On Fri, Nov 8, 2024 at 1:30 PM Joshua Hahn <joshua.hahnjy@xxxxxxxxx> wrote:
>
> This patch fully deprecates the mem_cgroup_{try, commit, cancel} charge
> functions, as well as their hugetlb variants. Please note that this
> patch relies on [1], which removes the last references (from memcg-v1)
> to some of these functions.
Nit: We are not really "deprecating" them, we are removing them.
Deprecation is usually tied to user-visible APIs that we cannot just
remove, at least not right away. Please rephrase the subject and
commit log accordingly.
>
> Signed-off-by: Joshua Hahn <joshua.hahnjy@xxxxxxxxx>
>
> [1] https://lore.kernel.org/linux-mm/20241025012304.2473312-1-shakeel.butt@xxxxxxxxx/
>
> ---
> include/linux/memcontrol.h | 22 -------------
> mm/memcontrol.c | 65 ++------------------------------------
> 2 files changed, 3 insertions(+), 84 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index d90c1ac791f1..75f15c4efe73 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -649,8 +649,6 @@ static inline bool mem_cgroup_below_min(struct mem_cgroup *target,
> page_counter_read(&memcg->memory);
> }
>
> -void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memcg);
> -
> int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp);
>
> /**
> @@ -675,9 +673,6 @@ static inline int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm,
> return __mem_cgroup_charge(folio, mm, gfp);
> }
>
> -int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
> - long nr_pages);
> -
> int mem_cgroup_charge_hugetlb(struct folio* folio, gfp_t gfp);
>
> int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm,
> @@ -708,7 +703,6 @@ static inline void mem_cgroup_uncharge_folios(struct folio_batch *folios)
> __mem_cgroup_uncharge_folios(folios);
> }
>
> -void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages);
> void mem_cgroup_replace_folio(struct folio *old, struct folio *new);
> void mem_cgroup_migrate(struct folio *old, struct folio *new);
>
> @@ -1167,23 +1161,12 @@ static inline bool mem_cgroup_below_min(struct mem_cgroup *target,
> return false;
> }
>
> -static inline void mem_cgroup_commit_charge(struct folio *folio,
> - struct mem_cgroup *memcg)
> -{
> -}
> -
> static inline int mem_cgroup_charge(struct folio *folio,
> struct mm_struct *mm, gfp_t gfp)
> {
> return 0;
> }
>
> -static inline int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg,
> - gfp_t gfp, long nr_pages)
> -{
> - return 0;
> -}
> -
> static inline int mem_cgroup_swapin_charge_folio(struct folio *folio,
> struct mm_struct *mm, gfp_t gfp, swp_entry_t entry)
> {
> @@ -1202,11 +1185,6 @@ static inline void mem_cgroup_uncharge_folios(struct folio_batch *folios)
> {
> }
>
> -static inline void mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
> - unsigned int nr_pages)
> -{
> -}
> -
> static inline void mem_cgroup_replace_folio(struct folio *old,
> struct folio *new)
> {
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 95ee77fe27af..17126d8d263d 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2351,21 +2351,6 @@ int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> return 0;
> }
>
> -/**
> - * mem_cgroup_cancel_charge() - cancel an uncommitted try_charge() call.
> - * @memcg: memcg previously charged.
> - * @nr_pages: number of pages previously charged.
> - */
> -void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
> -{
> - if (mem_cgroup_is_root(memcg))
> - return;
> -
> - page_counter_uncharge(&memcg->memory, nr_pages);
> - if (do_memsw_account())
> - page_counter_uncharge(&memcg->memsw, nr_pages);
> -}
> -
> static void commit_charge(struct folio *folio, struct mem_cgroup *memcg)
> {
> VM_BUG_ON_FOLIO(folio_memcg_charged(folio), folio);
> @@ -2379,18 +2364,6 @@ static void commit_charge(struct folio *folio, struct mem_cgroup *memcg)
> folio->memcg_data = (unsigned long)memcg;
> }
>
> -/**
> - * mem_cgroup_commit_charge - commit a previously successful try_charge().
> - * @folio: folio to commit the charge to.
> - * @memcg: memcg previously charged.
> - */
> -void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memcg)
> -{
> - css_get(&memcg->css);
> - commit_charge(folio, memcg);
> - memcg1_commit_charge(folio, memcg);
> -}
> -
> static inline void __mod_objcg_mlstate(struct obj_cgroup *objcg,
> struct pglist_data *pgdat,
> enum node_stat_item idx, int nr)
> @@ -4469,7 +4442,9 @@ static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg,
> if (ret)
> goto out;
>
> - mem_cgroup_commit_charge(folio, memcg);
> + css_get(&memcg->css);
> + commit_charge(folio, memcg);
> + memcg1_commit_charge(folio, memcg);
> out:
> return ret;
> }
> @@ -4495,40 +4470,6 @@ bool memcg_accounts_hugetlb(void)
> #endif
> }
>
> -/**
> - * mem_cgroup_hugetlb_try_charge - try to charge the memcg for a hugetlb folio
> - * @memcg: memcg to charge.
> - * @gfp: reclaim mode.
> - * @nr_pages: number of pages to charge.
> - *
> - * This function is called when allocating a huge page folio to determine if
> - * the memcg has the capacity for it. It does not commit the charge yet,
> - * as the hugetlb folio itself has not been obtained from the hugetlb pool.
> - *
> - * Once we have obtained the hugetlb folio, we can call
> - * mem_cgroup_commit_charge() to commit the charge. If we fail to obtain the
> - * folio, we should instead call mem_cgroup_cancel_charge() to undo the effect
> - * of try_charge().
> - *
> - * Returns 0 on success. Otherwise, an error code is returned.
> - */
> -int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
> - long nr_pages)
> -{
> - /*
> - * If hugetlb memcg charging is not enabled, do not fail hugetlb allocation,
> - * 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) || !memcg_accounts_hugetlb())
> - return -EOPNOTSUPP;
> -
> - if (try_charge(memcg, gfp, nr_pages))
> - return -ENOMEM;
> -
> - return 0;
> -}
> -
> int mem_cgroup_charge_hugetlb(struct folio *folio, gfp_t gfp)
> {
> struct mem_cgroup *memcg = get_mem_cgroup_from_current();
> --
> 2.43.5
>
>
