Ingo Weinhold
b95f6d4710
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
53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
/*
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* Copyright 2002-2005, Axel Dörfler, [email protected].
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* Distributed under the terms of the MIT License.
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*
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* Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
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* Distributed under the terms of the NewOS License.
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*/
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#ifndef KERNEL_SEM_H
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#define KERNEL_SEM_H
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#include <OS.h>
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#include <thread.h>
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struct kernel_args;
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struct select_info;
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#ifdef __cplusplus
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extern "C" {
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#endif
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extern status_t sem_init(struct kernel_args *args);
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extern int sem_delete_owned_sems(team_id owner);
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extern int32 sem_used_sems(void);
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extern int32 sem_max_sems(void);
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extern status_t select_sem(int32 object, struct select_info *info, bool kernel);
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extern status_t deselect_sem(int32 object, struct select_info *info,
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bool kernel);
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extern sem_id create_sem_etc(int32 count, const char *name, team_id owner);
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/* user calls */
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sem_id _user_create_sem(int32 count, const char *name);
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status_t _user_delete_sem(sem_id id);
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status_t _user_acquire_sem(sem_id id);
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status_t _user_acquire_sem_etc(sem_id id, int32 count, uint32 flags, bigtime_t timeout);
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status_t _user_switch_sem(sem_id releaseSem, sem_id id);
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status_t _user_switch_sem_etc(sem_id releaseSem, sem_id id, int32 count, uint32 flags, bigtime_t timeout);
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status_t _user_release_sem(sem_id id);
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status_t _user_release_sem_etc(sem_id id, int32 count, uint32 flags);
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status_t _user_get_sem_count(sem_id id, int32* thread_count);
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status_t _user_get_sem_info(sem_id, struct sem_info *, size_t);
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status_t _user_get_next_sem_info(team_id, int32 *, struct sem_info *, size_t);
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status_t _user_set_sem_owner(sem_id id, team_id team);
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#ifdef __cplusplus
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}
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#endif
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#endif /* KERNEL_SEM_H */
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