[PATCH] [RFC] mm: non linear mapping page don't mark as PG_mlocked

[KOSAKI Motohiro]

Now, try_to_unmap_file() lost the capability to treat VM_NONLINEAR.
Then, mlock() shouldn't mark the page of non linear mapping as
PG_mlocked. Otherwise the page continue to drinker walk between
evictable and unevictable lru.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
---
 mm/mlock.c |   37 +++++++++++++++++++++++--------------
 1 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 48691fb..4187f9c 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -266,25 +266,34 @@ long mlock_vma_pages_range(struct vm_area_struct *vma,
 	if (vma->vm_flags & (VM_IO | VM_PFNMAP))
 		goto no_mlock;
 
-	if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) ||
+	if ((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) ||
 			is_vm_hugetlb_page(vma) ||
-			vma == get_gate_vma(current))) {
+			vma == get_gate_vma(current)) {
+
+		/*
+		 * User mapped kernel pages or huge pages:
+		 * make these pages present to populate the ptes, but
+		 * fall thru' to reset VM_LOCKED--no need to unlock, and
+		 * return nr_pages so these don't get counted against task's
+		 * locked limit.  huge pages are already counted against
+		 * locked vm limit.
+		 */
+		make_pages_present(start, end);
+		goto no_mlock;
+	}
 
+	if (vma->vm_flags & VM_NONLINEAR)
+		/*
+		 * try_to_munmap() doesn't treat VM_NONLINEAR. let's make
+		 * consist.
+		 */
+		make_pages_present(start, end);
+	else
 		__mlock_vma_pages_range(vma, start, end);
 
-		/* Hide errors from mmap() and other callers */
-		return 0;
-	}
+	/* Hide errors from mmap() and other callers */
+	return 0;
 
-	/*
-	 * User mapped kernel pages or huge pages:
-	 * make these pages present to populate the ptes, but
-	 * fall thru' to reset VM_LOCKED--no need to unlock, and
-	 * return nr_pages so these don't get counted against task's
-	 * locked limit.  huge pages are already counted against
-	 * locked vm limit.
-	 */
-	make_pages_present(start, end);
 
 no_mlock:
 	vma->vm_flags &= ~VM_LOCKED;	/* and don't come back! */
-- 
1.6.2.5



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