Index: src/sys/alpha/alpha/mp_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/alpha/alpha/mp_machdep.c,v
retrieving revision 1.23
diff -u -r1.23 mp_machdep.c
--- src/sys/alpha/alpha/mp_machdep.c	2001/07/14 21:37:57	1.23
+++ src/sys/alpha/alpha/mp_machdep.c	2001/07/22 21:45:04
@@ -301,6 +301,11 @@
 
 	/* XXX: Need to check for valid platforms here. */
 
+	boot_cpu_id = PCPU_GET(cpuid);
+	KASSERT(boot_cpu_id == hwrpb->rpb_primary_cpu_id,
+	    ("cpu_mp_probe() called on non-primary CPU"));
+	all_cpus = 1 << boot_cpu_id;
+
 	mp_ncpus = 1;
 
 	/* Make sure we have at least one secondary CPU. */
@@ -324,16 +329,12 @@
 }
 
 void
-cpu_mp_start()
+cpu_mp_start(void)
 {
 	int i;
 
 	mtx_init(&ap_boot_mtx, "ap boot", MTX_SPIN);
 
-	boot_cpu_id = PCPU_GET(cpuid);
-	KASSERT(boot_cpu_id == hwrpb->rpb_primary_cpu_id,
-	    ("mp_start() called on non-primary CPU"));
-	all_cpus = 1 << boot_cpu_id;
 	for (i = 0; i < hwrpb->rpb_pcs_cnt; i++) {
 		struct pcs *pcsp;
 
Index: src/sys/i386/i386/mp_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/i386/mp_machdep.c,v
retrieving revision 1.160
diff -u -r1.160 mp_machdep.c
--- src/sys/i386/i386/mp_machdep.c	2001/07/12 06:32:50	1.160
+++ src/sys/i386/i386/mp_machdep.c	2001/07/22 21:45:04
@@ -406,6 +406,12 @@
 int
 cpu_mp_probe(void)
 {
+	/*
+	 * Record BSP in CPU map
+	 * This is done here so that MBUF init code works correctly.
+	 */
+	all_cpus = 1;
+
 	return (mp_capable);
 }
 
@@ -1928,9 +1934,6 @@
 	outb(CMOS_REG, BIOS_RESET);
 	mpbiosreason = inb(CMOS_DATA);
 #endif
-
-	/* record BSP in CPU map */
-	all_cpus = 1;
 
 	/* set up temporary P==V mapping for AP boot */
 	/* XXX this is a hack, we should boot the AP on its own stack/PTD */
Index: src/sys/ia64/ia64/mp_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/ia64/ia64/mp_machdep.c,v
retrieving revision 1.17
diff -u -r1.17 mp_machdep.c
--- src/sys/ia64/ia64/mp_machdep.c	2001/05/15 23:22:24	1.17
+++ src/sys/ia64/ia64/mp_machdep.c	2001/07/22 21:45:04
@@ -71,6 +71,7 @@
 int
 cpu_mp_probe()
 {
+	all_cpus = 1;	/* Needed for MB init code */
 	return (0);
 }
 
Index: src/sys/kern/subr_mbuf.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/subr_mbuf.c,v
retrieving revision 1.3
diff -u -r1.3 subr_mbuf.c
--- src/sys/kern/subr_mbuf.c	2001/07/17 15:51:12	1.3
+++ src/sys/kern/subr_mbuf.c	2001/07/22 21:45:04
@@ -48,7 +48,12 @@
 /*
  * Maximum number of PCPU containers. If you know what you're doing you could
  * explicitly define MBALLOC_NCPU to be exactly the number of CPUs on your
- * system during compilation, and thus prevent kernel structure bloats.
+ * system during compilation, and thus prevent kernel structure bloat.
+ *
+ * SMP and non-SMP kernels clearly have a different number of possible cpus,
+ * but because we cannot assume a dense array of CPUs, we always allocate
+ * and traverse PCPU containers up to NCPU amount and merely check for
+ * CPU availability.
  */
 #ifdef	MBALLOC_NCPU
 #define	NCPU	MBALLOC_NCPU
@@ -57,12 +62,18 @@
 #endif
 
