Re: [PATCH v2] mm/hugetlb: add more arch-defined huge_pte functions

From: Michal Hocko
Date: Fri Mar 15 2013 - 12:02:57 EST

On Thu 14-03-13 18:51:03, Gerald Schaefer wrote:
> Commit abf09bed3c "s390/mm: implement software dirty bits" introduced
> another difference in the pte layout vs. the pmd layout on s390,
> thoroughly breaking the s390 support for hugetlbfs. This requires
> replacing some more pte_xxx functions in mm/hugetlbfs.c with a
> huge_pte_xxx version.
>
> This patch introduces those huge_pte_xxx functions and their
> generic implementation in asm-generic/hugetlb.h, which will now be
> included on all architectures supporting hugetlbfs apart from s390.
> This change will be a no-op for those architectures.
>
> Signed-off-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>

yes this looks much better. I cannot talk about s390 part because I am
not familiar with it but the rest looks good to me.

Maybe one nit, though. pte_page and pte_same do not have their huge_Foo
counterparts.

Anyway
Acked-by: Michal Hocko <mhocko@xxxxxxx> # for !s390 parts

Thanks!

> ---
> arch/ia64/include/asm/hugetlb.h | 1 +
> arch/mips/include/asm/hugetlb.h | 1 +
> arch/powerpc/include/asm/hugetlb.h | 1 +
> arch/s390/include/asm/hugetlb.h | 56 +++++++++++++++++++++-
> arch/s390/include/asm/pgtable.h | 95 ++++++++++++++++----------------------
> arch/s390/mm/hugetlbpage.c | 2 +-
> arch/sh/include/asm/hugetlb.h | 1 +
> arch/sparc/include/asm/hugetlb.h | 1 +
> arch/tile/include/asm/hugetlb.h | 1 +
> arch/x86/include/asm/hugetlb.h | 1 +
> include/asm-generic/hugetlb.h | 40 ++++++++++++++++
> mm/hugetlb.c | 23 ++++-----
> 12 files changed, 155 insertions(+), 68 deletions(-)
> create mode 100644 include/asm-generic/hugetlb.h
>
> diff --git a/arch/ia64/include/asm/hugetlb.h b/arch/ia64/include/asm/hugetlb.h
> index 94eaa5b..aa91005 100644
> --- a/arch/ia64/include/asm/hugetlb.h
> +++ b/arch/ia64/include/asm/hugetlb.h
> @@ -2,6 +2,7 @@
> #define _ASM_IA64_HUGETLB_H
>
> #include <asm/page.h>
> +#include <asm-generic/hugetlb.h>
>
>
> void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
> diff --git a/arch/mips/include/asm/hugetlb.h b/arch/mips/include/asm/hugetlb.h
> index ef99db9..fe0d15d 100644
> --- a/arch/mips/include/asm/hugetlb.h
> +++ b/arch/mips/include/asm/hugetlb.h
> @@ -10,6 +10,7 @@
> #define __ASM_HUGETLB_H
>
> #include <asm/page.h>
> +#include <asm-generic/hugetlb.h>
>
>
> static inline int is_hugepage_only_range(struct mm_struct *mm,
> diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
> index 62e11a3..4fcbd6b 100644
> --- a/arch/powerpc/include/asm/hugetlb.h
> +++ b/arch/powerpc/include/asm/hugetlb.h
> @@ -3,6 +3,7 @@
>
> #ifdef CONFIG_HUGETLB_PAGE
> #include <asm/page.h>
> +#include <asm-generic/hugetlb.h>
>
> extern struct kmem_cache *hugepte_cache;
>
> diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
> index 593753e..bd90359 100644
> --- a/arch/s390/include/asm/hugetlb.h
> +++ b/arch/s390/include/asm/hugetlb.h
> @@ -114,7 +114,7 @@ static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
> #define huge_ptep_set_wrprotect(__mm, __addr, __ptep) \
> ({ \
> pte_t __pte = huge_ptep_get(__ptep); \
> - if (pte_write(__pte)) { \
> + if (huge_pte_write(__pte)) { \
> huge_ptep_invalidate(__mm, __addr, __ptep); \
> set_huge_pte_at(__mm, __addr, __ptep, \
> huge_pte_wrprotect(__pte)); \
> @@ -127,4 +127,58 @@ static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
> huge_ptep_invalidate(vma->vm_mm, address, ptep);
> }
>
> +static inline pte_t mk_huge_pte(struct page *page, pgprot_t pgprot)
> +{
> + pte_t pte;
> + pmd_t pmd;
> +
> + pmd = mk_pmd_phys(page_to_phys(page), pgprot);
> + pte_val(pte) = pmd_val(pmd);
> + return pte;
> +}
> +
