2005-01-06 23:35:40 +00:00
|
|
|
/*-
|
2007-03-31 23:23:42 +00:00
|
|
|
* Copyright (c) 2007 Attilio Rao <attilio@freebsd.org>
|
|
|
|
* Copyright (c) 2001 Jason Evans <jasone@freebsd.org>
|
|
|
|
* All rights reserved.
|
2001-03-05 19:59:41 +00:00
|
|
|
*
|
|
|
|
* Redistribution and use in source and binary forms, with or without
|
|
|
|
* modification, are permitted provided that the following conditions
|
|
|
|
* are met:
|
|
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
|
|
* notice(s), this list of conditions and the following disclaimer as
|
2007-03-31 23:23:42 +00:00
|
|
|
* the first lines of this file unmodified other than the possible
|
2001-03-05 19:59:41 +00:00
|
|
|
* addition of one or more copyright notices.
|
|
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
|
|
* notice(s), this list of conditions and the following disclaimer in the
|
|
|
|
* documentation and/or other materials provided with the distribution.
|
|
|
|
*
|
|
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
|
|
|
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
|
|
|
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
|
|
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
|
|
|
|
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
|
|
|
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
|
|
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
|
|
|
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
|
|
|
|
* DAMAGE.
|
|
|
|
*/
|
|
|
|
|
|
|
|
/*
|
2007-03-31 23:23:42 +00:00
|
|
|
* Shared/exclusive locks. This implementation attempts to ensure
|
|
|
|
* deterministic lock granting behavior, so that slocks and xlocks are
|
|
|
|
* interleaved.
|
2001-03-05 19:59:41 +00:00
|
|
|
*
|
|
|
|
* Priority propagation will not generally raise the priority of lock holders,
|
|
|
|
* so should not be relied upon in combination with sx locks.
|
|
|
|
*/
|
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
#include "opt_adaptive_sx.h"
|
|
|
|
#include "opt_ddb.h"
|
|
|
|
|
2003-06-11 00:56:59 +00:00
|
|
|
#include <sys/cdefs.h>
|
|
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
|
2001-03-05 19:59:41 +00:00
|
|
|
#include <sys/param.h>
|
|
|
|
#include <sys/ktr.h>
|
Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
2001-03-28 09:03:24 +00:00
|
|
|
#include <sys/lock.h>
|
2001-03-05 19:59:41 +00:00
|
|
|
#include <sys/mutex.h>
|
2005-12-13 23:14:35 +00:00
|
|
|
#include <sys/proc.h>
|
2007-03-31 23:23:42 +00:00
|
|
|
#include <sys/sleepqueue.h>
|
2001-03-05 19:59:41 +00:00
|
|
|
#include <sys/sx.h>
|
2007-03-31 23:23:42 +00:00
|
|
|
#include <sys/systm.h>
|
|
|
|
|
|
|
|
#ifdef ADAPTIVE_SX
|
|
|
|
#include <machine/cpu.h>
|
|
|
|
#endif
|
2001-03-05 19:59:41 +00:00
|
|
|
|
2006-08-15 18:29:01 +00:00
|
|
|
#ifdef DDB
|
2005-12-13 23:14:35 +00:00
|
|
|
#include <ddb/ddb.h>
|
2007-03-31 23:23:42 +00:00
|
|
|
#endif
|
|
|
|
|
|
|
|
#if !defined(SMP) && defined(ADAPTIVE_SX)
|
|
|
|
#error "You must have SMP to enable the ADAPTIVE_SX option"
|
|
|
|
#endif
|
|
|
|
|
2007-07-06 13:20:44 +00:00
|
|
|
CTASSERT(((SX_ADAPTIVESPIN | SX_RECURSE) & LO_CLASSFLAGS) ==
|
|
|
|
(SX_ADAPTIVESPIN | SX_RECURSE));
|
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/* Handy macros for sleep queues. */
|
|
|
|
#define SQ_EXCLUSIVE_QUEUE 0
|
|
|
|
#define SQ_SHARED_QUEUE 1
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Variations on DROP_GIANT()/PICKUP_GIANT() for use in this file. We
|
|
|
|
* drop Giant anytime we have to sleep or if we adaptively spin.
|
|
|
|
*/
|
|
|
|
#define GIANT_DECLARE \
|
|
|
|
int _giantcnt = 0; \
|
|
|
|
WITNESS_SAVE_DECL(Giant) \
|
|
|
|
|
|
|
|
#define GIANT_SAVE() do { \
|
|
|
|
if (mtx_owned(&Giant)) { \
|
|
|
|
WITNESS_SAVE(&Giant.lock_object, Giant); \
|
|
|
|
while (mtx_owned(&Giant)) { \
|
|
|
|
_giantcnt++; \
|
|
|
|
mtx_unlock(&Giant); \
|
|
|
|
} \
|
|
|
|
} \
|
|
|
|
} while (0)
|
|
|
|
|
|
|
|
#define GIANT_RESTORE() do { \
|
|
|
|
if (_giantcnt > 0) { \
|
|
|
|
mtx_assert(&Giant, MA_NOTOWNED); \
|
|
|
|
while (_giantcnt--) \
|
|
|
|
mtx_lock(&Giant); \
|
|
|
|
WITNESS_RESTORE(&Giant.lock_object, Giant); \
|
|
|
|
} \
|
|
|
|
} while (0)
|
|
|
|
|
|
|
|
/*
|
2007-05-18 15:05:41 +00:00
|
|
|
* Returns true if an exclusive lock is recursed. It assumes
|
|
|
|
* curthread currently has an exclusive lock.
