The patch titled Subject: mm: add default definition of set_ptes() has been added to the -mm mm-unstable branch. Its filename is mm-add-default-definition-of-set_ptes.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-add-default-definition-of-set_ptes.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: mm: add default definition of set_ptes() Date: Wed, 2 Aug 2023 16:13:34 +0100 Most architectures can just define set_pte() and PFN_PTE_SHIFT to use this definition. It's also a handy spot to document the guarantees provided by the MM. Link: https://lkml.kernel.org/r/20230802151406.3735276-7-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Suggested-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx> Reviewed-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/pgtable.h | 81 ++++++++++++++++++++++++++++---------- 1 file changed, 60 insertions(+), 21 deletions(-) --- a/include/linux/pgtable.h~mm-add-default-definition-of-set_ptes +++ a/include/linux/pgtable.h @@ -182,6 +182,66 @@ static inline int pmd_young(pmd_t pmd) } #endif +/* + * A facility to provide lazy MMU batching. This allows PTE updates and + * page invalidations to be delayed until a call to leave lazy MMU mode + * is issued. Some architectures may benefit from doing this, and it is + * beneficial for both shadow and direct mode hypervisors, which may batch + * the PTE updates which happen during this window. Note that using this + * interface requires that read hazards be removed from the code. A read + * hazard could result in the direct mode hypervisor case, since the actual + * write to the page tables may not yet have taken place, so reads though + * a raw PTE pointer after it has been modified are not guaranteed to be + * up to date. This mode can only be entered and left under the protection of + * the page table locks for all page tables which may be modified. In the UP + * case, this is required so that preemption is disabled, and in the SMP case, + * it must synchronize the delayed page table writes properly on other CPUs. + */ +#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE +#define arch_enter_lazy_mmu_mode() do {} while (0) +#define arch_leave_lazy_mmu_mode() do {} while (0) +#define arch_flush_lazy_mmu_mode() do {} while (0) +#endif + +#ifndef set_ptes +#ifdef PFN_PTE_SHIFT +/** + * set_ptes - Map consecutive pages to a contiguous range of addresses. + * @mm: Address space to map the pages into. + * @addr: Address to map the first page at. + * @ptep: Page table pointer for the first entry. + * @pte: Page table entry for the first page. + * @nr: Number of pages to map. + * + * May be overridden by the architecture, or the architecture can define + * set_pte() and PFN_PTE_SHIFT. + * + * Context: The caller holds the page table lock. The pages all belong + * to the same folio. The PTEs are all in the same PMD. + */ +static inline void set_ptes(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pte, unsigned int nr) +{ + page_table_check_ptes_set(mm, ptep, pte, nr); + + arch_enter_lazy_mmu_mode(); + for (;;) { + set_pte(ptep, pte); + if (--nr == 0) + break; + ptep++; + pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT)); + } + arch_leave_lazy_mmu_mode(); +} +#ifndef set_pte_at +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1) +#endif +#endif +#else +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1) +#endif + #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS extern int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address, pte_t *ptep, @@ -1132,27 +1192,6 @@ static inline pgprot_t pgprot_modify(pgp #endif /* - * A facility to provide lazy MMU batching. This allows PTE updates and - * page invalidations to be delayed until a call to leave lazy MMU mode - * is issued. Some architectures may benefit from doing this, and it is - * beneficial for both shadow and direct mode hypervisors, which may batch - * the PTE updates which happen during this window. Note that using this - * interface requires that read hazards be removed from the code. A read - * hazard could result in the direct mode hypervisor case, since