- Re-implement lock profiling in such a way that it no longer breaks

   the ABI when enabled.  There is no longer an embedded lock_profile_object
   in each lock.  Instead a list of lock_profile_objects is kept per-thread
   for each lock it may own.  The cnt_hold statistic is now always 0 to
   facilitate this.
 - Support shared locking by tracking individual lock instances and
   statistics in the per-thread per-instance lock_profile_object.
 - Make the lock profiling hash table a per-cpu singly linked list with a
   per-cpu static lock_prof allocator.  This removes the need for an array
   of spinlocks and reduces cache contention between cores.
 - Use a seperate hash for spinlocks and other locks so that only a
   critical_enter() is required and not a spinlock_enter() to modify the
   per-cpu tables.
 - Count time spent spinning in the lock statistics.
 - Remove the LOCK_PROFILE_SHARED option as it is always supported now.
 - Specifically drop and release the scheduler locks in both schedulers
   since we track owners now.

In collaboration with:	Kip Macy
Sponsored by:	Nokia

1 files changed, 434 insertions, 222 deletions

diff --git a/sys/kern/subr_lock.c b/sys/kern/subr_lock.c
index ebb3c35..19f3639 100644
--- a/sys/kern/subr_lock.c
+++ b/sys/kern/subr_lock.c
@@ -40,17 +40,24 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/kernel.h>
 #include <sys/ktr.h>
 #include <sys/linker_set.h>
 #include <sys/lock.h>
+#include <sys/lock_profile.h>
+#include <sys/malloc.h>
+#include <sys/pcpu.h>
+#include <sys/proc.h>
 #include <sys/sbuf.h>
+#include <sys/smp.h>
 #include <sys/sysctl.h>
-#include <sys/lock_profile.h>
 
 #ifdef DDB
 #include <ddb/ddb.h>
 #endif
 
+#include <machine/cpufunc.h>
+
 CTASSERT(LOCK_CLASS_MAX == 15);
 
 struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = {
@@ -62,136 +69,6 @@ struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = {
 	&lock_class_lockmgr,
 };
 
