From 0e264e7ac2b311aa9b42b183660a07b7e4e36b11 Mon Sep 17 00:00:00 2001
From: Jim Gauld <james.gauld@windriver.com>
Date: Fri, 9 Jun 2017 14:58:23 -0400
Subject: [PATCH 1/1] CGTS-7164: Add resource options cpu-mask to affine drbd
 kernel threads

This adds "options { cpu-mask <cpumask>; }" section to DRBD resource
configuration if 'cpumask' hexstring is defined. This governs kernel
threads: drbd_w_<x>, drbd_r_<x>, drbd_a_<x>.

Related notes:
- if cpumask is not specified, the kernel threads drbd_w_<x>, drbd_r_<x>,
  drbd_a_<x>, and drbd_as_<x> are affined to individual cores, each <x>
  on a different core.

- the remainder of the kernel threads are governed by kernel boot
  argument kthread_cpus=<cpulist>.  i.e., drbd-reissue, drbd<x>_submit,
  jbd2/drbd<x>-8, drbd_as_<x>.

- the drbd_a_<x> and drbd_as_<x> show up when DRBD is duplex.

- the drbd_a_<x> threads have SCHED_RR scheduling policy.
---
 manifests/resource.pp    | 3 +++
 templates/header.res.erb | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/manifests/resource.pp b/manifests/resource.pp
index d19ad8b..17e6142 100644
--- a/manifests/resource.pp
+++ b/manifests/resource.pp
@@ -26,6 +26,8 @@
 #  [link_speed] replication link network speed mbps
 #  [num_parallel] number of parallel drbd filesystems to sync
 #  [rtt_ms] round-trip-time milliseconds (i.e., ping between replication nodes)
+#  [cpumask] cpu-affinity-mask for DRBD kernel threads (hexidecimal notation).
+#    0 means spread over all CPUs of the machine.
 define drbd::resource (
   $host1          = undef,
   $host2          = undef,
@@ -48,6 +50,7 @@ define drbd::resource (
   $num_parallel   = false,
   $rtt_ms         = false,
   $resync_after   = undef,
+  $cpumask        = false,
   $net_parameters = false,
   $manage         = true,
   $ha_primary     = false,
diff --git a/templates/header.res.erb b/templates/header.res.erb
index be53761..df52544 100644
--- a/templates/header.res.erb
+++ b/templates/header.res.erb
@@ -29,6 +29,12 @@ resource <%= @name %> {
 <% end -%>
   }
 
+<% if @cpumask -%>
+  options {
+    cpu-mask <%= @cpumask %>;
+  }
+<% end -%>
+
   net {
     after-sb-0pri discard-zero-changes;
     after-sb-1pri discard-secondary;
-- 
1.8.3.1