2001-01-16 01:00:43 +00:00
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/*-
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* Copyright (c) 2000 Jake Burkholder <jake@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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2003-06-11 00:56:59 +00:00
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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2001-01-16 01:00:43 +00:00
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#include "opt_ktrace.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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2001-05-01 08:13:21 +00:00
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#include <sys/lock.h>
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#include <sys/mutex.h>
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2001-01-16 01:00:43 +00:00
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#include <sys/proc.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/condvar.h>
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2003-01-26 04:00:39 +00:00
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#include <sys/sched.h>
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2001-01-16 01:00:43 +00:00
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#include <sys/signalvar.h>
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Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
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#include <sys/sleepqueue.h>
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2001-01-16 01:00:43 +00:00
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#include <sys/resourcevar.h>
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#ifdef KTRACE
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#include <sys/uio.h>
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#include <sys/ktrace.h>
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#endif
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/*
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* Common sanity checks for cv_wait* functions.
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*/
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2001-09-12 08:38:13 +00:00
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#define CV_ASSERT(cvp, mp, td) do { \
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2001-12-10 05:51:45 +00:00
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KASSERT((td) != NULL, ("%s: curthread NULL", __func__)); \
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2002-09-11 08:13:56 +00:00
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KASSERT(TD_IS_RUNNING(td), ("%s: not TDS_RUNNING", __func__)); \
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2001-12-10 05:51:45 +00:00
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KASSERT((cvp) != NULL, ("%s: cvp NULL", __func__)); \
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KASSERT((mp) != NULL, ("%s: mp NULL", __func__)); \
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2001-01-16 01:00:43 +00:00
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mtx_assert((mp), MA_OWNED | MA_NOTRECURSED); \
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} while (0)
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/*
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* Initialize a condition variable. Must be called before use.
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*/
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void
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cv_init(struct cv *cvp, const char *desc)
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{
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cvp->cv_description = desc;
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2004-04-06 19:17:46 +00:00
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cvp->cv_waiters = 0;
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2001-01-16 01:00:43 +00:00
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}
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/*
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* Destroy a condition variable. The condition variable must be re-initialized
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* in order to be re-used.
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*/
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void
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cv_destroy(struct cv *cvp)
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{
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Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
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#ifdef INVARIANTS
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2004-10-12 18:36:20 +00:00
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struct sleepqueue *sq;
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2001-01-16 01:00:43 +00:00
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2004-10-12 18:36:20 +00:00
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sleepq_lock(cvp);
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Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
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sq = sleepq_lookup(cvp);
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sleepq_release(cvp);
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KASSERT(sq == NULL, ("%s: associated sleep queue non-empty", __func__));
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#endif
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2001-01-16 01:00:43 +00:00
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}
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/*
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2001-09-12 08:38:13 +00:00
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* Wait on a condition variable. The current thread is placed on the condition
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2001-01-16 01:00:43 +00:00
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* variable's wait queue and suspended. A cv_signal or cv_broadcast on the same
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2001-09-12 08:38:13 +00:00
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* condition variable will resume the thread. The mutex is released before
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2001-01-16 01:00:43 +00:00
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* sleeping and will be held on return. It is recommended that the mutex be
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* held when cv_signal or cv_broadcast are called.
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*/
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void
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cv_wait(struct cv *cvp, struct mtx *mp)
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{
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2001-09-12 08:38:13 +00:00
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struct thread *td;
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2001-01-16 01:00:43 +00:00
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WITNESS_SAVE_DECL(mp);
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2001-09-12 08:38:13 +00:00
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td = curthread;
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2001-01-16 01:00:43 +00:00
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#ifdef KTRACE
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2002-06-07 05:39:16 +00:00
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if (KTRPOINT(td, KTR_CSW))
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ktrcsw(1, 0);
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2001-01-16 01:00:43 +00:00
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#endif
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2001-09-12 08:38:13 +00:00
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CV_ASSERT(cvp, mp, td);
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2003-03-04 21:03:05 +00:00
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WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->mtx_object,
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"Waiting on \"%s\"", cvp->cv_description);
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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
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WITNESS_SAVE(&mp->mtx_object, mp);
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2001-01-16 01:00:43 +00:00
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Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
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if (cold || panicstr) {
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2001-01-16 01:00:43 +00:00
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/*
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2002-07-17 02:23:44 +00:00
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* During autoconfiguration, just give interrupts
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* a chance, then just return. Don't run any other
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* thread or panic below, in case this is the idle
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* process and already asleep.
