thp: ksm: free swap when swapcache page is replaced

When a swapcache page is replaced by a ksm page, it's best to free that swap immediately. Reported-by: Andrea Arcangeli <[email protected]> Signed-off-by: Hugh Dickins <[email protected]> Signed-off-by: Andrea Arcangeli <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
csanz · Jan 14, 2011 · ae52a2a · ae52a2a
1 parent 240c879
commit ae52a2a
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/mm/ksm.c b/mm/ksm.c
@@ -800,6 +800,8 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
 	set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot));
 
 	page_remove_rmap(page);
+	if (!page_mapped(page))
+		try_to_free_swap(page);
 	put_page(page);
 
 	pte_unmap_unlock(ptep, ptl);