On Thu 17-10-19 17:28:04, Roman Gushchin wrote: > This patchset provides a new implementation of the slab memory controller, > which aims to reach a much better slab utilization by sharing slab pages > between multiple memory cgroups. Below is the short description of the new > design (more details in commit messages). > > Accounting is performed per-object instead of per-page. Slab-related > vmstat counters are converted to bytes. Charging is performed on page-basis, > with rounding up and remembering leftovers. > > Memcg ownership data is stored in a per-slab-page vector: for each slab page > a vector of corresponding size is allocated. To keep slab memory reparenting > working, instead of saving a pointer to the memory cgroup directly an > intermediate object is used. It's simply a pointer to a memcg (which can be > easily changed to the parent) with a built-in reference counter. This scheme > allows to reparent all allocated objects without walking them over and changing > memcg pointer to the parent. > > Instead of creating an individual set of kmem_caches for each memory cgroup, > two global sets are used: the root set for non-accounted and root-cgroup > allocations and the second set for all other allocations. This allows to > simplify the lifetime management of individual kmem_caches: they are destroyed > with root counterparts. It allows to remove a good amount of code and make > things generally simpler. What is the performance impact? Also what is the effect on the memory reclaim side and the isolation. I would expect that mixing objects from different cgroups would have a negative/unpredictable impact on the memcg slab shrinking. -- Michal Hocko SUSE Labs
