sysctl kern.pool_debug=0 will disable POOL_DEBUG on the fly (still defaults

to on, if POOL_DEBUG is compiled in, so that boot-time pool corruption
can be found.  When the sysctl is turned off, performance is almost as
as good as compiling with POOL_DEBUG compiled out.  Not all pool page
headers can be purged of the magic checks.
performance tests by henning
ok ariane kettenis mikeb

3 files changed, 55 insertions, 27 deletions

diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index a2536b7a297..2ac85792d08 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sysctl.c,v 1.199 2011/04/02 16:47:17 beck Exp $	*/
+/*	$OpenBSD: kern_sysctl.c,v 1.200 2011/04/04 11:13:55 deraadt Exp $	*/
 /*	$NetBSD: kern_sysctl.c,v 1.17 1996/05/20 17:49:05 mrg Exp $	*/
 
 /*-
@@ -270,6 +270,7 @@ kern_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 	extern int cryptodevallowsoft;
 #endif
 	extern int maxlocksperuid;
+	extern int pool_debug;
 
 	/* all sysctl names at this level are terminal except a ton of them */
 	if (namelen != 1) {
@@ -591,6 +592,15 @@ kern_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 		return sysctl_rdstruct(oldp, oldlenp, newp, &dev, sizeof(dev));
 	case KERN_NETLIVELOCKS:
 		return (sysctl_rdint(oldp, oldlenp, newp, mcllivelocks));
+	case KERN_POOL_DEBUG: {
+		int old_pool_debug = pool_debug;
+
+		error = sysctl_int(oldp, oldlenp, newp, newlen,
+		    &pool_debug);
+		if (error == 0 && pool_debug != old_pool_debug)
+			pool_reclaim_all();
+		return (error);
+	}
 	default:
 		return (EOPNOTSUPP);
 	}
diff --git a/sys/kern/subr_pool.c b/sys/kern/subr_pool.c
index c7d85ff0f23..345544b4f04 100644
--- a/sys/kern/subr_pool.c
+++ b/sys/kern/subr_pool.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_pool.c,v 1.100 2011/04/03 22:07:37 ariane Exp $	*/
+/*	$OpenBSD: subr_pool.c,v 1.101 2011/04/04 11:13:55 deraadt Exp $	*/
 /*	$NetBSD: subr_pool.c,v 1.61 2001/09/26 07:14:56 chs Exp $	*/
 
 /*-
@@ -42,7 +42,7 @@
 #include <sys/sysctl.h>
 
 #include <uvm/uvm.h>
-
+#include <dev/rndvar.h>
 
 /*
  * Pool resource management utility.
@@ -74,6 +74,7 @@ struct pool_item_header {
 	caddr_t			ph_page;	/* this page's address */
 	caddr_t			ph_colored;	/* page's colored address */
 	int			ph_pagesize;
+	int			ph_magic;
 };
 
 struct pool_item {
@@ -90,6 +91,12 @@ struct pool_item {
 #define	PI_MAGIC 0xdeafbeef
 #endif
 
+#ifdef POOL_DEBUG
+int	pool_debug = 1;
+#else
+int	pool_debug = 0;
+#endif
+
 #define	POOL_NEEDS_CATCHUP(pp)						\
 	((pp)->pr_nitems < (pp)->pr_minitems)
 
@@ -441,7 +448,8 @@ pool_alloc_item_header(struct pool *pp, caddr_t storage, int flags)
 	else
 		ph = pool_get(&phpool, (flags & ~(PR_WAITOK | PR_ZERO)) |
 		    PR_NOWAIT);
-
+	if (pool_debug)
+		ph->ph_magic = PI_MAGIC;
 	return (ph);
 }
 
