On Wed, Nov 06, 2024 at 02:14:33PM -0800, Joshua Hahn wrote:
> This patch isolates the check for whether memcg accounts hugetlb.
> This condition can only be true if the memcg mount option
> memory_hugetlb_accounting is on, which includes hugetlb usage
> in memory.current.
>
> Signed-of-by: Joshua Hahn <joshua.hahnjy@xxxxxxxxx>
>
> ---
> include/linux/memcontrol.h | 2 ++
> mm/memcontrol.c | 12 ++++++++++--
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 34d2da05f2f1..25761d55799e 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -694,6 +694,8 @@ static inline int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm,
> return __mem_cgroup_charge(folio, mm, gfp);
> }
>
> +bool memcg_accounts_hugetlb(void);
> +
> int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
> long nr_pages);
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 5444d0e7bb64..59dea0122579 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4497,6 +4497,15 @@ int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
> return ret;
> }
>
> +bool memcg_accounts_hugetlb(void)
If this is only used in memcontrol.c then no need to add in the header,
just make it static here.
> +{
> +#ifdef CONFIG_HUGETLB_PAGE
> + return cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING;
> +#else
> + return false;
> +#endif
> +}
> +
> /**
> * mem_cgroup_hugetlb_try_charge - try to charge the memcg for a hugetlb folio
> * @memcg: memcg to charge.
> @@ -4522,8 +4531,7 @@ int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
> * but do not attempt to commit charge later (or cancel on error) either.
> */
> if (mem_cgroup_disabled() || !memcg ||
> - !cgroup_subsys_on_dfl(memory_cgrp_subsys) ||
> - !(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING))
Why not replace in mem_cgroup_hugetlb_try_charge() as well?
> + !cgroup_subsys_on_dfl(memory_cgrp_subsys) || !memcg_accounts_hugetlb())
> return -EOPNOTSUPP;
>
> if (try_charge(memcg, gfp, nr_pages))
> --
> 2.43.5
>