> +static inline int huge_pte_write(pte_t pte)
> +{
> + pmd_t pmd;
> +
> + pmd_val(pmd) = pte_val(pte);
> + return pmd_write(pmd);
> +}
> +
> +static inline int huge_pte_dirty(pte_t pte)
> +{
> + /* No dirty bit in the segment table entry. */
> + return 0;
> +}
> +
> +static inline pte_t huge_pte_mkwrite(pte_t pte)
> +{
> + pmd_t pmd;
> +
> + pmd_val(pmd) = pte_val(pte);
> + pte_val(pte) = pmd_val(pmd_mkwrite(pmd));
> + return pte;
> +}
> +
> +static inline pte_t huge_pte_mkdirty(pte_t pte)
> +{
> + /* No dirty bit in the segment table entry. */
> + return pte;
> +}
> +
> +static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot)
> +{
> + pmd_t pmd;
> +
> + pmd_val(pmd) = pte_val(pte);
> + pte_val(pte) = pmd_val(pmd_modify(pmd, newprot));
> + return pte;
> +}
> +
> +static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
> + pte_t *ptep)
> +{
> + pmd_clear((pmd_t *) ptep);
> +}
> +
> #endif /* _ASM_S390_HUGETLB_H */
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index 75b8750..7c9a145 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -419,6 +419,13 @@ extern unsigned long MODULES_END;
> #define __S110 PAGE_RW
> #define __S111 PAGE_RW
>
> +/*
> + * Segment entry (large page) protection definitions.
> + */
> +#define SEGMENT_NONE __pgprot(_HPAGE_TYPE_NONE)
> +#define SEGMENT_RO __pgprot(_HPAGE_TYPE_RO)
> +#define SEGMENT_RW __pgprot(_HPAGE_TYPE_RW)
> +
> static inline int mm_exclusive(struct mm_struct *mm)
> {
> return likely(mm == current->active_mm &&
> @@ -909,26 +916,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
> #ifdef CONFIG_HUGETLB_PAGE
> static inline pte_t pte_mkhuge(pte_t pte)
> {
> - /*
> - * PROT_NONE needs to be remapped from the pte type to the ste type.
> - * The HW invalid bit is also different for pte and ste. The pte
> - * invalid bit happens to be the same as the ste _SEGMENT_ENTRY_LARGE
> - * bit, so we don't have to clear it.
> - */
> - if (pte_val(pte) & _PAGE_INVALID) {
> - if (pte_val(pte) & _PAGE_SWT)
> - pte_val(pte) |= _HPAGE_TYPE_NONE;
> - pte_val(pte) |= _SEGMENT_ENTRY_INV;
> - }
> - /*
> - * Clear SW pte bits, there are no SW bits in a segment table entry.
> - */
> - pte_val(pte) &= ~(_PAGE_SWT | _PAGE_SWX | _PAGE_SWC |
> - _PAGE_SWR | _PAGE_SWW);
> - /*
> - * Also set the change-override bit because we don't need dirty bit
> - * tracking for hugetlbfs pages.
> - */
> pte_val(pte) |= (_SEGMENT_ENTRY_LARGE | _SEGMENT_ENTRY_CO);
> return pte;
> }
> @@ -1273,31 +1260,7 @@ static inline void __pmd_idte(unsigned long address, pmd_t *pmdp)
> }
> }
>
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> -
> -#define SEGMENT_NONE __pgprot(_HPAGE_TYPE_NONE)
> -#define SEGMENT_RO __pgprot(_HPAGE_TYPE_RO)
> -#define SEGMENT_RW __pgprot(_HPAGE_TYPE_RW)
> -
> -#define __HAVE_ARCH_PGTABLE_DEPOSIT
> -extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable);
> -
> -#define __HAVE_ARCH_PGTABLE_WITHDRAW
> -extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm);
> -
> -static inline int pmd_trans_splitting(pmd_t pmd)
> -{
> - return pmd_val(pmd) & _SEGMENT_ENTRY_SPLIT;
> -}
> -
> -static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
> - pmd_t *pmdp, pmd_t entry)
> -{
> - if (!(pmd_val(entry) & _SEGMENT_ENTRY_INV) && MACHINE_HAS_EDAT1)
> - pmd_val(entry) |= _SEGMENT_ENTRY_CO;
> - *pmdp = entry;
> -}
> -
> +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE)
> static inline unsigned long massage_pgprot_pmd(pgprot_t pgprot)
> {
> /*
> @@ -1318,10 +1281,11 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
> return pmd;
> }
>
> -static inline pmd_t pmd_mkhuge(pmd_t pmd)
> +static inline pmd_t mk_pmd_phys(unsigned long physpage, pgprot_t pgprot)
> {
> - pmd_val(pmd) |= _SEGMENT_ENTRY_LARGE;
> - return pmd;
