[PATCH 2/2] posix_fadvise.2: Document the behaviour of partial page discard requests

[Mel Gorman <mgorman@suse.de>]

It is not obvious from the interface that partial page discard requests
are ignored. It should be spelled out.

Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 man2/posix_fadvise.2 | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/man2/posix_fadvise.2 b/man2/posix_fadvise.2
index 25d0c50..07313a9 100644
--- a/man2/posix_fadvise.2
+++ b/man2/posix_fadvise.2
@@ -144,6 +144,11 @@ A program may periodically request the kernel to free cached data
 that has already been used, so that more useful cached pages are not
 discarded instead.
 
+Requests to discard partial pages are ignored. It is preferable to preserve
+needed data than discard unneeded data. If the application requires that
+data be considered for discarding then \fIoffset\fP and \fIlen\fP must be
+page-aligned.
+
 Pages that have not yet been written out will be unaffected, so if the
 application wishes to guarantee that pages will be released, it should
 call