[libvirt] [PATCH v2 6/6] util: vircgroupv2: don't error out if enabling controller fails

[Pavel Hrdina]

Currently CPU controller cannot be enabled if there is any real-time
task running and is assigned to non-root cgroup which is the case on
several distributions with graphical environment.

Instead of erroring out treat it as the controller is not available.

Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
---

Changes in v2:
    - Reworked error reporting to virResetLastError only if we fail
      to enable controller.  The error message will be still logged
      but now it's more descriptive what have failed.

 src/util/vircgroupv2.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/util/vircgroupv2.c b/src/util/vircgroupv2.c
index 133a8e0e66..348c12d5c6 100644
--- a/src/util/vircgroupv2.c
+++ b/src/util/vircgroupv2.c
@@ -433,6 +433,8 @@ virCgroupV2MakeGroup(virCgroupPtr parent ATTRIBUTE_UNUSED,
         } else {
             size_t i;
             for (i = 0; i < VIR_CGROUP_CONTROLLER_LAST; i++) {
+                int rc;
+
                 if (!virCgroupV2HasController(parent, i))
                     continue;
 
@@ -440,8 +442,17 @@ virCgroupV2MakeGroup(virCgroupPtr parent ATTRIBUTE_UNUSED,
                 if (i == VIR_CGROUP_CONTROLLER_CPUACCT)
                     continue;
 
-                if (virCgroupV2EnableController(parent, i) < 0)
+                rc = virCgroupV2EnableController(parent, i);
+                if (rc < 0) {
+                    if (rc == -2) {
+                        virResetLastError();
+                        VIR_DEBUG("failed to enable '%s' controller, skipping",
+                                  virCgroupV2ControllerTypeToString(i));
+                        group->unified.controllers &= ~(1 << i);
+                        continue;
+                    }
                     return -1;
+                }
             }
         }
     }
-- 
2.21.0