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

From: Mel Gorman
Date: Tue Dec 02 2014 - 19:42:56 EST

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@xxxxxxx>
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
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
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