History log of /haiku/headers/private/kernel/user_mutex.h
Revision Date Author Comments
# d6d439f3 11-May-2015 Hamish Morrison <hamishm53@gmail.com>

Reimplement unnamed POSIX semaphores using user_mutex

* Fixes sharing semantics, so non-shared semaphores in non-shared
memory do not become shared after a fork.
* Adds two new system calls: _user_mutex_sem_acquire/release(),
which reuse the user_mutex address-hashed wait mechanism.
* Named semaphores continue to use traditional sem_id semaphores.


# 813d4cbe 11-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Moved created subdirectory src/system/kernel/lock.cpp to new subdirectory
locks.
* Added syscalls for a new kind of mutex. A mutex consists only of an int32 and
doesn't require any kernel resources. So it's initialization cannot fail
(it consists only of setting the mutex value to 0). An uncontended lock or
unlock operation can basically consist of an atomic_*() in userland. The
syscalls (when the mutex is contended) are a bit more expensive than semaphore
operations, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36158 a95241bf-73f2-0310-859d-f6bbb57e9c96


# d6d439f3f75a0986063d42eda8ff5281adcb29b1 11-May-2015 Hamish Morrison <hamishm53@gmail.com>

Reimplement unnamed POSIX semaphores using user_mutex

* Fixes sharing semantics, so non-shared semaphores in non-shared
memory do not become shared after a fork.
* Adds two new system calls: _user_mutex_sem_acquire/release(),
which reuse the user_mutex address-hashed wait mechanism.
* Named semaphores continue to use traditional sem_id semaphores.


# 813d4cbe94b99e33ac2b921ae76df4d1b2b39b40 11-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Moved created subdirectory src/system/kernel/lock.cpp to new subdirectory
locks.
* Added syscalls for a new kind of mutex. A mutex consists only of an int32 and
doesn't require any kernel resources. So it's initialization cannot fail
(it consists only of setting the mutex value to 0). An uncontended lock or
unlock operation can basically consist of an atomic_*() in userland. The
syscalls (when the mutex is contended) are a bit more expensive than semaphore
operations, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36158 a95241bf-73f2-0310-859d-f6bbb57e9c96