97 lines
3.2 KiB
C
97 lines
3.2 KiB
C
|
/* $NetBSD: rf_cvscan.h,v 1.1 1998/11/13 04:20:27 oster Exp $ */
|
||
|
|
/*
|
||
|
|
* Copyright (c) 1995 Carnegie-Mellon University.
|
||
|
|
* All rights reserved.
|
||
|
|
*
|
||
|
|
* Author: Mark Holland
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*
|
||
|
|
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
||
|
|
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
|
||
|
|
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
||
|
|
*
|
||
|
|
* Carnegie Mellon requests users of this software to return to
|
||
|
|
*
|
||
|
|
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
||
|
|
* School of Computer Science
|
||
|
|
* Carnegie Mellon University
|
||
|
|
* Pittsburgh PA 15213-3890
|
||
|
|
*
|
||
|
|
* any improvements or extensions that they make and grant Carnegie the
|
||
|
|
* rights to redistribute these changes.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
** Disk scheduling by CVSCAN( N, r )
|
||
|
|
**
|
||
|
|
** Given a set of requests, partition them into one set on each
|
||
|
|
** side of the current arm position. The trick is to pick which
|
||
|
|
** side you are going to service next; once a side is picked you will
|
||
|
|
** service the closest request.
|
||
|
|
** Let there be n1 requests on one side and n2 requests on the other
|
||
|
|
** side. If one of n1 or n2 is zero, select the other side.
|
||
|
|
** If both n1 and n2 are nonzero, select a "range" for examination
|
||
|
|
** that is N' = min( n1, n2, N ). Average the distance from the
|
||
|
|
** current position to the nearest N' requests on each side giving
|
||
|
|
** d1 and d2.
|
||
|
|
** Suppose the last decision was to move toward set 2, then the
|
||
|
|
** current direction is toward set 2, and you will only switch to set
|
||
|
|
** 1 if d1+R < d2 where R is r*(total number of cylinders), r in [0,1].
|
||
|
|
**
|
||
|
|
** I extend this by applying only to the set of requests that all
|
||
|
|
** share the same, highest priority level.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* :
|
||
|
|
* Log: rf_cvscan.h,v
|
||
|
|
* Revision 1.3 1996/06/07 22:26:27 jimz
|
||
|
|
* type-ify which_ru (RF_ReconUnitNum_t)
|
||
|
|
*
|
||
|
|
* Revision 1.2 1996/06/07 21:33:04 jimz
|
||
|
|
* begin using consistent types for sector numbers,
|
||
|
|
* stripe numbers, row+col numbers, recon unit numbers
|
||
|
|
*
|
||
|
|
* Revision 1.1 1996/06/05 19:17:40 jimz
|
||
|
|
* Initial revision
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef _RF__RF_CVSCAN_H_
|
||
|
|
#define _RF__RF_CVSCAN_H_
|
||
|
|
|
||
|
|
#include "rf_diskqueue.h"
|
||
|
|
|
||
|
|
typedef enum RF_CvscanArmDir_e {
|
||
|
|
rf_cvscan_LEFT,
|
||
|
|
rf_cvscan_RIGHT
|
||
|
|
} RF_CvscanArmDir_t;
|
||
|
|
|
||
|
|
typedef struct RF_CvscanHeader_s {
|
||
|
|
long range_for_avg; /* CVSCAN param N */
|
||
|
|
long change_penalty; /* CVSCAN param R */
|
||
|
|
RF_CvscanArmDir_t direction;
|
||
|
|
RF_SectorNum_t cur_block;
|
||
|
|
int nxt_priority;
|
||
|
|
RF_DiskQueueData_t *left;
|
||
|
|
int left_cnt;
|
||
|
|
RF_DiskQueueData_t *right;
|
||
|
|
int right_cnt;
|
||
|
|
RF_DiskQueueData_t *burner;
|
||
|
|
} RF_CvscanHeader_t;
|
||
|
|
|
||
|
|
int rf_CvscanConfigure(void);
|
||
|
|
void *rf_CvscanCreate(RF_SectorCount_t sect_per_disk,
|
||
|
|
RF_AllocListElem_t *cl_list, RF_ShutdownList_t **listp);
|
||
|
|
void rf_CvscanEnqueue(void *qptr, RF_DiskQueueData_t *req, int priority);
|
||
|
|
RF_DiskQueueData_t *rf_CvscanDequeue(void *qptr);
|
||
|
|
RF_DiskQueueData_t *rf_CvscanPeek(void *qptr);
|
||
|
|
int rf_CvscanPromote(void *qptr, RF_StripeNum_t parityStripeID,
|
||
|
|
RF_ReconUnitNum_t which_ru);
|
||
|
|
|
||
|
|
#endif /* !_RF__RF_CVSCAN_H_ */
|