[PATCH v2 0/7] page->index removals in mm

[PATCH v2 0/7] page->index removals in mm

[Matthew Wilcox (Oracle)]

As part of shrinking struct page, we need to stop using page->index.
This patchset gets rid of most of the remaining references to page->index
in mm, as well as increasing the number of functions which take a
const folio/page pointer.  It shrinks the text segment of mm by a few
hundred bytes in my test config, probably mostly from removing calls to
compound_head() in page_to_pgoff().

v2:
 - Add the bootmem patch to the series
   https://lore.kernel.org/linux-mm/20240912185602.2342148-1-willy@infradead.org/
 - Expand the scope of the page_address_in_vma() patch
 - Fix the build error reported by lkp@intel.com

v1 here: https://lore.kernel.org/linux-mm/20240723153503.1669586-1-willy@infradead.org/

Matthew Wilcox (Oracle) (7):
  mm: Convert page_to_pgoff() to page_pgoff()
  mm: Use page_pgoff() in more places
  mm: Renovate page_address_in_vma()
  mm: Mass constification of folio/page pointers
  bootmem: Stop using page->index
  mm: Remove references to page->index in huge_memory.c
  mm: Use page->private instead of page->index in percpu

 arch/x86/mm/init_64.c        |  9 ++++----
 include/linux/bootmem_info.h | 25 +++++++++++++-------
 include/linux/ksm.h          |  7 +++---
 include/linux/mm.h           |  2 +-
 include/linux/pagemap.h      | 31 +++++++++++++------------
 include/linux/rmap.h         | 17 ++++++--------
 kernel/futex/core.c          |  2 +-
 mm/bootmem_info.c            | 11 +++++----
 mm/huge_memory.c             | 18 +++++++--------
 mm/internal.h                |  9 ++++----
 mm/ksm.c                     | 12 +++++-----
 mm/memory-failure.c          | 30 ++++++++++++------------
 mm/mempolicy.c               |  2 +-
 mm/page_vma_mapped.c         |  8 +++----
 mm/percpu.c                  |  4 ++--
 mm/rmap.c                    | 44 +++++++++++++++++++++++-------------
 mm/sparse.c                  |  8 +++----
 mm/util.c                    |  2 +-
 18 files changed, 133 insertions(+), 108 deletions(-)

-- 
2.43.0

[PATCH v2 1/7] mm: Convert page_to_pgoff() to page_pgoff()

[Matthew Wilcox (Oracle)]

Change the function signature to pass in the folio as all three
callers have it.  This removes a reference to page->index, which we're
trying to get rid of.  And add kernel-doc.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/mm.h      |  2 +-
 include/linux/pagemap.h | 31 +++++++++++++++++--------------
 mm/memory-failure.c     |  4 ++--
 mm/rmap.c               |  2 +-
 4 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ecf63d2b0582..664c01850c87 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1895,7 +1895,7 @@ static inline unsigned long page_to_section(const struct page *page)
  *
  * Return: The Page Frame Number of the first page in the folio.
  */
-static inline unsigned long folio_pfn(struct folio *folio)
+static inline unsigned long folio_pfn(const struct folio *folio)
 {
 	return page_to_pfn(&folio->page);
 }
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 68a5f1ff3301..bcf0865a38ae 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -1011,22 +1011,25 @@ static inline struct folio *read_mapping_folio(struct address_space *mapping,
 	return read_cache_folio(mapping, index, NULL, file);
 }
 
-/*
- * Get the offset in PAGE_SIZE (even for hugetlb pages).
+/**
+ * page_pgoff - Calculate the logical page offset of this page.
+ * @folio: The folio containing this page.
+ * @page: The page which we need the offset of.
+ *
+ * For file pages, this is the offset from the beginning of the file
+ * in units of PAGE_SIZE.  For anonymous pages, this is the offset from
+ * the beginning of the anon_vma in units of PAGE_SIZE.  This will
+ * return nonsense for KSM pages.
+ *
+ * Context: Caller must have a reference on the folio or otherwise
+ * prevent it from being split or freed.
+ *
+ * Return: The offset in units of PAGE_SIZE.
  */
-static inline pgoff_t page_to_pgoff(struct page *page)
+static inline pgoff_t page_pgoff(const struct folio *folio,
+		const struct page *page)
 {
-	struct page *head;
-
-	if (likely(!PageTransTail(page)))
-		return page->index;
-
-	head = compound_head(page);
-	/*
-	 *  We don't initialize ->index for tail pages: calculate based on
-	 *  head page
-	 */
-	return head->index + page - head;
+	return folio->index + folio_page_idx(folio, page);
 }
 
 /*
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 96ce31e5a203..58a3d80961a4 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -617,7 +617,7 @@ static void collect_procs_anon(struct folio *folio, struct page *page,
 	if (av == NULL)	/* Not actually mapped anymore */
 		return;
 