the actual - * write to the page tables may not yet have taken place, so reads though - * a raw PTE pointer after it has been modified are not guaranteed to be - * up to date. This mode can only be entered and left under the protection of - * the page table locks for all page tables which may be modified. In the UP - * case, this is required so that preemption is disabled, and in the SMP case, - * it must synchronize the delayed page table writes properly on other CPUs. - */ -#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE -#define arch_enter_lazy_mmu_mode() do {} while (0) -#define arch_leave_lazy_mmu_mode() do {} while (0) -#define arch_flush_lazy_mmu_mode() do {} while (0) -#endif - -/* * A facility to provide batching of the reload of page tables and * other process state with the actual context switch code for * paravirtualized guests. By convention, only one of the batched _ Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are mm-drop-per-vma-lock-when-returning-vm_fault_retry-or-vm_fault_completed-fix.patch rmap-pass-the-folio-to-__page_check_anon_rmap.patch highmem-add-memcpy_to_folio-and-memcpy_from_folio.patch affs-convert-affs_symlink_read_folio-to-use-the-folio.patch affs-convert-data-read-and-write-to-use-folios.patch migrate-use-folio_set_bh-instead-of-set_bh_page.patch ntfs3-convert-ntfs_get_block_vbo-to-use-a-folio.patch jbd2-use-a-folio-in-jbd2_journal_write_metadata_buffer.patch buffer-remove-set_bh_page.patch zswap-make-zswap_store-take-a-folio.patch memcg-convert-get_obj_cgroup_from_page-to-get_obj_cgroup_from_folio.patch swap-remove-some-calls-to-compound_head-in-swap_readpage.patch zswap-make-zswap_load-take-a-folio.patch mm-remove-config_per_vma_lock-ifdefs.patch mm-allow-per-vma-locks-on-file-backed-vmas.patch mm-move-fault_flag_vma_lock-check-from-handle_mm_fault.patch mm-handle-pud-faults-under-the-vma-lock.patch mm-handle-some-pmd-faults-under-the-vma-lock.patch mm-move-fault_flag_vma_lock-check-down-in-handle_pte_fault.patch mm-move-fault_flag_vma_lock-check-down-from-do_fault.patch mm-run-the-fault-around-code-under-the-vma-lock.patch mm-handle-swap-and-numa-pte-faults-under-the-vma-lock.patch mm-handle-faults-that-merely-update-the-accessed-bit-under-the-vma-lock.patch mm-handle-faults-that-merely-update-the-accessed-bit-under-the-vma-lock-fix.patch mm-improve-the-comment-in-isolate_migratepages_block.patch minmax-add-in_range-macro.patch mm-convert-page_table_check_pte_set-to-page_table_check_ptes_set.patch mm-add-generic-flush_icache_pages-and-documentation.patch mm-add-folio_flush_mapping.patch mm-remove-arch_implements_flush_dcache_folio.patch mm-add-default-definition-of-set_ptes.patch alpha-implement-the-new-page-table-range-api.patch arc-implement-the-new-page-table-range-api.patch arm-implement-the-new-page-table-range-api.patch arm64-implement-the-new-page-table-range-api.patch csky-implement-the-new-page-table-range-api.patch hexagon-implement-the-new-page-table-range-api.patch ia64-implement-the-new-page-table-range-api.patch loongarch-implement-the-new-page-table-range-api.patch m68k-implement-the-new-page-table-range-api.patch microblaze-implement-the-new-page-table-range-api.patch mips-implement-the-new-page-table-range-api.patch nios2-implement-the-new-page-table-range-api.patch openrisc-implement-the-new-page-table-range-api.patch parisc-implement-the-new-page-table-range-api.patch powerpc-implement-the-new-page-table-range-api.patch riscv-implement-the-new-page-table-range-api.patch s390-implement-the-new-page-table-range-api.patch sh-implement-the-new-page-table-range-api.patch sparc32-implement-the-new-page-table-range-api.patch sparc64-implement-the-new-page-table-range-api.patch um-implement-the-new-page-table-range-api.patch x86-implement-the-new-page-table-range-api.patch xtensa-implement-the-new-page-table-range-api.patch mm-remove-page_mapping_file.patch mm-rationalise-flush_icache_pages-and-flush_icache_page.patch mm-tidy-up-set_ptes-definition.patch mm-use-flush_icache_pages-in-do_set_pmd.patch mm-call-update_mmu_cache_range-in-more-page-fault-handling-paths.patch