[libvirt] [PATCH 2/9] vircgroup: add assertion to allow cgroup controllers to stay empty
When using a hierarchy of cgroups we might want to add tasks just to
the children cgroups but never to the parent. To make sure we do not
use a parent cgroup by accident add a mechanism that lets us assert
a correct implementation in cases we want such a hierarchy.
i.e. for qemu cpusets we want all tasks in /vcpuX or /emulator, not
in /.
Signed-off-by: Henning Schild <henning.schild(a)siemens.com>
---
src/libvirt_private.syms | 2 ++
src/util/vircgroup.c | 19 +++++++++++++++++++
src/util/vircgroup.h | 3 +++
src/util/vircgrouppriv.h | 1 +
4 files changed, 25 insertions(+)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 83f6e2c..cf93d06 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1201,6 +1201,7 @@ virCgroupDenyDeviceMajor;
virCgroupDenyDevicePath;
virCgroupDetectMountsFromFile;
virCgroupFree;
+virCgroupGetAssertEmpty;
virCgroupGetBlkioDeviceReadBps;
virCgroupGetBlkioDeviceReadIops;
virCgroupGetBlkioDeviceWeight;
@@ -1245,6 +1246,7 @@ virCgroupNewThread;
virCgroupPathOfController;
virCgroupRemove;
virCgroupRemoveRecursively;
+virCgroupSetAssertEmpty;
virCgroupSetBlkioDeviceReadBps;
virCgroupSetBlkioDeviceReadIops;
virCgroupSetBlkioDeviceWeight;
diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index 0b65238..ad46dfc 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -1197,6 +1197,15 @@ virCgroupAddTaskController(virCgroupPtr group, pid_t pid, int
controller)
return -1;
}
+ if(group->assert_empty & (1 << controller)) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Controller '%s' is not supposed to contain
any"
+ " tasks. group=%s pid=%d\n"),
+ virCgroupControllerTypeToString(controller),
+ group->path, pid);
+ return -1;
+ }
+
return virCgroupSetValueU64(group, controller, "tasks",
(unsigned long long)pid);
}
@@ -1246,6 +1255,16 @@ virCgroupAddTaskStrController(virCgroupPtr group,
return rc;
}
+void
+virCgroupSetAssertEmpty(virCgroupPtr group, int mask) {
+ group->assert_empty = mask;
+}
+
+int
+virCgroupGetAssertEmpty(virCgroupPtr group) {
+ return group->assert_empty;
+}
+
/**
* virCgroupMoveTask:
diff --git a/src/util/vircgroup.h b/src/util/vircgroup.h
index 63a9e1c..f244c24 100644
--- a/src/util/vircgroup.h
+++ b/src/util/vircgroup.h
@@ -131,6 +131,9 @@ int virCgroupAddTaskController(virCgroupPtr group,
pid_t pid,
int controller);
+void virCgroupSetAssertEmpty(virCgroupPtr group, int mask);
+int virCgroupGetAssertEmpty(virCgroupPtr group);
+
int virCgroupMoveTask(virCgroupPtr src_group,
virCgroupPtr dest_group);
diff --git a/src/util/vircgrouppriv.h b/src/util/vircgrouppriv.h
index 722863e..944d6ae 100644
--- a/src/util/vircgrouppriv.h
+++ b/src/util/vircgrouppriv.h
@@ -44,6 +44,7 @@ struct virCgroupController {
struct virCgroup {
char *path;
+ int assert_empty;
struct virCgroupController controllers[VIR_CGROUP_CONTROLLER_LAST];
};
--
2.4.10