@@ -21,7 +21,7 @@ func (daemon *Daemon) ContainerCreate(params types.ContainerCreateConfig) (types

 		return types.ContainerCreateResponse{}, derr.ErrorCodeEmptyConfig

 	}

-	warnings, err := daemon.verifyContainerSettings(params.HostConfig, params.Config)

+	warnings, err := daemon.verifyContainerSettings(params.HostConfig, params.Config, false)

 	if err != nil {

 		return types.ContainerCreateResponse{Warnings: warnings}, err

 	}

@@ -1450,7 +1450,7 @@ func setDefaultMtu(config *Config) {

 // verifyContainerSettings performs validation of the hostconfig and config

 // structures.

-func (daemon *Daemon) verifyContainerSettings(hostConfig *containertypes.HostConfig, config *containertypes.Config) ([]string, error) {

+func (daemon *Daemon) verifyContainerSettings(hostConfig *containertypes.HostConfig, config *containertypes.Config, update bool) ([]string, error) {

 	// First perform verification of settings common across all platforms.

 	if config != nil {

@@ -1487,7 +1487,7 @@ func (daemon *Daemon) verifyContainerSettings(hostConfig *containertypes.HostCon

 	}

 	// Now do platform-specific verification

-	return verifyPlatformContainerSettings(daemon, hostConfig, config)

+	return verifyPlatformContainerSettings(daemon, hostConfig, config, update)

 }

 // Checks if the client set configurations for more than one network while creating a container

@@ -221,7 +221,7 @@ func (daemon *Daemon) adaptContainerSettings(hostConfig *containertypes.HostConf

 	return nil

 }

-func verifyContainerResources(resources *containertypes.Resources, sysInfo *sysinfo.SysInfo) ([]string, error) {

+func verifyContainerResources(resources *containertypes.Resources, sysInfo *sysinfo.SysInfo, update bool) ([]string, error) {

 	warnings := []string{}

 	// memory subsystem checks and adjustments

@@ -242,7 +242,7 @@ func verifyContainerResources(resources *containertypes.Resources, sysInfo *sysi

 	if resources.Memory > 0 && resources.MemorySwap > 0 && resources.MemorySwap < resources.Memory {

 		return warnings, fmt.Errorf("Minimum memoryswap limit should be larger than memory limit, see usage.")

 	}

-	if resources.Memory == 0 && resources.MemorySwap > 0 {

+	if resources.Memory == 0 && resources.MemorySwap > 0 && !update {

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

 	}

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

@@ -383,7 +383,7 @@ func (daemon *Daemon) usingSystemd() bool {

 // verifyPlatformContainerSettings performs platform-specific validation of the

 // hostconfig and config structures.

-func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *containertypes.HostConfig, config *containertypes.Config) ([]string, error) {

+func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *containertypes.HostConfig, config *containertypes.Config, update bool) ([]string, error) {

 	warnings := []string{}

 	sysInfo := sysinfo.New(true)

@@ -392,7 +392,7 @@ func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *containertypes.

 		return warnings, err

 	}

-	w, err := verifyContainerResources(&hostConfig.Resources, sysInfo)

+	w, err := verifyContainerResources(&hostConfig.Resources, sysInfo, update)

 	if err != nil {

 		return warnings, err

 	}

@@ -85,7 +85,7 @@ func (daemon *Daemon) adaptContainerSettings(hostConfig *containertypes.HostConf

 // verifyPlatformContainerSettings performs platform-specific validation of the

 // hostconfig and config structures.

-func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *containertypes.HostConfig, config *containertypes.Config) ([]string, error) {

+func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *containertypes.HostConfig, config *containertypes.Config, update bool) ([]string, error) {

 	return nil, nil

 }

@@ -58,7 +58,7 @@ func (daemon *Daemon) ContainerStart(name string, hostConfig *containertypes.Hos

 	// 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 {

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

 		return err

 	}

 	// Adapt for old containers in case we have updates in this function and

@@ -12,7 +12,7 @@ import (

 func (daemon *Daemon) ContainerUpdate(name string, hostConfig *container.HostConfig) ([]string, error) {

 	var warnings []string

-	warnings, err := daemon.verifyContainerSettings(hostConfig, nil)

+	warnings, err := daemon.verifyContainerSettings(hostConfig, nil, true)

 	if err != nil {

 		return warnings, err

 	}

@@ -139,6 +139,22 @@ func (s *DockerSuite) TestUpdateKernelMemory(c *check.C) {

 	c.Assert(strings.TrimSpace(out), checker.Equals, "104857600")

 }

+func (s *DockerSuite) TestUpdateSwapMemoryOnly(c *check.C) {

+	testRequires(c, DaemonIsLinux)

+	testRequires(c, memoryLimitSupport)

+	testRequires(c, swapMemorySupport)

+

+	name := "test-update-container"

+	dockerCmd(c, "run", "-d", "--name", name, "--memory", "300M", "--memory-swap", "500M", "busybox", "top")

+	dockerCmd(c, "update", "--memory-swap", "600M", name)

+

+	c.Assert(inspectField(c, name, "HostConfig.MemorySwap"), checker.Equals, "629145600")

+

+	file := "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes"

+	out, _ := dockerCmd(c, "exec", name, "cat", file)

+	c.Assert(strings.TrimSpace(out), checker.Equals, "629145600")

+}

+

 func (s *DockerSuite) TestUpdateStats(c *check.C) {

 	testRequires(c, DaemonIsLinux)

 	testRequires(c, memoryLimitSupport)