On Fri, Nov 08, 2024 at 01:29:44PM -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-off-by: Joshua Hahn <joshua.hahnjy@xxxxxxxxx>
>
> ---
> mm/memcontrol.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index f3a9653cef0e..97f63ec9c9fb 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1425,6 +1425,9 @@ unsigned long memcg_page_state_local_output(struct mem_cgroup *memcg, int item)
> memcg_page_state_output_unit(item);
> }
>
> +/* Forward declaration */
> +bool memcg_accounts_hugetlb(void);
No need for forward declaration. Just define it here and make it static.
> +
> static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
> {
> int i;
> @@ -1446,7 +1449,7 @@ static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
>
> #ifdef CONFIG_HUGETLB_PAGE
> if (unlikely(memory_stats[i].idx == NR_HUGETLB) &&
> - !(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING))
> + !memcg_accounts_hugetlb())
> continue;
> #endif
> size = memcg_page_state_output(memcg, memory_stats[i].idx);
> @@ -4483,6 +4486,15 @@ int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
> return ret;
> }
>
> +bool memcg_accounts_hugetlb(void)
> +{
> +#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.
> @@ -4508,8 +4520,7 @@ 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))
> + !cgroup_subsys_on_dfl(memory_cgrp_subsys) || !memcg_accounts_hugetlb())
> return -EOPNOTSUPP;
>
> if (try_charge(memcg, gfp, nr_pages))
> --
> 2.43.5
>