|
2007-03-31 23:23:42 +00:00
|
|
|
*/
|
2008-05-15 20:10:06 +00:00
|
|
|
#define sx_recurse lock_object.lo_data
|
2007-03-31 23:23:42 +00:00
|
|
|
#define sx_recursed(sx) ((sx)->sx_recurse != 0)
|
|
|
|
|
2007-11-18 14:43:53 +00:00
|
|
|
static void assert_sx(struct lock_object *lock, int what);
|
2007-03-31 23:23:42 +00:00
|
|
|
#ifdef DDB
|
2005-12-13 23:14:35 +00:00
|
|
|
static void db_show_sx(struct lock_object *lock);
|
|
|
|
#endif
|
2007-03-09 16:27:11 +00:00
|
|
|
static void lock_sx(struct lock_object *lock, int how);
|
|
|
|
static int unlock_sx(struct lock_object *lock);
|
2005-12-13 23:14:35 +00:00
|
|
|
|
Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
2001-03-28 09:03:24 +00:00
|
|
|
struct lock_class lock_class_sx = {
|
2007-03-09 16:04:44 +00:00
|
|
|
.lc_name = "sx",
|
|
|
|
.lc_flags = LC_SLEEPLOCK | LC_SLEEPABLE | LC_RECURSABLE | LC_UPGRADABLE,
|
2007-11-18 14:43:53 +00:00
|
|
|
.lc_assert = assert_sx,
|
2005-12-13 23:14:35 +00:00
|
|
|
#ifdef DDB
|
2007-03-09 16:04:44 +00:00
|
|
|
.lc_ddb_show = db_show_sx,
|
2005-12-13 23:14:35 +00:00
|
|
|
#endif
|
2007-03-09 16:27:11 +00:00
|
|
|
.lc_lock = lock_sx,
|
|
|
|
.lc_unlock = unlock_sx,
|
Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
2001-03-28 09:03:24 +00:00
|
|
|
};
|
|
|
|
|
2001-10-24 14:18:33 +00:00
|
|
|
#ifndef INVARIANTS
|
|
|
|
#define _sx_assert(sx, what, file, line)
|
|
|
|
#endif
|
|
|
|
|
2007-11-18 14:43:53 +00:00
|
|
|
void
|
|
|
|
assert_sx(struct lock_object *lock, int what)
|
|
|
|
{
|
|
|
|
|
|
|
|
sx_assert((struct sx *)lock, what);
|
|
|
|
}
|
|
|
|
|
2007-03-09 16:27:11 +00:00
|
|
|
void
|
|
|
|
lock_sx(struct lock_object *lock, int how)
|
|
|
|
{
|
|
|
|
struct sx *sx;
|
|
|
|
|
|
|
|
sx = (struct sx *)lock;
|
|
|
|
if (how)
|
|
|
|
sx_xlock(sx);
|
|
|
|
else
|
|
|
|
sx_slock(sx);
|
|
|
|
}
|
|
|
|
|
|
|
|
int
|
|
|
|
unlock_sx(struct lock_object *lock)
|
|
|
|
{
|
|
|
|
struct sx *sx;
|
|
|
|
|
|
|
|
sx = (struct sx *)lock;
|
2007-05-19 21:26:05 +00:00
|
|
|
sx_assert(sx, SA_LOCKED | SA_NOTRECURSED);
|
2007-03-09 16:27:11 +00:00
|
|
|
if (sx_xlocked(sx)) {
|
|
|
|
sx_xunlock(sx);
|
|
|
|
return (1);
|
|
|
|
} else {
|
|
|
|
sx_sunlock(sx);
|
|
|
|
return (0);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2002-04-02 16:05:43 +00:00
|
|
|
void
|
|
|
|
sx_sysinit(void *arg)
|
|
|
|
{
|
|
|
|
struct sx_args *sargs = arg;
|
|
|
|
|
|
|
|
sx_init(sargs->sa_sx, sargs->sa_desc);
|
|
|
|
}
|
|
|
|
|
2001-03-05 19:59:41 +00:00
|
|
|
void
|
2007-03-31 23:23:42 +00:00
|
|
|
sx_init_flags(struct sx *sx, const char *description, int opts)
|
2001-03-05 19:59:41 +00:00
|
|
|
{
|
2007-03-31 23:23:42 +00:00
|
|
|
int flags;
|
|
|
|
|
2007-05-19 16:35:27 +00:00
|
|
|
MPASS((opts & ~(SX_QUIET | SX_RECURSE | SX_NOWITNESS | SX_DUPOK |
|
2007-05-19 18:34:24 +00:00
|
|
|
SX_NOPROFILE | SX_ADAPTIVESPIN)) == 0);
|
2007-05-19 16:35:27 +00:00
|
|
|
|
2007-05-29 19:46:37 +00:00
|
|
|
flags = LO_RECURSABLE | LO_SLEEPABLE | LO_UPGRADABLE;
|
2007-03-31 23:23:42 +00:00
|
|
|
if (opts & SX_DUPOK)
|
|
|
|
flags |= LO_DUPOK;
|
|
|
|
if (opts & SX_NOPROFILE)
|
|
|
|
flags |= LO_NOPROFILE;
|
|
|
|
if (!(opts & SX_NOWITNESS))
|
|
|
|
flags |= LO_WITNESS;
|
|
|
|
if (opts & SX_QUIET)
|
|
|
|
flags |= LO_QUIET;
|
|
|
|
|
2007-05-19 16:35:27 +00:00
|
|
|
flags |= opts & (SX_ADAPTIVESPIN | SX_RECURSE);
|
2007-03-31 23:23:42 +00:00
|
|
|
sx->sx_lock = SX_LOCK_UNLOCKED;
|
|
|
|
sx->sx_recurse = 0;
|
|
|
|
lock_init(&sx->lock_object, &lock_class_sx, description, NULL, flags);
|
2001-03-05 19:59:41 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
sx_destroy(struct sx *sx)
|
|
|
|
{
|
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
KASSERT(sx->sx_lock == SX_LOCK_UNLOCKED, ("sx lock still held"));
|
|
|
|
KASSERT(sx->sx_recurse == 0, ("sx lock still recursed"));
|
2007-05-08 21:51:37 +00:00
|
|
|
sx->sx_lock = SX_LOCK_DESTROYED;
|
2007-03-21 21:20:51 +00:00
|
|
|
lock_destroy(&sx->lock_object);
|
2001-03-05 19:59:41 +00:00
|
|
|
}
|
|
|
|
|
2007-05-31 09:14:48 +00:00
|
|
|
int
|
|
|
|
_sx_slock(struct sx *sx, int opts, const char *file, int line)
|
2001-03-05 19:59:41 +00:00
|
|
|
{
|
2007-05-31 09:14:48 +00:00
|
|
|
int error = 0;
|
2001-03-05 19:59:41 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
MPASS(curthread != NULL);
|
2007-05-08 21:51:37 +00:00
|
|
|
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
|
|
|
|
("sx_slock() of destroyed sx @ %s:%d", file, line));
|
2007-03-21 21:20:51 +00:00
|
|
|
WITNESS_CHECKORDER(&sx->lock_object, LOP_NEWORDER, file, line);
|
2007-05-31 09:14:48 +00:00
|
|
|
error = __sx_slock(sx, opts, file, line);
|
|
|
|
if (!error) {
|
|
|
|
LOCK_LOG_LOCK("SLOCK", &sx->lock_object, 0, 0, file, line);
|
|
|
|
WITNESS_LOCK(&sx->lock_object, 0, file, line);
|
|
|
|
curthread->td_locks++;
|
|
|
|
}
|
|
|
|
|
|
|
|
return (error);
|
2001-03-05 19:59:41 +00:00
|
|
|
}
|
|
|
|
|
2001-06-27 06:39:37 +00:00
|
|
|
int
|
|
|
|
_sx_try_slock(struct sx *sx, const char *file, int line)
|
|
|
|
{
|
2007-03-31 23:23:42 +00:00
|
|
|
uintptr_t x;
|
2001-06-27 06:39:37 +00:00
|
|
|
|
2007-10-02 14:48:48 +00:00
|
|
|
for (;;) {
|
|
|
|
x = sx->sx_lock;
|
|
|
|
KASSERT(x != SX_LOCK_DESTROYED,
|
|
|
|
("sx_try_slock() of destroyed sx @ %s:%d", file, line));
|
|
|
|
if (!(x & SX_LOCK_SHARED))
|
|
|
