44f3b09204
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.
357 lines
8.9 KiB
C
357 lines
8.9 KiB
C
/*-
|
|
* Copyright (c) 2000 Jake Burkholder <jake@freebsd.org>.
|
|
* All rights reserved.
|
|
*
|
|
* 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, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, 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 AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include "opt_ktrace.h"
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/ktr.h>
|
|
#include <sys/condvar.h>
|
|
#include <sys/sched.h>
|
|
#include <sys/signalvar.h>
|
|
#include <sys/sleepqueue.h>
|
|
#include <sys/resourcevar.h>
|
|
#ifdef KTRACE
|
|
#include <sys/uio.h>
|
|
#include <sys/ktrace.h>
|
|
#endif
|
|
|
|
/*
|
|
* Common sanity checks for cv_wait* functions.
|
|
*/
|
|
#define CV_ASSERT(cvp, mp, td) do { \
|
|
KASSERT((td) != NULL, ("%s: curthread NULL", __func__)); \
|
|
KASSERT(TD_IS_RUNNING(td), ("%s: not TDS_RUNNING", __func__)); \
|
|
KASSERT((cvp) != NULL, ("%s: cvp NULL", __func__)); \
|
|
KASSERT((mp) != NULL, ("%s: mp NULL", __func__)); \
|
|
mtx_assert((mp), MA_OWNED | MA_NOTRECURSED); \
|
|
} while (0)
|
|
|
|
/*
|
|
* Initialize a condition variable. Must be called before use.
|
|
*/
|
|
void
|
|
cv_init(struct cv *cvp, const char *desc)
|
|
{
|
|
|
|
cvp->cv_description = desc;
|
|
}
|
|
|
|
/*
|
|
* Destroy a condition variable. The condition variable must be re-initialized
|
|
* in order to be re-used.
|
|
*/
|
|
void
|
|
cv_destroy(struct cv *cvp)
|
|
{
|
|
#ifdef INVARIANTS
|
|
struct sleepqueue *sq;
|
|
|
|
sq = sleepq_lookup(cvp);
|
|
sleepq_release(cvp);
|
|
KASSERT(sq == NULL, ("%s: associated sleep queue non-empty", __func__));
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Wait on a condition variable. The current thread is placed on the condition
|
|
* variable's wait queue and suspended. A cv_signal or cv_broadcast on the same
|
|
* condition variable will resume the thread. The mutex is released before
|
|
* sleeping and will be held on return. It is recommended that the mutex be
|
|
* held when cv_signal or cv_broadcast are called.
|
|
*/
|
|
void
|
|
cv_wait(struct cv *cvp, struct mtx *mp)
|
|
{
|
|
struct sleepqueue *sq;
|
|
struct thread *td;
|
|
WITNESS_SAVE_DECL(mp);
|
|
|
|
td = curthread;
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(1, 0);
|
|
#endif
|
|
CV_ASSERT(cvp, mp, td);
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->mtx_object,
|
|
"Waiting on \"%s\"", cvp->cv_description);
|
|
WITNESS_SAVE(&mp->mtx_object, mp);
|
|
|
|
if (cold || panicstr) {
|
|
/*
|
|
* During autoconfiguration, just give interrupts
|
|
* a chance, then just return. Don't run any other
|
|
* thread or panic below, in case this is the idle
|
|
* process and already asleep.
|
|
*/
|
|
return;
|
|
}
|
|
|
|
sq = sleepq_lookup(cvp);
|
|
|
|
DROP_GIANT();
|
|
mtx_unlock(mp);
|
|
|
|
sleepq_add(sq, cvp, mp, cvp->cv_description, SLEEPQ_CONDVAR);
|
|
sleepq_wait(cvp);
|
|
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(0, 0);
|
|
#endif
|
|
PICKUP_GIANT();
|
|
mtx_lock(mp);
|
|
WITNESS_RESTORE(&mp->mtx_object, mp);
|
|
}
|
|
|
|
/*
|
|
* Wait on a condition variable, allowing interruption by signals. Return 0 if
|
|
* the thread was resumed with cv_signal or cv_broadcast, EINTR or ERESTART if
|
|
* 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)
|
|
{
|
|
struct sleepqueue *sq;
|
|
struct thread *td;
|
|
struct proc *p;
|
|
int rval, sig;
|
|
WITNESS_SAVE_DECL(mp);
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
rval = 0;
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(1, 0);
|
|
#endif
|
|
CV_ASSERT(cvp, mp, td);
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->mtx_object,
|
|
"Waiting on \"%s\"", cvp->cv_description);
|
|
WITNESS_SAVE(&mp->mtx_object, mp);
|
|
|
|
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.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
sq = sleepq_lookup(cvp);
|
|
|
|
/* XXX: Missing the threading checks from msleep! */
|
|
|
|
DROP_GIANT();
|
|
mtx_unlock(mp);
|
|
|
|
sleepq_add(sq, cvp, mp, cvp->cv_description, SLEEPQ_CONDVAR);
|
|
sig = sleepq_catch_signals(cvp);
|
|
/*
|
|
* XXX: Missing magic return value handling for no signal
|
|
* caught but thread woken up during check.
