On Tue 14-11-17 17:24:29, Roman Gushchin wrote: > This patch implements basic accounting of memory consumption > by hugetlbfs pages for cgroup v2 memory controller. > > Cgroup v2 memory controller lacks any visibility into the > hugetlbfs memory consumption. Cgroup v1 implemented a separate > hugetlbfs controller, which provided such stats, and also > provided some control abilities. Although porting of the > hugetlbfs controller to cgroup v2 is arguable a good idea and > is outside of scope of this patch, it's very useful to have > basic stats provided by memory.stat. Separate hugetlb cgroup controller was really a deliberate decision. We didn't want to mix hugetlb with the reclaimable memory. There is no reasonable way to enforce memcg limits if hugetlb pages are involved. AFAICS your patch shouldn't break the hugetlb controller because that one (ab)uses page[2].private to store the hstate for the accounting. You also do not really charge those hugetlb pages so the memcg accounting will work unchaged. So my primary question is, why don't you simply allow hugetlb controller rather than tweak stats for memcg? Is there any fundamental reason why hugetlb controller is not v2 compatible? It feels really strange to keeps stats of something the controller doesn't really control. I can imagine confused users claiming that numbers just do not add up... -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
