[libvirt] [PATCH] Avoid spamming logs with cgroups warnings

[Daniel P. Berrange]

From: "Daniel P. Berrange" <berrange at redhat.com>

The code for putting the emulator threads in a separate cgroup
would spam the logs with warnings

2013-02-27 16:08:26.731+0000: 29624: warning : virCgroupMoveTask:887 : no vm cgroup in controller 3
2013-02-27 16:08:26.731+0000: 29624: warning : virCgroupMoveTask:887 : no vm cgroup in controller 4
2013-02-27 16:08:26.732+0000: 29624: warning : virCgroupMoveTask:887 : no vm cgroup in controller 6

This is because it has only created child cgroups for 3 of the
controllers, but was trying to move the processes from all the
controllers. The fix is to only try to move threads in the
controllers we actually created. Also remove the warning and
make it return a hard error to avoid such lazy callers in the
future.

Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
 src/qemu/qemu_cgroup.c | 5 +++++
 src/util/vircgroup.c   | 3 +--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index e65b486..671d613 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -692,6 +692,11 @@ int qemuSetupCgroupForEmulator(virQEMUDriverPtr driver,
     }
 
     for (i = 0; i < VIR_CGROUP_CONTROLLER_LAST; i++) {
+        if (i != VIR_CGROUP_CONTROLLER_CPU &&
+            i != VIR_CGROUP_CONTROLLER_CPUACCT &&
+            i != VIR_CGROUP_CONTROLLER_CPUSET)
+            continue;
+
         if (!qemuCgroupControllerActive(driver, i))
             continue;
         rc = virCgroupMoveTask(cgroup, cgroup_emulator, i);
diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index 48cba93..532e704 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -884,8 +884,7 @@ int virCgroupMoveTask(virCgroupPtr src_group, virCgroupPtr dest_group,
 
     if (!src_group->controllers[controller].mountPoint ||
         !dest_group->controllers[controller].mountPoint) {
-        VIR_WARN("no vm cgroup in controller %d", controller);
-        return 0;
+        return -EINVAL;
     }
 
     rc = virCgroupGetValueStr(src_group, controller, "tasks", &content);
-- 
1.7.11.7