1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28/*
29 * This module holds the global variables and functions used to maintain
30 * lock_object structures.
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD$");
35
36#include "opt_ddb.h"
37#include "opt_mprof.h"
38
39#include <sys/param.h>
40#include <sys/systm.h>
41#include <sys/kernel.h>
42#include <sys/ktr.h>
43#include <sys/lock.h>
44#include <sys/lock_profile.h>
45#include <sys/malloc.h>
46#include <sys/mutex.h>
47#include <sys/pcpu.h>
48#include <sys/proc.h>
49#include <sys/sbuf.h>
50#include <sys/sched.h>
51#include <sys/smp.h>
52#include <sys/sysctl.h>
53
54#ifdef DDB
55#include <ddb/ddb.h>
56#endif
57
58#include <machine/cpufunc.h>
59
60SDT_PROVIDER_DEFINE(lock);
61SDT_PROBE_DEFINE1(lock, , , starvation, "u_int");
62
63CTASSERT(LOCK_CLASS_MAX == 15);
64
65struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = {
66	&lock_class_mtx_spin,
67	&lock_class_mtx_sleep,
68	&lock_class_sx,
69	&lock_class_rm,
70	&lock_class_rm_sleepable,
71	&lock_class_rw,
72	&lock_class_lockmgr,
73};
74
75void
76lock_init(struct lock_object *lock, struct lock_class *class, const char *name,
77    const char *type, int flags)
78{
79	int i;
80
81	/* Check for double-init and zero object. */
82	KASSERT(flags & LO_NEW || !lock_initialized(lock),
83	    ("lock \"%s\" %p already initialized", name, lock));
84
85	/* Look up lock class to find its index. */
86	for (i = 0; i < LOCK_CLASS_MAX; i++)
87		if (lock_classes[i] == class) {
88			lock->lo_flags = i << LO_CLASSSHIFT;
89			break;
90		}
91	KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class));
92
93	/* Initialize the lock object. */
94	lock->lo_name = name;
95	lock->lo_flags |= flags | LO_INITIALIZED;
96	LOCK_LOG_INIT(lock, 0);
97	WITNESS_INIT(lock, (type != NULL) ? type : name);
98}
99
100void
101lock_destroy(struct lock_object *lock)
102{
103
104	KASSERT(lock_initialized(lock), ("lock %p is not initialized", lock));
105	WITNESS_DESTROY(lock);
106	LOCK_LOG_DESTROY(lock, 0);
107	lock->lo_flags &= ~LO_INITIALIZED;
108}
109
110static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging");
111static SYSCTL_NODE(_debug_lock, OID_AUTO, delay, CTLFLAG_RD, NULL,
112    "lock delay");
113
114static u_int __read_mostly starvation_limit = 131072;
115SYSCTL_INT(_debug_lock_delay, OID_AUTO, starvation_limit, CTLFLAG_RW,
116    &starvation_limit, 0, "");
117
118static u_int __read_mostly restrict_starvation = 0;
119SYSCTL_INT(_debug_lock_delay, OID_AUTO, restrict_starvation, CTLFLAG_RW,
120    &restrict_starvation, 0, "");
121
122void
123lock_delay(struct lock_delay_arg *la)
124{
125	struct lock_delay_config *lc = la->config;
126	u_int i;
127
128	la->delay <<= 1;
129	if (__predict_false(la->delay > lc->max))
130		la->delay = lc->max;
131
132	for (i = la->delay; i > 0; i--)
133		cpu_spinwait();
134
135	la->spin_cnt += la->delay;
136	if (__predict_false(la->spin_cnt > starvation_limit)) {
137		SDT_PROBE1(lock, , , starvation, la->delay);
138		if (restrict_starvation)
139			la->delay = lc->base;
140	}
141}
142
143static u_int
144lock_roundup_2(u_int val)
145{
146	u_int res;
147
148	for (res = 1; res <= val; res <<= 1)
149		continue;
150
151	return (res);
152}
153
154void
155lock_delay_default_init(struct lock_delay_config *lc)
156{
157
158	lc->base = 1;
159	lc->max = lock_roundup_2(mp_ncpus) * 256;
160	if (lc->max > 32678)
161		lc->max = 32678;
162}
163
164#ifdef DDB
165DB_SHOW_COMMAND(lock, db_show_lock)
166{
167	struct lock_object *lock;
168	struct lock_class *class;
169
170	if (!have_addr)
171		return;
172	lock = (struct lock_object *)addr;
173	if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) {
174		db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock));
175		return;
176	}
177	class = LOCK_CLASS(lock);
178	db_printf(" class: %s\n", class->lc_name);
179	db_printf(" name: %s\n", lock->lo_name);
180	class->lc_ddb_show(lock);
181}
182#endif
183
184#ifdef LOCK_PROFILING
185
186/*
187 * One object per-thread for each lock the thread owns.  Tracks individual
188 * lock instances.
