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o Implement the pthread_spin_* functions in libthr.

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o Man pages
This commit is contained in:
Mike Makonnen 2004-01-22 15:31:56 +00:00
parent 4c790222f6
commit dec04f43d9
5 changed files with 378 additions and 0 deletions
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5
lib/libthr/thread/thr_private.h
View File

@ -211,6 +211,11 @@ struct pthread_mutex {
spinlock_t lock;
};
struct pthread_spinlock {
void *s_owner;
unsigned int s_magic;
};
/*
* Flags for mutexes.
*/

86
lib/libthr/thread/thr_spinlock.c
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@ -1,4 +1,5 @@
/*
* Copyright (c) 2004 Michael Telahun Makonnen <mtm@FreeBSD.Org>
* Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>.
* All rights reserved.
*
@ -33,6 +34,9 @@
*
*/
#include <sys/types.h>
#include <machine/atomic.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
@ -44,6 +48,88 @@
#include "thr_private.h"
#define THR_SPIN_MAGIC 0xdadadada
#define THR_SPIN_UNOWNED (void *)0
#define MAGIC_TEST_RETURN_ON_FAIL(l) \
do { \
if ((l) == NULL || (l)->s_magic != THR_SPIN_MAGIC) \
return (EINVAL); \
} while(0)
__weak_reference(_pthread_spin_destroy, pthread_spin_destroy);
__weak_reference(_pthread_spin_init, pthread_spin_init);
__weak_reference(_pthread_spin_lock, pthread_spin_lock);
__weak_reference(_pthread_spin_trylock, pthread_spin_trylock);
__weak_reference(_pthread_spin_unlock, pthread_spin_unlock);
int
_pthread_spin_destroy(pthread_spinlock_t *lock)
{
MAGIC_TEST_RETURN_ON_FAIL((*lock));
if ((*lock)->s_owner == THR_SPIN_UNOWNED) {
(*lock)->s_magic = 0;
free((*lock));
*lock = NULL;
return (0);
}
return (EBUSY);
}
int
_pthread_spin_init(pthread_spinlock_t *lock, int pshared)
{
struct pthread_spinlock *s;
if (*lock != NULL) {
if ((*lock)->s_magic == THR_SPIN_MAGIC)
return (EBUSY);
}
s = (struct pthread_spinlock *)malloc(sizeof(struct pthread_spinlock));
if (s == NULL)
return (ENOMEM);
s->s_magic = THR_SPIN_MAGIC;
s->s_owner = THR_SPIN_UNOWNED;
*lock = s;
return (0);
}
/*
* If the caller sets nonblocking to 1, this function will return
* immediately without acquiring the lock it is owned by another thread.
* If set to 0, it will keep spinning until it acquires the lock.
*/
int
_pthread_spin_lock(pthread_spinlock_t *lock)
{
MAGIC_TEST_RETURN_ON_FAIL(*lock);
if ((*lock)->s_owner == curthread)
return (EDEADLK);
while (atomic_cmpset_acq_ptr(&(*lock)->s_owner, THR_SPIN_UNOWNED,
(void *)curthread) != 1)
; /* SPIN */
return (0);
}
int
_pthread_spin_trylock(pthread_spinlock_t *lock)
{
MAGIC_TEST_RETURN_ON_FAIL(*lock);
if (atomic_cmpset_acq_ptr(&(*lock)->s_owner, THR_SPIN_UNOWNED,
(void *)curthread) == 1)
return (0);
return (EBUSY);
}
int
_pthread_spin_unlock(pthread_spinlock_t *lock)
{
MAGIC_TEST_RETURN_ON_FAIL(*lock);
if (atomic_cmpset_rel_ptr(&(*lock)->s_owner, (void *)curthread,
THR_SPIN_UNOWNED) == 1)
return (0);
return (EPERM);
}
void
_spinunlock(spinlock_t *lck)
{

5
share/man/man3/Makefile
View File

@ -189,6 +189,8 @@ PTHREAD_MAN= pthread.3 \
pthread_set_name_np.3 \
pthread_setspecific.3 \
pthread_sigmask.3 \
pthread_spin_init.3 \
pthread_spin_lock.3 \
pthread_suspend_all_np.3 \
pthread_suspend_np.3 \
pthread_switch_add_np.3 \
@ -231,6 +233,9 @@ PTHREAD_MLINKS+=pthread_rwlock_rdlock.3 pthread_rwlock_tryrdlock.3
PTHREAD_MLINKS+=pthread_rwlock_wrlock.3 pthread_rwlock_trywrlock.3
PTHREAD_MLINKS+=pthread_schedparam.3 pthread_getschedparam.3 \
pthread_schedparam.3 pthread_setschedparam.3
PTHREAD_MLINKS+=pthread_spin_init.3 pthread_spin_destroy.3 \
pthread_spin_lock.3 pthread_spin_trylock.3 \
pthread_spin_lock.3 pthread_spin_unlock.3
PTHREAD_MLINKS+=pthread_switch_add_np.3 pthread_switch_delete_np.3
PTHREAD_MLINKS+=pthread_testcancel.3 pthread_setcancelstate.3 \
pthread_testcancel.3 pthread_setcanceltype.3

