On 6/19/19 11:35 AM, Shakeel Butt wrote: > On Wed, Jun 19, 2019 at 8:30 AM Waiman Long <longman@xxxxxxxxxx> wrote: >> On 6/19/19 11:18 AM, Shakeel Butt wrote: >>> On Wed, Jun 19, 2019 at 7:46 AM Waiman Long <longman@xxxxxxxxxx> wrote: >>>> There are concerns about memory leaks from extensive use of memory >>>> cgroups as each memory cgroup creates its own set of kmem caches. There >>>> is a possiblity that the memcg kmem caches may remain even after the >>>> memory cgroup removal. Therefore, it will be useful to show how many >>>> memcg caches are present for each of the kmem caches. >>>> >>>> This patch introduces a new <debugfs>/memcg_slabinfo file which is >>>> somewhat similar to /proc/slabinfo in format, but lists only slabs that >>>> are in memcg kmem caches. Information available in /proc/slabinfo are >>>> not repeated in memcg_slabinfo. >>>> >>> At Google, we have an interface /proc/slabinfo_full which shows each >>> kmem cache (root and memcg) on a separate line i.e. no accumulation. >>> This interface has helped us a lot for debugging zombies and memory >>> leaks. The name of the memcg kmem caches include the memcg name, css >>> id and "dead" for offlined memcgs. I think these extra information is >>> much more useful for debugging. What do you think? >>> >>> Shakeel >> Yes, I think that can be a good idea. My only concern is that it can be >> very verbose. Will work on a v2 patch. >> > Yes, it is very verbose but it is only for debugging and normal users > should not be (continuously) reading that interface. I am not against it. It is just an observation. I still think we can skip kmem caches that don't have any child memcg caches as the information is in slabinfo already. Cheers, Longman
