From ea81bae46032022656d45d4a395f1bf3b96697f0 Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Tue, 1 Oct 2019 10:37:33 +0200 Subject: mm: Remove BUG_ON mmap_sem not held from xxx_trans_huge_lock() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The caller needs to make sure that the vma is not torn down during the lock operation and can also use the i_mmap_rwsem for file-backed vmas. Remove the BUG_ON. We could, as an alternative, add a test that either vma->vm_mm->mmap_sem or vma->vm_file->f_mapping->i_mmap_rwsem are held. Cc: Andrew Morton Cc: Matthew Wilcox Cc: Will Deacon Cc: Peter Zijlstra Cc: Rik van Riel Cc: Minchan Kim Cc: Michal Hocko Cc: Huang Ying Cc: Jérôme Glisse Cc: Kirill A. Shutemov Signed-off-by: Thomas Hellstrom Acked-by: Kirill A. Shutemov --- include/linux/huge_mm.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 93d5cf0bc716..0b84e13e88e2 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -216,7 +216,6 @@ static inline int is_swap_pmd(pmd_t pmd) static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) { - VM_BUG_ON_VMA(!rwsem_is_locked(&vma->vm_mm->mmap_sem), vma); if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) return __pmd_trans_huge_lock(pmd, vma); else @@ -225,7 +224,6 @@ static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd, static inline spinlock_t *pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) { - VM_BUG_ON_VMA(!rwsem_is_locked(&vma->vm_mm->mmap_sem), vma); if (pud_trans_huge(*pud) || pud_devmap(*pud)) return __pud_trans_huge_lock(pud, vma); else -- cgit v1.2.3 From ecaad8aca20432fa60821282d8ff479629c9f7b9 Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Tue, 1 Oct 2019 11:17:34 +0200 Subject: mm: Add a walk_page_mapping() function to the pagewalk code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For users that want to travers all page table entries pointing into a region of a struct address_space mapping, introduce a walk_page_mapping() function. The walk_page_mapping() function will be initially be used for dirty- tracking in virtual graphics drivers. Cc: Andrew Morton Cc: Matthew Wilcox Cc: Will Deacon Cc: Peter Zijlstra Cc: Rik van Riel Cc: Minchan Kim Cc: Michal Hocko Cc: Huang Ying Cc: Jérôme Glisse Cc: Kirill A. Shutemov Signed-off-by: Thomas Hellstrom Reviewed-by: Andrew Morton --- include/linux/pagewalk.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h index bddd9759bab9..6ec82e92c87f 100644 --- a/include/linux/pagewalk.h +++ b/include/linux/pagewalk.h @@ -24,6 +24,9 @@ struct mm_walk; * "do page table walk over the current vma", returning * a negative value means "abort current page table walk * right now" and returning 1 means "skip the current vma" + * @pre_vma: if set, called before starting walk on a non-null vma. + * @post_vma: if set, called after a walk on a non-null vma, provided + * that @pre_vma and the vma walk succeeded. */ struct mm_walk_ops { int (*pud_entry)(pud_t *pud, unsigned long addr, @@ -39,6 +42,9 @@ struct mm_walk_ops { struct mm_walk *walk); int (*test_walk)(unsigned long addr, unsigned long next, struct mm_walk *walk); + int (*pre_vma)(unsigned long start, unsigned long end, + struct mm_walk *walk); + void (*post_vma)(struct mm_walk *walk); }; /** @@ -62,5 +68,8 @@ int walk_page_range(struct mm_struct *mm, unsigned long start, void *private); int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops, void *private); +int walk_page_mapping(struct address_space *mapping, pgoff_t first_index, + pgoff_t nr, const struct mm_walk_ops *ops, + void *private); #endif /* _LINUX_PAGEWALK_H */ -- cgit v1.2.3 From c5acad84cf1e33ca1a50984952e1c5b2caa0e13f Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Tue, 19 Mar 2019 13:12:30 +0100 Subject: mm: Add write-protect and clean utilities for address space ranges MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add two utilities to 1) write-protect and 2) clean all ptes pointing into a range of an address space. The utilities are intended to aid in tracking dirty pages (either driver-allocated system memory or pci device memory). The write-protect utility should be used in conjunction with page_mkwrite() and pfn_mkwrite() to trigger write page-faults on page accesses. Typically one would want to use this on sparse accesses into large memory regions. The clean utility should be used to utilize hardware dirtying functionality and avoid the overhead of page-faults, typically on large accesses into small memory regions. Cc: Andrew Morton Cc: Matthew Wilcox Cc: Will Deacon Cc: Peter Zijlstra Cc: Rik van Riel Cc: Minchan Kim Cc: Michal Hocko Cc: Huang Ying Cc: Jérôme Glisse Cc: Kirill A. Shutemov Signed-off-by: Thomas Hellstrom Acked-by: Andrew Morton --- include/linux/mm.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index cc292273e6ba..4bc93477375e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2637,7 +2637,6 @@ typedef int (*pte_fn_t)(pte_t *pte, unsigned long addr, void *data); extern int apply_to_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, pte_fn_t fn, void *data); - #ifdef CONFIG_PAGE_POISONING extern bool page_poisoning_enabled(void); extern void kernel_poison_pages(struct page *page, int numpages, int enable); @@ -2878,5 +2877,17 @@ static inline int pages_identical(struct page *page1, struct page *page2) return !memcmp_pages(page1, page2); } +#ifdef CONFIG_MAPPING_DIRTY_HELPERS +unsigned long clean_record_shared_mapping_range(struct address_space *mapping, + pgoff_t first_index, pgoff_t nr, + pgoff_t bitmap_pgoff, + unsigned long *bitmap, + pgoff_t *start, + pgoff_t *end); + +unsigned long wp_shared_mapping_range(struct address_space *mapping, + pgoff_t first_index, pgoff_t nr); +#endif + #endif /* __KERNEL__ */ #endif /* _LINUX_MM_H */ -- cgit v1.2.3