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AJvYcCUSJdETqD9RsiDPR9IoDXapx9OTZbL2GUu5pNAPe2ycE6F/B/rEtsFllgBnBAI26BFyUhiMxFQfVT1QTng=@vger.kernel.org X-Gm-Message-State: AOJu0YyBY6/2+2+GbgehSCZclMmQhEZ/+wF6BGdMbLJDvqJgRfygeYvr 19+xhRGvzmcEzKGAit+SxTrYEtvWBL2LCw7RPAUFAeh5tWRzT6fgtcSm9dQnc0YdaoNvsGJlsMd iUZUMXEBu8cKHXSUeDq3fheIA2Q== X-Received: from pgax34.prod.google.com ([2002:a05:6a02:2e62:b0:c65:c5fc:1707]) (user=ackerleytng job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:c702:b0:38e:9e77:c9e5 with SMTP id adf61e73a8af0-3944886d6f3mr806864637.72.1770856652565; Wed, 11 Feb 2026 16:37:32 -0800 (PST) Date: Wed, 11 Feb 2026 16:37:15 -0800 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.53.0.310.g728cabbaf7-goog Message-ID: <24f2962dcbd369a2e01590aca0a365e5118778fe.1770854662.git.ackerleytng@google.com> Subject: [RFC PATCH v1 4/7] Revert "memcg/hugetlb: remove memcg hugetlb try-commit-cancel protocol" From: Ackerley Tng To: akpm@linux-foundation.org, dan.j.williams@intel.com, david@kernel.org, fvdl@google.com, hannes@cmpxchg.org, jgg@nvidia.com, jiaqiyan@google.com, jthoughton@google.com, kalyazin@amazon.com, mhocko@kernel.org, michael.roth@amd.com, muchun.song@linux.dev, osalvador@suse.de, pasha.tatashin@soleen.com, pbonzini@redhat.com, peterx@redhat.com, pratyush@kernel.org, rick.p.edgecombe@intel.com, rientjes@google.com, roman.gushchin@linux.dev, seanjc@google.com, shakeel.butt@linux.dev, shivankg@amd.com, vannapurve@google.com, yan.y.zhao@intel.com Cc: ackerleytng@google.com, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This reverts commit 1d8f136a421f26747e58c01281cba5bffae8d289. Restore try-commit-cancel protocol for memory charging for HugeTLB, to be used in later patches. Signed-off-by: Ackerley Tng --- include/linux/memcontrol.h | 22 +++++++++++++ mm/memcontrol.c | 65 ++++++++++++++++++++++++++++++++++++-- 2 files changed, 84 insertions(+), 3 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index f29d4969c0c36..59eab4caa01fa 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -639,6 +639,8 @@ static inline bool mem_cgroup_below_min(struct mem_cgro= up *target, page_counter_read(&memcg->memory); } =20 +void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memc= g); + int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t g= fp); =20 /** @@ -663,6 +665,9 @@ static inline int mem_cgroup_charge(struct folio *folio= , struct mm_struct *mm, return __mem_cgroup_charge(folio, mm, gfp); } =20 +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); =20 int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *= mm, @@ -691,6 +696,7 @@ static inline void mem_cgroup_uncharge_folios(struct fo= lio_batch *folios) __mem_cgroup_uncharge_folios(folios); } =20 +void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pa= ges); void mem_cgroup_replace_folio(struct folio *old, struct folio *new); void mem_cgroup_migrate(struct folio *old, struct folio *new); =20 @@ -1135,12 +1141,23 @@ static inline bool mem_cgroup_below_min(struct mem_= cgroup *target, return false; } =20 +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; } =20 +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; @@ -1160,6 +1177,11 @@ static inline void mem_cgroup_uncharge_folios(struct= folio_batch *folios) { } =20 +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 36ab9897b61b2..70d762ba465b1 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2561,6 +2561,21 @@ static inline int try_charge(struct mem_cgroup *memc= g, gfp_t gfp_mask, return try_charge_memcg(memcg, gfp_mask, nr_pages); } =20 +/** + * 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_pa= ges) +{ + 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); @@ -2574,6 +2589,18 @@ static void commit_charge(struct folio *folio, struc= t mem_cgroup *memcg) folio->memcg_data =3D (unsigned long)memcg; } =20 +/** + * 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 *memc= g) +{ + css_get(&memcg->css); + commit_charge(folio, memcg); + memcg1_commit_charge(folio, memcg); +} + #ifdef CONFIG_MEMCG_NMI_SAFETY_REQUIRES_ATOMIC static inline void account_slab_nmi_safe(struct mem_cgroup *memcg, struct pglist_data *pgdat, @@ -4777,9 +4804,7 @@ static int charge_memcg(struct folio *folio, struct m= em_cgroup *memcg, if (ret) goto out; =20 - css_get(&memcg->css); - commit_charge(folio, memcg); - memcg1_commit_charge(folio, memcg); + mem_cgroup_commit_charge(folio, memcg); out: return ret; } @@ -4796,6 +4821,40 @@ int __mem_cgroup_charge(struct folio *folio, struct = mm_struct *mm, gfp_t gfp) return ret; } =20 +/** + * mem_cgroup_hugetlb_try_charge - try to charge the memcg for a hugetlb f= olio + * @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 t= he + * folio, we should instead call mem_cgroup_cancel_charge() to undo the ef= fect + * 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 allocati= on, + * 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 --=20 2.53.0.310.g728cabbaf7-goog