189 */
190struct lock_profile_object {
191	LIST_ENTRY(lock_profile_object) lpo_link;
192	struct lock_object *lpo_obj;
193	const char	*lpo_file;
194	int		lpo_line;
195	uint16_t	lpo_ref;
196	uint16_t	lpo_cnt;
197	uint64_t	lpo_acqtime;
198	uint64_t	lpo_waittime;
199	u_int		lpo_contest_locking;
200};
201
202/*
203 * One lock_prof for each (file, line, lock object) triple.
204 */
205struct lock_prof {
206	SLIST_ENTRY(lock_prof) link;
207	struct lock_class *class;
208	const char	*file;
209	const char	*name;
210	int		line;
211	int		ticks;
212	uintmax_t	cnt_wait_max;
213	uintmax_t	cnt_max;
214	uintmax_t	cnt_tot;
215	uintmax_t	cnt_wait;
216	uintmax_t	cnt_cur;
217	uintmax_t	cnt_contest_locking;
218};
219
220SLIST_HEAD(lphead, lock_prof);
221
222#define	LPROF_HASH_SIZE		4096
223#define	LPROF_HASH_MASK		(LPROF_HASH_SIZE - 1)
224#define	LPROF_CACHE_SIZE	4096
225
226/*
227 * Array of objects and profs for each type of object for each cpu.  Spinlocks
228 * are handled separately because a thread may be preempted and acquire a
229 * spinlock while in the lock profiling code of a non-spinlock.  In this way
230 * we only need a critical section to protect the per-cpu lists.
231 */
232struct lock_prof_type {
233	struct lphead		lpt_lpalloc;
234	struct lpohead		lpt_lpoalloc;
235	struct lphead		lpt_hash[LPROF_HASH_SIZE];
236	struct lock_prof	lpt_prof[LPROF_CACHE_SIZE];
237	struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE];
238};
239
240struct lock_prof_cpu {
241	struct lock_prof_type	lpc_types[2]; /* One for spin one for other. */
242};
243
244struct lock_prof_cpu *lp_cpu[MAXCPU];
245
246volatile int __read_mostly lock_prof_enable;
247static volatile int lock_prof_resetting;
248
249#define LPROF_SBUF_SIZE		256
250
251static int lock_prof_rejected;
252static int lock_prof_skipspin;
253static int lock_prof_skipcount;
254
255#ifndef USE_CPU_NANOSECONDS
256uint64_t
257nanoseconds(void)
258{
259	struct bintime bt;
260	uint64_t ns;
261
262	binuptime(&bt);
263	/* From bintime2timespec */
264	ns = bt.sec * (uint64_t)1000000000;
265	ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32;
266	return (ns);
267}
268#endif
269
270static void
271lock_prof_init_type(struct lock_prof_type *type)
272{
273	int i;
274
275	SLIST_INIT(&type->lpt_lpalloc);
276	LIST_INIT(&type->lpt_lpoalloc);
277	for (i = 0; i < LPROF_CACHE_SIZE; i++) {
278		SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i],
279		    link);
280		LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i],
281		    lpo_link);
282	}
283}
284
285static void
286lock_prof_init(void *arg)
287{
288	int cpu;
289
290	for (cpu = 0; cpu <= mp_maxid; cpu++) {
291		lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF,
292		    M_WAITOK | M_ZERO);
293		lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]);
294		lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]);
295	}
296}
297SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL);
298
299static void
300lock_prof_reset_wait(void)
301{
302
303	/*
304	 * Spin relinquishing our cpu so that quiesce_all_cpus may
305	 * complete.
