413 lines
13 KiB
C
413 lines
13 KiB
C
/* $NetBSD: rf_diskqueue.c,v 1.53 2011/05/05 06:04:09 mrg Exp $ */
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/*
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* Copyright (c) 1995 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Author: Mark Holland
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/****************************************************************************
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*
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* rf_diskqueue.c -- higher-level disk queue code
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*
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* the routines here are a generic wrapper around the actual queueing
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* routines. The code here implements thread scheduling, synchronization,
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* and locking ops (see below) on top of the lower-level queueing code.
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*
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* to support atomic RMW, we implement "locking operations". When a
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* locking op is dispatched to the lower levels of the driver, the
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* queue is locked, and no further I/Os are dispatched until the queue
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* receives & completes a corresponding "unlocking operation". This
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* code relies on the higher layers to guarantee that a locking op
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* will always be eventually followed by an unlocking op. The model
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* is that the higher layers are structured so locking and unlocking
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* ops occur in pairs, i.e. an unlocking op cannot be generated until
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* after a locking op reports completion. There is no good way to
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* check to see that an unlocking op "corresponds" to the op that
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* currently has the queue locked, so we make no such attempt. Since
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* by definition there can be only one locking op outstanding on a
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* disk, this should not be a problem.
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*
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* In the kernel, we allow multiple I/Os to be concurrently dispatched
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* to the disk driver. In order to support locking ops in this
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* environment, when we decide to do a locking op, we stop dispatching
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* new I/Os and wait until all dispatched I/Os have completed before
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* dispatching the locking op.
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*
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* Unfortunately, the code is different in the 3 different operating
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* states (user level, kernel, simulator). In the kernel, I/O is
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* non-blocking, and we have no disk threads to dispatch for us.
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* Therefore, we have to dispatch new I/Os to the scsi driver at the
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* time of enqueue, and also at the time of completion. At user
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* level, I/O is blocking, and so only the disk threads may dispatch
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* I/Os. Thus at user level, all we can do at enqueue time is enqueue
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* and wake up the disk thread to do the dispatch.
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*
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****************************************************************************/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: rf_diskqueue.c,v 1.53 2011/05/05 06:04:09 mrg Exp $");
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#include <dev/raidframe/raidframevar.h>
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#include "rf_threadstuff.h"
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#include "rf_raid.h"
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#include "rf_diskqueue.h"
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#include "rf_alloclist.h"
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#include "rf_acctrace.h"
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#include "rf_etimer.h"
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#include "rf_general.h"
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#include "rf_debugprint.h"
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#include "rf_shutdown.h"
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#include "rf_cvscan.h"
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#include "rf_sstf.h"
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#include "rf_fifo.h"
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#include "rf_kintf.h"
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static void rf_ShutdownDiskQueueSystem(void *);
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#ifndef RF_DEBUG_DISKQUEUE
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#define RF_DEBUG_DISKQUEUE 0
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#endif
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#if RF_DEBUG_DISKQUEUE
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#define Dprintf1(s,a) if (rf_queueDebug) rf_debug_printf(s,(void *)((unsigned long)a),NULL,NULL,NULL,NULL,NULL,NULL,NULL)
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#define Dprintf2(s,a,b) if (rf_queueDebug) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),NULL,NULL,NULL,NULL,NULL,NULL)
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#define Dprintf3(s,a,b,c) if (rf_queueDebug) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),NULL,NULL,NULL,NULL,NULL)
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#else
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#define Dprintf1(s,a)
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#define Dprintf2(s,a,b)
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#define Dprintf3(s,a,b,c)
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#endif
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/*****************************************************************************
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*
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* the disk queue switch defines all the functions used in the
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* different queueing disciplines queue ID, init routine, enqueue
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* routine, dequeue routine
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*
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****************************************************************************/
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static const RF_DiskQueueSW_t diskqueuesw[] = {
