ch6

Author: xushanpu123

os/loader.c

@@ -64,5 +64,6 @@ int load_init_app()
 	argv[0] = INIT_PROC;
 	argv[1] = NULL;
 	p->trapframe->a0 = push_argv(p, argv);
+	add_task(p);
 	return 0;
 }

os/proc.c

@@ -3,6 +3,7 @@
 #include "loader.h"
 #include "trap.h"
 #include "vm.h"
+#include "queue.h"
 
 struct proc pool[NPROC];
 __attribute__((aligned(16))) char kstack[NPROC][PAGE_SIZE];
@@ -11,6 +12,7 @@ __attribute__((aligned(4096))) char trapframe[NPROC][TRAP_PAGE_SIZE];
 extern char boot_stack_top[];
 struct proc *current_proc;
 struct proc idle;
+struct queue task_queue;
 
 int threadid()
 {
@@ -39,6 +41,7 @@ void proc_init()
 	idle.kstack = (uint64)boot_stack_top;
 	idle.pid = IDLE_PID;
 	current_proc = &idle;
+	init_queue(&task_queue);
 }
 
 int allocpid()
@@ -47,6 +50,24 @@ int allocpid()
 	return PID++;
 }
 
+struct proc *fetch_task()
+{
+	int index = pop_queue(&task_queue);
+	if (index < 0) {
+		debugf("No task to fetch\n");
+		return NULL;
+	}
+	debugf("fetch task %d(pid=%d) from task queue\n", index,
+	       pool[index].pid);
+	return pool + index;
+}
+
+void add_task(struct proc *p)
+{
+	push_queue(&task_queue, p - pool);
+	debugf("add task %d(pid=%d) to task queue\n", p - pool, p->pid);
+}
+
 // Look in the process table for an UNUSED proc.
 // If found, initialize state required to run in the kernel.
 // If there are no free procs, or a memory allocation fails, return 0.
@@ -98,19 +119,27 @@ void scheduler()
 {
 	struct proc *p;
 	for (;;) {
-		int has_proc = 0;
+		/*int has_proc = 0;
 		for (p = pool; p < &pool[NPROC]; p++) {
 			if (p->state == RUNNABLE) {
 				has_proc = 1;
-				debugf("swtich to proc %d", p - pool);
+				tracef("swtich to proc %d", p - pool);
 				p->state = RUNNING;
 				current_proc = p;
 				swtch(&idle.context, &p->context);
 			}
 		}
 		if(has_proc == 0) {
 			panic("all app are over!\n");
+		}*/
+		p = fetch_task();
+		if (p == NULL) {
+			panic("all app are over!\n");
 		}
+		tracef("swtich to proc %d", p - pool);
+		p->state = RUNNING;
+		current_proc = p;
+		swtch(&idle.context, &p->context);
 	}
 }
 
@@ -133,6 +162,7 @@ void sched()
 void yield()
 {
 	current_proc->state = RUNNABLE;
+	add_task(current_proc);
 	sched();
 }
 
@@ -186,6 +216,7 @@ int fork()
 	np->trapframe->a0 = 0;
 	np->parent = p;
 	np->state = RUNNABLE;
+	add_task(np);
 	return np->pid;
 }
 
@@ -266,6 +297,7 @@ int wait(int pid, int *code)
 			return -1;
 		}
 		p->state = RUNNABLE;
+		add_task(p);
 		sched();
 	}
 }

os/proc.h

@@ -43,7 +43,8 @@ struct proc {
 	uint64 max_page;
 	struct proc *parent; // Parent process
 	uint64 exit_code;
-	struct file *files[FD_BUFFER_SIZE]; //File descriptor table, using to record the files opened by the process
+	struct file *files
+		[FD_BUFFER_SIZE]; //File descriptor table, using to record the files opened by the process
 };
 
 int cpuid();
@@ -56,6 +57,8 @@ void yield();
 int fork();
 int exec(char *, char **);
 int wait(int, int *);
+void add_task(struct proc *);
+struct proc *pop_task();
 struct proc *allocproc();
 int fdalloc(struct file *);
 int init_stdio(struct proc *);

os/queue.c

@@ -0,0 +1,29 @@
+#include "queue.h"
+#include "defs.h"
+
+void init_queue(struct queue *q)
+{
+	q->front = q->tail = 0;
+	q->empty = 1;
+}
+
+void push_queue(struct queue *q, int value)
+{
+	if (!q->empty && q->front == q->tail) {
+		panic("queue shouldn't be overflow");
+	}
+	q->empty = 0;
+	q->data[q->tail] = value;
+	q->tail = (q->tail + 1) % NPROC;
+}
+
+int pop_queue(struct queue *q)
+{
+	if (q->empty)
+		return -1;
+	int value = q->data[q->front];
+	q->front = (q->front + 1) % NPROC;
+	if (q->front == q->tail)
+		q->empty = 1;
+	return value;
+}

os/queue.h

@@ -0,0 +1,18 @@
+#ifndef QUEUE_H
+#define QUEUE_H
+#define QUEUE_SIZE (1024)
+
+// TODO: change the queue to a priority queue sorted by priority
+
+struct queue {
+	int data[QUEUE_SIZE];
+	int front;
+	int tail;
+	int empty;
+};
+
+void init_queue(struct queue *);
+void push_queue(struct queue *, int);
+int pop_queue(struct queue *);
+
+#endif // QUEUE_H

os/syscall.c

@@ -142,6 +142,18 @@ uint64 sys_wait(int pid, uint64 va)
 	return wait(pid, code);
 }
 
+uint64 sys_spawn(uint64 va)
+{
+	// TODO: your job is to complete the sys call
+	return -1;
+}
+
+uint64 sys_set_priority(long long prio)
+{
+	// TODO: your job is to complete the sys call
+	return -1;
+}
+
 uint64 sys_openat(uint64 va, uint64 omode, uint64 _flags)
 {
 	struct proc *p = curr_proc();
@@ -235,6 +247,8 @@ void syscall()
 		break;
 	case SYS_unlinkat:
 	    ret = sys_unlinkat(args[0],args[1],args[2]);
+	case SYS_spawn:
+		ret = sys_spawn(args[0]);
 		break;
 	default:
 		ret = -1;

os/syscall_ids.h

@@ -277,6 +277,7 @@
 #define SYS_io_pgetevents 292
 #define SYS_rseq 293
 #define SYS_kexec_file_load 294
+#define SYS_spawn 400
 #define SYS_pidfd_send_signal 424
 #define SYS_io_uring_setup 425
 #define SYS_io_uring_enter 426