306	 */
307	while (lock_prof_resetting)
308		sched_relinquish(curthread);
309}
310
311static void
312lock_prof_reset(void)
313{
314	struct lock_prof_cpu *lpc;
315	int enabled, i, cpu;
316
317	/*
318	 * We not only race with acquiring and releasing locks but also
319	 * thread exit.  To be certain that threads exit without valid head
320	 * pointers they must see resetting set before enabled is cleared.
321	 * Otherwise a lock may not be removed from a per-thread list due
322	 * to disabled being set but not wait for reset() to remove it below.
323	 */
324	atomic_store_rel_int(&lock_prof_resetting, 1);
325	enabled = lock_prof_enable;
326	lock_prof_enable = 0;
327	quiesce_all_cpus("profreset", 0);
328	/*
329	 * Some objects may have migrated between CPUs.  Clear all links
330	 * before we zero the structures.  Some items may still be linked
331	 * into per-thread lists as well.
332	 */
333	for (cpu = 0; cpu <= mp_maxid; cpu++) {
334		lpc = lp_cpu[cpu];
335		for (i = 0; i < LPROF_CACHE_SIZE; i++) {
336			LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link);
337			LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link);
338		}
339	}
340	for (cpu = 0; cpu <= mp_maxid; cpu++) {
341		lpc = lp_cpu[cpu];
342		bzero(lpc, sizeof(*lpc));
343		lock_prof_init_type(&lpc->lpc_types[0]);
344		lock_prof_init_type(&lpc->lpc_types[1]);
345	}
346	atomic_store_rel_int(&lock_prof_resetting, 0);
347	lock_prof_enable = enabled;
348}
349
350static void
351lock_prof_output(struct lock_prof *lp, struct sbuf *sb)
352{
353	const char *p;
354
355	for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3);
356	sbuf_printf(sb,
357	    "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n",
358	    lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000,
359	    lp->cnt_wait / 1000, lp->cnt_cur,
360	    lp->cnt_cur == 0 ? (uintmax_t)0 :
361	    lp->cnt_tot / (lp->cnt_cur * 1000),
362	    lp->cnt_cur == 0 ? (uintmax_t)0 :
363	    lp->cnt_wait / (lp->cnt_cur * 1000),
364	    (uintmax_t)0, lp->cnt_contest_locking,
365	    p, lp->line, lp->class->lc_name, lp->name);
366}
367
368static void
369lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash,
370    int spin, int t)
371{
372	struct lock_prof_type *type;
373	struct lock_prof *l;
374	int cpu;
375
376	dst->file = match->file;
377	dst->line = match->line;
378	dst->class = match->class;
379	dst->name = match->name;
380
381	for (cpu = 0; cpu <= mp_maxid; cpu++) {
382		if (lp_cpu[cpu] == NULL)
383			continue;
384		type = &lp_cpu[cpu]->lpc_types[spin];
385		SLIST_FOREACH(l, &type->lpt_hash[hash], link) {
386			if (l->ticks == t)
387				continue;
388			if (l->file != match->file || l->line != match->line ||
389			    l->name != match->name)
390				continue;
391			l->ticks = t;
392			if (l->cnt_max > dst->cnt_max)
393				dst->cnt_max = l->cnt_max;
394			if (l->cnt_wait_max > dst->cnt_wait_max)
395				dst->cnt_wait_max = l->cnt_wait_max;
396			dst->cnt_tot += l->cnt_tot;
397			dst->cnt_wait += l->cnt_wait;
398			dst->cnt_cur += l->cnt_cur;
399			dst->cnt_contest_locking += l->cnt_contest_locking;
400		}
401	}
402
403}
404
405static void
406lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin,
407    int t)
408{
409	struct lock_prof *l;
410	int i;
411
412	for (i = 0; i < LPROF_HASH_SIZE; ++i) {
413		SLIST_FOREACH(l, &type->lpt_hash[i], link) {
414			struct lock_prof lp = {};
415
416			if (l->ticks == t)
417				continue;
418			lock_prof_sum(l, &lp, i, spin, t);
419			lock_prof_output(&lp, sb);
420		}
421	}
422}
423
424static int
425dump_lock_prof_stats(SYSCTL_HANDLER_ARGS)
426{
427	struct sbuf *sb;
428	int error, cpu, t;
429	int enabled;
430
431	error = sysctl_wire_old_buffer(req, 0);
432	if (error != 0)
433		return (error);
434	sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req);
435	sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n",
436	    "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name");
437	enabled = lock_prof_enable;
438	lock_prof_enable = 0;
439	quiesce_all_cpus("profstat", 0);
440	t = ticks;
441	for (cpu = 0; cpu <= mp_maxid; cpu++) {
442		if (lp_cpu[cpu] == NULL)
443			continue;
444		lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t);
445		lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t);
