mm: enable MADV_FREE for swapless system
Now MADV_FREE pages can be easily reclaimed even for swapless system.
We can safely enable MADV_FREE for all systems.
Link: http://lkml.kernel.org/r/155648585589300bfae1d45078e7aebb3d988b87.1487965799.git.shli@fb.com
Signed-off-by: Shaohua Li <shli@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/madvise.c b/mm/madvise.c
index d3a6712..a09d2d3 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -650,13 +650,7 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
case MADV_WILLNEED:
return madvise_willneed(vma, prev, start, end);
case MADV_FREE:
- /*
- * XXX: In this implementation, MADV_FREE works like
- * MADV_DONTNEED on swapless system or full swap.
- */
- if (get_nr_swap_pages() > 0)
- return madvise_free(vma, prev, start, end);
- /* passthrough */
+ return madvise_free(vma, prev, start, end);
case MADV_DONTNEED:
return madvise_dontneed(vma, prev, start, end);
default: