ovs-ctl: Allow to set oom-score for ovs daemons.

Allow to set oom-score with --oom-score argument.
This argument can be set in ovs config file.
In rhel can set OPTIONS in /etc/sysconfig/openvswitch.
In debian can set OVS_CTL_OPTS in /etc/default/openvswitch-switch.

Acked-by: Eli Britstein <elibr@nvidia.com>
Acked-by: Simon Horman <horms@ovn.org>
Signed-off-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>

Documentation/ref/ovs-ctl.8.rst

@@ -194,6 +194,11 @@ The following options are less important:
     place, because, perhaps, OVSDB manager is running on the same host
     as OVS and share similar attack vectors.
 
+* ``--oom-score=<score>``
+
+  Sets the Linux Out-Of-Memory (OOM) killer score for the OVS daemon
+  after it's been started.
+
 * ``--ovsdb-server-priority=<niceness>`` or
   ``--ovs-vswitchd-priority=<niceness>``
 

NEWS

@@ -2,6 +2,9 @@ Post-v3.5.0
 --------------------
    - DPDK:
      * New debug appctl command 'dpdk/get-memzone-stats'.
+   - ovs-ctl:
+     * Added a new option, --oom-score=<score>, to set the daemons' Linux
+       Out-Of-Memory (OOM) killer score.
 
 
 v3.5.0 - xx xxx xxxx

utilities/ovs-ctl.in

@@ -356,6 +356,7 @@ set_defaults () {
     OVS_MONITOR_IPSEC_OPTIONS=
     OVSDB_SERVER_UMASK=
     OVS_VSWITCHD_UMASK=
+    OOM_SCORE=
 
     DB_FILE=$dbdir/conf.db
     DB_SOCK=$rundir/db.sock
@@ -448,6 +449,7 @@ Less important options for "start", "restart" and "force-reload-kmod":
   --no-full-hostname             set short hostname instead of full hostname
   --no-record-hostname           do not attempt to determine/record system
                                  hostname as part of start command
+  --oom-score=SCORE              Set oom-score after starting ovs daemon.
 
 Debugging options for "start", "restart" and "force-reload-kmod":
   --ovsdb-server-wrapper=WRAPPER

utilities/ovs-lib.in

@@ -236,6 +236,10 @@ start_daemon () {
         umask "$previuos_umask_value"
     fi
 
+    if test X"$OOM_SCORE" != X; then
+        echo "$OOM_SCORE" > /proc/`cat $rundir/$daemon.pid`/oom_score_adj 2>/dev/null
+    fi
+
     if test X"$strace" != X; then
         # Strace doesn't have the -D option so we attach after the fact.
         setsid $strace -o "$logdir/$daemon.strace.log" \