block.cpp

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#include <cassert>
 
#include "kernel_log.hpp"
#include "resource_id.hpp"
#include "task_manager.hpp"
#include "task_messages.hpp"
 
auto TaskManager::Block(ResourceId resource_id) -> void {
  auto& cpu_sched = GetCurrentCpuSched();
 
  auto* current = GetCurrentTask();
  assert(current != nullptr && "Block: No current task to block");
  assert(current->GetStatus() == TaskStatus::kRunning &&
         "Block: current task status must be kRunning");
 
  {
    LockGuard<SpinLock> lock_guard(cpu_sched.lock);
 
    // Check capacity before transitioning FSM
    auto& list = cpu_sched.blocked_tasks[resource_id];
    if (list.full()) {
      klog::Err(
          "Block: blocked_tasks list full for resource, cannot block task {}",
          current->pid);
      // Rollback: task stays kRunning, do not transition FSM
      return;
    }
 
    // Transition: kRunning -> kBlocked
    current->fsm.Receive(MsgBlock{resource_id});
    // Record blocked resource
    current->aux->blocked_on = resource_id;
    list.push_back(current);
 
    klog::Debug("Block: pid={} blocked on resource={}, data={:#x}",
                current->pid, resource_id.GetTypeName(),
                static_cast<uint64_t>(resource_id.GetData()));
  }
 
  // 调度到其他任务
  Schedule();
 
  // 任务被唤醒后会从这里继续执行
}