[PATCH -next v3 00/19] mm: convert page cpupid functions to folios

[PATCH -next v3 00/19] mm: convert page cpupid functions to folios

[Kefeng Wang]

The cpupid(or access time) used by numa balancing is stored in flags
or _last_cpupid(if LAST_CPUPID_NOT_IN_PAGE_FLAGS) of page, this is to
convert page cpupid to folio cpupid, a new _last_cpupid is added into
folio, which make us to use folio->_last_cpupid directly, and the
page cpupid functions are converted to folio ones.

  page_cpupid_last()		-> folio_last_cpupid()
  xchg_page_access_time()	-> folio_xchg_access_time()
  page_cpupid_xchg_last()	-> folio_xchg_last_cpupid()

v3:
- fix finish_mkwrite_fault built warning reported-by lkp
- address the wp_page_reuse() comment of Matthew, also update
  changelog of change_pte_range() and wp_page_reuse() a bit
- rebased on next-20231018

v2:
- add virtual into folio too
- re-write and split patches to make them easier to review
- rename to folio_last_cpupid/folio_xchg_last_cpupid/folio_xchg_access_time
- rebased on next-20231013

v1:
- drop inappropriate page_cpupid_reset_last conversion from RFC
- rebased on next-20231009

Kefeng Wang (19):
  mm_types: add virtual and _last_cpupid into struct folio
  mm: add folio_last_cpupid()
  mm: memory: use folio_last_cpupid() in do_numa_page()
  mm: huge_memory: use folio_last_cpupid() in do_huge_pmd_numa_page()
  mm: huge_memory: use folio_last_cpupid() in __split_huge_page_tail()
  mm: remove page_cpupid_last()
  mm: add folio_xchg_access_time()
  sched/fair: use folio_xchg_access_time() in numa_hint_fault_latency()
  mm: mprotect: use a folio in change_pte_range()
  mm: huge_memory: use a folio in change_huge_pmd()
  mm: remove xchg_page_access_time()
  mm: add folio_xchg_last_cpupid()
  sched/fair: use folio_xchg_last_cpupid() in
    should_numa_migrate_memory()
  mm: migrate: use folio_xchg_last_cpupid() in folio_migrate_flags()
  mm: huge_memory: use folio_xchg_last_cpupid() in
    __split_huge_page_tail()
  mm: make finish_mkwrite_fault() static
  mm: convert wp_page_reuse() and finish_mkwrite_fault() to take a folio
  mm: use folio_xchg_last_cpupid() in wp_page_reuse()
  mm: remove page_cpupid_xchg_last()

 include/linux/mm.h       | 30 +++++++++++++++---------------
 include/linux/mm_types.h | 22 ++++++++++++++++++----
 kernel/sched/fair.c      |  4 ++--
 mm/huge_memory.c         | 17 +++++++++--------
 mm/memory.c              | 38 ++++++++++++++++++++------------------
 mm/migrate.c             |  8 ++++----
 mm/mmzone.c              |  6 +++---
 mm/mprotect.c            | 16 +++++++++-------
 8 files changed, 80 insertions(+), 61 deletions(-)

-- 
2.27.0

[PATCH v3 01/19] mm_types: add virtual and _last_cpupid into struct folio

[Kefeng Wang]

If WANT_PAGE_VIRTUAL and LAST_CPUPID_NOT_IN_PAGE_FLAGS defined,
the 'virtual' and '_last_cpupid' are in struct page, and since
_last_cpupid is used by numa balancing feature, it is better to
move it before KMSAN metadata from struct page, also add them
into struct folio to make us to access them from folio directly.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/mm_types.h | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index cc8bb767c003..34466be945a9 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -199,6 +199,10 @@ struct page {
 					   not kmapped, ie. highmem) */
 #endif /* WANT_PAGE_VIRTUAL */
 
+#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
+	int _last_cpupid;
+#endif
+
 #ifdef CONFIG_KMSAN
 	/*
 	 * KMSAN metadata for this page:
@@ -210,10 +214,6 @@ struct page {
 	struct page *kmsan_shadow;
 	struct page *kmsan_origin;
 #endif
-
-#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
-	int _last_cpupid;
-#endif
 } _struct_page_alignment;
 
