Hi, On 2020/4/28 1:24, Roman Gushchin wrote: > On Mon, Apr 27, 2020 at 01:13:04PM -0400, Johannes Weiner wrote: >> +cc Roman who has been looking the most at this area >> >> On Mon, Apr 27, 2020 at 03:48:13PM +0800, Yang Yingliang wrote: >>> +cc linux-mm@kvack.org >>> >>> On 2020/4/26 19:21, Yang Yingliang wrote: >>>> Hi, >>>> >>>> When I doing the follow test in kernel-5.7-rc2, I found mem-free is >>>> decreased >>>> >>>> #!/bin/sh >>>> cd /sys/fs/cgroup/memory/ >>>> >>>> for((i=0;i<45;i++)) >>>> do >>>>         for((j=0;j<60000;j++)) >>>>         do >>>>                 mkdir /sys/fs/cgroup/memory/yyl-cg$j >>>>         done >>>>         sleep 1 >>>>         ls /sys/fs/cgroup/memory/ | grep yyl | xargs rmdir >>>> done >> Should be easy enough to reproduce, thanks for the report. I'll try to >> take a look later this week, unless Roman beats me to it. >> >> Is this a new observation in 5.7-rc2? >> >> Can you provide /sys/fs/cgroup/unified/cgroup.stat after the test? I re-tested in 5.7-rc3, it has same problem and the /sys/fs/cgroup/unified/cgroup.stat afther test is: nr_descendants 50 nr_dying_descendants 0 > I'm actually trying to reproduce it now, but so far haven't found any issues. > > Yang, can you, please, attach the config you're using? > > And also confirm that you're giving the system some time before looking > at the memory statistics? Reclaim of internal cgroup structure is a complex > process which might take some time to finish. > > Is dmesg also clean? config and dmesg are attached. > > Thanks!