-#ifdef LOCK_PROFILING
-#include <machine/cpufunc.h>
-
-SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging");
-SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, "lock profiling");
-int lock_prof_enable = 0;
-SYSCTL_INT(_debug_lock_prof, OID_AUTO, enable, CTLFLAG_RW,
-    &lock_prof_enable, 0, "Enable lock profiling");
-
-/*
- * lprof_buf is a static pool of profiling records to avoid possible
- * reentrance of the memory allocation functions.
- *
- * Note: NUM_LPROF_BUFFERS must be smaller than LPROF_HASH_SIZE.
- */
-struct lock_prof lprof_buf[LPROF_HASH_SIZE];
-static int allocated_lprof_buf;
-struct mtx lprof_locks[LPROF_LOCK_SIZE];
-
-
-/* SWAG: sbuf size = avg stat. line size * number of locks */
-#define LPROF_SBUF_SIZE		256 * 400
-
-static int lock_prof_acquisitions;
-SYSCTL_INT(_debug_lock_prof, OID_AUTO, acquisitions, CTLFLAG_RD,
-    &lock_prof_acquisitions, 0, "Number of lock acquistions recorded");
-static int lock_prof_records;
-SYSCTL_INT(_debug_lock_prof, OID_AUTO, records, CTLFLAG_RD,
-    &lock_prof_records, 0, "Number of profiling records");
-static int lock_prof_maxrecords = LPROF_HASH_SIZE;
-SYSCTL_INT(_debug_lock_prof, OID_AUTO, maxrecords, CTLFLAG_RD,
-    &lock_prof_maxrecords, 0, "Maximum number of profiling records");
-static int lock_prof_rejected;
-SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD,
-    &lock_prof_rejected, 0, "Number of rejected profiling records");
-static int lock_prof_hashsize = LPROF_HASH_SIZE;
-SYSCTL_INT(_debug_lock_prof, OID_AUTO, hashsize, CTLFLAG_RD,
-    &lock_prof_hashsize, 0, "Hash size");
-static int lock_prof_collisions = 0;
-SYSCTL_INT(_debug_lock_prof, OID_AUTO, collisions, CTLFLAG_RD,
-    &lock_prof_collisions, 0, "Number of hash collisions");
-
-#ifndef USE_CPU_NANOSECONDS
-u_int64_t
-nanoseconds(void)
-{
-	struct timespec tv;
-
-	nanotime(&tv);
-	return (tv.tv_sec * (u_int64_t)1000000000 + tv.tv_nsec);
-}
-#endif
-
-static int
-dump_lock_prof_stats(SYSCTL_HANDLER_ARGS)
-{
-        struct sbuf *sb;
-        int error, i;
-        static int multiplier = 1;
-        const char *p;
-
-        if (allocated_lprof_buf == 0)
-                return (SYSCTL_OUT(req, "No locking recorded",
-                    sizeof("No locking recorded")));
-
-retry_sbufops:
-        sb = sbuf_new(NULL, NULL, LPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
-        sbuf_printf(sb, "\n%6s %12s %12s %11s %5s %5s %12s %12s %s\n",
-            "max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name");
-        for (i = 0; i < LPROF_HASH_SIZE; ++i) {
-                if (lprof_buf[i].name == NULL)
-                        continue;
-                for (p = lprof_buf[i].file;
-                        p != NULL && strncmp(p, "../", 3) == 0; p += 3)
-                                /* nothing */ ;
-                sbuf_printf(sb, "%6ju %12ju %12ju %11ju %5ju %5ju %12ju %12ju %s:%d (%s:%s)\n",
-                    lprof_buf[i].cnt_max / 1000,
-                    lprof_buf[i].cnt_tot / 1000,
-                    lprof_buf[i].cnt_wait / 1000,
-                    lprof_buf[i].cnt_cur,
-                    lprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
-                        lprof_buf[i].cnt_tot / (lprof_buf[i].cnt_cur * 1000),
-                    lprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
-                        lprof_buf[i].cnt_wait / (lprof_buf[i].cnt_cur * 1000),
-                    lprof_buf[i].cnt_contest_holding,
-                    lprof_buf[i].cnt_contest_locking,
-                    p, lprof_buf[i].line, 
-			    lprof_buf[i].type,
-			    lprof_buf[i].name);
-                if (sbuf_overflowed(sb)) {
-                        sbuf_delete(sb);
-                        multiplier++;
-                        goto retry_sbufops;
-                }
-        }
-
-        sbuf_finish(sb);
-        error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
-        sbuf_delete(sb);
-        return (error);
-}
-static int
-reset_lock_prof_stats(SYSCTL_HANDLER_ARGS)
-{
-        int error, v;
-
-        if (allocated_lprof_buf == 0)
-                return (0);
-
-        v = 0;
-        error = sysctl_handle_int(oidp, &v, 0, req);
-        if (error)
-                return (error);
-        if (req->newptr == NULL)
-                return (error);
-        if (v == 0)
-                return (0);
-
-        bzero(lprof_buf, LPROF_HASH_SIZE*sizeof(*lprof_buf));
-        allocated_lprof_buf = 0;
-        return (0);
-}
-
-SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
-    NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics");
-
-SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
-    NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics");
-#endif
-
 void
 lock_init(struct lock_object *lock, struct lock_class *class, const char *name,
     const char *type, int flags)
@@ -216,7 +93,6 @@ lock_init(struct lock_object *lock, struct lock_class *class, const char *name,
 	lock->lo_flags |= flags | LO_INITIALIZED;
 	LOCK_LOG_INIT(lock, 0);
 	WITNESS_INIT(lock);
-	lock_profile_object_init(lock, class, name);
 }
 
 void
@@ -224,7 +100,6 @@ lock_destroy(struct lock_object *lock)
 {
 
 	KASSERT(lock_initalized(lock), ("lock %p is not initialized", lock));
-	lock_profile_object_destroy(lock);
 	WITNESS_DESTROY(lock);
 	LOCK_LOG_DESTROY(lock, 0);
 	lock->lo_flags &= ~LO_INITIALIZED;
@@ -253,17 +128,376 @@ DB_SHOW_COMMAND(lock, db_show_lock)
 #endif
 
