| Message ID | 20240726150728.3159964-3-david@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: split PTE/PMD PT table Kconfig cleanups+clarifications | expand |
On Fri, Jul 26, 2024 at 05:07:27PM +0200, David Hildenbrand wrote: > Sharing page tables between processes but falling back to per-MM page > table locks cannot possibly work. > > So, let's make sure that we do have split PMD locks by adding a new > Kconfig option and letting that depend on CONFIG_SPLIT_PMD_PTLOCKS. > > Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> > --- > fs/Kconfig | 4 ++++ > include/linux/hugetlb.h | 5 ++--- > mm/hugetlb.c | 8 ++++---- > 3 files changed, 10 insertions(+), 7 deletions(-) > > diff --git a/fs/Kconfig b/fs/Kconfig > index a46b0cbc4d8f6..0e4efec1d92e6 100644 > --- a/fs/Kconfig > +++ b/fs/Kconfig > @@ -288,6 +288,10 @@ config HUGETLB_PAGE_OPTIMIZE_VMEMMAP > depends on ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP > depends on SPARSEMEM_VMEMMAP > > +config HUGETLB_PMD_PAGE_TABLE_SHARING > + def_bool HUGETLB_PAGE > + depends on ARCH_WANT_HUGE_PMD_SHARE && SPLIT_PMD_PTLOCKS > + > config ARCH_HAS_GIGANTIC_PAGE > bool > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index da800e56fe590..4d2f3224ff027 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -1243,7 +1243,7 @@ static inline __init void hugetlb_cma_reserve(int order) > } > #endif > > -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE > +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING > static inline bool hugetlb_pmd_shared(pte_t *pte) > { > return page_count(virt_to_page(pte)) > 1; > @@ -1279,8 +1279,7 @@ bool __vma_private_lock(struct vm_area_struct *vma); > static inline pte_t * > hugetlb_walk(struct vm_area_struct *vma, unsigned long addr, unsigned long sz) > { > -#if defined(CONFIG_HUGETLB_PAGE) && \ > - defined(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) && defined(CONFIG_LOCKDEP) > +#if defined(CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING) && defined(CONFIG_LOCKDEP) > struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; > > /* > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 0858a18272073..c4d94e122c41f 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -7211,7 +7211,7 @@ long hugetlb_unreserve_pages(struct inode *inode, long start, long end, > return 0; > } > > -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE > +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING > static unsigned long page_table_shareable(struct vm_area_struct *svma, > struct vm_area_struct *vma, > unsigned long addr, pgoff_t idx) > @@ -7373,7 +7373,7 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, > return 1; > } > > -#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ > +#else /* !CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ > > pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, > unsigned long addr, pud_t *pud) > @@ -7396,7 +7396,7 @@ bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr) > { > return false; > } > -#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ > +#endif /* CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ > > #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB > pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, > @@ -7494,7 +7494,7 @@ unsigned long hugetlb_mask_last_page(struct hstate *h) > /* See description above. Architectures can provide their own version. */ > __weak unsigned long hugetlb_mask_last_page(struct hstate *h) > { > -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE > +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING > if (huge_page_size(h) == PMD_SIZE) > return PUD_SIZE - PMD_SIZE; > #endif > -- > 2.45.2 > >
diff --git a/fs/Kconfig b/fs/Kconfig index a46b0cbc4d8f6..0e4efec1d92e6 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -288,6 +288,10 @@ config HUGETLB_PAGE_OPTIMIZE_VMEMMAP depends on ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP depends on SPARSEMEM_VMEMMAP +config HUGETLB_PMD_PAGE_TABLE_SHARING + def_bool HUGETLB_PAGE + depends on ARCH_WANT_HUGE_PMD_SHARE && SPLIT_PMD_PTLOCKS + config ARCH_HAS_GIGANTIC_PAGE bool diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index da800e56fe590..4d2f3224ff027 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -1243,7 +1243,7 @@ static inline __init void hugetlb_cma_reserve(int order) } #endif -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING static inline bool hugetlb_pmd_shared(pte_t *pte) { return page_count(virt_to_page(pte)) > 1; @@ -1279,8 +1279,7 @@ bool __vma_private_lock(struct vm_area_struct *vma); static inline pte_t * hugetlb_walk(struct vm_area_struct *vma, unsigned long addr, unsigned long sz) { -#if defined(CONFIG_HUGETLB_PAGE) && \ - defined(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) && defined(CONFIG_LOCKDEP) +#if defined(CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING) && defined(CONFIG_LOCKDEP) struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; /* diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0858a18272073..c4d94e122c41f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -7211,7 +7211,7 @@ long hugetlb_unreserve_pages(struct inode *inode, long start, long end, return 0; } -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING static unsigned long page_table_shareable(struct vm_area_struct *svma, struct vm_area_struct *vma, unsigned long addr, pgoff_t idx) @@ -7373,7 +7373,7 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, return 1; } -#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ +#else /* !CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pud_t *pud) @@ -7396,7 +7396,7 @@ bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr) { return false; } -#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ +#endif /* CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, @@ -7494,7 +7494,7 @@ unsigned long hugetlb_mask_last_page(struct hstate *h) /* See description above. Architectures can provide their own version. */ __weak unsigned long hugetlb_mask_last_page(struct hstate *h) { -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING if (huge_page_size(h) == PMD_SIZE) return PUD_SIZE - PMD_SIZE; #endif
Sharing page tables between processes but falling back to per-MM page table locks cannot possibly work. So, let's make sure that we do have split PMD locks by adding a new Kconfig option and letting that depend on CONFIG_SPLIT_PMD_PTLOCKS. Signed-off-by: David Hildenbrand <david@redhat.com> --- fs/Kconfig | 4 ++++ include/linux/hugetlb.h | 5 ++--- mm/hugetlb.c | 8 ++++---- 3 files changed, 10 insertions(+), 7 deletions(-)