[libvirt] [PATCHv4 02/18] util: Introduce resctrl monitor for CMT

[Wang Huaqiang]

Cache Monitoring Technology (aka CMT) provides the capability
to report cache utilization information of system task.

This patch introduces the concept of resctrl monitor through
data structure virResctrlMonitor.

Signed-off-by: Wang Huaqiang <huaqiang.wang at intel.com>
---
 src/libvirt_private.syms |  1 +
 src/util/virresctrl.c    | 56 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/util/virresctrl.h    |  7 ++++++
 3 files changed, 64 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 9236391..754578f 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2677,6 +2677,7 @@ virResctrlInfoGetCache;
 virResctrlInfoGetMonitorPrefix;
 virResctrlInfoMonFree;
 virResctrlInfoNew;
+virResctrlMonitorNew;
 
 
 # util/virrotatingfile.h
diff --git a/src/util/virresctrl.c b/src/util/virresctrl.c
index 74d9b6b..bd36406 100644
--- a/src/util/virresctrl.c
+++ b/src/util/virresctrl.c
@@ -105,6 +105,7 @@ typedef virResctrlAllocMemBW *virResctrlAllocMemBWPtr;
 /* Class definitions and initializations */
 static virClassPtr virResctrlInfoClass;
 static virClassPtr virResctrlAllocClass;
+static virClassPtr virResctrlMonitorClass;
 
 
 /* virResctrlInfo */
@@ -319,6 +320,35 @@ struct _virResctrlAlloc {
     char *path;
 };
 
+/* virResctrlMonitor */
+
+/*
+ * virResctrlMonitor is the data structure for resctrl monitor. Resctrl
+ * monitor represents a resctrl monitoring group, which can be used to
+ * monitor the resource utilization information for either cache or
+ * memory bandwidth.
+ *
+ * From hardware perspective, cache monitoring technology (CMT), memory
+ * bandwidth technology (MBM), as well as the CAT and MBA, are all orthogonal
+ * features. The monitor will be created under the scope of default allocation
+ * if no CAT or MBA supported in the system.
+ */
+struct _virResctrlMonitor {
+    virObject parent;
+
+    /* In resctrl, each monitor is associated with one specific allocation,
+     * either the allocation under /sys/fs/resctrl or the default allocation.
+     * If this pointer is NULL, then the monitor will be associated with
+     * default allocation, otherwise, this pointer points to the allocation
+     * this monitor associated with. */
+    virResctrlAllocPtr alloc;
+    /* The monitor identifier */
+    char *id;
+    /* libvirt-generated path in /sys/fs/resctrl for this particular
+     * monitor */
+    char *path;
+};
+
 
 static void
 virResctrlAllocDispose(void *obj)
@@ -368,6 +398,17 @@ virResctrlAllocDispose(void *obj)
 }
 
 
+static void
+virResctrlMonitorDispose(void *obj)
+{
+    virResctrlMonitorPtr monitor = obj;
+
+    virObjectUnref(monitor->alloc);
+    VIR_FREE(monitor->id);
+    VIR_FREE(monitor->path);
+}
+
+
 /* Global initialization for classes */
 static int
 virResctrlOnceInit(void)
@@ -378,6 +419,9 @@ virResctrlOnceInit(void)
     if (!VIR_CLASS_NEW(virResctrlAlloc, virClassForObject()))
         return -1;
 
+    if (!VIR_CLASS_NEW(virResctrlMonitor, virClassForObject()))
+        return -1;
+
     return 0;
 }
 
@@ -2374,3 +2418,15 @@ virResctrlAllocRemove(virResctrlAllocPtr alloc)
 
     return ret;
 }
+
+
+/* virResctrlMonitor-related definitions */
+
+virResctrlMonitorPtr
+virResctrlMonitorNew(void)
+{
+    if (virResctrlInitialize() < 0)
+        return NULL;
+
+    return virObjectNew(virResctrlMonitorClass);
+}
diff --git a/src/util/virresctrl.h b/src/util/virresctrl.h
index 10505e9..f59a9aa 100644
--- a/src/util/virresctrl.h
+++ b/src/util/virresctrl.h
@@ -185,4 +185,11 @@ int
 virResctrlInfoGetMonitorPrefix(virResctrlInfoPtr resctrl,
                                const char *prefix,
                                virResctrlInfoMonPtr *monitor);
+
+/* Monitor-related things */
+typedef struct _virResctrlMonitor virResctrlMonitor;
+typedef virResctrlMonitor *virResctrlMonitorPtr;
+
+virResctrlMonitorPtr
+virResctrlMonitorNew(void);
 #endif /*  __VIR_RESCTRL_H__ */
-- 
2.7.4