 /*
@@ -272,6 +272,8 @@ typedef struct {
  * @_refcount: Do not access this member directly.  Use folio_ref_count()
  *    to find how many references there are to this folio.
  * @memcg_data: Memory Control Group data.
+ * @virtual: Virtual address in the kernel direct map.
+ * @_last_cpupid: IDs of last CPU and last process that accessed the folio.
  * @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
  * @_nr_pages_mapped: Do not use directly, call folio_mapcount().
  * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
@@ -317,6 +319,12 @@ struct folio {
 			atomic_t _refcount;
 #ifdef CONFIG_MEMCG
 			unsigned long memcg_data;
+#endif
+#if defined(WANT_PAGE_VIRTUAL)
+			void *virtual;
+#endif
+#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
+			int _last_cpupid;
 #endif
 	/* private: the union with struct page is transitional */
 		};
@@ -373,6 +381,12 @@ FOLIO_MATCH(_refcount, _refcount);
 #ifdef CONFIG_MEMCG
 FOLIO_MATCH(memcg_data, memcg_data);
 #endif
+#if defined(WANT_PAGE_VIRTUAL)
+FOLIO_MATCH(virtual, virtual);
+#endif
+#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
+FOLIO_MATCH(_last_cpupid, _last_cpupid);
+#endif
 #undef FOLIO_MATCH
 #define FOLIO_MATCH(pg, fl)						\
 	static_assert(offsetof(struct folio, fl) ==			\
-- 
2.27.0

[PATCH v3 02/19] mm: add folio_last_cpupid()

[Kefeng Wang]

Add folio_last_cpupid() wrapper, which is required to convert
page_cpupid_last() to folio vertion later in the series.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/mm.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d005beccaa5d..1c393a72037b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1794,6 +1794,11 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
+static inline int folio_last_cpupid(struct folio *folio)
+{
+	return page_cpupid_last(&folio->page);
+}
+
 #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 /*
-- 
2.27.0

[PATCH v3 03/19] mm: memory: use folio_last_cpupid() in do_numa_page()

[Kefeng Wang]

Convert to use folio_last_cpupid() in do_numa_page().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index c4b4aa4c1180..a1cf25a3ff16 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4861,7 +4861,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	    !node_is_toptier(nid))
 		last_cpupid = (-1 & LAST_CPUPID_MASK);
 	else
-		last_cpupid = page_cpupid_last(&folio->page);
+		last_cpupid = folio_last_cpupid(folio);
 	target_nid = numa_migrate_prep(folio, vma, vmf->address, nid, &flags);
 	if (target_nid == NUMA_NO_NODE) {
 		folio_put(folio);
-- 
2.27.0

[PATCH v3 04/19] mm: huge_memory: use folio_last_cpupid() in do_huge_pmd_numa_page()

[Kefeng Wang]

Convert to use folio_last_cpupid() in do_huge_pmd_numa_page().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/huge_memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c9cbcbf6697e..f9571bf92603 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1562,7 +1562,7 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
 	 * to record page access time.  So use default value.
 	 */
 	if (node_is_toptier(nid))
-		last_cpupid = page_cpupid_last(&folio->page);
+		last_cpupid = folio_last_cpupid(folio);
 	target_nid = numa_migrate_prep(folio, vma, haddr, nid, &flags);
 	if (target_nid == NUMA_NO_NODE) {
 		folio_put(folio);
-- 
2.27.0

[PATCH v3 05/19] mm: huge_memory: use folio_last_cpupid() in __split_huge_page_tail()

[Kefeng Wang]

Convert to use folio_last_cpupid() in __split_huge_page_tail().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/huge_memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f9571bf92603..5455dfe4c3c7 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2514,7 +2514,7 @@ static void __split_huge_page_tail(struct folio *folio, int tail,
 	if (page_is_idle(head))
 		set_page_idle(page_tail);
 
-	page_cpupid_xchg_last(page_tail, page_cpupid_last(head));
+	page_cpupid_xchg_last(page_tail, folio_last_cpupid(folio));
 
