[patch -mm] mm, doc: cleanup and clarify munmap behavior for hugetlb memory fix

[David Rientjes <rientjes@google.com>]

Don't only specify munmap(2) behavior with respect the hugetlb memory, all 
other syscalls get naturally aligned to the native page size of the 
processor.  Rather, pick out munmap(2) as a specific example.

Signed-off-by: David Rientjes <rientjes@google.com>
---
 Documentation/vm/hugetlbpage.txt | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Documentation/vm/hugetlbpage.txt b/Documentation/vm/hugetlbpage.txt
index 1270fb1..030977f 100644
--- a/Documentation/vm/hugetlbpage.txt
+++ b/Documentation/vm/hugetlbpage.txt
@@ -313,8 +313,11 @@ into /proc/sys/vm/hugetlb_shm_group.  It is possible for same or different
 applications to use any combination of mmaps and shm* calls, though the mount of
 filesystem will be required for using mmap calls without MAP_HUGETLB.
 
-When using munmap(2) to unmap hugetlb memory, the length specified must be
-hugepage aligned, otherwise it will fail with errno set to EINVAL.
+Syscalls that operate on memory backed by hugetlb pages only have their lengths
+aligned to the native page size of the processor; they will normally fail with
+errno set to EINVAL or exclude hugetlb pages that extend beyond the length if
+not hugepage aligned.  For example, munmap(2) will fail if memory is backed by
+a hugetlb page and the length is smaller than the hugepage size.
 
 
 Examples