Two callbacks to remove individual pages as done in rmap code

	invalidate_page()

Called from the inner loop of rmap walks to invalidate pages.

	age_page()

Called for the determination of the page referenced status.

If we do not care about page referenced status then an age_page callback
may be be omitted. PageLock and pte lock are held when either of the
functions is called.

Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
 mm/rmap.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

Index: linux-2.6/mm/rmap.c
===================================================================
--- linux-2.6.orig/mm/rmap.c	2008-02-07 16:49:32.000000000 -0800
+++ linux-2.6/mm/rmap.c	2008-02-07 17:25:25.000000000 -0800
@@ -49,6 +49,7 @@
 #include <linux/module.h>
 #include <linux/kallsyms.h>
 #include <linux/memcontrol.h>
+#include <linux/mmu_notifier.h>
 
 #include <asm/tlbflush.h>
 
@@ -287,7 +288,8 @@ static int page_referenced_one(struct pa
 	if (vma->vm_flags & VM_LOCKED) {
 		referenced++;
 		*mapcount = 1;	/* break early from loop */
-	} else if (ptep_clear_flush_young(vma, address, pte))
+	} else if (ptep_clear_flush_young(vma, address, pte) |
+		   mmu_notifier_age_page(mm, address))
 		referenced++;
 
 	/* Pretend the page is referenced if the task has the
@@ -455,6 +457,7 @@ static int page_mkclean_one(struct page 
 
 		flush_cache_page(vma, address, pte_pfn(*pte));
 		entry = ptep_clear_flush(vma, address, pte);
+		mmu_notifier(invalidate_page, mm, address);
 		entry = pte_wrprotect(entry);
 		entry = pte_mkclean(entry);
 		set_pte_at(mm, address, pte, entry);
@@ -712,7 +715,8 @@ static int try_to_unmap_one(struct page 
 	 * skipped over this mm) then we should reactivate it.
 	 */
 	if (!migration && ((vma->vm_flags & VM_LOCKED) ||
-			(ptep_clear_flush_young(vma, address, pte)))) {
+			(ptep_clear_flush_young(vma, address, pte) |
+				mmu_notifier_age_page(mm, address)))) {
 		ret = SWAP_FAIL;
 		goto out_unmap;
 	}
@@ -720,6 +724,7 @@ static int try_to_unmap_one(struct page 
 	/* Nuke the page table entry. */
 	flush_cache_page(vma, address, page_to_pfn(page));
 	pteval = ptep_clear_flush(vma, address, pte);
+	mmu_notifier(invalidate_page, mm, address);
 
 	/* Move the dirty bit to the physical page now the pte is gone. */
 	if (pte_dirty(pteval))
@@ -844,12 +849,14 @@ static void try_to_unmap_cluster(unsigne
 		page = vm_normal_page(vma, address, *pte);
 		BUG_ON(!page || PageAnon(page));
 
-		if (ptep_clear_flush_young(vma, address, pte))
+		if (ptep_clear_flush_young(vma, address, pte) |
+		    mmu_notifier_age_page(mm, address))
 			continue;
 
 		/* Nuke the page table entry. */
 		flush_cache_page(vma, address, pte_pfn(*pte));
 		pteval = ptep_clear_flush(vma, address, pte);
+		mmu_notifier(invalidate_page, mm, address);
 
 		/* If nonlinear, store the file page offset in the pte. */
 		if (page->index != linear_page_index(vma, address))

-- 

