1126169 - Allow system app to run out-of-process

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: Gaia::System, defect)

Description

[Kan-Ru Chen [:kanru] (UTC+9)]

Currently system-app resides in the chrome/b2g process. System UI often occupies the chrome process main thread, a scarce resource. Run system-app out-of-process would reduce the chance that content processes are blocked by the chrome process.

Comment 1

[[:fabrice] Fabrice Desré]

Kan-Ru, is the goal to move the full system app OOP here? or only the UI parts? We'd really like to experiment with the later at least.
Remember also that we moved some pieces back in process for performance reasons...

Comment 2

[Kan-Ru Chen [:kanru] (UTC+9)]

(In reply to Fabrice Desré [:fabrice] from comment #1)
> Kan-Ru, is the goal to move the full system app OOP here? or only the UI
> parts? We'd really like to experiment with the later at least.
> Remember also that we moved some pieces back in process for performance
> reasons...

The goal of this bug is to move the full system app OOP. However only moving the UI parts seemed more likely to success in a short time as it doesn't depend on the nested-oop feature. So I agree we should at least try to move the UI part OOP.

Comment 3

[Kan-Ru Chen [:kanru] (UTC+9)]

We discussed this offline and fabrice said we could replace mozChromeEvent with a certified-only API so it works OOP. Pondered a while, I think we could send/listen mozChromeEvent/mozContentEvent from a frame script so we probably don't need a new API for this.

Comment 4

[Kan-Ru Chen [:kanru] (UTC+9)]

Attachment: WIP patch

Had to escape some security check and seccomp sandbox, but I could open and profile the Gallery app.

% b2g-ps
APPLICATION    SEC USER     PID   PPID  VSIZE  RSS     WCHAN    PC         NAME
b2g              0 root      8149  1     164040 58944 ffffffff b6e7e894 S /system/b2g/b2g
(Nuwa)           0 root      8155  8149  64644  21884 ffffffff b6e7e894 S /system/b2g/b2g
System           0 u0_a8258  8258  8149  138500 65264 ffffffff b6ec1894 S /system/b2g/plugin-container
Homescreen       0 u0_a8272  8272  8155  114928 32888 ffffffff b6e7e894 S /system/b2g/b2g
Built-in Keyboa  0 u0_a8411  8411  8149  89440  31624 ffffffff b6f06894 S /system/b2g/plugin-container
Usage            0 u0_a8413  8413  8155  72076  24584 ffffffff b6e7e894 S /system/b2g/b2g
(Preallocated a  0 u0_a8685  8685  8155  68924  16728 ffffffff b6e7e894 S /system/b2g/b2g

https://people.mozilla.org/~bgirard/cleopatra/#report=372aa8a3f856ab460d729bbc8076166006217dc2

Comment 5

[Kan-Ru Chen [:kanru] (UTC+9)]

After minimizing an app, the system app crashes at
http://mxr.mozilla.org/mozilla-central/source/dom/ipc/Blob.cpp#140
probably during saving a screenshot.

Comment 6

[BMO Automation]

Firefox OS is not being worked on