Update documentation for write_hint

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 0b80a62368a88efa464704544bd8fb79696e0119..e544634009ef0907dbd2ad0345af45c5326008f9 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1093,11 +1093,29 @@ I/O type
                **random**
                        Advise using **FADV_RANDOM**.
 
-.. option:: fadvise_stream=int
+.. option:: write_hint=str
 
-       Use :manpage:`posix_fadvise(2)` to advise the kernel what stream ID the
-       writes issued belong to. Only supported on Linux. Note, this option may
-       change going forward.
+       Use :manpage:`fcntl(2)` to advise the kernel what life time to expect
+       from a write. Only supported on Linux, as of version 4.13. Accepted
+       values are:
+
+               **none**
+                       No particular life time associated with this file.
+
+               **short**
+                       Data written to this file has a short life time.
+
+               **medium**
+                       Data written to this file has a medium life time.
+
+               **long**
+                       Data written to this file has a long life time.
+
+               **extreme**
+                       Data written to this file has a very long life time.
+
+       The values are all relative to each other, and no absolute meaning
+       should be associated with them.
 
 .. option:: offset=int