359 lines
12 KiB
C
359 lines
12 KiB
C
/*-
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* Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* This module holds the global variables and functions used to maintain
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* lock_object structures.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ddb.h"
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#include "opt_mprof.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/ktr.h>
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#include <sys/linker_set.h>
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#include <sys/lock.h>
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#include <sys/sbuf.h>
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#include <sys/sysctl.h>
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#include <sys/lock_profile.h>
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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CTASSERT(LOCK_CLASS_MAX == 15);
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struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = {
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&lock_class_mtx_spin,
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&lock_class_mtx_sleep,
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&lock_class_sx,
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&lock_class_rw,
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&lock_class_lockmgr,
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};
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#ifdef LOCK_PROFILING
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#include <machine/cpufunc.h>
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SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging");
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SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, "lock profiling");
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int lock_prof_enable = 0;
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SYSCTL_INT(_debug_lock_prof, OID_AUTO, enable, CTLFLAG_RW,
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&lock_prof_enable, 0, "Enable lock profiling");
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/*
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* lprof_buf is a static pool of profiling records to avoid possible
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* reentrance of the memory allocation functions.
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*
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* Note: NUM_LPROF_BUFFERS must be smaller than LPROF_HASH_SIZE.
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*/
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struct lock_prof lprof_buf[LPROF_HASH_SIZE];
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static int allocated_lprof_buf;
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struct mtx lprof_locks[LPROF_LOCK_SIZE];
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/* SWAG: sbuf size = avg stat. line size * number of locks */
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#define LPROF_SBUF_SIZE 256 * 400
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static int lock_prof_acquisitions;
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SYSCTL_INT(_debug_lock_prof, OID_AUTO, acquisitions, CTLFLAG_RD,
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&lock_prof_acquisitions, 0, "Number of lock acquistions recorded");
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static int lock_prof_records;
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SYSCTL_INT(_debug_lock_prof, OID_AUTO, records, CTLFLAG_RD,
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&lock_prof_records, 0, "Number of profiling records");
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static int lock_prof_maxrecords = LPROF_HASH_SIZE;
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SYSCTL_INT(_debug_lock_prof, OID_AUTO, maxrecords, CTLFLAG_RD,
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&lock_prof_maxrecords, 0, "Maximum number of profiling records");
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static int lock_prof_rejected;
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SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD,
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&lock_prof_rejected, 0, "Number of rejected profiling records");
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static int lock_prof_hashsize = LPROF_HASH_SIZE;
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SYSCTL_INT(_debug_lock_prof, OID_AUTO, hashsize, CTLFLAG_RD,
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&lock_prof_hashsize, 0, "Hash size");
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static int lock_prof_collisions = 0;
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SYSCTL_INT(_debug_lock_prof, OID_AUTO, collisions, CTLFLAG_RD,
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&lock_prof_collisions, 0, "Number of hash collisions");
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#ifndef USE_CPU_NANOSECONDS
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u_int64_t
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nanoseconds(void)
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{
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struct timespec tv;
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nanotime(&tv);
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return (tv.tv_sec * (u_int64_t)1000000000 + tv.tv_nsec);
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}
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#endif
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static int
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dump_lock_prof_stats(SYSCTL_HANDLER_ARGS)
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{
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struct sbuf *sb;
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int error, i;
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static int multiplier = 1;
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const char *p;
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if (allocated_lprof_buf == 0)
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return (SYSCTL_OUT(req, "No locking recorded",
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sizeof("No locking recorded")));
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retry_sbufops:
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sb = sbuf_new(NULL, NULL, LPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
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sbuf_printf(sb, "\n%6s %12s %12s %11s %5s %5s %12s %12s %s\n",
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"max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name");
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for (i = 0; i < LPROF_HASH_SIZE; ++i) {
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if (lprof_buf[i].name == NULL)
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continue;
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for (p = lprof_buf[i].file;
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p != NULL && strncmp(p, "../", 3) == 0; p += 3)
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/* nothing */ ;
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sbuf_printf(sb, "%6ju %12ju %12ju %11ju %5ju %5ju %12ju %12ju %s:%d (%s:%s)\n",
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lprof_buf[i].cnt_max / 1000,
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lprof_buf[i].cnt_tot / 1000,
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lprof_buf[i].cnt_wait / 1000,
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lprof_buf[i].cnt_cur,
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lprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
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lprof_buf[i].cnt_tot / (lprof_buf[i].cnt_cur * 1000),
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lprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
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lprof_buf[i].cnt_wait / (lprof_buf[i].cnt_cur * 1000),
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lprof_buf[i].cnt_contest_holding,
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lprof_buf[i].cnt_contest_locking,
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p, lprof_buf[i].line,
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lprof_buf[i].type,
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lprof_buf[i].name);
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if (sbuf_overflowed(sb)) {
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sbuf_delete(sb);
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multiplier++;
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goto retry_sbufops;
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}
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}
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sbuf_finish(sb);
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error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
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sbuf_delete(sb);
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return (error);
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}
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static int
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reset_lock_prof_stats(SYSCTL_HANDLER_ARGS)
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{
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int error, v;
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if (allocated_lprof_buf == 0)
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return (0);
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v = 0;
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error = sysctl_handle_int(oidp, &v, 0, req);
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if (error)
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return (error);
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if (req->newptr == NULL)
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return (error);
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if (v == 0)
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return (0);
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bzero(lprof_buf, LPROF_HASH_SIZE*sizeof(*lprof_buf));
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allocated_lprof_buf = 0;
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return (0);
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}
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SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
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NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics");
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SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
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NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics");
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#endif
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void
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lock_init(struct lock_object *lock, struct lock_class *class, const char *name,
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const char *type, int flags)