|
break;
|
|
|
|
if (atomic_cmpset_acq_ptr(&sx->sx_lock, x, x + SX_ONE_SHARER)) {
|
|
|
|
LOCK_LOG_TRY("SLOCK", &sx->lock_object, 0, 1, file, line);
|
|
|
|
WITNESS_LOCK(&sx->lock_object, LOP_TRYLOCK, file, line);
|
|
|
|
curthread->td_locks++;
|
|
|
|
return (1);
|
|
|
|
}
|
2001-06-27 06:39:37 +00:00
|
|
|
}
|
2007-03-31 23:23:42 +00:00
|
|
|
|
|
|
|
LOCK_LOG_TRY("SLOCK", &sx->lock_object, 0, 0, file, line);
|
|
|
|
return (0);
|
2001-06-27 06:39:37 +00:00
|
|
|
}
|
|
|
|
|
2007-05-31 09:14:48 +00:00
|
|
|
int
|
|
|
|
_sx_xlock(struct sx *sx, int opts, const char *file, int line)
|
2001-03-05 19:59:41 +00:00
|
|
|
{
|
2007-05-31 09:14:48 +00:00
|
|
|
int error = 0;
|
2001-03-05 19:59:41 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
MPASS(curthread != NULL);
|
2007-05-08 21:51:37 +00:00
|
|
|
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
|
|
|
|
("sx_xlock() of destroyed sx @ %s:%d", file, line));
|
2007-03-21 21:20:51 +00:00
|
|
|
WITNESS_CHECKORDER(&sx->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE, file,
|
2004-01-28 20:39:57 +00:00
|
|
|
line);
|
2007-05-31 09:14:48 +00:00
|
|
|
error = __sx_xlock(sx, curthread, opts, file, line);
|
|
|
|
if (!error) {
|
|
|
|
LOCK_LOG_LOCK("XLOCK", &sx->lock_object, 0, sx->sx_recurse,
|
|
|
|
file, line);
|
|
|
|
WITNESS_LOCK(&sx->lock_object, LOP_EXCLUSIVE, file, line);
|
|
|
|
curthread->td_locks++;
|
|
|
|
}
|
|
|
|
|
|
|
|
return (error);
|
2001-03-05 19:59:41 +00:00
|
|
|
}
|
|
|
|
|
2001-06-27 06:39:37 +00:00
|
|
|
int
|
|
|
|
_sx_try_xlock(struct sx *sx, const char *file, int line)
|
|
|
|
{
|
2007-03-31 23:23:42 +00:00
|
|
|
int rval;
|
2001-06-27 06:39:37 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
MPASS(curthread != NULL);
|
2007-05-08 21:51:37 +00:00
|
|
|
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
|
|
|
|
("sx_try_xlock() of destroyed sx @ %s:%d", file, line));
|
2007-03-31 23:23:42 +00:00
|
|
|
|
2007-05-19 16:35:27 +00:00
|
|
|
if (sx_xlocked(sx) && (sx->lock_object.lo_flags & SX_RECURSE) != 0) {
|
2007-03-31 23:23:42 +00:00
|
|
|
sx->sx_recurse++;
|
|
|
|
atomic_set_ptr(&sx->sx_lock, SX_LOCK_RECURSED);
|
|
|
|
rval = 1;
|
|
|
|
} else
|
|
|
|
rval = atomic_cmpset_acq_ptr(&sx->sx_lock, SX_LOCK_UNLOCKED,
|
|
|
|
(uintptr_t)curthread);
|
|
|
|
LOCK_LOG_TRY("XLOCK", &sx->lock_object, 0, rval, file, line);
|
|
|
|
if (rval) {
|
|
|
|
WITNESS_LOCK(&sx->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK,
|
|
|
|
file, line);
|
2006-07-27 21:45:55 +00:00
|
|
|
curthread->td_locks++;
|
2001-06-27 06:39:37 +00:00
|
|
|
}
|
2007-03-31 23:23:42 +00:00
|
|
|
|
|
|
|
return (rval);
|
2001-06-27 06:39:37 +00:00
|
|
|
}
|
|
|
|
|
2001-03-05 19:59:41 +00:00
|
|
|
void
|
Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
2001-03-28 09:03:24 +00:00
|
|
|
_sx_sunlock(struct sx *sx, const char *file, int line)
|
2001-03-05 19:59:41 +00:00
|
|
|
{
|
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
MPASS(curthread != NULL);
|
2007-05-08 21:51:37 +00:00
|
|
|
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
|
|
|
|
("sx_sunlock() of destroyed sx @ %s:%d", file, line));
|
2007-05-19 21:26:05 +00:00
|
|
|
_sx_assert(sx, SA_SLOCKED, file, line);
|
2006-07-27 21:45:55 +00:00
|
|
|
curthread->td_locks--;
|
2007-03-21 21:20:51 +00:00
|
|
|
WITNESS_UNLOCK(&sx->lock_object, 0, file, line);
|
2007-03-31 23:23:42 +00:00
|
|
|
LOCK_LOG_LOCK("SUNLOCK", &sx->lock_object, 0, 0, file, line);
|
|
|
|
__sx_sunlock(sx, file, line);
|
2007-12-15 23:13:31 +00:00
|
|
|
lock_profile_release_lock(&sx->lock_object);
|
2007-03-31 23:23:42 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
_sx_xunlock(struct sx *sx, const char *file, int line)
|
|
|
|
{
|
|
|
|
|
|
|
|
MPASS(curthread != NULL);
|
2007-05-08 21:51:37 +00:00
|
|
|
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
|
|
|
|
("sx_xunlock() of destroyed sx @ %s:%d", file, line));
|
2007-05-19 21:26:05 +00:00
|
|
|
_sx_assert(sx, SA_XLOCKED, file, line);
|
2007-03-31 23:23:42 +00:00
|
|
|
curthread->td_locks--;
|
|
|
|
WITNESS_UNLOCK(&sx->lock_object, LOP_EXCLUSIVE, file, line);
|
|
|
|
LOCK_LOG_LOCK("XUNLOCK", &sx->lock_object, 0, sx->sx_recurse, file,
|
|
|
|
line);
|
2007-04-03 22:58:21 +00:00
|
|
|
if (!sx_recursed(sx))
|
|
|
|
lock_profile_release_lock(&sx->lock_object);
|
2007-03-31 23:23:42 +00:00
|
|
|
__sx_xunlock(sx, curthread, file, line);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Try to do a non-blocking upgrade from a shared lock to an exclusive lock.
|
|
|
|
* This will only succeed if this thread holds a single shared lock.
|
|
|
|
* Return 1 if if the upgrade succeed, 0 otherwise.
|
|
|
|
*/
|
|
|
|
int
|
|
|
|
_sx_try_upgrade(struct sx *sx, const char *file, int line)
|
|
|
|
{
|
|
|
|
uintptr_t x;
|
|
|
|
int success;
|
|
|
|
|
2007-05-08 21:51:37 +00:00
|
|
|
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
|
|
|
|
("sx_try_upgrade() of destroyed sx @ %s:%d", file, line));
|
2007-05-19 21:26:05 +00:00
|
|
|
_sx_assert(sx, SA_SLOCKED, file, line);
|
2007-03-31 23:23:42 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Try to switch from one shared lock to an exclusive lock. We need
|
|
|
|
* to maintain the SX_LOCK_EXCLUSIVE_WAITERS flag if set so that
|
|
|
|
* we will wake up the exclusive waiters when we drop the lock.
