Proc refcnting wrappers

[akaros.git] / kern / src / schedule.c

diff --git a/kern/src/schedule.c b/kern/src/schedule.c
index 7ab2d9e..fe68161 100644 (file)
--- a/kern/src/schedule.c
+++ b/kern/src/schedule.c
@@ -20,8 +20,8 @@
 
 // This could be useful for making scheduling decisions.  
 /* Physical coremap: each index is a physical core id, with a proc ptr for
- * whoever *should be or is* running.  Very similar to current / curenvs[],
- * which is what process is *really* running there. */
+ * whoever *should be or is* running.  Very similar to current, which is what
+ * process is *really* running there. */
 struct proc *pcoremap[MAX_NUM_CPUS];
 
 void schedule_init(void)
@@ -32,19 +32,27 @@ void schedule_init(void)
 
 void schedule_proc(struct proc *p)
 {
+       /* up the refcnt since we are storing the reference */
+       proc_incref(p, 1);
        spin_lock_irqsave(&runnablelist_lock);
-       printd("Scheduling PID: %d\n", p->env_id);
+       printd("Scheduling PID: %d\n", p->pid);
        TAILQ_INSERT_TAIL(&proc_runnablelist, p, proc_link);
        spin_unlock_irqsave(&runnablelist_lock);
        return;
 }
 
+/* TODO: race here.  it's possible that p was already removed from the
+ * list (by schedule()), while proc_destroy is trying to remove it from the
+ * list.  schedule()'s proc_run() won't actually run it (since it's DYING), but
+ * this code will probably fuck up.  Having TAILQ_REMOVE not hurt will help. */
 void deschedule_proc(struct proc *p)
 {
        spin_lock_irqsave(&runnablelist_lock);
-       printd("Descheduling PID: %d\n", p->env_id);
+       printd("Descheduling PID: %d\n", p->pid);
        TAILQ_REMOVE(&proc_runnablelist, p, proc_link);
        spin_unlock_irqsave(&runnablelist_lock);
+       /* down the refcnt, since its no longer stored */
+       proc_decref(p);
        return;
 }
 
@@ -62,13 +70,12 @@ void schedule(void)
        if (p) {
                TAILQ_REMOVE(&proc_runnablelist, p, proc_link);
                spin_unlock_irqsave(&runnablelist_lock);
-               printd("PID of proc i'm running: %d\n", p->env_id);
+               printd("PID of proc i'm running: %d\n", p->pid);
+               /* proc_run will either eat the ref, or we'll decref manually. */
                proc_run(p);
+               proc_decref(p);
        } else {
                spin_unlock_irqsave(&runnablelist_lock);
-               printk("No processes to schedule, enjoy the Monitor!\n");
-               while (1)
-                       monitor(NULL);
        }
        return;
 }
@@ -77,6 +84,6 @@ void dump_proclist(struct proc_list *list)
 {
        struct proc *p;
        TAILQ_FOREACH(p, list, proc_link)
-               printk("PID: %d\n", p->env_id);
+               printk("PID: %d\n", p->pid);
        return;
 }