Re: [PATCH for 2.5] preemptible kernel

[Roger Larsson <roger.larsson@norran.net>]

Hi,

One little readability thing I found.
The prev->state TASK_ value is mostly used as a plain value
but the new TASK_PREEMPTED is or:ed together with whatever was there.
Later when we switch to check the state it is checked against TASK_PREEMPTED
only. Since TASK_RUNNING is 0 it works OK but...

--- sched.c.nigel       Tue Mar 20 18:52:43 2001
+++ sched.c.roger       Tue Mar 20 19:03:28 2001
@@ -553,7 +553,7 @@
 #endif
                        del_from_runqueue(prev);
 #ifdef CONFIG_PREEMPT
-               case TASK_PREEMPTED:
+               case TASK_RUNNING | TASK_PREEMPTED:
 #endif
                case TASK_RUNNING:
        }


We could add all/(other common) combinations as cases 

	switch (prev->state) {
		case TASK_INTERRUPTIBLE:
			if (signal_pending(prev)) {
				prev->state = TASK_RUNNING;
				break;
			}
		default:
#ifdef CONFIG_PREEMPT
			if (prev->state & TASK_PREEMPTED)
				break;
#endif
			del_from_runqueue(prev);
#ifdef CONFIG_PREEMPT
		case TASK_RUNNING		| TASK_PREEMPTED:
		case TASK_INTERRUPTIBLE	| TASK_PREEMPTED:
		case TASK_UNINTERRUPTIBLE	| TASK_PREEMPTED:
#endif
		case TASK_RUNNING:
	}


Then the break in default case could almost be replaced with a BUG()...
(I have not checked the generated code)

/RogerL