From 39b1f14b29ba578cc75475f42a5cee864394a97d Mon Sep 17 00:00:00 2001
From: "Michael D. Lowis" <mike@mdlowis.com>
Date: Thu, 8 Sep 2022 23:25:59 -0400
Subject: [PATCH] minor refactoring

---
 tasks.c | 87 ++++++++++++++++++++++++++++-----------------------------
 1 file changed, 42 insertions(+), 45 deletions(-)

diff --git a/tasks.c b/tasks.c
index b54d65d..6cb1ca3 100644
--- a/tasks.c
+++ b/tasks.c
@@ -36,7 +36,6 @@ typedef struct {
 static pthread_mutex_t ScheduleLock;
 static pthread_cond_t ScheduleCond;
 static __thread int CpuID = 0;
-static long int TaskCount = 0;
 static TaskQueue_T ReadyQueue = {0};
 static TaskQueue_T DeadQueue = {0};
 static CpuState_T* Running = NULL;
@@ -178,12 +177,12 @@ static void Yield(void)
     SwapTask(prev, Running[CpuID].task);
 }
 
-void FinalizeTask(void)
+void ExitTask(void)
 {
     puts("exiting");
     AcquireLock();
-    TaskCount--;
-    Running[CpuID].task = NULL; // TODO: Enqueue to dead queue
+    Enqueue(&DeadQueue, Running[CpuID].task);
+    Running[CpuID].task = NULL;
     Running[CpuID].task = Select();
     printf("starting task %p\n", Running[CpuID].task);
     ReleaseLock();
@@ -196,7 +195,7 @@ static Task_T* CreateTask(void (*task_fn)(void*), void* arg, int stacksize)
     Task_T* task = calloc(1, sizeof(Task_T));
     task->stack_base = calloc(stacksize/sizeof(long), sizeof(long));
     task->stack_top  = &task->stack_base[stacksize/sizeof(long)-1]; // top of stack
-    *(--task->stack_top) = (long)FinalizeTask; // coroutine cleanup
+    *(--task->stack_top) = (long)ExitTask; // coroutine cleanup
     *(--task->stack_top) = (long)task_fn;   // user's function to run (rop style!)
     *(--task->stack_top) = (long)arg;       // user's function argument (rdi)
     for (int saved = 0; saved < 6; saved++)
@@ -212,7 +211,6 @@ void SpawnTask(void (*task_fn)(void*), void* arg, int stacksize)
     Task_T* task = CreateTask(task_fn, arg, stacksize);
     /* put task in the ready queue */
     AcquireLock();
-    TaskCount++;
     Enter(task);
     ReleaseLock();
 }
@@ -225,7 +223,7 @@ static void CpuIdle(void* arg)
         Yield();
         printf("CPU %d is idle\n", CpuID);
         AcquireLock();
-        WaitForCondition(&ScheduleCond, &ScheduleLock, 1);
+        WaitForCondition(&ScheduleCond, &ScheduleLock, 10);
         ReleaseLock();
     }
 }
@@ -240,6 +238,40 @@ static void* CpuMain(void* arg)
     return NULL; /* unreachable */
 }
 
+void Init(void)
+{
+    pthread_mutex_init(&ScheduleLock, 0);
+    pthread_cond_init(&ScheduleCond, NULL);
+    CpuCount = sysconf(_SC_NPROCESSORS_ONLN);
+    Running = calloc(CpuCount, sizeof(CpuState_T));
+    for (long int i = 0; i < CpuCount; i++)
+    {
+        pthread_create(&Running[i].thread, NULL, CpuMain, (void*)i);
+    }
+}
+
+void WaitForExit(void)
+{
+    while(1)
+    {
+        AcquireLock();
+        WaitForCondition(&ScheduleCond, &ScheduleLock, 10);
+        if (!ReadyQueue.head)
+        {
+            bool done = true;
+            for (long int i = 0; i < CpuCount; i++)
+            {
+                done = done && (Running[i].task == Running[i].idle);
+            }
+            if (done)
+            {
+                break;
+            }
+        }
+        ReleaseLock();
+    }
+}
+
 /***************************************
     Main Routine
 ***************************************/
@@ -267,49 +299,14 @@ int main(int argc, char** argv)
     (void)argc;
     (void)argv;
 
-    pthread_mutex_init(&ScheduleLock, 0);
-    pthread_cond_init(&ScheduleCond, NULL);
-    CpuCount = sysconf(_SC_NPROCESSORS_ONLN);
-//    CpuCount = 1;
-    Running = calloc(CpuCount, sizeof(CpuState_T));
-    for (long int i = 0; i < CpuCount; i++)
-    {
-        pthread_create(&Running[i].thread, NULL, CpuMain, (void*)i);
-    }
+    Init();
 
     SpawnTask(task1, 0, 0);
     SpawnTask(task2, 0, 0);
 
     /* wait for all jobs to be done */
-    while(1)
-    {
-        AcquireLock();
-        WaitForCondition(&ScheduleCond, &ScheduleLock, 10);
-//        printf("%ld %d %p\n", TaskCount, CpuCount, ReadyQueue.head);
-        if (TaskCount == 0)
-        {
-            break;
-        }
-//        else
-        {
-            printf("count: %ld\n", TaskCount);
-            printf("head:  %p\n", ReadyQueue.head);
-            printf("tasks:\n");
-            for (long int i = 0; i < CpuCount; i++)
-            {
-                if (Running[i].task == Running[i].idle)
-                {
-                    printf("    %02ld idle\n", i);
-                }
-                else
-                {
-                    printf("    %02ld %p\n", i, Running[i].task);
-                }
-            }
-
-        }
-        ReleaseLock();
-    }
+    WaitForExit();
     puts("done");
+
     return 0;
 }
\ No newline at end of file
-- 
2.54.0