lkml.org 
[lkml]   [2015]   [Jul]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch] mmap.2: document the munmap exception for underlying page size
munmap(2) will fail with an errno of EINVAL for hugetlb memory if the 
length is not a multiple of the underlying page size.

Documentation/vm/hugetlbpage.txt was updated to specify this behavior
since Linux 4.1 in commit 80d6b94bd69a ("mm, doc: cleanup and clarify
munmap behavior for hugetlb memory").

Signed-off-by: David Rientjes <rientjes@google.com>
---
man2/mmap.2 | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/man2/mmap.2 b/man2/mmap.2
--- a/man2/mmap.2
+++ b/man2/mmap.2
@@ -383,6 +383,10 @@ All pages containing a part
of the indicated range are unmapped, and subsequent references
to these pages will generate
.BR SIGSEGV .
+An exception is when the underlying memory is not of the native page
+size, such as hugetlb page sizes, whereas
+.I length
+must be a multiple of the underlying page size.
It is not an error if the
indicated range does not contain any mapped pages.
.SS Timestamps changes for file-backed mappings

\
 
 \ /
  Last update: 2015-07-22 03:01    [W:0.411 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site