-	pgoff = page_to_pgoff(page);
+	pgoff = page_pgoff(folio, page);
 	rcu_read_lock();
 	for_each_process(tsk) {
 		struct vm_area_struct *vma;
@@ -653,7 +653,7 @@ static void collect_procs_file(struct folio *folio, struct page *page,
 
 	i_mmap_lock_read(mapping);
 	rcu_read_lock();
-	pgoff = page_to_pgoff(page);
+	pgoff = page_pgoff(folio, page);
 	for_each_process(tsk) {
 		struct task_struct *t = task_early_kill(tsk, force_early);
 		unsigned long addr;
diff --git a/mm/rmap.c b/mm/rmap.c
index a8797d1b3d49..3b11f8b6935d 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1280,7 +1280,7 @@ static void __page_check_anon_rmap(struct folio *folio, struct page *page,
 	 */
 	VM_BUG_ON_FOLIO(folio_anon_vma(folio)->root != vma->anon_vma->root,
 			folio);
-	VM_BUG_ON_PAGE(page_to_pgoff(page) != linear_page_index(vma, address),
+	VM_BUG_ON_PAGE(page_pgoff(folio, page) != linear_page_index(vma, address),
 		       page);
 }
 
-- 
2.43.0

[PATCH v2 2/7] mm: Use page_pgoff() in more places

[Matthew Wilcox (Oracle)]

There are several places which currently open-code page_pgoff(),
convert them to call it.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 kernel/futex/core.c  | 2 +-
 mm/page_vma_mapped.c | 3 +--
 mm/rmap.c            | 4 +---
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/kernel/futex/core.c b/kernel/futex/core.c
index 136768ae2637..342dc4dd328b 100644
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -399,7 +399,7 @@ int get_futex_key(u32 __user *uaddr, unsigned int flags, union futex_key *key,
 
 		key->both.offset |= FUT_OFF_INODE; /* inode-based key */
 		key->shared.i_seq = get_inode_sequence_number(inode);
-		key->shared.pgoff = folio->index + folio_page_idx(folio, page);
+		key->shared.pgoff = page_pgoff(folio, page);
 		rcu_read_unlock();
 	}
 
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index ae5cc42aa208..ade3c6833587 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -328,7 +328,6 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 unsigned long page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
 {
 	struct folio *folio = page_folio(page);
-	pgoff_t pgoff = folio->index + folio_page_idx(folio, page);
 	struct page_vma_mapped_walk pvmw = {
 		.pfn = page_to_pfn(page),
 		.nr_pages = 1,
@@ -336,7 +335,7 @@ unsigned long page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
 		.flags = PVMW_SYNC,
 	};
 
-	pvmw.address = vma_address(vma, pgoff, 1);
+	pvmw.address = vma_address(vma, page_pgoff(folio, page), 1);
 	if (pvmw.address == -EFAULT)
 		goto out;
 	if (!page_vma_mapped_walk(&pvmw))
diff --git a/mm/rmap.c b/mm/rmap.c
index 3b11f8b6935d..90df71c640bf 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -775,7 +775,6 @@ static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags)
 unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 {
 	struct folio *folio = page_folio(page);
-	pgoff_t pgoff;
 
 	if (folio_test_anon(folio)) {
 		struct anon_vma *page__anon_vma = folio_anon_vma(folio);
@@ -793,8 +792,7 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 	}
 
 	/* The !page__anon_vma above handles KSM folios */
-	pgoff = folio->index + folio_page_idx(folio, page);
-	return vma_address(vma, pgoff, 1);
+	return vma_address(vma, page_pgoff(folio, page), 1);
 }
 
 /*
-- 
2.43.0

[PATCH v2 3/7] mm: Renovate page_address_in_vma()

[Matthew Wilcox (Oracle)]

This function doesn't modify any of its arguments, so if we make a few
other functions take const pointers, we can make page_address_in_vma()
take const pointers too.  All of its callers have the containing folio
already, so pass that in as an argument instead of recalculating it.
Also add kernel-doc

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/rmap.h |  7 ++-----
 mm/internal.h        |  4 ++--
 mm/ksm.c             |  7 +++----
 mm/memory-failure.c  |  2 +-
 mm/mempolicy.c       |  2 +-
 mm/rmap.c            | 27 ++++++++++++++++++++-------
 mm/util.c            |  2 +-
 7 files changed, 30 insertions(+), 21 deletions(-)

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index d5e93e44322e..78923015a2e8 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -728,11 +728,8 @@ page_vma_mapped_walk_restart(struct page_vma_mapped_walk *pvmw)
 }
 
 bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw);
-
-/*
- * Used by swapoff to help locate where page is expected in vma.
- */
-unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
+unsigned long page_address_in_vma(const struct folio *folio,
+		const struct page *, const struct vm_area_struct *);
 
 /*
  * Cleans the PTEs of shared mappings.
diff --git a/mm/internal.h b/mm/internal.h
index 93083bbeeefa..fffa9df41495 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -796,7 +796,7 @@ static inline bool free_area_empty(struct free_area *area, int migratetype)
 }
 
 /* mm/util.c */
-struct anon_vma *folio_anon_vma(struct folio *folio);
+struct anon_vma *folio_anon_vma(const struct folio *folio);
 
