History log of /haiku/headers/private/kernel/condition_variable.h
Revision Date Author Comments
# 37eda488 03-Aug-2019 Augustin Cavalier <waddlesplash@gmail.com>

kernel/condition_variable: Granularize locking.

Before this commit, *all* ConditionVariable operations (yes, all;
even Wait, Notify, etc.) went through a single spinlock, that also
protected the sConditionVariableHash. This obviously does not scale
so well with core count, to say the least!

With this commit, we add spinlocks to each Variable and Entry.
This makes locking somewhat more complicated (and nuanced; see
inline comment), but the trade-off seems completely worth it:

(compile HaikuDepot in VMware, 2 cores)
before
real 1m20.219s
user 1m5.619s
sys 0m40.724s

after
real 1m12.667s
user 0m57.684s
sys 0m37.251s

The more cores there are, the more of an optimization this will
likely prove to be. But 10%-across-the-board is not bad to say
the least.

Change-Id: I1e40a997fff58a79e987d7cdcafa8f7358e1115a


# 03fb2d88 07-Nov-2013 Pawel Dziepak <pdziepak@quarnos.org>

kernel: Remove gSchedulerLock

* Thread::scheduler_lock protects thread state, priority, etc.
* sThreadCreationLock protects thread creation and removal and list of
threads in team.
* Team::signal_lock and Team::time_lock protect list of threads in team
as well.
* Scheduler uses its own internal locking.


# 24df6592 11-Jun-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged signals-merge branch into trunk with the following changes:
* Reorganized the kernel locking related to threads and teams.
* We now discriminate correctly between process and thread signals. Signal
handlers have been moved to teams. Fixes #5679.
* Implemented real-time signal support, including signal queuing, SA_SIGINFO
support, sigqueue(), sigwaitinfo(), sigtimedwait(), waitid(), and the addition
of the real-time signal range. Closes #1935 and #2695.
* Gave SIGBUS a separate signal number. Fixes #6704.
* Implemented <time.h> clock and timer support, and fixed/completed alarm() and
[set]itimer(). Closes #5682.
* Implemented support for thread cancellation. Closes #5686.
* Moved send_signal() from <signal.h> to <OS.h>. Fixes #7554.
* Lots over smaller more or less related changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42116 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 4535495d 10-Jan-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged the signals branch into trunk, with these changes:
* The team and thread kernel structures have been renamed to Team and Thread
respectively and moved into the new BKernel namespace.
* Several (kernel add-on) sources have been converted from C to C++ since
private kernel headers are included that are no longer C compatible.

Changes after merging:
* Fixed gcc 2 build (warnings mainly in the scary firewire bus manager).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40196 a95241bf-73f2-0310-859d-f6bbb57e9c96


# af983c17 03-Dec-2009 Colin Günther <coling@gmx.de>

Coding style cleanups. Thanks axeld.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34462 a95241bf-73f2-0310-859d-f6bbb57e9c96


# f5251d5b 02-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

Added comment regarding use restriction.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34460 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 1581b764 02-Dec-2009 Colin Günther <coling@gmx.de>

* Adding static Notify{One,All} functions. This allows a cleaner implementation
of the condition variable and synchronization subsystem of the freebsd compat
layer which will be committed next.
* Also there was a discussion about adding these functions on the commit
mailing list. The mail in http://www.freelists.org/post/haiku-commits/r34395-in-haikutrunksrclibscompatfreebsd-network-compatsys,3
is a good sum up of it (need to scroll somewhat down, though).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34458 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5ee1f125 21-Oct-2009 Michael Lotz <mmlr@mlotz.ch>

Make use of the wait status field so it can be provided in Notify() and then
read out in the ConditionVariableEntry::WaitStatus(). That way you can notify
with a specific status that can be read out on the other end.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33718 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5147963d 26-Jul-2009 Stephan Aßmus <superstippi@gmx.de>

headers/private/kernel/util/OpenHashTable.h, Hugo's version, is a bit nicer than
Tracker's OpenHashTable.h which it should eventually replace. We've renamed the
class to BOpenHashTable and changed the interface slightly so that HashTableLink
became superfluous.
Adapted all the code that used it. Since the OpenHashTables no longer clash,
this should fix the GCC4 build.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31791 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5ea5f51d 22-Jun-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

Changed ConditionVariable from class to struct to make it more C-friendly.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31191 a95241bf-73f2-0310-859d-f6bbb57e9c96


# d5488b77 03-Sep-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

Added ConditionVariable::ObjectType() getter.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27303 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5c99d639 22-Jul-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged branch haiku/branches/developer/bonefish/vm into trunk. This
introduces the following relevant changes:
* VMCache:
- Renamed vm_cache to VMCache, merged it with vm_store and made it a
C++ class with virtual methods (replacing the store operations).
Turned the different store implementations into subclasses.
- Introduced MergeStore() callback, changed semantics of Commit().
- Changed locking and referencing semantics. A reference can only be
acquired/released with the cache locked. An unreferenced cache is
deleted and a mergeable cache merged when it is unlocked. This
removes the "busy" state of a cache and simplifies the page fault
code.
* Added VMAnonymousCache, which will implement swap support (work by
Zhao Shuai). It is not integrated and used yet, though.
* Enabled the mutex/recursive lock holder asserts.
* Fixed DoublyLinkedList::Swap().
* Generalized the low memory handler to a low resource handler. And made
semaphores and reserved memory handled resources. Made
vm_try_resource_memory() optionally wait (with timeout), and used that
feature to reserve memory for areas.
...