> + pmd_t __pmd;
> + pmd_val(__pmd) = physpage + massage_pgprot_pmd(pgprot);
> + return __pmd;
> }
>
> static inline pmd_t pmd_mkwrite(pmd_t pmd)
> @@ -1331,6 +1295,34 @@ static inline pmd_t pmd_mkwrite(pmd_t pmd)
> pmd_val(pmd) &= ~_SEGMENT_ENTRY_RO;
> return pmd;
> }
> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLB_PAGE */
> +
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +
> +#define __HAVE_ARCH_PGTABLE_DEPOSIT
> +extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable);
> +
> +#define __HAVE_ARCH_PGTABLE_WITHDRAW
> +extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm);
> +
> +static inline int pmd_trans_splitting(pmd_t pmd)
> +{
> + return pmd_val(pmd) & _SEGMENT_ENTRY_SPLIT;
> +}
> +
> +static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
> + pmd_t *pmdp, pmd_t entry)
> +{
> + if (!(pmd_val(entry) & _SEGMENT_ENTRY_INV) && MACHINE_HAS_EDAT1)
> + pmd_val(entry) |= _SEGMENT_ENTRY_CO;
> + *pmdp = entry;
> +}
> +
> +static inline pmd_t pmd_mkhuge(pmd_t pmd)
> +{
> + pmd_val(pmd) |= _SEGMENT_ENTRY_LARGE;
> + return pmd;
> +}
>
> static inline pmd_t pmd_wrprotect(pmd_t pmd)
> {
> @@ -1427,13 +1419,6 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
> }
> }
>
> -static inline pmd_t mk_pmd_phys(unsigned long physpage, pgprot_t pgprot)
> -{
> - pmd_t __pmd;
> - pmd_val(__pmd) = physpage + massage_pgprot_pmd(pgprot);
> - return __pmd;
> -}
> -
> #define pfn_pmd(pfn, pgprot) mk_pmd_phys(__pa((pfn) << PAGE_SHIFT), (pgprot))
> #define mk_pmd(page, pgprot) pfn_pmd(page_to_pfn(page), (pgprot))
>
> diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
> index 532525e..121089d 100644
> --- a/arch/s390/mm/hugetlbpage.c
> +++ b/arch/s390/mm/hugetlbpage.c
> @@ -39,7 +39,7 @@ int arch_prepare_hugepage(struct page *page)
> if (!ptep)
> return -ENOMEM;
>
> - pte = mk_pte(page, PAGE_RW);
> + pte_val(pte) = addr;
> for (i = 0; i < PTRS_PER_PTE; i++) {
> set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte);
> pte_val(pte) += PAGE_SIZE;
> diff --git a/arch/sh/include/asm/hugetlb.h b/arch/sh/include/asm/hugetlb.h
> index b3808c7..699255d 100644
> --- a/arch/sh/include/asm/hugetlb.h
> +++ b/arch/sh/include/asm/hugetlb.h
> @@ -3,6 +3,7 @@
>
> #include <asm/cacheflush.h>
> #include <asm/page.h>
> +#include <asm-generic/hugetlb.h>
>
>
> static inline int is_hugepage_only_range(struct mm_struct *mm,
> diff --git a/arch/sparc/include/asm/hugetlb.h b/arch/sparc/include/asm/hugetlb.h
> index 7eb57d2..e4cab46 100644
> --- a/arch/sparc/include/asm/hugetlb.h
> +++ b/arch/sparc/include/asm/hugetlb.h
> @@ -2,6 +2,7 @@
> #define _ASM_SPARC64_HUGETLB_H
>
> #include <asm/page.h>
> +#include <asm-generic/hugetlb.h>
>
>
> void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
> diff --git a/arch/tile/include/asm/hugetlb.h b/arch/tile/include/asm/hugetlb.h
> index 0f885af..3257733 100644
> --- a/arch/tile/include/asm/hugetlb.h
> +++ b/arch/tile/include/asm/hugetlb.h
> @@ -16,6 +16,7 @@
> #define _ASM_TILE_HUGETLB_H
>
> #include <asm/page.h>
> +#include <asm-generic/hugetlb.h>
>
>
> static inline int is_hugepage_only_range(struct mm_struct *mm,
> diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h
> index bdd35db..a809121 100644
> --- a/arch/x86/include/asm/hugetlb.h
> +++ b/arch/x86/include/asm/hugetlb.h
> @@ -2,6 +2,7 @@
> #define _ASM_X86_HUGETLB_H
>
> #include <asm/page.h>
> +#include <asm-generic/hugetlb.h>
>
>
> static inline int is_hugepage_only_range(struct mm_struct *mm,
> diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h
> new file mode 100644
> index 0000000..d06079c
> --- /dev/null
> +++ b/include/asm-generic/hugetlb.h
> @@ -0,0 +1,40 @@
> +#ifndef _ASM_GENERIC_HUGETLB_H
> +#define _ASM_GENERIC_HUGETLB_H
> +
