thp: skip transhuge pages in ksm for now

Skip transhuge pages in ksm for now. Signed-off-by: Andrea Arcangeli <[email protected]> Reviewed-by: Rik van Riel <[email protected]> Acked-by: Mel Gorman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
mgowda · Jan 14, 2011 · 21ae5b0 · 21ae5b0
1 parent b15d00b
commit 21ae5b0
Showing 1 changed file with 15 additions and 4 deletions.
diff --git a/mm/ksm.c b/mm/ksm.c
@@ -430,7 +430,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 	page = follow_page(vma, addr, FOLL_GET);
 	if (IS_ERR_OR_NULL(page))
 		goto out;
-	if (PageAnon(page)) {
+	if (PageAnon(page) && !PageTransCompound(page)) {
 		flush_anon_page(vma, page, addr);
 		flush_dcache_page(page);
 	} else {
@@ -1279,7 +1279,19 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
 			if (ksm_test_exit(mm))
 				break;
 			*page = follow_page(vma, ksm_scan.address, FOLL_GET);
-			if (!IS_ERR_OR_NULL(*page) && PageAnon(*page)) {
+			if (IS_ERR_OR_NULL(*page)) {
+				ksm_scan.address += PAGE_SIZE;
+				cond_resched();
+				continue;
+			}
+			if (PageTransCompound(*page)) {
+				put_page(*page);
+				ksm_scan.address &= HPAGE_PMD_MASK;
+				ksm_scan.address += HPAGE_PMD_SIZE;
+				cond_resched();
+				continue;
+			}
+			if (PageAnon(*page)) {
 				flush_anon_page(vma, *page, ksm_scan.address);
 				flush_dcache_page(*page);
 				rmap_item = get_next_rmap_item(slot,
@@ -1293,8 +1305,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
 				up_read(&mm->mmap_sem);
 				return rmap_item;
 			}
-			if (!IS_ERR_OR_NULL(*page))
-				put_page(*page);
+			put_page(*page);
 			ksm_scan.address += PAGE_SIZE;
 			cond_resched();
 		}