 #ifdef CONFIG_MMU
 void unmap_mapping_folio(struct folio *folio);
@@ -914,7 +914,7 @@ extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
  * If any page in this range is mapped by this VMA, return the first address
  * where any of these pages appear.  Otherwise, return -EFAULT.
  */
-static inline unsigned long vma_address(struct vm_area_struct *vma,
+static inline unsigned long vma_address(const struct vm_area_struct *vma,
 		pgoff_t pgoff, unsigned long nr_pages)
 {
 	unsigned long address;
diff --git a/mm/ksm.c b/mm/ksm.c
index a2e2a521df0a..2bbb321f92ac 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1257,7 +1257,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct folio *folio,
 	if (WARN_ON_ONCE(folio_test_large(folio)))
 		return err;
 
-	pvmw.address = page_address_in_vma(&folio->page, vma);
+	pvmw.address = page_address_in_vma(folio, folio_page(folio, 0), vma);
 	if (pvmw.address == -EFAULT)
 		goto out;
 
@@ -1341,7 +1341,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
 {
 	struct folio *kfolio = page_folio(kpage);
 	struct mm_struct *mm = vma->vm_mm;
-	struct folio *folio;
+	struct folio *folio = page_folio(page);
 	pmd_t *pmd;
 	pmd_t pmde;
 	pte_t *ptep;
@@ -1351,7 +1351,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
 	int err = -EFAULT;
 	struct mmu_notifier_range range;
 
-	addr = page_address_in_vma(page, vma);
+	addr = page_address_in_vma(folio, page, vma);
 	if (addr == -EFAULT)
 		goto out;
 
@@ -1417,7 +1417,6 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
 	ptep_clear_flush(vma, addr, ptep);
 	set_pte_at(mm, addr, ptep, newpte);
 
-	folio = page_folio(page);
 	folio_remove_rmap_pte(folio, page, vma);
 	if (!folio_mapped(folio))
 		folio_free_swap(folio);
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 58a3d80961a4..ea9d883c01c1 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -671,7 +671,7 @@ static void collect_procs_file(struct folio *folio, struct page *page,
 			 */
 			if (vma->vm_mm != t->mm)
 				continue;
-			addr = page_address_in_vma(page, vma);
+			addr = page_address_in_vma(folio, page, vma);
 			add_to_kill_anon_file(t, page, vma, to_kill, addr);
 		}
 	}
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index b646fab3e45e..b92113d27f63 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1367,7 +1367,7 @@ static long do_mbind(unsigned long start, unsigned long len,
 			if (!list_entry_is_head(folio, &pagelist, lru)) {
 				vma_iter_init(&vmi, mm, start);
 				for_each_vma_range(vmi, vma, end) {
-					addr = page_address_in_vma(
+					addr = page_address_in_vma(folio,
 						folio_page(folio, 0), vma);
 					if (addr != -EFAULT)
 						break;
diff --git a/mm/rmap.c b/mm/rmap.c
index 90df71c640bf..a7b4f9ba9a14 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -768,14 +768,27 @@ static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags)
 }
 #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
 
-/*
- * At what user virtual address is page expected in vma?
- * Caller should check the page is actually part of the vma.
+/**
+ * page_address_in_vma - The virtual address of a page in this VMA.
+ * @folio: The folio containing the page.
+ * @page: The page within the folio.
+ * @vma: The VMA we need to know the address in.
+ *
+ * Calculates the user virtual address of this page in the specified VMA.
+ * It is the caller's responsibililty to check the page is actually
+ * within the VMA.  There may not currently be a PTE pointing at this
+ * page, but if a page fault occurs at this address, this is the page
+ * which will be accessed.
+ *
+ * Context: Caller should hold a reference to the folio.  Caller should
+ * hold a lock (eg the i_mmap_lock or the mmap_lock) which keeps the
+ * VMA from being altered.
+ *
+ * Return: The virtual address corresponding to this page in the VMA.
  */
-unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
+unsigned long page_address_in_vma(const struct folio *folio,
+		const struct page *page, const struct vm_area_struct *vma)
 {
-	struct folio *folio = page_folio(page);
-
 	if (folio_test_anon(folio)) {
 		struct anon_vma *page__anon_vma = folio_anon_vma(folio);
 		/*
@@ -791,7 +804,7 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 		return -EFAULT;
 	}
 
-	/* The !page__anon_vma above handles KSM folios */
+	/* KSM folios don't reach here because of the !page__anon_vma check */
 	return vma_address(vma, page_pgoff(folio, page), 1);
 }
 
diff --git a/mm/util.c b/mm/util.c
index 4f1275023eb7..60017d2a9e48 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -820,7 +820,7 @@ void *vcalloc_noprof(size_t n, size_t size)
 }
 EXPORT_SYMBOL(vcalloc_noprof);
 
-struct anon_vma *folio_anon_vma(struct folio *folio)
+struct anon_vma *folio_anon_vma(const struct folio *folio)
 {
 	unsigned long mapping = (unsigned long)folio->mapping;
 
-- 
2.43.0

[PATCH v2 4/7] mm: Mass constification of folio/page pointers

[Matthew Wilcox (Oracle)]

Now that page_pgoff() takes const pointers, we can constify the
pointers to a lot of functions.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/ksm.h  |  7 ++++---
 include/linux/rmap.h | 10 +++++-----
 mm/internal.h        |  5 +++--
 mm/ksm.c             |  5 +++--
 mm/memory-failure.c  | 24 +++++++++++++-----------
 mm/page_vma_mapped.c |  5 +++--
 mm/rmap.c            | 11 ++++++-----
 7 files changed, 37 insertions(+), 30 deletions(-)

