funnyos/kern/kern_sched.c - diff

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Diff for /funnyos/kern/kern_sched.c between version 1.1 and 1.2

-version 1.1, 2007/11/19 15:54:33
+version 1.2, 2007/11/20 16:07:24
 Line 3
 Line 3
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   */
  #include <sys/types.h>
  #include <sys/kern_sched.h>
+ #include <sys/kern_time.h> /* for HZ */
+ #include <sys/mem.h>
  #include <libkern/printf.h>
+ /* config.c gives us tasks that we'll schedule */
+ extern struct u_task config_tasklist[];
+ /* list of k_tasks */
+ struct k_task *ktasklist;
+ /* pcb of running task; we will save context there when enter irq_mode */
+ uint32_t *curpcb;
+ /* total tasks; used to TID generation */
+ uint8_t ntasks;
+ /* "idle" task exists forever and occupy cpu when there is no other task pretending. */
+ const struct u_task idle_utask = {"idle", 0, NULL};
+ void
+ sched_init(void)
+ {
+         /*
+          * Create struct k_task for each u_task that user described in config_tasklist.
+          */
+         struct u_task *utaskp;
+         struct k_task *ktaskp, *oldktaskp;
+         ntasks = 0;
+         /*
+          * Create an "idle" task which always has TID 0.
+          */
+         ktaskp = kmalloc(sizeof(struct k_task));
+         if (ktaskp == NULL)
+                 panic("can't allocate memory for idle task\n");
+         /* link u_task for idle task */
+         ktaskp->kt_utask = (struct u_task *)&idle_utask;
+         /* TID (always 0) */
+         ktaskp->kt_tid = 0;
+         /* idle task is always in state READY (or RUNNING, if on processor now) */
+         ktaskp->kt_state = TASK_READY;
+         /* next task in list isn't up yet (and prev too) */
+         ktaskp->kt_next = NULL;
+         /* make "idle" task first task in ktasklist, system k_task list */
+         ktasklist = ktaskp;
+         /* bump ntasks to 1 */
+         ntasks = 1;
+         /* preserve pointer to this k_task so we can link-in next task */
+         oldktaskp = ktaskp;
+         /*
+          * Idle task set up completed.
+          * Configure all other system tasks,
+          */
+         /* look through tasklist */
+         utaskp = config_tasklist;
+         while(utaskp->ut_name != NULL) {
+                 /* try to allocate memory for ktask */
+                 ktaskp = kmalloc(sizeof(struct k_task));
+                 if (ktaskp == NULL)
+                         panic("can't allocate memory for task '%s'\n", utaskp->ut_name);
+                 /*
+                  * Successfully allocated new ktask.
+                  */
+                 /* link u_task */
+                 ktaskp->kt_utask = utaskp;
+                 /* set TID (Task Identificator) */
+                 ktaskp->kt_tid = oldktaskp->kt_tid + 1;
+                 /* state */
+                 ktaskp->kt_state = TASK_READY;
+                 /* link current task in previous task's structure */
+                 oldktaskp->kt_next = ktaskp;
+                 /* NULLify kt_next of current task */
+                 ktaskp->kt_next = NULL;
+                 /* save current ktask for use with next ktask */
+                 oldktaskp = ktaskp;
+                 /* bump ntasks */
+                 ntasks++;
+                 /* shift to next element in config_tasklist[] */
+                 utaskp++;
+         }
+         /* make this list circularly linked (e.g point list's last->next node into first) */
+         ktaskp->kt_next = ktasklist;
+         printf("kern_sched: created %d tasks:", ntasks);
+         /* print tasks' names */
+         ktaskp = ktasklist + 1; /* skip (first) "idle" task (display it as the end of circularly list) */
+         do {
+                 printf(" %s", ktaskp->kt_utask->ut_name);
+                 if (ktaskp->kt_tid == NULL) /* that was an "idle" task */
+                         break;
+                 ktaskp = ktaskp->kt_next;
+         } while(1);
+         printf("; HZ=%d\n", HZ);
+ }

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