com.webos.service.memorymanager

Note
This API has been available since API level 11.

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

getManagerEvent

ACG: memorymanager.query

Deprecated

Added: API level 11
Deprecated: API level 15

Description

Subscribe to be notified when a MemoryManager internal event occurs.

Parameters

Name	Required	Type	Description
type	Required	String	Indicates the memory manager event type. Possible values are: killing: application killing event when memory level is under 'low'
subscribe	Required	Boolean	Indicates if subscribed for notifications. Possible values are: true: Subscribe for notifications false: Notifications are not required

Name

Required

Type

Description

type

Required

String

Indicates the memory manager event type.

Possible values are:

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

Required

Boolean

Indicates if subscribed for notifications.

Possible values are:

true: Subscribe for notifications
false: Notifications are not required

Call Returns

Name	Required	Type	Description
subscribed	Required	Boolean	Indicates if subscribed to get notifications. true: Subscribed for notifications false: Not subscribed
returnValue	Required	Boolean	Indicates the status of the operation. Possible values are: true: Method execution is successful false: Method executed with errors. Check the errorCode and errorText 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	Indicates the app ID. Note: 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 the operation. Possible values are: true: Method execution is successful false: Method executed with errors. Check the errorCode and errorText for details.
subscribed	Required	Boolean	Indicates if subscribed to get notifications. true: Subscribed for notifications false: Not subscribed
instanceId	Optional	String	Indicates the instance ID.

Example

Example code

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

Response:

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

Subscription response:

{
"subscribed": true,
"returnValue": true,
"instanceId": "339164a1-2d8d-4d93-819b-427b5c12a75b1",
"id": "com.webos.app.test.enact",
"type": "killing"
}

getMemoryStatus

ACG: memorymanager.query

Added: API level 11

Description

Provides the 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: false

Name

Required

Type

Description

Optional

Boolean

Subscribe for notifications.

Possible values are:

true: Get notifications
false: Notifications are not required

Default: false

Call Returns

Name	Required	Type	Description
applications	Required	Object array: application	Indicates the list of running applications.
system	Required	Object: system	Indicates the current system information.
threshold	Required	Object: threshold	Indicates the threshold values.
subscribed	Required	Boolean	Subscribe for notifications. Possible values are: true: Get notifications false: Notifications are not required
returnValue	Required	Boolean	Indicates the status of the operation. Possible values are: true: Method execution is successful false: Method executed with errors. Check the errorCode and errorText 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

Example code

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

Response:

{
"subscribed": true,
"returnValue": true,
"system": {
"level": "normal",
"available": 5995,
"total": 7538
},
"threshold": {
"low": {
"enter": 250,
"exit": 280
},
"critical": {
"enter": 100,
"exit": 130
}
},
"applications": [
{
"appId": "com.webos.app.test.enact",
"instanceId": "56a536ae-bf17-45f3-a255-4ba521b9081e1",
"pid": 2499,
"status": "foreground",
"type": "web",
"pss": "0"
}
]
}

requireMemory

ACG: memorymanager.management

Added: API level 11

Description

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

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

Parameters

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

Call Returns

Name	Required	Type	Description
returnValue	Required	Boolean	Indicates the status of the operation. This method always returns true.
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 the operation.

This method always returns true.

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

Example code

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

Response:

{
"returnValue":true
}

sysInfo

ACG: memorymanager.query

Retired

Added: API level 13
Deprecated: API level 15
Retired: API level 25

Description

Provides a way to account for memory usage.

Parameters

None

Call Returns

Name	Required	Type	Description
returnValue	Required	Boolean	Indicates the status of the operation. Possible values are: true: Method execution is successful false: Method executed with errors. Check the errorCode and errorText 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.
System View	Required	Object array: system_view	Indicates the system level memory information.
PSS View	Required	Object array: pss_view	Indicates the PSS information of services and applications per session.

