| Message ID | 20220615172926.546974-6-shy828301@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Cleanup transhuge_xxx helpers | expand |
On 15 Jun 10:29, Yang Shi wrote: > The page fault path checks THP eligibility with > __transhuge_page_enabled() which does the similar thing as > hugepage_vma_check(), so use hugepage_vma_check() instead. > > However page fault allows DAX and !anon_vma cases, so added a new flag, > in_pf, to hugepage_vma_check() to make page fault work correctly. > > The in_pf flag is also used to skip shmem and file THP for page fault > since shmem handles THP in its own shmem_fault() and file THP allocation > on fault is not supported yet. > > Also remove hugepage_vma_enabled() since hugepage_vma_check() is the > only caller now, it is not necessary to have a helper function. > > Signed-off-by: Yang Shi <shy828301@gmail.com> > --- > fs/proc/task_mmu.c | 2 +- > include/linux/huge_mm.h | 57 ++--------------------------------------- > mm/huge_memory.c | 51 ++++++++++++++++++++++++++++-------- > mm/khugepaged.c | 8 +++--- > mm/memory.c | 7 +++-- > 5 files changed, 52 insertions(+), 73 deletions(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 39a40ec181e7..cef72e49acc5 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -863,7 +863,7 @@ static int show_smap(struct seq_file *m, void *v) > __show_smap(m, &mss, false); > > seq_printf(m, "THPeligible: %d\n", > - hugepage_vma_check(vma, vma->vm_flags, true)); > + hugepage_vma_check(vma, vma->vm_flags, true, false)); > > if (arch_pkeys_enabled()) > seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma)); > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index aeb13119ee28..9d97d7ee6234 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -146,48 +146,6 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, > return true; > } > > -static inline bool transhuge_vma_enabled(struct vm_area_struct *vma, > - unsigned long vm_flags) > -{ > - /* Explicitly disabled through madvise. */ > - if ((vm_flags & VM_NOHUGEPAGE) || > - test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) > - return false; > - return true; > -} > - > -/* > - * to be used on vmas which are known to support THP. > - * Use transparent_hugepage_active otherwise > - */ > -static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma) > -{ > - > - /* > - * If the hardware/firmware marked hugepage support disabled. > - */ > - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX)) > - return false; > - > - if (!transhuge_vma_enabled(vma, vma->vm_flags)) > - return false; > - > - if (vma_is_temporary_stack(vma)) > - return false; > - > - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_FLAG)) > - return true; > - > - if (vma_is_dax(vma)) > - return true; > - > - if (transparent_hugepage_flags & > - (1 << TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)) > - return !!(vma->vm_flags & VM_HUGEPAGE); > - > - return false; > -} > - > static inline bool file_thp_enabled(struct vm_area_struct *vma) > { > struct inode *inode; > @@ -204,7 +162,7 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma) > > bool hugepage_vma_check(struct vm_area_struct *vma, > unsigned long vm_flags, > - bool smaps); > + bool smaps, bool in_pf); > > #define transparent_hugepage_use_zero_page() \ > (transparent_hugepage_flags & \ > @@ -348,11 +306,6 @@ static inline bool folio_test_pmd_mappable(struct folio *folio) > return false; > } > > -static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma) > -{ > - return false; > -} > - > static inline bool transparent_hugepage_active(struct vm_area_struct *vma) > { > return false; > @@ -364,15 +317,9 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, > return false; > } > > -static inline bool transhuge_vma_enabled(struct vm_area_struct *vma, > - unsigned long vm_flags) > -{ > - return false; > -} > - > static inline bool hugepage_vma_check(struct vm_area_struct *vma, > unsigned long vm_flags, > - bool smaps) > + bool smaps, bool in_pf) > { > return false; > } > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index a28c6100b491..d0c37d99917b 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -71,24 +71,50 @@ unsigned long huge_zero_pfn __read_mostly = ~0UL; > > bool hugepage_vma_check(struct vm_area_struct *vma, > unsigned long vm_flags, > - bool smaps) > + bool smaps, bool in_pf) > { > - if (!transhuge_vma_enabled(vma, vm_flags)) > + /* > + * Explicitly disabled through madvise or