 #ifdef LOCK_PROFILING
-void _lock_profile_obtain_lock_success(struct lock_object *lo, int contested, uint64_t waittime, const char *file, int line)
+
+/*
+ * One object per-thread for each lock the thread owns.  Tracks individual
+ * lock instances.
+ */
+struct lock_profile_object {
+	LIST_ENTRY(lock_profile_object) lpo_link;
+	struct lock_object *lpo_obj;
+	const char	*lpo_file;
+	int		lpo_line;
+	uint16_t	lpo_ref;
+	uint16_t	lpo_cnt;
+	u_int64_t	lpo_acqtime;
+	u_int64_t	lpo_waittime;
+	u_int		lpo_contest_locking;
+};
+
+/*
+ * One lock_prof for each (file, line, lock object) triple.
+ */
+struct lock_prof {
+	SLIST_ENTRY(lock_prof) link;
+	const char	*file;
+	const char	*name;
+	int		line;
+	int		ticks;
+	const char	*type;
+	uintmax_t	cnt_max;
+	uintmax_t	cnt_tot;
+	uintmax_t	cnt_wait;
+	uintmax_t	cnt_cur;
+	uintmax_t	cnt_contest_locking;
+};
+
+SLIST_HEAD(lphead, lock_prof);
+
+#define	LPROF_HASH_SIZE		4096
+#define	LPROF_HASH_MASK		(LPROF_HASH_SIZE - 1)
+#define	LPROF_CACHE_SIZE	4096
+
+/*
+ * Array of objects and profs for each type of object for each cpu.  Spinlocks
+ * are handled seperately because a thread may be preempted and acquire a
+ * spinlock while in the lock profiling code of a non-spinlock.  In this way
+ * we only need a critical section to protect the per-cpu lists.
+ */
+struct lock_prof_type {
+	struct lphead		lpt_lpalloc;
+	struct lpohead		lpt_lpoalloc;
+	struct lphead		lpt_hash[LPROF_HASH_SIZE];
+	struct lock_prof	lpt_prof[LPROF_CACHE_SIZE];
+	struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE];
+};
+
+struct lock_prof_cpu {
+	struct lock_prof_type	lpc_types[2]; /* One for spin one for other. */
+};
+
+struct lock_prof_cpu *lp_cpu[MAXCPU];
+
+int lock_prof_enable = 0;
+
+/* SWAG: sbuf size = avg stat. line size * number of locks */
+#define LPROF_SBUF_SIZE		256 * 400
+
+static int lock_prof_rejected;
+static int lock_prof_skipspin;
+static int lock_prof_skipcount;
+
+#ifndef USE_CPU_NANOSECONDS
+u_int64_t
+nanoseconds(void)
 {
-        struct lock_profile_object *l = &lo->lo_profile_obj;
+	struct bintime bt;
+	u_int64_t ns;
+
+	binuptime(&bt);
+	/* From bintime2timespec */
+	ns = bt.sec * (u_int64_t)1000000000;
+	ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32;
+	return (ns);
+}
+#endif
 
