util: Add more interfaces for resctrl monitor

Add interfaces monitor group to support operations such
as GetID, SetID, Remove, SetAlloc, etc.

Implement the internal virResctrlMonitorGetStats to fetch all
the statistical data and the virResctrlMonitorGetCacheOccupancy
in order to fetch the cache specific "llc_occupancy" value.
Signed-off-by: NWang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

src/libvirt_private.syms

@@ -2684,7 +2684,12 @@ virResctrlInfoNew;
 virResctrlMonitorAddPID;
 virResctrlMonitorCreate;
 virResctrlMonitorDeterminePath;
+virResctrlMonitorGetCacheOccupancy;
+virResctrlMonitorGetID;
 virResctrlMonitorNew;
+virResctrlMonitorRemove;
+virResctrlMonitorSetAlloc;
+virResctrlMonitorSetID;
 
 
 # util/virrotatingfile.h

src/util/virresctrl.c

@@ -2585,3 +2585,179 @@ virResctrlMonitorCreate(virResctrlMonitorPtr monitor,
     virResctrlUnlock(lockfd);
     return ret;
 }
+
+
+int
+virResctrlMonitorSetID(virResctrlMonitorPtr monitor,
+                       const char *id)
+
+{
+    return virResctrlSetID(&monitor->id, id);
+}
+
+
+const char *
+virResctrlMonitorGetID(virResctrlMonitorPtr monitor)
+{
+    return monitor->id;
+}
+
+
+void
+virResctrlMonitorSetAlloc(virResctrlMonitorPtr monitor,
+                          virResctrlAllocPtr alloc)
+{
+    monitor->alloc = virObjectRef(alloc);
+}
+
+
+int
+virResctrlMonitorRemove(virResctrlMonitorPtr monitor)
+{
+    int ret = 0;
+
+    if (!monitor->path)
+        return 0;
+
+    if (STREQ(monitor->path, monitor->alloc->path))
+        return 0;
+
+    VIR_DEBUG("Removing resctrl monitor path=%s", monitor->path);
+    if (rmdir(monitor->path) != 0 && errno != ENOENT) {
+        ret = -errno;
+        VIR_ERROR(_("Unable to remove %s (%d)"), monitor->path, errno);
+    }
+
+    return ret;
+}
+
+
+static int
+virResctrlMonitorStatsSorter(const void *a,
+                             const void *b)
+{
+    return ((virResctrlMonitorStatsPtr)a)->id
+        - ((virResctrlMonitorStatsPtr)b)->id;
+}
+
+
+/*
+ * virResctrlMonitorGetStats
+ *
+ * @monitor: The monitor that the statistic data will be retrieved from.
+ * @resource: The name for resource name. 'llc_occupancy' for cache resource.
+ * "mbm_total_bytes" and "mbm_local_bytes" for memory bandwidth resource.
+ * @stats: Array of virResctrlMonitorStatsPtr for holding cache or memory
+ * bandwidth usage data.
+ * @nstats: A size_t pointer to hold the returned array length of @stats
+ *
+ * Get cache or memory bandwidth utilization information.
+ *
+ * Returns 0 on success, -1 on error.
+ */
+static int
+virResctrlMonitorGetStats(virResctrlMonitorPtr monitor,
+                          const char *resource,
+                          virResctrlMonitorStatsPtr *stats,
+                          size_t *nstats)
+{
+    int rv = -1;
+    int ret = -1;
+    DIR *dirp = NULL;
+    char *datapath = NULL;
+    struct dirent *ent = NULL;
+    virResctrlMonitorStatsPtr stat = NULL;
+
+    if (!monitor) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Invalid resctrl monitor"));
+        return -1;
+    }
+
+    if (virAsprintf(&datapath, "%s/mon_data", monitor->path) < 0)
+        return -1;
+
+    if (virDirOpen(&dirp, datapath) < 0)
+        goto cleanup;
+
+    *nstats = 0;
+    while (virDirRead(dirp, &ent, datapath) > 0) {
+        char *node_id = NULL;
+
+        if (VIR_ALLOC(stat) < 0)
+            goto cleanup;
+
+        /* Looking for directory that contains resource utilization
+         * information file. The directory name is arranged in format
+         * "mon_<node_name>_<node_id>". For example, "mon_L3_00" and
+         * "mon_L3_01" are two target directories for a two nodes system
+         * with resource utilization data file for each node respectively.
+         */
+        if (ent->d_type != DT_DIR)
+            continue;
+
+        /* Looking for directory has a prefix 'mon_L' */
+        if (!(node_id = STRSKIP(ent->d_name, "mon_L")))
+            continue;
+
+        /* Looking for directory has another '_' */
+        node_id = strchr(node_id, '_');
+        if (!node_id)
+            continue;
+
+        /* Skip the character '_' */
+        if (!(node_id = STRSKIP(node_id, "_")))
+            continue;
+
+        /* The node ID number should be here, parsing it. */
+        if (virStrToLong_uip(node_id, NULL, 0, &stat->id) < 0)
+            goto cleanup;
+
+        rv = virFileReadValueUint(&stat->val, "%s/%s/%s", datapath,
+                                  ent->d_name, resource);
+        if (rv == -2) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("File '%s/%s/%s' does not exist."),
+                           datapath, ent->d_name, resource);
+        }
+        if (rv < 0)
+            goto cleanup;
+
+        if (VIR_APPEND_ELEMENT(*stats, *nstats, *stat) < 0)
+            goto cleanup;
+    }
+
+    /* Sort in id's ascending order */
+    if (*nstats)
+        qsort(*stats, *nstats, sizeof(*stat), virResctrlMonitorStatsSorter);
+
+    ret = 0;
+ cleanup:
+    VIR_FREE(datapath);
+    VIR_FREE(stat);
+    VIR_DIR_CLOSE(dirp);
+    return ret;
+}
+
+
+/*
+ * virResctrlMonitorGetCacheOccupancy
+ *
+ * @monitor: The monitor that the statistic data will be retrieved from.
+ * @stats: Array of virResctrlMonitorStatsPtr for receiving cache occupancy
+ * data. Caller is responsible to free this array.
+ * @nstats: A size_t pointer to hold the returned array length of @caches
+ *
+ * Get cache or memory bandwidth utilization information.
+ *
+ * Returns 0 on success, -1 on error.
+ */
+
+int
+virResctrlMonitorGetCacheOccupancy(virResctrlMonitorPtr monitor,
+                                   virResctrlMonitorStatsPtr *stats,
+                                   size_t *nstats)
+{
+    return virResctrlMonitorGetStats(monitor, "llc_occupancy",
+                                     stats, nstats);
+}

