com.webos.service.memorymanager

API Summary

Manages applications to ensure that the system does not run into kernel-Out-Of-Memory situation. This is achieved by killing applications that are in the background when we reach low memory conditions.

The goal of MemoryManager:

To maintain the state of memory usage across the app
To prevent running OOM (out of memory)
To correct the situation where memory runs out.

Overview of the API

N/A

Methods

getMemoryStatus

Description

Provides current status of the memory.

Parameters

Name	Required	Type	Description
subscribe	Optional	Boolean	Subscribe for notifications. Possible values are: true - Get notifications false - Notifications are not required Default value: false

Name

Required

Type

Description

Optional

Boolean

Subscribe for notifications. Possible values are:

true - Get notifications
false - Notifications are not required

Default value: false

Call Returns

Name	Required	Type	Description
applications	Required	Object array: application	List of running applications.
system	Required	Object: system	Current system information.
threshold	Required	Object: threshold	Threshold values.
subscribed	Required	Boolean	Indicates if subscribed to get notified. true - Subscribed for changes false - Not subscribed
returnValue	Required	Boolean	Indicates the status of operation. Possible values are: true - Indicates that the operation was successful. false - Indicates that the operation failed. Check "errorText" field for details.
errorCode	Optional	Number	The error code for the failed operation.
errorText	Optional	String	Indicates the reason for the failure of the operation. See the "API Error Codes Reference" section for details.

Example

root@raspberrypi3:~# luna-send -f -i luna://com.webos.service.memorymanager/getMemoryStatus '{ "subscribe":true }'

Returns:
{
    "applications": [
        {
            "appId": "com.webos.app.test.enact",
            "status": "foreground",
            "pid": 2528,
            "time": 11147,
            "type": "web"
        }
    ],
    "system": {
        "free": 386,
        "total": 681,
        "level": "normal"
    },
    "threshold": {
        "low": {
         "enter": 200,
         "exit": 250
        },
        "critical": {
         "enter": 100,
         "exit": 150
        }
    },
    "returnValue": true,
    "subscribed": true
}

getManagerEvent

Description

Subscribe to be notified when a MemoryManager internal event occurs.

Parameters

Name	Required	Type	Description
type	Required	String	Memory Manager Event Type. 'killing' : application killing event when memory level is under 'low'
subscribe	Required	Boolean	Subscribe for notifications. Possible values are: true - Get notifications false - Notifications are not required This is subscription API so value MUST true.

Name

Required

Type

Description

type

Required

String

Memory Manager Event Type.

'killing' : application killing event when memory level is under 'low'

Required

Boolean

Subscribe for notifications. Possible values are:

true - Get notifications
false - Notifications are not required

This is subscription API so value MUST true.

Call Returns

Name	Required	Type	Description
subscribed	Required	Boolean	Indicates if subscribed to get notified. true - Subscribed for changes false - Not subscribed
returnValue	Required	Boolean	Indicates the status of operation. Possible values are: true - Indicates that the operation was successful. false - Indicates that the operation failed. Check "errorText" field for details.
errorCode	Optional	Number	The error code for the failed operation.
errorText	Optional	String	Indicates the reason for the failure of the operation. See the "API Error Codes Reference" section for details.

Subscription Returns

Name	Required	Type	Description
id	Optional	String	The app ID. The value exists only for 'killing' type event.
type	Required	String	Memory Manager Event Type. 'killing' : application killing event when memory level is under 'low'
returnValue	Required	Boolean	Indicates the status of operation. Possible values are: true - Indicates that the operation was successful. false - Indicates that the operation failed. Check "errorText" field for details.
subscribed	Required	Boolean	Indicates if subscribed to get notified. true - Subscribed for changes false - Not subscribed

Example

root@raspberrypi3:~# luna-send -f -i luna://com.webos.service.memorymanager/getManagerEvent '{ "type": "killing", "subscribe":true }'

Returns:
{
"subscribed": true,
"returnValue": true
}

Subscription returns:
{
"id": "com.webos.app.test.enact",
"type": "killing",
"subscribed": true,
"returnValue": true
}

requireMemory

Description

Requests for the memory that is required to launch an application.

Note: This method is called by SAM when it about to launch an application.

Parameters

Name	Required	Type	Description
requiredMemory	Required	Number	Amount of memory required to launch the application.

Call Returns

Name	Required	Type	Description
returnValue	Required	Boolean	Indicates the status of operation. Possible values are: true - Indicates that the operation was successful. false - Indicates that the operation failed. Check "errorText" field for details.
errorCode	Optional	Number	The error code for the failed operation.
errorText	Optional	String	Indicates the reason for the failure of the operation. See the "API Error Codes Reference" section for details.

Name

Required

Type

Description

returnValue

Required

Boolean

Indicates the status of operation. Possible values are:

true - Indicates that the operation was successful.
false - Indicates that the operation failed. Check "errorText" field for details.

errorCode

Optional

Number

The error code for the failed operation.

errorText

Optional

String

Indicates the reason for the failure of the operation. See the "API Error Codes Reference" section for details.

Example

root@raspberrypi3:~# luna-send -f -n 1 luna://com.webos.service.memorymanager/requireMemory '{ "requiredMemory": 120 }'

Returns:
{
"returnValue": true
}

Objects

system

Current memory information

Name	Required	Type	Description
free	Required	Number	Free memory.
total	Required	Number	Total memory.
level	Required	String	Current memory status. Possible values are: normal low critical

Name

Required

Type

Description

free

Required

Number

Free memory.

total

Required

Number

Total memory.

level

Required

String

Current memory status. Possible values are:

normal
low
critical

application

application memory description.

Name	Required	Type	Description
appId	Required	String	Application ID.
status	Required	String	Status of application. Possible values are: foreground background unknown ....
pid	Required	Number	Process ID.
time	Required	Number	Timestamp about 'foreground' apps.
type	Required	String	Application type. Possible values are: web native qml unknown

threshold

memory level threshold

Name	Required	Type	Description
low	Required	Object: threshold_item	Low threshold.
critical	Required	Object: threshold_item	Critical threshold.

threshold_item

Threshold Item.

Name	Required	Type	Description
enter	Required	Number	Enter threshold.
exit	Required	Number	Exit threshold.

Signals/Events

levelChanged

LS signal for memory level change. The signal is always sent whenever memory level is changed.

Call Returns

Name	Required	Type	Description
previous	Required	Number	Previous memory level.
current	Required	Number	Current memory level.

API Error Codes Reference

Error Code	Error Text	Error Description
1	Unknown Error	Unknown Error
2	Wrong Json Format Error	Wrong Json Format Error
3	No Required Parameters Error	No Required Parameters Error
4	Invalid Parameters Error	Invalid Parameters Error
5	LS2 Internal Error	LS2 Internal Error
6	Unsupported API	Unsupported API