1704534 - Add a method for mozilla::Task to know if it can be executed next.

Status: RESOLVED WONTFIX

(Core :: XPCOM, enhancement, P3)

Description

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi] OOO ~ Feb.7]

For the off-thread tasks in Spidermonkey, most of them have a limit for maximum parallel executions.
https://searchfox.org/mozilla-central/rev/fa48ebee58d59fa846919c3e2c3122b08db57c9c/js/src/vm/HelperThreads.cpp#1510

When dispatching these tasks to TaskController, it would be quite helpful if TaskController can check the method added in mozilla::Task before executing it.
https://searchfox.org/mozilla-central/rev/fa48ebee58d59fa846919c3e2c3122b08db57c9c/xpcom/threads/TaskController.cpp#245

Comment 1

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi] OOO ~ Feb.7]

Attachment: Bug 1704534 : Add CanBeExecuted() method for mozilla::Task.

Comment 2

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi] OOO ~ Feb.7]

Found out I could return false in Task::Run to tell TaskController to re-run this task again.
https://searchfox.org/mozilla-central/rev/b6f52976b562008c9d9ceeda22907e1eda506c8e/xpcom/threads/TaskController.h#194

Comment 3

[Yoshi Cheng-Hao Huang [:allstars.chh][:allstarschh][:yoshi] OOO ~ Feb.7]

see https://bugzilla.mozilla.org/show_bug.cgi?id=1706357#c7

Comment 4

[Jon Coppeard (:jonco)]

The current plan doesn't require this. We will only dispatch a task to the thread pool if there is a task that can run under the current system of limits.