diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 80 |
1 files changed, 53 insertions, 27 deletions
diff --git a/mm/memory.c b/mm/memory.c index 793004608332..53373b7a1512 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -400,10 +400,17 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table) #endif /* CONFIG_HAVE_RCU_TABLE_FREE */ -/* tlb_gather_mmu - * Called to initialize an (on-stack) mmu_gather structure for page-table - * tear-down from @mm. The @fullmm argument is used when @mm is without - * users and we're going to destroy the full address space (exit/execve). +/** + * tlb_gather_mmu - initialize an mmu_gather structure for page-table tear-down + * @tlb: the mmu_gather structure to initialize + * @mm: the mm_struct of the target address space + * @start: start of the region that will be removed from the page-table + * @end: end of the region that will be removed from the page-table + * + * Called to initialize an (on-stack) mmu_gather structure for page-table + * tear-down from @mm. The @start and @end are set to 0 and -1 + * respectively when @mm is without users and we're going to destroy + * the full address space (exit/execve). */ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end) @@ -2792,8 +2799,37 @@ static inline void unmap_mapping_range_tree(struct rb_root_cached *root, } /** + * unmap_mapping_pages() - Unmap pages from processes. + * @mapping: The address space containing pages to be unmapped. + * @start: Index of first page to be unmapped. + * @nr: Number of pages to be unmapped. 0 to unmap to end of file. + * @even_cows: Whether to unmap even private COWed pages. + * + * Unmap the pages in this address space from any userspace process which + * has them mmaped. Generally, you want to remove COWed pages as well when + * a file is being truncated, but not when invalidating pages from the page + * cache. + */ +void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, + pgoff_t nr, bool even_cows) +{ + struct zap_details details = { }; + + details.check_mapping = even_cows ? NULL : mapping; + details.first_index = start; + details.last_index = start + nr - 1; + if (details.last_index < details.first_index) + details.last_index = ULONG_MAX; + + i_mmap_lock_write(mapping); + if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) + unmap_mapping_range_tree(&mapping->i_mmap, &details); + i_mmap_unlock_write(mapping); +} + +/** * unmap_mapping_range - unmap the portion of all mmaps in the specified - * address_space corresponding to the specified page range in the underlying + * address_space corresponding to the specified byte range in the underlying * file. * * @mapping: the address space containing mmaps to be unmapped. @@ -2811,7 +2847,6 @@ static inline void unmap_mapping_range_tree(struct rb_root_cached *root, void unmap_mapping_range(struct address_space *mapping, loff_t const holebegin, loff_t const holelen, int even_cows) { - struct zap_details details = { }; pgoff_t hba = holebegin >> PAGE_SHIFT; pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; @@ -2823,16 +2858,7 @@ void unmap_mapping_range(struct address_space *mapping, hlen = ULONG_MAX - hba + 1; } - details.check_mapping = even_cows ? NULL : mapping; - details.first_index = hba; - details.last_index = hba + hlen - 1; - if (details.last_index < details.first_index) - details.last_index = ULONG_MAX; - - i_mmap_lock_write(mapping); - if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) - unmap_mapping_range_tree(&mapping->i_mmap, &details); - i_mmap_unlock_write(mapping); + unmap_mapping_pages(mapping, hba, hlen, even_cows); } EXPORT_SYMBOL(unmap_mapping_range); @@ -3485,9 +3511,8 @@ static int fault_around_bytes_get(void *data, u64 *val) } /* - * fault_around_pages() and fault_around_mask() expects fault_around_bytes - * rounded down to nearest page order. It's what do_fault_around() expects to - * see. + * fault_around_bytes must be rounded down to the nearest page order as it's + * what do_fault_around() expects to see. */ static int fault_around_bytes_set(void *data, u64 val) { @@ -3530,13 +3555,14 @@ late_initcall(fault_around_debugfs); * This function doesn't cross the VMA boundaries, in order to call map_pages() * only once. * - * fault_around_pages() defines how many pages we'll try to map. - * do_fault_around() expects it to return a power of two less than or equal to - * PTRS_PER_PTE. + * fault_around_bytes defines how many bytes we'll try to map. + * do_fault_around() expects it to be set to a power of two less than or equal + * to PTRS_PER_PTE. * - * The virtual address of the area that we map is naturally aligned to the - * fault_around_pages() value (and therefore to page order). This way it's - * easier to guarantee that we don't cross page table boundaries. + * The virtual address of the area that we map is naturally aligned to + * fault_around_bytes rounded down to the machine page size + * (and therefore to page order). This way it's easier to guarantee + * that we don't cross page table boundaries. */ static int do_fault_around(struct vm_fault *vmf) { @@ -3553,8 +3579,8 @@ static int do_fault_around(struct vm_fault *vmf) start_pgoff -= off; /* - * end_pgoff is either end of page table or end of vma - * or fault_around_pages() from start_pgoff, depending what is nearest. + * end_pgoff is either the end of the page table, the end of + * the vma or nr_pages from start_pgoff, depending what is nearest. */ end_pgoff = start_pgoff - ((vmf->address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + |