support cgroup2

* only shim v2 runc v2 ("io.containerd.runc.v2") is supported
* only PID metrics is implemented. Others should be implemented in separate PRs.
* lots of code duplication in v1 metrics and v2 metrics. Dedupe should be separate PR.

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

vendor/github.com/cilium/ebpf/asm/jump_string.go

@@ -0,0 +1,53 @@
+// Code generated by "stringer -output jump_string.go -type=JumpOp"; DO NOT EDIT.
+
+package asm
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidJumpOp-255]
+	_ = x[Ja-0]
+	_ = x[JEq-16]
+	_ = x[JGT-32]
+	_ = x[JGE-48]
+	_ = x[JSet-64]
+	_ = x[JNE-80]
+	_ = x[JSGT-96]
+	_ = x[JSGE-112]
+	_ = x[Call-128]
+	_ = x[Exit-144]
+	_ = x[JLT-160]
+	_ = x[JLE-176]
+	_ = x[JSLT-192]
+	_ = x[JSLE-208]
+}
+
+const _JumpOp_name = "JaJEqJGTJGEJSetJNEJSGTJSGECallExitJLTJLEJSLTJSLEInvalidJumpOp"
+
+var _JumpOp_map = map[JumpOp]string{
+	0:   _JumpOp_name[0:2],
+	16:  _JumpOp_name[2:5],
+	32:  _JumpOp_name[5:8],
+	48:  _JumpOp_name[8:11],
+	64:  _JumpOp_name[11:15],
+	80:  _JumpOp_name[15:18],
+	96:  _JumpOp_name[18:22],
+	112: _JumpOp_name[22:26],
+	128: _JumpOp_name[26:30],
+	144: _JumpOp_name[30:34],
+	160: _JumpOp_name[34:37],
+	176: _JumpOp_name[37:40],
+	192: _JumpOp_name[40:44],
+	208: _JumpOp_name[44:48],
+	255: _JumpOp_name[48:61],
+}
+
+func (i JumpOp) String() string {
+	if str, ok := _JumpOp_map[i]; ok {
+		return str
+	}
+	return "JumpOp(" + strconv.FormatInt(int64(i), 10) + ")"
+}