util: Add interface for creating monitor group

Add interface for creating the resource monitoring group according
to '@virResctrlMonitor->path'.
Signed-off-by: NWang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

src/libvirt_private.syms

@@ -2682,6 +2682,7 @@ virResctrlInfoGetMonitorPrefix;
 virResctrlInfoMonFree;
 virResctrlInfoNew;
 virResctrlMonitorAddPID;
+virResctrlMonitorCreate;
 virResctrlMonitorDeterminePath;
 virResctrlMonitorNew;
 

src/util/virresctrl.c

@@ -2546,3 +2546,27 @@ virResctrlMonitorAddPID(virResctrlMonitorPtr monitor,
 {
     return virResctrlAddPID(monitor->path, pid);
 }
+
+
+int
+virResctrlMonitorCreate(virResctrlMonitorPtr monitor,
+                        const char *machinename)
+{
+    int lockfd = -1;
+    int ret = -1;
+
+    if (!monitor)
+        return 0;
+
+    if (virResctrlMonitorDeterminePath(monitor, machinename) < 0)
+        return -1;
+
+    lockfd = virResctrlLockWrite();
+    if (lockfd < 0)
+        return -1;
+
+    ret = virResctrlCreateGroupPath(monitor->path);
+
+    virResctrlUnlock(lockfd);
+    return ret;
+}

src/util/virresctrl.h

@@ -201,4 +201,8 @@ virResctrlMonitorDeterminePath(virResctrlMonitorPtr monitor,
 int
 virResctrlMonitorAddPID(virResctrlMonitorPtr monitor,
                         pid_t pid);
+
+int
+virResctrlMonitorCreate(virResctrlMonitorPtr monitor,
+                        const char *machinename);
 #endif /*  __VIR_RESCTRL_H__ */