From 31ddc55d25a277951f8dc9108925155380a610ad Mon Sep 17 00:00:00 2001
From: David Rientjes <rientjes@google.com>
Date: Thu, 2 Apr 2015 15:21:50 -0700
Subject: [PATCH] madvise.2: Specify MADV_REMOVE returns EINVAL for hugetlbfs

madvise(2) actually returns with error EINVAL for MADV_REMOVE
when used for hugetlb VMAs, not EOPNOTSUPP, and this has been
the case since MADV_REMOVE was introduced in commit f6b3ec238d12
("madvise(MADV_REMOVE): remove pages from tmpfs shm backing
store").

Specify the exact behavior.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man2/madvise.2 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/man2/madvise.2 b/man2/madvise.2
index a3d93bbc3..00db39d89 100644
--- a/man2/madvise.2
+++ b/man2/madvise.2
@@ -184,7 +184,9 @@ any filesystem which supports the
 .BR FALLOC_FL_PUNCH_HOLE
 mode also supports
 .BR MADV_REMOVE .
-Other filesystems fail with the error
+Hugetlbfs will fail with the error
+.BR EINVAL
+and other filesystems fail with the error
 .BR EOPNOTSUPP .
 .TP
 .BR MADV_DONTFORK " (since Linux 2.6.16)"