On 11.04.2019 17:55, Waiman Long wrote: > On 04/11/2019 10:37 AM, Kirill Tkhai wrote: >> On 10.04.2019 22:13, Waiman Long wrote: >>> The current control mechanism for memory cgroup v2 lumps all the memory >>> together irrespective of the type of memory objects. However, there >>> are cases where users may have more concern about one type of memory >>> usage than the others. >>> >>> We have customer request to limit memory consumption on anonymous memory >>> only as they said the feature was available in other OSes like Solaris. >>> >>> To allow finer-grained control of memory, this patchset 2 new control >>> knobs for memory controller: >>> - memory.subset.list for specifying the type of memory to be under control. >>> - memory.subset.high for the high limit of memory consumption of that >>> memory type. >>> >>> For simplicity, the limit is not hierarchical and applies to only tasks >>> in the local memory cgroup. >>> >>> Waiman Long (2): >>> mm/memcontrol: Finer-grained control for subset of allocated memory >>> mm/memcontrol: Add a new MEMCG_SUBSET_HIGH event >>> >>> Documentation/admin-guide/cgroup-v2.rst | 35 +++++++++ >>> include/linux/memcontrol.h | 8 ++ >>> mm/memcontrol.c | 100 +++++++++++++++++++++++- >>> 3 files changed, 142 insertions(+), 1 deletion(-) >> CC Andrey. >> >> In Virtuozzo kernel we have similar functionality for limitation of page cache in a cgroup: >> >> https://github.com/OpenVZ/vzkernel/commit/8ceef5e0c07c7621fcb0e04ccc48a679dfeec4a4 > > It will be helpful to know the use case where you want to limit page > cache usage. I have anonymous memory in mind when I compose this patch, > but I make the mechanism more generic so that it can apply to other use > cases as well. We have distributed storage, and there are its daemons on every host. There are replication factor 1:N, so the same block may be duplicated on different hosts. They produce a lot of pagecache, but it is reused not often (because of the above 1:N). So, we want to limit pagecache, but do not limit anon memory. This prevents global reclaim, and we found this improves our performance tests. Kirill