|
|
|
|
*/
|
|
|
|
x = sx->sx_lock & SX_LOCK_EXCLUSIVE_WAITERS;
|
|
|
|
success = atomic_cmpset_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1) | x,
|
|
|
|
(uintptr_t)curthread | x);
|
|
|
|
LOCK_LOG_TRY("XUPGRADE", &sx->lock_object, 0, success, file, line);
|
|
|
|
if (success)
|
|
|
|
WITNESS_UPGRADE(&sx->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK,
|
|
|
|
file, line);
|
|
|
|
return (success);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Downgrade an unrecursed exclusive lock into a single shared lock.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
_sx_downgrade(struct sx *sx, const char *file, int line)
|
|
|
|
{
|
|
|
|
uintptr_t x;
|
|
|
|
|
2007-05-08 21:51:37 +00:00
|
|
|
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
|
|
|
|
("sx_downgrade() of destroyed sx @ %s:%d", file, line));
|
2007-05-19 21:26:05 +00:00
|
|
|
_sx_assert(sx, SA_XLOCKED | SA_NOTRECURSED, file, line);
|
2007-03-31 23:23:42 +00:00
|
|
|
#ifndef INVARIANTS
|
|
|
|
if (sx_recursed(sx))
|
|
|
|
panic("downgrade of a recursed lock");
|
|
|
|
#endif
|
Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
2001-03-28 09:03:24 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
WITNESS_DOWNGRADE(&sx->lock_object, 0, file, line);
|
2001-03-05 19:59:41 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* Try to switch from an exclusive lock with no shared waiters
|
|
|
|
* to one sharer with no shared waiters. If there are
|
|
|
|
* exclusive waiters, we don't need to lock the sleep queue so
|
|
|
|
* long as we preserve the flag. We do one quick try and if
|
|
|
|
* that fails we grab the sleepq lock to keep the flags from
|
|
|
|
* changing and do it the slow way.
|
|
|
|
*
|
|
|
|
* We have to lock the sleep queue if there are shared waiters
|
|
|
|
* so we can wake them up.
|
|
|
|
*/
|
|
|
|
x = sx->sx_lock;
|
|
|
|
if (!(x & SX_LOCK_SHARED_WAITERS) &&
|
|
|
|
atomic_cmpset_rel_ptr(&sx->sx_lock, x, SX_SHARERS_LOCK(1) |
|
|
|
|
(x & SX_LOCK_EXCLUSIVE_WAITERS))) {
|
|
|
|
LOCK_LOG_LOCK("XDOWNGRADE", &sx->lock_object, 0, 0, file, line);
|
|
|
|
return;
|
2007-02-27 06:42:05 +00:00
|
|
|
}
|
2007-03-02 07:21:20 +00:00
|
|
|
|
2001-03-05 19:59:41 +00:00
|
|
|
/*
|
2007-03-31 23:23:42 +00:00
|
|
|
* Lock the sleep queue so we can read the waiters bits
|
|
|
|
* without any races and wakeup any shared waiters.
|
2001-03-05 19:59:41 +00:00
|
|
|
*/
|
2007-03-31 23:23:42 +00:00
|
|
|
sleepq_lock(&sx->lock_object);
|
2001-03-05 19:59:41 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* Preserve SX_LOCK_EXCLUSIVE_WAITERS while downgraded to a single
|
|
|
|
* shared lock. If there are any shared waiters, wake them up.
|
|
|
|
*/
|
|
|
|
x = sx->sx_lock;
|
|
|
|
atomic_store_rel_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1) |
|
|
|
|
(x & SX_LOCK_EXCLUSIVE_WAITERS));
|
|
|
|
if (x & SX_LOCK_SHARED_WAITERS)
|
2008-03-12 06:31:06 +00:00
|
|
|
sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0,
|
2007-03-31 23:23:42 +00:00
|
|
|
SQ_SHARED_QUEUE);
|
2008-03-12 06:31:06 +00:00
|
|
|
sleepq_release(&sx->lock_object);
|
Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
2001-03-28 09:03:24 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
LOCK_LOG_LOCK("XDOWNGRADE", &sx->lock_object, 0, 0, file, line);
|
2001-03-05 19:59:41 +00:00
|
|
|
}
|
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* This function represents the so-called 'hard case' for sx_xlock
|
|
|
|
* operation. All 'easy case' failures are redirected to this. Note
|
|
|
|
* that ideally this would be a static function, but it needs to be
|
|
|
|
* accessible from at least sx.h.
|
|
|
|
*/
|
2007-05-31 09:14:48 +00:00
|
|
|
int
|
|
|
|
_sx_xlock_hard(struct sx *sx, uintptr_t tid, int opts, const char *file,
|
|
|
|
int line)
|
2001-03-05 19:59:41 +00:00
|
|
|
{
|
2007-03-31 23:23:42 +00:00
|
|
|
GIANT_DECLARE;
|
|
|
|
#ifdef ADAPTIVE_SX
|
|
|
|
volatile struct thread *owner;
|
|
|
|
#endif
|
2007-07-06 13:20:44 +00:00
|
|
|
uint64_t waittime = 0;
|
2007-03-31 23:23:42 +00:00
|
|
|
uintptr_t x;
|
2007-05-31 09:14:48 +00:00
|
|
|
int contested = 0, error = 0;
|
2001-03-05 19:59:41 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/* If we already hold an exclusive lock, then recurse. */
|
|
|
|
if (sx_xlocked(sx)) {
|
2007-05-19 16:35:27 +00:00
|
|
|
KASSERT((sx->lock_object.lo_flags & SX_RECURSE) != 0,
|
|
|
|
("_sx_xlock_hard: recursed on non-recursive sx %s @ %s:%d\n",
|
2007-07-06 13:20:44 +00:00
|
|
|
sx->lock_object.lo_name, file, line));
|
2007-03-31 23:23:42 +00:00
|
|
|
sx->sx_recurse++;
|
|
|
|
atomic_set_ptr(&sx->sx_lock, SX_LOCK_RECURSED);
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p recursing", __func__, sx);
|
2007-05-31 09:14:48 +00:00
|
|
|
return (0);
|
2007-03-31 23:23:42 +00:00
|
|
|
}
|
Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
2001-03-28 09:03:24 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR5(KTR_LOCK, "%s: %s contested (lock=%p) at %s:%d", __func__,
|
|
|
|
sx->lock_object.lo_name, (void *)sx->sx_lock, file, line);
|
2001-03-05 19:59:41 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
while (!atomic_cmpset_acq_ptr(&sx->sx_lock, SX_LOCK_UNLOCKED, tid)) {
|
2007-12-15 23:13:31 +00:00
|
|
|
lock_profile_obtain_lock_failed(&sx->lock_object, &contested,
|
|
|
|
&waittime);
|
2007-03-31 23:23:42 +00:00
|
|
|
#ifdef ADAPTIVE_SX
|
|
|
|
/*
|
|
|
|
* If the lock is write locked and the owner is
|
|
|
|
* running on another CPU, spin until the owner stops
|
|
|
|
* running or the state of the lock changes.
|
|
|
|
*/
|
|
|
|
x = sx->sx_lock;
|
|
|
|
if (!(x & SX_LOCK_SHARED) &&
|
|
|
|
(sx->lock_object.lo_flags & SX_ADAPTIVESPIN)) {
|
|
|
|
x = SX_OWNER(x);
|
|
|
|
owner = (struct thread *)x;
|
|
|
|
if (TD_IS_RUNNING(owner)) {
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR3(KTR_LOCK,
|
|
|
|
"%s: spinning on %p held by %p",
|
|
|
|
__func__, sx, owner);
|
|
|
|
GIANT_SAVE();
|
|
|
|
while (SX_OWNER(sx->sx_lock) == x &&
|
|
|
|
TD_IS_RUNNING(owner))
|
|
|
|
cpu_spinwait();
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#endif
|
2001-03-05 19:59:41 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
sleepq_lock(&sx->lock_object);
|
|
|
|
x = sx->sx_lock;
|
Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
2001-03-28 09:03:24 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* If the lock was released while spinning on the
|
|
|
|
* sleep queue chain lock, try again.
