From: Barry Song <v-songbaohua@xxxxxxxx>
Should do_swap_page() have the capability to directly map a large folio,
metadata restoration becomes necessary for a specified number of pages
denoted as nr. It's important to highlight that metadata restoration is
solely required by the SPARC platform, which, however, does not enable
THP_SWAP. Consequently, in the present kernel configuration, there
exists no practical scenario where users necessitate the restoration of
nr metadata. Platforms implementing THP_SWAP might invoke this function
with nr values exceeding 1, subsequent to do_swap_page() successfully
mapping an entire large folio. Nonetheless, their arch_do_swap_page_nr()
functions remain empty.
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Reviewed-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Reviewed-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Andreas Larsson <andreas@xxxxxxxxxxx>
---
include/linux/pgtable.h | 26 ++++++++++++++++++++------
mm/memory.c | 3 ++-
2 files changed, 22 insertions(+), 7 deletions(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 18019f037bae..463e84c3de26 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1084,6 +1084,15 @@ static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)
})
#ifndef __HAVE_ARCH_DO_SWAP_PAGE
+static inline void arch_do_swap_page_nr(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t pte, pte_t oldpte,
+ int nr)
+{
+
+}
+#else
/*
* Some architectures support metadata associated with a page. When a
* page is being swapped out, this metadata must be saved so it can be
@@ -1092,12 +1101,17 @@ static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)
* page as metadata for the page. arch_do_swap_page() can restore this
* metadata when a page is swapped back in.
*/
-static inline void arch_do_swap_page(struct mm_struct *mm,
- struct vm_area_struct *vma,
- unsigned long addr,
- pte_t pte, pte_t oldpte)
-{
-
+static inline void arch_do_swap_page_nr(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t pte, pte_t oldpte,
+ int nr)
+{
+ for (int i = 0; i < nr; i++) {
+ arch_do_swap_page(vma->vm_mm, vma, addr + i * PAGE_SIZE,
+ pte_advance_pfn(pte, i),
+ pte_advance_pfn(oldpte, i));
+ }
}
#endif
diff --git a/mm/memory.c b/mm/memory.c
index eea6e4984eae..b51c059af0b0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4266,7 +4266,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
VM_BUG_ON(!folio_test_anon(folio) ||
(pte_write(pte) && !PageAnonExclusive(page)));
set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte);
- arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte);
+ arch_do_swap_page_nr(vma->vm_mm, vma, vmf->address,
+ pte, vmf->orig_pte, 1);
folio_unlock(folio);
if (folio != swapcache && swapcache) {
--
2.34.1
