进程调度

wanggx · Mar 25, 2016 · 638c439 · 638c439
1 parent 483812c
commit 638c439
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Showing 7 changed files with 11 additions and 1 deletion.
diff --git a/Kernel1.0.PFI b/Kernel1.0.PFI
diff --git a/Kernel1.0.PO b/Kernel1.0.PO
diff --git a/Kernel1.0.PS b/Kernel1.0.PS
diff --git a/Kernel1.0.WK3 b/Kernel1.0.WK3
diff --git a/Linux1.0/include/linux/kernel_stat.h b/Linux1.0/include/linux/kernel_stat.h
@@ -9,6 +9,7 @@
 
 #define DK_NDRIVE 4
 
+/* ¼ÇÂ¼ÄÚºË×´Ì¬ */
 struct kernel_stat {
 	unsigned int cpu_user, cpu_nice, cpu_system;
 	unsigned int dk_drive[DK_NDRIVE];

diff --git a/Linux1.0/include/linux/sched.h b/Linux1.0/include/linux/sched.h
@@ -408,7 +408,7 @@ __asm__("str %%ax\n\t" \
  * This also clears the TS-flag if the task we switched to has used
  * tha math co-processor latest.
  */
-/* current在这个时候被改变
+/* current在这个时候被改变，也就是切换到tsk这个进程
  */
 #define switch_to(tsk) \
 __asm__("cmpl %%ecx,_current\n\t" \

diff --git a/Linux1.0/kernel/sched.c b/Linux1.0/kernel/sched.c
@@ -208,6 +208,9 @@ static unsigned long lost_ticks = 0;
  * The "confuse_gcc" goto is used only to get better assembly code..
  * Djikstra probably hates me.
  */
+
+/* 进程调度函数
+ */
 asmlinkage void schedule(void)
 {
 	int c;
@@ -225,6 +228,7 @@ asmlinkage void schedule(void)
 	need_resched = 0;
 	p = &init_task;
 	for (;;) {
+        /* 保证进程链表只扫描一圈 */
 		if ((p = p->next_task) == &init_task)
 			goto confuse_gcc1;
 		if (ticks && p->it_real_value) {
@@ -243,8 +247,13 @@ asmlinkage void schedule(void)
 				itimer_next = p->it_real_value;
 		}
 end_itimer:
+        /* 如果进程是非可中断状态，则在选择调度的程序时，不考虑该进程，
+           * 如进程陷入一种不可中断的睡眠状态，则此时调度程序不可调度该进程
+           */
 		if (p->state != TASK_INTERRUPTIBLE)
 			continue;
+        /* 如果进程接收到了信号，则设置进程的状态为运行态
+           */
 		if (p->signal & ~p->blocked) {
 			p->state = TASK_RUNNING;
 			continue;