|
|
|
|
*/
|
|
|
|
if (x == SX_LOCK_UNLOCKED) {
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef ADAPTIVE_SX
|
|
|
|
/*
|
|
|
|
* The current lock owner might have started executing
|
|
|
|
* on another CPU (or the lock could have changed
|
|
|
|
* owners) while we were waiting on the sleep queue
|
|
|
|
* chain lock. If so, drop the sleep queue lock and try
|
|
|
|
* again.
|
|
|
|
*/
|
|
|
|
if (!(x & SX_LOCK_SHARED) &&
|
|
|
|
(sx->lock_object.lo_flags & SX_ADAPTIVESPIN)) {
|
|
|
|
owner = (struct thread *)SX_OWNER(x);
|
|
|
|
if (TD_IS_RUNNING(owner)) {
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If an exclusive lock was released with both shared
|
|
|
|
* and exclusive waiters and a shared waiter hasn't
|
|
|
|
* woken up and acquired the lock yet, sx_lock will be
|
|
|
|
* set to SX_LOCK_UNLOCKED | SX_LOCK_EXCLUSIVE_WAITERS.
|
|
|
|
* If we see that value, try to acquire it once. Note
|
|
|
|
* that we have to preserve SX_LOCK_EXCLUSIVE_WAITERS
|
|
|
|
* as there are other exclusive waiters still. If we
|
|
|
|
* fail, restart the loop.
|
|
|
|
*/
|
|
|
|
if (x == (SX_LOCK_UNLOCKED | SX_LOCK_EXCLUSIVE_WAITERS)) {
|
|
|
|
if (atomic_cmpset_acq_ptr(&sx->sx_lock,
|
|
|
|
SX_LOCK_UNLOCKED | SX_LOCK_EXCLUSIVE_WAITERS,
|
|
|
|
tid | SX_LOCK_EXCLUSIVE_WAITERS)) {
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
CTR2(KTR_LOCK, "%s: %p claimed by new writer",
|
|
|
|
__func__, sx);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Try to set the SX_LOCK_EXCLUSIVE_WAITERS. If we fail,
|
|
|
|
* than loop back and retry.
|
|
|
|
*/
|
|
|
|
if (!(x & SX_LOCK_EXCLUSIVE_WAITERS)) {
|
|
|
|
if (!atomic_cmpset_ptr(&sx->sx_lock, x,
|
|
|
|
x | SX_LOCK_EXCLUSIVE_WAITERS)) {
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p set excl waiters flag",
|
|
|
|
__func__, sx);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Since we have been unable to acquire the exclusive
|
|
|
|
* lock and the exclusive waiters flag is set, we have
|
|
|
|
* to sleep.
|
|
|
|
*/
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p blocking on sleep queue",
|
|
|
|
__func__, sx);
|
|
|
|
|
|
|
|
GIANT_SAVE();
|
|
|
|
sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name,
|
2007-05-31 09:14:48 +00:00
|
|
|
SLEEPQ_SX | ((opts & SX_INTERRUPTIBLE) ?
|
|
|
|
SLEEPQ_INTERRUPTIBLE : 0), SQ_EXCLUSIVE_QUEUE);
|
|
|
|
if (!(opts & SX_INTERRUPTIBLE))
|
2008-03-12 06:31:06 +00:00
|
|
|
sleepq_wait(&sx->lock_object, 0);
|
2007-05-31 09:14:48 +00:00
|
|
|
else
|
2008-03-12 06:31:06 +00:00
|
|
|
error = sleepq_wait_sig(&sx->lock_object, 0);
|
2007-03-31 23:23:42 +00:00
|
|
|
|
2007-05-31 09:14:48 +00:00
|
|
|
if (error) {
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK,
|
|
|
|
"%s: interruptible sleep by %p suspended by signal",
|
|
|
|
__func__, sx);
|
|
|
|
break;
|
|
|
|
}
|
2007-03-31 23:23:42 +00:00
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p resuming from sleep queue",
|
|
|
|
__func__, sx);
|
|
|
|
}
|
2007-05-29 19:46:37 +00:00
|
|
|
|
2007-04-04 00:01:05 +00:00
|
|
|
GIANT_RESTORE();
|
2007-05-31 09:14:48 +00:00
|
|
|
if (!error)
|
2007-07-06 13:20:44 +00:00
|
|
|
lock_profile_obtain_lock_success(&sx->lock_object, contested,
|
|
|
|
waittime, file, line);
|
2007-05-31 09:14:48 +00:00
|
|
|
return (error);
|
2001-03-05 19:59:41 +00:00
|
|
|
}
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* This function represents the so-called 'hard case' for sx_xunlock
|
|
|
|
* operation. All 'easy case' failures are redirected to this. Note
|
|
|
|
* that ideally this would be a static function, but it needs to be
|
|
|
|
* accessible from at least sx.h.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
_sx_xunlock_hard(struct sx *sx, uintptr_t tid, const char *file, int line)
|
2001-08-13 21:25:30 +00:00
|
|
|
{
|
2007-03-31 23:23:42 +00:00
|
|
|
uintptr_t x;
|
|
|
|
int queue;
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
MPASS(!(sx->sx_lock & SX_LOCK_SHARED));
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/* If the lock is recursed, then unrecurse one level. */
|
|
|
|
if (sx_xlocked(sx) && sx_recursed(sx)) {
|
|
|
|
if ((--sx->sx_recurse) == 0)
|
|
|
|
atomic_clear_ptr(&sx->sx_lock, SX_LOCK_RECURSED);
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p unrecursing", __func__, sx);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
MPASS(sx->sx_lock & (SX_LOCK_SHARED_WAITERS |
|
|
|
|
SX_LOCK_EXCLUSIVE_WAITERS));
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p contested", __func__, sx);
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
sleepq_lock(&sx->lock_object);
|
|
|
|
x = SX_LOCK_UNLOCKED;
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* The wake up algorithm here is quite simple and probably not
|
|
|
|
* ideal. It gives precedence to shared waiters if they are
|
|
|
|
* present. For this condition, we have to preserve the
|
|
|
|
* state of the exclusive waiters flag.
|
|
|
|
*/
|
|
|
|
if (sx->sx_lock & SX_LOCK_SHARED_WAITERS) {
|
|
|
|
queue = SQ_SHARED_QUEUE;
|
|
|
|
x |= (sx->sx_lock & SX_LOCK_EXCLUSIVE_WAITERS);
|
|
|
|
} else
|
|
|
|
queue = SQ_EXCLUSIVE_QUEUE;
|
|
|
|
|
|
|
|
/* Wake up all the waiters for the specific queue. */
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR3(KTR_LOCK, "%s: %p waking up all threads on %s queue",
|
|
|
|
__func__, sx, queue == SQ_SHARED_QUEUE ? "shared" :
|
|
|
|
"exclusive");
|
|
|
|
atomic_store_rel_ptr(&sx->sx_lock, x);
|
2008-03-12 06:31:06 +00:00
|
|
|
sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0, queue);
|
|
|
|
sleepq_release(&sx->lock_object);
|
2007-03-31 23:23:42 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This function represents the so-called 'hard case' for sx_slock
|
|
|
|
* operation. All 'easy case' failures are redirected to this. Note
|
|
|
|
* that ideally this would be a static function, but it needs to be
|
|
|
|
* accessible from at least sx.h.
