diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 77 |
1 files changed, 61 insertions, 16 deletions
diff --git a/mm/memory.c b/mm/memory.c index 109e9866237..92a3ebd8d79 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -49,6 +49,7 @@ #include <linux/module.h> #include <linux/delayacct.h> #include <linux/init.h> +#include <linux/writeback.h> #include <asm/pgalloc.h> #include <asm/uaccess.h> @@ -1226,7 +1227,12 @@ out: return retval; } -/* +/** + * vm_insert_page - insert single page into user vma + * @vma: user vma to map to + * @addr: target user address of this page + * @page: source kernel page + * * This allows drivers to insert individual pages they've allocated * into a user vma. * @@ -1318,7 +1324,16 @@ static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, return 0; } -/* Note: this is only safe if the mm semaphore is held when called. */ +/** + * remap_pfn_range - remap kernel memory to userspace + * @vma: user vma to map to + * @addr: target user address to start at + * @pfn: physical address of kernel memory + * @size: size of map area + * @prot: page protection flags for this mapping + * + * Note: this is only safe if the mm semaphore is held when called. + */ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn, unsigned long size, pgprot_t prot) { @@ -1458,14 +1473,29 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, { struct page *old_page, *new_page; pte_t entry; - int reuse, ret = VM_FAULT_MINOR; + int reuse = 0, ret = VM_FAULT_MINOR; + struct page *dirty_page = NULL; old_page = vm_normal_page(vma, address, orig_pte); if (!old_page) goto gotten; - if (unlikely((vma->vm_flags & (VM_SHARED|VM_WRITE)) == - (VM_SHARED|VM_WRITE))) { + /* + * Take out anonymous pages first, anonymous shared vmas are + * not dirty accountable. + */ + if (PageAnon(old_page)) { + if (!TestSetPageLocked(old_page)) { + reuse = can_share_swap_page(old_page); + unlock_page(old_page); + } + } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == + (VM_WRITE|VM_SHARED))) { + /* + * Only catch write-faults on shared writable pages, + * read-only shared pages can get COWed by + * get_user_pages(.write=1, .force=1). + */ if (vma->vm_ops && vma->vm_ops->page_mkwrite) { /* * Notify the address space that the page is about to @@ -1494,13 +1524,9 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, if (!pte_same(*page_table, orig_pte)) goto unlock; } - + dirty_page = old_page; + get_page(dirty_page); reuse = 1; - } else if (PageAnon(old_page) && !TestSetPageLocked(old_page)) { - reuse = can_share_swap_page(old_page); - unlock_page(old_page); - } else { - reuse = 0; } if (reuse) { @@ -1566,6 +1592,10 @@ gotten: page_cache_release(old_page); unlock: pte_unmap_unlock(page_table, ptl); + if (dirty_page) { + set_page_dirty_balance(dirty_page); + put_page(dirty_page); + } return ret; oom: if (old_page) @@ -1785,9 +1815,10 @@ void unmap_mapping_range(struct address_space *mapping, } EXPORT_SYMBOL(unmap_mapping_range); -/* - * Handle all mappings that got truncated by a "truncate()" - * system call. +/** + * vmtruncate - unmap mappings "freed" by truncate() syscall + * @inode: inode of the file used + * @offset: file offset to start truncating * * NOTE! We have to be ready to update the memory sharing * between the file and the memory map for a potential last @@ -1856,11 +1887,16 @@ int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) } EXPORT_UNUSED_SYMBOL(vmtruncate_range); /* June 2006 */ -/* +/** + * swapin_readahead - swap in pages in hope we need them soon + * @entry: swap entry of this memory + * @addr: address to start + * @vma: user vma this addresses belong to + * * Primitive swap readahead code. We simply read an aligned block of * (1 << page_cluster) entries in the swap area. This method is chosen * because it doesn't cost us any seek time. We also make sure to queue - * the 'original' request together with the readahead ones... + * the 'original' request together with the readahead ones... * * This has been extended to use the NUMA policies from the mm triggering * the readahead. @@ -2098,6 +2134,7 @@ static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned int sequence = 0; int ret = VM_FAULT_MINOR; int anon = 0; + struct page *dirty_page = NULL; pte_unmap(page_table); BUG_ON(vma->vm_flags & VM_PFNMAP); @@ -2192,6 +2229,10 @@ retry: } else { inc_mm_counter(mm, file_rss); page_add_file_rmap(new_page); + if (write_access) { + dirty_page = new_page; + get_page(dirty_page); + } } } else { /* One of our sibling threads was faster, back out. */ @@ -2204,6 +2245,10 @@ retry: lazy_mmu_prot_update(entry); unlock: pte_unmap_unlock(page_table, ptl); + if (dirty_page) { + set_page_dirty_balance(dirty_page); + put_page(dirty_page); + } return ret; oom: page_cache_release(new_page); |