memcg/hugetlb: remove memcg hugetlb try-commit-cancel protocol

This patch fully removes the mem_cgroup_{try, commit, cancel}_charge
functions, as well as their hugetlb variants.

Link: https://lkml.kernel.org/r/20241211203951.764733-4-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 387470bed399303f134f03957fda55eab57ccaa8..6e74b8254d9b22187f34f3f8335affc8869a4425 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -620,8 +620,6 @@ 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);
 
 /**
@@ -646,9 +644,6 @@ 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,
@@ -679,7 +674,6 @@ 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);
 
@@ -1154,23 +1148,12 @@ 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_charge_hugetlb(struct folio* folio, gfp_t gfp)
 {
         return 0;
@@ -1194,11 +1177,6 @@ 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 c903e260a83014200facf885e6c0226cca5a00ff..7ddbb2d12eb9218943a803eb455c510c5736128a 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2383,21 +2383,6 @@ done_restock:
        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);
@@ -2411,18 +2396,6 @@ 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)
@@ -4510,7 +4483,9 @@ 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;
 }
@@ -4527,40 +4502,6 @@ int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
        return ret;
 }
 
-/**
- * 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;
-}
-
 /**
  * mem_cgroup_charge_hugetlb - charge the memcg for a hugetlb folio
  * @folio: folio being charged