|
|
|
|
*/
|
2007-05-31 09:14:48 +00:00
|
|
|
int
|
|
|
|
_sx_slock_hard(struct sx *sx, int opts, const char *file, int line)
|
2007-03-31 23:23:42 +00:00
|
|
|
{
|
|
|
|
GIANT_DECLARE;
|
|
|
|
#ifdef ADAPTIVE_SX
|
|
|
|
volatile struct thread *owner;
|
2007-07-06 13:20:44 +00:00
|
|
|
#endif
|
|
|
|
uint64_t waittime = 0;
|
|
|
|
int contested = 0;
|
2007-03-31 23:23:42 +00:00
|
|
|
uintptr_t x;
|
2007-07-06 13:20:44 +00:00
|
|
|
int error = 0;
|
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* As with rwlocks, we don't make any attempt to try to block
|
|
|
|
* shared locks once there is an exclusive waiter.
|
|
|
|
*/
|
|
|
|
for (;;) {
|
|
|
|
x = sx->sx_lock;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If no other thread has an exclusive lock then try to bump up
|
|
|
|
* the count of sharers. Since we have to preserve the state
|
|
|
|
* of SX_LOCK_EXCLUSIVE_WAITERS, if we fail to acquire the
|
|
|
|
* shared lock loop back and retry.
|
|
|
|
*/
|
|
|
|
if (x & SX_LOCK_SHARED) {
|
|
|
|
MPASS(!(x & SX_LOCK_SHARED_WAITERS));
|
|
|
|
if (atomic_cmpset_acq_ptr(&sx->sx_lock, x,
|
|
|
|
x + SX_ONE_SHARER)) {
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR4(KTR_LOCK,
|
|
|
|
"%s: %p succeed %p -> %p", __func__,
|
|
|
|
sx, (void *)x,
|
|
|
|
(void *)(x + SX_ONE_SHARER));
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
continue;
|
|
|
|
}
|
2007-12-15 23:13:31 +00:00
|
|
|
lock_profile_obtain_lock_failed(&sx->lock_object, &contested,
|
|
|
|
&waittime);
|
2007-03-31 23:23:42 +00:00
|
|
|
|
|
|
|
#ifdef ADAPTIVE_SX
|
|
|
|
/*
|
|
|
|
* If the owner is running on another CPU, spin until
|
|
|
|
* the owner stops running or the state of the lock
|
|
|
|
* changes.
|
|
|
|
*/
|
2007-12-15 23:13:31 +00:00
|
|
|
if (sx->lock_object.lo_flags & SX_ADAPTIVESPIN) {
|
2007-03-31 23:23:42 +00:00
|
|
|
x = SX_OWNER(x);
|
|
|
|
owner = (struct thread *)x;
|
|
|
|
if (TD_IS_RUNNING(owner)) {
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR3(KTR_LOCK,
|
|
|
|
"%s: spinning on %p held by %p",
|
|
|
|
__func__, sx, owner);
|
|
|
|
GIANT_SAVE();
|
|
|
|
while (SX_OWNER(sx->sx_lock) == x &&
|
|
|
|
TD_IS_RUNNING(owner))
|
|
|
|
cpu_spinwait();
|
|
|
|
continue;
|
|
|
|
}
|
2007-07-06 13:20:44 +00:00
|
|
|
}
|
2007-03-31 23:23:42 +00:00
|
|
|
#endif
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Some other thread already has an exclusive lock, so
|
|
|
|
* start the process of blocking.
|
|
|
|
*/
|
|
|
|
sleepq_lock(&sx->lock_object);
|
|
|
|
x = sx->sx_lock;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The lock could have been released while we spun.
|
|
|
|
* In this case loop back and retry.
|
|
|
|
*/
|
|
|
|
if (x & SX_LOCK_SHARED) {
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef ADAPTIVE_SX
|
|
|
|
/*
|
|
|
|
* If the owner is running on another CPU, spin until
|
|
|
|
* the owner stops running or the state of the lock
|
|
|
|
* changes.
|
|
|
|
*/
|
|
|
|
if (!(x & SX_LOCK_SHARED) &&
|
|
|
|
(sx->lock_object.lo_flags & SX_ADAPTIVESPIN)) {
|
|
|
|
owner = (struct thread *)SX_OWNER(x);
|
|
|
|
if (TD_IS_RUNNING(owner)) {
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Try to set the SX_LOCK_SHARED_WAITERS flag. If we
|
|
|
|
* fail to set it drop the sleep queue lock and loop
|
|
|
|
* back.
|
|
|
|
*/
|
|
|
|
if (!(x & SX_LOCK_SHARED_WAITERS)) {
|
|
|
|
if (!atomic_cmpset_ptr(&sx->sx_lock, x,
|
|
|
|
x | SX_LOCK_SHARED_WAITERS)) {
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p set shared waiters flag",
|
|
|
|
__func__, sx);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Since we have been unable to acquire the shared lock,
|
|
|
|
* we have to sleep.
|
|
|
|
*/
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p blocking on sleep queue",
|
|
|
|
__func__, sx);
|
2007-07-06 13:20:44 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
GIANT_SAVE();
|
|
|
|
sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name,
|
2007-05-31 09:14:48 +00:00
|
|
|
SLEEPQ_SX | ((opts & SX_INTERRUPTIBLE) ?
|
|
|
|
SLEEPQ_INTERRUPTIBLE : 0), SQ_SHARED_QUEUE);
|
|
|
|
if (!(opts & SX_INTERRUPTIBLE))
|
2008-03-12 06:31:06 +00:00
|
|
|
sleepq_wait(&sx->lock_object, 0);
|
2007-05-31 09:14:48 +00:00
|
|
|
else
|
2008-03-12 06:31:06 +00:00
|
|
|
error = sleepq_wait_sig(&sx->lock_object, 0);
|
2007-03-31 23:23:42 +00:00
|
|
|
|
2007-05-31 09:14:48 +00:00
|
|
|
if (error) {
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK,
|
|
|
|
"%s: interruptible sleep by %p suspended by signal",
|
|
|
|
__func__, sx);
|
|
|
|
break;
|
|
|
|
}
|
2007-03-31 23:23:42 +00:00
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p resuming from sleep queue",
|
|
|
|
__func__, sx);
|
2001-08-13 21:25:30 +00:00
|
|
|
}
|
2007-12-15 23:13:31 +00:00
|
|
|
if (error == 0)
|
|
|
|
lock_profile_obtain_lock_success(&sx->lock_object, contested,
|
|
|
|
waittime, file, line);
|
2007-03-31 23:23:42 +00:00
|
|
|
|
|
|
|
GIANT_RESTORE();
|
2007-05-31 09:14:48 +00:00
|
|
|
return (error);
|
2001-08-13 21:25:30 +00:00
|
|
|
}
|
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* This function represents the so-called 'hard case' for sx_sunlock
|
|
|
|
* operation. All 'easy case' failures are redirected to this. Note
|
|
|
|
* that ideally this would be a static function, but it needs to be
|
|
|
|
* accessible from at least sx.h.