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{
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int i;
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/* Check for double-init and zero object. */
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KASSERT(!lock_initalized(lock), ("lock \"%s\" %p already initialized",
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name, lock));
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/* Look up lock class to find its index. */
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for (i = 0; i < LOCK_CLASS_MAX; i++)
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if (lock_classes[i] == class) {
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lock->lo_flags = i << LO_CLASSSHIFT;
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break;
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}
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KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class));
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/* Initialize the lock object. */
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lock->lo_name = name;
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lock->lo_type = type != NULL ? type : name;
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lock->lo_flags |= flags | LO_INITIALIZED;
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LOCK_LOG_INIT(lock, 0);
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WITNESS_INIT(lock);
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}
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void
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lock_destroy(struct lock_object *lock)
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{
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KASSERT(lock_initalized(lock), ("lock %p is not initialized", lock));
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WITNESS_DESTROY(lock);
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LOCK_LOG_DESTROY(lock, 0);
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lock->lo_flags &= ~LO_INITIALIZED;
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}
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#ifdef DDB
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DB_SHOW_COMMAND(lock, db_show_lock)
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{
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struct lock_object *lock;
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struct lock_class *class;
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if (!have_addr)
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return;
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lock = (struct lock_object *)addr;
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if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) {
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db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock));
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return;
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}
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class = LOCK_CLASS(lock);
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db_printf(" class: %s\n", class->lc_name);
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db_printf(" name: %s\n", lock->lo_name);
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if (lock->lo_type && lock->lo_type != lock->lo_name)
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db_printf(" type: %s\n", lock->lo_type);
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class->lc_ddb_show(lock);
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}
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#endif
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#ifdef LOCK_PROFILING
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void _lock_profile_obtain_lock_success(struct lock_object *lo, int contested, uint64_t waittime, const char *file, int line)
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{
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struct lock_profile_object *l = &lo->lo_profile_obj;
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lo->lo_profile_obj.lpo_contest_holding = 0;
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if (contested)
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lo->lo_profile_obj.lpo_contest_locking++;
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l->lpo_filename = file;
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l->lpo_lineno = line;
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l->lpo_acqtime = nanoseconds();
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if (waittime && (l->lpo_acqtime > waittime))
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l->lpo_waittime = l->lpo_acqtime - waittime;
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else
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l->lpo_waittime = 0;
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}
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void _lock_profile_release_lock(struct lock_object *lo)
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{
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struct lock_profile_object *l = &lo->lo_profile_obj;
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if (l->lpo_acqtime && !(lo->lo_flags & LO_NOPROFILE)) {
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const char *unknown = "(unknown)";
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u_int64_t acqtime, now, waittime;
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struct lock_prof *mpp;
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u_int hash;
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const char *p = l->lpo_filename;
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int collision = 0;
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now = nanoseconds();
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acqtime = l->lpo_acqtime;
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waittime = l->lpo_waittime;
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if (now <= acqtime)
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return;
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if (p == NULL || *p == '\0')
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p = unknown;
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hash = (l->lpo_namehash * 31 * 31 + (uintptr_t)p * 31 + l->lpo_lineno) & LPROF_HASH_MASK;
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CTR5(KTR_SPARE1, "Hashing %s(%x) %s:%d to %d", l->lpo_filename,
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l->lpo_namehash, p, l->lpo_lineno, hash);
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mpp = &lprof_buf[hash];
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while (mpp->name != NULL) {
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if (mpp->line == l->lpo_lineno &&
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mpp->file == p &&
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mpp->namehash == l->lpo_namehash)
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break;
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/* If the lprof_hash entry is allocated to someone
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* else, try the next one
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*/
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collision = 1;
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CTR4(KTR_SPARE1, "Hash collision, %s:%d %s(%x)", mpp->file,
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mpp->line, mpp->name, mpp->namehash);
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hash = (hash + 1) & LPROF_HASH_MASK;
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mpp = &lprof_buf[hash];
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}
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if (mpp->name == NULL) {
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int buf;
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buf = atomic_fetchadd_int(&allocated_lprof_buf, 1);
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/* Just exit if we cannot get a trace buffer */
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if (buf >= LPROF_HASH_SIZE) {
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++lock_prof_rejected;
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return;
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}
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mpp->file = p;
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mpp->line = l->lpo_lineno;
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mpp->namehash = l->lpo_namehash;
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mpp->type = l->lpo_type;
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mpp->name = lo->lo_name;
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if (collision)
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++lock_prof_collisions;
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/*
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* We might have raced someone else but who cares,
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* they'll try again next time
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*/
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++lock_prof_records;
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}
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LPROF_LOCK(hash);
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/*
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* Record if the lock has been held longer now than ever
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* before.
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*/
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if (now - acqtime > mpp->cnt_max)
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mpp->cnt_max = now - acqtime;
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mpp->cnt_tot += now - acqtime;
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mpp->cnt_wait += waittime;
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mpp->cnt_cur++;
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/*
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* There's a small race, really we should cmpxchg
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* 0 with the current value, but that would bill
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* the contention to the wrong lock instance if
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* it followed this also.
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*/
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mpp->cnt_contest_holding += l->lpo_contest_holding;
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mpp->cnt_contest_locking += l->lpo_contest_locking;
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LPROF_UNLOCK(hash);
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}
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l->lpo_acqtime = 0;
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l->lpo_waittime = 0;
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l->lpo_contest_locking = 0;
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l->lpo_contest_holding = 0;
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}
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#endif
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