Remove per-container CGroup parents

Originally, it seemed like a good idea to place Conmon and the
container it managed under a shared CGroup, so we could manage
the two together. It's become increasingly clear that this is a
potential performance sore point, gains us little practical
benefit in managing Conmon, and adds extra steps to container
cleanup that interfere with Conmon postrun hooks.

Revert back to a shared CGroup for conmon processes under the
CGroup parent. This will retain per-pod conmon CGroups as well if
the pod is set to create a CGroup and act as CGroup parent for
its containers.

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

Closes: #1051
Approved by: umohnani8

1 files changed, 0 insertions, 43 deletions

diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 327c78045..0dc02d117 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -6,12 +6,10 @@ import (
 	"context"
 	"fmt"
 	"path"
-	"path/filepath"
 	"strings"
 	"syscall"
 	"time"
 
-	"github.com/containerd/cgroups"
 	"github.com/containers/storage/pkg/idtools"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/opencontainers/runtime-tools/generate"
@@ -24,47 +22,6 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-// cleanupCgroup cleans up residual CGroups after container execution
-// This is a no-op for the systemd cgroup driver
-func (c *Container) cleanupCgroups() error {
-	if !c.state.CgroupCreated {
-		logrus.Debugf("Cgroups are not present, ignoring...")
-		return nil
-	}
-
-	if c.runtime.config.CgroupManager == SystemdCgroupsManager {
-		return nil
-	}
-
-	// Remove the base path of the container's cgroups
-	path := filepath.Join(c.config.CgroupParent, fmt.Sprintf("libpod-%s", c.ID()))
-
-	logrus.Debugf("Removing CGroup %s", path)
-
-	cgroup, err := cgroups.Load(cgroups.V1, cgroups.StaticPath(path))
-	if err != nil {
-		// It's fine for the cgroup to not exist
-		// We want it gone, it's gone
-		if err == cgroups.ErrCgroupDeleted {
-			return nil
-		}
-
-		return err
-	}
-
-	if err := cgroup.Delete(); err != nil {
-		return err
-	}
-
-	c.state.CgroupCreated = false
-
-	if c.valid {
-		return c.save()
-	}
-
-	return nil
-}
-
 func (c *Container) mountSHM(shmOptions string) error {
 	if err := unix.Mount("shm", c.config.ShmDir, "tmpfs", unix.MS_NOEXEC|unix.MS_NOSUID|unix.MS_NODEV,
 		label.FormatMountLabel(shmOptions, c.config.MountLabel)); err != nil {