Merge pull request #3374 from giuseppe/cgroups

cgroups: add initial support for cgroups v2

1 files changed, 67 insertions, 0 deletions

diff --git a/pkg/cgroups/memory.go b/pkg/cgroups/memory.go
new file mode 100644
index 000000000..0505eac40
--- /dev/null
+++ b/pkg/cgroups/memory.go
@@ -0,0 +1,67 @@
+package cgroups
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	spec "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+type memHandler struct {
+}
+
+func getMemoryHandler() *memHandler {
+	return &memHandler{}
+}
+
+// Apply set the specified constraints
+func (c *memHandler) Apply(ctr *CgroupControl, res *spec.LinuxResources) error {
+	if res.Memory == nil {
+		return nil
+	}
+	return fmt.Errorf("memory apply not implemented yet")
+}
+
+// Create the cgroup
+func (c *memHandler) Create(ctr *CgroupControl) (bool, error) {
+	if ctr.cgroup2 {
+		return false, fmt.Errorf("memory create not implemented for cgroup v2")
+	}
+	return ctr.createCgroupDirectory(Memory)
+}
+
+// Destroy the cgroup
+func (c *memHandler) Destroy(ctr *CgroupControl) error {
+	return os.Remove(ctr.getCgroupv1Path(Memory))
+}
+
+// Stat fills a metrics structure with usage stats for the controller
+func (c *memHandler) Stat(ctr *CgroupControl, m *Metrics) error {
+	var err error
+	usage := MemoryUsage{}
+
+	var memoryRoot string
+	filenames := map[string]string{}
+
+	if ctr.cgroup2 {
+		memoryRoot = filepath.Join(cgroupRoot, ctr.path)
+		filenames["usage"] = "memory.current"
+		filenames["limit"] = "memory.max"
+	} else {
+		memoryRoot = ctr.getCgroupv1Path(Memory)
+		filenames["usage"] = "memory.usage_in_bytes"
+		filenames["limit"] = "memory.limit_in_bytes"
+	}
+	usage.Usage, err = readFileAsUint64(filepath.Join(memoryRoot, filenames["usage"]))
+	if err != nil {
+		return err
+	}
+	usage.Limit, err = readFileAsUint64(filepath.Join(memoryRoot, filenames["limit"]))
+	if err != nil {
+		return err
+	}
+
+	m.Memory = MemoryMetrics{Usage: usage}
+	return nil
+}