prctl, or some > + * architectures may disable THP for some mappings, for > + * example, s390 kvm. > + * */ > + if ((vm_flags & VM_NOHUGEPAGE) || > + test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) > return false; > - > - if (vm_flags & VM_NO_KHUGEPAGED) > + /* > + * If the hardware/firmware marked hugepage support disabled. > + */ > + if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX)) > return false; > > - /* Don't run khugepaged against DAX vma */ > + /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ > if (vma_is_dax(vma)) > + return in_pf; > + > + /* > + * Special VMA and hugetlb VMA. > + * Must be checked after dax since some dax mappings may have > + * VM_MIXEDMAP set. > + */ > + if (vm_flags & VM_NO_KHUGEPAGED) > return false; > > - /* Check alignment for file vma and size for both file and anon vma */ > - if (!transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) > + /* > + * Check alignment for file vma and size for both file and anon vma. > + * > + * Skip the check for page fault. Huge fault does the check in fault > + * handlers. And this check is not suitable for huge PUD fault. > + */ > + if (!in_pf && > + !transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) > return false; Good catch. > > - /* Enabled via shmem mount options or sysfs settings. */ > - if (shmem_file(vma->vm_file)) > + /* > + * Enabled via shmem mount options or sysfs settings. > + * Must be done before hugepage flags check since shmem has its > + * own flags. > + */ > + if (!in_pf && shmem_file(vma->vm_file)) > return shmem_huge_enabled(vma); > > if (!khugepaged_enabled()) > @@ -99,7 +125,7 @@ bool hugepage_vma_check(struct vm_area_struct *vma, > return false; > > /* Only regular file is valid */ > - if (file_thp_enabled(vma)) > + if (!in_pf && file_thp_enabled(vma)) > return true; > > if (!vma_is_anonymous(vma)) > @@ -111,9 +137,12 @@ bool hugepage_vma_check(struct vm_area_struct *vma, > /* > * THPeligible bit of smaps should show 1 for proper VMAs even > * though anon_vma is not initialized yet. > + * > + * Allow page fault since anon_vma may be not initialized until > + * the first page fault. > */ > if (!vma->anon_vma) > - return smaps; > + return (smaps || in_pf); > > return true; > } > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 3afd87f8c0b1..2a676f37c921 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -473,7 +473,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma, > { > if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) && > khugepaged_enabled()) { > - if (hugepage_vma_check(vma, vm_flags, false)) > + if (hugepage_vma_check(vma, vm_flags, false, false)) > __khugepaged_enter(vma->vm_mm); > } > } > @@ -918,7 +918,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, > > if (!transhuge_vma_suitable(vma, address)) > return SCAN_ADDRESS_RANGE; > - if (!hugepage_vma_check(vma, vma->vm_flags, false)) > + if (!hugepage_vma_check(vma, vma->vm_flags, false, false)) > return SCAN_VMA_CHECK; > /* > * Anon VMA expected, the address may be unmapped then > @@ -1408,7 +1408,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) > * the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check() > * will not fail the vma for missing VM_HUGEPAGE > */ > - if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false)) > + if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false, false)) > return; > > /* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */ > @@ -2103,7 +2103,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, > progress++; > break; > } > - if (!hugepage_vma_check(vma, vma->vm_flags, false)) { > + if (!hugepage_vma_check(vma, vma->vm_flags, false, false)) { > skip: > progress++; > continue; > diff --git a/mm/memory.c b/mm/memory.c > index be724238a9d3..fee2884481f2 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4985,6 +4985,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, > .gfp_mask = __get_fault_gfp_mask(vma), > }; > struct mm_struct *mm = vma->vm_mm; > + unsigned long vm_flags = vma->vm_flags; > pgd_t *pgd; > p4d_t *p4d; > vm_fault_t ret; > @@ -4998,7 +4999,8 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, > if (!vmf.pud) > return VM_FAULT_OOM; > retry_pud: > - if (pud_none(*vmf.pud) && __transparent_hugepage_enabled(vma)) { > + if (pud_none(*vmf.pud) && > + hugepage_vma_check(vma, vm_flags, false, true)) { > ret = create_huge_pud(&vmf); > if (!(ret & VM_FAULT_FALLBACK)) > return ret; > @@ -5031,7 +5033,8 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, > if (pud_trans_unstable(vmf.pud)) > goto retry_pud; > > - if (pmd_none(*vmf.pmd) && __transparent_hugepage_enabled(vma)) { > + if (pmd_none(*vmf.pmd) && > + hugepage_vma_check(vma, vm_flags, false, true)) { > ret = create_huge_pmd(&vmf); > if (!(ret & VM_FAULT_FALLBACK)) > return ret; > -- > 2.26.3 > Thanks for the updates / improvements! Reviewed-by: Zach O'Keefe
