[RFC PATCH v1 6/7] mm: memcontrol: Remove now-unused function mem_cgroup_charge_hugetlb

[Ackerley Tng]

With the (re)introduction of the try-commit-cancel charging protocol for
HugeTLB's use, mem_cgroup_charge_hugetlb() is now redundant.

Remove the function's implementation from mm/memcontrol.c and its
declaration from include/linux/memcontrol.h

No functional change intended.

Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
 include/linux/memcontrol.h |  7 -------
 mm/memcontrol.c            | 34 ----------------------------------
 2 files changed, 41 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 59eab4caa01fa..572ad695afa40 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -668,8 +668,6 @@ static inline int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm,
 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,
 				  gfp_t gfp, swp_entry_t entry);
 
@@ -1158,11 +1156,6 @@ static inline int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg,
 	return 0;
 }
 
-static inline int mem_cgroup_charge_hugetlb(struct folio* folio, gfp_t gfp)
-{
-        return 0;
-}
-
 static inline int mem_cgroup_swapin_charge_folio(struct folio *folio,
 			struct mm_struct *mm, gfp_t gfp, swp_entry_t entry)
 {
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 70d762ba465b1..87d22db5a4bd3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4855,40 +4855,6 @@ int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
 	return 0;
 }
 
-/**
- * mem_cgroup_charge_hugetlb - charge the memcg for a hugetlb folio
- * @folio: folio being charged
- * @gfp: reclaim mode
- *
- * This function is called when allocating a huge page folio, after the page has
- * already been obtained and charged to the appropriate hugetlb cgroup
- * controller (if it is enabled).
- *
- * Returns ENOMEM if the memcg is already full.
- * Returns 0 if either the charge was successful, or if we skip the charging.
- */
-int mem_cgroup_charge_hugetlb(struct folio *folio, gfp_t gfp)
-{
-	struct mem_cgroup *memcg = get_mem_cgroup_from_current();
-	int ret = 0;
-
-	/*
-	 * Even memcg does not account for hugetlb, we still want to update
-	 * system-level stats via lruvec_stat_mod_folio. Return 0, and skip
-	 * charging the memcg.
-	 */
-	if (mem_cgroup_disabled() || !memcg_accounts_hugetlb() ||
-		!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
-		goto out;
-
-	if (charge_memcg(folio, memcg, gfp))
-		ret = -ENOMEM;
-
-out:
-	mem_cgroup_put(memcg);
-	return ret;
-}
-
 /**
  * mem_cgroup_swapin_charge_folio - Charge a newly allocated folio for swapin.
  * @folio: folio to charge.
-- 
2.53.0.310.g728cabbaf7-goog