| Message ID | 20240202080756.1453939-22-ryan.roberts@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Transparent Contiguous PTEs for User Mappings | expand |
On Fri, Feb 02, 2024 at 08:07:52AM +0000, Ryan Roberts wrote: > Optimize the contpte implementation to fix some of the > exit/munmap/dontneed performance regression introduced by the initial > contpte commit. Subsequent patches will solve it entirely. > > During exit(), munmap() or madvise(MADV_DONTNEED), mappings must be > cleared. Previously this was done 1 PTE at a time. But the core-mm > supports batched clear via the new [get_and_]clear_full_ptes() APIs. So > let's implement those APIs and for fully covered contpte mappings, we no > longer need to unfold the contpte. This significantly reduces unfolding > operations, reducing the number of tlbis that must be issued. > > Tested-by: John Hubbard <jhubbard@nvidia.com> > Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> > --- > arch/arm64/include/asm/pgtable.h | 67 ++++++++++++++++++++++++++++++++ > arch/arm64/mm/contpte.c | 17 ++++++++ > 2 files changed, 84 insertions(+) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index c07f0d563733..ad04adb7b87f 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -965,6 +965,37 @@ static inline pte_t __ptep_get_and_clear(struct mm_struct *mm, > return pte; > } > > +static inline void __clear_full_ptes(struct mm_struct *mm, unsigned long addr, > + pte_t *ptep, unsigned int nr, int full) > +{ > + for (;;) { > + __ptep_get_and_clear(mm, addr, ptep); > + if (--nr == 0) > + break; > + ptep++; > + addr += PAGE_SIZE; > + } > +} The loop construct is a bit odd; can't this be: while (nr--) { __ptep_get_and_clear(mm, addr, ptep); ptep++; addr += PAGE_SIZE; } ... or: do { __ptep_get_and_clear(mm, addr, ptep); ptep++; addr += PAGE_SIZE; } while (--nr); ... ? Otherwise, this looks good to me. Mark. > + > +static inline pte_t __get_and_clear_full_ptes(struct mm_struct *mm, > + unsigned long addr, pte_t *ptep, > + unsigned int nr, int full) > +{ > + pte_t pte, tmp_pte; > + > + pte = __ptep_get_and_clear(mm, addr, ptep); > + while (--nr) { > + ptep++; > + addr += PAGE_SIZE; > + tmp_pte = __ptep_get_and_clear(mm, addr, ptep); > + if (pte_dirty(tmp_pte)) > + pte = pte_mkdirty(pte); > + if (pte_young(tmp_pte)) > + pte = pte_mkyoung(pte); > + } > + return pte; > +} > + > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR > static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, > @@ -1167,6 +1198,11 @@ extern pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte); > extern pte_t contpte_ptep_get_lockless(pte_t *orig_ptep); > extern void contpte_set_ptes(struct mm_struct *mm, unsigned long addr, > pte_t *ptep, pte_t pte, unsigned int nr); > +extern void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr, > + pte_t *ptep, unsigned int nr, int full); > +extern pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, > + unsigned long addr, pte_t *ptep, > + unsigned int nr, int full); > extern int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, > unsigned long addr, pte_t *ptep); > extern int contpte_ptep_clear_flush_young(struct vm_area_struct *vma, > @@ -1254,6 +1290,35 @@ static inline void pte_clear(struct mm_struct *mm, > __pte_clear(mm, addr, ptep); > } > > +#define clear_full_ptes clear_full_ptes > +static inline void clear_full_ptes(struct mm_struct *mm, unsigned long addr, > + pte_t *ptep, unsigned int nr, int full) > +{ > + if (likely(nr == 1)) { > + contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep)); > + __clear_full_ptes(mm, addr, ptep, nr, full); > + } else { > + contpte_clear_full_ptes(mm, addr, ptep, nr, full); > + } > +} > + > +#define get_and_clear_full_ptes get_and_clear_full_ptes > +static inline pte_t get_and_clear_full_ptes(struct mm_struct *mm, > + unsigned long addr, pte_t *ptep, > + unsigned int nr, int full) > +{ > + pte_t pte; > + > + if (likely(nr == 1)) { > + contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep)); > + pte = __get_and_clear_full_ptes(mm, addr, ptep, nr, full); > + } else { > + pte = contpte_get_and_clear_full_ptes(mm, addr, ptep, nr, full); > + } > + > + return pte; > +} > + > #define __HAVE_ARCH_PTEP_GET_AND_CLEAR > static inline pte_t