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/*
* Copyright (c) 1993,1994 The University of Utah and
* the Computer Systems Laboratory (CSL). All rights reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
* IS" CONDITION. THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
* ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* CSL requests users of this software to return to csl-dist@cs.utah.edu any
* improvements that they make and grant CSL redistribution rights.
*
* Author: Bryan Ford, University of Utah CSL
*/
/*
* File: shuttle.h
* Author: Bryan Ford
*
* This file contains definitions for shuttles,
* which handle microscheduling for individual threads.
*
*/
#ifndef _KERN_SHUTTLE_H_
#define _KERN_SHUTTLE_H_
#include <kern/lock.h>
struct Shuttle {
/* XXX must be first in thread */
/*
* NOTE: The runq field in the thread structure has an unusual
* locking protocol. If its value is RUN_QUEUE_NULL, then it is
* locked by the thread_lock, but if its value is something else
* (i.e. a run_queue) then it is locked by that run_queue's lock.
*/
queue_chain_t links; /* current run queue links */
run_queue_t runq; /* run queue p is on SEE BELOW */
/* Next pointer when on a queue */
struct Shuttle *next;
/* Micropriority level */
int priority;
/* General-purpose pointer field whose use depends on what the
thread happens to be doing */
void *message;
int foobar[1];
};
typedef struct Shuttle Shuttle;
/* Exported functions */
/* Machine-dependent code must define the following functions */
#endif /* _KERN_SHUTTLE_H_ */
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