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yaml --- r: 230825 b: refs/heads/master c: 2919bfd h: refs/heads/master i: 230823: fa216e8 v: v3
git-mirror · Jan 14, 2011 · f14f3ac · f14f3ac
1 parent 2076d0c
commit f14f3ac
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 73ae31e5986a4c0ee84bfd13ccd9b57a98956f6f
+refs/heads/master: 2919bfd0758257c469abef8c26c3e516bbebb851
diff --git a/trunk/mm/ksm.c b/trunk/mm/ksm.c
@@ -1296,6 +1296,18 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
 
 	slot = ksm_scan.mm_slot;
 	if (slot == &ksm_mm_head) {
+		/*
+		 * A number of pages can hang around indefinitely on per-cpu
+		 * pagevecs, raised page count preventing write_protect_page
+		 * from merging them.  Though it doesn't really matter much,
+		 * it is puzzling to see some stuck in pages_volatile until
+		 * other activity jostles them out, and they also prevented
+		 * LTP's KSM test from succeeding deterministically; so drain
+		 * them here (here rather than on entry to ksm_do_scan(),
+		 * so we don't IPI too often when pages_to_scan is set low).
+		 */
+		lru_add_drain_all();
+
 		root_unstable_tree = RB_ROOT;
 
 		spin_lock(&ksm_mmlist_lock);