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2001-01-16 01:00:43 +00:00
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*/
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return;
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}
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2002-04-23 19:50:22 +00:00
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2004-10-12 18:36:20 +00:00
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sleepq_lock(cvp);
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2001-01-16 01:00:43 +00:00
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2004-04-06 19:17:46 +00:00
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cvp->cv_waiters++;
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Change the preemption code for software interrupt thread schedules and
mutex releases to not require flags for the cases when preemption is
not allowed:
The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe. Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer. This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs. Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called. (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)
I've tested the changes to the interrupt code on i386 and alpha. I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine. PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken. Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.
Reviewed by: peter
Tested on: i386, alpha
2002-01-05 08:47:13 +00:00
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DROP_GIANT();
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mtx_unlock(mp);
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2001-01-16 01:00:43 +00:00
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2004-10-12 18:36:20 +00:00
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sleepq_add(cvp, mp, cvp->cv_description, SLEEPQ_CONDVAR);
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Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
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sleepq_wait(cvp);
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2001-01-16 01:00:43 +00:00
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#ifdef KTRACE
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2002-06-07 05:39:16 +00:00
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if (KTRPOINT(td, KTR_CSW))
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ktrcsw(0, 0);
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2001-01-16 01:00:43 +00:00
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#endif
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PICKUP_GIANT();
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Change and clean the mutex lock interface.
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
2001-02-09 06:11:45 +00:00
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mtx_lock(mp);
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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
|
|
|
WITNESS_RESTORE(&mp->mtx_object, mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Wait on a condition variable, allowing interruption by signals. Return 0 if
|
2001-09-12 08:38:13 +00:00
|
|
|
* the thread was resumed with cv_signal or cv_broadcast, EINTR or ERESTART if
|
2001-01-16 01:00:43 +00:00
|
|
|
* a signal was caught. If ERESTART is returned the system call should be
|
|
|
|
|
* restarted if possible.
|
|
|
|
|
*/
|
|
|
|
|
int
|
|
|
|
|
cv_wait_sig(struct cv *cvp, struct mtx *mp)
|
|
|
|
|
{
|
2001-09-12 08:38:13 +00:00
|
|
|
struct thread *td;
|
2001-09-19 02:53:59 +00:00
|
|
|
struct proc *p;
|
Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
|
|
|
int rval, sig;
|
2001-01-16 01:00:43 +00:00
|
|
|
WITNESS_SAVE_DECL(mp);
|
|
|
|
|
|
2001-09-12 08:38:13 +00:00
|
|
|
td = curthread;
|
2001-09-18 23:27:06 +00:00
|
|
|
p = td->td_proc;
|
2001-01-16 01:00:43 +00:00
|
|
|
#ifdef KTRACE
|
2002-06-07 05:39:16 +00:00
|
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
|
|
|
ktrcsw(1, 0);
|
2001-01-16 01:00:43 +00:00
|
|
|
#endif
|
2001-09-12 08:38:13 +00:00
|
|
|
CV_ASSERT(cvp, mp, td);
|
2003-03-04 21:03:05 +00:00
|
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->mtx_object,
|
|
|
|
|
"Waiting on \"%s\"", cvp->cv_description);
|
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
|
|
|
WITNESS_SAVE(&mp->mtx_object, mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
if (cold || panicstr) {
|
|
|
|
|
/*
|
|
|
|
|
* After a panic, or during autoconfiguration, just give
|
|
|
|
|
* interrupts a chance, then just return; don't run any other
|
|
|
|
|
* procs or panic below, in case this is the idle process and
|
|
|
|
|
* already asleep.
|
|
|
|
|
*/
|
2004-08-10 17:42:59 +00:00
|
|
|
return (0);
|
2001-01-16 01:00:43 +00:00
|
|
|
}
|
2002-04-23 19:50:22 +00:00
|
|
|
|
2004-10-12 18:36:20 +00:00
|
|
|
sleepq_lock(cvp);
|
2002-04-23 19:50:22 +00:00
|
|
|
|
2004-08-10 17:42:59 +00:00
|
|
|
/*
|
|
|
|
|
* Don't bother sleeping if we are exiting and not the exiting
|
|
|
|
|
* thread or if our thread is marked as interrupted.
