[libvirt PATCH 05/25] vircgroupv2: properly detect placement of running VM
When libvirtd starts a VM it internally stores a path to the main
cgroup. When we restart libvirtd we should get to the same state.
When we start a VM on host with systemd the cgroup is created for us and
the process is already placed into that cgroup and we detect the path
created by systemd using /proc/$PID/cgroup. After that we create
sub-cgroups and move all threads there.
Once libvirtd is restarted we again detect the cgroup path using
/proc/$PID/cgroup, but in this case we will get a different path because
the main thread was moved to a "emulator" cgroup.
Instead of ignoring the "emulator" directory when validating cgroups
remove it completely when detecting cgroup otherwise cgroups will not
work properly when libvirtd is restarted.
Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com>
---
src/util/vircgroupv2.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/src/util/vircgroupv2.c b/src/util/vircgroupv2.c
index 65f5cc6bd0..fb97b7fd2a 100644
--- a/src/util/vircgroupv2.c
+++ b/src/util/vircgroupv2.c
@@ -122,12 +122,6 @@ virCgroupV2ValidateMachineGroup(virCgroupPtr group,
if (!(tmp = strrchr(group->unified.placement, '/')))
return false;
- if (STREQ(tmp, "/emulator")) {
- *tmp = '\0';
-
- if (!(tmp = strrchr(group->unified.placement, '/')))
- return false;
- }
tmp++;
if (STRNEQ(tmp, partmachinename) &&
@@ -198,6 +192,9 @@ virCgroupV2DetectPlacement(virCgroupPtr group,
const char *controllers,
const char *selfpath)
{
+ g_autofree char *placement = g_strdup(selfpath);
+ char *tmp = NULL;
+
if (group->unified.placement)
return 0;
@@ -208,12 +205,18 @@ virCgroupV2DetectPlacement(virCgroupPtr group,
if (STRNEQ(controllers, ""))
return 0;
+ /* Running VM will have the main thread placed in emulator cgroup
+ * but we need to get the main cgroup. */
+ tmp = g_strrstr(placement, "/emulator");
+ if (tmp)
+ *tmp = '\0';
+
/*
* selfpath == "/" + path="" -> "/"
* selfpath == "/libvirt.service" + path == "" ->
"/libvirt.service"
* selfpath == "/libvirt.service" + path == "foo" ->
"/libvirt.service/foo"
*/
- group->unified.placement = g_strdup_printf("%s%s%s", selfpath,
+ group->unified.placement = g_strdup_printf("%s%s%s", placement,
(STREQ(selfpath, "/") ||
STREQ(path, "") ? "" : "/"), path);
return 0;
--
2.26.2