-	lo->lo_profile_obj.lpo_contest_holding = 0;
-	
-	if (contested)
-		lo->lo_profile_obj.lpo_contest_locking++;		
+static void
+lock_prof_init_type(struct lock_prof_type *type)
+{
+	int i;
+
+	SLIST_INIT(&type->lpt_lpalloc);
+	LIST_INIT(&type->lpt_lpoalloc);
+	for (i = 0; i < LPROF_CACHE_SIZE; i++) {
+		SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i],
+		    link);
+		LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i],
+		    lpo_link);
+	}
+}
+
+static void
+lock_prof_init(void *arg)
+{
+	int cpu;
+
+	for (cpu = 0; cpu <= mp_maxid; cpu++) {
+		lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF,
+		    M_WAITOK | M_ZERO);
+		lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]);
+		lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]);
+	}
+}
+SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL);
+
+static void
+lock_prof_reset(void)
+{
+	struct lock_prof_cpu *lpc;
+	int enabled, i, cpu;
+
+	enabled = lock_prof_enable;
+	lock_prof_enable = 0;
+	for (cpu = 0; cpu <= mp_maxid; cpu++) {
+		lpc = lp_cpu[cpu];
+		for (i = 0; i < LPROF_CACHE_SIZE; i++) {
+			LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link);
+			LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link);
+		}
+		bzero(lpc, sizeof(*lpc));
+		lock_prof_init_type(&lpc->lpc_types[0]);
+		lock_prof_init_type(&lpc->lpc_types[1]);
+	}
+	lock_prof_enable = enabled;
+}
+
+static void
+lock_prof_output(struct lock_prof *lp, struct sbuf *sb)
+{
+	const char *p;
+
+	for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3);
+	sbuf_printf(sb,
+	    "%6ju %12ju %12ju %11ju %5ju %5ju %12ju %12ju %s:%d (%s:%s)\n",
+	    lp->cnt_max / 1000, lp->cnt_tot / 1000,
+	    lp->cnt_wait / 1000, lp->cnt_cur,
+	    lp->cnt_cur == 0 ? (uintmax_t)0 :
+	    lp->cnt_tot / (lp->cnt_cur * 1000),
+	    lp->cnt_cur == 0 ? (uintmax_t)0 :
+	    lp->cnt_wait / (lp->cnt_cur * 1000),
+	    (uintmax_t)0, lp->cnt_contest_locking,
+	    p, lp->line, lp->type, lp->name);
+}
+
+static void
+lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash,
+    int spin, int t)
+{
+	struct lock_prof_type *type;
+	struct lock_prof *l;
+	int cpu;
+
+	dst->file = match->file;
+	dst->line = match->line;
+	dst->type = match->type;
+	dst->name = match->name;
+
+	for (cpu = 0; cpu <= mp_maxid; cpu++) {
+		if (lp_cpu[cpu] == NULL)
+			continue;
+		type = &lp_cpu[cpu]->lpc_types[spin];
+		SLIST_FOREACH(l, &type->lpt_hash[hash], link) {
+			if (l->ticks == t)
+				continue;
+			if (l->file != match->file || l->line != match->line ||
+			    l->name != match->name || l->type != match->type)
+				continue;
+			l->ticks = t;
+			if (l->cnt_max > dst->cnt_max)
+				dst->cnt_max = l->cnt_max;
+			dst->cnt_tot += l->cnt_tot;
+			dst->cnt_wait += l->cnt_wait;
+			dst->cnt_cur += l->cnt_cur;
+			dst->cnt_contest_locking += l->cnt_contest_locking;
+		}
+	}
 	