 /*
- * SMP and non-SMP kernels clearly have a different number of possible cpus.
+ * Macros allowing us to determine whether or not a given CPU's container
+ * should be configured during mb_init().
+ * XXX: Eventually we may want to provide hooks for CPU spinon/spinoff that
+ *      will allow us to configure the containers on spinon/spinoff. As it
+ *      stands, booting with CPU x disactivated and activating CPU x only
+ *      after bootup will lead to disaster and CPU x's container will be
+ *      uninitialized.
  */
 #ifdef	SMP
-#define	NCPU_PRESENT	mp_ncpus
+#define	CPU_ABSENT(x)	((all_cpus & (1 << x)) == 0)
 #else
-#define	NCPU_PRESENT	1
+#define	CPU_ABSENT(x)	0
 #endif
 
 /*
@@ -388,7 +399,10 @@
 	/*
 	 * Allocate and initialize PCPU containers.
 	 */
-	for (i = 0; i < NCPU_PRESENT; i++) {
+	for (i = 0; i < NCPU; i++) {
+		if (CPU_ABSENT(i))
+			continue;
+
 		mb_list_mbuf.ml_cntlst[i] = malloc(sizeof(struct mb_pcpu_list),
 		    M_MBUF, M_NOWAIT);
 		mb_list_clust.ml_cntlst[i] = malloc(sizeof(struct mb_pcpu_list),
@@ -401,6 +415,7 @@
 		mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_lock =
 		    mb_list_clust.ml_cntlst[i]->mb_cont.mc_lock = &mbuf_pcpu[i];
 
+		mb_statpcpu[i].mb_active = 1;
 		mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_numowner =
 		    mb_list_clust.ml_cntlst[i]->mb_cont.mc_numowner = i;
 		mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_starved =
@@ -626,7 +641,9 @@
 	 * Cycle all the PCPU containers. Increment starved counts if found
 	 * empty.
 	 */
-	for (i = 0; i < NCPU_PRESENT; i++) {
+	for (i = 0; i < NCPU; i++) {
+		if (CPU_ABSENT(i))
+			continue;
 		cnt_lst = MB_GET_PCPU_LIST_NUM(mb_list, i);
 		MB_LOCK_CONT(cnt_lst);
 
Index: src/sys/powerpc/powerpc/mp_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/powerpc/powerpc/mp_machdep.c,v
retrieving revision 1.8
diff -u -r1.8 mp_machdep.c
--- src/sys/powerpc/powerpc/mp_machdep.c	2001/06/16 07:14:07	1.8
+++ src/sys/powerpc/powerpc/mp_machdep.c	2001/07/22 21:45:04
@@ -51,6 +51,7 @@
 int
 cpu_mp_probe(void)
 {
+	all_cpus = 1;	/* needed for MB init code */
 	return 0;
 }
 
Index: src/sys/sys/mbuf.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/mbuf.h,v
retrieving revision 1.82
diff -u -r1.82 mbuf.h
--- src/sys/sys/mbuf.h	2001/06/22 06:35:19	1.82
+++ src/sys/sys/mbuf.h	2001/07/22 21:45:04
@@ -216,6 +216,7 @@
 	u_long	mb_mbpgs;
 	u_long	mb_clfree;
 	u_long	mb_clpgs;
+	short	mb_active;
 };
 