 	/*
 	 * always add to the tail because some iterators expect new
-- 
2.27.0

[PATCH v3 06/19] mm: remove page_cpupid_last()

[Kefeng Wang]

Since all calls use folio_last_cpupid(), remove page_cpupid_last().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/mm.h | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1c393a72037b..1d56a818b212 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1700,18 +1700,18 @@ static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
 	return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK);
 }
 
-static inline int page_cpupid_last(struct page *page)
+static inline int folio_last_cpupid(struct folio *folio)
 {
-	return page->_last_cpupid;
+	return folio->_last_cpupid;
 }
 static inline void page_cpupid_reset_last(struct page *page)
 {
 	page->_last_cpupid = -1 & LAST_CPUPID_MASK;
 }
 #else
-static inline int page_cpupid_last(struct page *page)
+static inline int folio_last_cpupid(struct folio *folio)
 {
-	return (page->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
+	return (folio->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
 }
 
 extern int page_cpupid_xchg_last(struct page *page, int cpupid);
@@ -1750,9 +1750,9 @@ static inline int xchg_page_access_time(struct page *page, int time)
 	return 0;
 }
 
-static inline int page_cpupid_last(struct page *page)
+static inline int folio_last_cpupid(struct folio *folio)
 {
-	return page_to_nid(page); /* XXX */
+	return folio_nid(folio); /* XXX */
 }
 
 static inline int cpupid_to_nid(int cpupid)
@@ -1794,11 +1794,6 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
-static inline int folio_last_cpupid(struct folio *folio)
-{
-	return page_cpupid_last(&folio->page);
-}
-
 #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 /*
-- 
2.27.0

[PATCH v3 07/19] mm: add folio_xchg_access_time()

[Kefeng Wang]

Add folio_xchg_access_time() wrapper, which is required to convert
xchg_page_access_time() to folio vertion later in the series.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/mm.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1d56a818b212..1238ab784d8b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1794,6 +1794,11 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
+static inline int folio_xchg_access_time(struct folio *folio, int time)
+{
+	return xchg_page_access_time(&folio->page, time);
+}
+
 #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 /*
-- 
2.27.0

[PATCH v3 08/19] sched/fair: use folio_xchg_access_time() in numa_hint_fault_latency()

[Kefeng Wang]

Convert to use folio_xchg_access_time() in numa_hint_fault_latency().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c50271f39d91..b8c52893b3d9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1766,7 +1766,7 @@ static int numa_hint_fault_latency(struct folio *folio)
 	int last_time, time;
 
 	time = jiffies_to_msecs(jiffies);
-	last_time = xchg_page_access_time(&folio->page, time);
+	last_time = folio_xchg_access_time(folio, time);
 
 	return (time - last_time) & PAGE_ACCESS_TIME_MASK;
 }
-- 
2.27.0

[PATCH v3 09/19] mm: mprotect: use a folio in change_pte_range()

[Kefeng Wang]

Use a folio in change_pte_range() to save three compound_head() calls.
Since now only normal and PMD-mapped page is handled by numa balancing,
it is enough to only update the entire folio's access time.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/mprotect.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c
index f1dc8f8c84ef..81991102f785 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -114,7 +114,7 @@ static long change_pte_range(struct mmu_gather *tlb,
 			 * pages. See similar comment in change_huge_pmd.
 			 */
 			if (prot_numa) {
-				struct page *page;
+				struct folio *folio;
 				int nid;
 				bool toptier;
 
@@ -122,13 +122,14 @@ static long change_pte_range(struct mmu_gather *tlb,
 				if (pte_protnone(oldpte))
 					continue;
 
-				page = vm_normal_page(vma, addr, oldpte);
-				if (!page || is_zone_device_page(page) || PageKsm(page))
+				folio = vm_normal_folio(vma, addr, oldpte);
+				if (!folio || folio_is_zone_device(folio) ||
+				    folio_test_ksm(folio))
 					continue;
 
 				/* Also skip shared copy-on-write pages */
 				if (is_cow_mapping(vma->vm_flags) &&
-				    page_count(page) != 1)
+				    folio_ref_count(folio) != 1)
 					continue;
 
