Messages in this thread | | | Date | Wed, 1 Jun 2022 17:32:11 -0400 | Subject | Re: [PATCH v2 2/2] blk-cgroup: Optimize blkcg_rstat_flush() | From | Waiman Long <> |
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On 6/1/22 17:28, Tejun Heo wrote: > 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. > Thanks for the explanation. It makes sense to me.
Cheers, Longman
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