libct/cg: support hugetlb rsvd

This adds support for hugetlb.<pagesize>.rsvd limiting and accounting.

Signed-off-by: Kir Kolyshkin <[email protected]>

libcontainer/cgroups/fs/hugetlb.go

@@ -1,6 +1,8 @@
 package fs
 
 import (
+	"errors"
+	"os"
 	"strconv"
 
 	"github.com/opencontainers/runc/libcontainer/cgroups"
@@ -19,8 +21,23 @@ func (s *HugetlbGroup) Apply(path string, _ *configs.Resources, pid int) error {
 }
 
 func (s *HugetlbGroup) Set(path string, r *configs.Resources) error {
+	const suffix = ".limit_in_bytes"
+	skipRsvd := false
+
 	for _, hugetlb := range r.HugetlbLimit {
-		if err := cgroups.WriteFile(path, "hugetlb."+hugetlb.Pagesize+".limit_in_bytes", strconv.FormatUint(hugetlb.Limit, 10)); err != nil {
+		prefix := "hugetlb." + hugetlb.Pagesize
+		val := strconv.FormatUint(hugetlb.Limit, 10)
+		if err := cgroups.WriteFile(path, prefix+suffix, val); err != nil {
+			return err
+		}
+		if skipRsvd {
+			continue
+		}
+		if err := cgroups.WriteFile(path, prefix+".rsvd"+suffix, val); err != nil {
+			if errors.Is(err, os.ErrNotExist) {
+				skipRsvd = true
+				continue
+			}
 			return err
 		}
 	}
@@ -32,24 +49,29 @@ func (s *HugetlbGroup) GetStats(path string, stats *cgroups.Stats) error {
 	if !cgroups.PathExists(path) {
 		return nil
 	}
+	rsvd := ".rsvd"
 	hugetlbStats := cgroups.HugetlbStats{}
 	for _, pageSize := range cgroups.HugePageSizes() {
-		usage := "hugetlb." + pageSize + ".usage_in_bytes"
-		value, err := fscommon.GetCgroupParamUint(path, usage)
+	again:
+		prefix := "hugetlb." + pageSize + rsvd
+
+		value, err := fscommon.GetCgroupParamUint(path, prefix+".usage_in_bytes")
 		if err != nil {
+			if rsvd != "" && errors.Is(err, os.ErrNotExist) {
+				rsvd = ""
+				goto again
+			}
 			return err
 		}
 		hugetlbStats.Usage = value
 
-		maxUsage := "hugetlb." + pageSize + ".max_usage_in_bytes"
-		value, err = fscommon.GetCgroupParamUint(path, maxUsage)
+		value, err = fscommon.GetCgroupParamUint(path, prefix+".max_usage_in_bytes")
 		if err != nil {
 			return err
 		}
 		hugetlbStats.MaxUsage = value
 
-		failcnt := "hugetlb." + pageSize + ".failcnt"
-		value, err = fscommon.GetCgroupParamUint(path, failcnt)
+		value, err = fscommon.GetCgroupParamUint(path, prefix+".failcnt")
 		if err != nil {
 			return err
 		}

libcontainer/cgroups/fs/hugetlb_test.go

@@ -21,6 +21,11 @@ const (
 	limit    = "hugetlb.%s.limit_in_bytes"
 	maxUsage = "hugetlb.%s.max_usage_in_bytes"
 	failcnt  = "hugetlb.%s.failcnt"
+
+	rsvdUsage    = "hugetlb.%s.rsvd.usage_in_bytes"
+	rsvdLimit    = "hugetlb.%s.rsvd.limit_in_bytes"
+	rsvdMaxUsage = "hugetlb.%s.rsvd.max_usage_in_bytes"
+	rsvdFailcnt  = "hugetlb.%s.rsvd.failcnt"
 )
 
 func TestHugetlbSetHugetlb(t *testing.T) {
@@ -52,13 +57,15 @@ func TestHugetlbSetHugetlb(t *testing.T) {
 	}
 
 	for _, pageSize := range cgroups.HugePageSizes() {
-		limit := fmt.Sprintf(limit, pageSize)
-		value, err := fscommon.GetCgroupParamUint(path, limit)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if value != hugetlbAfter {
-			t.Fatalf("Set hugetlb.limit_in_bytes failed. Expected: %v, Got: %v", hugetlbAfter, value)
+		for _, f := range []string{limit, rsvdLimit} {
+			limit := fmt.Sprintf(f, pageSize)
+			value, err := fscommon.GetCgroupParamUint(path, limit)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if value != hugetlbAfter {
+				t.Fatalf("Set %s failed. Expected: %v, Got: %v", limit, hugetlbAfter, value)
+			}
 		}
 	}
 }
@@ -85,6 +92,28 @@ func TestHugetlbStats(t *testing.T) {
 	}
 }
 
