@@ -155,6 +155,8 @@ func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *runconfig.HostC

 	if hostConfig.LxcConf.Len() > 0 && !strings.Contains(daemon.ExecutionDriver().Name(), "lxc") {

 		return warnings, fmt.Errorf("Cannot use --lxc-conf with execdriver: %s", daemon.ExecutionDriver().Name())

 	}

+

+	// memory subsystem checks and adjustments

 	if hostConfig.Memory != 0 && hostConfig.Memory < 4194304 {

 		return warnings, fmt.Errorf("Minimum memory limit allowed is 4MB")

 	}

@@ -162,6 +164,7 @@ func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *runconfig.HostC

 		warnings = append(warnings, "Your kernel does not support memory limit capabilities. Limitation discarded.")

 		logrus.Warnf("Your kernel does not support memory limit capabilities. Limitation discarded.")

 		hostConfig.Memory = 0

+		hostConfig.MemorySwap = -1

 	}

 	if hostConfig.Memory > 0 && hostConfig.MemorySwap != -1 && !sysInfo.SwapLimit {

 		warnings = append(warnings, "Your kernel does not support swap limit capabilities, memory limited without swap.")

@@ -174,7 +177,7 @@ func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *runconfig.HostC

 	if hostConfig.Memory == 0 && hostConfig.MemorySwap > 0 {

 		return warnings, fmt.Errorf("You should always set the Memory limit when using Memoryswap limit, see usage.")

 	}

-	if hostConfig.MemorySwappiness != nil && !sysInfo.MemorySwappiness {

+	if hostConfig.MemorySwappiness != nil && *hostConfig.MemorySwappiness != -1 && !sysInfo.MemorySwappiness {

 		warnings = append(warnings, "Your kernel does not support memory swappiness capabilities, memory swappiness discarded.")

 		logrus.Warnf("Your kernel does not support memory swappiness capabilities, memory swappiness discarded.")

 		hostConfig.MemorySwappiness = nil

@@ -214,10 +217,12 @@ func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *runconfig.HostC

 	if hostConfig.BlkioWeight > 0 && (hostConfig.BlkioWeight < 10 || hostConfig.BlkioWeight > 1000) {

 		return warnings, fmt.Errorf("Range of blkio weight is from 10 to 1000.")

 	}

+

 	if hostConfig.OomKillDisable && !sysInfo.OomKillDisable {

 		hostConfig.OomKillDisable = false

 		return warnings, fmt.Errorf("Your kernel does not support oom kill disable.")

 	}

+

 	if sysInfo.IPv4ForwardingDisabled {

 		warnings = append(warnings, "IPv4 forwarding is disabled. Networking will not work.")

 		logrus.Warnf("IPv4 forwarding is disabled. Networking will not work")

@@ -21,10 +21,6 @@ func (daemon *Daemon) ContainerStart(name string, hostConfig *runconfig.HostConf

 		return fmt.Errorf("Container already started")

 	}

-	if _, err = daemon.verifyContainerSettings(hostConfig, nil); err != nil {

-		return err

-	}

-

 	// Windows does not have the backwards compatibilty issue here.

 	if runtime.GOOS != "windows" {

 		// This is kept for backward compatibility - hostconfig should be passed when

@@ -40,6 +36,12 @@ func (daemon *Daemon) ContainerStart(name string, hostConfig *runconfig.HostConf

 		}

 	}

+	// check if hostConfig is in line with the current system settings.

+	// It may happen cgroups are umounted or the like.

+	if _, err = daemon.verifyContainerSettings(container.hostConfig, nil); err != nil {

+		return err

+	}

+

 	if err := container.Start(); err != nil {

 		return fmt.Errorf("Cannot start container %s: %s", name, err)

 	}

@@ -188,16 +188,16 @@ func Parse(cmd *flag.FlagSet, args []string) (*Config, *HostConfig, *flag.FlagSe

 		flMemory = parsedMemory

 	}

-	var MemorySwap int64

+	var memorySwap int64

 	if *flMemorySwap != "" {

 		if *flMemorySwap == "-1" {

-			MemorySwap = -1

+			memorySwap = -1

 		} else {

 			parsedMemorySwap, err := units.RAMInBytes(*flMemorySwap)

 			if err != nil {

 				return nil, nil, cmd, err

 			}

-			MemorySwap = parsedMemorySwap

+			memorySwap = parsedMemorySwap

 		}

 	}

@@ -354,7 +354,7 @@ func Parse(cmd *flag.FlagSet, args []string) (*Config, *HostConfig, *flag.FlagSe

 		ContainerIDFile:  *flContainerIDFile,

 		LxcConf:          lxcConf,

 		Memory:           flMemory,

-		MemorySwap:       MemorySwap,

+		MemorySwap:       memorySwap,

 		CPUShares:        *flCPUShares,

 		CPUPeriod:        *flCPUPeriod,

 		CpusetCpus:       *flCpusetCpus,