[libvirt] [PATCH 2/2] numa: Rename virNumaGetHostNodeset and make it return only nodes with memory

[Peter Krempa]

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 |  2 +-
 src/qemu/qemu_cgroup.c   |  4 ++--
 src/util/virnuma.c       | 13 +++++++++++--
 src/util/virnuma.h       |  2 +-
 4 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 2569772..80d5e86 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2059,7 +2059,7 @@ virNodeSuspendGetTargetMask;
 # util/virnuma.h
 virNumaGetAutoPlacementAdvice;
 virNumaGetDistances;
-virNumaGetHostNodeset;
+virNumaGetHostMemoryNodeset;
 virNumaGetMaxNode;
 virNumaGetNodeMemory;
 virNumaGetPageInfo;
diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index fe94613..4bce601 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/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)))
diff --git a/src/util/virnuma.c b/src/util/virnuma.c
index c4d11fa..bebe301 100644
--- a/src/util/virnuma.c
+++ b/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;
diff --git a/src/util/virnuma.h b/src/util/virnuma.h
index 1f3c0ad..f3eef32 100644
--- a/src/util/virnuma.h
+++ b/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);
-- 
2.10.0