6ed00870ab
Abstracts threading from itself a bit, changes the way its queues are handled and does type hiding for that as well. Do alot here due to already required major brain surgery. Threads may now be on a run queue and a wait queue simultaneously so that the expired timer only has to wake the thread but not remove it from the wait queue which simplifies the implicit wake handling. List formats change for wait queues-- doubly-linked, not circular. Timeout queue is now singly-linked. The run queue is still circular as before. Adds a better thread slot allocator that may keep the slot marked as used regardless of the thread state. Assists in dumping special tasks that switch_thread was tasked to perform (blocking tasks). Deletes alot of code yet surprisingly, gets larger than expected. Well, I'm not not minding that for the time being-- omlettes and break a few eggs and all that. Change-Id: I0834d7bb16b2aecb2f63b58886eeda6ae4f29d59
55 lines
2.1 KiB
C
55 lines
2.1 KiB
C
/***************************************************************************
|
|
* __________ __ ___.
|
|
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
|
|
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
|
|
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
|
|
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
|
|
* \/ \/ \/ \/ \/
|
|
* $Id$
|
|
*
|
|
* Copyright (C) 2014 by Michael Sevakis
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
*
|
|
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
* KIND, either express or implied.
|
|
*
|
|
****************************************************************************/
|
|
#ifndef MRSW_LOCK_H
|
|
#define MRSW_LOCK_H
|
|
|
|
#include "thread.h"
|
|
|
|
/* Multi-reader, single-writer object that allows mutltiple readers or a
|
|
* single writer thread access to a critical section.
|
|
*
|
|
* Readers and writers, as with a mutex, may claim the lock recursively for
|
|
* the same type of access they were already granted.
|
|
*
|
|
* Writers are trivially granted read access by ignoring the request; the
|
|
* object is not changed.
|
|
*
|
|
* Reader promotion to writer is NOT supported and a reader attempting write
|
|
* access will result in a deadlock. That could change but for now, be warned.
|
|
*
|
|
* Full priority inheritance is implemented.
|
|
*/
|
|
struct mrsw_lock
|
|
{
|
|
int volatile count; /* counter; >0 = reader(s), <0 = writer */
|
|
struct __wait_queue queue; /* waiter list */
|
|
struct blocker_splay splay; /* priority inheritance/owner info */
|
|
uint8_t rdrecursion[MAXTHREADS]; /* per-thread reader recursion counts */
|
|
IF_COP( struct corelock cl; )
|
|
};
|
|
|
|
void mrsw_init(struct mrsw_lock *mrsw);
|
|
void mrsw_read_acquire(struct mrsw_lock *mrsw);
|
|
void mrsw_read_release(struct mrsw_lock *mrsw);
|
|
void mrsw_write_acquire(struct mrsw_lock *mrsw);
|
|
void mrsw_write_release(struct mrsw_lock *mrsw);
|
|
|
|
#endif /* MRSW_LOCK_H */
|