[PATCH v2 5/5] qemu: Check for thread <=> memory alignment

[Martin Kletzander <mkletzan@xxxxxxxxxx>]

Some settings may be confusing and in case users use numad placement in
combination with static placement we could warn them as it might not be
wanted (but it's not forbidden).

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1254402

Signed-off-by: Martin Kletzander <mkletzan@xxxxxxxxxx>
---
 src/qemu/qemu_process.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 74 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 0aab01fd4d50..c012b6efcab6 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2304,6 +2304,76 @@ qemuProcessSetLinkStates(virQEMUDriverPtr driver,
 }


+static int
+qemuProcessCheckCpusMemsAlignment(virQEMUDriverPtr driver,
+                                  virDomainObjPtr vm,
+                                  virBitmapPtr cpumask,
+                                  const char *mem_mask)
+{
+    int ret = -1;
+    int hostnodes = 0;
+    char *cpumask_str = NULL;
+    char *tmpmask_str = NULL;
+    char *mem_cpus_str = NULL;
+    virCapsPtr caps = NULL;
+    virBitmapPtr tmpmask = NULL;
+    virBitmapPtr mem_cpus = NULL;
+    virBitmapPtr mem_nodes = NULL;
+    virDomainNumatuneMemMode mem_mode;
+
+    if (virDomainNumatuneGetMode(vm->def->numa, -1, &mem_mode) != 0)
+        return 0;
+
+    if (mem_mode != VIR_DOMAIN_NUMATUNE_MEM_STRICT)
+        return 0;
+
+    if (!mem_mask || !cpumask)
+        return 0;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
+    if (!(tmpmask = virBitmapNewCopy(cpumask)))
+        goto cleanup;
+
+    if ((hostnodes = virNumaGetMaxNode()) < 0)
+        goto cleanup;
+
+    if (virBitmapParse(mem_mask, &mem_nodes, hostnodes) < 0)
+        goto cleanup;
+
+    if (!(mem_cpus = virCapabilitiesGetCpusForNodemask(caps, mem_nodes)))
+        goto cleanup;
+
+    virBitmapSubtract(tmpmask, mem_cpus);
+    if (!virBitmapIsAllClear(tmpmask)) {
+        if (!(cpumask_str = virBitmapFormat(cpumask)))
+            goto cleanup;
+
+        if (!(tmpmask_str = virBitmapFormat(tmpmask)))
+            goto cleanup;
+
+        if (!(mem_cpus_str = virBitmapFormat(mem_cpus)))
+            goto cleanup;
+
+        VIR_WARN("CPUs '%s' in cpumask '%s' might not have access to any NUMA "
+                 "node in memory's nodeset '%s' which consists of CPUs: '%s'.",
+                 tmpmask_str, cpumask_str, mem_mask, mem_cpus_str);
+    }
+
+    ret = 0;
+ cleanup:
+    VIR_FREE(mem_cpus_str);
+    VIR_FREE(tmpmask_str);
+    VIR_FREE(cpumask_str);
+    virBitmapFree(mem_nodes);
+    virBitmapFree(mem_cpus);
+    virBitmapFree(tmpmask);
+    virObjectUnref(caps);
+    return ret;
+}
+
+
 /**
  * qemuProcessSetupPid:
  *
@@ -2315,7 +2385,7 @@ qemuProcessSetLinkStates(virQEMUDriverPtr driver,
  * Returns 0 on success, -1 on error.
  */
 static int
-qemuProcessSetupPid(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
+qemuProcessSetupPid(virQEMUDriverPtr driver,
                     virDomainObjPtr vm,
                     pid_t pid,
                     virCgroupThreadName nameval,
@@ -2389,6 +2459,9 @@ qemuProcessSetupPid(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
         if (virCgroupAddTask(cgroup, pid) < 0)
             goto cleanup;

+        if (qemuProcessCheckCpusMemsAlignment(driver, vm,
+                                              use_cpumask, mem_mask) < 0)
+            goto cleanup;
     }

     /* Setup legacy affinity. */
-- 
2.9.0

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