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26572 a95241bf-73f2-0310-859d-f6bbb57e9c96


# cb919155 16-Jul-2008 Axel Dörfler <axeld@pinc-software.de>

bonefish + axeld:
* Removed the superfluous "flags" parameter from ConditionVariable::Add()
that we forgot there when we moved the flags field from
ConditionVariableEntry::Add() to Wait().
* Using this method was therefore not a good idea - only UnixFifo did, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26454 a95241bf-73f2-0310-859d-f6bbb57e9c96


# fbe0c27a 17-May-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

axeld + bonefish:
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


# 023bf5fc 22-Apr-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

* Added support for timeouts.
* 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


# 6cef245e 22-Apr-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

* Detemplatized ConditionVariable{Entry}. Merged them with their
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


# b95f6d47 22-Apr-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

* Introduced a set of functions (thread_prepare_to_block(),
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


# 8db2e374 20-Apr-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

Removed the feature that a thread can wait for more than one condition
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


# bd0689e6 17-Jan-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

Added usage message to "cvar" and "cvars" debugger commands and define
temporary variables.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23596 a95241bf-73f2-0310-859d-f6bbb57e9c96


# d0c2af77 01-Oct-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Addressed a deadlock race condition: Acquiration of condition variable
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


# eee9e86c 28-Sep-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Set default template argument to void, so that one doesn't need to
bother.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22358 a95241bf-73f2-0310-859d-f6bbb57e9c96


# addece20 02-Sep-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

* Fixed incorrect check in condition_variable_interrupt_thread().
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


# c9e5503e 27-Aug-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Notify*() and Unpublish() acquire the threads lock. So they need to know
whether the lock is already being held.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22087 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 4ed79176 27-Aug-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Wait() returns a status_t now, which can be B_OK (condition variable
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


# ff308b0b 26-Aug-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Condition variables changes:
* 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


# 227402f2 09-Aug-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Added simple condition variables to the kernel. They are a relatively
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


# 03fb2d886830e4dd4b344c56725db59f96733216 07-Nov-2013 Pawel Dziepak <pdziepak@quarnos.org>

kernel: Remove gSchedulerLock

* Thread::scheduler_lock protects thread state, priority, etc.
* sThreadCreationLock protects thread creation and removal and list of
threads in team.
* Team::signal_lock and Team::time_lock protect list of threads in team
as well.
* Scheduler uses its own internal locking.


# 24df65921befcd0ad0c5c7866118f922da61cb96 11-Jun-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged signals-merge branch into trunk with the following changes:
* Reorganized the kernel locking related to threads and teams.
* We now discriminate correctly between process and thread signals. Signal
handlers have been moved to teams. Fixes #5679.
* Implemented real-time signal support, including signal queuing, SA_SIGINFO
support, sigqueue(), sigwaitinfo(), sigtimedwait(), waitid(), and the addition
of the real-time signal range. Closes #1935 and #2695.
* Gave SIGBUS a separate signal number. Fixes #6704.
* Implemented <time.h> clock and timer support, and fixed/completed alarm() and
[set]itimer(). Closes #5682.
* Implemented support for thread cancellation. Closes #5686.
* Moved send_signal() from <signal.h> to <OS.h>. Fixes #7554.
* Lots over smaller more or less related changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42116 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 4535495d80c86e19e2610e7444a4fcefe3e0f8e6 10-Jan-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged the signals branch into trunk, with these changes:
* The team and thread kernel structures have been renamed to Team and Thread
respectively and moved into the new BKernel namespace.
* Several (kernel add-on) sources have been converted from C to C++ since
private kernel headers are included that are no longer C compatible.

Changes after merging:
* Fixed gcc 2 build (warnings mainly in the scary firewire bus manager).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40196 a95241bf-73f2-0310-859d-f6bbb57e9c96


# af983c175d62713b0598366f2fc365ba56d46b26 03-Dec-2009 Colin Günther <coling@gmx.de>

Coding style cleanups. Thanks axeld.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34462 a95241bf-73f2-0310-859d-f6bbb57e9c96


# f5251d5b6036a10d2ad4338c0d0b789644da7b1d 02-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

Added comment regarding use restriction.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34460 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 1581b764e0a14e86671bc5193516eedc621610e9 02-Dec-2009 Colin Günther <coling@gmx.de>

* Adding static Notify{One,All} functions. This allows a cleaner implementation
of the condition variable and synchronization subsystem of the freebsd compat
layer which will be committed next.
* Also there was a discussion about adding these functions on the commit
mailing list. The mail in http://www.freelists.org/post/haiku-commits/r34395-in-haikutrunksrclibscompatfreebsd-network-compatsys,3
is a good sum up of it (need to scroll somewhat down, though).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34458 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5ee1f125e59267d8dce4c22c7d030d0310eebbf3 21-Oct-2009 Michael Lotz <mmlr@mlotz.ch>

