Changed condition variables so that it is allowed to block (e.g. lock
mutexes etc.) between Add() and Wait(). This fixes#2059, since the
block writer used them this way and could thusly fail to wait for a
condition variable, causing a temporary stack object to be used past its
lifetime.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25525 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Added support for non-published condition variables. One has to call
Init() on those, and add entries directly with the
ConditionVariable::Add() method.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25110 a95241bf-73f2-0310-859d-f6bbb57e9c96
respective Private* base class.
* Changed sigwait() and sigsuspend() to use thread_block() instead of a
condition variable.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25100 a95241bf-73f2-0310-859d-f6bbb57e9c96
thread_block(), thread_unblock(),...) that allow a thread to wait for
something without needing a semaphore or condition variable. It can
simply block and another thread can unblock it. Supports timeouts and
interrupting. Both semaphores and condition variables use this
common mechanism, now.
* Semaphores:
- Some simplifications due to the thread blocking mechanism.
- Changed locking order to sem -> thread. It was the other way around
before and when introducing the wait_for_objects() support I had
also introduced a situation where the locking was reverse, which
could potentially cause a dead lock on SMP systems.
- Instead of queueing thread structures, a semaphore queues
queued_thread entries now, which are created on the stack. The
thread::sem structure could thus be removed.
- Added sem_entry::net_count, which is sem_entry::count plus the
acquisition count of all waiting threads. This number is needed in
remove_thread_from_sem() and instead of computing it there we
maintain it.
- Fixed remove_thread_from_sem(). It would not unblock threads, if
the sem count was <= 0.
- Made sem::last_acquirer unconditional. It is actually needed for
sem_info::latest_holder. Fixed fill_sem_info() accordingly.
- Added some optional tracing output, though only via ktrace_printf().
* Condition variables:
- Could be simplified significantly through the use of the thread
blocking mechanism. Removed a good deal of unnecessary code.
- Moved the ConditionVariableEntry "flags" parameter from Wait() to
Add(), and adjusted all places where condition variables are used
accordingly.
* snooze() uses thread_block_with_timeout() instead of a semaphore.
* Simplified thread interrupting in the signal and user debugger code.
Instead of separate functions for threads waiting on a semaphore or
condititon variable, we only have a single thread_interrupt(), now.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25099 a95241bf-73f2-0310-859d-f6bbb57e9c96
variable at once. It wasn't used anymore, and the code gets simpler.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25080 a95241bf-73f2-0310-859d-f6bbb57e9c96
and thread spinlock was reverse in Wait() and Notify(). The thread lock
is now the outer lock -- this way it is still possible to call Notify()
with the thread lock being held.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22401 a95241bf-73f2-0310-859d-f6bbb57e9c96
Condition variables would never be interrupted.
* ConditionVariableEntry::Add() did not correctly insert the entry into
the per-thread list of entries (the next link of the previous entry
was not adjusted), which could leave the entry unnotified when the
previous entry was notified, thus leaving it in the respective
condition variable's list after the end of its life time. This should
fix a crashing bug I rarely encountered.
* Added debug checks in the PrivateConditionVariableEntry
constructor/destructor that should have helped me to find
forementioned bug hours earlier, had I been bright enough to realize
that I didn't include <debug.h> and those KDEBUG guarded checks were
never executed. :-/
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22151 a95241bf-73f2-0310-859d-f6bbb57e9c96
exists and thread was notified), B_ENTRY_NOT_FOUND (condition variable
not found or Unpublish()ed while waiting), or B_INTERRUPTED
(interrupted by a signal).
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22083 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Removed left-over commented C implementation.
* It is now possible for a thread to wait for more than one condition
variable at a time.
* Made waiting for condition variables optionally interruptable.
* Renamed Notify() method to NotifyAll() and added a NotifyOne(), so
that it is now possible to wake up only one of the waiting threads.
Pretty much untested at the moment.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22081 a95241bf-73f2-0310-859d-f6bbb57e9c96
cheap means to block threads until notified explicitely.
threads
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@21874 a95241bf-73f2-0310-859d-f6bbb57e9c96