 				/*
@@ -136,14 +137,15 @@ static long change_pte_range(struct mmu_gather *tlb,
 				 * it cannot move them all from MIGRATE_ASYNC
 				 * context.
 				 */
-				if (page_is_file_lru(page) && PageDirty(page))
+				if (folio_is_file_lru(folio) &&
+				    folio_test_dirty(folio))
 					continue;
 
 				/*
 				 * Don't mess with PTEs if page is already on the node
 				 * a single-threaded process is running on.
 				 */
-				nid = page_to_nid(page);
+				nid = folio_nid(folio);
 				if (target_node == nid)
 					continue;
 				toptier = node_is_toptier(nid);
@@ -157,7 +159,7 @@ static long change_pte_range(struct mmu_gather *tlb,
 					continue;
 				if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
 				    !toptier)
-					xchg_page_access_time(page,
+					folio_xchg_access_time(folio,
 						jiffies_to_msecs(jiffies));
 			}
 
-- 
2.27.0

[PATCH v3 10/19] mm: huge_memory: use a folio in change_huge_pmd()

[Kefeng Wang]

Use a folio in change_huge_pmd(), which helps to remove last
xchg_page_access_time() caller.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/huge_memory.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5455dfe4c3c7..f01f345141da 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1856,7 +1856,7 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
 	if (is_swap_pmd(*pmd)) {
 		swp_entry_t entry = pmd_to_swp_entry(*pmd);
-		struct page *page = pfn_swap_entry_to_page(entry);
+		struct folio *folio = page_folio(pfn_swap_entry_to_page(entry));
 		pmd_t newpmd;
 
 		VM_BUG_ON(!is_pmd_migration_entry(*pmd));
@@ -1865,7 +1865,7 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			 * A protection check is difficult so
 			 * just be safe and disable write
 			 */
-			if (PageAnon(page))
+			if (folio_test_anon(folio))
 				entry = make_readable_exclusive_migration_entry(swp_offset(entry));
 			else
 				entry = make_readable_migration_entry(swp_offset(entry));
@@ -1887,7 +1887,7 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 #endif
 
 	if (prot_numa) {
-		struct page *page;
+		struct folio *folio;
 		bool toptier;
 		/*
 		 * Avoid trapping faults against the zero page. The read-only
@@ -1900,8 +1900,8 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		if (pmd_protnone(*pmd))
 			goto unlock;
 
-		page = pmd_page(*pmd);
-		toptier = node_is_toptier(page_to_nid(page));
+		folio = page_folio(pmd_page(*pmd));
+		toptier = node_is_toptier(folio_nid(folio));
 		/*
 		 * Skip scanning top tier node if normal numa
 		 * balancing is disabled
@@ -1912,7 +1912,8 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 
 		if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
 		    !toptier)
-			xchg_page_access_time(page, jiffies_to_msecs(jiffies));
+			folio_xchg_access_time(folio,
+					       jiffies_to_msecs(jiffies));
 	}
 	/*
 	 * In case prot_numa, we are under mmap_read_lock(mm). It's critical
-- 
2.27.0

[PATCH v3 11/19] mm: remove xchg_page_access_time()

[Kefeng Wang]

Since all calls use folio_xchg_access_time(), remove
xchg_page_access_time().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/mm.h | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1238ab784d8b..8a2ff345338b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1722,11 +1722,12 @@ static inline void page_cpupid_reset_last(struct page *page)
 }
 #endif /* LAST_CPUPID_NOT_IN_PAGE_FLAGS */
 
-static inline int xchg_page_access_time(struct page *page, int time)
+static inline int folio_xchg_access_time(struct folio *folio, int time)
 {
 	int last_time;
 
-	last_time = page_cpupid_xchg_last(page, time >> PAGE_ACCESS_TIME_BUCKETS);
+	last_time = page_cpupid_xchg_last(&folio->page,
+					  time >> PAGE_ACCESS_TIME_BUCKETS);
 	return last_time << PAGE_ACCESS_TIME_BUCKETS;
 }
 
@@ -1745,7 +1746,7 @@ static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
 	return page_to_nid(page); /* XXX */
 }
 
