[PATCH 2/2] virnuma: Use numa_nodes_ptr when checking available NUMA nodes

Michal Privoznik mprivozn at redhat.com
Fri Sep 11 11:45:12 UTC 2020

In v6.7.0-rc1~86 I've tried to fix a problem where we were not
detecting NUMA nodes properly because we misused behaviour of a
libnuma API and as it turned out the behaviour was correct for
hosts with 64 CPUs in one NUMA node. So I changed the code to use
nodemask_isset(&numa_all_nodes, ..) instead and it fixed the
problem on such hosts. However, what I did not realize is that
numa_all_nodes does not reflect all NUMA nodes visible to
userspace, it contains only those nodes that the process
(libvirtd) an allocate memory from, which can be only a subset of
all NUMA nodes. The bitmask that contains all NUMA nodes visible
to userspace and which one I should have used is: numa_nodes_ptr.
For curious ones:


And as I was fixing virNumaGetNodeCPUs() I came to realize that
we already have a function that wraps the correct bitmask:

Fixes: 24d7d85208f812a45686b32a0561cc9c5c9a49c9
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1876956
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
 src/util/virnuma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/util/virnuma.c b/src/util/virnuma.c
index b8cf8b4510..39f0f30917 100644
--- a/src/util/virnuma.c
+++ b/src/util/virnuma.c
@@ -260,7 +260,7 @@ virNumaGetNodeCPUs(int node,
     *cpus = NULL;
-    if (!nodemask_isset(&numa_all_nodes, node)) {
+    if (!virNumaNodeIsAvailable(node)) {
         VIR_DEBUG("NUMA topology for cell %d is not available, ignoring", node);
         return -2;

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