On Sat 19-01-19 22:30:16, Xiongchun Duan wrote: > we find that in huge memory system frequent creat creation and deletion > memcgroup make the system leave lots of offline memcgroup.we had seen 100000 > unrelease offline memcgroup in our system(512G memory). > > this memcgroup hold because some memory page still charged. > so we try to Multiple interval call force_empty to reclaim this memory page. > > after applying those patchs,in our system,the unrelease offline memcgroup > was reduced from 100000 to 100. I've stopped at patch 3 because all these patches really ask for much more justification. Please note that each patch should explain the problem, the proposed solution on highlevel and explain why it is done so. The cover letter should also explain the underlying problem. What does prevent those memcgs to be reclaim completely on force_empty? Besides that, I do agree that the current implementation of force_empty is rather suboptimal. There is a hardcoded retry loop counter which doesn't really make much sense to me. The context is interruptible and there is no real reason to have a retry count limit. If a userspace want to implement a policy it can do it from userspace - e.g. timeout 2m echo 0 > force_empty Last but not least a force_empty on offline has been proposed recently http://lkml.kernel.org/r/1547061285-100329-1-git-send-email-yang.shi@xxxxxxxxxxxxxxxxx I haven't followed up on that discussion yet but it is always better to check what where arguments there and explain why this approach is any better/different. > Xiongchun Duan (5): > Memcgroup: force empty after memcgroup offline > Memcgroup: Add timer to trigger workqueue > Memcgroup:add a global work > Memcgroup:Implement force empty work function > Memcgroup:add cgroup fs to show offline memcgroup status > > Documentation/cgroup-v1/memory.txt | 7 +- > Documentation/sysctl/kernel.txt | 10 ++ > include/linux/memcontrol.h | 11 ++ > kernel/sysctl.c | 9 ++ > mm/memcontrol.c | 271 +++++++++++++++++++++++++++++++++++++ > 5 files changed, 306 insertions(+), 2 deletions(-) > > -- > 1.8.3.1 -- Michal Hocko SUSE Labs