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 11690dacd986..c4a8891f6e7d 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -92,7 +92,7 @@ struct folio *ksm_might_need_to_copy(struct folio *folio,
 
 void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc);
 void folio_migrate_ksm(struct folio *newfolio, struct folio *folio);
-void collect_procs_ksm(struct folio *folio, struct page *page,
+void collect_procs_ksm(const struct folio *folio, const struct page *page,
 		struct list_head *to_kill, int force_early);
 long ksm_process_profit(struct mm_struct *);
 
@@ -125,8 +125,9 @@ static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte)
 {
 }
 
-static inline void collect_procs_ksm(struct folio *folio, struct page *page,
-				     struct list_head *to_kill, int force_early)
+static inline void collect_procs_ksm(const struct folio *folio,
+		const struct page *page, struct list_head *to_kill,
+		int force_early)
 {
 }
 
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 78923015a2e8..683a04088f3f 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -171,7 +171,7 @@ static inline void anon_vma_merge(struct vm_area_struct *vma,
 	unlink_anon_vmas(next);
 }
 
-struct anon_vma *folio_get_anon_vma(struct folio *folio);
+struct anon_vma *folio_get_anon_vma(const struct folio *folio);
 
 /* RMAP flags, currently only relevant for some anon rmap operations. */
 typedef int __bitwise rmap_t;
@@ -194,8 +194,8 @@ enum rmap_level {
 	RMAP_LEVEL_PMD,
 };
 
-static inline void __folio_rmap_sanity_checks(struct folio *folio,
-		struct page *page, int nr_pages, enum rmap_level level)
+static inline void __folio_rmap_sanity_checks(const struct folio *folio,
+		const struct page *page, int nr_pages, enum rmap_level level)
 {
 	/* hugetlb folios are handled separately. */
 	VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
@@ -771,14 +771,14 @@ struct rmap_walk_control {
 	bool (*rmap_one)(struct folio *folio, struct vm_area_struct *vma,
 					unsigned long addr, void *arg);
 	int (*done)(struct folio *folio);
-	struct anon_vma *(*anon_lock)(struct folio *folio,
+	struct anon_vma *(*anon_lock)(const struct folio *folio,
 				      struct rmap_walk_control *rwc);
 	bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
 };
 
 void rmap_walk(struct folio *folio, struct rmap_walk_control *rwc);
 void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc);
-struct anon_vma *folio_lock_anon_vma_read(struct folio *folio,
+struct anon_vma *folio_lock_anon_vma_read(const struct folio *folio,
 					  struct rmap_walk_control *rwc);
 
 #else	/* !CONFIG_MMU */
diff --git a/mm/internal.h b/mm/internal.h
index fffa9df41495..71a30e779223 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1072,10 +1072,11 @@ void ClearPageHWPoisonTakenOff(struct page *page);
 bool take_page_off_buddy(struct page *page);
 bool put_page_back_buddy(struct page *page);
 struct task_struct *task_early_kill(struct task_struct *tsk, int force_early);
-void add_to_kill_ksm(struct task_struct *tsk, struct page *p,
+void add_to_kill_ksm(struct task_struct *tsk, const struct page *p,
 		     struct vm_area_struct *vma, struct list_head *to_kill,
 		     unsigned long ksm_addr);
-unsigned long page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
+unsigned long page_mapped_in_vma(const struct page *page,
+		struct vm_area_struct *vma);
 
 #else
 static inline void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu)
diff --git a/mm/ksm.c b/mm/ksm.c
index 2bbb321f92ac..1fed2e3e01e0 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1052,7 +1052,8 @@ static int unmerge_ksm_pages(struct vm_area_struct *vma,
 	return err;
 }
 
-static inline struct ksm_stable_node *folio_stable_node(struct folio *folio)
+static inline
+struct ksm_stable_node *folio_stable_node(const struct folio *folio)
 {
 	return folio_test_ksm(folio) ? folio_raw_mapping(folio) : NULL;
 }
@@ -3066,7 +3067,7 @@ void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc)
 /*
  * Collect processes when the error hit an ksm page.
  */
-void collect_procs_ksm(struct folio *folio, struct page *page,
+void collect_procs_ksm(const struct folio *folio, const struct page *page,
 		struct list_head *to_kill, int force_early)
 {
 	struct ksm_stable_node *stable_node;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ea9d883c01c1..7ce7ba8586f5 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -445,7 +445,7 @@ static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma,
  * Schedule a process for later kill.
  * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
  */
-static void __add_to_kill(struct task_struct *tsk, struct page *p,
+static void __add_to_kill(struct task_struct *tsk, const struct page *p,
 			  struct vm_area_struct *vma, struct list_head *to_kill,
 			  unsigned long addr)
 {
@@ -461,7 +461,7 @@ static void __add_to_kill(struct task_struct *tsk, struct page *p,
 	if (is_zone_device_page(p))
 		tk->size_shift = dev_pagemap_mapping_shift(vma, tk->addr);
 	else
-		tk->size_shift = page_shift(compound_head(p));
+		tk->size_shift = folio_shift(page_folio(p));
 
