On 7/19/18 3:40 AM, Bruce Merry wrote: > On 18 July 2018 at 17:49, Shakeel Butt <shakeelb@xxxxxxxxxx> wrote: >> On Wed, Jul 18, 2018 at 8:37 AM Bruce Merry <bmerry@xxxxxxxxx> wrote: >>> That sounds promising. Is there any way to tell how many zombies there >>> are, and is there any way to deliberately create zombies? If I can >>> produce zombies that might give me a reliable way to reproduce the >>> problem, which could then sensibly be tested against newer kernel >>> versions. >>> >> >> Yes, very easy to produce zombies, though I don't think kernel >> provides any way to tell how many zombies exist on the system. >> >> To create a zombie, first create a memcg node, enter that memcg, >> create a tmpfs file of few KiBs, exit the memcg and rmdir the memcg. >> That memcg will be a zombie until you delete that tmpfs file. > > Thanks, that makes sense. I'll see if I can reproduce the issue. Do > you expect the same thing to happen with normal (non-tmpfs) files that > are sitting in the page cache, and/or dentries? > Do you by any chance have use_hierarch=1? memcg_stat_show should just rely on counters inside the memory cgroup and the the LRU sizes for each node. Balbir Singh.