-	l->lpo_filename = file;
-	l->lpo_lineno = line;
+}
+
+static void
+lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin,
+    int t)
+{
+	struct lock_prof *l;
+	int i;
+
+	for (i = 0; i < LPROF_HASH_SIZE; ++i) {
+		SLIST_FOREACH(l, &type->lpt_hash[i], link) {
+			struct lock_prof lp = {};
+
+			if (l->ticks == t)
+				continue;
+			lock_prof_sum(l, &lp, i, spin, t);
+			lock_prof_output(&lp, sb);
+			if (sbuf_overflowed(sb))
+				return;
+		}
+	}
+}
+
+static int
+dump_lock_prof_stats(SYSCTL_HANDLER_ARGS)
+{
+	static int multiplier = 1;
+	struct sbuf *sb;
+	int error, cpu, t;
+
+retry_sbufops:
+	sb = sbuf_new(NULL, NULL, LPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
+	sbuf_printf(sb, "\n%6s %12s %12s %11s %5s %5s %12s %12s %s\n",
+	    "max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name");
+	t = ticks;
+	for (cpu = 0; cpu <= mp_maxid; cpu++) {
+		if (lp_cpu[cpu] == NULL)
+			continue;
+		lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t);
+		lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t);
+		if (sbuf_overflowed(sb)) {
+			sbuf_delete(sb);
+			multiplier++;
+			goto retry_sbufops;
+		}
+	}
+
+	sbuf_finish(sb);
+	error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
+	sbuf_delete(sb);
+	return (error);
+}
+
+static int
+enable_lock_prof(SYSCTL_HANDLER_ARGS)
+{
+	int error, v;
+
+	v = lock_prof_enable;
+	error = sysctl_handle_int(oidp, &v, v, req);
+	if (error)
+		return (error);
+	if (req->newptr == NULL)
+		return (error);
+	if (v == lock_prof_enable)
+		return (0);
+	if (v == 1)
+		lock_prof_reset();
+	lock_prof_enable = !!v;
+
+	return (0);
+}
+
+static int
+reset_lock_prof_stats(SYSCTL_HANDLER_ARGS)
+{
+	int error, v;
+
+	v = 0;
+	error = sysctl_handle_int(oidp, &v, 0, req);
+	if (error)
+		return (error);
+	if (req->newptr == NULL)
+		return (error);
+	if (v == 0)
+		return (0);
+	lock_prof_reset();
+
+	return (0);
+}
+
+static struct lock_prof *
+lock_profile_lookup(struct lock_object *lo, int spin, const char *file,
+    int line)
+{
+	const char *unknown = "(unknown)";
+	struct lock_prof_type *type;
+	struct lock_prof *lp;
+	struct lphead *head;
+	const char *p;
+	u_int hash;
+
+	p = file;
+	if (p == NULL || *p == '\0')
+		p = unknown;
+	hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line;
+	hash &= LPROF_HASH_MASK;
+	type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
+	head = &type->lpt_hash[hash];
+	SLIST_FOREACH(lp, head, link) {
+		if (lp->line == line && lp->file == p &&
+		    lp->name == lo->lo_name)
+			return (lp);
+
+	}
+	lp = SLIST_FIRST(&type->lpt_lpalloc);
+	if (lp == NULL) {
+		lock_prof_rejected++;
+		return (lp);
+	}
+	SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link);
+	lp->file = p;
+	lp->line = line;
+	lp->type = lo->lo_type;
+	lp->name = lo->lo_name;
+	SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link);
+	return (lp);
+}
+
+static struct lock_profile_object *
+lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file,
+    int line)
+{
+	struct lock_profile_object *l;
+	struct lock_prof_type *type;
+	struct lpohead *head;
+
+	head = &curthread->td_lprof[spin];
+	LIST_FOREACH(l, head, lpo_link)
+		if (l->lpo_obj == lo && l->lpo_file == file &&
+		    l->lpo_line == line)
+			return (l);
+	critical_enter();
+	type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
+	l = LIST_FIRST(&type->lpt_lpoalloc);
+	if (l == NULL) {
+		lock_prof_rejected++;
+		critical_exit();
+		return (NULL);
+	}
+	LIST_REMOVE(l, lpo_link);
+	critical_exit();
+	l->lpo_obj = lo;
+	l->lpo_file = file;
+	l->lpo_line = line;
+	l->lpo_cnt = 0;
+	LIST_INSERT_HEAD(head, l, lpo_link);
+
+	return (l);
+}
+
+void
+lock_profile_obtain_lock_success(struct lock_object *lo, int contested,
+    uint64_t waittime, const char *file, int line)
+{
+	static int lock_prof_count;
+	struct lock_profile_object *l;
+	int spin;
+
+	/* don't reset the timer when/if recursing */
+	if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE))
+		return;
+	if (lock_prof_skipcount &&
+	    (++lock_prof_count % lock_prof_skipcount) == 0)
+		return;
+	spin = LOCK_CLASS(lo) == &lock_class_mtx_spin;
+	if (spin && lock_prof_skipspin == 1)
+		return;
+	l = lock_profile_object_lookup(lo, spin, file, line);
+	if (l == NULL)
+		return;
+	l->lpo_cnt++;
+	if (++l->lpo_ref > 1)
+		return;
+	l->lpo_contest_locking = contested;
 	l->lpo_acqtime = nanoseconds(); 
 	if (waittime && (l->lpo_acqtime > waittime))
 		l->lpo_waittime = l->lpo_acqtime - waittime;
@@ -271,87 +505,65 @@ void _lock_profile_obtain_lock_success(struct lock_object *lo, int contested, ui
 		l->lpo_waittime = 0;
 }
 
