A couple of SMP deadlock patches

Included below are two patches for two different potential deadlocks on SMP.  
The first one I have sent to the list before, but it didn't seem to help 
anyone.  I do believe it is a fix for a possible deadlock though so I'd like 
some more testing feedback with the aim of committing it.  The second patch 
works around a lock order reversal introduced with the sleep queue code 
(since sched_lock's scope was reduced) at the expense of increasing the 
latency between a swapped out thread becoming runnable and the swapper waking 
up to swap the process back in.

Index: i386/i386/pmap.c
===================================================================
RCS file: /usr/cvs/src/sys/i386/i386/pmap.c,v
retrieving revision 1.488
diff -u -r1.488 pmap.c
--- i386/i386/pmap.c	18 Jul 2004 21:19:10 -0000	1.488
+++ i386/i386/pmap.c	19 Jul 2004 17:15:57 -0000
_at__at_ -185,9 +185,6 _at__at_
 LIST_HEAD(pmaplist, pmap);
 static struct pmaplist allpmaps;
 static struct mtx allpmaps_lock;
-#ifdef SMP
-static struct mtx lazypmap_lock;
-#endif
 
 vm_paddr_t avail_end;	/* PA of last available physical page */
 vm_offset_t virtual_avail;	/* VA of first avail page (after kernel bss) */
_at__at_ -332,9 +329,6 _at__at_
 	kernel_pmap->pm_active = -1;	/* don't allow deactivation */
 	TAILQ_INIT(&kernel_pmap->pm_pvlist);
 	LIST_INIT(&allpmaps);
-#ifdef SMP
-	mtx_init(&lazypmap_lock, "lazypmap", NULL, MTX_SPIN);
-#endif
 	mtx_init(&allpmaps_lock, "allpmaps", NULL, MTX_SPIN);
 	mtx_lock_spin(&allpmaps_lock);
 	LIST_INSERT_HEAD(&allpmaps, kernel_pmap, pm_list);
_at__at_ -1303,7 +1297,7 _at__at_
 	while ((mask = pmap->pm_active) != 0) {
 		spins = 50000000;
 		mask = mask & -mask;	/* Find least significant set bit */
-		mtx_lock_spin(&lazypmap_lock);
+		mtx_lock_spin(&smp_tlb_mtx);
 #ifdef PAE
 		lazyptd = vtophys(pmap->pm_pdpt);
 #else
_at__at_ -1323,7 +1317,7 _at__at_
 					break;
 			}
 		}
-		mtx_unlock_spin(&lazypmap_lock);
+		mtx_unlock_spin(&smp_tlb_mtx);
 		if (spins == 0)
 			printf("pmap_lazyfix: spun for 50000000\n");
 	}
Index: kern/kern_synch.c
===================================================================
RCS file: /usr/cvs/src/sys/kern/kern_synch.c,v
retrieving revision 1.254
diff -u -r1.254 kern_synch.c
--- kern/kern_synch.c	16 Jul 2004 21:04:55 -0000	1.254
+++ kern/kern_synch.c	28 Jul 2004 16:33:45 -0000
_at__at_ -402,7 +402,9 _at__at_
 	if ((p->p_sflag & PS_INMEM) == 0) {
 		if ((p->p_sflag & PS_SWAPPINGIN) == 0) {
 			p->p_sflag |= PS_SWAPINREQ;
+#ifndef SMP
 			wakeup(&proc0);
+#endif
 		}
 	} else
 		sched_wakeup(td);

-- 
John Baldwin <jhb_at_FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org