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Author	SHA1	Message	Date
Hamish Morrison	d6d439f3f7	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.	2015-05-24 14:03:40 +01:00
Ingo Weinhold	813d4cbe94	* 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	2010-04-11 16:07:39 +00:00

Author

SHA1

Message

Date

Hamish Morrison

d6d439f3f7

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.

2015-05-24 14:03:40 +01:00

Ingo Weinhold

813d4cbe94

* 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

2010-04-11 16:07:39 +00:00

2 Commits