When hot-adding vcpus qemu needs to allocate some structures in the DMA
zone which may be outside of the numa pinning. Extract the code doing
this in a set of helpers so that it can be reused.
---
src/qemu/qemu_cgroup.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++
src/qemu/qemu_cgroup.h | 11 ++++++
src/qemu/qemu_driver.c | 36 +++-----------------
3 files changed, 105 insertions(+), 32 deletions(-)
diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index 2dca874..e2b5bab 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -1127,3 +1127,93 @@ qemuRemoveCgroup(virDomainObjPtr vm)
return virCgroupRemove(priv->cgroup);
}
+
+
+static void
+qemuCgroupEmulatorAllNodesDataFree(qemuCgroupEmulatorAllNodesDataPtr data)
+{
+ if (!data)
+ return;
+
+ virCgroupFree(&data->emulatorCgroup);
+ VIR_FREE(data->emulatorMemMask);
+ VIR_FREE(data);
+}
+
+
+/**
+ * qemuCgroupEmulatorAllNodesAllow:
+ * @cgroup: domain cgroup pointer
+ * @retData: filled with structure used to roll back the operation
+ *
+ * Allows all NUMA nodes for the qemu emulator thread temporarily. This is
+ * necessary when hotplugging cpus since it requires memory allocated in the
+ * DMA region. Afterwards the operation can be reverted by
+ * qemuCgrouEmulatorAllNodesRestore.
+ *
+ * Returns 0 on success -1 on error
+ */
+int
+qemuCgroupEmulatorAllNodesAllow(virCgroupPtr cgroup,
+ qemuCgroupEmulatorAllNodesDataPtr *retData)
+{
+ qemuCgroupEmulatorAllNodesDataPtr data = NULL;
+ char *all_nodes_str = NULL;
+ virBitmapPtr all_nodes = NULL;
+ int ret = -1;
+
+ if (!virNumaIsAvailable() ||
+ !virCgroupHasController(cgroup, VIR_CGROUP_CONTROLLER_CPUSET))
+ return 0;
+
+ if (!(all_nodes = virNumaGetHostNodeset()))
+ goto cleanup;
+
+ if (!(all_nodes_str = virBitmapFormat(all_nodes)))
+ goto cleanup;
+
+ if (VIR_ALLOC(data) < 0)
+ goto cleanup;
+
+ if (virCgroupNewThread(cgroup, VIR_CGROUP_THREAD_EMULATOR, 0,
+ false, &data->emulatorCgroup) < 0)
+ goto cleanup;
+
+ if (virCgroupGetCpusetMems(data->emulatorCgroup, &data->emulatorMemMask) < 0 ||
+ virCgroupSetCpusetMems(data->emulatorCgroup, all_nodes_str) < 0)
+ goto cleanup;
+
+ VIR_STEAL_PTR(*retData, data);
+ ret = 0;
+
+ cleanup:
+ VIR_FREE(all_nodes_str);
+ virBitmapFree(all_nodes);
+ qemuCgroupEmulatorAllNodesDataFree(data);
+
+ return ret;
+}
+
+
+/**
+ * qemuCgrouEmulatorAllNodesRestore:
+ * @data: data structure created by qemuCgroupEmulatorAllNodesAllow
+ *
+ * Rolls back the setting done by qemuCgroupEmulatorAllNodesAllow and frees the
+ * associated data.
+ */
+void
+qemuCgrouEmulatorAllNodesRestore(qemuCgroupEmulatorAllNodesDataPtr data)
+{
+ virErrorPtr err;
+
+ if (!data)
+ return;
+
+ err = virSaveLastError();
+ virCgroupSetCpusetMems(data->emulatorCgroup, data->emulatorMemMask);
+ virSetError(err);
+ virFreeError(err);
+
+ qemuCgroupEmulatorAllNodesDataFree(data);
+}
diff --git a/src/qemu/qemu_cgroup.h b/src/qemu/qemu_cgroup.h
index dc340a1..e6ebae0 100644
--- a/src/qemu/qemu_cgroup.h
+++ b/src/qemu/qemu_cgroup.h
@@ -57,4 +57,15 @@ int qemuSetupCgroupCpusetCpus(virCgroupPtr cgroup, virBitmapPtr cpumask);
int qemuSetupGlobalCpuCgroup(virDomainObjPtr vm);
int qemuRemoveCgroup(virDomainObjPtr vm);
+typedef struct _qemuCgroupEmulatorAllNodesData qemuCgroupEmulatorAllNodesData;
+typedef qemuCgroupEmulatorAllNodesData *qemuCgroupEmulatorAllNodesDataPtr;
+struct _qemuCgroupEmulatorAllNodesData {
+ virCgroupPtr emulatorCgroup;
+ char *emulatorMemMask;
+};
+
+int qemuCgroupEmulatorAllNodesAllow(virCgroupPtr cgroup,
+ qemuCgroupEmulatorAllNodesDataPtr *data);
+void qemuCgrouEmulatorAllNodesRestore(qemuCgroupEmulatorAllNodesDataPtr data);
+
#endif /* __QEMU_CGROUP_H__ */
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 807e06d..07d33d3 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -4853,11 +4853,7 @@ qemuDomainSetVcpusLive(virQEMUDriverPtr driver,
unsigned int nvcpus)
{
qemuDomainObjPrivatePtr priv = vm->privateData;
- virCgroupPtr cgroup_temp = NULL;
- char *mem_mask = NULL;
- char *all_nodes_str = NULL;
- virBitmapPtr all_nodes = NULL;
- virErrorPtr err = NULL;
+ qemuCgroupEmulatorAllNodesDataPtr emulatorCgroup = NULL;
virBitmapPtr vcpumap = NULL;
ssize_t nextvcpu = -1;
int rc = 0;
@@ -4866,22 +4862,8 @@ qemuDomainSetVcpusLive(virQEMUDriverPtr driver,
if (!(vcpumap = qemuDomainSelectHotplugVcpuEntities(vm->def, nvcpus)))
goto cleanup;
- if (virNumaIsAvailable() &&
- virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPUSET)) {
- if (virCgroupNewThread(priv->cgroup, VIR_CGROUP_THREAD_EMULATOR, 0,
- false, &cgroup_temp) < 0)
- goto cleanup;
-
- if (!(all_nodes = virNumaGetHostNodeset()))
- goto cleanup;
-
- if (!(all_nodes_str = virBitmapFormat(all_nodes)))
- goto cleanup;
-
- if (virCgroupGetCpusetMems(cgroup_temp, &mem_mask) < 0 ||
- virCgroupSetCpusetMems(cgroup_temp, all_nodes_str) < 0)
- goto cleanup;
- }
+ if (qemuCgroupEmulatorAllNodesAllow(priv->cgroup, &emulatorCgroup) < 0)
+ goto cleanup;
if (nvcpus > virDomainDefGetVcpus(vm->def)) {
while ((nextvcpu = virBitmapNextSetBit(vcpumap, nextvcpu)) != -1) {
@@ -4909,17 +4891,7 @@ qemuDomainSetVcpusLive(virQEMUDriverPtr driver,
ret = 0;
cleanup:
- if (mem_mask) {
- err = virSaveLastError();
- virCgroupSetCpusetMems(cgroup_temp, mem_mask);
- virSetError(err);
- virFreeError(err);
- VIR_FREE(mem_mask);
- }
-
- VIR_FREE(all_nodes_str);
- virBitmapFree(all_nodes);
- virCgroupFree(&cgroup_temp);
+ qemuCgrouEmulatorAllNodesRestore(emulatorCgroup);
virBitmapFree(vcpumap);
return ret;
--
2.10.0
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