446	}
447	lock_prof_enable = enabled;
448
449	error = sbuf_finish(sb);
450	/* Output a trailing NUL. */
451	if (error == 0)
452		error = SYSCTL_OUT(req, "", 1);
453	sbuf_delete(sb);
454	return (error);
455}
456
457static int
458enable_lock_prof(SYSCTL_HANDLER_ARGS)
459{
460	int error, v;
461
462	v = lock_prof_enable;
463	error = sysctl_handle_int(oidp, &v, v, req);
464	if (error)
465		return (error);
466	if (req->newptr == NULL)
467		return (error);
468	if (v == lock_prof_enable)
469		return (0);
470	if (v == 1)
471		lock_prof_reset();
472	lock_prof_enable = !!v;
473
474	return (0);
475}
476
477static int
478reset_lock_prof_stats(SYSCTL_HANDLER_ARGS)
479{
480	int error, v;
481
482	v = 0;
483	error = sysctl_handle_int(oidp, &v, 0, req);
484	if (error)
485		return (error);
486	if (req->newptr == NULL)
487		return (error);
488	if (v == 0)
489		return (0);
490	lock_prof_reset();
491
492	return (0);
493}
494
495static struct lock_prof *
496lock_profile_lookup(struct lock_object *lo, int spin, const char *file,
497    int line)
498{
499	const char *unknown = "(unknown)";
500	struct lock_prof_type *type;
501	struct lock_prof *lp;
502	struct lphead *head;
503	const char *p;
504	u_int hash;
505
506	p = file;
507	if (p == NULL || *p == '\0')
508		p = unknown;
509	hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line;
510	hash &= LPROF_HASH_MASK;
511	type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
512	head = &type->lpt_hash[hash];
513	SLIST_FOREACH(lp, head, link) {
514		if (lp->line == line && lp->file == p &&
515		    lp->name == lo->lo_name)
516			return (lp);
517
518	}
519	lp = SLIST_FIRST(&type->lpt_lpalloc);
520	if (lp == NULL) {
521		lock_prof_rejected++;
522		return (lp);
523	}
524	SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link);
525	lp->file = p;
526	lp->line = line;
527	lp->class = LOCK_CLASS(lo);
528	lp->name = lo->lo_name;
529	SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link);
530	return (lp);
531}
532
533static struct lock_profile_object *
534lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file,
535    int line)
536{
537	struct lock_profile_object *l;
538	struct lock_prof_type *type;
539	struct lpohead *head;
540
541	head = &curthread->td_lprof[spin];
542	LIST_FOREACH(l, head, lpo_link)
543		if (l->lpo_obj == lo && l->lpo_file == file &&
544		    l->lpo_line == line)
545			return (l);
546	type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
547	l = LIST_FIRST(&type->lpt_lpoalloc);
548	if (l == NULL) {
549		lock_prof_rejected++;
550		return (NULL);
551	}
552	LIST_REMOVE(l, lpo_link);
553	l->lpo_obj = lo;
554	l->lpo_file = file;
555	l->lpo_line = line;
556	l->lpo_cnt = 0;
557	LIST_INSERT_HEAD(head, l, lpo_link);
558
559	return (l);
560}
561
562void
563lock_profile_obtain_lock_success(struct lock_object *lo, int contested,
564    uint64_t waittime, const char *file, int line)
565{
566	static int lock_prof_count;
567	struct lock_profile_object *l;
568	int spin;
569
570	if (SCHEDULER_STOPPED())
571		return;
572
573	/* don't reset the timer when/if recursing */
574	if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE))
575		return;
576	if (lock_prof_skipcount &&
577	    (++lock_prof_count % lock_prof_skipcount) != 0)
578		return;
579	spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0;
580	if (spin && lock_prof_skipspin == 1)
581		return;
582	critical_enter();
583	/* Recheck enabled now that we're in a critical section. */
584	if (lock_prof_enable == 0)
585		goto out;
586	l = lock_profile_object_lookup(lo, spin, file, line);
587	if (l == NULL)
588		goto out;
589	l->lpo_cnt++;
590	if (++l->lpo_ref > 1)
591		goto out;
592	l->lpo_contest_locking = contested;
593	l->lpo_acqtime = nanoseconds();
594	if (waittime && (l->lpo_acqtime > waittime))
595		l->lpo_waittime = l->lpo_acqtime - waittime;
596	else
597		l->lpo_waittime = 0;
598out:
599	critical_exit();
600}
601
602void
603lock_profile_thread_exit(struct thread *td)
604{
605#ifdef INVARIANTS
606	struct lock_profile_object *l;
607
608	MPASS(curthread->td_critnest == 0);
609#endif
610	/*
611	 * If lock profiling was disabled we have to wait for reset to
612	 * clear our pointers before we can exit safely.
