82 lines
6.3 KiB
Markdown
82 lines
6.3 KiB
Markdown
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---
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title: "scheduler.h"
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summary: "the scheduler is responsible for switching between threads and controlling processes"
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---
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#### `scheduler_processes_chunk_T` - struct
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These chunks are a combination of static array and linked list.
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They store the [process_T](https://nerdcult.net/projects/noxos/docs/codebase/proc/process.h/#process_t---struct) pointer for each valid `pid_t`.
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[scheduler_processes_chunk_T](https://nerdcult.net/projects/noxos/docs/codebase/proc/scheduler.h/#scheduler_processes_chunk_t---struct)
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| Name | Type | Description |
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|------------------|------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------|
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| processes | [process_T](https://nerdcult.net/projects/noxos/docs/codebase/proc/process.h/#process_t---struct)** | The array of process pointers |
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| processes_bitmap | bitmap_T(reference needed) | If a bit in this bitmap is set, the _processes_ entry with the same index is valid |
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| num_free_pids | uint32_t | The amount of free slots in this chunk |
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| prev | [scheduler_processes_chunk_T](https://nerdcult.net/projects/noxos/docs/codebase/proc/scheduler.h/#scheduler_processes_chunk_t---struct)* | The previous chunk |
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| next | [scheduler_processes_chunk_T](https://nerdcult.net/projects/noxos/docs/codebase/proc/scheduler.h/#scheduler_processes_chunk_t---struct)* | The next chunk |
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#### `scheduler_T` - struct
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| Name | Type | Description |
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|----------------|------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------|
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| num_threads | uint32_t | Total amount of currently spawned threads |
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| num_processes | uint32_t | Total amount of currently spawned processes |
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| running_thread | [thread_T](https://nerdcult.net/projects/noxos/docs/codebase/proc/thread.h/#thread_t---struct)* | A pointer to the currently running thread. |
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| processes | [scheduler_processes_chunk_T](https://nerdcult.net/projects/noxos/docs/codebase/proc/scheduler.h/#scheduler_processes_chunk_t---struct)* | The first processes store chunk |
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| blocked | bool | Set to true, while switching the context. Thread safety mechanism. |
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| initialized | bool | Set to true, if the scheduler is initialized and started. |
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#### `scheduler_init(boot_info)` - function (void)
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Initializes the scheduler and performs a `nx_scheduler_start` kernel syscall.
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**_boot_info_** is needed in to spawn the kernels' main process.
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After this function, the whole kernel is in scheduling mode.
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#### `scheduler_start(state)` - function (cpu_state_T*)
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Creates and starts a thread from **_state_**.
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It returns the result of a context switch, I forgot, why I did it like that.
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This is basically the backend for the `nx_scheduler_start` kernel syscall.
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#### `scheduler_is_initialized()` - function (bool)
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Returns if the scheduler is initialized (and running) or not.
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#### `scheduler_dump_info(process, indent)` - function (void)
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This recursively lists information(pid, name, threads) for all child processes of **_process_**.
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**_indent_** is used intern for the recursive calls and should be set to 0 initially.
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#### `scheduler_register_thread(thread)` - function (thread_T*)
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Registers **_thread_** in the scheduler.
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#### `scheduler_pause_thread(thread)` - function (void)
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Pauses **_thread_**, by removing it from the scheduling queue.
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**Potential Bug:** if **_thread_** was the currently running thread,
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this could cause issues, because it's _prev_ and _next_ values are nulled.
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#### `scheduler_start_thread(thread)` - function (void)
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Starts **_thread_**, by linking it into the scheduling queue.
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#### `scheduler_kill_thread(thread)` - function (void)
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Pauses and unregisters **_thread_**.
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#### `scheduler_register_process(process)` - function (pid_t)
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Reqisters **_process_** and returns its pid.
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#### `scheduler_kill_process(process)` - function (void)
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Kills **_process_** and its threads and childs.
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#### `scheduler_get_process(pid)` - function (process_T*)
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Returns the `process_T` pointer that is associated with **_pid_**.
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#### `scheduler_get_current_thread()` - function (thread_T*)
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Returns a pointer to the currently running thread.
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#### `scheduler_get_current_process()` - function (process_T*)
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Returns a pointer to the currently running threads process.
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#### `scheduler_switch_context(state)` - function (cpu_state_T*)
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Saves **_state_** in the running threads _state_ value and increments their _cpu_time_ value.
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Then it sets the next thread as the running thread and returns its _state_.
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This needs to be called from an interrupt handler, for the returned state to be loaded.
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