Fix MaxCPU and MaxMemory semantics

If a limit of 0 (or negative) is given for both cpu and memory, then
no limiting will be triggered. If any value between 1 and 100 (inclusive)
is given, then limiting will be triggered when that limit is reached.

I.e. giving a limit of 100 doesn't not mean unlimited.

resources/resources.go

@@ -54,6 +54,12 @@ type Config struct {
 }
 
 func New(config Config) (Resources, error) {
+	isUnlimited := false
+
+	if config.MaxCPU <= 0 && config.MaxMemory <= 0 {
+		isUnlimited = true
+	}
+
 	if config.MaxCPU <= 0 {
 		config.MaxCPU = 100
 	}
@@ -69,13 +75,10 @@ func New(config Config) (Resources, error) {
 	r := &resources{
 		maxCPU:      config.MaxCPU,
 		psutil:      config.PSUtil,
+		isUnlimited: isUnlimited,
 		logger:      config.Logger,
 	}
 
-	if config.MaxCPU == 100 && config.MaxMemory == 100 {
-		r.isUnlimited = true
-	}
-
 	if r.logger == nil {
 		r.logger = log.New("")
 	}
@@ -167,33 +170,37 @@ func (r *resources) observe(ctx context.Context, interval time.Duration) {
 
 			doCPULimit := false
 
+			if !r.isUnlimited {
 				if !r.isCPULimiting {
-				if cpuload > r.maxCPU {
+					if cpuload >= r.maxCPU {
 						r.logger.Debug().WithField("cpu", cpuload).Log("CPU limit reached")
 						doCPULimit = true
 					}
 				} else {
 					doCPULimit = true
-				if cpuload <= r.maxCPU {
+					if cpuload < r.maxCPU {
 						r.logger.Debug().WithField("cpu", cpuload).Log("CPU limit released")
 						doCPULimit = false
 					}
 				}
+			}
 
 			doMemoryLimit := false
 
+			if !r.isUnlimited {
 				if !r.isMemoryLimiting {
-				if vmstat.Used > r.maxMemory {
+					if vmstat.Used >= r.maxMemory {
 						r.logger.Debug().WithField("memory", vmstat.Used).Log("Memory limit reached")
 						doMemoryLimit = true
 					}
 				} else {
 					doMemoryLimit = true
-				if vmstat.Used <= r.maxMemory {
+					if vmstat.Used < r.maxMemory {
 						r.logger.Debug().WithField("memory", vmstat.Used).Log("Memory limit released")
 						doMemoryLimit = false
 					}
 				}
+			}
 
 			r.lock.Lock()
 			if r.isCPULimiting != doCPULimit {

resources/resources_test.go

@@ -177,6 +177,16 @@ func TestHasLimits(t *testing.T) {
 
 	require.True(t, r.HasLimits())
 
+	r, err = New(Config{
+		MaxCPU:    100,
+		MaxMemory: 100,
+		PSUtil:    &util{},
+		Logger:    nil,
+	})
+	require.NoError(t, err)
+
+	require.True(t, r.HasLimits())
+
 	r, err = New(Config{
 		MaxCPU:    0,
 		MaxMemory: 0,