mm: do not drain pagevecs for mlockall(MCL_FUTURE)

MCL_FUTURE does not move pages between lru list and draining the LRU per cpu pagevecs is a nasty activity. Avoid doing it unecessarily. Signed-off-by: Christoph Lameter <[email protected]> Cc: David Rientjes <[email protected]> Reviewed-by: Minchan Kim <[email protected]> Acked-by: KOSAKI Motohiro <[email protected]> Cc: Mel Gorman <[email protected]> Acked-by: Johannes Weiner <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
mna · Nov 1, 2011 · df9d698 · df9d698
1 parent e0c2327
commit df9d698
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/mm/mlock.c b/mm/mlock.c
@@ -549,7 +549,8 @@ SYSCALL_DEFINE1(mlockall, int, flags)
 	if (!can_do_mlock())
 		goto out;
 
-	lru_add_drain_all();	/* flush pagevec */
+	if (flags & MCL_CURRENT)
+		lru_add_drain_all();	/* flush pagevec */
 
 	down_write(&current->mm->mmap_sem);