numa: Rename virNumaGetHostNodeset and make it return only nodes with memory

Name it virNumaGetHostMemoryNodeset and return only NUMA nodes which
have memory installed. This is necessary as the kernel is not very happy
to set the memory cgroup setting for nodes which do not have any memory.

This would break vcpu hotplug with following message on such
configruation:

  Invalid value '0,8' for 'cpuset.mems': Invalid argument

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1375268

src/libvirt_private.syms

@@ -2059,7 +2059,7 @@ virNodeSuspendGetTargetMask;
 # util/virnuma.h
 virNumaGetAutoPlacementAdvice;
 virNumaGetDistances;
-virNumaGetHostNodeset;
+virNumaGetHostMemoryNodeset;
 virNumaGetMaxNode;
 virNumaGetNodeMemory;
 virNumaGetPageInfo;

src/qemu/qemu_cgroup.c

@@ -860,7 +860,7 @@ qemuRestoreCgroupState(virDomainObjPtr vm)
     virBitmapPtr all_nodes;
     virCgroupPtr cgroup_temp = NULL;
 
-    if (!(all_nodes = virNumaGetHostNodeset()))
+    if (!(all_nodes = virNumaGetHostMemoryNodeset()))
         goto error;
 
     if (!(mem_mask = virBitmapFormat(all_nodes)))
@@ -1166,7 +1166,7 @@ qemuCgroupEmulatorAllNodesAllow(virCgroupPtr cgroup,
         !virCgroupHasController(cgroup, VIR_CGROUP_CONTROLLER_CPUSET))
         return 0;
 
-    if (!(all_nodes = virNumaGetHostNodeset()))
+    if (!(all_nodes = virNumaGetHostMemoryNodeset()))
         goto cleanup;
 
     if (!(all_nodes_str = virBitmapFormat(all_nodes)))

src/util/virnuma.c

@@ -987,10 +987,17 @@ virNumaNodesetIsAvailable(virBitmapPtr nodeset)
     return true;
 }
 
+
+/**
+ * virNumaGetHostMemoryNodeset:
+ *
+ * Returns a bitmap of guest numa node ids that contain memory.
+ */
 virBitmapPtr
-virNumaGetHostNodeset(void)
+virNumaGetHostMemoryNodeset(void)
 {
     int maxnode = virNumaGetMaxNode();
+    unsigned long long nodesize;
     size_t i = 0;
     virBitmapPtr nodeset = NULL;
 
@@ -1004,7 +1011,9 @@ virNumaGetHostNodeset(void)
         if (!virNumaNodeIsAvailable(i))
             continue;
 
-        ignore_value(virBitmapSetBit(nodeset, i));
+        /* if we can't detect NUMA node size assume that it's present */
+        if (virNumaGetNodeMemory(i, &nodesize, NULL) < 0 || nodesize > 0)
+            ignore_value(virBitmapSetBit(nodeset, i));
     }
 
     return nodeset;

src/util/virnuma.h

@@ -33,7 +33,7 @@ char *virNumaGetAutoPlacementAdvice(unsigned short vcups,
 int virNumaSetupMemoryPolicy(virDomainNumatuneMemMode mode,
                              virBitmapPtr nodeset);
 
-virBitmapPtr virNumaGetHostNodeset(void);
+virBitmapPtr virNumaGetHostMemoryNodeset(void);
 bool virNumaNodesetIsAvailable(virBitmapPtr nodeset);
 bool virNumaIsAvailable(void);
 int virNumaGetMaxNode(void);