From 7f37afa8924f081f045fb3c0f599053ffdd2c977 Mon Sep 17 00:00:00 2001
From: Boris Popovschi <zyqsempai@mail.ru>
Date: Tue, 25 Feb 2020 14:50:55 +0200
Subject: [PATCH] Added HugeTlb controller for cgroupv2

Signed-off-by: Boris Popovschi <zyqsempai@mail.ru>
---
 libcontainer/cgroups/fs2/fs2.go     | 12 ++++++++
 libcontainer/cgroups/fs2/hugetlb.go | 46 +++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 libcontainer/cgroups/fs2/hugetlb.go

diff --git a/libcontainer/cgroups/fs2/fs2.go b/libcontainer/cgroups/fs2/fs2.go
index 4bb7091a..069ff235 100644
--- a/libcontainer/cgroups/fs2/fs2.go
+++ b/libcontainer/cgroups/fs2/fs2.go
@@ -124,6 +124,12 @@ func (m *manager) GetStats() (*cgroups.Stats, error) {
 			errs = append(errs, err)
 		}
 	}
+	// hugetlb (since kernel 5.6)
+	if _, ok := m.controllers["hugetlb"]; ok {
+		if err := statHugeTlb(m.dirPath, &st, m.config); err != nil {
+			errs = append(errs, err)
+		}
+	}
 	if len(errs) > 0 && !m.rootless {
 		return &st, errors.Errorf("error while statting cgroup v2: %+v", errs)
 	}
@@ -198,6 +204,12 @@ func (m *manager) Set(container *configs.Config) error {
 			errs = append(errs, err)
 		}
 	}
+	// hugetlb (since kernel 5.6)
+	if _, ok := m.controllers["hugetlb"]; ok {
+		if err := setHugeTlb(m.dirPath, container.Cgroups); err != nil {
+			errs = append(errs, err)
+		}
+	}
 	// freezer (since kernel 5.2, pseudo-controller)
 	if err := setFreezer(m.dirPath, container.Cgroups.Freezer); err != nil {
 		errs = append(errs, err)
diff --git a/libcontainer/cgroups/fs2/hugetlb.go b/libcontainer/cgroups/fs2/hugetlb.go
new file mode 100644
index 00000000..ed51592c
--- /dev/null
+++ b/libcontainer/cgroups/fs2/hugetlb.go
@@ -0,0 +1,46 @@
+// +build linux
+
+package fs2
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
+	"github.com/opencontainers/runc/libcontainer/configs"
+)
+
+func setHugeTlb(dirPath string, cgroup *configs.Cgroup) error {
+	for _, hugetlb := range cgroup.Resources.HugetlbLimit {
+		if err := fscommon.WriteFile(dirPath, strings.Join([]string{"hugetlb", hugetlb.Pagesize, "max"}, "."), strconv.FormatUint(hugetlb.Limit, 10)); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func statHugeTlb(dirPath string, stats *cgroups.Stats, cgroup *configs.Cgroup) error {
+	hugetlbStats := cgroups.HugetlbStats{}
+	for _, entry := range cgroup.Resources.HugetlbLimit {
+		max := strings.Join([]string{"hugetlb", entry.Pagesize, "max"}, ".")
+		value, err := fscommon.GetCgroupParamUint(dirPath, max)
+		if err != nil {
+			return fmt.Errorf("failed to parse %s - %v", max, err)
+		}
+		hugetlbStats.Usage = value
+
+		usage := strings.Join([]string{"hugetlb", entry.Pagesize, "current"}, ".")
+		value, err = fscommon.GetCgroupParamUint(dirPath, usage)
+		if err != nil {
+			return fmt.Errorf("failed to parse %s - %v", usage, err)
+		}
+		hugetlbStats.Usage = value
+
+		stats.HugetlbStats[entry.Pagesize] = hugetlbStats
+	}
+
+	return nil
+}