Add file:advise/4 - a wrapper to the POSIX syscall posix_fadvise

Useful for informing the Operating System about the access pattern
for a file's data, so that it can adapt the caching strategy to
maximize disk IO performance.

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/kernel/doc/src/file.xml b/lib/kernel/doc/src/file.xml
index c94df62d1f..382262d1ee 100644
--- a/lib/kernel/doc/src/file.xml
+++ b/lib/kernel/doc/src/file.xml
@@ -62,6 +62,25 @@ time() = {{Year, Month, Day}, {Hour, Minute, Second}}
   </section>
   <funcs>
     <func>
+      <name>advise(IoDevice, Offset, Length, Advise) -> ok | {error, Reason}</name>
+      <fsummary>Predeclare an access pattern for file data</fsummary>
+      <type>
+        <v>IoDevice = io_device()</v>
+        <v>Offset = int()</v>
+        <v>Length = int()</v>
+        <v>Advise = posix_file_advise()</v>
+        <v>posix_file_advise() = normal | sequential | random | no_reuse
+          | will_need | dont_need</v>
+        <v>Reason = ext_posix()</v>
+      </type>
+      <desc>
+        <p><c>advise/4</c> can be used to announce an intention to access file
+          data in a specific pattern in the future, thus allowing the
+          operating system to perform appropriate optimizations.</p>
+        <p>On some platforms, this function might have no effect.</p>
+      </desc>
+    </func>
+    <func>
       <name>change_group(Filename, Gid) -> ok | {error, Reason}</name>
       <fsummary>Change group of a file</fsummary>
       <type>