On Wed, Jun 01, 2022 at 05:25:53PM -0400, Waiman Long wrote: > I think the best way to protect against blkg destruction is to get a percpu > reference when put into lockless list and put it back when removed. > > BTW, when I ran a test that continuously create and destroy containers, the > total number of blkcg's kept on increasing. There are some freeing of > blkcg's but no freeing of blkg's at all. Maybe we have a similar dying > blkcg's problem here. I will take a further look at that when I have time. They get pinned by per-cgroup writebacks which gets pinned by lingering page cache and other remaining accounted memory areas, so I think they can hang around if there's no memory pressure. But, yeah, it'd be great to verify that they actually go away under memory pressure. Thanks. -- tejun