613	 */
614	lock_prof_reset_wait();
615#ifdef INVARIANTS
616	LIST_FOREACH(l, &td->td_lprof[0], lpo_link)
617		printf("thread still holds lock acquired at %s:%d\n",
618		    l->lpo_file, l->lpo_line);
619	LIST_FOREACH(l, &td->td_lprof[1], lpo_link)
620		printf("thread still holds lock acquired at %s:%d\n",
621		    l->lpo_file, l->lpo_line);
622#endif
623	MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL);
624	MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL);
625}
626
627void
628lock_profile_release_lock(struct lock_object *lo)
629{
630	struct lock_profile_object *l;
631	struct lock_prof_type *type;
632	struct lock_prof *lp;
633	uint64_t curtime, holdtime;
634	struct lpohead *head;
635	int spin;
636
637	if (SCHEDULER_STOPPED())
638		return;
639	if (lo->lo_flags & LO_NOPROFILE)
640		return;
641	spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0;
642	head = &curthread->td_lprof[spin];
643	if (LIST_FIRST(head) == NULL)
644		return;
645	critical_enter();
646	/* Recheck enabled now that we're in a critical section. */
647	if (lock_prof_enable == 0 && lock_prof_resetting == 1)
648		goto out;
649	/*
650	 * If lock profiling is not enabled we still want to remove the
651	 * lpo from our queue.
652	 */
653	LIST_FOREACH(l, head, lpo_link)
654		if (l->lpo_obj == lo)
655			break;
656	if (l == NULL)
657		goto out;
658	if (--l->lpo_ref > 0)
659		goto out;
660	lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line);
661	if (lp == NULL)
662		goto release;
663	curtime = nanoseconds();
664	if (curtime < l->lpo_acqtime)
665		goto release;
666	holdtime = curtime - l->lpo_acqtime;
667
668	/*
669	 * Record if the lock has been held longer now than ever
670	 * before.
671	 */
672	if (holdtime > lp->cnt_max)
673		lp->cnt_max = holdtime;
674	if (l->lpo_waittime > lp->cnt_wait_max)
675		lp->cnt_wait_max = l->lpo_waittime;
676	lp->cnt_tot += holdtime;
677	lp->cnt_wait += l->lpo_waittime;
678	lp->cnt_contest_locking += l->lpo_contest_locking;
679	lp->cnt_cur += l->lpo_cnt;
680release:
681	LIST_REMOVE(l, lpo_link);
682	type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
683	LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link);
684out:
685	critical_exit();
686}
687
688static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL,
689    "lock profiling");
690SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW,
691    &lock_prof_skipspin, 0, "Skip profiling on spinlocks.");
692SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW,
693    &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions.");
694SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD,
695    &lock_prof_rejected, 0, "Number of rejected profiling records");
696SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
697    NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics");
698SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
699    NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics");
700SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW,
701    NULL, 0, enable_lock_prof, "I", "Enable lock profiling");
702
703#endif
704