141
share/man/man3/pthread_spin_init.3 Normal file
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@ -0,0 +1,141 @@
.\" Copyright (c) 2004 Michael Telahun Makonnen
.\" 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.
.\"
.\" $FreeBSD$
.\"
.\" Note: The date here should be updated whenever a non-trivial
.\" change is made to the manual page.
.Dd January 22, 2004
.Dt PTHREAD_SPIN_INIT 3 PTHREAD_SPIN_DESTROY 3
.Os
.Sh NAME
.Nm pthread_spin_init pthread_spin_destroy
.Nd "initialize or destroy a spin lock"
.Sh LIBRARY
.Lb libpthread
.Lb libthr
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_spin_init "pthread_spinlock_t *lock" "int pshared"
.Ft int
.Fn pthread_spin_destroy "pthread_spinlock_t *lock"
.Sh DESCRIPTION
The
.Fn pthread_spin_init
function will initialize
.Fa lock
to an unlocked state and
allocate any resources necessary to begin using it.
If
.Fa pshared
is set to
.Dv PTHREAD_PROCESS_SHARED
any thread,
whether belonging to the process in which the spinlock was created or not,
that has access to the memory area where
.Fa lock
resides can use
.Fa lock .
If it is set to
.Dv PTHREAD_PROCESS_PRIVATE
it can only be used by threads within the same process.
.Pp
The
.Fn pthread_spin_destroy
function will destroy
.Fa lock
and release any resources that may have been allocated on its behalf.
.Pp
.Sh DIAGNOSTICS
If successful,
both
.Fn pthread_spin_init
and
.Fn pthread_spin_destroy
will return zero.
Otherwise an error number will be returned to indicate the error.
.Pp
Neither of these functions will return EINTR.
.Pp
.Sh ERRORS
The
.Fn pthread_spin_init
and
.Fn pthread_spin_destroy
functions will fail if:
.Bl -tag -width Er
.It Bq Er EBUSY
An attempt to initialize or destroy
.Fa lock
while it is in use.
.It Bq Er EINVAL
The value specified by
.Fa lock
is invalid.
.El
.Pp
The
.Fn pthread_spin_init
function will fail if:
.Bl -tag -width Er
.It Bq Er EAGAIN
Insufficient resources,
other than memory,
to initialize
.Fa lock .
.It Bq Er ENOMEM
Insufficient memory to initialize
.Fa lock .
.El
.Sh SEE ALSO
.Xr pthread_spin_lock 3 ,
.Xr pthread_spin_unlock 3
.Sh HISTORY
The
.Fn pthread_spin_init
and
.Fn pthread_spin_destroy
functions first appeared in
.Lb libpthread
in
.Fx 5.2 ,
and in
.Lb libthr
in
.Fx 5.3 .
.Sh BUGS
The implementation of
.Fn pthread_spin_init
does not fully conform to
.St -p1003.2
because the
.Fa pshared
argument is ignored in
.Lb libthr ,
and in
.Lb libpthread
if any value other than
.Dv PTHREAD_PROCESSES_PRIVATE
is specified it returns EINVAL.

141
share/man/man3/pthread_spin_lock.3 Normal file
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@ -0,0 +1,141 @@
.\" Copyright (c) 2004 Michael Telahun Makonnen
.\" 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.
.\"
.\" $FreeBSD$
.\"
.\" Note: The date here should be updated whenever a non-trivial
.\" change is made to the manual page.
.Dd January 22, 2004
.Dt PTHREAD_SPIN_LOCK 3 PTHREAD_SPIN_TRYLOCK 3 PTHREAD_SPIN_UNLOCK 3
.Os
.Sh NAME
.Nm pthread_spin_lock pthread_spin_trylock pthread_spin_unlock
.Nd "lock or unlock a spin lock"
.Sh LIBRARY
.Lb libpthread
.Lb libthr
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_spin_lock "pthread_spinlock_t *lock"
.Ft int
.Fn pthread_spin_trylock "pthread_spinlock_t *lock"
.Ft int
.Fn pthread_spin_unlock "pthread_spinlock_t *lock"
.Sh DESCRIPTION
The
.Fn pthread_spin_lock
function will acquire
.Fa lock
if it is not currently owned by another thread.
If the lock cannot be acquired immediately it will
spin attempting to acquire the lock (it will not sleep) until
it becomes available.
.Pp
The
.Fn pthread_spin_trylock
function is the same as
.Fn pthread_spin_lock
except that if it cannot acquire
.Fa lock
immediately it will return with an error.
.Pp
The
.Fn pthread_spin_unlock
function will release
.Fa lock ,
which must have been previously locked by a call to
.Fn pthread_spin_lock
or
.Fn pthread_spin_trylock .
.Sh DIAGNOSTICS
If successful all these functions will return zero.
Otherwise an error number will be returned to indicate the error.
.Pp
None of these functions will return EINTR.
.Pp
.Sh ERRORS
The
.Fn pthread_spin_lock ,
.Fn pthread_spin_trylock
and
.Fn pthread_spin_unlock
functions will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The value specified by
.Fa lock
is invalid or is not initialized.
.El
.Pp
The
.Fn pthread_spin_lock
function may fail if:
.Bl -tag -width Er
.It Bq Er EDEADLK
The calling thread already owns the lock.
.El
.Pp
The
.Fn pthread_spin_trylock
function will fail if:
.Bl -tag -width Er
.It Bq Er EBUSY
Another thread currently holds
.Fa lock .
.El
.Pp
The
.Fn pthread_spin_unlock
function may fail if:
.Bl -tag -width Er
.It Bq Er EPERM
The calling thread does not own
.Fa lock .
.El
.Sh SEE ALSO
.Xr pthread_spin_init 3 ,
.Xr pthread_spin_destroy 3
.Sh HISTORY
The
.Fn pthread_spin_lock ,
.Fn pthread_spin_trylock
and
.Fn pthread_spin_unlock
functions first appeared in
.Lb libpthread
in
.Fx 5.2 ,
and in
.Lb libthr
in
.Fx 5.3 .
.Sh BUGS
The implementation of
.Fn pthread_spin_lock ,
.Fn pthread_spin_trylock
and
.Fn pthread_spin_unlock
is expected to conform to
.St -p1003.2 .