|
|
|
|
*/
|
2001-08-13 21:25:30 +00:00
|
|
|
void
|
2007-03-31 23:23:42 +00:00
|
|
|
_sx_sunlock_hard(struct sx *sx, const char *file, int line)
|
2001-08-13 21:25:30 +00:00
|
|
|
{
|
2007-03-31 23:23:42 +00:00
|
|
|
uintptr_t x;
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
for (;;) {
|
|
|
|
x = sx->sx_lock;
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* We should never have sharers while at least one thread
|
|
|
|
* holds a shared lock.
|
|
|
|
*/
|
|
|
|
KASSERT(!(x & SX_LOCK_SHARED_WAITERS),
|
|
|
|
("%s: waiting sharers", __func__));
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* See if there is more than one shared lock held. If
|
|
|
|
* so, just drop one and return.
|
|
|
|
*/
|
|
|
|
if (SX_SHARERS(x) > 1) {
|
|
|
|
if (atomic_cmpset_ptr(&sx->sx_lock, x,
|
|
|
|
x - SX_ONE_SHARER)) {
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR4(KTR_LOCK,
|
|
|
|
"%s: %p succeeded %p -> %p",
|
|
|
|
__func__, sx, (void *)x,
|
|
|
|
(void *)(x - SX_ONE_SHARER));
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
continue;
|
|
|
|
}
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* If there aren't any waiters for an exclusive lock,
|
|
|
|
* then try to drop it quickly.
|
|
|
|
*/
|
|
|
|
if (!(x & SX_LOCK_EXCLUSIVE_WAITERS)) {
|
|
|
|
MPASS(x == SX_SHARERS_LOCK(1));
|
|
|
|
if (atomic_cmpset_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1),
|
|
|
|
SX_LOCK_UNLOCKED)) {
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p last succeeded",
|
|
|
|
__func__, sx);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* At this point, there should just be one sharer with
|
|
|
|
* exclusive waiters.
|
|
|
|
*/
|
|
|
|
MPASS(x == (SX_SHARERS_LOCK(1) | SX_LOCK_EXCLUSIVE_WAITERS));
|
2001-08-13 21:25:30 +00:00
|
|
|
|
2007-03-31 23:23:42 +00:00
|
|
|
sleepq_lock(&sx->lock_object);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Wake up semantic here is quite simple:
|
|
|
|
* Just wake up all the exclusive waiters.
|
|
|
|
* Note that the state of the lock could have changed,
|
|
|
|
* so if it fails loop back and retry.
|
|
|
|
*/
|
|
|
|
if (!atomic_cmpset_ptr(&sx->sx_lock,
|
|
|
|
SX_SHARERS_LOCK(1) | SX_LOCK_EXCLUSIVE_WAITERS,
|
|
|
|
SX_LOCK_UNLOCKED)) {
|
|
|
|
sleepq_release(&sx->lock_object);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
if (LOCK_LOG_TEST(&sx->lock_object, 0))
|
|
|
|
CTR2(KTR_LOCK, "%s: %p waking up all thread on"
|
|
|
|
"exclusive queue", __func__, sx);
|
2008-03-12 06:31:06 +00:00
|
|
|
sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0,
|
2007-03-31 23:23:42 +00:00
|
|
|
SQ_EXCLUSIVE_QUEUE);
|
2008-03-12 06:31:06 +00:00
|
|
|
sleepq_release(&sx->lock_object);
|
2007-03-31 23:23:42 +00:00
|
|
|
break;
|
|
|
|
}
|
2001-08-13 21:25:30 +00:00
|
|
|
}
|
2001-10-23 22:39:11 +00:00
|
|
|
|
|
|
|
#ifdef INVARIANT_SUPPORT
|
2001-10-24 14:18:33 +00:00
|
|
|
#ifndef INVARIANTS
|
|
|
|
#undef _sx_assert
|
|
|
|
#endif
|
|
|
|
|
2001-10-23 22:39:11 +00:00
|
|
|
/*
|
|
|
|
* In the non-WITNESS case, sx_assert() can only detect that at least
|
|
|
|
* *some* thread owns an slock, but it cannot guarantee that *this*
|
|
|
|
* thread owns an slock.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
_sx_assert(struct sx *sx, int what, const char *file, int line)
|
|
|
|
{
|
2007-03-31 23:23:42 +00:00
|
|
|
#ifndef WITNESS
|
|
|
|
int slocked = 0;
|
|
|
|
#endif
|
2001-10-23 22:39:11 +00:00
|
|
|
|
2004-02-27 16:13:44 +00:00
|
|
|
if (panicstr != NULL)
|
|
|
|
return;
|
2001-10-23 22:39:11 +00:00
|
|
|
switch (what) {
|
2007-05-19 21:26:05 +00:00
|
|
|
case SA_SLOCKED:
|
|
|
|
case SA_SLOCKED | SA_NOTRECURSED:
|
|
|
|
case SA_SLOCKED | SA_RECURSED:
|
2007-03-31 23:23:42 +00:00
|
|
|
#ifndef WITNESS
|
|
|
|
slocked = 1;
|
|
|
|
/* FALLTHROUGH */
|
|
|
|
#endif
|
2007-05-19 21:26:05 +00:00
|
|
|
case SA_LOCKED:
|
|
|
|
case SA_LOCKED | SA_NOTRECURSED:
|
|
|
|
case SA_LOCKED | SA_RECURSED:
|
2001-10-23 22:39:11 +00:00
|
|
|
#ifdef WITNESS
|
2007-03-21 21:20:51 +00:00
|
|
|
witness_assert(&sx->lock_object, what, file, line);
|
2001-10-23 22:39:11 +00:00
|
|
|
#else
|
2007-03-31 23:23:42 +00:00
|
|
|
/*
|
|
|
|
* If some other thread has an exclusive lock or we
|
|
|
|
* have one and are asserting a shared lock, fail.
|
|
|
|
* Also, if no one has a lock at all, fail.
