Re: [libvirt] [PATCH v2.1 02/21] Introduce the function virCgroupMoveTask

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&gt; Signed-off-by: Tang Chen <tangchen(a)cn.fujitsu.com&gt; Signed-off-by: Hu Tao <hutao(a)cn.fujitsu.com&gt; --- 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;

+ + 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);