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{"fifo", /* FIFO */
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rf_FifoCreate,
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rf_FifoEnqueue,
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rf_FifoDequeue,
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rf_FifoPeek,
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rf_FifoPromote},
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{"cvscan", /* cvscan */
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rf_CvscanCreate,
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rf_CvscanEnqueue,
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rf_CvscanDequeue,
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rf_CvscanPeek,
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rf_CvscanPromote},
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{"sstf", /* shortest seek time first */
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rf_SstfCreate,
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rf_SstfEnqueue,
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rf_SstfDequeue,
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rf_SstfPeek,
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rf_SstfPromote},
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{"scan", /* SCAN (two-way elevator) */
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rf_ScanCreate,
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rf_SstfEnqueue,
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rf_ScanDequeue,
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rf_ScanPeek,
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rf_SstfPromote},
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{"cscan", /* CSCAN (one-way elevator) */
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rf_CscanCreate,
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rf_SstfEnqueue,
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rf_CscanDequeue,
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rf_CscanPeek,
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rf_SstfPromote},
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};
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#define NUM_DISK_QUEUE_TYPES (sizeof(diskqueuesw)/sizeof(RF_DiskQueueSW_t))
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#define RF_MAX_FREE_DQD 256
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#define RF_MIN_FREE_DQD 64
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#include <sys/buf.h>
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/* configures a single disk queue */
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static void
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rf_ShutdownDiskQueue(void *arg)
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{
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RF_DiskQueue_t *diskqueue = arg;
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rf_destroy_mutex2(diskqueue->mutex);
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}
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int
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rf_ConfigureDiskQueue(RF_Raid_t *raidPtr, RF_DiskQueue_t *diskqueue,
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RF_RowCol_t c, const RF_DiskQueueSW_t *p,
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RF_SectorCount_t sectPerDisk, dev_t dev,
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int maxOutstanding, RF_ShutdownList_t **listp,
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RF_AllocListElem_t *clList)
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{
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diskqueue->col = c;
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diskqueue->qPtr = p;
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diskqueue->qHdr = (p->Create) (sectPerDisk, clList, listp);
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diskqueue->dev = dev;
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diskqueue->numOutstanding = 0;
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diskqueue->queueLength = 0;
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diskqueue->maxOutstanding = maxOutstanding;
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diskqueue->curPriority = RF_IO_NORMAL_PRIORITY;
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diskqueue->flags = 0;
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diskqueue->raidPtr = raidPtr;
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diskqueue->rf_cinfo = &raidPtr->raid_cinfo[c];
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rf_init_mutex2(diskqueue->mutex, IPL_VM);
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rf_ShutdownCreate(listp, rf_ShutdownDiskQueue, diskqueue);
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return (0);
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}
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static void
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rf_ShutdownDiskQueueSystem(void *ignored)
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{
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pool_destroy(&rf_pools.dqd);
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}
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int
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rf_ConfigureDiskQueueSystem(RF_ShutdownList_t **listp)
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{
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rf_pool_init(&rf_pools.dqd, sizeof(RF_DiskQueueData_t),
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"rf_dqd_pl", RF_MIN_FREE_DQD, RF_MAX_FREE_DQD);
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rf_ShutdownCreate(listp, rf_ShutdownDiskQueueSystem, NULL);
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return (0);
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}
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int
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rf_ConfigureDiskQueues(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr,
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RF_Config_t *cfgPtr)
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{
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RF_DiskQueue_t *diskQueues, *spareQueues;
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const RF_DiskQueueSW_t *p;
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RF_RowCol_t r,c;
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int rc, i;
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raidPtr->maxQueueDepth = cfgPtr->maxOutstandingDiskReqs;
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for (p = NULL, i = 0; i < NUM_DISK_QUEUE_TYPES; i++) {
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if (!strcmp(diskqueuesw[i].queueType, cfgPtr->diskQueueType)) {
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p = &diskqueuesw[i];
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break;
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}
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}
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if (p == NULL) {
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RF_ERRORMSG2("Unknown queue type \"%s\". Using %s\n", cfgPtr->diskQueueType, diskqueuesw[0].queueType);
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p = &diskqueuesw[0];
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}
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raidPtr->qType = p;
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RF_MallocAndAdd(diskQueues,
