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 117b807e3f89..2f32eaccf0b9 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1089,6 +1089,15 @@ 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 @@ -1097,12 +1106,17 @@ 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 100f54fc9e6c..c0c6de31a313 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4314,7 +4314,8 @@ 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