ptep_get_and_clear(struct mm_struct *mm, > unsigned long addr, pte_t *ptep) > @@ -1338,6 +1403,8 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma, > #define set_pte __set_pte > #define set_ptes __set_ptes > #define pte_clear __pte_clear > +#define clear_full_ptes __clear_full_ptes > +#define get_and_clear_full_ptes __get_and_clear_full_ptes > #define __HAVE_ARCH_PTEP_GET_AND_CLEAR > #define ptep_get_and_clear __ptep_get_and_clear > #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG > diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c > index c85e64baf03b..80346108450b 100644 > --- a/arch/arm64/mm/contpte.c > +++ b/arch/arm64/mm/contpte.c > @@ -207,6 +207,23 @@ void contpte_set_ptes(struct mm_struct *mm, unsigned long addr, > } > EXPORT_SYMBOL(contpte_set_ptes); > > +void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr, > + pte_t *ptep, unsigned int nr, int full) > +{ > + contpte_try_unfold_partial(mm, addr, ptep, nr); > + __clear_full_ptes(mm, addr, ptep, nr, full); > +} > +EXPORT_SYMBOL(contpte_clear_full_ptes); > + > +pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, > + unsigned long addr, pte_t *ptep, > + unsigned int nr, int full) > +{ > + contpte_try_unfold_partial(mm, addr, ptep, nr); > + return __get_and_clear_full_ptes(mm, addr, ptep, nr, full); > +} > +EXPORT_SYMBOL(contpte_get_and_clear_full_ptes); > + > int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, > unsigned long addr, pte_t *ptep) > { > -- > 2.25.1 >
On 13/02/2024 16:43, Mark Rutland wrote: > On Fri, Feb 02, 2024 at 08:07:52AM +0000, Ryan Roberts wrote: >> Optimize the contpte implementation to fix some of the >> exit/munmap/dontneed performance regression introduced by the initial >> contpte commit. Subsequent patches will solve it entirely. >> >> During exit(), munmap() or madvise(MADV_DONTNEED), mappings must be >> cleared. Previously this was done 1 PTE at a time. But the core-mm >> supports batched clear via the new [get_and_]clear_full_ptes() APIs. So >> let's implement those APIs and for fully covered contpte mappings, we no >> longer need to unfold the contpte. This significantly reduces unfolding >> operations, reducing the number of tlbis that must be issued. >> >> Tested-by: John Hubbard <jhubbard@nvidia.com> >> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> >> --- >> arch/arm64/include/asm/pgtable.h | 67 ++++++++++++++++++++++++++++++++ >> arch/arm64/mm/contpte.c | 17 ++++++++ >> 2 files changed, 84 insertions(+) >> >> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h >> index c07f0d563733..ad04adb7b87f 100644 >> --- a/arch/arm64/include/asm/pgtable.h >> +++ b/arch/arm64/include/asm/pgtable.h >> @@ -965,6 +965,37 @@ static inline pte_t __ptep_get_and_clear(struct mm_struct *mm, >> return pte; >> } >> >> +static inline void __clear_full_ptes(struct mm_struct *mm, unsigned long addr, >> + pte_t *ptep, unsigned int nr, int full) >> +{ >> + for (;;) { >> + __ptep_get_and_clear(mm, addr, ptep); >> + if (--nr == 0) >> + break; >> + ptep++; >> + addr += PAGE_SIZE; >> + } >> +} > > The loop construct is a bit odd; can't this be: I found it a little odd at first, but its avoiding the ptep and addr increments the last time through the loop. Its the preferred pattern for these functions in core-mm. See default set_ptes(), wrprotect_ptes(), clear_full_ptes() in include/linux/pgtable.h. So I'd prefer to leave it as is so that we match them. What do you think? > > while (nr--) { > __ptep_get_and_clear(mm, addr, ptep); > ptep++; > addr += PAGE_SIZE; > } > > ... or: > > do { > __ptep_get_and_clear(mm, addr, ptep); > ptep++; > addr += PAGE_SIZE; > } while (--nr); > > ... ? > > Otherwise, this looks good to me. > > Mark. > >> + >> +static inline pte_t __get_and_clear_full_ptes(struct mm_struct *mm, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr, int full) >> +{ >> + pte_t pte, tmp_pte; >> + >> + pte = __ptep_get_and_clear(mm, addr, ptep); >> + while (--nr) { >> + ptep++; >> + addr += PAGE_SIZE; >> + tmp_pte = __ptep_get_and_clear(mm, addr, ptep); >> + if (pte_dirty(tmp_pte)) >> + pte = pte_mkdirty(pte); >> + if (pte_young(tmp_pte)) >> + pte = pte_mkyoung(pte); >> + } >> + return pte; >> +} >> + >> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >> #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR >> static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, >> @@ -1167,6 +1198,11 @@ extern pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte); >> extern pte_t contpte_ptep_get_lockless(pte_t *orig_ptep); >> extern void contpte_set_ptes(struct mm_struct *mm, unsigned long addr, >> pte_t *ptep, pte_t pte, unsigned int nr); >> +extern void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr, >> + pte_t *ptep, unsigned int nr, int full); >> +extern pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr, int full); >> extern int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, >> unsigned long addr, pte_t *ptep); >> extern int contpte_ptep_clear_flush_young(struct vm_area_struct *vma, >> @@ -1254,6 +1290,35 @@ static inline void pte_clear(struct mm_struct *mm, >> __pte_clear(mm, addr, ptep); >> } >> >> +#define clear_full_ptes clear_full_ptes >> +static inline void clear_full_ptes(struct mm_struct *mm, unsigned long addr, >> + pte_t *ptep, unsigned int nr, int full) >> +{ >> + if (likely(nr == 1)) { >> + contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep)); >> + __clear_full_ptes(mm, addr, ptep, nr, full); >> + } else { >> + contpte_clear_full_ptes(mm, addr, ptep, nr, full); >> + } >> +} >> + >> +#define get_and_clear_full_ptes get_and_clear_full_ptes >> +static inline pte_t get_and_clear_full_ptes(struct mm_struct *mm, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr, int full) >> +{ >> + pte_t pte; >> + >> + if (likely(nr == 1)) { >> + contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep)); >> + pte = __get_and_clear_full_ptes(mm, addr, ptep, nr, full); >> + } else { >> + pte = contpte_get_and_clear_full_ptes(mm, addr, ptep, nr, full); >> + } >> + >> + return pte; >> +} >> + >> #define __HAVE_ARCH_PTEP_GET_AND_CLEAR >> static inline pte_t ptep_get_and_clear(struct mm_struct *mm, >> unsigned long addr, pte_t *ptep) >> @@ -1338,6 +1403,8 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma, >> #define set_pte __set_pte >> #define set_ptes __set_ptes >> #define pte_clear __pte_clear >> +#define clear_full_ptes __clear_full_ptes >> +#define get_and_clear_full_ptes __get_and_clear_full_ptes >> #define __HAVE_ARCH_PTEP_GET_AND_CLEAR >> #define ptep_get_and_clear __ptep_get_and_clear >> #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG >> diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c >> index c85e64baf03b..80346108450b 100644 >> --- a/arch/arm64/mm/contpte.c >> +++ b/arch/arm64/mm/contpte.c >> @@ -207,6 +207,23 @@ void contpte_set_ptes(struct mm_struct *mm, unsigned long addr, >> } >> EXPORT_SYMBOL(contpte_set_ptes); >> >> +void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr, >> + pte_t *ptep, unsigned int nr, int full) >> +{ >> + contpte_try_unfold_partial(mm, addr, ptep, nr); >> + __clear_full_ptes(mm, addr, ptep, nr, full); >> +} >> +EXPORT_SYMBOL(contpte_clear_full_ptes); >> + >> +pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr, int full) >> +{ >> + contpte_try_unfold_partial(mm, addr, ptep, nr); >> + return __get_and_clear_full_ptes(mm, addr, ptep, nr, full); >> +} >> +EXPORT_SYMBOL(contpte_get_and_clear_full_ptes); >> + >> int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, >> unsigned long addr, pte_t *ptep) >> { >> -- >> 2.25.1 >>
On Tue, Feb 13, 2024 at 04:48:50PM +0000, Ryan Roberts wrote: > On 13/02/2024 16:43, Mark Rutland wrote: > > On Fri, Feb 02, 2024 at 08:07:52AM +0000, Ryan Roberts wrote: > >> +static inline void __clear_full_ptes(struct mm_struct *mm, unsigned long addr, > >> + pte_t *ptep, unsigned int nr, int full) > >> +{ > >> + for (;;) { > >> + __ptep_get_and_clear(mm, addr, ptep); > >> + if (--nr == 0) > >> + break; > >> + ptep++; > >> + addr += PAGE_SIZE; > >> + } > >> +} > > > > The loop construct is a bit odd; can't this be: > > I found it a little odd at first, but its avoiding the ptep and addr increments > the last time through the loop. Its the preferred pattern for these functions in > core-mm. See default set_ptes(), wrprotect_ptes(), clear_full_ptes() in > include/linux/pgtable.h. > > So I'd prefer to leave it as is so that we match them. What do you think? That's fair enough; it I'm happy with it as-is. Mark.
