[PATCH v5 0/2] Generalize vmemmap_populate_hugepages to sparc

[PATCH v5 0/2] Generalize vmemmap_populate_hugepages to sparc

[chengkaitao]

Change sparc's implementation of vmemmap_populate() using
vmemmap_populate_hugepages() to streamline the code. Another
benefit is that it allows us to eliminate the external declarations
of vmemmap_p?d_populate functions and convert them to static functions.

Since vmemmap_populate_hugepages may fallback to vmemmap_populate-
_basepages, which differs from sparc's original implementation.
During the v1 discussion with Mike Rapoport, sparc uses base pages
in the kernel page tables, so it should be able to use them in
vmemmap as well. Consequently, no additional special handling is
required.

Remove unnecessary whitespace from sparc.

Changes in v5:
- remove [PATCH v4 3/3] sparc: Remove unnecessary whitespace

Changes in v4:
- Add commit message
- Add verification that pmd actually maps a large page in the
vmemmap_check_pmd function

Changes in v3:
- Allow sparc to fallback to vmemmap_populate_basepages
- Convert vmemmap_p?d_populate() to static functions
- Split the v1 patch

Changes in v2:
- Revert the whitespace deletions
- Change vmemmap_false_pmd to vmemmap_pte_fallback_allowed

Link to V4:
https://lore.kernel.org/all/20251219115812.65855-1-pilgrimtao@gmail.com/
Link to V3:
https://lore.kernel.org/all/20251218174749.45965-1-pilgrimtao@gmail.com/
Link to V2:
https://lore.kernel.org/all/20251218130957.36892-1-pilgrimtao@gmail.com/
Link to V1:
https://lore.kernel.org/all/20251217120858.18713-1-pilgrimtao@gmail.com/

Chengkaitao (2):
  sparc: Use vmemmap_populate_hugepages for vmemmap_populate
  mm: Convert vmemmap_p?d_populate() to static functions

 arch/sparc/mm/init_64.c | 47 ++++++++++++++---------------------------
 include/linux/mm.h      |  7 ------
 mm/sparse-vmemmap.c     | 10 ++++-----
 3 files changed, 21 insertions(+), 43 deletions(-)

-- 
2.50.1 (Apple Git-155)

[PATCH v5 1/2] sparc: Use vmemmap_populate_hugepages for vmemmap_populate

[chengkaitao]

From: Chengkaitao <chengkaitao@kylinos.cn>

1. In the SPARC architecture, reimplemented vmemmap_populate using
vmemmap_populate_hugepages.
2. Allow the SPARC arch to fallback to vmemmap_populate_basepages(),
when vmemmap_alloc_block returns NULL.

Signed-off-by: Chengkaitao <chengkaitao@kylinos.cn>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 arch/sparc/mm/init_64.c | 47 ++++++++++++++---------------------------
 1 file changed, 16 insertions(+), 31 deletions(-)

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index df9f7c444c39..858eaa6615ea 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2581,8 +2581,8 @@ unsigned long _PAGE_CACHE __read_mostly;
 EXPORT_SYMBOL(_PAGE_CACHE);
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
-int __meminit vmemmap_populate(unsigned long vstart, unsigned long vend,
-			       int node, struct vmem_altmap *altmap)
+void __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,
+			       unsigned long addr, unsigned long next)
 {
 	unsigned long pte_base;
 
@@ -2595,39 +2595,24 @@ int __meminit vmemmap_populate(unsigned long vstart, unsigned long vend,
 
 	pte_base |= _PAGE_PMD_HUGE;
 
-	vstart = vstart & PMD_MASK;
-	vend = ALIGN(vend, PMD_SIZE);
-	for (; vstart < vend; vstart += PMD_SIZE) {
-		pgd_t *pgd = vmemmap_pgd_populate(vstart, node);
-		unsigned long pte;
-		p4d_t *p4d;
-		pud_t *pud;
-		pmd_t *pmd;
-
-		if (!pgd)
-			return -ENOMEM;
-
-		p4d = vmemmap_p4d_populate(pgd, vstart, node);
-		if (!p4d)
-			return -ENOMEM;
-
-		pud = vmemmap_pud_populate(p4d, vstart, node);
-		if (!pud)
-			return -ENOMEM;
+	pmd_val(*pmd) = pte_base | __pa(p);
+}
 
-		pmd = pmd_offset(pud, vstart);
-		pte = pmd_val(*pmd);
-		if (!(pte & _PAGE_VALID)) {
-			void *block = vmemmap_alloc_block(PMD_SIZE, node);
+int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node,
+				unsigned long addr, unsigned long next)
+{
+	int large = pmd_leaf(*pmdp);
 
-			if (!block)
-				return -ENOMEM;
+	if (large)
+		vmemmap_verify((pte_t *)pmdp, node, addr, next);
 
-			pmd_val(*pmd) = pte_base | __pa(block);
-		}
-	}
+	return large;
+}
 
-	return 0;
+int __meminit vmemmap_populate(unsigned long vstart, unsigned long vend,
+			       int node, struct vmem_altmap *altmap)
+{
+	return vmemmap_populate_hugepages(vstart, vend, node, altmap);
 }
 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 
-- 
2.50.1 (Apple Git-155)

[PATCH v5 2/2] mm: Convert vmemmap_p?d_populate() to static functions

[chengkaitao]

From: Chengkaitao <chengkaitao@kylinos.cn>

Since the vmemmap_p?d_populate functions are unused outside the mm
subsystem, we can remove their external declarations and convert
them to static functions.

Signed-off-by: Chengkaitao <chengkaitao@kylinos.cn>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 include/linux/mm.h  |  7 -------
 mm/sparse-vmemmap.c | 10 +++++-----
 2 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6f959d8ca4b4..322fe72b6ebd 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4234,13 +4234,6 @@ unsigned long section_map_size(void);
 struct page * __populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
 		struct dev_pagemap *pgmap);
-pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
-p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
-pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);
-pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
-pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
-			    struct vmem_altmap *altmap, unsigned long ptpfn,
-			    unsigned long flags);
 void *vmemmap_alloc_block(unsigned long size, int node);
 struct vmem_altmap;
 void *vmemmap_alloc_block_buf(unsigned long size, int node,
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 37522d6cb398..67f9a08c2376 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -151,7 +151,7 @@ void __meminit vmemmap_verify(pte_t *pte, int node,
 			start, end - 1);
 }
 
-pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
+static pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
 				       struct vmem_altmap *altmap,
 				       unsigned long ptpfn, unsigned long flags)
 {
@@ -195,7 +195,7 @@ static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node)
 	return p;
 }
 
-pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
+static pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
 {
 	pmd_t *pmd = pmd_offset(pud, addr);
 	if (pmd_none(*pmd)) {
@@ -208,7 +208,7 @@ pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
 	return pmd;
 }
 
-pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
+static pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
 {
 	pud_t *pud = pud_offset(p4d, addr);
 	if (pud_none(*pud)) {
@@ -221,7 +221,7 @@ pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
 	return pud;
 }
 
-p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
+static p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
 {
 	p4d_t *p4d = p4d_offset(pgd, addr);
 	if (p4d_none(*p4d)) {
@@ -234,7 +234,7 @@ p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
 	return p4d;
 }
 
-pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
+static pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
 {
 	pgd_t *pgd = pgd_offset_k(addr);
 	if (pgd_none(*pgd)) {
-- 
2.50.1 (Apple Git-155)