README添加实验六和实验七

彩票调度算法

.vscode/c_cpp_properties.json

@@ -6,7 +6,7 @@
                 "${workspaceFolder}/**",
                 // "${workspaceFolder}/labcodes_answer/**/", 
                 // 由于按顺序搜索，所以如果这样的话搜索到lab1_result中的同名头文件就不会引用到lab2_result中的同名头文件导致错误
-                "${workspaceFolder}/labcodes_answer/lab5_result/**/"
+                "${workspaceFolder}/labcodes_answer/lab7_result/**/"
             ],
             "defines": [],
             "compilerPath": "/usr/bin/gcc",

.vscode/launch.json

@@ -11,7 +11,7 @@
             "program": "bin/kernel",
             "args": [],
             "stopAtEntry": false,
-            "cwd": "${workspaceFolder}/labcodes_answer/lab5_result",
+            "cwd": "${workspaceFolder}/labcodes_answer/lab7_result",
             "environment": [],
             "externalConsole": false,
             "MIMode": "gdb",

.vscode/tasks.json

@@ -9,7 +9,7 @@
                 "env": {
                     "DISPLAY": ":0",
                 },
-                "cwd": "${workspaceFolder}/labcodes_answer/lab5_result"
+                "cwd": "${workspaceFolder}/labcodes_answer/lab7_result"
             },
             
             "problemMatcher": [

README.md

@@ -20,4 +20,26 @@
 ### 效果
 ![](assets/实验三演示.gif)
 ### 原理
-在swap_fifo.c文件中，修改_fifo_swap_out_victim（或者新建一个函数）。当需要换出页面时，从链表尾部取出一个页面，如果这个页面的访问位是1，那么将其访问位改为0，并放到链表头部。接着再从链表尾部检测下一个页面，直到找到一个访问位为0页面的作为换出的页面。（测试函数_fifo_check_swap也需要略微更改）
+在swap_fifo.c文件中，修改_fifo_swap_out_victim（或者新建一个函数）。当需要换出页面时，从链表尾部取出一个页面，如果这个页面的访问位是1，那么将其访问位改为0，并放到链表头部。接着再从链表尾部检测下一个页面，直到找到一个访问位为0页面的作为换出的页面。（测试函数_fifo_check_swap也需要略微更改）
+
+## 实验四
+无编程作业。
+
+## 实验五
+无编程作业。
+
+## 实验六
+### 题目
+编程实现理论课中的彩票进程调度算法。（算法的描述以及实现思路可以参考理论课教材和课程PPT）
+### 效果
+![](assets/实验六演示.gif)
+### 原理
+在default_sched.c文件中，新建彩票进程调度的几个函数。将进程的优先级作为彩票数量，在入队和出队时维护运行队列中的优先级总和，当需要选择下一个调度的进程时，从0到优先级总和的范围中选取一个随机数，之后把运行队列中进程优先级逐个相加，直到大于此随机数，这说明此随机数在这个进程拥有的彩票范围内。
+
+## 实验七
+### 题目
+利用信号量机制实现读者写者问题的同步关系。（算法的描述以及实现思路可以参考理论课教材和课程PPT）
+### 效果
+![](assets/实验七演示.gif)
+### 原理
+读者和读者不需要互斥，读者和写者需要互斥，写者和写者需要互斥。维护当前读者数量的变量，当大于0时写者需要等待，当有写者在写时其他进程需要等待。在主进程中随机创建读者进程和写者进程，并随机延迟，这样就能体现出读者和写者在不同情况下的互斥与同步是否正确。

labcodes_answer/lab6_result/Makefile

@@ -253,6 +253,7 @@ endif
 # files for grade script
 
 TARGETS: $(TARGETS)
+all: $(TARGETS)
 
 .DEFAULT_GOAL := TARGETS
 
@@ -268,6 +269,8 @@ qemu-nox: $(UCOREIMG) $(SWAPIMG)
 	$(V)$(QEMU) -serial mon:stdio $(QEMUOPTS) -nographic
 
 TERMINAL := gnome-terminal
+gdb: $(UCOREIMG) $(SWAPIMG)
+	$(V)$(QEMU) -S -s -parallel stdio $(QEMUOPTS) -serial null
 
 debug: $(UCOREIMG) $(SWAPIMG)
 	$(V)$(QEMU) -S -s -parallel stdio $(QEMUOPTS) -serial null &

labcodes_answer/lab6_result/kern/process/proc.c

@@ -820,9 +820,19 @@ user_main(void *arg) {
     panic("user_main execve failed.\n");
 }
 
+static int
+my_test_user_main(void *arg) {
+    int num = (int)arg;
+    int priority = (rand() % 100) * 100;
+    cprintf("process %d, priority %d\n", num, priority);
+    lab6_set_priority(priority);
+    cprintf("process %d end\n", num);
+}
+
 // init_main - the second kernel thread used to create user_main kernel threads
 static int
 init_main(void *arg) {
+    srand((unsigned int)0);
     size_t nr_free_pages_store = nr_free_pages();
     size_t kernel_allocated_store = kallocated();
 
@@ -831,6 +841,16 @@ init_main(void *arg) {
         panic("create user_main failed.\n");
     }
 
+    // error: ‘for’ loop initial declarations are only allowed in C99 mode
+    int i = 0;
+    for (; i < 10; i++) {
+        int pid = kernel_thread(my_test_user_main, (void *)i, 0);
+        if (pid <= 0) {
+            panic("create my_test_user_main failed.\n");
+        }
+        struct proc_strucht *proc = find_proc(pid);
+    }
+
     while (do_wait(0, NULL) == 0) {
         schedule();
     }

labcodes_answer/lab6_result/kern/schedule/default_sched.c

@@ -2,9 +2,10 @@
 #include <list.h>
 #include <proc.h>
 #include <assert.h>
+// #include <time.h> // 没有这个文件
 #include <default_sched.h>
 
-#define USE_SKEW_HEAP 1
+#define USE_SKEW_HEAP 0
 
 /* You should define the BigStride constant here*/
 /* LAB6: YOUR CODE */
@@ -152,6 +153,84 @@ stride_proc_tick(struct run_queue *rq, struct proc_struct *proc) {
      }
 }
 
+static void
+ticket_init(struct run_queue *rq) {
+     list_init(&(rq->run_list));
+     rq->lab6_run_pool = NULL;
+     rq->proc_num = 0;
+}
+
+static void
+ticket_enqueue(struct run_queue *rq, struct proc_struct *proc) {
+     /* LAB6: YOUR CODE */
+#if USE_SKEW_HEAP
+     rq->lab6_run_pool =
+          skew_heap_insert(rq->lab6_run_pool, &(proc->lab6_run_pool), proc_stride_comp_f);
+#else
+     assert(list_empty(&(proc->run_link)));
+     list_add_before(&(rq->run_list), &(proc->run_link));
+#endif
+     if (proc->time_slice == 0 || proc->time_slice > rq->max_time_slice) {
+          proc->time_slice = rq->max_time_slice;
+     }
+     proc->rq = rq;
+     rq->proc_num ++;
+     rq->lab6_total_num += proc->lab6_priority + 1;
+     
+}
+
+static struct proc_struct *
+ticket_pick_next(struct run_queue *rq) {
+     /* LAB6: YOUR CODE */
+     uint32_t target_index = rand() % rq->lab6_total_num;
+#if USE_SKEW_HEAP
+     if (rq->lab6_run_pool == NULL) return NULL;
+     struct proc_struct *p = le2proc(rq->lab6_run_pool, lab6_run_pool);
+#else
+     list_entry_t *le = list_next(&(rq->run_list));
+
+     if (le == &rq->run_list)
+          return NULL;
+
+     struct proc_struct *p;
+     int32_t temp_ticket_sum = 0;
+     while (le != &rq->run_list)
+     {
+          p = le2proc(le, run_link);
+          temp_ticket_sum += p->lab6_priority + 1;
+          if (temp_ticket_sum >= target_index)
+               break;
+          le = list_next(le);
+     }
+#endif
+     return p;
+}
+
+static void
+ticket_dequeue(struct run_queue *rq, struct proc_struct *proc) {
+     /* LAB6: YOUR CODE */
+#if USE_SKEW_HEAP
+     rq->lab6_run_pool =
+          skew_heap_remove(rq->lab6_run_pool, &(proc->lab6_run_pool), proc_stride_comp_f);
+#else
+     assert(!list_empty(&(proc->run_link)) && proc->rq == rq);
+     list_del_init(&(proc->run_link));
+#endif
+     rq->proc_num --;
+     rq->lab6_total_num -= proc->lab6_priority + 1;
+}
+
+static void
+ticket_proc_tick(struct run_queue *rq, struct proc_struct *proc) {
+     /* LAB6: YOUR CODE */
+     if (proc->time_slice > 0) {
+          proc->time_slice --;
+     }
+     if (proc->time_slice == 0) {
+          proc->need_resched = 1;
+     }
+}
+
 struct sched_class default_sched_class = {
      .name = "stride_scheduler",
      .init = stride_init,
@@ -161,3 +240,11 @@ struct sched_class default_sched_class = {
      .proc_tick = stride_proc_tick,
 };
 
+struct sched_class ticket_sched_class = {
+     .name = "ticket_scheduler",
+     .init = ticket_init,
+     .enqueue = ticket_enqueue,
+     .dequeue = ticket_dequeue,
+     .pick_next = ticket_pick_next,
+     .proc_tick = ticket_proc_tick,
+};

labcodes_answer/lab6_result/kern/schedule/default_sched.h

@@ -4,6 +4,7 @@
 #include <sched.h>
 
 extern struct sched_class default_sched_class;
+extern struct sched_class ticket_sched_class;
 