src/util/virresctrl.h

@@ -191,6 +191,13 @@ virResctrlInfoGetMonitorPrefix(virResctrlInfoPtr resctrl,
 typedef struct _virResctrlMonitor virResctrlMonitor;
 typedef virResctrlMonitor *virResctrlMonitorPtr;
 
+typedef struct _virResctrlMonitorStats virResctrlMonitorStats;
+typedef virResctrlMonitorStats *virResctrlMonitorStatsPtr;
+struct _virResctrlMonitorStats {
+    unsigned int id;
+    unsigned int val;
+};
+
 virResctrlMonitorPtr
 virResctrlMonitorNew(void);
 
@@ -205,4 +212,23 @@ virResctrlMonitorAddPID(virResctrlMonitorPtr monitor,
 int
 virResctrlMonitorCreate(virResctrlMonitorPtr monitor,
                         const char *machinename);
+
+int
+virResctrlMonitorSetID(virResctrlMonitorPtr monitor,
+                       const char *id);
+
+const char *
+virResctrlMonitorGetID(virResctrlMonitorPtr monitor);
+
+void
+virResctrlMonitorSetAlloc(virResctrlMonitorPtr monitor,
+                          virResctrlAllocPtr alloc);
+
+int
+virResctrlMonitorRemove(virResctrlMonitorPtr monitor);
+
+int
+virResctrlMonitorGetCacheOccupancy(virResctrlMonitorPtr monitor,
+                                   virResctrlMonitorStatsPtr *caches,
+                                   size_t *ncaches);
 #endif /*  __VIR_RESCTRL_H__ */