675 lines
17 KiB
C
675 lines
17 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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*
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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/kernel.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/lock_profile.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/pcpu.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/sched.h>
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#include <sys/smp.h>
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#include <sys/sysctl.h>
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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#include <machine/cpufunc.h>
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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_rm,
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&lock_class_rm_sleepable,
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&lock_class_rw,
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&lock_class_lockmgr,
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};
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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(flags & LO_NEW || !lock_initialized(lock),
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("lock \"%s\" %p already initialized", 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_flags |= flags | LO_INITIALIZED;
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LOCK_LOG_INIT(lock, 0);
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WITNESS_INIT(lock, (type != NULL) ? type : name);
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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_initialized(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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void
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lock_delay(struct lock_delay_arg *la)
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{
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u_int i, delay, backoff, min, max;
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struct lock_delay_config *lc = la->config;
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delay = la->delay;
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if (delay == 0)
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delay = lc->initial;
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else {
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delay += lc->step;
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max = lc->max;
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if (delay > max)
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delay = max;
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}
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backoff = cpu_ticks() % delay;
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min = lc->min;
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if (backoff < min)
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backoff = min;
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for (i = 0; i < backoff; i++)
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cpu_spinwait();
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la->delay = delay;
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la->spin_cnt += backoff;
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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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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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/*
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* One object per-thread for each lock the thread owns. Tracks individual
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* lock instances.
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*/
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struct lock_profile_object {
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LIST_ENTRY(lock_profile_object) lpo_link;
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struct lock_object *lpo_obj;
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const char *lpo_file;
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int lpo_line;
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uint16_t lpo_ref;
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uint16_t lpo_cnt;
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uint64_t lpo_acqtime;
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uint64_t lpo_waittime;
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u_int lpo_contest_locking;
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};
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/*
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* One lock_prof for each (file, line, lock object) triple.
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*/
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struct lock_prof {
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SLIST_ENTRY(lock_prof) link;
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struct lock_class *class;
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const char *file;
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const char *name;
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int line;
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int ticks;
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uintmax_t cnt_wait_max;
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uintmax_t cnt_max;
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uintmax_t cnt_tot;
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uintmax_t cnt_wait;
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uintmax_t cnt_cur;
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uintmax_t cnt_contest_locking;
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};
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SLIST_HEAD(lphead, lock_prof);
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#define LPROF_HASH_SIZE 4096
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#define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1)
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#define LPROF_CACHE_SIZE 4096
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/*
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* Array of objects and profs for each type of object for each cpu. Spinlocks
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* are handled separately because a thread may be preempted and acquire a
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* spinlock while in the lock profiling code of a non-spinlock. In this way
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* we only need a critical section to protect the per-cpu lists.
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*/
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struct lock_prof_type {
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struct lphead lpt_lpalloc;
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struct lpohead lpt_lpoalloc;
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struct lphead lpt_hash[LPROF_HASH_SIZE];
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struct lock_prof lpt_prof[LPROF_CACHE_SIZE];
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struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE];
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};
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struct lock_prof_cpu {
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struct lock_prof_type lpc_types[2]; /* One for spin one for other. */
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};
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struct lock_prof_cpu *lp_cpu[MAXCPU];
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volatile int lock_prof_enable = 0;
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static volatile int lock_prof_resetting;
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#define LPROF_SBUF_SIZE 256
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static int lock_prof_rejected;
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static int lock_prof_skipspin;
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static int lock_prof_skipcount;
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#ifndef USE_CPU_NANOSECONDS
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uint64_t
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nanoseconds(void)
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{
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struct bintime bt;
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uint64_t ns;
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binuptime(&bt);
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/* From bintime2timespec */
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ns = bt.sec * (uint64_t)1000000000;
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ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32;
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return (ns);
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}
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#endif
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static void
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lock_prof_init_type(struct lock_prof_type *type)
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{
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int i;
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SLIST_INIT(&type->lpt_lpalloc);
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LIST_INIT(&type->lpt_lpoalloc);
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for (i = 0; i < LPROF_CACHE_SIZE; i++) {
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SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i],
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link);
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LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i],
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lpo_link);
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}
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}
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static void
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lock_prof_init(void *arg)
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{
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int cpu;
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for (cpu = 0; cpu <= mp_maxid; cpu++) {
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lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF,
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M_WAITOK | M_ZERO);
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lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]);
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lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]);
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}
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}
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SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL);
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static void
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lock_prof_reset_wait(void)
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{
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/*
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* Spin relinquishing our cpu so that quiesce_all_cpus may
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* complete.
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*/
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while (lock_prof_resetting)
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sched_relinquish(curthread);
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}
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static void
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lock_prof_reset(void)
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{
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struct lock_prof_cpu *lpc;
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int enabled, i, cpu;
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/*
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* We not only race with acquiring and releasing locks but also
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* thread exit. To be certain that threads exit without valid head
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* pointers they must see resetting set before enabled is cleared.
