2 files changed, 26 insertions, 42 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index d49736ff8a8d..a65efd4db3e1 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -122,9 +122,17 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
                 return 0;
 
         if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
-                unsigned long n;
+                free = global_page_state(NR_FREE_PAGES);
+                free += global_page_state(NR_FILE_PAGES);
+
+                /*
+                 * shmem pages shouldn't be counted as free in this
+                 * case, they can't be purged, only swapped out, and
+                 * that won't affect the overall amount of available
+                 * memory in the system.
+                 */
+                free -= global_page_state(NR_SHMEM);
 
-                free = global_page_state(NR_FILE_PAGES);
                 free += nr_swap_pages;
 
                 /*
@@ -136,34 +144,18 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
                 free += global_page_state(NR_SLAB_RECLAIMABLE);
 
                 /*
-                 * Leave the last 3% for root
-                 */
-                if (!cap_sys_admin)
-                        free -= free / 32;
-
-                if (free > pages)
-                        return 0;
-
-                /*
-                 * nr_free_pages() is very expensive on large systems,
-                 * only call if we're about to fail.
-                 */
-                n = nr_free_pages();
-
-                /*
                  * Leave reserved pages. The pages are not for anonymous pages.
                  */
-                if (n <= totalreserve_pages)
+                if (free <= totalreserve_pages)
                         goto error;
                 else
-                        n -= totalreserve_pages;
+                        free -= totalreserve_pages;
 
                 /*
                  * Leave the last 3% for root
                  */
                 if (!cap_sys_admin)
-                        n -= n / 32;
-                free += n;
+                        free -= free / 32;
 
                 if (free > pages)
                         return 0;
diff --git a/mm/nommu.c b/mm/nommu.c
index 5c5c2d4b1807..4358032566e9 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1884,9 +1884,17 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
                 return 0;
 
         if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
-                unsigned long n;
+                free = global_page_state(NR_FREE_PAGES);
+                free += global_page_state(NR_FILE_PAGES);
+
+                /*
+                 * shmem pages shouldn't be counted as free in this
+                 * case, they can't be purged, only swapped out, and
+                 * that won't affect the overall amount of available
+                 * memory in the system.
+                 */
+                free -= global_page_state(NR_SHMEM);
 
-                free = global_page_state(NR_FILE_PAGES);
                 free += nr_swap_pages;
 
                 /*
@@ -1898,34 +1906,18 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
                 free += global_page_state(NR_SLAB_RECLAIMABLE);
 
                 /*
-                 * Leave the last 3% for root
-                 */
-                if (!cap_sys_admin)
-                        free -= free / 32;
-
-                if (free > pages)
-                        return 0;
-
-                /*
-                 * nr_free_pages() is very expensive on large systems,
-                 * only call if we're about to fail.
-                 */
-                n = nr_free_pages();
-
-                /*
                  * Leave reserved pages. The pages are not for anonymous pages.
                  */
-                if (n <= totalreserve_pages)
+                if (free <= totalreserve_pages)
                         goto error;
                 else
-                        n -= totalreserve_pages;
+                        free -= totalreserve_pages;
 
                 /*
                  * Leave the last 3% for root
                  */
                 if (!cap_sys_admin)
-                        n -= n / 32;
-                free += n;
+                        free -= free / 32;
 
                 if (free > pages)
                         return 0;