4:13 a.m.
Introduce a new API to move tasks of one controller from a cgroup to another cgroup
Signed-off-by: Wen Congyang <wency(a)cn.fujitsu.com>
---
src/libvirt_private.syms | 2 +
src/util/cgroup.c | 127 ++++++++++++++++++++++++++++++++++++++++++++++
src/util/cgroup.h | 8 +++
3 files changed, 137 insertions(+)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 8925267..812cf1d 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -60,6 +60,7 @@ virCapabilitiesSetMacPrefix;
# cgroup.h
virCgroupAddTask;
+virCgroupAddTaskController;
virCgroupAllowDeviceMajor;
virCgroupAllowDevicePath;
virCgroupControllerTypeFromString;
@@ -88,6 +89,7 @@ virCgroupKill;
virCgroupKillPainfully;
virCgroupKillRecursive;
virCgroupMounted;
+virCgroupMoveTask;
virCgroupPathOfController;
virCgroupRemove;
virCgroupSetBlkioDeviceWeight;
diff --git a/src/util/cgroup.c b/src/util/cgroup.c
index 1ac8278..3e9ba4e 100644
--- a/src/util/cgroup.c
+++ b/src/util/cgroup.c
@@ -791,6 +791,133 @@ int virCgroupAddTask(virCgroupPtr group, pid_t pid)
return rc;
}
+/**
+ * virCgroupAddTaskController:
+ *
+ * @group: The cgroup to add a task to
+ * @pid: The pid of the task to add
+ * @controller: The cgroup controller to be operated on
+ *
+ * Returns: 0 on success or -errno on failure
+ */
+int virCgroupAddTaskController(virCgroupPtr group, pid_t pid, int controller)
+{
+ int rc = 0;
+
+ if (controller < VIR_CGROUP_CONTROLLER_CPU ||
+ controller > VIR_CGROUP_CONTROLLER_BLKIO)
+ return -EINVAL;
+
+ if (!group->controllers[controller].mountPoint)
+ return -EINVAL;
+
+ return virCgroupSetValueU64(group, controller, "tasks",
+ (unsigned long long)pid);
+}
+
+static int virCgroupAddTaskStr(virCgroupPtr group, const char *pidstr)
+{
+ unsigned long long value;
+
+ if (virStrToLong_ull(pidstr, NULL, 10, &value) < 0)
+ return -EINVAL;
+
+ return virCgroupAddTask(group, value);
+}
+
+static int virCgroupAddTaskStrController(virCgroupPtr group,
+ const char *pidstr,
+ int controller)
+{
+ char *str = NULL, *cur = NULL, *next = NULL;
+ unsigned long long pid = 0;
+ int len = 0, rc = 0;
+
+ len = strlen(pidstr);
+ VIR_ALLOC_N(str, len);
+ if (str == NULL) {
+ VIR_ERROR(_("No more memory."));
+ return -1;
+ }
+ rc = strcpy(str, pidstr);
+ if (rc != 0)
+ return rc;
+
+ cur = str;
+ while ((next = strchr(cur, '\n')) != NULL) {
+ *next = '\0';
+ rc = virStrToLong_ull(cur, NULL, 10, &pid);
+ if (rc != 0)
+ goto cleanup;
+ cur = next + 1;
+
+ rc = virCgroupAddTaskController(group, pid, controller);
+ if (rc != 0)
+ goto cleanup;
+ }
+ if (cur != '\0') {
+ rc = virStrToLong_ull(cur, NULL, 10, &pid);
+ if (rc != 0)
+ goto cleanup;
+ rc = virCgroupAddTaskController(group, pid, controller);
+ if (rc != 0)
+ goto cleanup;
+ }
+
+cleanup:
+ VIR_FREE(str);
+ return rc;
+}
+
+/**
+ * virCgroupMoveTask:
+ *
+ * @src_group: The source cgroup where all tasks are removed from
+ * @dest_group: The destination where all tasks are added to
+ * @controller: The cgroup controller to be operated on
+ *
+ * Returns: 0 on success or -errno on failure
+ */
+int virCgroupMoveTask(virCgroupPtr src_group, virCgroupPtr dest_group,
+ int controller)
+{
+ int rc = 0, err = 0;
+ char *content = NULL;
+
+ if (controller < VIR_CGROUP_CONTROLLER_CPU ||
+ controller > VIR_CGROUP_CONTROLLER_BLKIO)
+ return -EINVAL;
+
+ if (!src_group->controllers[controller].mountPoint ||
+ !dest_group->controllers[controller].mountPoint)
+ return -EINVAL;
+
+ rc = virCgroupGetValueStr(src_group, controller, "tasks", &content);
+ if (rc != 0)
+ return rc;
+
+ rc = virCgroupAddTaskStrController(dest_group, content, controller);
+ if (rc != 0)
+ goto cleanup;
+
+ VIR_FREE(content);
+
+ return 0;
+
+cleanup:
+ /*
+ * We don't need to recover dest_cgroup because cgroup will make sure
+ * that one task only resides in one cgroup of the same controller.
+ */
+ err = virCgroupAddTaskStrController(src_group, content, controller);
+ if (err != 0)
+ VIR_ERROR(_("Cannot recover cgroup %s from %s"),
+ src_group->controllers[controller].mountPoint,
+ dest_group->controllers[controller].mountPoint);
+ VIR_FREE(content);
+
+ return rc;
+}
/**
* virCgroupForDriver:
diff --git a/src/util/cgroup.h b/src/util/cgroup.h
index 315ebd6..f14c167 100644
--- a/src/util/cgroup.h
+++ b/src/util/cgroup.h
@@ -58,6 +58,14 @@ int virCgroupPathOfController(virCgroupPtr group,
int virCgroupAddTask(virCgroupPtr group, pid_t pid);
+int virCgroupAddTaskController(virCgroupPtr group,
+ pid_t pid,
+ int controller);
+
+int virCgroupMoveTask(virCgroupPtr src_group,
+ virCgroupPtr dest_group,
+ int controller);
+
int virCgroupSetBlkioWeight(virCgroupPtr group, unsigned int weight);
int virCgroupGetBlkioWeight(virCgroupPtr group, unsigned int *weight);
--
1.7.10.2