mm: CONFIG_MMU for PG_mlocked

Remove three degrees of obfuscation, left over from when we had
CONFIG_UNEVICTABLE_LRU.  MLOCK_PAGES is CONFIG_HAVE_MLOCKED_PAGE_BIT is
CONFIG_HAVE_MLOCK is CONFIG_MMU.  rmap.o (and memory-failure.o) are only
built when CONFIG_MMU, so don't need such conditions at all.

Somehow, I feel no compulsion to remove the CONFIG_HAVE_MLOCK* lines from
169 defconfigs: leave those to evolve in due course.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 11 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index c3d6dc4223a..eb3dfc8355e 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -788,7 +788,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
                         ret = SWAP_MLOCK;
                         goto out_unmap;
                 }
-                if (MLOCK_PAGES && TTU_ACTION(flags) == TTU_MUNLOCK)
+                if (TTU_ACTION(flags) == TTU_MUNLOCK)
                         goto out_unmap;
         }
         if (!(flags & TTU_IGNORE_ACCESS)) {
@@ -861,7 +861,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 out_unmap:
         pte_unmap_unlock(pte, ptl);
 
-        if (MLOCK_PAGES && ret == SWAP_MLOCK) {
+        if (ret == SWAP_MLOCK) {
                 ret = SWAP_AGAIN;
                 if (down_read_trylock(&vma->vm_mm->mmap_sem)) {
                         if (vma->vm_flags & VM_LOCKED) {
@@ -938,11 +938,10 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
                 return ret;
 
         /*
-         * MLOCK_PAGES => feature is configured.
-         * if we can acquire the mmap_sem for read, and vma is VM_LOCKED,
+         * If we can acquire the mmap_sem for read, and vma is VM_LOCKED,
          * keep the sem while scanning the cluster for mlocking pages.
          */
-        if (MLOCK_PAGES && down_read_trylock(&vma->vm_mm->mmap_sem)) {
+        if (down_read_trylock(&vma->vm_mm->mmap_sem)) {
                 locked_vma = (vma->vm_flags & VM_LOCKED);
                 if (!locked_vma)
                         up_read(&vma->vm_mm->mmap_sem); /* don't need it */
@@ -1075,9 +1074,6 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
 
         list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
                                                 shared.vm_set.list) {
-                if (!MLOCK_PAGES && !(flags & TTU_IGNORE_MLOCK) &&
-                        (vma->vm_flags & VM_LOCKED))
-                        continue;
                 cursor = (unsigned long) vma->vm_private_data;
                 if (cursor > max_nl_cursor)
                         max_nl_cursor = cursor;
@@ -1110,9 +1106,6 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
         do {
                 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
                                                 shared.vm_set.list) {
-                        if (!MLOCK_PAGES && !(flags & TTU_IGNORE_MLOCK) &&
-                            (vma->vm_flags & VM_LOCKED))
-                                continue;
                         cursor = (unsigned long) vma->vm_private_data;
                         while ( cursor < max_nl_cursor &&
                                 cursor < vma->vm_end - vma->vm_start) {