X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Frmap.c;h=dfbb89f99a15a610b9463ea84a35068712187d23;hb=7b8631b53bea286b68847a939b87135198335b66;hp=914d04b98beee0aca9e52eada3b52db6307c7b30;hpb=dad2ad82c5f058367df79de022bd12d36afcd065;p=linux-2.6 diff --git a/mm/rmap.c b/mm/rmap.c index 914d04b98b..dfbb89f99a 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -20,13 +20,13 @@ /* * Lock ordering in mm: * - * inode->i_sem (while writing or truncating, not reading or faulting) + * inode->i_mutex (while writing or truncating, not reading or faulting) * inode->i_alloc_sem * * When a page fault occurs in writing from user to file, down_read - * of mmap_sem nests within i_sem; in sys_msync, i_sem nests within - * down_read of mmap_sem; i_sem and down_write of mmap_sem are never - * taken together; in truncation, i_sem is taken outermost. + * of mmap_sem nests within i_mutex; in sys_msync, i_mutex nests within + * down_read of mmap_sem; i_mutex and down_write of mmap_sem are never + * taken together; in truncation, i_mutex is taken outermost. * * mm->mmap_sem * page->flags PG_locked (lock_page) @@ -225,7 +225,7 @@ vma_address(struct page *page, struct vm_area_struct *vma) /* * At what user virtual address is page expected in vma? checking that the - * page matches the vma: currently only used by unuse_process, on anon pages. + * page matches the vma: currently only used on anon pages, by unuse_vma; */ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) { @@ -234,7 +234,8 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) (void *)page->mapping - PAGE_MAPPING_ANON) return -EFAULT; } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { - if (vma->vm_file->f_mapping != page->mapping) + if (!vma->vm_file || + vma->vm_file->f_mapping != page->mapping) return -EFAULT; } else return -EFAULT; @@ -289,7 +290,7 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm, * repeatedly from either page_referenced_anon or page_referenced_file. */ static int page_referenced_one(struct page *page, - struct vm_area_struct *vma, unsigned int *mapcount, int ignore_token) + struct vm_area_struct *vma, unsigned int *mapcount) { struct mm_struct *mm = vma->vm_mm; unsigned long address; @@ -310,7 +311,7 @@ static int page_referenced_one(struct page *page, /* Pretend the page is referenced if the task has the swap token and is in the middle of a page fault. */ - if (mm != current->mm && !ignore_token && has_swap_token(mm) && + if (mm != current->mm && has_swap_token(mm) && rwsem_is_locked(&mm->mmap_sem)) referenced++; @@ -320,7 +321,7 @@ out: return referenced; } -static int page_referenced_anon(struct page *page, int ignore_token) +static int page_referenced_anon(struct page *page) { unsigned int mapcount; struct anon_vma *anon_vma; @@ -333,8 +334,7 @@ static int page_referenced_anon(struct page *page, int ignore_token) mapcount = page_mapcount(page); list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { - referenced += page_referenced_one(page, vma, &mapcount, - ignore_token); + referenced += page_referenced_one(page, vma, &mapcount); if (!mapcount) break; } @@ -353,7 +353,7 @@ static int page_referenced_anon(struct page *page, int ignore_token) * * This function is only called from page_referenced for object-based pages. */ -static int page_referenced_file(struct page *page, int ignore_token) +static int page_referenced_file(struct page *page) { unsigned int mapcount; struct address_space *mapping = page->mapping; @@ -391,8 +391,7 @@ static int page_referenced_file(struct page *page, int ignore_token) referenced++; break; } - referenced += page_referenced_one(page, vma, &mapcount, - ignore_token); + referenced += page_referenced_one(page, vma, &mapcount); if (!mapcount) break; } @@ -409,13 +408,10 @@ static int page_referenced_file(struct page *page, int ignore_token) * Quick test_and_clear_referenced for all mappings to a page, * returns the number of ptes which referenced the page. */ -int page_referenced(struct page *page, int is_locked, int ignore_token) +int page_referenced(struct page *page, int is_locked) { int referenced = 0; - if (!swap_token_default_timeout) - ignore_token = 1; - if (page_test_and_clear_young(page)) referenced++; @@ -424,21 +420,44 @@ int page_referenced(struct page *page, int is_locked, int ignore_token) if (page_mapped(page) && page->mapping) { if (PageAnon(page)) - referenced += page_referenced_anon(page, ignore_token); + referenced += page_referenced_anon(page); else if (is_locked) - referenced += page_referenced_file(page, ignore_token); + referenced += page_referenced_file(page); else if (TestSetPageLocked(page)) referenced++; else { if (page->mapping) - referenced += page_referenced_file(page, - ignore_token); + referenced += page_referenced_file(page); unlock_page(page); } } return referenced; } +/** + * page_set_anon_rmap - setup new anonymous rmap + * @page: the page to add the mapping to + * @vma: the vm area in which the mapping is added + * @address: the user virtual address mapped + */ +static void __page_set_anon_rmap(struct page *page, + struct vm_area_struct *vma, unsigned long address) +{ + struct anon_vma *anon_vma = vma->anon_vma; + + BUG_ON(!anon_vma); + anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; + page->mapping = (struct address_space *) anon_vma; + + page->index = linear_page_index(vma, address); + + /* + * nr_mapped state can be updated without turning off + * interrupts because it is not modified via interrupt. + */ + __inc_page_state(nr_mapped); +} + /** * page_add_anon_rmap - add pte mapping to an anonymous page * @page: the page to add the mapping to @@ -450,20 +469,27 @@ int page_referenced(struct page *page, int is_locked, int ignore_token) void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) { - if (atomic_inc_and_test(&page->_mapcount)) { - struct anon_vma *anon_vma = vma->anon_vma; - - BUG_ON(!anon_vma); - anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; - page->mapping = (struct address_space *) anon_vma; - - page->index = linear_page_index(vma, address); - - inc_page_state(nr_mapped); - } + if (atomic_inc_and_test(&page->_mapcount)) + __page_set_anon_rmap(page, vma, address); /* else checking page index and mapping is racy */ } +/* + * page_add_new_anon_rmap - add pte mapping to a new anonymous page + * @page: the page to add the mapping to + * @vma: the vm area in which the mapping is added + * @address: the user virtual address mapped + * + * Same as page_add_anon_rmap but must only be called on *new* pages. + * This means the inc-and-test can be bypassed. + */ +void page_add_new_anon_rmap(struct page *page, + struct vm_area_struct *vma, unsigned long address) +{ + atomic_set(&page->_mapcount, 0); /* elevate count by 1 (starts at -1) */ + __page_set_anon_rmap(page, vma, address); +} + /** * page_add_file_rmap - add pte mapping to a file page * @page: the page to add the mapping to @@ -476,7 +502,7 @@ void page_add_file_rmap(struct page *page) BUG_ON(!pfn_valid(page_to_pfn(page))); if (atomic_inc_and_test(&page->_mapcount)) - inc_page_state(nr_mapped); + __inc_page_state(nr_mapped); } /** @@ -488,6 +514,13 @@ void page_add_file_rmap(struct page *page) void page_remove_rmap(struct page *page) { if (atomic_add_negative(-1, &page->_mapcount)) { + if (page_mapcount(page) < 0) { + printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page)); + printk (KERN_EMERG " page->flags = %lx\n", page->flags); + printk (KERN_EMERG " page->count = %x\n", page_count(page)); + printk (KERN_EMERG " page->mapping = %p\n", page->mapping); + } + BUG_ON(page_mapcount(page) < 0); /* * It would be tidy to reset the PageAnon mapping here, @@ -500,7 +533,7 @@ void page_remove_rmap(struct page *page) */ if (page_test_and_clear_dirty(page)) set_page_dirty(page); - dec_page_state(nr_mapped); + __dec_page_state(nr_mapped); } } @@ -529,10 +562,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma) * If the page is mlock()d, we cannot swap it out. * If it's recently referenced (perhaps page_referenced * skipped over this mm) then we should reactivate it. - * - * Pages belonging to VM_RESERVED regions should not happen here. */ - if ((vma->vm_flags & (VM_LOCKED|VM_RESERVED)) || + if ((vma->vm_flags & VM_LOCKED) || ptep_clear_flush_young(vma, address, pte)) { ret = SWAP_FAIL; goto out_unmap; @@ -613,7 +644,6 @@ static void try_to_unmap_cluster(unsigned long cursor, struct page *page; unsigned long address; unsigned long end; - unsigned long pfn; address = (vma->vm_start + cursor) & CLUSTER_MASK; end = address + CLUSTER_SIZE; @@ -642,21 +672,14 @@ static void try_to_unmap_cluster(unsigned long cursor, for (; address < end; pte++, address += PAGE_SIZE) { if (!pte_present(*pte)) continue; - - pfn = pte_pfn(*pte); - if (unlikely(!pfn_valid(pfn))) { - print_bad_pte(vma, *pte, address); - continue; - } - - page = pfn_to_page(pfn); - BUG_ON(PageAnon(page)); + page = vm_normal_page(vma, address, *pte); + BUG_ON(!page || PageAnon(page)); if (ptep_clear_flush_young(vma, address, pte)) continue; /* Nuke the page table entry. */ - flush_cache_page(vma, address, pfn); + flush_cache_page(vma, address, pte_pfn(*pte)); pteval = ptep_clear_flush(vma, address, pte); /* If nonlinear, store the file page offset in the pte. */ @@ -727,7 +750,7 @@ static int try_to_unmap_file(struct page *page) list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) { - if (vma->vm_flags & (VM_LOCKED|VM_RESERVED)) + if (vma->vm_flags & VM_LOCKED) continue; cursor = (unsigned long) vma->vm_private_data; if (cursor > max_nl_cursor) @@ -761,7 +784,7 @@ static int try_to_unmap_file(struct page *page) do { list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) { - if (vma->vm_flags & (VM_LOCKED|VM_RESERVED)) + if (vma->vm_flags & VM_LOCKED) continue; cursor = (unsigned long) vma->vm_private_data; while ( cursor < max_nl_cursor && @@ -783,11 +806,8 @@ static int try_to_unmap_file(struct page *page) * in locked vmas). Reset cursor on all unreserved nonlinear * vmas, now forgetting on which ones it had fallen behind. */ - list_for_each_entry(vma, &mapping->i_mmap_nonlinear, - shared.vm_set.list) { - if (!(vma->vm_flags & VM_RESERVED)) - vma->vm_private_data = NULL; - } + list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) + vma->vm_private_data = NULL; out: spin_unlock(&mapping->i_mmap_lock); return ret;