Make context switching much more MI:

 - Move the functionality of choosing a process from cpu_switch into
   a much simpler function: cpu_switchto. Instead of having the locore
   code walk the run queues, let the MI code choose the process we
   want to run and only implement the context switching itself in MD
   code.
 - Let MD context switching run without worrying about spls or locks.
 - Instead of having the idle loop implemented with special contexts
   in MD code, implement one idle proc for each cpu. make the idle
   loop MI with MD hooks.
 - Change the proc lists from the old style vax queues to TAILQs.
 - Change the sleep queue from vax queues to TAILQs. This makes
   wakeup() go from O(n^2) to O(n)

there will be some MD fallout, but it will be fixed shortly.
There's also a few cleanups to be done after this.

deraadt@, kettenis@ ok

1 files changed, 4 insertions, 14 deletions

diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index 4c85dd84543..fa68a37f72a 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_exit.c,v 1.71 2007/04/12 22:14:15 tedu Exp $	*/
+/*	$OpenBSD: kern_exit.c,v 1.72 2007/10/10 15:53:53 art Exp $	*/
 /*	$NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $	*/
 
 /*
@@ -315,16 +315,8 @@ exit1(struct proc *p, int rv, int flags)
 	sigactsfree(p);
 
 	/*
-	 * Clear curproc after we've done all operations
-	 * that could block, and before tearing down the rest
-	 * of the process state that might be used from clock, etc.
-	 * Also, can't clear curproc while we're still runnable,
-	 * as we're not on a run queue (we are current, just not
-	 * a proper proc any longer!).
-	 *
-	 * Other substructures are freed from wait().
+	 * Other substructures are freed from reaper and wait().
 	 */
-	curproc = NULL;
 
 	/*
 	 * If emulation has process exit hook, call it now.
@@ -373,15 +365,11 @@ struct proclist deadproc = LIST_HEAD_INITIALIZER(deadproc);
 void
 exit2(struct proc *p)
 {
-	int s;
-
 	mtx_enter(&deadproc_mutex);
 	LIST_INSERT_HEAD(&deadproc, p, p_hash);
 	mtx_leave(&deadproc_mutex);
 
 	wakeup(&deadproc);
-
-	SCHED_LOCK(s);
 }
 
 /*
@@ -396,6 +384,8 @@ reaper(void)
 
 	KERNEL_PROC_UNLOCK(curproc);
 
+	SCHED_ASSERT_UNLOCKED();
+
 	for (;;) {
 		mtx_enter(&deadproc_mutex);
 		p = LIST_FIRST(&deadproc);