Module os::task

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Implementation of process ProcessControlBlock and task(thread) TaskControlBlock management mechanism

Here is the entry for task scheduling required by other modules (such as syscall or clock interrupt). By suspending or exiting the current task, you can modify the task state, manage the task queue through TASK_MANAGER (in task/manager.rs) , and switch the control flow through PROCESSOR (in task/processor.rs) .

Be careful when you see __switch. Control flow around this function might not be what you expect.

Modules

context 🔒

Implementation of TaskContext

id 🔒

Allocator for pid, task user resource, kernel stack using a simple recycle strategy.

manager 🔒

Implementation of TaskManager

process 🔒

Implementation of ProcessControlBlock

Implementation of Processor and Intersection of control flow

signal 🔒

Signal flags and function for convert signal flag to integer & string

switch 🔒

provides __switch asm function to switch between two task contexts TaskContext

task 🔒

Types related to task management & Functions for completely changing TCB

Structs

Creation of initial process

Kernel stack for a task

A handle to a pid

Signal flags

task context structure containing some registers

TaskControlBlock

Task control block structure

Enums

The execution status of the current process

Constants

The idle task’s pid is 0

Functions

Add init process to the manager

Add a task to ready queue

block_current_and_run_next

Make current task blocked and switch to the next task.

check_signals_of_current

Check if the current task has any signal to handle

current_add_signal

Add signal to the current task

current_kstack_top

get the top addr of kernel stack

current_process

get current process

Get a copy of the current task

current_trap_cx

Get the mutable reference to trap context of current task

current_trap_cx_user_va

get the user virtual address of trap context

current_user_token

Get the current user token(addr of page table)

exit_current_and_run_next

Exit the current ‘Running’ task and run the next task in task list.

Allocate a kernel stack for a task

Get process by pid

Allocate a pid for a process

remove_from_pid2process

Remove item(pid, _some_pcb) from PDI2PCB map (called by exit_current_and_run_next)

remove_inactive_task

the inactive(blocked) tasks are removed when the PCB is deallocated.(called by exit_current_and_run_next)

Remove a task from the ready queue

The main part of process execution and scheduling Loop fetch_task to get the process that needs to run, and switch the process through __switch

Return to idle control flow for new scheduling

suspend_current_and_run_next

Make current task suspended and switch to the next task

take_current_task

Get current task through take, leaving a None in its place

Wake up a task