qemu_cgroup: use virCgroupAddTask instead of virCgroupMoveTask

qemuProcessSetupEmulator runs at a point in time where there is only
the qemu main thread. Use virCgroupAddTask to put just that one task
into the emulator cgroup. That patch makes virCgroupMoveTask and
virCgroupAddTaskStrController obsolete.

Signed-off-by: Henning Schild <henning.schild@siemens.com>

src/libvirt_private.syms

@@ -1231,7 +1231,6 @@ virCgroupHasEmptyTasks;
 virCgroupKill;
 virCgroupKillPainfully;
 virCgroupKillRecursive;
-virCgroupMoveTask;
 virCgroupNewDetect;
 virCgroupNewDetectMachine;
 virCgroupNewDomainPartition;

src/qemu/qemu_process.c

@@ -2220,7 +2220,7 @@ qemuProcessSetupEmulator(virDomainObjPtr vm)
                                true, &cgroup_emulator) < 0)
             goto cleanup;
 
-        if (virCgroupMoveTask(priv->cgroup, cgroup_emulator) < 0)
+        if (virCgroupAddTask(cgroup_emulator, vm->pid) < 0)
             goto cleanup;
 
 

src/util/vircgroup.c

@@ -1223,99 +1223,6 @@ virCgroupAddTaskController(virCgroupPtr group, pid_t pid, int controller)
 }
 
 
-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 (VIR_STRDUP(str, pidstr) < 0)
-        return -1;
-
-    cur = str;
-    while (*cur != '\0') {
-        if (virStrToLong_ull(cur, &endp, 10, &p) < 0) {
-            virReportError(VIR_ERR_INTERNAL_ERROR,
-                           _("Cannot parse '%s' as an integer"), cur);
-            goto cleanup;
-        }
-
-        if (virCgroupAddTaskController(group, p, controller) < 0) {
-            /* A thread that exits between when we first read the source
-             * tasks and now is not fatal.  */
-            if (virLastErrorIsSystemErrno(ESRCH))
-                virResetLastError();
-            else
-                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
- *
- * Returns: 0 on success or -1 on failure
- */
-int
-virCgroupMoveTask(virCgroupPtr src_group, virCgroupPtr dest_group)
-{
-    int ret = -1;
-    char *content = NULL;
-    size_t i;
-
-    for (i = 0; i < VIR_CGROUP_CONTROLLER_LAST; i++) {
-        if (!src_group->controllers[i].mountPoint ||
-            !dest_group->controllers[i].mountPoint)
-            continue;
-
-        /* We must never move tasks in systemd's hierarchy */
-        if (i == VIR_CGROUP_CONTROLLER_SYSTEMD)
-            continue;
-
-        /* New threads are created in the same group as their parent;
-         * but if a thread is created after we first read we aren't
-         * aware that it needs to move.  Therefore, we must iterate
-         * until content is empty.  */
-        while (1) {
-            VIR_FREE(content);
-            if (virCgroupGetValueStr(src_group, i, "tasks", &content) < 0)
-                return -1;
-
-            if (!*content)
-                break;
-
-            if (virCgroupAddTaskStrController(dest_group, content, i) < 0)
-                goto cleanup;
-        }
-    }
-
-    ret = 0;
- cleanup:
-    VIR_FREE(content);
-    return ret;
-}
-
-
 static int
 virCgroupSetPartitionSuffix(const char *path, char **res)
 {
@@ -4324,16 +4231,6 @@ virCgroupAddTaskController(virCgroupPtr group ATTRIBUTE_UNUSED,
 }
 
 
-int
-virCgroupMoveTask(virCgroupPtr src_group ATTRIBUTE_UNUSED,
-                  virCgroupPtr dest_group ATTRIBUTE_UNUSED)
-{
-    virReportSystemError(ENXIO, "%s",
-                         _("Control groups not supported on this platform"));
-    return -1;
-}
-
-
 int
 virCgroupGetBlkioIoServiced(virCgroupPtr group ATTRIBUTE_UNUSED,
                             long long *bytes_read ATTRIBUTE_UNUSED,

src/util/vircgroup.h

@@ -132,9 +132,6 @@ int virCgroupAddTaskController(virCgroupPtr group,
                                pid_t pid,
                                int controller);
 
-int virCgroupMoveTask(virCgroupPtr src_group,
-                      virCgroupPtr dest_group);
-
 int virCgroupSetBlkioWeight(virCgroupPtr group, unsigned int weight);
 int virCgroupGetBlkioWeight(virCgroupPtr group, unsigned int *weight);