|
|
|
|
*/
|
|
|
|
if (sx->sx_lock == SX_LOCK_UNLOCKED ||
|
|
|
|
(!(sx->sx_lock & SX_LOCK_SHARED) && (slocked ||
|
|
|
|
sx_xholder(sx) != curthread)))
|
2004-02-27 16:13:44 +00:00
|
|
|
panic("Lock %s not %slocked @ %s:%d\n",
|
2007-03-31 23:23:42 +00:00
|
|
|
sx->lock_object.lo_name, slocked ? "share " : "",
|
|
|
|
file, line);
|
|
|
|
|
|
|
|
if (!(sx->sx_lock & SX_LOCK_SHARED)) {
|
|
|
|
if (sx_recursed(sx)) {
|
2007-05-19 21:26:05 +00:00
|
|
|
if (what & SA_NOTRECURSED)
|
2007-03-31 23:23:42 +00:00
|
|
|
panic("Lock %s recursed @ %s:%d\n",
|
|
|
|
sx->lock_object.lo_name, file,
|
|
|
|
line);
|
2007-05-19 21:26:05 +00:00
|
|
|
} else if (what & SA_RECURSED)
|
2007-03-31 23:23:42 +00:00
|
|
|
panic("Lock %s not recursed @ %s:%d\n",
|
|
|
|
sx->lock_object.lo_name, file, line);
|
|
|
|
}
|
2001-10-23 22:39:11 +00:00
|
|
|
#endif
|
|
|
|
break;
|
2007-05-19 21:26:05 +00:00
|
|
|
case SA_XLOCKED:
|
|
|
|
case SA_XLOCKED | SA_NOTRECURSED:
|
|
|
|
case SA_XLOCKED | SA_RECURSED:
|
2007-03-31 23:23:42 +00:00
|
|
|
if (sx_xholder(sx) != curthread)
|
2004-02-27 16:13:44 +00:00
|
|
|
panic("Lock %s not exclusively locked @ %s:%d\n",
|
2007-03-21 21:20:51 +00:00
|
|
|
sx->lock_object.lo_name, file, line);
|
2007-03-31 23:23:42 +00:00
|
|
|
if (sx_recursed(sx)) {
|
2007-05-19 21:26:05 +00:00
|
|
|
if (what & SA_NOTRECURSED)
|
2007-03-31 23:23:42 +00:00
|
|
|
panic("Lock %s recursed @ %s:%d\n",
|
|
|
|
sx->lock_object.lo_name, file, line);
|
2007-05-19 21:26:05 +00:00
|
|
|
} else if (what & SA_RECURSED)
|
2007-03-31 23:23:42 +00:00
|
|
|
panic("Lock %s not recursed @ %s:%d\n",
|
|
|
|
sx->lock_object.lo_name, file, line);
|
2001-10-23 22:39:11 +00:00
|
|
|
break;
|
2007-05-19 21:26:05 +00:00
|
|
|
case SA_UNLOCKED:
|
2004-02-04 08:14:58 +00:00
|
|
|
#ifdef WITNESS
|
2007-03-21 21:20:51 +00:00
|
|
|
witness_assert(&sx->lock_object, what, file, line);
|
2004-02-04 08:14:58 +00:00
|
|
|
#else
|
2004-02-19 14:19:31 +00:00
|
|
|
/*
|
2007-03-31 23:23:42 +00:00
|
|
|
* If we hold an exclusve lock fail. We can't
|
|
|
|
* reliably check to see if we hold a shared lock or
|
|
|
|
* not.
|
2004-02-19 14:19:31 +00:00
|
|
|
*/
|
2007-03-31 23:23:42 +00:00
|
|
|
if (sx_xholder(sx) == curthread)
|
2004-02-27 16:13:44 +00:00
|
|
|
panic("Lock %s exclusively locked @ %s:%d\n",
|
2007-03-21 21:20:51 +00:00
|
|
|
sx->lock_object.lo_name, file, line);
|
2004-02-04 08:14:58 +00:00
|
|
|
#endif
|
|
|
|
break;
|
2001-10-23 22:39:11 +00:00
|
|
|
default:
|
|
|
|
panic("Unknown sx lock assertion: %d @ %s:%d", what, file,
|
|
|
|
line);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#endif /* INVARIANT_SUPPORT */
|
2005-12-13 23:14:35 +00:00
|
|
|
|
|
|
|
#ifdef DDB
|
2007-03-31 23:23:42 +00:00
|
|
|
static void
|
2005-12-13 23:14:35 +00:00
|
|
|
db_show_sx(struct lock_object *lock)
|
|
|
|
{
|
|
|
|
struct thread *td;
|
|
|
|
struct sx *sx;
|
|
|
|
|
|
|
|
sx = (struct sx *)lock;
|
|
|
|
|
|
|
|
db_printf(" state: ");
|
2007-03-31 23:23:42 +00:00
|
|
|
if (sx->sx_lock == SX_LOCK_UNLOCKED)
|
|
|
|
db_printf("UNLOCKED\n");
|
2007-05-08 21:51:37 +00:00
|
|
|
else if (sx->sx_lock == SX_LOCK_DESTROYED) {
|
|
|
|
db_printf("DESTROYED\n");
|
|
|
|
return;
|
|
|
|
} else if (sx->sx_lock & SX_LOCK_SHARED)
|
2007-03-31 23:23:42 +00:00
|
|
|
db_printf("SLOCK: %ju\n", (uintmax_t)SX_SHARERS(sx->sx_lock));
|
|
|
|
else {
|
|
|
|
td = sx_xholder(sx);
|
2005-12-13 23:14:35 +00:00
|
|
|
db_printf("XLOCK: %p (tid %d, pid %d, \"%s\")\n", td,
|
2007-11-14 06:21:24 +00:00
|
|
|
td->td_tid, td->td_proc->p_pid, td->td_name);
|
2007-03-31 23:23:42 +00:00
|
|
|
if (sx_recursed(sx))
|
|
|
|
db_printf(" recursed: %d\n", sx->sx_recurse);
|
|
|
|
}
|
|
|
|
|
|
|
|
db_printf(" waiters: ");
|
|
|
|
switch(sx->sx_lock &
|
|
|
|
(SX_LOCK_SHARED_WAITERS | SX_LOCK_EXCLUSIVE_WAITERS)) {
|
|
|
|
case SX_LOCK_SHARED_WAITERS:
|
|
|
|
db_printf("shared\n");
|
|
|
|
break;
|
|
|
|
case SX_LOCK_EXCLUSIVE_WAITERS:
|
|
|
|
db_printf("exclusive\n");
|
|
|
|
break;
|
|
|
|
case SX_LOCK_SHARED_WAITERS | SX_LOCK_EXCLUSIVE_WAITERS:
|
|
|
|
db_printf("exclusive and shared\n");
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
db_printf("none\n");
|
|
|
|
}
|
2005-12-13 23:14:35 +00:00
|
|
|
}
|
2006-08-15 18:29:01 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Check to see if a thread that is blocked on a sleep queue is actually
|
|
|
|
* blocked on an sx lock. If so, output some details and return true.
|
|
|
|
* If the lock has an exclusive owner, return that in *ownerp.
|
|
|
|
*/
|
|
|
|
int
|
|
|
|
sx_chain(struct thread *td, struct thread **ownerp)
|
|
|
|
{
|
|
|
|
struct sx *sx;
|
|
|
|
|
|
|
|
/*
|
2007-03-31 23:23:42 +00:00
|
|
|
* Check to see if this thread is blocked on an sx lock.
|
|
|
|
* First, we check the lock class. If that is ok, then we
|
|
|
|
* compare the lock name against the wait message.
|
2006-08-15 18:29:01 +00:00
|
|
|
*/
|
2007-03-31 23:23:42 +00:00
|
|
|
sx = td->td_wchan;
|
|
|
|
if (LOCK_CLASS(&sx->lock_object) != &lock_class_sx ||
|
|
|
|
sx->lock_object.lo_name != td->td_wmesg)
|
2006-08-15 18:29:01 +00:00
|
|
|
return (0);
|
|
|
|
|
|
|
|
/* We think we have an sx lock, so output some details. */
|
|
|
|
db_printf("blocked on sx \"%s\" ", td->td_wmesg);
|
2007-03-31 23:23:42 +00:00
|
|
|
*ownerp = sx_xholder(sx);
|
|
|
|
if (sx->sx_lock & SX_LOCK_SHARED)
|
|
|
|
db_printf("SLOCK (count %ju)\n",
|
|
|
|
(uintmax_t)SX_SHARERS(sx->sx_lock));
|
|
|
|
else
|
2006-08-15 18:29:01 +00:00
|
|
|
db_printf("XLOCK\n");
|
|
|
|
return (1);
|
|
|
|
}
|
2005-12-13 23:14:35 +00:00
|
|
|
#endif
|