Example

Example code

# luna-send -f -n 1 luna://com.webos.service.memorymanager/sysInfo '{ }'

Response:

{
"returnValue":true,
"System View":[
{
"Essential":[
"BSP : 669224 K",
"Custom Kernel : 513466 K",
"Kernel : 508892 K",
"System PSS : 750928 K"
]
},
{
"Foreground":[
"Foreground PSS : 90490 K"
]
},
{
"Performance":[
"Cached Kernel : 304672 K",
"Cached PSS : 0 K"
]
},
{
"Free":[
"Free : 5550936 K"
]
}
],
"PSS View":[
{
"driver0":[
{
"System":[
"55096 K: maliit-server.service (pid 2016)",
"39725 K: webapp-mgr.service (pid 1631)",
"...",
"297 K: maliit-server.service (pid 1995)"
]
},
{
"Foreground":[
"30414 K: com.webos.app.firstuse (pid 1835)"
]
}
]
},
{
"guest0":[
{
"System":[
"54682 K: maliit-server.service (pid 1987)",
"45024 K: webapp-mgr.service (pid 1514)",
"...",
"291 K: maliit-server.service (pid 1957)"
]
},
{
"Foreground":[
"30119 K: com.webos.app.firstuse (pid 1837)"
]
}
]
},
{
"guest1":[
{
"System":[
"54676 K: maliit-server.service (pid 2064)",
"42434 K: webapp-mgr.service (pid 1556)",
"...",
"285 K: maliit-server.service (pid 2030)"
]
},
{
"Foreground":[
"29957 K: com.webos.app.firstuse (pid 1834)"
]
}
]
},
{
"host":[
{
"System":[
"43910 K: surface-manager-daemon.service (pid 1010)",
"5957 K: pulseaudio.service (pid 1040)",
"...",
"163 K: qrtr-ns.service (pid 477)"
]
}
]
}
]
}

Objects

application

Indicates the application memory description.

Name	Required	Type	Description
appId	Required	String	Indicates the application ID.
status	Required	String	Indicates the status of the application. Possible values are: foreground background unknown ....
pid	Required	Number	Indicates the process ID.
time	Required	Number	Indicates the timestamp about 'foreground' apps.
type	Required	String	Indicates the application type. Possible values are: web native qml unknown

pss_view

PSS information of services and applications per session

Name	Required	Type	Description
host	Required	Object array	Indicates the PSS information on host session.
driver0	Optional	Object array	Indicates the PSS information on driver0 session.
guest0	Optional	Object array	Indicates the PSS information on guest0 session.
guest1	Optional	Object array	Indicates the PSS information on guest1 session.

system

Indicates the current memory information.

Name	Required	Type	Description
available	Required	Number	Indicates the available memory.
total	Required	Number	Indicates the total memory.
level	Required	String	Indicates the current memory status. Possible values are: normal low critical

Name

Required

Type

Description

available

Required

Number

Indicates the available memory.

total

Required

Number

Indicates the total memory.

level

Required

String

Indicates the current memory status.

Possible values are:

normal
low
critical

system_view

Provides system-level memory information.

Name	Required	Type	Description
Essential	Required	String array	Indicates the essential memory to run the system. Values are: BSP Kernel Custom Kernel System PSS
Foreground	Required	String array	Indicates the memory of processes that interacts with users. Value is: Foreground PSS
Free	Required	String array	Indicates the free memory. Value is: Free
Performance	Required	String array	Indicates the memory that does not interact with users, but memory for performance improvement. Values are: Cached Kernel Cached PSS

threshold

Indicates the memory level threshold.

Name	Required	Type	Description
low	Required	Object: threshold_item	Indicates the low threshold.
critical	Required	Object: threshold_item	Indicates the critical threshold.

threshold_item

Indicates the threshold item.

Name	Required	Type	Description
enter	Required	Number	Indicates the enter threshold.
exit	Required	Number	Indicates the exit threshold.

Signals/Events

levelChanged

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

Call Returns

Name	Required	Type	Description
previous	Required	String	Indicates the previous memory level.
current	Required	String	Indicates the 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