 /*
Index: src/usr.bin/netstat/mbuf.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/netstat/mbuf.c,v
retrieving revision 1.26
diff -u -r1.26 mbuf.c
--- src/usr.bin/netstat/mbuf.c	2001/06/23 17:04:17	1.26
+++ src/usr.bin/netstat/mbuf.c	2001/07/22 21:45:47
@@ -102,7 +102,7 @@
     u_long mblimaddr, u_long cllimaddr, u_long cpusaddr, u_long pgsaddr,
     u_long mbpaddr)
 {
-	int i, nmbufs, nmbclusters, ncpu, page_size, num_objs;
+	int i, nmbufs, nmbclusters, page_size, num_objs;
 	u_int mbuf_limit, clust_limit;
 	u_long totspace, totnum, totfree;
 	size_t mlen;
@@ -180,8 +180,6 @@
 			goto err;
 		if (kread(cllimaddr, (char *)&clust_limit, sizeof(u_int)))
 			goto err;
-		if (kread(cpusaddr, (char *)&ncpu, sizeof(int)))
-			goto err;
 		if (kread(pgsaddr, (char *)&page_size, sizeof(int)))
 			goto err;
 	} else {
@@ -228,12 +226,6 @@
 			goto err;
 		}
 		mlen = sizeof(int);
-		if (sysctlbyname("kern.smp.cpus", &ncpu, &mlen, NULL, 0) < 0 &&
-		    sysctlbyname("hw.ncpu", &ncpu, &mlen, NULL, 0) < 0) {
-			warn("sysctl: retrieving number of cpus");
-			goto err;
-		}
-		mlen = sizeof(int);
 		if (sysctlbyname("hw.pagesize", &page_size, &mlen, NULL, 0)
 		    < 0) {
 			warn("sysctl: retrieving hw.pagesize");
@@ -259,7 +251,9 @@
 	totnum = mbpstat[GENLST]->mb_mbpgs * MBPERPG;
 	totfree = mbpstat[GENLST]->mb_mbfree;
 	totspace = mbpstat[GENLST]->mb_mbpgs * page_size;
-	for (i = 0; i < ncpu; i++) {
+	for (i = 0; i < (num_objs - 1); i++) {
+		if (mbpstat[i]->mb_active == 0)
+			continue;
 		printf("\tCPU #%d list:\t%lu/%lu (in use/in pool)\n", i,
 		    (mbpstat[i]->mb_mbpgs * MBPERPG - mbpstat[i]->mb_mbfree),
 		    (mbpstat[i]->mb_mbpgs * MBPERPG));
@@ -281,7 +275,9 @@
 	totnum = mbpstat[GENLST]->mb_clpgs * CLPERPG;
 	totfree = mbpstat[GENLST]->mb_clfree;
 	totspace = mbpstat[GENLST]->mb_clpgs * page_size;
-	for (i = 0; i < ncpu; i++) {
+	for (i = 0; i < (num_objs - 1); i++) {
+		if (mbpstat[i]->mb_active == 0)
+			continue;
 		printf("\tCPU #%d list:\t%lu/%lu (in use/in pool)\n", i,
 		    (mbpstat[i]->mb_clpgs * CLPERPG - mbpstat[i]->mb_clfree),
 		    (mbpstat[i]->mb_clpgs * CLPERPG));
Index: src/usr.bin/systat/mbufs.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/systat/mbufs.c,v
retrieving revision 1.13
diff -u -r1.13 mbufs.c
--- src/usr.bin/systat/mbufs.c	2001/06/23 17:03:27	1.13
+++ src/usr.bin/systat/mbufs.c	2001/07/22 21:45:59
@@ -50,7 +50,7 @@
 #include "extern.h"
 
 static struct mbpstat **mbpstat;
-static int num_objs, ncpu;
+static int num_objs;
 #define	GENLST	(num_objs - 1)
 
 /* XXX: mbtypes stats temporarily disabled. */
@@ -150,8 +150,11 @@
 	 * Print total number of free mbufs.
 	 */
 	totfree = mbpstat[GENLST]->mb_mbfree; 
-	for (i = 0; i < ncpu; i++)
+	for (i = 0; i < (num_objs - 1); i++) {
+		if (mbpstat[i]->mb_active == 0)
+			continue;
 		totfree += mbpstat[i]->mb_mbfree;
+	}
 	j = 0;	/* XXX */
 	if (totfree > 0) {
 		mvwprintw(wnd, 1+j, 0, "%-10.10s", "free");
@@ -189,12 +192,6 @@
 	}
 	nmbtypes = mbtypeslen / sizeof(*m_mbtypes);
 #endif
-	len = sizeof(int);
-	if (sysctlbyname("kern.smp.cpus", &ncpu, &len, NULL, 0) < 0 &&
-	    sysctlbyname("hw.ncpu", &ncpu, &len, NULL, 0) < 0) {
-		error("sysctl getting number of cpus");
-		return 0;
-	}
 	if (sysctlbyname("kern.ipc.mb_statpcpu", NULL, &len, NULL, 0) < 0) {
 		error("sysctl getting mbpstat total size failed");
 		return 0;