|
|
|
|
|
*/
|
|
|
|
|
mtx_lock_spin(&sched_lock);
|
2004-08-19 11:31:42 +00:00
|
|
|
rval = thread_sleep_check(td);
|
2004-08-10 17:42:59 +00:00
|
|
|
mtx_unlock_spin(&sched_lock);
|
2004-08-19 11:31:42 +00:00
|
|
|
if (rval != 0) {
|
|
|
|
|
sleepq_release(cvp);
|
|
|
|
|
return (rval);
|
|
|
|
|
}
|
2001-01-16 01:00:43 +00:00
|
|
|
|
2004-04-06 19:17:46 +00:00
|
|
|
cvp->cv_waiters++;
|
Change the preemption code for software interrupt thread schedules and
mutex releases to not require flags for the cases when preemption is
not allowed:
The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe. Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer. This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs. Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called. (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)
I've tested the changes to the interrupt code on i386 and alpha. I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine. PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken. Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.
Reviewed by: peter
Tested on: i386, alpha
2002-01-05 08:47:13 +00:00
|
|
|
DROP_GIANT();
|
|
|
|
|
mtx_unlock(mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
2004-10-12 18:36:20 +00:00
|
|
|
sleepq_add(cvp, mp, cvp->cv_description, SLEEPQ_CONDVAR |
|
2004-08-19 11:31:42 +00:00
|
|
|
SLEEPQ_INTERRUPTIBLE);
|
Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
|
|
|
sig = sleepq_catch_signals(cvp);
|
2004-08-19 11:31:42 +00:00
|
|
|
rval = sleepq_wait_sig(cvp);
|
Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
|
|
|
if (rval == 0)
|
|
|
|
|
rval = sleepq_calc_signal_retval(sig);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
#ifdef KTRACE
|
2002-06-07 05:39:16 +00:00
|
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
|
|
|
ktrcsw(0, 0);
|
2001-01-16 01:00:43 +00:00
|
|
|
#endif
|
2002-06-07 05:39:16 +00:00
|
|
|
PICKUP_GIANT();
|
Change and clean the mutex lock interface.
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
2001-02-09 06:11:45 +00:00
|
|
|
mtx_lock(mp);
|
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
|
|
|
WITNESS_RESTORE(&mp->mtx_object, mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
return (rval);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Wait on a condition variable for at most timo/hz seconds. Returns 0 if the
|
|
|
|
|
* process was resumed by cv_signal or cv_broadcast, EWOULDBLOCK if the timeout
|
|
|
|
|
* expires.
|
|
|
|
|
*/
|
|
|
|
|
int
|
|
|
|
|
cv_timedwait(struct cv *cvp, struct mtx *mp, int timo)
|
|
|
|
|
{
|
2001-09-12 08:38:13 +00:00
|
|
|
struct thread *td;
|
2001-01-16 01:00:43 +00:00
|
|
|
int rval;
|
|
|
|
|
WITNESS_SAVE_DECL(mp);
|
|
|
|
|
|
2001-09-12 08:38:13 +00:00
|
|
|
td = curthread;
|
2001-01-16 01:00:43 +00:00
|
|
|
rval = 0;
|
|
|
|
|
#ifdef KTRACE
|
2002-06-07 05:39:16 +00:00
|
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
|
|
|
ktrcsw(1, 0);
|
2001-01-16 01:00:43 +00:00
|
|
|
#endif
|
2001-09-12 08:38:13 +00:00
|
|
|
CV_ASSERT(cvp, mp, td);
|
2003-03-04 21:03:05 +00:00
|
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->mtx_object,
|
|
|
|
|
"Waiting on \"%s\"", cvp->cv_description);
|
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
|
|
|
WITNESS_SAVE(&mp->mtx_object, mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
if (cold || panicstr) {
|
|
|
|
|
/*
|
|
|
|
|
* After a panic, or during autoconfiguration, just give
|
|
|
|
|
* interrupts a chance, then just return; don't run any other
|
2001-09-12 08:38:13 +00:00
|
|
|
* thread or panic below, in case this is the idle process and
|
2001-01-16 01:00:43 +00:00
|
|
|
* already asleep.
|
|
|
|
|
*/
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
2002-04-23 19:50:22 +00:00
|
|
|
|
2004-10-12 18:36:20 +00:00
|
|
|
sleepq_lock(cvp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
2004-04-06 19:17:46 +00:00
|
|
|
cvp->cv_waiters++;
|
Change the preemption code for software interrupt thread schedules and
mutex releases to not require flags for the cases when preemption is
not allowed:
The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe. Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer. This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs. Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called. (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)
I've tested the changes to the interrupt code on i386 and alpha. I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine. PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken. Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.