> +static inline pte_t mk_huge_pte(struct page *page, pgprot_t pgprot)
> +{
> + return mk_pte(page, pgprot);
> +}
> +
> +static inline int huge_pte_write(pte_t pte)
> +{
> + return pte_write(pte);
> +}
> +
> +static inline int huge_pte_dirty(pte_t pte)
> +{
> + return pte_dirty(pte);
> +}
> +
> +static inline pte_t huge_pte_mkwrite(pte_t pte)
> +{
> + return pte_mkwrite(pte);
> +}
> +
> +static inline pte_t huge_pte_mkdirty(pte_t pte)
> +{
> + return pte_mkdirty(pte);
> +}
> +
> +static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot)
> +{
> + return pte_modify(pte, newprot);
> +}
> +
> +static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
> + pte_t *ptep)
> +{
> + pte_clear(mm, addr, ptep);
> +}
> +
> +#endif /* _ASM_GENERIC_HUGETLB_H */
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index c65a8a5..43425ad 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2243,10 +2243,11 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
> pte_t entry;
>
> if (writable) {
> - entry =
> - pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
> + entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
> + vma->vm_page_prot)));
> } else {
> - entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
> + entry = huge_pte_wrprotect(mk_huge_pte(page,
> + vma->vm_page_prot));
> }
> entry = pte_mkyoung(entry);
> entry = pte_mkhuge(entry);
> @@ -2260,7 +2261,7 @@ static void set_huge_ptep_writable(struct vm_area_struct *vma,
> {
> pte_t entry;
>
> - entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
> + entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
> if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
> update_mmu_cache(vma, address, ptep);
> }
> @@ -2375,7 +2376,7 @@ again:
> * HWPoisoned hugepage is already unmapped and dropped reference
> */
> if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
> - pte_clear(mm, address, ptep);
> + huge_pte_clear(mm, address, ptep);
> continue;
> }
>
> @@ -2399,7 +2400,7 @@ again:
>
> pte = huge_ptep_get_and_clear(mm, address, ptep);
> tlb_remove_tlb_entry(tlb, ptep, address);
> - if (pte_dirty(pte))
> + if (huge_pte_dirty(pte))
> set_page_dirty(page);
>
> page_remove_rmap(page);
> @@ -2852,7 +2853,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
> * page now as it is used to determine if a reservation has been
> * consumed.
> */
> - if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
> + if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
> if (vma_needs_reservation(h, vma, address) < 0) {
> ret = VM_FAULT_OOM;
> goto out_mutex;
> @@ -2882,12 +2883,12 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
>
>
> if (flags & FAULT_FLAG_WRITE) {
> - if (!pte_write(entry)) {
> + if (!huge_pte_write(entry)) {
> ret = hugetlb_cow(mm, vma, address, ptep, entry,
> pagecache_page);
> goto out_page_table_lock;
> }
> - entry = pte_mkdirty(entry);
> + entry = huge_pte_mkdirty(entry);
> }
> entry = pte_mkyoung(entry);
> if (huge_ptep_set_access_flags(vma, address, ptep, entry,
> @@ -2958,7 +2959,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
> }
>
> if (absent ||
> - ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
> + ((flags & FOLL_WRITE) && !huge_pte_write(huge_ptep_get(pte)))) {
> int ret;
>
> spin_unlock(&mm->page_table_lock);
> @@ -3028,7 +3029,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
> }
> if (!huge_pte_none(huge_ptep_get(ptep))) {
> pte = huge_ptep_get_and_clear(mm, address, ptep);
> - pte = pte_mkhuge(pte_modify(pte, newprot));
> + pte = pte_mkhuge(huge_pte_modify(pte, newprot));
> pte = arch_make_huge_pte(pte, vma, NULL, 0);
> set_huge_pte_at(mm, address, ptep, pte);
> pages++;
> --
> 1.7.12.4
>

--
Michal Hocko
SUSE Labs
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