-static inline int xchg_page_access_time(struct page *page, int time)
+static inline int folio_xchg_access_time(struct folio *folio, int time)
 {
 	return 0;
 }
@@ -1794,11 +1795,6 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
-static inline int folio_xchg_access_time(struct folio *folio, int time)
-{
-	return xchg_page_access_time(&folio->page, time);
-}
-
 #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 /*
-- 
2.27.0

[PATCH v3 12/19] mm: add folio_xchg_last_cpupid()

[Kefeng Wang]

Add folio_xchg_last_cpupid() wrapper, which is required to convert
page_cpupid_xchg_last() to folio vertion later in the series.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/mm.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8a2ff345338b..8229137e093b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1795,6 +1795,11 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
+static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid)
+{
+	return page_cpupid_xchg_last(&folio->page, cpupid);
+}
+
 #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 /*
-- 
2.27.0

[PATCH v3 13/19] sched/fair: use folio_xchg_last_cpupid() in should_numa_migrate_memory()

[Kefeng Wang]

Convert to use folio_xchg_last_cpupid() in should_numa_migrate_memory().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b8c52893b3d9..bafac84f7be9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1862,7 +1862,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio,
 	}
 
 	this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid);
-	last_cpupid = page_cpupid_xchg_last(&folio->page, this_cpupid);
+	last_cpupid = folio_xchg_last_cpupid(folio, this_cpupid);
 
 	if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) &&
 	    !node_is_toptier(src_nid) && !cpupid_valid(last_cpupid))
-- 
2.27.0

[PATCH v3 14/19] mm: migrate: use folio_xchg_last_cpupid() in folio_migrate_flags()

[Kefeng Wang]

Convert to use folio_xchg_last_cpupid() in folio_migrate_flags(), also
directly use folio_nid() instead of page_to_nid(&folio->page).

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/migrate.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 5348827bd958..821c42d61ed0 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -588,20 +588,20 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio)
 	 * Copy NUMA information to the new page, to prevent over-eager
 	 * future migrations of this same page.
 	 */
-	cpupid = page_cpupid_xchg_last(&folio->page, -1);
+	cpupid = folio_xchg_last_cpupid(folio, -1);
 	/*
 	 * For memory tiering mode, when migrate between slow and fast
 	 * memory node, reset cpupid, because that is used to record
 	 * page access time in slow memory node.
 	 */
 	if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) {
-		bool f_toptier = node_is_toptier(page_to_nid(&folio->page));
-		bool t_toptier = node_is_toptier(page_to_nid(&newfolio->page));
+		bool f_toptier = node_is_toptier(folio_nid(folio));
+		bool t_toptier = node_is_toptier(folio_nid(newfolio));
 
 		if (f_toptier != t_toptier)
 			cpupid = -1;
 	}
-	page_cpupid_xchg_last(&newfolio->page, cpupid);
+	folio_xchg_last_cpupid(newfolio, cpupid);
 
 	folio_migrate_ksm(newfolio, folio);
 	/*
-- 
2.27.0

[PATCH v3 15/19] mm: huge_memory: use folio_xchg_last_cpupid() in __split_huge_page_tail()

[Kefeng Wang]

Convert to use folio_xchg_last_cpupid() in __split_huge_page_tail().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/huge_memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f01f345141da..f31f02472396 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2515,7 +2515,7 @@ static void __split_huge_page_tail(struct folio *folio, int tail,
 	if (page_is_idle(head))
 		set_page_idle(page_tail);
 
-	page_cpupid_xchg_last(page_tail, folio_last_cpupid(folio));
+	folio_xchg_last_cpupid(new_folio, folio_last_cpupid(folio));
 
 	/*
 	 * always add to the tail because some iterators expect new
-- 
2.27.0

[PATCH v3 16/19] mm: make finish_mkwrite_fault() static

[Kefeng Wang]