+func TestHugetlbRStatsRsvd(t *testing.T) {
+	path := tempDir(t, "hugetlb")
+	for _, pageSize := range cgroups.HugePageSizes() {
+		writeFileContents(t, path, map[string]string{
+			fmt.Sprintf(rsvdUsage, pageSize):    hugetlbUsageContents,
+			fmt.Sprintf(rsvdMaxUsage, pageSize): hugetlbMaxUsageContents,
+			fmt.Sprintf(rsvdFailcnt, pageSize):  hugetlbFailcnt,
+		})
+	}
+
+	hugetlb := &HugetlbGroup{}
+	actualStats := *cgroups.NewStats()
+	err := hugetlb.GetStats(path, &actualStats)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expectedStats := cgroups.HugetlbStats{Usage: 128, MaxUsage: 256, Failcnt: 100}
+	for _, pageSize := range cgroups.HugePageSizes() {
+		expectHugetlbStatEquals(t, expectedStats, actualStats.HugetlbStats[pageSize])
+	}
+}
+
 func TestHugetlbStatsNoUsageFile(t *testing.T) {
 	path := tempDir(t, "hugetlb")
 	writeFileContents(t, path, map[string]string{

libcontainer/cgroups/fs2/hugetlb.go

@@ -1,6 +1,8 @@
 package fs2
 
 import (
+	"errors"
+	"os"
 	"strconv"
 
 	"github.com/opencontainers/runc/libcontainer/cgroups"
@@ -16,8 +18,22 @@ func setHugeTlb(dirPath string, r *configs.Resources) error {
 	if !isHugeTlbSet(r) {
 		return nil
 	}
+	const suffix = ".max"
+	skipRsvd := false
 	for _, hugetlb := range r.HugetlbLimit {
-		if err := cgroups.WriteFile(dirPath, "hugetlb."+hugetlb.Pagesize+".max", strconv.FormatUint(hugetlb.Limit, 10)); err != nil {
+		prefix := "hugetlb." + hugetlb.Pagesize
+		val := strconv.FormatUint(hugetlb.Limit, 10)
+		if err := cgroups.WriteFile(dirPath, prefix+suffix, val); err != nil {
+			return err
+		}
+		if skipRsvd {
+			continue
+		}
+		if err := cgroups.WriteFile(dirPath, prefix+".rsvd"+suffix, val); err != nil {
+			if errors.Is(err, os.ErrNotExist) {
+				skipRsvd = true
+				continue
+			}
 			return err
 		}
 	}
@@ -27,15 +43,21 @@ func setHugeTlb(dirPath string, r *configs.Resources) error {
 
 func statHugeTlb(dirPath string, stats *cgroups.Stats) error {
 	hugetlbStats := cgroups.HugetlbStats{}
+	rsvd := ".rsvd"
 	for _, pagesize := range cgroups.HugePageSizes() {
-		value, err := fscommon.GetCgroupParamUint(dirPath, "hugetlb."+pagesize+".current")
+	again:
+		prefix := "hugetlb." + pagesize + rsvd
+		value, err := fscommon.GetCgroupParamUint(dirPath, prefix+".current")
 		if err != nil {
+			if errors.Is(err, os.ErrNotExist) {
+				rsvd = ""
+				goto again
+			}
 			return err
 		}
 		hugetlbStats.Usage = value
 
-		fileName := "hugetlb." + pagesize + ".events"
-		value, err = fscommon.GetValueByKey(dirPath, fileName, "max")
+		value, err = fscommon.GetValueByKey(dirPath, prefix+".events", "max")
 		if err != nil {
 			return err
 		}

tests/integration/cgroups.bats

@@ -199,6 +199,69 @@ function setup() {
 	check_cgroup_value "cpu.idle" "1"
 }
 
+# Convert size in KB to hugetlb size suffix.
+convert_hugetlb_size() {
+	local size=$1
+	local units=("KB" "MB" "GB")
+	local idx=0
+
+	while ((size >= 1024)); do
+		((size /= 1024))
+		((idx++))
+	done
+
+	echo "$size${units[$idx]}"
+}
+
+@test "runc run (hugetlb limits)" {
+	requires cgroups_hugetlb
+	[ $EUID -ne 0 ] && requires rootless_cgroup
+	mapfile -t sizes_kb < <(ls /sys/kernel/mm/hugepages/ | sed -e 's/^hugepages-//' -e 's/kB$//')
+	if [ "${#sizes_kb[@]}" -lt 1 ]; then
+		skip "requires hugetlb"
+	fi
+
+	# Create two arrays:
+	#  - sizes: hugetlb cgroup file suffixes;
+	#  - limits: limits for each size.
+	for size in "${sizes_kb[@]}"; do
+		sizes+=("$(convert_hugetlb_size "$size")")
+		# Limit to 1 page.
+		limits+=("$((size*1024))")
+	done
+
+	# Set per-size limits.
+	for ((i = 0; i < ${#sizes[@]}; i++)); do
+		size="${sizes[$i]}"
+		limit="${limits[$i]}"
+		update_config '.linux.resources.hugepageLimits += [{ pagesize: "'"$size"'", limit: '"$limit"' }]'
+	done
+
+	set_cgroups_path
+	runc run -d --console-socket "$CONSOLE_SOCKET" test_hugetlb
+	[ "$status" -eq 0 ]
+
+	lim="max"
+        [ -v CGROUP_V1 ] && lim=".limit_in_bytes"
+
+	optional=("")
+	# Add rsvd, if available.
+	if test -f "$(get_cgroup_path hugetlb)/hugetlb.${sizes[0]}.rsvd.$lim"; then
+		optional+=(".rsvd")
+	fi
+
+	# Check if the limits are as expected.
+	for ((i = 0; i < ${#sizes[@]}; i++)); do
+		size="${sizes[$i]}"
+		limit="${limits[$i]}"
+		for rsvd in "${optional[@]}"; do
+			param="hugetlb.${size}${rsvd}.$lim"
+			echo "checking $param"
+			check_cgroup_value "$param" "$limit"
+		done
+	done
+}
+
 @test "runc run (cgroup v2 resources.unified only)" {
 	requires root cgroups_v2