Re: [PATCH for 2.5] preemptible kernel

[Roger Larsson]

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
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