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From:   Zi Yan <zi.yan@sent.com>
To:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Yang Shi <shy828301@gmail.com>, Yu Zhao <yuzhao@google.com>,
        linux-mm@kvack.org
Cc:     Zi Yan <ziy@nvidia.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Ryan Roberts <ryan.roberts@arm.com>,
        =?UTF-8?q?Michal=20Koutn=C3=BD?= <mkoutny@suse.com>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        "Zach O'Keefe" <zokeefe@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: [PATCH v2 1/7] mm/memcg: use order instead of nr in split_page_memcg()
Date:   Tue, 28 Mar 2023 21:17:06 -0400
Message-Id: <20230329011712.3242298-2-zi.yan@sent.com>
In-Reply-To: <20230329011712.3242298-1-zi.yan@sent.com>
References: <20230329011712.3242298-1-zi.yan@sent.com>
Reply-To: Zi Yan <ziy@nvidia.com>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
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From: Zi Yan <ziy@nvidia.com>

We do not have non power of two pages, using nr is error prone if nr
is not power-of-two. Use page order instead.

Signed-off-by: Zi Yan <ziy@nvidia.com>
---
 include/linux/memcontrol.h | 4 ++--
 mm/huge_memory.c           | 3 ++-
 mm/memcontrol.c            | 3 ++-
 mm/page_alloc.c            | 4 ++--
 4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index aa69ea98e2d8..e06a61ea4fc1 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1151,7 +1151,7 @@ static inline void memcg_memory_event_mm(struct mm_st=
ruct *mm,
 	rcu_read_unlock();
 }
=20
-void split_page_memcg(struct page *head, unsigned int nr);
+void split_page_memcg(struct page *head, int order);
=20
 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 						gfp_t gfp_mask,
@@ -1588,7 +1588,7 @@ void count_memcg_event_mm(struct mm_struct *mm, enum =
vm_event_item idx)
 {
 }
=20
-static inline void split_page_memcg(struct page *head, unsigned int nr)
+static inline void split_page_memcg(struct page *head, int order)
 {
 }
=20
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 81a5689806af..3bb003eb80a3 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2512,10 +2512,11 @@ static void __split_huge_page(struct page *page, st=
ruct list_head *list,
 	struct address_space *swap_cache =3D NULL;
 	unsigned long offset =3D 0;
 	unsigned int nr =3D thp_nr_pages(head);
+	int order =3D folio_order(folio);
 	int i;
=20
 	/* complete memcg works before add pages to LRU */
-	split_page_memcg(head, nr);
+	split_page_memcg(head, order);
=20
 	if (PageAnon(head) && PageSwapCache(head)) {
 		swp_entry_t entry =3D { .val =3D page_private(head) };
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 681e7528a714..cab2828e188d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3414,11 +3414,12 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg, =
size_t size)
 /*
  * Because page_memcg(head) is not set on tails, set it now.
  */
-void split_page_memcg(struct page *head, unsigned int nr)
+void split_page_memcg(struct page *head, int order)
 {
 	struct folio *folio =3D page_folio(head);
 	struct mem_cgroup *memcg =3D folio_memcg(folio);
 	int i;
+	unsigned int nr =3D 1 << order;
=20
 	if (mem_cgroup_disabled() || !memcg)
 		return;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0767dd6bc5ba..d84b121d1e03 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2781,7 +2781,7 @@ void split_page(struct page *page, unsigned int order)
 	for (i =3D 1; i < (1 << order); i++)
 		set_page_refcounted(page + i);
 	split_page_owner(page, 1 << order);
-	split_page_memcg(page, 1 << order);
+	split_page_memcg(page, order);
 }
 EXPORT_SYMBOL_GPL(split_page);
=20
@@ -4997,7 +4997,7 @@ static void *make_alloc_exact(unsigned long addr, uns=
igned int order,
 		struct page *last =3D page + nr;
=20
 		split_page_owner(page, 1 << order);
-		split_page_memcg(page, 1 << order);
+		split_page_memcg(page, order);
 		while (page < --last)
 			set_page_refcounted(last);
=20
--=20
2.39.2