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(raidPtr->numCol + RF_MAXSPARE) *
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sizeof(RF_DiskQueue_t), (RF_DiskQueue_t *),
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raidPtr->cleanupList);
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if (diskQueues == NULL)
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return (ENOMEM);
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raidPtr->Queues = diskQueues;
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for (c = 0; c < raidPtr->numCol; c++) {
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rc = rf_ConfigureDiskQueue(raidPtr, &diskQueues[c],
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c, p,
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raidPtr->sectorsPerDisk,
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raidPtr->Disks[c].dev,
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cfgPtr->maxOutstandingDiskReqs,
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listp, raidPtr->cleanupList);
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if (rc)
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return (rc);
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}
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spareQueues = &raidPtr->Queues[raidPtr->numCol];
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for (r = 0; r < raidPtr->numSpare; r++) {
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rc = rf_ConfigureDiskQueue(raidPtr, &spareQueues[r],
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raidPtr->numCol + r, p,
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raidPtr->sectorsPerDisk,
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raidPtr->Disks[raidPtr->numCol + r].dev,
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cfgPtr->maxOutstandingDiskReqs, listp,
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raidPtr->cleanupList);
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if (rc)
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return (rc);
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}
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return (0);
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}
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/* Enqueue a disk I/O
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*
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* In the kernel, I/O is non-blocking and so we'd like to have multiple
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* I/Os outstanding on the physical disks when possible.
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*
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* when any request arrives at a queue, we have two choices:
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* dispatch it to the lower levels
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* queue it up
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*
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* kernel rules for when to do what:
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* unlocking req : always dispatch it
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* normal req : queue empty => dispatch it & set priority
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* queue not full & priority is ok => dispatch it
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* else queue it
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*/
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void
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rf_DiskIOEnqueue(RF_DiskQueue_t *queue, RF_DiskQueueData_t *req, int pri)
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{
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RF_ETIMER_START(req->qtime);
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RF_ASSERT(req->type == RF_IO_TYPE_NOP || req->numSector);
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req->priority = pri;
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#if RF_DEBUG_DISKQUEUE
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if (rf_queueDebug && (req->numSector == 0)) {
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printf("Warning: Enqueueing zero-sector access\n");
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}
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#endif
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RF_LOCK_QUEUE_MUTEX(queue, "DiskIOEnqueue");
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if (RF_OK_TO_DISPATCH(queue, req)) {
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Dprintf2("Dispatching pri %d regular op to c %d (ok to dispatch)\n", pri, queue->col);
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rf_DispatchKernelIO(queue, req);
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} else {
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queue->queueLength++; /* increment count of number of requests waiting in this queue */
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Dprintf2("Enqueueing pri %d regular op to c %d (not ok to dispatch)\n", pri, queue->col);
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req->queue = (void *) queue;
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(queue->qPtr->Enqueue) (queue->qHdr, req, pri);
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}
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RF_UNLOCK_QUEUE_MUTEX(queue, "DiskIOEnqueue");
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}
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/* get the next set of I/Os started */
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void
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rf_DiskIOComplete(RF_DiskQueue_t *queue, RF_DiskQueueData_t *req, int status)
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{
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int done = 0;
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RF_LOCK_QUEUE_MUTEX(queue, "DiskIOComplete");
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queue->numOutstanding--;
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RF_ASSERT(queue->numOutstanding >= 0);
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/* dispatch requests to the disk until we find one that we can't. */
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/* no reason to continue once we've filled up the queue */
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/* no reason to even start if the queue is locked */
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while (!done && !RF_QUEUE_FULL(queue)) {
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req = (queue->qPtr->Dequeue) (queue->qHdr);
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if (req) {
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Dprintf2("DiskIOComplete: extracting pri %d req from queue at c %d\n", req->priority, queue->col);
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queue->queueLength--; /* decrement count of number of requests waiting in this queue */
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RF_ASSERT(queue->queueLength >= 0);
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if (RF_OK_TO_DISPATCH(queue, req)) {
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Dprintf2("DiskIOComplete: dispatching pri %d regular req to c %d (ok to dispatch)\n", req->priority, queue->col);
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rf_DispatchKernelIO(queue, req);
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} else {
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/* we can't dispatch it, so just re-enqueue it.