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index c07f0d563733..ad04adb7b87f 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -965,6 +965,37 @@ static inline pte_t __ptep_get_and_clear(struct mm_struct *mm, return pte; } +static inline void __clear_full_ptes(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned int nr, int full) +{ + for (;;) { + __ptep_get_and_clear(mm, addr, ptep); + if (--nr == 0) + break; + ptep++; + addr += PAGE_SIZE; + } +} + +static inline pte_t __get_and_clear_full_ptes(struct mm_struct *mm, + unsigned long addr, pte_t *ptep, + unsigned int nr, int full) +{ + pte_t pte, tmp_pte; + + pte = __ptep_get_and_clear(mm, addr, ptep); + while (--nr) { + ptep++; + addr += PAGE_SIZE; + tmp_pte = __ptep_get_and_clear(mm, addr, ptep); + if (pte_dirty(tmp_pte)) + pte = pte_mkdirty(pte); + if (pte_young(tmp_pte)) + pte = pte_mkyoung(pte); + } + return pte; +} + #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, @@ -1167,6 +1198,11 @@ extern pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte); extern pte_t contpte_ptep_get_lockless(pte_t *orig_ptep); extern void contpte_set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte, unsigned int nr); +extern void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned int nr, int full); +extern pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, + unsigned long addr, pte_t *ptep, + unsigned int nr, int full); extern int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep); extern int contpte_ptep_clear_flush_young(struct vm_area_struct *vma, @@ -1254,6 +1290,35 @@ static inline void pte_clear(struct mm_struct *mm, __pte_clear(mm, addr, ptep); } +#define clear_full_ptes clear_full_ptes +static inline void clear_full_ptes(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned int nr, int full) +{ + if (likely(nr == 1)) { + contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep)); + __clear_full_ptes(mm, addr, ptep, nr, full); + } else { + contpte_clear_full_ptes(mm, addr, ptep, nr, full); + } +} + +#define get_and_clear_full_ptes get_and_clear_full_ptes +static inline pte_t get_and_clear_full_ptes(struct mm_struct *mm, + unsigned long addr, pte_t *ptep, + unsigned int nr, int full) +{ + pte_t pte; + + if (likely(nr == 1)) { + contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep)); + pte = __get_and_clear_full_ptes(mm, addr, ptep, nr, full); + } else { + pte = contpte_get_and_clear_full_ptes(mm, addr, ptep, nr, full); + } + + return pte; +} + #define __HAVE_ARCH_PTEP_GET_AND_CLEAR static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) @@ -1338,6 +1403,8 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma, #define set_pte __set_pte #define set_ptes __set_ptes #define pte_clear __pte_clear +#define clear_full_ptes __clear_full_ptes +#define get_and_clear_full_ptes __get_and_clear_full_ptes #define __HAVE_ARCH_PTEP_GET_AND_CLEAR #define ptep_get_and_clear __ptep_get_and_clear #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c index c85e64baf03b..80346108450b 100644 --- a/arch/arm64/mm/contpte.c +++ b/arch/arm64/mm/contpte.c @@ -207,6 +207,23 @@ void contpte_set_ptes(struct mm_struct *mm, unsigned long addr, } EXPORT_SYMBOL(contpte_set_ptes); +void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned int nr, int full) +{ + contpte_try_unfold_partial(mm, addr, ptep, nr); + __clear_full_ptes(mm, addr, ptep, nr, full); +} +EXPORT_SYMBOL(contpte_clear_full_ptes); + +pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, + unsigned long addr, pte_t *ptep, + unsigned int nr, int full) +{ + contpte_try_unfold_partial(mm, addr, ptep, nr); + return __get_and_clear_full_ptes(mm, addr, ptep, nr, full); +} +EXPORT_SYMBOL(contpte_get_and_clear_full_ptes); + int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) {