Expose memory.use_hierarchy in MemoryStats

Signed-off-by: Derek Carr <decarr@redhat.com>

libcontainer/cgroups/fs/memory.go

@@ -243,6 +243,14 @@ func (s *MemoryGroup) GetStats(path string, stats *cgroups.Stats) error {
 	}
 	stats.MemoryStats.KernelTCPUsage = kernelTCPUsage
 
+	useHierarchy := strings.Join([]string{"memory", "use_hierarchy"}, ".")
+	value, err := getCgroupParamUint(path, useHierarchy)
+	if err != nil {
+		return err
+	}
+	if value == 1 {
+		stats.MemoryStats.UseHierarchy = true
+	}
 	return nil
 }
 

libcontainer/cgroups/fs/memory_test.go

@@ -16,6 +16,7 @@ rss 1024`
 	memoryMaxUsageContents     = "4096\n"
 	memoryFailcnt              = "100\n"
 	memoryLimitContents        = "8192\n"
+	memoryUseHierarchyContents = "1\n"
 )
 
 func TestMemorySetMemory(t *testing.T) {
@@ -273,6 +274,7 @@ func TestMemoryStats(t *testing.T) {
 		"memory.kmem.max_usage_in_bytes":  memoryMaxUsageContents,
 		"memory.kmem.failcnt":             memoryFailcnt,
 		"memory.kmem.limit_in_bytes":      memoryLimitContents,
+		"memory.use_hierarchy":            memoryUseHierarchyContents,
 	})
 
 	memory := &MemoryGroup{}
@@ -281,7 +283,7 @@ func TestMemoryStats(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	expectedStats := cgroups.MemoryStats{Cache: 512, Usage: cgroups.MemoryData{Usage: 2048, MaxUsage: 4096, Failcnt: 100, Limit: 8192}, SwapUsage: cgroups.MemoryData{Usage: 2048, MaxUsage: 4096, Failcnt: 100, Limit: 8192}, KernelUsage: cgroups.MemoryData{Usage: 2048, MaxUsage: 4096, Failcnt: 100, Limit: 8192}, Stats: map[string]uint64{"cache": 512, "rss": 1024}}
+	expectedStats := cgroups.MemoryStats{Cache: 512, Usage: cgroups.MemoryData{Usage: 2048, MaxUsage: 4096, Failcnt: 100, Limit: 8192}, SwapUsage: cgroups.MemoryData{Usage: 2048, MaxUsage: 4096, Failcnt: 100, Limit: 8192}, KernelUsage: cgroups.MemoryData{Usage: 2048, MaxUsage: 4096, Failcnt: 100, Limit: 8192}, Stats: map[string]uint64{"cache": 512, "rss": 1024}, UseHierarchy: true}
 	expectMemoryStatEquals(t, expectedStats, actualStats.MemoryStats)
 }
 

libcontainer/cgroups/fs/stats_util_test.go

@@ -84,6 +84,11 @@ func expectMemoryStatEquals(t *testing.T, expected, actual cgroups.MemoryStats)
 	expectMemoryDataEquals(t, expected.SwapUsage, actual.SwapUsage)
 	expectMemoryDataEquals(t, expected.KernelUsage, actual.KernelUsage)
 
+	if expected.UseHierarchy != actual.UseHierarchy {
+		logrus.Printf("Expected memory use hiearchy %v, but found %v\n", expected.UseHierarchy, actual.UseHierarchy)
+		t.Fail()
+	}
+
 	for key, expValue := range expected.Stats {
 		actValue, ok := actual.Stats[key]
 		if !ok {

libcontainer/cgroups/stats.go

@@ -51,6 +51,8 @@ type MemoryStats struct {
 	KernelUsage MemoryData `json:"kernel_usage,omitempty"`
 	// usage of kernel TCP memory
 	KernelTCPUsage MemoryData `json:"kernel_tcp_usage,omitempty"`
+	// if true, memory usage is accounted for throughout a hierarchy of cgroups.
+	UseHierarchy bool `json:"use_hierarchy"`
 
 	Stats map[string]uint64 `json:"stats,omitempty"`
 }