 	/*
 	 * Send SIGKILL if "tk->addr == -EFAULT". Also, as
@@ -486,7 +486,7 @@ static void __add_to_kill(struct task_struct *tsk, struct page *p,
 	list_add_tail(&tk->nd, to_kill);
 }
 
-static void add_to_kill_anon_file(struct task_struct *tsk, struct page *p,
+static void add_to_kill_anon_file(struct task_struct *tsk, const struct page *p,
 		struct vm_area_struct *vma, struct list_head *to_kill,
 		unsigned long addr)
 {
@@ -509,7 +509,7 @@ static bool task_in_to_kill_list(struct list_head *to_kill,
 	return false;
 }
 
-void add_to_kill_ksm(struct task_struct *tsk, struct page *p,
+void add_to_kill_ksm(struct task_struct *tsk, const struct page *p,
 		     struct vm_area_struct *vma, struct list_head *to_kill,
 		     unsigned long addr)
 {
@@ -606,8 +606,9 @@ struct task_struct *task_early_kill(struct task_struct *tsk, int force_early)
 /*
  * Collect processes when the error hit an anonymous page.
  */
-static void collect_procs_anon(struct folio *folio, struct page *page,
-		struct list_head *to_kill, int force_early)
+static void collect_procs_anon(const struct folio *folio,
+		const struct page *page, struct list_head *to_kill,
+		int force_early)
 {
 	struct task_struct *tsk;
 	struct anon_vma *av;
@@ -643,8 +644,9 @@ static void collect_procs_anon(struct folio *folio, struct page *page,
 /*
  * Collect processes when the error hit a file mapped page.
  */
-static void collect_procs_file(struct folio *folio, struct page *page,
-		struct list_head *to_kill, int force_early)
+static void collect_procs_file(const struct folio *folio,
+		const struct page *page, struct list_head *to_kill,
+		int force_early)
 {
 	struct vm_area_struct *vma;
 	struct task_struct *tsk;
@@ -680,7 +682,7 @@ static void collect_procs_file(struct folio *folio, struct page *page,
 }
 
 #ifdef CONFIG_FS_DAX
-static void add_to_kill_fsdax(struct task_struct *tsk, struct page *p,
+static void add_to_kill_fsdax(struct task_struct *tsk, const struct page *p,
 			      struct vm_area_struct *vma,
 			      struct list_head *to_kill, pgoff_t pgoff)
 {
@@ -691,7 +693,7 @@ static void add_to_kill_fsdax(struct task_struct *tsk, struct page *p,
 /*
  * Collect processes when the error hit a fsdax page.
  */
-static void collect_procs_fsdax(struct page *page,
+static void collect_procs_fsdax(const struct page *page,
 		struct address_space *mapping, pgoff_t pgoff,
 		struct list_head *to_kill, bool pre_remove)
 {
@@ -725,7 +727,7 @@ static void collect_procs_fsdax(struct page *page,
 /*
  * Collect the processes who have the corrupted page mapped to kill.
  */
-static void collect_procs(struct folio *folio, struct page *page,
+static void collect_procs(const struct folio *folio, const struct page *page,
 		struct list_head *tokill, int force_early)
 {
 	if (!folio->mapping)
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index ade3c6833587..82e20dbbedb7 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -325,9 +325,10 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
  * outside the VMA or not present, returns -EFAULT.
  * Only valid for normal file or anonymous VMAs.
  */
-unsigned long page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
+unsigned long page_mapped_in_vma(const struct page *page,
+		struct vm_area_struct *vma)
 {
-	struct folio *folio = page_folio(page);
+	const struct folio *folio = page_folio(page);
 	struct page_vma_mapped_walk pvmw = {
 		.pfn = page_to_pfn(page),
 		.nr_pages = 1,
diff --git a/mm/rmap.c b/mm/rmap.c
index a7b4f9ba9a14..2c561b1e52cc 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -497,7 +497,7 @@ void __init anon_vma_init(void)
  * concurrently without folio lock protection). See folio_lock_anon_vma_read()
  * which has already covered that, and comment above remap_pages().
  */
-struct anon_vma *folio_get_anon_vma(struct folio *folio)
+struct anon_vma *folio_get_anon_vma(const struct folio *folio)
 {
 	struct anon_vma *anon_vma = NULL;
 	unsigned long anon_mapping;
@@ -541,7 +541,7 @@ struct anon_vma *folio_get_anon_vma(struct folio *folio)
  * reference like with folio_get_anon_vma() and then block on the mutex
  * on !rwc->try_lock case.
  */
-struct anon_vma *folio_lock_anon_vma_read(struct folio *folio,
+struct anon_vma *folio_lock_anon_vma_read(const struct folio *folio,
 					  struct rmap_walk_control *rwc)
 {
 	struct anon_vma *anon_vma = NULL;
@@ -1275,8 +1275,9 @@ static void __folio_set_anon(struct folio *folio, struct vm_area_struct *vma,
  * @vma:	the vm area in which the mapping is added
  * @address:	the user virtual address mapped
  */
-static void __page_check_anon_rmap(struct folio *folio, struct page *page,
-	struct vm_area_struct *vma, unsigned long address)
+static void __page_check_anon_rmap(const struct folio *folio,
+		const struct page *page, struct vm_area_struct *vma,
+		unsigned long address)
 {
 	/*
 	 * The page's anon-rmap details (mapping and index) are guaranteed to
@@ -2573,7 +2574,7 @@ void __put_anon_vma(struct anon_vma *anon_vma)
 		anon_vma_free(root);
 }
 
