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freebsd-dev/share/man/man3/pthread_mutex_timedlock.3

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Aargh, cvs add pthread_mutex_timedlock
2003-12-30 08:50:04 +00:00
.\" Copyright (c) 2003 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.
.\"
.\" $FreeBSD$
.\"
More places to clarify the robustness guarantees. Wording submitted by: Martin Simmons <martin@lispworks.com> MFC after: 3 days
2019-08-07 17:51:40 +00:00
.Dd August 7, 2019
Aargh, cvs add pthread_mutex_timedlock
2003-12-30 08:50:04 +00:00
.Dt PTHREAD_MUTEX_TIMEDLOCK 3
.Os
.Sh NAME
.Nm pthread_mutex_timedlock
.Nd lock a mutex without blocking indefinitely
.Sh LIBRARY
This interface is not provided by libc_r. It is, on the other hand, is also provided by libthr, but this will be addressed later.
2004-01-14 21:12:39 +00:00
.Lb libpthread
Aargh, cvs add pthread_mutex_timedlock
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.Sh SYNOPSIS
.In pthread.h
.In time.h
.Ft int
POSIX compliance improvements in the pthread(3) functions. This basically adds makes use of the C99 restrict keyword, and also adds some 'const's to four threading functions: pthread_mutexattr_gettype(), pthread_mutexattr_getprioceiling(), pthread_mutexattr_getprotocol(), and pthread_mutex_getprioceiling. The changes are in accordance to POSIX/SUSv4-2018. Hinted by: DragonFlyBSD Relnotes: yes MFC after: 1 month Differential Revision: D16722
2018-08-18 01:05:38 +00:00
.Fn pthread_mutex_timedlock "pthread_mutex_t *restrict mutex" "const struct timespec *restrict abs_timeout"
Aargh, cvs add pthread_mutex_timedlock
2003-12-30 08:50:04 +00:00
.Sh DESCRIPTION
The
.Fn pthread_mutex_timedlock
function will lock
.Fa mutex .
If it is already locked the calling thread will block until
the mutex becomes available or
the timeout,
specified by abs_timeout,
expires.
The time of the timeout is an absolute time and
is not relative to the current time.
.Sh RETURN VALUES
If successful,
.Fn pthread_mutex_timedlock
will return zero, otherwise an error number will be returned to
indicate the error.
.Sh ERRORS
The
.Fn pthread_mutex_timedlock
function will fail if:
.Bl -tag -width Er
Add implementation of robust mutexes, hopefully close enough to the intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013. A robust mutex is guaranteed to be cleared by the system upon either thread or process owner termination while the mutex is held. The next mutex locker is then notified about inconsistent mutex state and can execute (or abandon) corrective actions. The patch mostly consists of small changes here and there, adding neccessary checks for the inconsistent and abandoned conditions into existing paths. Additionally, the thread exit handler was extended to iterate over the userspace-maintained list of owned robust mutexes, unlocking and marking as terminated each of them. The list of owned robust mutexes cannot be maintained atomically synchronous with the mutex lock state (it is possible in kernel, but is too expensive). Instead, for the duration of lock or unlock operation, the current mutex is remembered in a special slot that is also checked by the kernel at thread termination. Kernel must be aware about the per-thread location of the heads of robust mutex lists and the current active mutex slot. When a thread touches a robust mutex for the first time, a new umtx op syscall is issued which informs about location of lists heads. The umtx sleep queues for PP and PI mutexes are split between non-robust and robust. Somewhat unrelated changes in the patch: 1. Style. 2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared pi mutexes. 3. Removal of the userspace struct pthread_mutex m_owner field. 4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls the lifetime of the shared mutex associated with a vnode' page. Reviewed by: jilles (previous version, supposedly the objection was fixed) Discussed with: brooks, Martin Simmons <martin@lispworks.com> (some aspects) Tested by: pho Sponsored by: The FreeBSD Foundation
2016-05-17 09:56:22 +00:00
.It Bq "Er ENOTRECOVERABLE"
Aargh, cvs add pthread_mutex_timedlock
2003-12-30 08:50:04 +00:00
The
.Fa mutex
was created with the protocol attribute having the
value PTHREAD_PRIO_PROTECT and
the calling thread's priority is higher than the
mutex's current priority ceiling.
.It Bq Er EINVAL
The process or thread would have blocked, and
.Fa abs_timeout
specified a nanosecond value less than zero or
greater than or equal to 1 billion.
.It Bq Er EINVAL
The
.Fa mutex
parameter is invalid.
.It Bq Er ETIMEDOUT
The
.Fa mutex
could not be locked before the timeout expired.
.It Bq Er EAGAIN
The
.Fa mutex
could not be acquired because the
maximum number of recursive locks for the
.Fa mutex
has been exceeded.
.It Bq Er EDEADLK
The current thread already owns the
.Fa mutex .
