Merge pull request #3374 from giuseppe/cgroups

cgroups: add initial support for cgroups v2

1 files changed, 66 insertions, 0 deletions

diff --git a/pkg/cgroups/pids.go b/pkg/cgroups/pids.go
new file mode 100644
index 000000000..c90dc1c02
--- /dev/null
+++ b/pkg/cgroups/pids.go
@@ -0,0 +1,66 @@
+package cgroups
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	spec "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+type pidHandler struct {
+}
+
+func getPidsHandler() *pidHandler {
+	return &pidHandler{}
+}
+
+// Apply set the specified constraints
+func (c *pidHandler) Apply(ctr *CgroupControl, res *spec.LinuxResources) error {
+	if res.Pids == nil {
+		return nil
+	}
+	var PIDRoot string
+
+	if ctr.cgroup2 {
+		PIDRoot = filepath.Join(cgroupRoot, ctr.path)
+	} else {
+		PIDRoot = ctr.getCgroupv1Path(Pids)
+	}
+
+	p := filepath.Join(PIDRoot, "pids.max")
+	return ioutil.WriteFile(p, []byte(fmt.Sprintf("%d\n", res.Pids.Limit)), 0644)
+}
+
+// Create the cgroup
+func (c *pidHandler) Create(ctr *CgroupControl) (bool, error) {
+	if ctr.cgroup2 {
+		return false, fmt.Errorf("pid create not implemented for cgroup v2")
+	}
+	return ctr.createCgroupDirectory(Pids)
+}
+
+// Destroy the cgroup
+func (c *pidHandler) Destroy(ctr *CgroupControl) error {
+	return os.Remove(ctr.getCgroupv1Path(Pids))
+}
+
+// Stat fills a metrics structure with usage stats for the controller
+func (c *pidHandler) Stat(ctr *CgroupControl, m *Metrics) error {
+	var PIDRoot string
+
+	if ctr.cgroup2 {
+		PIDRoot = filepath.Join(cgroupRoot, ctr.path)
+	} else {
+		PIDRoot = ctr.getCgroupv1Path(Pids)
+	}
+
+	current, err := readFileAsUint64(filepath.Join(PIDRoot, "pids.current"))
+	if err != nil {
+		return err
+	}
+
+	m.Pids = PidsMetrics{Current: current}
+	return nil
+}