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Message-ID: <87097d3d5ef1d46959d09cfc7e192c4551b87771.1746795452.git.baolin.wang@linux.alibaba.com>
Date: Fri, 9 May 2025 21:01:04 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: akpm@...ux-foundation.org,
willy@...radead.org,
david@...hat.com
Cc: hannes@...xchg.org,
lorenzo.stoakes@...cle.com,
Liam.Howlett@...cle.com,
npache@...hat.com,
ryan.roberts@....com,
dev.jain@....com,
ziy@...dia.com,
vbabka@...e.cz,
rppt@...nel.org,
surenb@...gle.com,
mhocko@...e.com,
baolin.wang@...ux.alibaba.com,
linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/2] mm: convert do_set_pmd() to take a folio
In do_set_pmd(), we always use the folio->page to build PMD mappings for
the entire folio. Since all callers of do_set_pmd() already hold a stable
folio, converting do_set_pmd() to take a folio is safe and more straightforward.
In addition, to ensure the extensibility of do_set_pmd() for supporting
larger folios beyond PMD size, we keep the 'page' parameter to specify
which page within the folio should be mapped.
No functional changes expected.
Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
---
Changes from v1:
- Keep the 'page' parameter of the do_set_pmd().
Note: I did mm selftests and built kernel on tmpfs/xfs filesystems, and
did not find any regression.
---
include/linux/mm.h | 2 +-
mm/filemap.c | 2 +-
mm/khugepaged.c | 2 +-
mm/memory.c | 11 +++++------
4 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 43748c8f3454..d5f578c91e77 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1237,7 +1237,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
return pte;
}
-vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page);
+vm_fault_t do_set_pmd(struct vm_fault *vmf, struct folio *folio, struct page *page);
void set_pte_range(struct vm_fault *vmf, struct folio *folio,
struct page *page, unsigned int nr, unsigned long addr);
diff --git a/mm/filemap.c b/mm/filemap.c
index 7b90cbeb4a1a..09d005848f0d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3533,7 +3533,7 @@ static bool filemap_map_pmd(struct vm_fault *vmf, struct folio *folio,
if (pmd_none(*vmf->pmd) && folio_test_pmd_mappable(folio)) {
struct page *page = folio_file_page(folio, start);
- vm_fault_t ret = do_set_pmd(vmf, page);
+ vm_fault_t ret = do_set_pmd(vmf, folio, page);
if (!ret) {
/* The page is mapped successfully, reference consumed. */
folio_unlock(folio);
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index aca66e7f4fd9..c4b5031f3254 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1478,7 +1478,7 @@ static int set_huge_pmd(struct vm_area_struct *vma, unsigned long addr,
mmap_assert_locked(vma->vm_mm);
- if (do_set_pmd(&vmf, &folio->page))
+ if (do_set_pmd(&vmf, folio, &folio->page))
return SCAN_FAIL;
folio_get(folio);
diff --git a/mm/memory.c b/mm/memory.c
index 68c1d962d0ad..9c202c32ca66 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5176,9 +5176,8 @@ static void deposit_prealloc_pte(struct vm_fault *vmf)
vmf->prealloc_pte = NULL;
}
-vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
+vm_fault_t do_set_pmd(struct vm_fault *vmf, struct folio *folio, struct page *page)
{
- struct folio *folio = page_folio(page);
struct vm_area_struct *vma = vmf->vma;
bool write = vmf->flags & FAULT_FLAG_WRITE;
unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
@@ -5251,7 +5250,7 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
return ret;
}
#else
-vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
+vm_fault_t do_set_pmd(struct vm_fault *vmf, struct folio *folio, struct page *page)
{
return VM_FAULT_FALLBACK;
}
@@ -5345,6 +5344,7 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
else
page = vmf->page;
+ folio = page_folio(page);
/*
* check even for read faults because we might have lost our CoWed
* page
@@ -5356,8 +5356,8 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
}
if (pmd_none(*vmf->pmd)) {
- if (PageTransCompound(page)) {
- ret = do_set_pmd(vmf, page);
+ if (folio_test_pmd_mappable(folio)) {
+ ret = do_set_pmd(vmf, folio, page);
if (ret != VM_FAULT_FALLBACK)
return ret;
}
@@ -5368,7 +5368,6 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
return VM_FAULT_OOM;
}
- folio = page_folio(page);
nr_pages = folio_nr_pages(folio);
/*
--
2.43.5
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