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* Otherwise a lock may not be removed from a per-thread list due
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* to disabled being set but not wait for reset() to remove it below.
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*/
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atomic_store_rel_int(&lock_prof_resetting, 1);
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enabled = lock_prof_enable;
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lock_prof_enable = 0;
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quiesce_all_cpus("profreset", 0);
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/*
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* Some objects may have migrated between CPUs. Clear all links
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* before we zero the structures. Some items may still be linked
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* into per-thread lists as well.
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*/
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for (cpu = 0; cpu <= mp_maxid; cpu++) {
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lpc = lp_cpu[cpu];
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for (i = 0; i < LPROF_CACHE_SIZE; i++) {
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LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link);
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LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link);
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}
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}
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for (cpu = 0; cpu <= mp_maxid; cpu++) {
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lpc = lp_cpu[cpu];
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bzero(lpc, sizeof(*lpc));
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lock_prof_init_type(&lpc->lpc_types[0]);
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lock_prof_init_type(&lpc->lpc_types[1]);
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}
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atomic_store_rel_int(&lock_prof_resetting, 0);
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lock_prof_enable = enabled;
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}
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static void
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lock_prof_output(struct lock_prof *lp, struct sbuf *sb)
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{
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const char *p;
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for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3);
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sbuf_printf(sb,
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"%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n",
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lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000,
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lp->cnt_wait / 1000, lp->cnt_cur,
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lp->cnt_cur == 0 ? (uintmax_t)0 :
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lp->cnt_tot / (lp->cnt_cur * 1000),
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lp->cnt_cur == 0 ? (uintmax_t)0 :
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lp->cnt_wait / (lp->cnt_cur * 1000),
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(uintmax_t)0, lp->cnt_contest_locking,
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p, lp->line, lp->class->lc_name, lp->name);
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}
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static void
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lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash,
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int spin, int t)
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{
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struct lock_prof_type *type;
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struct lock_prof *l;
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int cpu;
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dst->file = match->file;
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dst->line = match->line;
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dst->class = match->class;
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dst->name = match->name;
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for (cpu = 0; cpu <= mp_maxid; cpu++) {
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if (lp_cpu[cpu] == NULL)
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continue;
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type = &lp_cpu[cpu]->lpc_types[spin];
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SLIST_FOREACH(l, &type->lpt_hash[hash], link) {
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if (l->ticks == t)
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continue;
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if (l->file != match->file || l->line != match->line ||
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l->name != match->name)
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continue;
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l->ticks = t;
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if (l->cnt_max > dst->cnt_max)
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dst->cnt_max = l->cnt_max;
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if (l->cnt_wait_max > dst->cnt_wait_max)
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dst->cnt_wait_max = l->cnt_wait_max;
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dst->cnt_tot += l->cnt_tot;
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dst->cnt_wait += l->cnt_wait;
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dst->cnt_cur += l->cnt_cur;
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dst->cnt_contest_locking += l->cnt_contest_locking;
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}
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}
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}
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static void
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lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin,
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int t)
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{
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struct lock_prof *l;
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int i;
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for (i = 0; i < LPROF_HASH_SIZE; ++i) {
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SLIST_FOREACH(l, &type->lpt_hash[i], link) {
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struct lock_prof lp = {};
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if (l->ticks == t)
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continue;
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lock_prof_sum(l, &lp, i, spin, t);
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lock_prof_output(&lp, sb);
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}
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}
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}
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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, cpu, t;
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int enabled;
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error = sysctl_wire_old_buffer(req, 0);
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if (error != 0)
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return (error);
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sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req);
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sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n",
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"max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name");
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enabled = lock_prof_enable;
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lock_prof_enable = 0;
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quiesce_all_cpus("profstat", 0);
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t = ticks;
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for (cpu = 0; cpu <= mp_maxid; cpu++) {
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if (lp_cpu[cpu] == NULL)
