diff options
Diffstat (limited to 'mm/ksm.c')
| -rw-r--r-- | mm/ksm.c | 20 |
1 files changed, 17 insertions, 3 deletions
@@ -1052,8 +1052,13 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page, * So we clear the pte and flush the tlb before the check * this assure us that no O_DIRECT can happen after the check * or in the middle of the check. + * + * No need to notify as we are downgrading page table to read + * only not changing it to point to a new page. + * + * See Documentation/vm/mmu_notifier.txt */ - entry = ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte); + entry = ptep_clear_flush(vma, pvmw.address, pvmw.pte); /* * Check that no O_DIRECT or similar I/O is in progress on the * page @@ -1136,7 +1141,13 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, } flush_cache_page(vma, addr, pte_pfn(*ptep)); - ptep_clear_flush_notify(vma, addr, ptep); + /* + * No need to notify as we are replacing a read only page with another + * read only page with the same content. + * + * See Documentation/vm/mmu_notifier.txt + */ + ptep_clear_flush(vma, addr, ptep); set_pte_at_notify(mm, addr, ptep, newpte); page_remove_rmap(page, false); @@ -1990,6 +2001,7 @@ static void stable_tree_append(struct rmap_item *rmap_item, */ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item) { + struct mm_struct *mm = rmap_item->mm; struct rmap_item *tree_rmap_item; struct page *tree_page = NULL; struct stable_node *stable_node; @@ -2062,9 +2074,11 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item) if (ksm_use_zero_pages && (checksum == zero_checksum)) { struct vm_area_struct *vma; - vma = find_mergeable_vma(rmap_item->mm, rmap_item->address); + down_read(&mm->mmap_sem); + vma = find_mergeable_vma(mm, rmap_item->address); err = try_to_merge_one_page(vma, page, ZERO_PAGE(rmap_item->address)); + up_read(&mm->mmap_sem); /* * In case of failure, the page was not really empty, so we * need to continue. Otherwise we're done. |