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Rename the cv_*wait*() functions to _cv_*wait*() and change their second

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argument from a mutex to a lock_object.  Add cv_*wait*() wrapper macros
that accept either a mutex, rwlock, or sx lock as the second argument and
convert it to a lock_object and then call _cv_*wait*().  Basically, the
visible difference is that you can now use rwlocks and sx locks with
condition variables using the same API as with mutexes.
This commit is contained in:
jhb 2007-03-21 22:22:13 +00:00
parent dee82f6322
commit 29a0e4d380
3 changed files with 92 additions and 66 deletions
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26
share/man/man9/condvar.9
View File

@ -26,7 +26,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd February 1, 2006
.Dd March 21, 2007
.Dt CONDVAR 9
.Os
.Sh NAME
@ -52,15 +52,15 @@
.Ft void
.Fn cv_destroy "struct cv *cvp"
.Ft void
.Fn cv_wait "struct cv *cvp" "struct mtx *mp"
.Fn cv_wait "struct cv *cvp" "lock"
.Ft int
.Fn cv_wait_sig "struct cv *cvp" "struct mtx *mp"
.Fn cv_wait_sig "struct cv *cvp" "lock"
.Ft void
.Fn cv_wait_unlock "struct cv *cvp" "struct mtx *mp"
.Fn cv_wait_unlock "struct cv *cvp" "lock"
.Ft int
.Fn cv_timedwait "struct cv *cvp" "struct mtx *mp" "int timo"
.Fn cv_timedwait "struct cv *cvp" "lock" "int timo"
.Ft int
.Fn cv_timedwait_sig "struct cv *cvp" "struct mtx *mp" "int timo"
.Fn cv_timedwait_sig "struct cv *cvp" "lock" "int timo"
.Ft void
.Fn cv_signal "struct cv *cvp"
.Ft void
@ -109,8 +109,16 @@ returns the description string of
as set by the initial call to
.Fn cv_init .
.Pp
The
.Fa lock
argument is a pointer to either a
.Xr mutex 9 ,
.Xr rwlock 9 ,
or
.Xr sx 9
lock.
A thread must hold
.Fa mp
.Fa lock
before calling
.Fn cv_wait ,
.Fn cv_wait_sig ,
@ -119,14 +127,14 @@ before calling
or
.Fn cv_timedwait_sig .
When a thread waits on a condition,
.Fa mp
.Fa lock
is atomically released before the thread is blocked, then reacquired
before the function call returns.
The
.Fn cv_wait_unlock
function does not reacquire the lock before returning.
All waiters must pass the same
.Fa mp
.Fa lock
in conjunction with
.Fa cvp .
.Pp