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continue;
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lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t);
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lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t);
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}
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lock_prof_enable = enabled;
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error = sbuf_finish(sb);
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/* Output a trailing NUL. */
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if (error == 0)
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error = SYSCTL_OUT(req, "", 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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enable_lock_prof(SYSCTL_HANDLER_ARGS)
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{
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int error, v;
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v = lock_prof_enable;
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error = sysctl_handle_int(oidp, &v, v, 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 == lock_prof_enable)
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return (0);
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if (v == 1)
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lock_prof_reset();
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lock_prof_enable = !!v;
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return (0);
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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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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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lock_prof_reset();
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return (0);
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}
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static struct lock_prof *
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lock_profile_lookup(struct lock_object *lo, int spin, const char *file,
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int line)
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{
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const char *unknown = "(unknown)";
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struct lock_prof_type *type;
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struct lock_prof *lp;
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struct lphead *head;
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const char *p;
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u_int hash;
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p = file;
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if (p == NULL || *p == '\0')
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p = unknown;
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hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line;
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hash &= LPROF_HASH_MASK;
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type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
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head = &type->lpt_hash[hash];
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SLIST_FOREACH(lp, head, link) {
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if (lp->line == line && lp->file == p &&
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lp->name == lo->lo_name)
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return (lp);
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}
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lp = SLIST_FIRST(&type->lpt_lpalloc);
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if (lp == NULL) {
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lock_prof_rejected++;
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return (lp);
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}
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SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link);
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lp->file = p;
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lp->line = line;
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lp->class = LOCK_CLASS(lo);
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lp->name = lo->lo_name;
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SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link);
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return (lp);
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}
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static struct lock_profile_object *
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lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file,
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int line)
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{
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struct lock_profile_object *l;
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struct lock_prof_type *type;
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struct lpohead *head;
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head = &curthread->td_lprof[spin];
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LIST_FOREACH(l, head, lpo_link)
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if (l->lpo_obj == lo && l->lpo_file == file &&
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l->lpo_line == line)
|
|
return (l);
|
|
type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
|
|
l = LIST_FIRST(&type->lpt_lpoalloc);
|
|
if (l == NULL) {
|
|
lock_prof_rejected++;
|
|
return (NULL);
|
|
}
|
|
LIST_REMOVE(l, lpo_link);
|
|
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;
|
|
|
|
if (SCHEDULER_STOPPED())
|
|
return;
|
|
|
|
/* 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)->lc_flags & LC_SPINLOCK) ? 1 : 0;
|
|
if (spin && lock_prof_skipspin == 1)
|
|
return;
|
|
critical_enter();
|
|
/* Recheck enabled now that we're in a critical section. */
|
|
if (lock_prof_enable == 0)
|
|
goto out;
|
|
l = lock_profile_object_lookup(lo, spin, file, line);
|
|
if (l == NULL)
|
|
goto out;
|
|
l->lpo_cnt++;
|
|
if (++l->lpo_ref > 1)
|
|
goto out;
|
|
l->lpo_contest_locking = contested;
|
|
l->lpo_acqtime = nanoseconds();
|
|
if (waittime && (l->lpo_acqtime > waittime))
|
|
l->lpo_waittime = l->lpo_acqtime - waittime;
|
|
else
|
|
l->lpo_waittime = 0;
|
|
out:
|
|
critical_exit();
|
|
}
|
|
|
|
void
|
|
lock_profile_thread_exit(struct thread *td)
|
|
{
|
|
#ifdef INVARIANTS
|
|
struct lock_profile_object *l;
|
|
|
|
MPASS(curthread->td_critnest == 0);
|
|
#endif
|
|
/*
|
|
* If lock profiling was disabled we have to wait for reset to
|
|
* clear our pointers before we can exit safely.
|
|
*/
|
|
lock_prof_reset_wait();
|
|
#ifdef INVARIANTS
|
|
LIST_FOREACH(l, &td->td_lprof[0], lpo_link)
|
|
printf("thread still holds lock acquired at %s:%d\n",
|
|
l->lpo_file, l->lpo_line);
|
|
LIST_FOREACH(l, &td->td_lprof[1], lpo_link)
|
|
printf("thread still holds lock acquired at %s:%d\n",
|
|
l->lpo_file, l->lpo_line);
|
|
#endif
|
|
MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL);
|
|
MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL);
|
|
}
|
|
|
|
void
|
|
lock_profile_release_lock(struct lock_object *lo)
|
|
{
|
|
struct lock_profile_object *l;
|
|
struct lock_prof_type *type;
|
|
struct lock_prof *lp;
|
|
uint64_t curtime, holdtime;
|
|
struct lpohead *head;
|
|
int spin;
|
|
|
|
if (SCHEDULER_STOPPED())
|
|
return;
|
|
if (lo->lo_flags & LO_NOPROFILE)
|
|
return;
|
|
spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0;
|
|
head = &curthread->td_lprof[spin];
|
|
if (LIST_FIRST(head) == NULL)
|
|
return;
|
|
critical_enter();
|
|
/* Recheck enabled now that we're in a critical section. */
|
|
if (lock_prof_enable == 0 && lock_prof_resetting == 1)
|
|
goto out;
|
|
/*
|
|
* If lock profiling is not enabled we still want to remove the
|
|
* lpo from our queue.
|
|
*/
|
|
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;
|
|
curtime = nanoseconds();
|
|
if (curtime < l->lpo_acqtime)
|
|
goto release;
|
|
holdtime = curtime - l->lpo_acqtime;
|
|
|
|
/*
|
|
* Record if the lock has been held longer now than ever
|
|
* before.
|
|
*/
|
|
if (holdtime > lp->cnt_max)
|
|
lp->cnt_max = holdtime;
|
|
if (l->lpo_waittime > lp->cnt_wait_max)
|
|
lp->cnt_wait_max = l->lpo_waittime;
|
|
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();
|
|
}
|
|
|
|
static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging");
|
|
static 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
|