Reviewed by: peter
Tested on: i386, alpha
2002-01-05 08:47:13 +00:00
|
|
|
DROP_GIANT();
|
|
|
|
|
mtx_unlock(mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
2004-10-12 18:36:20 +00:00
|
|
|
sleepq_add(cvp, mp, cvp->cv_description, SLEEPQ_CONDVAR);
|
2004-03-12 19:06:18 +00:00
|
|
|
sleepq_set_timeout(cvp, timo);
|
2004-06-28 18:57:06 +00:00
|
|
|
rval = sleepq_timedwait(cvp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
#ifdef KTRACE
|
2002-06-07 05:39:16 +00:00
|
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
|
|
|
ktrcsw(0, 0);
|
2001-01-16 01:00:43 +00:00
|
|
|
#endif
|
|
|
|
|
PICKUP_GIANT();
|
Change and clean the mutex lock interface.
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
2001-02-09 06:11:45 +00:00
|
|
|
mtx_lock(mp);
|
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
|
|
|
WITNESS_RESTORE(&mp->mtx_object, mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
return (rval);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Wait on a condition variable for at most timo/hz seconds, allowing
|
2001-09-12 08:38:13 +00:00
|
|
|
* interruption by signals. Returns 0 if the thread was resumed by cv_signal
|
2001-01-16 01:00:43 +00:00
|
|
|
* or cv_broadcast, EWOULDBLOCK if the timeout expires, and EINTR or ERESTART if
|
|
|
|
|
* a signal was caught.
|
|
|
|
|
*/
|
|
|
|
|
int
|
|
|
|
|
cv_timedwait_sig(struct cv *cvp, struct mtx *mp, int timo)
|
|
|
|
|
{
|
2001-09-12 08:38:13 +00:00
|
|
|
struct thread *td;
|
2001-09-18 23:27:06 +00:00
|
|
|
struct proc *p;
|
2001-01-16 01:00:43 +00:00
|
|
|
int rval;
|
|
|
|
|
int sig;
|
|
|
|
|
WITNESS_SAVE_DECL(mp);
|
|
|
|
|
|
2001-09-12 08:38:13 +00:00
|
|
|
td = curthread;
|
2001-09-18 23:27:06 +00:00
|
|
|
p = td->td_proc;
|
2001-01-16 01:00:43 +00:00
|
|
|
rval = 0;
|
|
|
|
|
#ifdef KTRACE
|
2002-06-07 05:39:16 +00:00
|
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
|
|
|
ktrcsw(1, 0);
|
2001-01-16 01:00:43 +00:00
|
|
|
#endif
|
2001-09-12 08:38:13 +00:00
|
|
|
CV_ASSERT(cvp, mp, td);
|
2003-03-04 21:03:05 +00:00
|
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->mtx_object,
|
|
|
|
|
"Waiting on \"%s\"", cvp->cv_description);
|
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
|
|
|
WITNESS_SAVE(&mp->mtx_object, mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
if (cold || panicstr) {
|
|
|
|
|
/*
|
|
|
|
|
* After a panic, or during autoconfiguration, just give
|
|
|
|
|
* interrupts a chance, then just return; don't run any other
|
2001-09-12 08:38:13 +00:00
|
|
|
* thread or panic below, in case this is the idle process and
|
2001-01-16 01:00:43 +00:00
|
|
|
* already asleep.
|
|
|
|
|
*/
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
2002-04-23 19:50:22 +00:00
|
|
|
|
2004-10-12 18:36:20 +00:00
|
|
|
sleepq_lock(cvp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
2004-08-10 17:42:59 +00:00
|
|
|
/*
|
|
|
|
|
* Don't bother sleeping if we are exiting and not the exiting
|
|
|
|
|
* thread or if our thread is marked as interrupted.
|
|
|
|
|
*/
|
|
|
|
|
mtx_lock_spin(&sched_lock);
|
2004-08-19 11:31:42 +00:00
|
|
|
rval = thread_sleep_check(td);
|
2004-08-10 17:42:59 +00:00
|
|
|
mtx_unlock_spin(&sched_lock);
|
2004-08-19 11:31:42 +00:00
|
|
|
if (rval != 0) {
|
|
|
|
|
sleepq_release(cvp);
|
|
|
|
|
return (rval);
|
|
|
|
|
}
|
2004-08-10 17:42:59 +00:00
|
|
|
|
2004-04-06 19:17:46 +00:00
|
|
|
cvp->cv_waiters++;
|
Change the preemption code for software interrupt thread schedules and
mutex releases to not require flags for the cases when preemption is
not allowed:
The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe. Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer. This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs. Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called. (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)
I've tested the changes to the interrupt code on i386 and alpha. I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine. PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken. Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.