-void _lock_profile_release_lock(struct lock_object *lo)
+void
+lock_profile_release_lock(struct lock_object *lo)
 {
-        struct lock_profile_object *l = &lo->lo_profile_obj;
-
-        if (l->lpo_acqtime) {
-                const char *unknown = "(unknown)";
-                u_int64_t acqtime, now, waittime;
-                struct lock_prof *mpp;
-                u_int hash;
-                const char *p = l->lpo_filename;
-                int collision = 0;
-
-                now = nanoseconds();
-                acqtime = l->lpo_acqtime;
-                waittime = l->lpo_waittime;
-                if (now <= acqtime)
-                        return;
-                if (p == NULL || *p == '\0')
-                        p = unknown;
-                hash = (l->lpo_namehash * 31 * 31 + (uintptr_t)p * 31 + l->lpo_lineno) & LPROF_HASH_MASK;
-                mpp = &lprof_buf[hash];
-                while (mpp->name != NULL) {
-                        if (mpp->line == l->lpo_lineno &&
-                          mpp->file == p &&
-                          mpp->namehash == l->lpo_namehash)
-                                break;
-                        /* If the lprof_hash entry is allocated to someone 
-			 * else, try the next one 
-			 */
-                        collision = 1;
-                        hash = (hash + 1) & LPROF_HASH_MASK;
-                        mpp = &lprof_buf[hash];
-                }
-                if (mpp->name == NULL) {
-                        int buf;
-
-                        buf = atomic_fetchadd_int(&allocated_lprof_buf, 1);
-                        /* Just exit if we cannot get a trace buffer */
-                        if (buf >= LPROF_HASH_SIZE) {
-                                ++lock_prof_rejected;
-                                return;
-                        }
-			mpp->file = p;
-			mpp->line = l->lpo_lineno;
-			mpp->namehash = l->lpo_namehash;
-			mpp->type = l->lpo_type;
-			mpp->name = lo->lo_name;
-
-			if (collision)
-				++lock_prof_collisions;
-			
-                        /* 
-			 * We might have raced someone else but who cares, 
-			 * they'll try again next time 
-			 */
-                        ++lock_prof_records;
-                }
-                LPROF_LOCK(hash);
-                /*
-                 * Record if the lock has been held longer now than ever
-                 * before.
-                 */
-                if (now - acqtime > mpp->cnt_max)
-                        mpp->cnt_max = now - acqtime;
-                mpp->cnt_tot += now - acqtime;
-                mpp->cnt_wait += waittime;
-                mpp->cnt_cur++;
-                /*
-                 * There's a small race, really we should cmpxchg
-                 * 0 with the current value, but that would bill
-                 * the contention to the wrong lock instance if
-                 * it followed this also.
-                 */
-                mpp->cnt_contest_holding += l->lpo_contest_holding;
-                mpp->cnt_contest_locking += l->lpo_contest_locking;
-                LPROF_UNLOCK(hash);
-
-        }
-        l->lpo_acqtime = 0;
-        l->lpo_waittime = 0;
-        l->lpo_contest_locking = 0;
-        l->lpo_contest_holding = 0;
+	struct lock_profile_object *l;
+	struct lock_prof_type *type;
+	struct lock_prof *lp;
+	u_int64_t holdtime;
+	struct lpohead *head;
+	int spin;
+
+	if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE))
+		return;
+	spin = LOCK_CLASS(lo) == &lock_class_mtx_spin;
+	head = &curthread->td_lprof[spin];
+	critical_enter();
+	LIST_FOREACH(l, head, lpo_link)
+		if (l->lpo_obj == lo)
+			break;
+	if (l == NULL)
+		goto out;
+	if (--l->lpo_ref > 0)
+		goto out;
+	lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line);
+	if (lp == NULL)
+		goto release;
+	holdtime = nanoseconds() - l->lpo_acqtime;
+	if (holdtime < 0)
+		goto release;
+	/*
+	 * Record if the lock has been held longer now than ever
+	 * before.
+	 */
+	if (holdtime > lp->cnt_max)
+		lp->cnt_max = holdtime;
+	lp->cnt_tot += holdtime;
+	lp->cnt_wait += l->lpo_waittime;
+	lp->cnt_contest_locking += l->lpo_contest_locking;
+	lp->cnt_cur += l->lpo_cnt;
+release:
+	LIST_REMOVE(l, lpo_link);
+	type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
+	LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link);
+out:
+	critical_exit();
 }
+
+SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging");
+SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, "lock profiling");
+SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW,
+    &lock_prof_skipspin, 0, "Skip profiling on spinlocks.");
+SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW,
+    &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions.");
+SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD,
+    &lock_prof_rejected, 0, "Number of rejected profiling records");
+SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
+    NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics");
+SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
+    NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics");
+SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW,
+    NULL, 0, enable_lock_prof, "I", "Enable lock profiling");
+
 #endif