s3: smbd: Change aio_pending_size static variable to a new "aio max threads" smb.conf parameter.

Removes accessor functions as now this parameter is set
under user control in smb.conf. Default is 100.

Note that this doesn't limit the number of outstanding
aio requests, it just causes them to go onto the
pthreadpool queue.

Now we need to prioritize pthreadpool pipe replies
ahead of incoming SMB2 requests, but that's a patch
for another day.

Based on ideas from Volker.

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Christof Schmitt <cs@samba.org>
Reviewed-by: Michael Adam <obnox@samba.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/docs-xml/smbdotconf/tuning/aiomaxthreads.xml b/docs-xml/smbdotconf/tuning/aiomaxthreads.xml
new file mode 100644
index 00000000000..3afe989f5ce
--- /dev/null
+++ b/docs-xml/smbdotconf/tuning/aiomaxthreads.xml
@@ -0,0 +1,19 @@
+<samba:parameter name="aio max threads"
+                 type="integer"
+                 context="G"
+                 xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
+<description>
+  <para>
+    The integer parameter specifies the maximum number of
+    threads each smbd process will create when doing parallel asynchronous IO
+    calls. If the number of outstanding calls is greater than this
+    number the requests will not be refused but go onto a queue
+    and will be scheduled in turn as outstanding requests complete.
+  </para>
+
+  <related>aio read size</related>
+  <related>aio write size</related>
+</description>
+
+<value type="default">100</value>
+</samba:parameter>