NetBSD-5.0.2/sys/dev/raidframe/rf_diskqueue.c
/* $NetBSD: rf_diskqueue.c,v 1.51 2008/06/17 14:53:11 reinoud 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.
*/
/****************************************************************************
*
* rf_diskqueue.c -- higher-level disk queue code
*
* the routines here are a generic wrapper around the actual queueing
* routines. The code here implements thread scheduling, synchronization,
* and locking ops (see below) on top of the lower-level queueing code.
*
* to support atomic RMW, we implement "locking operations". When a
* locking op is dispatched to the lower levels of the driver, the
* queue is locked, and no further I/Os are dispatched until the queue
* receives & completes a corresponding "unlocking operation". This
* code relies on the higher layers to guarantee that a locking op
* will always be eventually followed by an unlocking op. The model
* is that the higher layers are structured so locking and unlocking
* ops occur in pairs, i.e. an unlocking op cannot be generated until
* after a locking op reports completion. There is no good way to
* check to see that an unlocking op "corresponds" to the op that
* currently has the queue locked, so we make no such attempt. Since
* by definition there can be only one locking op outstanding on a
* disk, this should not be a problem.
*
* In the kernel, we allow multiple I/Os to be concurrently dispatched
* to the disk driver. In order to support locking ops in this
* environment, when we decide to do a locking op, we stop dispatching
* new I/Os and wait until all dispatched I/Os have completed before
* dispatching the locking op.
*
* Unfortunately, the code is different in the 3 different operating
* states (user level, kernel, simulator). In the kernel, I/O is
* non-blocking, and we have no disk threads to dispatch for us.
* Therefore, we have to dispatch new I/Os to the scsi driver at the
* time of enqueue, and also at the time of completion. At user
* level, I/O is blocking, and so only the disk threads may dispatch
* I/Os. Thus at user level, all we can do at enqueue time is enqueue
* and wake up the disk thread to do the dispatch.
*
****************************************************************************/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rf_diskqueue.c,v 1.51 2008/06/17 14:53:11 reinoud Exp $");
#include <dev/raidframe/raidframevar.h>
#include "rf_threadstuff.h"
#include "rf_raid.h"
#include "rf_diskqueue.h"
#include "rf_alloclist.h"
#include "rf_acctrace.h"
#include "rf_etimer.h"
#include "rf_general.h"
#include "rf_debugprint.h"
#include "rf_shutdown.h"
#include "rf_cvscan.h"
#include "rf_sstf.h"
#include "rf_fifo.h"
#include "rf_kintf.h"
static void rf_ShutdownDiskQueueSystem(void *);
#ifndef RF_DEBUG_DISKQUEUE
#define RF_DEBUG_DISKQUEUE 0
#endif
#if RF_DEBUG_DISKQUEUE
#define Dprintf1(s,a) if (rf_queueDebug) rf_debug_printf(s,(void *)((unsigned long)a),NULL,NULL,NULL,NULL,NULL,NULL,NULL)
#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)
#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)
#else
#define Dprintf1(s,a)
#define Dprintf2(s,a,b)
#define Dprintf3(s,a,b,c)
#endif
/*****************************************************************************
*
* the disk queue switch defines all the functions used in the
* different queueing disciplines queue ID, init routine, enqueue
* routine, dequeue routine
*
****************************************************************************/
static const RF_DiskQueueSW_t diskqueuesw[] = {