Make use of the wait status field so it can be provided in Notify() and then
read out in the ConditionVariableEntry::WaitStatus(). That way you can notify
with a specific status that can be read out on the other end.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33718 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5147963dcd57fefa4f63c484eb88e9eaf4002976 26-Jul-2009 Stephan Aßmus <superstippi@gmx.de>

headers/private/kernel/util/OpenHashTable.h, Hugo's version, is a bit nicer than
Tracker's OpenHashTable.h which it should eventually replace. We've renamed the
class to BOpenHashTable and changed the interface slightly so that HashTableLink
became superfluous.
Adapted all the code that used it. Since the OpenHashTables no longer clash,
this should fix the GCC4 build.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31791 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5ea5f51d84026be4a0264981e735a54a796ce441 22-Jun-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

Changed ConditionVariable from class to struct to make it more C-friendly.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31191 a95241bf-73f2-0310-859d-f6bbb57e9c96


# d5488b7703b0f3995627ad670fc178f84181d78a 03-Sep-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

Added ConditionVariable::ObjectType() getter.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27303 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5c99d639708df9b4e2cc847b38d510149d19ec78 22-Jul-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged branch haiku/branches/developer/bonefish/vm into trunk. This
introduces the following relevant changes:
* VMCache:
- Renamed vm_cache to VMCache, merged it with vm_store and made it a
C++ class with virtual methods (replacing the store operations).
Turned the different store implementations into subclasses.
- Introduced MergeStore() callback, changed semantics of Commit().
- Changed locking and referencing semantics. A reference can only be
acquired/released with the cache locked. An unreferenced cache is
deleted and a mergeable cache merged when it is unlocked. This
removes the "busy" state of a cache and simplifies the page fault
code.
* Added VMAnonymousCache, which will implement swap support (work by
Zhao Shuai). It is not integrated and used yet, though.
* Enabled the mutex/recursive lock holder asserts.
* Fixed DoublyLinkedList::Swap().
* Generalized the low memory handler to a low resource handler. And made
semaphores and reserved memory handled resources. Made
vm_try_resource_memory() optionally wait (with timeout), and used that
feature to reserve memory for areas.
...


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26572 a95241bf-73f2-0310-859d-f6bbb57e9c96


# cb9191556c39d4321b6dc700532eb74f598d166d 16-Jul-2008 Axel Dörfler <axeld@pinc-software.de>

bonefish + axeld:
* Removed the superfluous "flags" parameter from ConditionVariable::Add()
that we forgot there when we moved the flags field from
ConditionVariableEntry::Add() to Wait().
* Using this method was therefore not a good idea - only UnixFifo did, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26454 a95241bf-73f2-0310-859d-f6bbb57e9c96


# fbe0c27a94fff9dff7c42e12ee96f789b314c746 17-May-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

axeld + bonefish:
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


# 023bf5fcda8c37eb8e295784608ce818384a0ca5 22-Apr-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

* Added support for timeouts.
* 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


# 6cef245eca821584f07f5a13558f51ec586852e8 22-Apr-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

* Detemplatized ConditionVariable{Entry}. Merged them with their
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


# b95f6d4710855a27bec41b6fae2b064347780173 22-Apr-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

* Introduced a set of functions (thread_prepare_to_block(),
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


# 8db2e374929b7ac0cf11a064c93fefff5926588d 20-Apr-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

Removed the feature that a thread can wait for more than one condition
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


# bd0689e66829b9e05545c831cc817ba069224acc 17-Jan-2008 Ingo Weinhold <ingo_weinhold@gmx.de>

Added usage message to "cvar" and "cvars" debugger commands and define
temporary variables.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23596 a95241bf-73f2-0310-859d-f6bbb57e9c96


# d0c2af771393d353dde1f0375d1edbf1f410be50 01-Oct-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Addressed a deadlock race condition: Acquiration of condition variable
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


# eee9e86c6bd3c49517287f068832a68e387f2889 28-Sep-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Set default template argument to void, so that one doesn't need to
bother.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22358 a95241bf-73f2-0310-859d-f6bbb57e9c96


# addece2001c2683709aec70ec48f91fa142c0752 02-Sep-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

* Fixed incorrect check in condition_variable_interrupt_thread().
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


# c9e5503e5e2490c4e7e9e0caa80fcc47a1c6f4df 27-Aug-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Notify*() and Unpublish() acquire the threads lock. So they need to know
whether the lock is already being held.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22087 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 4ed7917682c43a005d86857889895a63374b66ea 27-Aug-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Wait() returns a status_t now, which can be B_OK (condition variable
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


# ff308b0b491531f2f3b5d22244d7ac5904133e61 26-Aug-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Condition variables changes:
* 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


# 227402f2bfd4187053a07abd674464cf88885a3d 09-Aug-2007 Ingo Weinhold <ingo_weinhold@gmx.de>

Added simple condition variables to the kernel. They are a relatively
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