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potential trouble here if disk queues batch reqs */
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Dprintf2("DiskIOComplete: re-enqueueing pri %d regular req to c %d\n", req->priority, queue->col);
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queue->queueLength++;
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(queue->qPtr->Enqueue) (queue->qHdr, req, req->priority);
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done = 1;
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}
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} else {
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Dprintf1("DiskIOComplete: no more requests to extract.\n", "");
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done = 1;
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}
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}
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RF_UNLOCK_QUEUE_MUTEX(queue, "DiskIOComplete");
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}
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/* promotes accesses tagged with the given parityStripeID from low priority
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* to normal priority. This promotion is optional, meaning that a queue
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* need not implement it. If there is no promotion routine associated with
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* a queue, this routine does nothing and returns -1.
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*/
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int
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rf_DiskIOPromote(RF_DiskQueue_t *queue, RF_StripeNum_t parityStripeID,
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RF_ReconUnitNum_t which_ru)
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{
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int retval;
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if (!queue->qPtr->Promote)
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return (-1);
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RF_LOCK_QUEUE_MUTEX(queue, "DiskIOPromote");
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retval = (queue->qPtr->Promote) (queue->qHdr, parityStripeID, which_ru);
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RF_UNLOCK_QUEUE_MUTEX(queue, "DiskIOPromote");
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return (retval);
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}
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RF_DiskQueueData_t *
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rf_CreateDiskQueueData(RF_IoType_t typ, RF_SectorNum_t ssect,
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RF_SectorCount_t nsect, void *bf,
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RF_StripeNum_t parityStripeID,
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RF_ReconUnitNum_t which_ru,
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int (*wakeF) (void *, int), void *arg,
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RF_AccTraceEntry_t *tracerec, RF_Raid_t *raidPtr,
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RF_DiskQueueDataFlags_t flags, void *kb_proc,
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int waitflag)
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{
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RF_DiskQueueData_t *p;
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p = pool_get(&rf_pools.dqd, waitflag);
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if (p == NULL)
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return (NULL);
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memset(p, 0, sizeof(RF_DiskQueueData_t));
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if (waitflag == PR_WAITOK) {
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p->bp = getiobuf(NULL, true);
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} else {
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p->bp = getiobuf(NULL, false);
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}
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if (p->bp == NULL) {
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pool_put(&rf_pools.dqd, p);
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return (NULL);
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}
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SET(p->bp->b_cflags, BC_BUSY); /* mark buffer busy */
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p->sectorOffset = ssect + rf_protectedSectors;
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p->numSector = nsect;
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p->type = typ;
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p->buf = bf;
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p->parityStripeID = parityStripeID;
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p->which_ru = which_ru;
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p->CompleteFunc = wakeF;
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p->argument = arg;
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p->next = NULL;
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p->tracerec = tracerec;
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p->priority = RF_IO_NORMAL_PRIORITY;
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p->raidPtr = raidPtr;
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p->flags = flags;
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p->b_proc = kb_proc;
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return (p);
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}
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void
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rf_FreeDiskQueueData(RF_DiskQueueData_t *p)
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{
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int s;
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s = splbio(); /* XXX protect only pool_put, or neither? */
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putiobuf(p->bp);
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pool_put(&rf_pools.dqd, p);
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splx(s);
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}
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