{"fifo", /* FIFO */
rf_FifoCreate,
rf_FifoEnqueue,
rf_FifoDequeue,
rf_FifoPeek,
rf_FifoPromote},
{"cvscan", /* cvscan */
rf_CvscanCreate,
rf_CvscanEnqueue,
rf_CvscanDequeue,
rf_CvscanPeek,
rf_CvscanPromote},
{"sstf", /* shortest seek time first */
rf_SstfCreate,
rf_SstfEnqueue,
rf_SstfDequeue,
rf_SstfPeek,
rf_SstfPromote},
{"scan", /* SCAN (two-way elevator) */
rf_ScanCreate,
rf_SstfEnqueue,
rf_ScanDequeue,
rf_ScanPeek,
rf_SstfPromote},
{"cscan", /* CSCAN (one-way elevator) */
rf_CscanCreate,
rf_SstfEnqueue,
rf_CscanDequeue,
rf_CscanPeek,
rf_SstfPromote},
};
#define NUM_DISK_QUEUE_TYPES (sizeof(diskqueuesw)/sizeof(RF_DiskQueueSW_t))
#define RF_MAX_FREE_DQD 256
#define RF_MIN_FREE_DQD 64
#include <sys/buf.h>
/* configures a single disk queue */
int
rf_ConfigureDiskQueue(RF_Raid_t *raidPtr, RF_DiskQueue_t *diskqueue,
RF_RowCol_t c, const RF_DiskQueueSW_t *p,
RF_SectorCount_t sectPerDisk, dev_t dev,
int maxOutstanding, RF_ShutdownList_t **listp,
RF_AllocListElem_t *clList)
{
diskqueue->col = c;
diskqueue->qPtr = p;
diskqueue->qHdr = (p->Create) (sectPerDisk, clList, listp);
diskqueue->dev = dev;
diskqueue->numOutstanding = 0;
diskqueue->queueLength = 0;
diskqueue->maxOutstanding = maxOutstanding;
diskqueue->curPriority = RF_IO_NORMAL_PRIORITY;
diskqueue->nextLockingOp = NULL;
diskqueue->flags = 0;
diskqueue->raidPtr = raidPtr;
diskqueue->rf_cinfo = &raidPtr->raid_cinfo[c];
rf_mutex_init(&diskqueue->mutex);
diskqueue->cond = 0;
return (0);
}
static void
rf_ShutdownDiskQueueSystem(void *ignored)
{
pool_destroy(&rf_pools.dqd);
}
int
rf_ConfigureDiskQueueSystem(RF_ShutdownList_t **listp)
{
rf_pool_init(&rf_pools.dqd, sizeof(RF_DiskQueueData_t),
"rf_dqd_pl", RF_MIN_FREE_DQD, RF_MAX_FREE_DQD);
rf_ShutdownCreate(listp, rf_ShutdownDiskQueueSystem, NULL);
return (0);
}
int
rf_ConfigureDiskQueues(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr,
RF_Config_t *cfgPtr)
{
RF_DiskQueue_t *diskQueues, *spareQueues;
const RF_DiskQueueSW_t *p;
RF_RowCol_t r,c;
int rc, i;
raidPtr->maxQueueDepth = cfgPtr->maxOutstandingDiskReqs;
for (p = NULL, i = 0; i < NUM_DISK_QUEUE_TYPES; i++) {
if (!strcmp(diskqueuesw[i].queueType, cfgPtr->diskQueueType)) {
p = &diskqueuesw[i];
break;
}
}
if (p == NULL) {
RF_ERRORMSG2("Unknown queue type \"%s\". Using %s\n", cfgPtr->diskQueueType, diskqueuesw[0].queueType);
p = &diskqueuesw[0];
}
raidPtr->qType = p;
RF_MallocAndAdd(diskQueues,
(raidPtr->numCol + RF_MAXSPARE) *
sizeof(RF_DiskQueue_t), (RF_DiskQueue_t *),
raidPtr->cleanupList);
if (diskQueues == NULL)
return (ENOMEM);
raidPtr->Queues = diskQueues;
for (c = 0; c < raidPtr->numCol; c++) {
rc = rf_ConfigureDiskQueue(raidPtr, &diskQueues[c],
c, p,
raidPtr->sectorsPerDisk,
raidPtr->Disks[c].dev,
cfgPtr->maxOutstandingDiskReqs,
listp, raidPtr->cleanupList);
if (rc)
return (rc);
}
spareQueues = &raidPtr->Queues[raidPtr->numCol];
for (r = 0; r < raidPtr->numSpare; r++) {
rc = rf_ConfigureDiskQueue(raidPtr, &spareQueues[r],
raidPtr->numCol + r, p,
raidPtr->sectorsPerDisk,
raidPtr->Disks[raidPtr->numCol + r].dev,
cfgPtr->maxOutstandingDiskReqs, listp,
raidPtr->cleanupList);
if (rc)
return (rc);
}
return (0);
}
/* Enqueue a disk I/O
*
* Unfortunately, we have to do things differently in the different
* environments (simulator, user-level, kernel).
* At user level, all I/O is blocking, so we have 1 or more threads/disk
* and the thread that enqueues is different from the thread that dequeues.
* In the kernel, I/O is non-blocking and so we'd like to have multiple
* I/Os outstanding on the physical disks when possible.