Make finish_mkwrite_fault static since it is not used outside of
memory.c.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/mm.h | 1 -
 mm/memory.c        | 2 +-
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8229137e093b..70eae2e7d5e5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1346,7 +1346,6 @@ void set_pte_range(struct vm_fault *vmf, struct folio *folio,
 		struct page *page, unsigned int nr, unsigned long addr);
 
 vm_fault_t finish_fault(struct vm_fault *vmf);
-vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
 #endif
 
 /*
diff --git a/mm/memory.c b/mm/memory.c
index a1cf25a3ff16..b6cc24257683 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3272,7 +3272,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
  * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before
  * we acquired PTE lock.
  */
-vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf)
+static vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf)
 {
 	WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED));
 	vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address,
-- 
2.27.0

[PATCH v3 17/19] mm: convert wp_page_reuse() and finish_mkwrite_fault() to take a folio

[Kefeng Wang]

Saves one compound_head() call, also in preparation for
page_cpupid_xchg_last() conversion.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/memory.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index b6cc24257683..037da118f1d1 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3018,7 +3018,7 @@ static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf)
  * case, all we need to do here is to mark the page as writable and update
  * any related book-keeping.
  */
-static inline void wp_page_reuse(struct vm_fault *vmf)
+static inline void wp_page_reuse(struct vm_fault *vmf, struct folio *folio)
 	__releases(vmf->ptl)
 {
 	struct vm_area_struct *vma = vmf->vma;
@@ -3026,7 +3026,7 @@ static inline void wp_page_reuse(struct vm_fault *vmf)
 	pte_t entry;
 
 	VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE));
-	VM_BUG_ON(page && PageAnon(page) && !PageAnonExclusive(page));
+	VM_BUG_ON(folio && folio_test_anon(folio) && !PageAnonExclusive(page));
 
 	/*
 	 * Clear the pages cpupid information as the existing
@@ -3261,6 +3261,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
  *			  writeable once the page is prepared
  *
  * @vmf: structure describing the fault
+ * @folio: the folio of vmf->page
  *
  * This function handles all that is needed to finish a write page fault in a
  * shared mapping due to PTE being read-only once the mapped page is prepared.
@@ -3272,7 +3273,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
  * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before
  * we acquired PTE lock.
  */
-static vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf)
+static vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf, struct folio *folio)
 {
 	WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED));
 	vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address,
@@ -3288,7 +3289,7 @@ static vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf)
 		pte_unmap_unlock(vmf->pte, vmf->ptl);
 		return VM_FAULT_NOPAGE;
 	}
-	wp_page_reuse(vmf);
+	wp_page_reuse(vmf, folio);
 	return 0;
 }
 
@@ -3312,9 +3313,9 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf)
 		ret = vma->vm_ops->pfn_mkwrite(vmf);
 		if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))
 			return ret;
-		return finish_mkwrite_fault(vmf);
+		return finish_mkwrite_fault(vmf, NULL);
 	}
-	wp_page_reuse(vmf);
+	wp_page_reuse(vmf, NULL);
 	return 0;
 }
 
@@ -3342,14 +3343,14 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio)
 			folio_put(folio);
 			return tmp;
 		}
-		tmp = finish_mkwrite_fault(vmf);
+		tmp = finish_mkwrite_fault(vmf, folio);
 		if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
 			folio_unlock(folio);
 			folio_put(folio);
 			return tmp;
 		}
 	} else {
-		wp_page_reuse(vmf);
+		wp_page_reuse(vmf, folio);
 		folio_lock(folio);
 	}
 	ret |= fault_dirty_shared_page(vmf);
@@ -3494,7 +3495,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
 			pte_unmap_unlock(vmf->pte, vmf->ptl);
 			return 0;
 		}
-		wp_page_reuse(vmf);
+		wp_page_reuse(vmf, folio);
 		return 0;
 	}
 	/*
-- 
2.27.0

[PATCH v3 18/19] mm: use folio_xchg_last_cpupid() in wp_page_reuse()

[Kefeng Wang]

Convert to use folio_xchg_last_cpupid() in wp_page_reuse(), and remove
page variable. Since now only normal and PMD-mapped page is handled by
numa balancing, it's enough to only update the entire folio's last cpupid.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/memory.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 037da118f1d1..4f0dfbd5e4bf 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3022,19 +3022,20 @@ static inline void wp_page_reuse(struct vm_fault *vmf, struct folio *folio)
 	__releases(vmf->ptl)
 {
 	struct vm_area_struct *vma = vmf->vma;
-	struct page *page = vmf->page;
 	pte_t entry;
 
