[PATCH] Simplify migrate_page_add
Simplify migrate_page_add after feedback from Hugh. This also allows us to
drop one parameter from migrate_page_add.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 551cde4..a683a66 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -185,8 +185,8 @@
}
static void gather_stats(struct page *, void *);
-static void migrate_page_add(struct vm_area_struct *vma,
- struct page *page, struct list_head *pagelist, unsigned long flags);
+static void migrate_page_add(struct page *page, struct list_head *pagelist,
+ unsigned long flags);
/* Scan through pages checking if pages follow certain conditions. */
static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
@@ -228,7 +228,7 @@
if (flags & MPOL_MF_STATS)
gather_stats(page, private);
else if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
- migrate_page_add(vma, page, private, flags);
+ migrate_page_add(page, private, flags);
else
break;
} while (pte++, addr += PAGE_SIZE, addr != end);
@@ -531,42 +531,13 @@
* page migration
*/
-/* Check if we are the only process mapping the page in question */
-static inline int single_mm_mapping(struct mm_struct *mm,
- struct address_space *mapping)
-{
- struct vm_area_struct *vma;
- struct prio_tree_iter iter;
- int rc = 1;
-
- spin_lock(&mapping->i_mmap_lock);
- vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
- if (mm != vma->vm_mm) {
- rc = 0;
- goto out;
- }
- list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
- if (mm != vma->vm_mm) {
- rc = 0;
- goto out;
- }
-out:
- spin_unlock(&mapping->i_mmap_lock);
- return rc;
-}
-
-/*
- * Add a page to be migrated to the pagelist
- */
-static void migrate_page_add(struct vm_area_struct *vma,
- struct page *page, struct list_head *pagelist, unsigned long flags)
+static void migrate_page_add(struct page *page, struct list_head *pagelist,
+ unsigned long flags)
{
/*
- * Avoid migrating a page that is shared by others and not writable.
+ * Avoid migrating a page that is shared with others.
*/
- if ((flags & MPOL_MF_MOVE_ALL) || !page->mapping || PageAnon(page) ||
- mapping_writably_mapped(page->mapping) ||
- single_mm_mapping(vma->vm_mm, page->mapping)) {
+ if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
if (isolate_lru_page(page))
list_add(&page->lru, pagelist);
}