|
|
*/
|
|
rval = sleepq_wait_sig(cvp);
|
|
if (rval == 0)
|
|
rval = sleepq_calc_signal_retval(sig);
|
|
|
|
/* XXX: Part of missing threading checks? */
|
|
PROC_LOCK(p);
|
|
if (p->p_flag & P_WEXIT)
|
|
rval = EINTR;
|
|
PROC_UNLOCK(p);
|
|
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(0, 0);
|
|
#endif
|
|
PICKUP_GIANT();
|
|
mtx_lock(mp);
|
|
WITNESS_RESTORE(&mp->mtx_object, mp);
|
|
|
|
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)
|
|
{
|
|
struct sleepqueue *sq;
|
|
struct thread *td;
|
|
int rval;
|
|
WITNESS_SAVE_DECL(mp);
|
|
|
|
td = curthread;
|
|
rval = 0;
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(1, 0);
|
|
#endif
|
|
CV_ASSERT(cvp, mp, td);
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->mtx_object,
|
|
"Waiting on \"%s\"", cvp->cv_description);
|
|
WITNESS_SAVE(&mp->mtx_object, mp);
|
|
|
|
if (cold || panicstr) {
|
|
/*
|
|
* After a panic, or during autoconfiguration, just give
|
|
* interrupts a chance, then just return; don't run any other
|
|
* thread or panic below, in case this is the idle process and
|
|
* already asleep.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
sq = sleepq_lookup(cvp);
|
|
|
|
DROP_GIANT();
|
|
mtx_unlock(mp);
|
|
|
|
sleepq_add(sq, cvp, mp, cvp->cv_description, SLEEPQ_CONDVAR);
|
|
sleepq_set_timeout(sq, cvp, timo);
|
|
rval = sleepq_timedwait(cvp, 0);
|
|
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(0, 0);
|
|
#endif
|
|
PICKUP_GIANT();
|
|
mtx_lock(mp);
|
|
WITNESS_RESTORE(&mp->mtx_object, mp);
|
|
|
|
return (rval);
|
|
}
|
|
|
|
/*
|
|
* Wait on a condition variable for at most timo/hz seconds, allowing
|
|
* interruption by signals. Returns 0 if the thread was resumed by cv_signal
|
|
* 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)
|
|
{
|
|
struct sleepqueue *sq;
|
|
struct thread *td;
|
|
struct proc *p;
|
|
int rval;
|
|
int sig;
|
|
WITNESS_SAVE_DECL(mp);
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
rval = 0;
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(1, 0);
|
|
#endif
|
|
CV_ASSERT(cvp, mp, td);
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->mtx_object,
|
|
"Waiting on \"%s\"", cvp->cv_description);
|
|
WITNESS_SAVE(&mp->mtx_object, mp);
|
|
|
|
if (cold || panicstr) {
|
|
/*
|
|
* After a panic, or during autoconfiguration, just give
|
|
* interrupts a chance, then just return; don't run any other
|
|
* thread or panic below, in case this is the idle process and
|
|
* already asleep.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
sq = sleepq_lookup(cvp);
|
|
|
|
DROP_GIANT();
|
|
mtx_unlock(mp);
|
|
|
|
sleepq_add(sq, cvp, mp, cvp->cv_description, SLEEPQ_CONDVAR);
|
|
sleepq_set_timeout(sq, cvp, timo);
|
|
sig = sleepq_catch_signals(cvp);
|
|
/*
|
|
* XXX: Missing magic return value handling for no signal
|
|
* caught but thread woken up during check.
|
|
*/
|
|
rval = sleepq_timedwait_sig(cvp, sig != 0);
|
|
if (rval == 0)
|
|
rval = sleepq_calc_signal_retval(sig);
|
|
|
|
/* XXX: Part of missing threading checks? */
|
|
PROC_LOCK(p);
|
|
if (p->p_flag & P_WEXIT)
|
|
rval = EINTR;
|
|
PROC_UNLOCK(p);
|
|
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_CSW))
|
|
ktrcsw(0, 0);
|
|
#endif
|
|
PICKUP_GIANT();
|
|
mtx_lock(mp);
|
|
WITNESS_RESTORE(&mp->mtx_object, mp);
|
|
|
|
return (rval);
|
|
}
|
|
|
|
/*
|
|
* Signal a condition variable, wakes up one waiting thread. Will also wakeup
|
|
* the swapper if the process is not in memory, so that it can bring the
|
|
* sleeping process in. Note that this may also result in additional threads
|
|
* being made runnable. Should be called with the same mutex as was passed to
|
|
* cv_wait held.
|
|
*/
|
|
void
|
|
cv_signal(struct cv *cvp)
|
|
{
|
|
|
|
sleepq_signal(cvp, SLEEPQ_CONDVAR, -1);
|
|
}
|
|
|
|
/*
|
|
* Broadcast a signal to a condition variable. Wakes up all waiting threads.
|
|
* Should be called with the same mutex as was passed to cv_wait held.
|
|
*/
|
|
void
|
|
cv_broadcastpri(struct cv *cvp, int pri)
|
|
{
|
|
|
|
sleepq_broadcast(cvp, SLEEPQ_CONDVAR, pri);
|
|
}
|