e.g. lo device) or indirectly (nf_conntrack creates a new kmem cache > per each namespace, which, in turn, creates new sysfs entries), an easy > way to reproduce this issue is by creating network namespace(s) from > inside a kmem-active memory cgroup. > > Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Man, that's nasty. For the kernfs part, Acked-by: Tejun Heo <tj@xxxxxxxxxx> Can you please repost this patch w/ Greg KH cc'd? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
