[libvirt] [PATCH] Temporarily shutoff CPUSET cgroup in libvirt.

[Tang Chen]

When a cpu or memory is offlined and onlined again, cgroup will not
recover any corresponding values. This is a problem in kernel.
Do not use CPUSET cgroup to limit threads using cpu and memory until
the problem is fixed in kernel.

Signed-off-by: Tang Chen <tangchen at cn.fujitsu.com>
---
 src/qemu/qemu.conf   |    5 ++++-
 src/qemu/qemu_conf.c |    7 ++++++-
 src/util/cgroup.c    |    3 +--
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf
index 18105ca..6bf7290 100644
--- a/src/qemu/qemu.conf
+++ b/src/qemu/qemu.conf
@@ -211,7 +211,10 @@
 # can be mounted in different locations. libvirt will detect
 # where they are located.
 #
-#cgroup_controllers = [ "cpu", "devices", "memory", "blkio", "cpuset", "cpuacct" ]
+# When a cpu or memory is offlined and onlined again, cgroup will not
+# recover any corresponding values. This is a problem in kernel.
+# So DO NOT use cpuset cgroup until this problem is fixed in kernel.
+#cgroup_controllers = [ "cpu", "devices", "memory", "blkio", "cpuacct" ]
 
 # This is the basic set of devices allowed / required by
 # all virtual machines.
diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index 91a56f1..80b0787 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -397,12 +397,17 @@ int qemudLoadDriverConfig(struct qemud_driver *driver,
             driver->cgroupControllers |= (1 << ctl);
         }
     } else {
+        /*
+         * When a cpu or memory is offlined and onlined again, cgroup will not
+         * recover any corresponding values. This is a problem in kernel.
+         * Do not use CPUSET cgroup to limit threads using cpu and memory until
+         * the problem is fixed in kernel.
+         */
         driver->cgroupControllers =
             (1 << VIR_CGROUP_CONTROLLER_CPU) |
             (1 << VIR_CGROUP_CONTROLLER_DEVICES) |
             (1 << VIR_CGROUP_CONTROLLER_MEMORY) |
             (1 << VIR_CGROUP_CONTROLLER_BLKIO) |
-            (1 << VIR_CGROUP_CONTROLLER_CPUSET) |
             (1 << VIR_CGROUP_CONTROLLER_CPUACCT);
     }
     for (i = 0 ; i < VIR_CGROUP_CONTROLLER_LAST ; i++) {
diff --git a/src/util/cgroup.c b/src/util/cgroup.c
index 5dc0764..cd7d3fe 100644
--- a/src/util/cgroup.c
+++ b/src/util/cgroup.c
@@ -543,8 +543,7 @@ static int virCgroupMakeGroup(virCgroupPtr parent, virCgroupPtr group,
         /* We need to control cpu bandwidth for each vcpu now */
         if ((flags & VIR_CGROUP_VCPU) &&
             (i != VIR_CGROUP_CONTROLLER_CPU &&
-             i != VIR_CGROUP_CONTROLLER_CPUACCT &&
-             i != VIR_CGROUP_CONTROLLER_CPUSET)) {
+             i != VIR_CGROUP_CONTROLLER_CPUACCT)) {
             /* treat it as unmounted and we can use virCgroupAddTask */
             VIR_FREE(group->controllers[i].mountPoint);
             continue;
-- 
1.7.10.1