1 files changed, 12 insertions, 3 deletions

diff --git a/mm/mlock.c b/mm/mlock.c
index 048260c4e02e..4f4f53bdc65d 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -14,7 +14,7 @@
 #include <linux/mempolicy.h>
 #include <linux/syscalls.h>
 #include <linux/sched.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/rmap.h>
 #include <linux/mmzone.h>
 #include <linux/hugetlb.h>
@@ -110,7 +110,15 @@ void munlock_vma_page(struct page *page)
         if (TestClearPageMlocked(page)) {
                 dec_zone_page_state(page, NR_MLOCK);
                 if (!isolate_lru_page(page)) {
-                        int ret = try_to_munlock(page);
+                        int ret = SWAP_AGAIN;
+
+                        /*
+                         * Optimization: if the page was mapped just once,
+                         * that's our mapping and we don't need to check all the
+                         * other vmas.
+                         */
+                        if (page_mapcount(page) > 1)
+                                ret = try_to_munlock(page);
                         /*
                          * did try_to_unlock() succeed or punt?
                          */
@@ -549,7 +557,8 @@ 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);