On Tue, Aug 21, 2012 at 05:18:25PM +0800, Hu Tao wrote:
> Introduce a new API to move tasks of one controller from a cgroup to another cgroup
>
> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
> Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> Signed-off-by: Hu Tao <hutao@xxxxxxxxxxxxxx>
> ---
> src/libvirt_private.syms | 2 +
> src/util/cgroup.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++
> src/util/cgroup.h | 8 ++++
> 3 files changed, 120 insertions(+)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 6e834fe..0b0a70d 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -60,6 +60,7 @@ virCapabilitiesSetMacPrefix;
>
> # cgroup.h
> virCgroupAddTask;
> +virCgroupAddTaskController;
> virCgroupAllowDevice;
> virCgroupAllowDeviceMajor;
> virCgroupAllowDevicePath;
> @@ -91,6 +92,7 @@ virCgroupKill;
> virCgroupKillPainfully;
> virCgroupKillRecursive;
> virCgroupMounted;
> +virCgroupMoveTask;
> virCgroupPathOfController;
> virCgroupRemove;
> virCgroupSetBlkioDeviceWeight;
> diff --git a/src/util/cgroup.c b/src/util/cgroup.c
> index 169b56a..24e08b4 100644
> --- a/src/util/cgroup.c
> +++ b/src/util/cgroup.c
> @@ -802,6 +802,116 @@ 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)
> +{
> + if (controller < VIR_CGROUP_CONTROLLER_CPU ||
> + controller > VIR_CGROUP_CONTROLLER_BLKIO)
> + return -EINVAL;
This conditional should really be
if (controller < 0 || controller >= VIR_CGROUP_CONTROLLER_LAST)
> +
> + if (!group->controllers[controller].mountPoint)
> + return -EINVAL;
> +
> + return virCgroupSetValueU64(group, controller, "tasks",
> + (unsigned long long)pid);
> +}
> +
> +
> +static int virCgroupAddTaskStrController(virCgroupPtr group,
> + const char *pidstr,
> + int controller)
> +{
> + char *str = NULL, *cur = NULL, *next = NULL;
> + unsigned long long p = 0;
> + int rc = 0;
> + char *endp;
> +
> + if (virAsprintf(&str, "%s", pidstr) < 0)
> + return -1;
> +
> + cur = str;
> + while (*cur != '\0') {
> + rc = virStrToLong_ull(cur, &endp, 10, &p);
> + if (rc != 0)
> + goto cleanup;
> +
> + rc = virCgroupAddTaskController(group, p, controller);
> + if (rc != 0)
> + goto cleanup;
> +
> + next = strchr(cur, '\n');
> + if (next) {
> + cur = next + 1;
> + *next = '\0';
> + } else {
> + break;
> + }
> + }
> +
> +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) {
> + VIR_WARN("no vm cgroup in controller %d", controller);
> + return 0;
> + }
> +
> + 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 9f803a5..727e536 100644
> --- a/src/util/cgroup.h
> +++ b/src/util/cgroup.h
> @@ -70,6 +70,14 @@ 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);
ACK
Daniel
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