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Avoid Arc instances in switch_to

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Ruihan Li 2024-11-19 23:59:29 +08:00 committed by Tate, Hongliang Tian
parent c8c9b9753e
commit 9b38eff5fe
1 changed files with 6 additions and 11 deletions
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17
ostd/src/task/processor.rs
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@ -39,19 +39,14 @@ pub(super) fn switch_to_task(next_task: Arc<Task>) {
let irq_guard = crate::trap::disable_local();
let current_task_ptr = CURRENT_TASK_PTR.load();
let current_task_ctx_ptr = if current_task_ptr.is_null() {
let current_task_ctx_ptr = if !current_task_ptr.is_null() {
// SAFETY: The current task is always alive.
let current_task = unsafe { &*current_task_ptr };
// Throughout this method, the task's context is alive and can be exclusively used.
current_task.ctx.get()
} else {
// SAFETY: Interrupts are disabled, so the pointer is safe to be fetched.
unsafe { BOOTSTRAP_CONTEXT.as_ptr_mut() }
} else {
// SAFETY: The pointer is not NULL and set as the current task.
let cur_task_arc = unsafe {
let restored = Arc::from_raw(current_task_ptr);
let _ = core::mem::ManuallyDrop::new(restored.clone());
restored
};
let ctx_ptr = cur_task_arc.ctx().get();
ctx_ptr
};
let next_task_ctx_ptr = next_task.ctx().get().cast_const();