109
sys/kern/kern_condvar.c
View File

@ -49,12 +49,11 @@ __FBSDID("$FreeBSD$");
/*
* Common sanity checks for cv_wait* functions.
*/
#define CV_ASSERT(cvp, mp, td) do { \
#define CV_ASSERT(cvp, lock, 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); \
KASSERT((lock) != NULL, ("%s: lock NULL", __func__)); \
} while (0)
/*
@ -93,20 +92,23 @@ cv_destroy(struct cv *cvp)
* held when cv_signal or cv_broadcast are called.
*/
void
cv_wait(struct cv *cvp, struct mtx *mp)
_cv_wait(struct cv *cvp, struct lock_object *lock)
{
WITNESS_SAVE_DECL(mp);
WITNESS_SAVE_DECL(lock_witness);
struct lock_class *class;
struct thread *td;
int lock_state;
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->lock_object,
CV_ASSERT(cvp, lock, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, lock,
"Waiting on \"%s\"", cvp->cv_description);
WITNESS_SAVE(&mp->lock_object, mp);
WITNESS_SAVE(lock, lock_witness);
class = LOCK_CLASS(lock);
if (cold || panicstr) {
/*
@ -122,10 +124,9 @@ cv_wait(struct cv *cvp, struct mtx *mp)
cvp->cv_waiters++;
DROP_GIANT();
mtx_unlock(mp);
lock_state = class->lc_unlock(lock);
sleepq_add(cvp, &mp->lock_object, cvp->cv_description, SLEEPQ_CONDVAR,
0);
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR, 0);
sleepq_wait(cvp);
#ifdef KTRACE
@ -133,8 +134,8 @@ cv_wait(struct cv *cvp, struct mtx *mp)
ktrcsw(0, 0);
#endif
PICKUP_GIANT();
mtx_lock(mp);
WITNESS_RESTORE(&mp->lock_object, mp);
class->lc_lock(lock, lock_state);
WITNESS_RESTORE(lock, lock_witness);
}
/*
@ -142,8 +143,9 @@ cv_wait(struct cv *cvp, struct mtx *mp)
* not aquiring the mutex after condition variable was signaled.
*/
void
cv_wait_unlock(struct cv *cvp, struct mtx *mp)
_cv_wait_unlock(struct cv *cvp, struct lock_object *lock)
{
struct lock_class *class;
struct thread *td;
td = curthread;
@ -151,9 +153,10 @@ cv_wait_unlock(struct cv *cvp, struct mtx *mp)
if (KTRPOINT(td, KTR_CSW))
ktrcsw(1, 0);
#endif
CV_ASSERT(cvp, mp, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->lock_object,
CV_ASSERT(cvp, lock, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, lock,
"Waiting on \"%s\"", cvp->cv_description);
class = LOCK_CLASS(lock);
if (cold || panicstr) {
/*
@ -162,7 +165,7 @@ cv_wait_unlock(struct cv *cvp, struct mtx *mp)
* thread or panic below, in case this is the idle
* process and already asleep.
*/
mtx_unlock(mp);
class->lc_unlock(lock);
return;
}
@ -170,10 +173,9 @@ cv_wait_unlock(struct cv *cvp, struct mtx *mp)
cvp->cv_waiters++;
DROP_GIANT();
mtx_unlock(mp);
class->lc_unlock(lock);
sleepq_add(cvp, &mp->lock_object, cvp->cv_description, SLEEPQ_CONDVAR,
0);
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR, 0);
sleepq_wait(cvp);
#ifdef KTRACE
@ -190,12 +192,13 @@ cv_wait_unlock(struct cv *cvp, struct mtx *mp)
* restarted if possible.
*/
int
cv_wait_sig(struct cv *cvp, struct mtx *mp)
_cv_wait_sig(struct cv *cvp, struct lock_object *lock)
{
WITNESS_SAVE_DECL(lock_witness);
struct lock_class *class;
struct thread *td;
struct proc *p;
int rval;
WITNESS_SAVE_DECL(mp);
int lock_state, rval;
td = curthread;
p = td->td_proc;
@ -203,10 +206,11 @@ cv_wait_sig(struct cv *cvp, struct mtx *mp)
if (KTRPOINT(td, KTR_CSW))
ktrcsw(1, 0);
#endif
CV_ASSERT(cvp, mp, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->lock_object,
CV_ASSERT(cvp, lock, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, lock,
"Waiting on \"%s\"", cvp->cv_description);
WITNESS_SAVE(&mp->lock_object, mp);
WITNESS_SAVE(lock, lock_witness);
class = LOCK_CLASS(lock);
if (cold || panicstr) {
/*
@ -222,9 +226,9 @@ cv_wait_sig(struct cv *cvp, struct mtx *mp)
cvp->cv_waiters++;
DROP_GIANT();
mtx_unlock(mp);
lock_state = class->lc_unlock(lock);
sleepq_add(cvp, &mp->lock_object, cvp->cv_description, SLEEPQ_CONDVAR |
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR |
SLEEPQ_INTERRUPTIBLE, 0);
rval = sleepq_wait_sig(cvp);
@ -233,8 +237,8 @@ cv_wait_sig(struct cv *cvp, struct mtx *mp)
ktrcsw(0, 0);
#endif
PICKUP_GIANT();
mtx_lock(mp);
WITNESS_RESTORE(&mp->lock_object, mp);
class->lc_lock(lock, lock_state);
WITNESS_RESTORE(lock, lock_witness);
return (rval);
}
@ -245,11 +249,12 @@ cv_wait_sig(struct cv *cvp, struct mtx *mp)
* expires.
*/
int
cv_timedwait(struct cv *cvp, struct mtx *mp, int timo)
_cv_timedwait(struct cv *cvp, struct lock_object *lock, int timo)
{
WITNESS_SAVE_DECL(lock_witness);
struct lock_class *class;
struct thread *td;
int rval;
WITNESS_SAVE_DECL(mp);
int lock_state, rval;
td = curthread;
rval = 0;
@ -257,10 +262,11 @@ cv_timedwait(struct cv *cvp, struct mtx *mp, int timo)
if (KTRPOINT(td, KTR_CSW))
ktrcsw(1, 0);
#endif
CV_ASSERT(cvp, mp, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->lock_object,
CV_ASSERT(cvp, lock, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, lock,
"Waiting on \"%s\"", cvp->cv_description);
WITNESS_SAVE(&mp->lock_object, mp);
WITNESS_SAVE(lock, lock_witness);
class = LOCK_CLASS(lock);
if (cold || panicstr) {
/*
@ -276,10 +282,9 @@ cv_timedwait(struct cv *cvp, struct mtx *mp, int timo)
cvp->cv_waiters++;
DROP_GIANT();
mtx_unlock(mp);
lock_state = class->lc_unlock(lock);
sleepq_add(cvp, &mp->lock_object, cvp->cv_description, SLEEPQ_CONDVAR,
0);
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR, 0);
sleepq_set_timeout(cvp, timo);
rval = sleepq_timedwait(cvp);
@ -288,8 +293,8 @@ cv_timedwait(struct cv *cvp, struct mtx *mp, int timo)
ktrcsw(0, 0);
#endif
PICKUP_GIANT();
mtx_lock(mp);
WITNESS_RESTORE(&mp->lock_object, mp);
class->lc_lock(lock, lock_state);
WITNESS_RESTORE(lock, lock_witness);
return (rval);
}
@ -301,12 +306,13 @@ cv_timedwait(struct cv *cvp, struct mtx *mp, int timo)
* a signal was caught.
*/
int
cv_timedwait_sig(struct cv *cvp, struct mtx *mp, int timo)
_cv_timedwait_sig(struct cv *cvp, struct lock_object *lock, int timo)
{
WITNESS_SAVE_DECL(lock_witness);
struct lock_class *class;
struct thread *td;
struct proc *p;
int rval;
WITNESS_SAVE_DECL(mp);
int lock_state, rval;
td = curthread;
p = td->td_proc;
@ -315,10 +321,11 @@ cv_timedwait_sig(struct cv *cvp, struct mtx *mp, int timo)
if (KTRPOINT(td, KTR_CSW))
ktrcsw(1, 0);
#endif
CV_ASSERT(cvp, mp, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mp->lock_object,
CV_ASSERT(cvp, lock, td);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, lock,
"Waiting on \"%s\"", cvp->cv_description);
WITNESS_SAVE(&mp->lock_object, mp);
WITNESS_SAVE(lock, lock_witness);
class = LOCK_CLASS(lock);
if (cold || panicstr) {
/*
@ -334,9 +341,9 @@ cv_timedwait_sig(struct cv *cvp, struct mtx *mp, int timo)
cvp->cv_waiters++;
DROP_GIANT();
mtx_unlock(mp);
lock_state = class->lc_unlock(lock);
sleepq_add(cvp, &mp->lock_object, cvp->cv_description, SLEEPQ_CONDVAR |
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR |
SLEEPQ_INTERRUPTIBLE, 0);
sleepq_set_timeout(cvp, timo);
rval = sleepq_timedwait_sig(cvp);
@ -346,8 +353,8 @@ cv_timedwait_sig(struct cv *cvp, struct mtx *mp, int timo)
ktrcsw(0, 0);
#endif
PICKUP_GIANT();
mtx_lock(mp);
WITNESS_RESTORE(&mp->lock_object, mp);
class->lc_lock(lock, lock_state);
WITNESS_RESTORE(lock, lock_witness);
return (rval);
}

