Stop relying on number of subsystems for cgroups

When there are complicated mount setups, there can be multiple mount points which have the subsystem we are looking for. Instead of counting the mountpoints, tick off subsystems until we have found them all. Without the 'all' flag, ignore duplicate subsystems after the first. Signed-off-by: Daniel Dao <dqminh89@gmail.com>
dims · Jun 23, 2018 · 34b443e · 34b443e
1 parent a85a674
commit 34b443e
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Showing 2 changed files with 47 additions and 48 deletions.
diff --git a/libcontainer/cgroups/utils.go b/libcontainer/cgroups/utils.go
@@ -151,17 +151,16 @@ func getCgroupMountsHelper(ss map[string]bool, mi io.Reader, all bool) ([]Mount,
 			Root:       fields[3],
 		}
 		for _, opt := range strings.Split(fields[len(fields)-1], ",") {
-			if !ss[opt] {
+			seen, known := ss[opt]
+			if !known || (!all && seen) {
 				continue
 			}
 			if strings.HasPrefix(opt, cgroupNamePrefix) {
-				m.Subsystems = append(m.Subsystems, opt[len(cgroupNamePrefix):])
-			} else {
-				m.Subsystems = append(m.Subsystems, opt)
-			}
-			if !all {
-				numFound++
+				opt = opt[len(cgroupNamePrefix):]
 			}
+			m.Subsystems = append(m.Subsystems, opt)
+			ss[opt] = true
+			numFound++
 		}
 		res = append(res, m)
 	}
@@ -187,7 +186,7 @@ func GetCgroupMounts(all bool) ([]Mount, error) {
 
 	allMap := make(map[string]bool)
 	for s := range allSubsystems {
-		allMap[s] = true
+		allMap[s] = false
 	}
 	return getCgroupMountsHelper(allMap, f, all)
 }

diff --git a/libcontainer/cgroups/utils_test.go b/libcontainer/cgroups/utils_test.go
@@ -132,31 +132,31 @@ func TestGetCgroupMounts(t *testing.T) {
 			mountInfo: fedoraMountinfo,
 			root:      "/",
 			subsystems: map[string]bool{
-				"cpuset":     true,
-				"cpu":        true,
-				"cpuacct":    true,
-				"memory":     true,
-				"devices":    true,
-				"freezer":    true,
-				"net_cls":    true,
-				"blkio":      true,
-				"perf_event": true,
-				"hugetlb":    true,
+				"cpuset":     false,
+				"cpu":        false,
+				"cpuacct":    false,
+				"memory":     false,
+				"devices":    false,
+				"freezer":    false,
+				"net_cls":    false,
+				"blkio":      false,
+				"perf_event": false,
+				"hugetlb":    false,
 			},
 		},
 		{
 			mountInfo: systemdMountinfo,
 			root:      "/system.slice/docker-dc4eaa1a34ec4d593bc0125d31eea823a1d76ae483aeb1409cca80304e34da2e.scope",
 			subsystems: map[string]bool{
-				"cpuset":     true,
-				"cpu":        true,
-				"cpuacct":    true,
-				"memory":     true,
-				"devices":    true,
-				"freezer":    true,
-				"net_cls":    true,
-				"blkio":      true,
-				"perf_event": true,
+				"cpuset":     false,
+				"cpu":        false,
+				"cpuacct":    false,
+				"memory":     false,
+				"devices":    false,
+				"freezer":    false,
+				"net_cls":    false,
+				"blkio":      false,
+				"perf_event": false,
 			},
 		},
 	}
@@ -199,16 +199,16 @@ func TestGetCgroupMounts(t *testing.T) {
 
 func BenchmarkGetCgroupMounts(b *testing.B) {
 	subsystems := map[string]bool{
-		"cpuset":     true,
-		"cpu":        true,
-		"cpuacct":    true,
-		"memory":     true,
-		"devices":    true,
-		"freezer":    true,
-		"net_cls":    true,
-		"blkio":      true,
-		"perf_event": true,
-		"hugetlb":    true,
+		"cpuset":     false,
+		"cpu":        false,
+		"cpuacct":    false,
+		"memory":     false,
+		"devices":    false,
+		"freezer":    false,
+		"net_cls":    false,
+		"blkio":      false,
+		"perf_event": false,
+		"hugetlb":    false,
 	}
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
@@ -276,17 +276,17 @@ func TestParseCgroupString(t *testing.T) {
 
 func TestIgnoreCgroup2Mount(t *testing.T) {
 	subsystems := map[string]bool{
-		"cpuset":       true,
-		"cpu":          true,
-		"cpuacct":      true,
-		"memory":       true,
-		"devices":      true,
-		"freezer":      true,
-		"net_cls":      true,
-		"blkio":        true,
-		"perf_event":   true,
-		"pids":         true,
-		"name=systemd": true,
+		"cpuset":       false,
+		"cpu":          false,
+		"cpuacct":      false,
+		"memory":       false,
+		"devices":      false,
+		"freezer":      false,
+		"net_cls":      false,
+		"blkio":        false,
+		"perf_event":   false,
+		"pids":         false,
+		"name=systemd": false,
 	}
 
 	mi := bytes.NewBufferString(cgroup2Mountinfo)