Merge branch 'clockevents/fixes' of git://git.linaro.org/people/daniel.lezcano/linux...

[linux-drm-fsl-dcu.git] / mm / migrate.c

diff --git a/mm/migrate.c b/mm/migrate.c
index 316e720a2023c260b0205cdd2cd6be7d257986ac..bb940045fe8595842ed58f2e32f87b83d40485e1 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -441,6 +441,54 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
        return MIGRATEPAGE_SUCCESS;
 }
 
+/*
+ * Gigantic pages are so large that we do not guarantee that page++ pointer
+ * arithmetic will work across the entire page.  We need something more
+ * specialized.
+ */
+static void __copy_gigantic_page(struct page *dst, struct page *src,
+                               int nr_pages)
+{
+       int i;
+       struct page *dst_base = dst;
+       struct page *src_base = src;
+
+       for (i = 0; i < nr_pages; ) {
+               cond_resched();
+               copy_highpage(dst, src);
+
+               i++;
+               dst = mem_map_next(dst, dst_base, i);
+               src = mem_map_next(src, src_base, i);
+       }
+}
+
+static void copy_huge_page(struct page *dst, struct page *src)
+{
+       int i;
+       int nr_pages;
+
+       if (PageHuge(src)) {
+               /* hugetlbfs page */
+               struct hstate *h = page_hstate(src);
+               nr_pages = pages_per_huge_page(h);
+
+               if (unlikely(nr_pages > MAX_ORDER_NR_PAGES)) {
+                       __copy_gigantic_page(dst, src, nr_pages);
+                       return;
+               }
+       } else {
+               /* thp page */
+               BUG_ON(!PageTransHuge(src));
+               nr_pages = hpage_nr_pages(src);
+       }
+
+       for (i = 0; i < nr_pages; i++) {
+               cond_resched();
+               copy_highpage(dst + i, src + i);
+       }
+}
+
 /*
  * Copy the page to its new location
  */