-static struct anon_vma *rmap_walk_anon_lock(struct folio *folio,
+static struct anon_vma *rmap_walk_anon_lock(const struct folio *folio,
 					    struct rmap_walk_control *rwc)
 {
 	struct anon_vma *anon_vma;
-- 
2.43.0

[PATCH v2 5/7] bootmem: Stop using page->index

[Matthew Wilcox (Oracle)]

Encode the type into the bottom four bits of page->private and the
info into the remaining bits.  Also turn the bootmem type into a
named enum.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 arch/x86/mm/init_64.c        |  9 ++++-----
 include/linux/bootmem_info.h | 25 +++++++++++++++++--------
 mm/bootmem_info.c            | 11 ++++++-----
 mm/sparse.c                  |  8 ++++----
 4 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ff253648706f..4d5fde324136 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -987,13 +987,12 @@ int arch_add_memory(int nid, u64 start, u64 size,
 
 static void __meminit free_pagetable(struct page *page, int order)
 {
-	unsigned long magic;
-	unsigned int nr_pages = 1 << order;
-
 	/* bootmem page has reserved flag */
 	if (PageReserved(page)) {
-		magic = page->index;
-		if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) {
+		enum bootmem_type type = bootmem_type(page);
+		unsigned long nr_pages = 1 << order;
+
+		if (type == SECTION_INFO || type == MIX_SECTION_INFO) {
 			while (nr_pages--)
 				put_page_bootmem(page++);
 		} else
diff --git a/include/linux/bootmem_info.h b/include/linux/bootmem_info.h
index cffa38a73618..e2fe5de93dcc 100644
--- a/include/linux/bootmem_info.h
+++ b/include/linux/bootmem_info.h
@@ -6,11 +6,10 @@
 #include <linux/kmemleak.h>
 
 /*
- * Types for free bootmem stored in page->lru.next. These have to be in
- * some random range in unsigned long space for debugging purposes.
+ * Types for free bootmem stored in the low bits of page->private.
  */
-enum {
-	MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE = 12,
+enum bootmem_type {
+	MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE = 1,
 	SECTION_INFO = MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE,
 	MIX_SECTION_INFO,
 	NODE_INFO,
@@ -21,9 +20,19 @@ enum {
 void __init register_page_bootmem_info_node(struct pglist_data *pgdat);
 
 void get_page_bootmem(unsigned long info, struct page *page,
-		      unsigned long type);
+		enum bootmem_type type);
 void put_page_bootmem(struct page *page);
 
+static inline enum bootmem_type bootmem_type(const struct page *page)
+{
+	return (unsigned long)page->private & 0xf;
+}
+
+static inline unsigned long bootmem_info(const struct page *page)
+{
+	return (unsigned long)page->private >> 4;
+}
+
 /*
  * Any memory allocated via the memblock allocator and not via the
  * buddy will be marked reserved already in the memmap. For those
@@ -31,7 +40,7 @@ void put_page_bootmem(struct page *page);
  */
 static inline void free_bootmem_page(struct page *page)
 {
-	unsigned long magic = page->index;
+	enum bootmem_type type = bootmem_type(page);
 
 	/*
 	 * The reserve_bootmem_region sets the reserved flag on bootmem
@@ -39,7 +48,7 @@ static inline void free_bootmem_page(struct page *page)
 	 */
 	VM_BUG_ON_PAGE(page_ref_count(page) != 2, page);
 
-	if (magic == SECTION_INFO || magic == MIX_SECTION_INFO)
+	if (type == SECTION_INFO || type == MIX_SECTION_INFO)
 		put_page_bootmem(page);
 	else
 		VM_BUG_ON_PAGE(1, page);
@@ -54,7 +63,7 @@ static inline void put_page_bootmem(struct page *page)
 }
 
 static inline void get_page_bootmem(unsigned long info, struct page *page,
-				    unsigned long type)
+				    enum bootmem_type type)
 {
 }
 
diff --git a/mm/bootmem_info.c b/mm/bootmem_info.c
index fa7cb0c87c03..95f288169a38 100644
--- a/mm/bootmem_info.c
+++ b/mm/bootmem_info.c
@@ -14,23 +14,24 @@
 #include <linux/memory_hotplug.h>
 #include <linux/kmemleak.h>
 
-void get_page_bootmem(unsigned long info, struct page *page, unsigned long type)
+void get_page_bootmem(unsigned long info, struct page *page,
+		enum bootmem_type type)
 {
-	page->index = type;
+	BUG_ON(type > 0xf);
+	BUG_ON(info > (ULONG_MAX >> 4));
 	SetPagePrivate(page);
-	set_page_private(page, info);
+	set_page_private(page, info << 4 | type);
 	page_ref_inc(page);
 }
 
 void put_page_bootmem(struct page *page)
 {
-	unsigned long type = page->index;
+	enum bootmem_type type = bootmem_type(page);
 