 #endif /* !__KERN_SCHEDULE_SCHED_RR_H__ */
 

labcodes_answer/lab6_result/kern/schedule/sched.c

@@ -46,7 +46,7 @@ void
 sched_init(void) {
     list_init(&timer_list);
 
-    sched_class = &default_sched_class;
+    sched_class = &ticket_sched_class;
 
     rq = &__rq;
     rq->max_time_slice = MAX_TIME_SLICE;

labcodes_answer/lab6_result/kern/schedule/sched.h

@@ -42,6 +42,7 @@ struct run_queue {
     int max_time_slice;
     // For LAB6 ONLY
     skew_heap_entry_t *lab6_run_pool;
+    uint32_t lab6_total_num;
 };
 
 void sched_init(void);

labcodes_answer/lab7_result/Makefile

@@ -253,6 +253,7 @@ endif
 # files for grade script
 
 TARGETS: $(TARGETS)
+all: $(TARGETS)
 
 .DEFAULT_GOAL := TARGETS
 
@@ -268,6 +269,8 @@ qemu-nox: $(UCOREIMG) $(SWAPIMG)
 	$(V)$(QEMU) -serial mon:stdio $(QEMUOPTS) -nographic
 
 TERMINAL := gnome-terminal
+gdb: $(UCOREIMG) $(SWAPIMG)
+	$(V)$(QEMU) -S -s -parallel stdio $(QEMUOPTS) -serial null
 
 debug: $(UCOREIMG) $(SWAPIMG)
 	$(V)$(QEMU) -S -s -parallel stdio $(QEMUOPTS) -serial null &

labcodes_answer/lab7_result/kern/process/proc.c

@@ -844,8 +844,8 @@ init_main(void *arg) {
     if (pid <= 0) {
         panic("create user_main failed.\n");
     }
- extern void check_sync(void);
-    check_sync();                // check philosopher sync problem
+ extern void read_write_sync(void);
+    read_write_sync();                // check philosopher sync problem
 
     while (do_wait(0, NULL) == 0) {
         schedule();

labcodes_answer/lab7_result/kern/sync/read_write_sync.c

@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <proc.h>
+#include <sem.h>
+#include <monitor.h>
+#include <assert.h>
+
+#define READER_NUM 100 // 读者数量，取值应大于1，小于int范围
+#define WRITER_NUM 100 // 写者数量，取值应大于1，小于int范围
+// #define BUFFER_NUM 10 // 缓冲区数量，取值应大于1，小于int范围
+#define SLEEP_TIME 10
+
+// down和up、P和V 都实在是用不习惯，还是用acquire和release吧。
+#define acquire down
+#define release up
+
+semaphore_t mutex; /* 临界区互斥 */
+semaphore_t synchronization; // 同步
+int read_pos_write_neg = 0; // 表示正在读取的读者数量
+int buffer;
+
+int reader(int index){
+    lab6_set_priority(rand() % 100);
+    int result;
+    acquire(&mutex);
+    read_pos_write_neg++;
+    if (read_pos_write_neg == 1)
+        acquire(&synchronization);
+    release(&mutex);
+    do_sleep(rand() % SLEEP_TIME); // 模拟读延迟
+    result = buffer;
+    acquire(&mutex);
+    read_pos_write_neg--;
+    assert(read_pos_write_neg >=0);
+    if (read_pos_write_neg == 0) {
+        release(&synchronization);
+    }
+    release(&mutex);
+    cprintf("reader %2d read   %2d\n", index, result);
+    return result;
+}
+
+void writer(int index) {
+    lab6_set_priority(rand() % 100);
+    int write_data = rand() % 100;
+    acquire(&synchronization);
+    do_sleep(rand() % SLEEP_TIME); // 模拟写延迟
+    buffer = write_data;
+    release(&synchronization);
+    cprintf("writer %2d writed %2d\n", index, write_data);
+}
+
+void read_write_sync() {
+    sem_init(&mutex, 1);
+    sem_init(&synchronization, 1);
+    int reader_num = 0, writer_num = 0;
+    while (reader_num < READER_NUM || writer_num < WRITER_NUM) {
+        if (rand() % 2) {
+            if (reader_num < READER_NUM) {
+                int pid = kernel_thread(reader, (void *)reader_num, 0);
+                if (pid <= 0) {
+                    panic("create No.%d reader failed.\n");
+                }
+                reader_num++;
+            }
+        } else {
+            if (writer_num < WRITER_NUM) {
+                int pid = kernel_thread(writer, (void *)writer_num, 0);
+                if (pid <= 0) {
+                    panic("create No.%d writer failed.\n");
+                }
+                writer_num++;
+            }
+        }
+        do_sleep(rand() % SLEEP_TIME); // 模拟入队延迟
+    }
+}