@@ -611,13 +619,15 @@ startover:
 		    "page %p; item addr %p; offset 0x%x=0x%x",
 		    pp->pr_wchan, ph->ph_page, pi, 0, pi->pi_magic);
 #ifdef POOL_DEBUG
-	for (ip = (int *)pi, i = sizeof(*pi) / sizeof(int);
-	    i < pp->pr_size / sizeof(int); i++) {
-		if (ip[i] != PI_MAGIC) {
-			panic("pool_do_get(%s): free list modified: "
-			    "page %p; item addr %p; offset 0x%x=0x%x",
-			    pp->pr_wchan, ph->ph_page, pi,
-			    i * sizeof(int), ip[i]);
+	if (pool_debug && ph->ph_magic) {
+		for (ip = (int *)pi, i = sizeof(*pi) / sizeof(int);
+		    i < pp->pr_size / sizeof(int); i++) {
+			if (ip[i] != ph->ph_magic) {
+				panic("pool_do_get(%s): free list modified: "
+				    "page %p; item addr %p; offset 0x%x=0x%x",
+				    pp->pr_wchan, ph->ph_page, pi,
+				    i * sizeof(int), ip[i]);
+			}
 		}
 	}
 #endif /* POOL_DEBUG */
@@ -731,9 +741,11 @@ pool_do_put(struct pool *pp, void *v)
 #ifdef DIAGNOSTIC
 	pi->pi_magic = PI_MAGIC;
 #ifdef POOL_DEBUG
-	for (ip = (int *)pi, i = sizeof(*pi)/sizeof(int);
-	    i < pp->pr_size / sizeof(int); i++)
-		ip[i] = PI_MAGIC;
+	if (ph->ph_magic) {
+		for (ip = (int *)pi, i = sizeof(*pi)/sizeof(int);
+		    i < pp->pr_size / sizeof(int); i++)
+			ip[i] = ph->ph_magic;
+	}
 #endif /* POOL_DEBUG */
 #endif /* DIAGNOSTIC */
 
@@ -886,9 +898,11 @@ pool_prime_page(struct pool *pp, caddr_t storage, struct pool_item_header *ph)
 #ifdef DIAGNOSTIC
 		pi->pi_magic = PI_MAGIC;
 #ifdef POOL_DEBUG
-		for (ip = (int *)pi, i = sizeof(*pi)/sizeof(int);
-		    i < pp->pr_size / sizeof(int); i++)
-			ip[i] = PI_MAGIC;
+		if (ph->ph_magic) {
+			for (ip = (int *)pi, i = sizeof(*pi)/sizeof(int);
+			    i < pp->pr_size / sizeof(int); i++)
+				ip[i] = ph->ph_magic;
+		}
 #endif /* POOL_DEBUG */
 #endif /* DIAGNOSTIC */
 		cp = (caddr_t)(cp + pp->pr_size);
@@ -1273,14 +1287,16 @@ pool_chk_page(struct pool *pp, const char *label, struct pool_item_header *ph)
 			    0, pi->pi_magic);
 		}
 #ifdef POOL_DEBUG
-		for (ip = (int *)pi, i = sizeof(*pi) / sizeof(int);
-		    i < pp->pr_size / sizeof(int); i++) {
-			if (ip[i] != PI_MAGIC) {
-				printf("pool(%s): free list modified: "
-				    "page %p; item ordinal %d; addr %p "
-				    "(p %p); offset 0x%x=0x%x\n",
-				    pp->pr_wchan, ph->ph_page, n, pi,
-				    page, i * sizeof(int), ip[i]);
+		if (pool_debug && ph->ph_magic) {
+			for (ip = (int *)pi, i = sizeof(*pi) / sizeof(int);
+			    i < pp->pr_size / sizeof(int); i++) {
+				if (ip[i] != ph->ph_magic) {
+					printf("pool(%s): free list modified: "
+					    "page %p; item ordinal %d; addr %p "
+					    "(p %p); offset 0x%x=0x%x\n",
+					    pp->pr_wchan, ph->ph_page, n, pi,
+					    page, i * sizeof(int), ip[i]);
+				}
 			}
 		}
 
diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index 346b33a36b8..5de3000f636 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sysctl.h,v 1.109 2011/03/12 04:54:28 guenther Exp $	*/
+/*	$OpenBSD: sysctl.h,v 1.110 2011/04/04 11:13:53 deraadt Exp $	*/
 /*	$NetBSD: sysctl.h,v 1.16 1996/04/09 20:55:36 cgd Exp $	*/
 
 /*
@@ -188,7 +188,8 @@ struct ctlname {
 #define	KERN_RTHREADS		74	/* kernel rthreads support enabled */
 #define	KERN_CONSDEV		75	/* dev_t: console terminal device */
 #define	KERN_NETLIVELOCKS	76	/* int: number of network livelocks */
-#define	KERN_MAXID		77	/* number of valid kern ids */
+#define	KERN_POOL_DEBUG		77	/* int: enable pool_debug */
+#define	KERN_MAXID		78	/* number of valid kern ids */
 
 #define	CTL_KERN_NAMES { \
 	{ 0, 0 }, \
@@ -268,6 +269,7 @@ struct ctlname {
 	{ "rthreads", CTLTYPE_INT }, \
 	{ "consdev", CTLTYPE_STRUCT }, \
 	{ "netlivelocks", CTLTYPE_INT }, \
+	{ "pool_debug", CTLTYPE_INT }, \
 }
 
 /*