*
* when any request arrives at a queue, we have two choices:
* dispatch it to the lower levels
* queue it up
*
* kernel rules for when to do what:
* locking request: queue empty => dispatch and lock queue,
* else queue it
* unlocking req : always dispatch it
* normal req : queue empty => dispatch it & set priority
* queue not full & priority is ok => dispatch it
* else queue it
*
* user-level rules:
* always enqueue. In the special case of an unlocking op, enqueue
* in a special way that will cause the unlocking op to be the next
* thing dequeued.
*
* simulator rules:
* Do the same as at user level, with the sleeps and wakeups suppressed.
*/
void
rf_DiskIOEnqueue(RF_DiskQueue_t *queue, RF_DiskQueueData_t *req, int pri)
{
RF_ETIMER_START(req->qtime);
RF_ASSERT(req->type == RF_IO_TYPE_NOP || req->numSector);
req->priority = pri;
#if RF_DEBUG_DISKQUEUE
if (rf_queueDebug && (req->numSector == 0)) {
printf("Warning: Enqueueing zero-sector access\n");
}
#endif
/*
* kernel
*/
RF_LOCK_QUEUE_MUTEX(queue, "DiskIOEnqueue");
/* locking request */
if (RF_LOCKING_REQ(req)) {
if (RF_QUEUE_EMPTY(queue)) {
Dprintf2("Dispatching pri %d locking op to c %d (queue empty)\n", pri, queue->col);
RF_LOCK_QUEUE(queue);
rf_DispatchKernelIO(queue, req);
} else {
queue->queueLength++; /* increment count of number
* of requests waiting in this
* queue */
Dprintf2("Enqueueing pri %d locking op to c %d (queue not empty)\n", pri, queue->col);
req->queue = (void *) queue;
(queue->qPtr->Enqueue) (queue->qHdr, req, pri);
}
}
/* unlocking request */
else
if (RF_UNLOCKING_REQ(req)) { /* we'll do the actual unlock
* when this I/O completes */
Dprintf2("Dispatching pri %d unlocking op to c %d\n", pri, queue->col);
RF_ASSERT(RF_QUEUE_LOCKED(queue));
rf_DispatchKernelIO(queue, req);
}
/* normal request */
else
if (RF_OK_TO_DISPATCH(queue, req)) {
Dprintf2("Dispatching pri %d regular op to c %d (ok to dispatch)\n", pri, queue->col);
rf_DispatchKernelIO(queue, req);
} else {
queue->queueLength++; /* increment count of
* number of requests
* waiting in this queue */
Dprintf2("Enqueueing pri %d regular op to c %d (not ok to dispatch)\n", pri, queue->col);
req->queue = (void *) queue;
(queue->qPtr->Enqueue) (queue->qHdr, req, pri);
}
RF_UNLOCK_QUEUE_MUTEX(queue, "DiskIOEnqueue");
}
/* get the next set of I/Os started, kernel version only */
void
rf_DiskIOComplete(RF_DiskQueue_t *queue, RF_DiskQueueData_t *req, int status)
{
int done = 0;
RF_LOCK_QUEUE_MUTEX(queue, "DiskIOComplete");
/* unlock the queue: (1) after an unlocking req completes (2) after a
* locking req fails */
if (RF_UNLOCKING_REQ(req) || (RF_LOCKING_REQ(req) && status)) {
Dprintf1("DiskIOComplete: unlocking queue at c %d\n", queue->col);
RF_ASSERT(RF_QUEUE_LOCKED(queue));
RF_UNLOCK_QUEUE(queue);
}
queue->numOutstanding--;
RF_ASSERT(queue->numOutstanding >= 0);
/* dispatch requests to the disk until we find one that we can't. */
/* no reason to continue once we've filled up the queue */
/* no reason to even start if the queue is locked */
while (!done && !RF_QUEUE_FULL(queue) && !RF_QUEUE_LOCKED(queue)) {
if (queue->nextLockingOp) {
req = queue->nextLockingOp;
queue->nextLockingOp = NULL;
Dprintf2("DiskIOComplete: a pri %d locking req was pending at c %d\n", req->priority, queue->col);
} else {
req = (queue->qPtr->Dequeue) (queue->qHdr);
if (req != NULL) {
Dprintf2("DiskIOComplete: extracting pri %d req from queue at c %d\n", req->priority, queue->col);
} else {
