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Diffstat (limited to 'sys/dev/raidframe/rf_cvscan.h')
| -rw-r--r-- | sys/dev/raidframe/rf_cvscan.h | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/sys/dev/raidframe/rf_cvscan.h b/sys/dev/raidframe/rf_cvscan.h new file mode 100644 index 0000000..7f536a8 --- /dev/null +++ b/sys/dev/raidframe/rf_cvscan.h @@ -0,0 +1,85 @@ +/* $FreeBSD$ */ +/* $NetBSD: rf_cvscan.h,v 1.3 1999/02/05 00:06:07 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. +*/ + +#ifndef _RF__RF_CVSCAN_H_ +#define _RF__RF_CVSCAN_H_ + +#include <dev/raidframe/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_ */ |
