From ff16bde100e19fbff17a964c08321f30f87afb22 Mon Sep 17 00:00:00 2001
From: Henning Schild <henning.schild@siemens.com>
Date: Fri, 26 Feb 2016 16:34:24 +0100
Subject: [PATCH] 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 |   1 -
 src/qemu/qemu_process.c  |   2 +-
 src/util/vircgroup.c     | 103 ---------------------------------------
 src/util/vircgroup.h     |   3 --
 4 files changed, 1 insertion(+), 108 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 4c53bf42a0..5251dc0bc9 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1231,7 +1231,6 @@ virCgroupHasEmptyTasks;
 virCgroupKill;
 virCgroupKillPainfully;
 virCgroupKillRecursive;
-virCgroupMoveTask;
 virCgroupNewDetect;
 virCgroupNewDetectMachine;
 virCgroupNewDomainPartition;
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index fa2bdb834e..13813131f2 100644
--- a/src/qemu/qemu_process.c
+++ b/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;
 
 
diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index 706d27cec3..bffd88f90a 100644
--- a/src/util/vircgroup.c
+++ b/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,
diff --git a/src/util/vircgroup.h b/src/util/vircgroup.h
index 7914cbbdaa..2ddbb350f1 100644
--- a/src/util/vircgroup.h
+++ b/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);