[libvirt] [PATCH 4/4] qemu: Fix qemuProcessInitCpuAffinity()
Commit f136b83139c6 made some changes in the way we set CPU
affinity for QEMU processes, and while doing so unfortunately
also introduced a logic bug in that it tried to use a NUMA node
map where a CPU map was expected.
Because of that, guests using <numatune> would suddenly fail to
start:
# virsh start guest
error: Failed to start domain guest
error: cannot set CPU affinity on process 40055: Invalid argument
This was particularly easy to trigger on POWER 8 machines,
where secondary threads always show up as offline in the host:
having
<numatune>
<memory mode='strict' placement='static' nodeset='1'/>
</numatune>
in the guest configuration, for example, would result in libvirt
trying to set the process affinity so that it would prefer
running on CPU 1, but since that's a secondary thread and thus
shows up as offline, the operation would fail, and so would
starting the guest.
Use the newly introduced virNumaNodesetToCPUset() to convert
the NUMA node map to a CPU map, which in the example above would
be 8-15 with CPU 8 showing up as online in the guest.
https://bugzilla.redhat.com/show_bug.cgi?id=1703661
Signed-off-by: Andrea Bolognani <abologna(a)redhat.com>
---
src/qemu/qemu_process.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index fa5909e9be..295ad2e1ff 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2489,11 +2489,16 @@ qemuProcessInitCpuAffinity(virDomainObjPtr vm)
if (virDomainNumaGetNodeCount(vm->def->numa) <= 1 &&
virDomainNumatuneGetMode(vm->def->numa, -1, &mem_mode) == 0 &&
mem_mode == VIR_DOMAIN_NUMATUNE_MEM_STRICT) {
+ virBitmapPtr nodeset = NULL;
+
if (virDomainNumatuneMaybeGetNodeset(vm->def->numa,
priv->autoNodeset,
- &cpumapToSet,
+ &nodeset,
-1) < 0)
goto cleanup;
+
+ if (virNumaNodesetToCPUset(nodeset, &cpumapToSet) < 0)
+ goto cleanup;
} else if (vm->def->cputune.emulatorpin) {
cpumapToSet = vm->def->cputune.emulatorpin;
} else {
--
2.21.0