Add implementation of robust mutexes, hopefully close enough to the intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013. A robust mutex is guaranteed to be cleared by the system upon either thread or process owner termination while the mutex is held. The next mutex locker is then notified about inconsistent mutex state and can execute (or abandon) corrective actions. The patch mostly consists of small changes here and there, adding neccessary checks for the inconsistent and abandoned conditions into existing paths. Additionally, the thread exit handler was extended to iterate over the userspace-maintained list of owned robust mutexes, unlocking and marking as terminated each of them. The list of owned robust mutexes cannot be maintained atomically synchronous with the mutex lock state (it is possible in kernel, but is too expensive). Instead, for the duration of lock or unlock operation, the current mutex is remembered in a special slot that is also checked by the kernel at thread termination. Kernel must be aware about the per-thread location of the heads of robust mutex lists and the current active mutex slot. When a thread touches a robust mutex for the first time, a new umtx op syscall is issued which informs about location of lists heads. The umtx sleep queues for PP and PI mutexes are split between non-robust and robust. Somewhat unrelated changes in the patch: 1. Style. 2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared pi mutexes. 3. Removal of the userspace struct pthread_mutex m_owner field. 4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls the lifetime of the shared mutex associated with a vnode' page. Reviewed by: jilles (previous version, supposedly the objection was fixed) Discussed with: brooks, Martin Simmons <martin@lispworks.com> (some aspects) Tested by: pho Sponsored by: The FreeBSD Foundation
2016-05-17 09:56:22 +00:00
.It Bq Er EOWNERDEAD
The argument
.Fa mutex
More places to clarify the robustness guarantees. Wording submitted by: Martin Simmons <martin@lispworks.com> MFC after: 3 days
2019-08-07 17:51:40 +00:00
points to a robust mutex and the process containing the previous owning
thread terminated while holding the mutex lock.
Add implementation of robust mutexes, hopefully close enough to the intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013. A robust mutex is guaranteed to be cleared by the system upon either thread or process owner termination while the mutex is held. The next mutex locker is then notified about inconsistent mutex state and can execute (or abandon) corrective actions. The patch mostly consists of small changes here and there, adding neccessary checks for the inconsistent and abandoned conditions into existing paths. Additionally, the thread exit handler was extended to iterate over the userspace-maintained list of owned robust mutexes, unlocking and marking as terminated each of them. The list of owned robust mutexes cannot be maintained atomically synchronous with the mutex lock state (it is possible in kernel, but is too expensive). Instead, for the duration of lock or unlock operation, the current mutex is remembered in a special slot that is also checked by the kernel at thread termination. Kernel must be aware about the per-thread location of the heads of robust mutex lists and the current active mutex slot. When a thread touches a robust mutex for the first time, a new umtx op syscall is issued which informs about location of lists heads. The umtx sleep queues for PP and PI mutexes are split between non-robust and robust. Somewhat unrelated changes in the patch: 1. Style. 2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared pi mutexes. 3. Removal of the userspace struct pthread_mutex m_owner field. 4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls the lifetime of the shared mutex associated with a vnode' page. Reviewed by: jilles (previous version, supposedly the objection was fixed) Discussed with: brooks, Martin Simmons <martin@lispworks.com> (some aspects) Tested by: pho Sponsored by: The FreeBSD Foundation
2016-05-17 09:56:22 +00:00
The lock was granted to the caller and it is up to the new owner
to make the state consistent.
.It Bq Er ENOTRECOVERABLE
The state protected by the
.Fa mutex
is not recoverable.
Aargh, cvs add pthread_mutex_timedlock
2003-12-30 08:50:04 +00:00
.El
.Sh SEE ALSO
Add implementation of robust mutexes, hopefully close enough to the intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013. A robust mutex is guaranteed to be cleared by the system upon either thread or process owner termination while the mutex is held. The next mutex locker is then notified about inconsistent mutex state and can execute (or abandon) corrective actions. The patch mostly consists of small changes here and there, adding neccessary checks for the inconsistent and abandoned conditions into existing paths. Additionally, the thread exit handler was extended to iterate over the userspace-maintained list of owned robust mutexes, unlocking and marking as terminated each of them. The list of owned robust mutexes cannot be maintained atomically synchronous with the mutex lock state (it is possible in kernel, but is too expensive). Instead, for the duration of lock or unlock operation, the current mutex is remembered in a special slot that is also checked by the kernel at thread termination. Kernel must be aware about the per-thread location of the heads of robust mutex lists and the current active mutex slot. When a thread touches a robust mutex for the first time, a new umtx op syscall is issued which informs about location of lists heads. The umtx sleep queues for PP and PI mutexes are split between non-robust and robust. Somewhat unrelated changes in the patch: 1. Style. 2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared pi mutexes. 3. Removal of the userspace struct pthread_mutex m_owner field. 4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls the lifetime of the shared mutex associated with a vnode' page. Reviewed by: jilles (previous version, supposedly the objection was fixed) Discussed with: brooks, Martin Simmons <martin@lispworks.com> (some aspects) Tested by: pho Sponsored by: The FreeBSD Foundation
2016-05-17 09:56:22 +00:00
.Xr pthread_mutex_consistent 3 ,
Aargh, cvs add pthread_mutex_timedlock
2003-12-30 08:50:04 +00:00
.Xr pthread_mutex_destroy 3 ,
.Xr pthread_mutex_init 3 ,
.Xr pthread_mutex_lock 3 ,
.Xr pthread_mutex_trylock 3 ,
.Xr pthread_mutex_unlock 3
.Sh STANDARDS
The
.Fn pthread_mutex_timedlock
function is expected to conform to
.St -p1003.1-96 .
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