nodeinfo: Use a bitmap to keep track of node CPUs

Keep track of what CPUs belong to the current node while walking
through the sysfs node entry, so we don't need to do it a second
time immediately afterwards.

This also allows us to loop through all CPUs that are part of a
node in guaranteed ascending order, which is something that is
required for some upcoming changes.

src/nodeinfo.c

@@ -411,8 +411,10 @@ virNodeParseNode(const char *sysfs_prefix,
     struct dirent *cpudirent = NULL;
     virBitmapPtr present_cpumap = NULL;
     virBitmapPtr online_cpus_map = NULL;
+    virBitmapPtr node_cpus_map = NULL;
     virBitmapPtr sockets_map = NULL;
     virBitmapPtr *cores_maps = NULL;
+    int npresent_cpus;
     int sock_max = 0;
     int sock;
     int core;
@@ -437,6 +439,12 @@ virNodeParseNode(const char *sysfs_prefix,
     if (!online_cpus_map)
         goto cleanup;
 
+    npresent_cpus = virBitmapSize(present_cpumap);
+
+    /* Keep track of the CPUs that belong to the current node */
+    if (!(node_cpus_map = virBitmapNew(npresent_cpus)))
+        goto cleanup;
+
     /* enumerate sockets in the node */
     if (!(sockets_map = virBitmapNew(ID_MAX + 1)))
         goto cleanup;
@@ -448,6 +456,10 @@ virNodeParseNode(const char *sysfs_prefix,
         if (!virBitmapIsBitSet(present_cpumap, cpu))
             continue;
 
+        /* Mark this CPU as part of the current node */
+        if (virBitmapSetBit(node_cpus_map, cpu) < 0)
+            goto cleanup;
+
         if (!virBitmapIsBitSet(online_cpus_map, cpu))
             continue;
 
@@ -481,13 +493,11 @@ virNodeParseNode(const char *sysfs_prefix,
         if (!(cores_maps[i] = virBitmapNew(ID_MAX + 1)))
             goto cleanup;
 
-    /* iterate over all CPU's in the node */
-    rewinddir(cpudir);
-    while ((direrr = virDirRead(cpudir, &cpudirent, node)) > 0) {
-        if (sscanf(cpudirent->d_name, "cpu%u", &cpu) != 1)
-            continue;
+    /* Iterate over all CPUs in the node, in ascending order */
+    for (cpu = 0; cpu < npresent_cpus; cpu++) {
 
-        if (!virBitmapIsBitSet(present_cpumap, cpu))
+        /* Skip CPUs that are not part of the current node */
+        if (!virBitmapIsBitSet(node_cpus_map, cpu))
             continue;
 
         if (!virBitmapIsBitSet(online_cpus_map, cpu)) {
@@ -530,9 +540,6 @@ virNodeParseNode(const char *sysfs_prefix,
             *threads = siblings;
     }
 
-    if (direrr < 0)
-        goto cleanup;
-
     /* finalize the returned data */
     *sockets = virBitmapCountBits(sockets_map);
 
@@ -558,6 +565,7 @@ virNodeParseNode(const char *sysfs_prefix,
             virBitmapFree(cores_maps[i]);
     VIR_FREE(cores_maps);
     virBitmapFree(sockets_map);
+    virBitmapFree(node_cpus_map);
     virBitmapFree(online_cpus_map);
     virBitmapFree(present_cpumap);