On Mon 28-10-24 14:05:05, Joshua Hahn wrote: [...] > Changelog > v3: > * Removed check for whether CGRP_ROOT_HUGETLB_ACCOUNTING is on, since > this check is already handled by lruvec_stat_mod (and doing the > check in hugetlb.c actually breaks the build if MEMCG is not > enabled. [...] > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 190fa05635f4..fbb10e52d7ea 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1925,6 +1925,7 @@ void free_huge_folio(struct folio *folio) > pages_per_huge_page(h), folio); > hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h), > pages_per_huge_page(h), folio); > + lruvec_stat_mod_folio(folio, NR_HUGETLB, -pages_per_huge_page(h)); > mem_cgroup_uncharge(folio); > if (restore_reserve) > h->resv_huge_pages++; > @@ -3093,6 +3094,7 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, > > if (!memcg_charge_ret) > mem_cgroup_commit_charge(folio, memcg); > + lruvec_stat_mod_folio(folio, NR_HUGETLB, pages_per_huge_page(h)); > mem_cgroup_put(memcg); > > return folio; I do not see any specific checks for CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING in these paths. I guess you wanted to say that you rely on mem_cgroup_commit_charge setting memcg pointer which then __lruvec_stat_mod_folio relies on when updating stats. I suspect this all is done because you want a global counter to be updated as well, right? Changelog doesn't say anything about that though. Why is this needed when /proc/meminfo already describes the global hugetlb usage? -- Michal Hocko SUSE Labs