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 39a40ec181e7..cef72e49acc5 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -863,7 +863,7 @@ static int show_smap(struct seq_file *m, void *v) __show_smap(m, &mss, false); seq_printf(m, "THPeligible: %d\n", - hugepage_vma_check(vma, vma->vm_flags, true)); + hugepage_vma_check(vma, vma->vm_flags, true, false)); if (arch_pkeys_enabled()) seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma)); diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index aeb13119ee28..9d97d7ee6234 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -146,48 +146,6 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, return true; } -static inline bool transhuge_vma_enabled(struct vm_area_struct *vma, - unsigned long vm_flags) -{ - /* Explicitly disabled through madvise. */ - if ((vm_flags & VM_NOHUGEPAGE) || - test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) - return false; - return true; -} - -/* - * to be used on vmas which are known to support THP. - * Use transparent_hugepage_active otherwise - */ -static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma) -{ - - /* - * If the hardware/firmware marked hugepage support disabled. - */ - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX)) - return false; - - if (!transhuge_vma_enabled(vma, vma->vm_flags)) - return false; - - if (vma_is_temporary_stack(vma)) - return false; - - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_FLAG)) - return true; - - if (vma_is_dax(vma)) - return true; - - if (transparent_hugepage_flags & - (1 << TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)) - return !!(vma->vm_flags & VM_HUGEPAGE); - - return false; -} - static inline bool file_thp_enabled(struct vm_area_struct *vma) { struct inode *inode; @@ -204,7 +162,7 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma) bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, - bool smaps); + bool smaps, bool in_pf); #define transparent_hugepage_use_zero_page() \ (transparent_hugepage_flags & \ @@ -348,11 +306,6 @@ static inline bool folio_test_pmd_mappable(struct folio *folio) return false; } -static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma) -{ - return false; -} - static inline bool transparent_hugepage_active(struct vm_area_struct *vma) { return false; @@ -364,15 +317,9 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, return false; } -static inline bool transhuge_vma_enabled(struct vm_area_struct *vma, - unsigned long vm_flags) -{ - return false; -} - static inline bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, - bool smaps) + bool smaps, bool in_pf) { return false; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a28c6100b491..d0c37d99917b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -71,24 +71,50 @@ unsigned long huge_zero_pfn __read_mostly = ~0UL; bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, - bool smaps) + bool smaps, bool in_pf) { - if (!transhuge_vma_enabled(vma, vm_flags)) + /* + * Explicitly disabled through madvise or prctl, or some + * architectures may disable THP for some mappings, for + * example, s390 kvm. + * */ + if ((vm_flags & VM_NOHUGEPAGE) || + test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) return false; - - if (vm_flags & VM_NO_KHUGEPAGED) + /* + * If the hardware/firmware marked hugepage support disabled. + */ + if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX)) return false; - /* Don't run khugepaged against DAX vma */ + /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ if (vma_is_dax(vma)) + return in_pf; + + /* + * Special VMA and hugetlb VMA. + * Must be checked after dax since some dax mappings may have + * VM_MIXEDMAP set. + */ + if (vm_flags & VM_NO_KHUGEPAGED) return false; - /* Check alignment for file vma and size for both file and anon vma */ - if (!transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) + /* + * Check alignment for file vma and size for both file and anon vma. + * + * Skip the check for page fault. Huge fault does