 	VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE));
-	VM_BUG_ON(folio && folio_test_anon(folio) && !PageAnonExclusive(page));
 
-	/*
-	 * Clear the pages cpupid information as the existing
-	 * information potentially belongs to a now completely
-	 * unrelated process.
-	 */
-	if (page)
-		page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1);
+	if (folio) {
+		VM_BUG_ON(folio_test_anon(folio) &&
+			  !PageAnonExclusive(vmf->page));
+		/*
+		 * Clear the folio's cpupid information as the existing
+		 * information potentially belongs to a now completely
+		 * unrelated process.
+		 */
+		folio_xchg_last_cpupid(folio, (1 << LAST_CPUPID_SHIFT) - 1);
+	}
 
 	flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
 	entry = pte_mkyoung(vmf->orig_pte);
-- 
2.27.0

[PATCH v3 19/19] mm: remove page_cpupid_xchg_last()

[Kefeng Wang]

Since all calls use folio_xchg_last_cpupid(), remove
page_cpupid_xchg_last().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/mm.h | 19 +++++++------------
 mm/mmzone.c        |  6 +++---
 2 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 70eae2e7d5e5..287d52ace444 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1694,9 +1694,9 @@ static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
 
 #define cpupid_match_pid(task, cpupid) __cpupid_match_pid(task->pid, cpupid)
 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
-static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
+static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid)
 {
-	return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK);
+	return xchg(&folio->_last_cpupid, cpupid & LAST_CPUPID_MASK);
 }
 
 static inline int folio_last_cpupid(struct folio *folio)
@@ -1713,7 +1713,7 @@ static inline int folio_last_cpupid(struct folio *folio)
 	return (folio->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
 }
 
-extern int page_cpupid_xchg_last(struct page *page, int cpupid);
+int folio_xchg_last_cpupid(struct folio *folio, int cpupid);
 
 static inline void page_cpupid_reset_last(struct page *page)
 {
@@ -1725,8 +1725,8 @@ static inline int folio_xchg_access_time(struct folio *folio, int time)
 {
 	int last_time;
 
-	last_time = page_cpupid_xchg_last(&folio->page,
-					  time >> PAGE_ACCESS_TIME_BUCKETS);
+	last_time = folio_xchg_last_cpupid(folio,
+					   time >> PAGE_ACCESS_TIME_BUCKETS);
 	return last_time << PAGE_ACCESS_TIME_BUCKETS;
 }
 
@@ -1740,9 +1740,9 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 	}
 }
 #else /* !CONFIG_NUMA_BALANCING */
-static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
+static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid)
 {
-	return page_to_nid(page); /* XXX */
+	return folio_nid(folio); /* XXX */
 }
 
 static inline int folio_xchg_access_time(struct folio *folio, int time)
@@ -1794,11 +1794,6 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
-static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid)
-{
-	return page_cpupid_xchg_last(&folio->page, cpupid);
-}
-
 #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 /*
diff --git a/mm/mmzone.c b/mm/mmzone.c
index 68e1511be12d..b594d3f268fe 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -93,19 +93,19 @@ void lruvec_init(struct lruvec *lruvec)
 }
 
 #if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
-int page_cpupid_xchg_last(struct page *page, int cpupid)
+int folio_xchg_last_cpupid(struct folio *folio, int cpupid)
 {
 	unsigned long old_flags, flags;
 	int last_cpupid;
 
-	old_flags = READ_ONCE(page->flags);
+	old_flags = READ_ONCE(folio->flags);
 	do {
 		flags = old_flags;
 		last_cpupid = (flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
 
 		flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
 		flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
-	} while (unlikely(!try_cmpxchg(&page->flags, &old_flags, flags)));
+	} while (unlikely(!try_cmpxchg(&folio->flags, &old_flags, flags)));
 
 	return last_cpupid;
 }
-- 
2.27.0