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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 3/7] mm: memcg: make memcg huge page split support any order split.
Date:   Tue, 28 Mar 2023 21:17:08 -0400
Message-Id: <20230329011712.3242298-4-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>
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From: Zi Yan <ziy@nvidia.com>

It sets memcg information for the pages after the split. A new parameter
new_order is added to tell the order of subpages in the new page, always 0
for now. It prepares for upcoming changes to support split huge page to
any lower order.

Signed-off-by: Zi Yan <ziy@nvidia.com>
---
 include/linux/memcontrol.h |  4 ++--
 mm/huge_memory.c           |  2 +-
 mm/memcontrol.c            | 11 ++++++-----
 mm/page_alloc.c            |  4 ++--
 4 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e06a61ea4fc1..1633c00fe393 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, int order);
+void split_page_memcg(struct page *head, int old_order, int new_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, int order)
+static inline void split_page_memcg(struct page *head, int old_order, int =
new_order)
 {
 }
=20
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a21921c90b21..106cde74d933 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2516,7 +2516,7 @@ static void __split_huge_page(struct page *page, stru=
ct list_head *list,
 	int i;
=20
 	/* complete memcg works before add pages to LRU */
-	split_page_memcg(head, order);
+	split_page_memcg(head, order, 0);
=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 cab2828e188d..93ae37f90c84 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3414,23 +3414,24 @@ 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, int order)
+void split_page_memcg(struct page *head, int old_order, int new_order)
 {
 	struct folio *folio =3D page_folio(head);
 	struct mem_cgroup *memcg =3D folio_memcg(folio);
 	int i;
-	unsigned int nr =3D 1 << order;
+	unsigned int old_nr =3D 1 << old_order;
+	unsigned int new_nr =3D 1 << new_order;
=20
 	if (mem_cgroup_disabled() || !memcg)
 		return;
=20
-	for (i =3D 1; i < nr; i++)
+	for (i =3D new_nr; i < old_nr; i +=3D new_nr)
 		folio_page(folio, i)->memcg_data =3D folio->memcg_data;
=20
 	if (folio_memcg_kmem(folio))
-		obj_cgroup_get_many(__folio_objcg(folio), nr - 1);
+		obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1);
 	else
-		css_get_many(&memcg->css, nr - 1);
+		css_get_many(&memcg->css, old_nr / new_nr - 1);
 }
=20
 #ifdef CONFIG_SWAP
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d537828bc4be..ef559795525b 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, order);
-	split_page_memcg(page, order);
+	split_page_memcg(page, order, 0);
 }
 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, order);
-		split_page_memcg(page, order);
+		split_page_memcg(page, order, 0);
 		while (page < --last)
 			set_page_refcounted(last);
=20
--=20
2.39.2