Dprintf1("DiskIOComplete: no more requests to extract.\n", "");
}
}
if (req) {
queue->queueLength--; /* decrement count of number
* of requests waiting in this
* queue */
RF_ASSERT(queue->queueLength >= 0);
}
if (!req)
done = 1;
else
if (RF_LOCKING_REQ(req)) {
if (RF_QUEUE_EMPTY(queue)) { /* dispatch it */
Dprintf2("DiskIOComplete: dispatching pri %d locking req to c %d (queue empty)\n", req->priority, queue->col);
RF_LOCK_QUEUE(queue);
rf_DispatchKernelIO(queue, req);
done = 1;
} else { /* put it aside to wait for
* the queue to drain */
Dprintf2("DiskIOComplete: postponing pri %d locking req to c %d\n", req->priority, queue->col);
RF_ASSERT(queue->nextLockingOp == NULL);
queue->nextLockingOp = req;
done = 1;
}
} else
if (RF_UNLOCKING_REQ(req)) { /* should not happen:
* unlocking ops should
* not get queued */
RF_ASSERT(RF_QUEUE_LOCKED(queue)); /* support it anyway for
* the future */
Dprintf2("DiskIOComplete: dispatching pri %d unl req to c %d (SHOULD NOT SEE THIS)\n", req->priority, queue->col);
rf_DispatchKernelIO(queue, req);
done = 1;
} else
if (RF_OK_TO_DISPATCH(queue, req)) {
Dprintf2("DiskIOComplete: dispatching pri %d regular req to c %d (ok to dispatch)\n", req->priority, queue->col);
rf_DispatchKernelIO(queue, req);
} else { /* we can't dispatch it,
* so just re-enqueue
* it. */
/* potential trouble here if
* disk queues batch reqs */
Dprintf2("DiskIOComplete: re-enqueueing pri %d regular req to c %d\n", req->priority, queue->col);
queue->queueLength++;
(queue->qPtr->Enqueue) (queue->qHdr, req, req->priority);
done = 1;
}
}
RF_UNLOCK_QUEUE_MUTEX(queue, "DiskIOComplete");
}
/* promotes accesses tagged with the given parityStripeID from low priority
* to normal priority. This promotion is optional, meaning that a queue
* need not implement it. If there is no promotion routine associated with
* a queue, this routine does nothing and returns -1.
*/
int
rf_DiskIOPromote(RF_DiskQueue_t *queue, RF_StripeNum_t parityStripeID,
RF_ReconUnitNum_t which_ru)
{
int retval;
if (!queue->qPtr->Promote)
return (-1);
RF_LOCK_QUEUE_MUTEX(queue, "DiskIOPromote");
retval = (queue->qPtr->Promote) (queue->qHdr, parityStripeID, which_ru);
RF_UNLOCK_QUEUE_MUTEX(queue, "DiskIOPromote");
return (retval);
}
RF_DiskQueueData_t *
rf_CreateDiskQueueData(RF_IoType_t typ, RF_SectorNum_t ssect,
RF_SectorCount_t nsect, void *bf,
RF_StripeNum_t parityStripeID,
RF_ReconUnitNum_t which_ru,
int (*wakeF) (void *, int), void *arg,
RF_AccTraceEntry_t *tracerec, RF_Raid_t *raidPtr,
RF_DiskQueueDataFlags_t flags, void *kb_proc,
int waitflag)
{
RF_DiskQueueData_t *p;
p = pool_get(&rf_pools.dqd, waitflag);
if (p == NULL)
return (NULL);
memset(p, 0, sizeof(RF_DiskQueueData_t));
if (waitflag == PR_WAITOK) {
p->bp = getiobuf(NULL, true);
} else {
p->bp = getiobuf(NULL, false);
}
if (p->bp == NULL) {
pool_put(&rf_pools.dqd, p);
return (NULL);
}
SET(p->bp->b_cflags, BC_BUSY); /* mark buffer busy */
p->sectorOffset = ssect + rf_protectedSectors;
p->numSector = nsect;
p->type = typ;
p->buf = bf;
p->parityStripeID = parityStripeID;
p->which_ru = which_ru;
p->CompleteFunc = wakeF;
p->argument = arg;
p->next = NULL;
p->tracerec = tracerec;
p->priority = RF_IO_NORMAL_PRIORITY;
p->raidPtr = raidPtr;
p->flags = flags;
p->b_proc = kb_proc;
return (p);
}
void
rf_FreeDiskQueueData(RF_DiskQueueData_t *p)
{
int s;
s = splbio(); /* XXX protect only pool_put, or neither? */
putiobuf(p->bp);
pool_put(&rf_pools.dqd, p);
splx(s);
}