 	BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
 	       type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
 
 	if (page_ref_dec_return(page) == 1) {
-		page->index = 0;
 		ClearPagePrivate(page);
 		set_page_private(page, 0);
 		INIT_LIST_HEAD(&page->lru);
diff --git a/mm/sparse.c b/mm/sparse.c
index dc38539f8560..6ba5354cf2e1 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -720,19 +720,19 @@ static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
 static void free_map_bootmem(struct page *memmap)
 {
 	unsigned long maps_section_nr, removing_section_nr, i;
-	unsigned long magic, nr_pages;
+	unsigned long type, nr_pages;
 	struct page *page = virt_to_page(memmap);
 
 	nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 		>> PAGE_SHIFT;
 
 	for (i = 0; i < nr_pages; i++, page++) {
-		magic = page->index;
+		type = bootmem_type(page);
 
-		BUG_ON(magic == NODE_INFO);
+		BUG_ON(type == NODE_INFO);
 
 		maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
-		removing_section_nr = page_private(page);
+		removing_section_nr = bootmem_info(page);
 
 		/*
 		 * When this function is called, the removing section is
-- 
2.43.0

[PATCH v2 6/7] mm: Remove references to page->index in huge_memory.c

[Matthew Wilcox (Oracle)]

We already have folios in all these places; it's just a matter of
using them instead of the pages.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/huge_memory.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 3ca89e0279a7..812287dd6221 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3135,8 +3135,8 @@ static void __split_huge_page_tail(struct folio *folio, int tail,
 	/* ->mapping in first and second tail page is replaced by other uses */
 	VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING,
 			page_tail);
-	page_tail->mapping = head->mapping;
-	page_tail->index = head->index + tail;
+	new_folio->mapping = folio->mapping;
+	new_folio->index = folio->index + tail;
 
 	/*
 	 * page->private should not be set in tail pages. Fix up and warn once
@@ -3212,11 +3212,11 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	ClearPageHasHWPoisoned(head);
 
 	for (i = nr - new_nr; i >= new_nr; i -= new_nr) {
+		struct folio *tail;
 		__split_huge_page_tail(folio, i, lruvec, list, new_order);
+		tail = page_folio(head + i);
 		/* Some pages can be beyond EOF: drop them from page cache */
-		if (head[i].index >= end) {
-			struct folio *tail = page_folio(head + i);
-
+		if (tail->index >= end) {
 			if (shmem_mapping(folio->mapping))
 				nr_dropped++;
 			else if (folio_test_clear_dirty(tail))
@@ -3224,12 +3224,12 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 					inode_to_wb(folio->mapping->host));
 			__filemap_remove_folio(tail, NULL);
 			folio_put(tail);
-		} else if (!PageAnon(page)) {
-			__xa_store(&folio->mapping->i_pages, head[i].index,
-					head + i, 0);
+		} else if (!folio_test_anon(folio)) {
+			__xa_store(&folio->mapping->i_pages, tail->index,
+					tail, 0);
 		} else if (swap_cache) {
 			__xa_store(&swap_cache->i_pages, offset + i,
-					head + i, 0);
+					tail, 0);
 		}
 	}
 
-- 
2.43.0

[PATCH v2 7/7] mm: Use page->private instead of page->index in percpu

[Matthew Wilcox (Oracle)]

The percpu allocator only uses one field in struct page, just change
it from page->index to page->private.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/percpu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index da21680ff294..0d3e6b76e873 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -253,13 +253,13 @@ static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
 /* set the pointer to a chunk in a page struct */
 static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
 {
-	page->index = (unsigned long)pcpu;
+	page->private = (unsigned long)pcpu;
 }
 
 /* obtain pointer to a chunk from a page struct */
 static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
 {
-	return (struct pcpu_chunk *)page->index;
+	return (struct pcpu_chunk *)page->private;
 }
 
 static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
-- 
2.43.0

Re: [PATCH v2 5/7] bootmem: Stop using page->index

[kernel test robot]

Hi Matthew,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on tip/locking/core tip/x86/mm dennis-percpu/for-next linus/master v6.12-rc2 next-20241008]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/mm-Convert-page_to_pgoff-to-page_pgoff/20241006-040239
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20241005200121.3231142-6-willy%40infradead.org
patch subject: [PATCH v2 5/7] bootmem: Stop using page->index
config: x86_64-randconfig-011-20241008 (https://download.01.org/0day-ci/archive/20241009/202410090224.gxQY18rm-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241009/202410090224.gxQY18rm-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410090224.gxQY18rm-lkp@intel.com/

All errors (new ones prefixed by >>):

   arch/x86/mm/init_64.c: In function 'free_pagetable':
>> arch/x86/mm/init_64.c:992:42: error: implicit declaration of function 'bootmem_type' [-Werror=implicit-function-declaration]
     992 |                 enum bootmem_type type = bootmem_type(page);
         |                                          ^~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/bootmem_type +992 arch/x86/mm/init_64.c