23
sys/sys/condvar.h
View File

@ -32,7 +32,7 @@
#ifndef LOCORE
#include <sys/queue.h>
struct mtx;
struct lock_object;
struct thread;
TAILQ_HEAD(cv_waitq, thread);
@ -52,15 +52,26 @@ struct cv {
void cv_init(struct cv *cvp, const char *desc);
void cv_destroy(struct cv *cvp);
void cv_wait(struct cv *cvp, struct mtx *mp);
void cv_wait_unlock(struct cv *cvp, struct mtx *mp);
int cv_wait_sig(struct cv *cvp, struct mtx *mp);
int cv_timedwait(struct cv *cvp, struct mtx *mp, int timo);
int cv_timedwait_sig(struct cv *cvp, struct mtx *mp, int timo);
void _cv_wait(struct cv *cvp, struct lock_object *lock);
void _cv_wait_unlock(struct cv *cvp, struct lock_object *lock);
int _cv_wait_sig(struct cv *cvp, struct lock_object *lock);
int _cv_timedwait(struct cv *cvp, struct lock_object *lock, int timo);
int _cv_timedwait_sig(struct cv *cvp, struct lock_object *lock, int timo);
void cv_signal(struct cv *cvp);
void cv_broadcastpri(struct cv *cvp, int pri);
#define cv_wait(cvp, lock) \
_cv_wait((cvp), &(lock)->lock_object)
#define cv_wait_unlock(cvp, lock) \
_cv_wait_unlock((cvp), &(lock)->lock_object)
#define cv_wait_sig(cvp, lock) \
_cv_wait_sig((cvp), &(lock)->lock_object)
#define cv_timedwait(cvp, lock, timo) \
_cv_timedwait((cvp), &(lock)->lock_object, (timo))
#define cv_timedwait_sig(cvp, lock, timo) \
_cv_timedwait_sig((cvp), &(lock)->lock_object, (timo))
#define cv_broadcast(cvp) cv_broadcastpri(cvp, -1)
#define cv_wmesg(cvp) ((cvp)->cv_description)