freeing them.
page_evictable() also checks for mlocked pages by testing an additional page
-flag, PG_mlocked (as wrapped by PageMlocked()). If the page is NOT mlocked,
-and a non-NULL VMA is supplied, page_evictable() will check whether the VMA is
-VM_LOCKED via is_mlocked_vma(). is_mlocked_vma() will SetPageMlocked() and
-update the appropriate statistics if the vma is VM_LOCKED. This method allows
-efficient "culling" of pages in the fault path that are being faulted in to
-VM_LOCKED VMAs.
+flag, PG_mlocked (as wrapped by PageMlocked()), which is set when a page is
+faulted into a VM_LOCKED vma, or found in a vma being VM_LOCKED.
VMSCAN'S HANDLING OF UNEVICTABLE PAGES
-------------------------------
shrink_active_list() culls any obviously unevictable pages - i.e.
-!page_evictable(page, NULL) - diverting these to the unevictable list.
+!page_evictable(page) - diverting these to the unevictable list.
However, shrink_active_list() only sees unevictable pages that made it onto the
active/inactive lru lists. Note that these pages do not have PageUnevictable
set - otherwise they would be on the unevictable list and shrink_active_list