Reviewed by: peter
Tested on: i386, alpha
2002-01-05 08:47:13 +00:00
|
|
|
DROP_GIANT();
|
|
|
|
|
mtx_unlock(mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
2004-10-12 18:36:20 +00:00
|
|
|
sleepq_add(cvp, mp, cvp->cv_description, SLEEPQ_CONDVAR |
|
2004-08-19 11:31:42 +00:00
|
|
|
SLEEPQ_INTERRUPTIBLE);
|
2004-03-12 19:06:18 +00:00
|
|
|
sleepq_set_timeout(cvp, timo);
|
Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
|
|
|
sig = sleepq_catch_signals(cvp);
|
2004-08-19 11:31:42 +00:00
|
|
|
rval = sleepq_timedwait_sig(cvp, sig != 0);
|
Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
|
|
|
if (rval == 0)
|
|
|
|
|
rval = sleepq_calc_signal_retval(sig);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
#ifdef KTRACE
|
2002-06-07 05:39:16 +00:00
|
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
|
|
|
ktrcsw(0, 0);
|
2001-01-16 01:00:43 +00:00
|
|
|
#endif
|
2002-06-07 05:39:16 +00:00
|
|
|
PICKUP_GIANT();
|
Change and clean the mutex lock interface.
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
2001-02-09 06:11:45 +00:00
|
|
|
mtx_lock(mp);
|
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
|
|
|
WITNESS_RESTORE(&mp->mtx_object, mp);
|
2001-01-16 01:00:43 +00:00
|
|
|
|
|
|
|
|
return (rval);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
2001-09-12 08:38:13 +00:00
|
|
|
* Signal a condition variable, wakes up one waiting thread. Will also wakeup
|
2001-01-16 01:00:43 +00:00
|
|
|
* the swapper if the process is not in memory, so that it can bring the
|
2001-09-12 08:38:13 +00:00
|
|
|
* sleeping process in. Note that this may also result in additional threads
|
2001-01-16 01:00:43 +00:00
|
|
|
* being made runnable. Should be called with the same mutex as was passed to
|
|
|
|
|
* cv_wait held.
|
|
|
|
|
*/
|
|
|
|
|
void
|
|
|
|
|
cv_signal(struct cv *cvp)
|
|
|
|
|
{
|
|
|
|
|
|
2004-10-12 18:36:20 +00:00
|
|
|
sleepq_lock(cvp);
|
2004-04-06 19:17:46 +00:00
|
|
|
if (cvp->cv_waiters > 0) {
|
|
|
|
|
cvp->cv_waiters--;
|
|
|
|
|
sleepq_signal(cvp, SLEEPQ_CONDVAR, -1);
|
2004-10-12 18:36:20 +00:00
|
|
|
} else
|
|
|
|
|
sleepq_release(cvp);
|
2001-01-16 01:00:43 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
2001-09-12 08:38:13 +00:00
|
|
|
* Broadcast a signal to a condition variable. Wakes up all waiting threads.
|
2001-01-16 01:00:43 +00:00
|
|
|
* Should be called with the same mutex as was passed to cv_wait held.
|
|
|
|
|
*/
|
|
|
|
|
void
|
2003-11-09 09:17:26 +00:00
|
|
|
cv_broadcastpri(struct cv *cvp, int pri)
|
2001-01-16 01:00:43 +00:00
|
|
|
{
|
|
|
|
|
|
2004-10-12 18:36:20 +00:00
|
|
|
sleepq_lock(cvp);
|
2004-04-06 19:17:46 +00:00
|
|
|
if (cvp->cv_waiters > 0) {
|
|
|
|
|
cvp->cv_waiters = 0;
|
|
|
|
|
sleepq_broadcast(cvp, SLEEPQ_CONDVAR, pri);
|
2004-10-12 18:36:20 +00:00
|
|
|
} else
|
|
|
|
|
sleepq_release(cvp);
|
2001-01-16 01:00:43 +00:00
|
|
|
}
|
