Major refactoring of Scheduler/Task #339

rdaum · 2024-06-26T21:07:42Z

**Sorry this one is going to be hard to read as any kind of diff. If you're worried, I recommend just reading the whole of scheduler.rs and task.rs. **

Highlights:

Suspended tasks no longer hog a thread and idle. Instead their thread ends and they are moved into a suspended vector inside the scheduler itself.
Tasks that start in a delayed state (e.g. forks) now no longer use a thread with a manual delay. Instead they begin their life in suspended state and are picked up by the scheduler tick.
Gut the remainder of the complicated dispatch logic that was leftover from the old async/tokio version of this code. Intermediate result objects (which used to be processed in batch) are gone, and actions are immediately acted on. This should be a lot easier to read now.

I believe this paves the way for a more testable, robust future.

Highlights: * Suspended tasks no longer hog a thread and idle. Instead their thread ends and they are moved into a suspended vector inside the scheduler itself. * Tasks that start in a delayed state (e.g. forks) now no longer use a thread with a manual delay. Instead they begin their life in suspended state and are picked up by the scheduler tick. * Gut the remainder of the complicated dispatch logic that was leftover from the old async/tokio version of this code. Intermediate result objects (which used to be processed in batch) are gone, and actions are immediately acted on. This should be a lot easier to read now. I believe this paves the way for a more testable, robust future.

* Run simple program to completion * Throw an exception * `suspend()` and resume * `read()`` and resume * fork

crates/kernel/src/builtins/bf_server.rs

crates/kernel/src/tasks/scheduler.rs

crates/kernel/src/tasks/task.rs

crates/kernel/src/tasks/vm_host.rs

crates/kernel/src/tasks/task.rs

rdaum requested review from abesto and nnunley June 26, 2024 21:08

rdaum self-assigned this Jun 26, 2024

rdaum force-pushed the rd/scheduler-refactor branch from 8ca1e2e to 6cc434e Compare June 26, 2024 21:22

rdaum force-pushed the rd/scheduler-refactor branch from 6cc434e to 28f480b Compare June 26, 2024 21:24

rdaum added 2 commits June 26, 2024 22:26

Add some basic unit tests for the task logic:

f2d051c

* Run simple program to completion * Throw an exception * `suspend()` and resume * `read()`` and resume * fork

Add unit test for notify() builtin invocation.

68b0f62

rdaum force-pushed the rd/scheduler-refactor branch from 8f70c72 to 68b0f62 Compare June 27, 2024 02:43

Remove unused start time field on Task

80b77b8