the check in fault + * handlers. And this check is not suitable for huge PUD fault. + */ + if (!in_pf && + !transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) return false; - /* Enabled via shmem mount options or sysfs settings. */ - if (shmem_file(vma->vm_file)) + /* + * Enabled via shmem mount options or sysfs settings. + * Must be done before hugepage flags check since shmem has its + * own flags. + */ + if (!in_pf && shmem_file(vma->vm_file)) return shmem_huge_enabled(vma); if (!khugepaged_enabled()) @@ -99,7 +125,7 @@ bool hugepage_vma_check(struct vm_area_struct *vma, return false; /* Only regular file is valid */ - if (file_thp_enabled(vma)) + if (!in_pf && file_thp_enabled(vma)) return true; if (!vma_is_anonymous(vma)) @@ -111,9 +137,12 @@ bool hugepage_vma_check(struct vm_area_struct *vma, /* * THPeligible bit of smaps should show 1 for proper VMAs even * though anon_vma is not initialized yet. + * + * Allow page fault since anon_vma may be not initialized until + * the first page fault. */ if (!vma->anon_vma) - return smaps; + return (smaps || in_pf); return true; } diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 3afd87f8c0b1..2a676f37c921 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -473,7 +473,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma, { if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) && khugepaged_enabled()) { - if (hugepage_vma_check(vma, vm_flags, false)) + if (hugepage_vma_check(vma, vm_flags, false, false)) __khugepaged_enter(vma->vm_mm); } } @@ -918,7 +918,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, if (!transhuge_vma_suitable(vma, address)) return SCAN_ADDRESS_RANGE; - if (!hugepage_vma_check(vma, vma->vm_flags, false)) + if (!hugepage_vma_check(vma, vma->vm_flags, false, false)) return SCAN_VMA_CHECK; /* * Anon VMA expected, the address may be unmapped then @@ -1408,7 +1408,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) * the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check() * will not fail the vma for missing VM_HUGEPAGE */ - if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false)) + if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false, false)) return; /* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */ @@ -2103,7 +2103,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, progress++; break; } - if (!hugepage_vma_check(vma, vma->vm_flags, false)) { + if (!hugepage_vma_check(vma, vma->vm_flags, false, false)) { skip: progress++; continue; diff --git a/mm/memory.c b/mm/memory.c index be724238a9d3..fee2884481f2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4985,6 +4985,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, .gfp_mask = __get_fault_gfp_mask(vma), }; struct mm_struct *mm = vma->vm_mm; + unsigned long vm_flags = vma->vm_flags; pgd_t *pgd; p4d_t *p4d; vm_fault_t ret; @@ -4998,7 +4999,8 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, if (!vmf.pud) return VM_FAULT_OOM; retry_pud: - if (pud_none(*vmf.pud) && __transparent_hugepage_enabled(vma)) { + if (pud_none(*vmf.pud) && + hugepage_vma_check(vma, vm_flags, false, true)) { ret = create_huge_pud(&vmf); if (!(ret & VM_FAULT_FALLBACK)) return ret; @@ -5031,7 +5033,8 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, if (pud_trans_unstable(vmf.pud)) goto retry_pud; - if (pmd_none(*vmf.pmd) && __transparent_hugepage_enabled(vma)) { + if (pmd_none(*vmf.pmd) && + hugepage_vma_check(vma, vm_flags, false, true)) { ret = create_huge_pmd(&vmf); if (!(ret & VM_FAULT_FALLBACK)) return ret;
The page fault path checks THP eligibility with __transhuge_page_enabled() which does the similar thing as hugepage_vma_check(), so use hugepage_vma_check() instead. However page fault allows DAX and !anon_vma cases, so added a new flag, in_pf, to hugepage_vma_check() to make page fault work correctly. The in_pf flag is also used to skip shmem and file THP for page fault since shmem handles THP in its own shmem_fault() and file THP allocation on fault is not supported yet. Also remove hugepage_vma_enabled() since hugepage_vma_check() is the only caller now, it is not necessary to have a helper function. Signed-off-by: Yang Shi <shy828301@gmail.com> --- fs/proc/task_mmu.c | 2 +- include/linux/huge_mm.h | 57 ++--------------------------------------- mm/huge_memory.c | 51 ++++++++++++++++++++++++++++-------- mm/khugepaged.c | 8 +++--- mm/memory.c | 7 +++-- 5 files changed, 52 insertions(+), 73 deletions(-)