   987	
   988	static void __meminit free_pagetable(struct page *page, int order)
   989	{
   990		/* bootmem page has reserved flag */
   991		if (PageReserved(page)) {
 > 992			enum bootmem_type type = bootmem_type(page);
   993			unsigned long nr_pages = 1 << order;
   994	
   995			if (type == SECTION_INFO || type == MIX_SECTION_INFO) {
   996				while (nr_pages--)
   997					put_page_bootmem(page++);
   998			} else
   999				while (nr_pages--)
  1000					free_reserved_page(page++);
  1001		} else
  1002			free_pages((unsigned long)page_address(page), order);
  1003	}
  1004	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v2 5/7] bootmem: Stop using page->index

[kernel test robot]

Hi Matthew,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on tip/locking/core tip/x86/mm dennis-percpu/for-next linus/master v6.12-rc2 next-20241008]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/mm-Convert-page_to_pgoff-to-page_pgoff/20241006-040239
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20241005200121.3231142-6-willy%40infradead.org
patch subject: [PATCH v2 5/7] bootmem: Stop using page->index
config: x86_64-randconfig-014-20241008 (https://download.01.org/0day-ci/archive/20241009/202410090311.eaqcL7IZ-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241009/202410090311.eaqcL7IZ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410090311.eaqcL7IZ-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/x86/mm/init_64.c:992:28: error: call to undeclared function 'bootmem_type'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     992 |                 enum bootmem_type type = bootmem_type(page);
         |                                          ^
   1 error generated.


vim +/bootmem_type +992 arch/x86/mm/init_64.c

   987	
   988	static void __meminit free_pagetable(struct page *page, int order)
   989	{
   990		/* bootmem page has reserved flag */
   991		if (PageReserved(page)) {
 > 992			enum bootmem_type type = bootmem_type(page);
   993			unsigned long nr_pages = 1 << order;
   994	
   995			if (type == SECTION_INFO || type == MIX_SECTION_INFO) {
   996				while (nr_pages--)
   997					put_page_bootmem(page++);
   998			} else
   999				while (nr_pages--)
  1000					free_reserved_page(page++);
  1001		} else
  1002			free_pages((unsigned long)page_address(page), order);
  1003	}
  1004	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v2 5/7] bootmem: Stop using page->index

[Andrew Morton]

On Wed, 9 Oct 2024 03:29:37 +0800 kernel test robot <lkp@intel.com> wrote:

> Hi Matthew,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on akpm-mm/mm-everything]
> [also build test ERROR on tip/locking/core tip/x86/mm dennis-percpu/for-next linus/master v6.12-rc2 next-20241008]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/mm-Convert-page_to_pgoff-to-page_pgoff/20241006-040239
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20241005200121.3231142-6-willy%40infradead.org
> patch subject: [PATCH v2 5/7] bootmem: Stop using page->index
> config: x86_64-randconfig-014-20241008 (https://download.01.org/0day-ci/archive/20241009/202410090311.eaqcL7IZ-lkp@intel.com/config)
> compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241009/202410090311.eaqcL7IZ-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202410090311.eaqcL7IZ-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
> >> arch/x86/mm/init_64.c:992:28: error: call to undeclared function 'bootmem_type'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>      992 |                 enum bootmem_type type = bootmem_type(page);
>          |                                          ^
>    1 error generated.
> 

Thanks, I did the below.  

I do wonder whether we should be using free_bootmem_page() in the
CONFIG_HAVE_BOOTMEM_INFO_NODE=n case,

And in the CONFIG_HAVE_BOOTMEM_INFO_NODE=y case, the logic in
free_pagetable() looks quite duplicative of the logic in
free_bootmem_page() (which seems too large to be inlined).

My new free_reserved_pages() should be moved elsewhere so riscv and
powerpc (at least) can use it.



From: Andrew Morton <akpm@linux-foundation.org>
Subject: bootmem-stop-using-page-index-fix
Date: Wed Oct  9 02:16:16 PM PDT 2024

fix arch/x86/mm/init_64.c build with !CONFIG_HAVE_BOOTMEM_INFO_NODE

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410090311.eaqcL7IZ-lkp@intel.com/
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/mm/init_64.c |   21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

--- a/arch/x86/mm/init_64.c~bootmem-stop-using-page-index-fix
+++ a/arch/x86/mm/init_64.c
@@ -985,21 +985,32 @@ int arch_add_memory(int nid, u64 start,
 	return add_pages(nid, start_pfn, nr_pages, params);
 }
 
+static void free_reserved_pages(struct page *page, unsigned long nr_pages)
+{
+	while (nr_pages--)
+		free_reserved_page(page++);
+}
+
 static void __meminit free_pagetable(struct page *page, int order)
 {
 	/* bootmem page has reserved flag */
 	if (PageReserved(page)) {
-		enum bootmem_type type = bootmem_type(page);
 		unsigned long nr_pages = 1 << order;
+#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
+		enum bootmem_type type = bootmem_type(page);
 
 		if (type == SECTION_INFO || type == MIX_SECTION_INFO) {
 			while (nr_pages--)
 				put_page_bootmem(page++);
-		} else
-			while (nr_pages--)
-				free_reserved_page(page++);
-	} else
+		} else {
+			free_reserved_pages(page, nr_pages);
+		}
+#else
+		free_reserved_pages(page, nr_pages);
+#endif
+	} else {
 		free_pages((unsigned long)page_address(page), order);
+	}
 }
 
 static void __meminit free_hugepage_table(struct page *page,
_