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/* $OpenBSD: rf_fifo.c,v 1.5 2000/08/08 16:07:41 peter Exp $ */
/* $NetBSD: rf_fifo.c,v 1.5 2000/03/04 03:27:13 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.
*/
/***************************************************
*
* rf_fifo.c -- prioritized fifo queue code.
* There are only two priority levels: hi and lo.
*
* Aug 4, 1994, adapted from raidSim version (MCH)
*
***************************************************/
#include "rf_types.h"
#include "rf_alloclist.h"
#include "rf_stripelocks.h"
#include "rf_layout.h"
#include "rf_diskqueue.h"
#include "rf_fifo.h"
#include "rf_debugMem.h"
#include "rf_general.h"
#include "rf_options.h"
#include "rf_raid.h"
#include "rf_types.h"
/* just malloc a header, zero it (via calloc), and return it */
/*ARGSUSED*/
void *
rf_FifoCreate(sectPerDisk, clList, listp)
RF_SectorCount_t sectPerDisk;
RF_AllocListElem_t *clList;
RF_ShutdownList_t **listp;
{
RF_FifoHeader_t *q;
RF_CallocAndAdd(q, 1, sizeof(RF_FifoHeader_t), (RF_FifoHeader_t *), clList);
q->hq_count = q->lq_count = 0;
return ((void *) q);
}
void
rf_FifoEnqueue(q_in, elem, priority)
void *q_in;
RF_DiskQueueData_t *elem;
int priority;
{
RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
RF_ASSERT(priority == RF_IO_NORMAL_PRIORITY || priority == RF_IO_LOW_PRIORITY);
elem->next = NULL;
if (priority == RF_IO_NORMAL_PRIORITY) {
if (!q->hq_tail) {
RF_ASSERT(q->hq_count == 0 && q->hq_head == NULL);
q->hq_head = q->hq_tail = elem;
} else {
RF_ASSERT(q->hq_count != 0 && q->hq_head != NULL);
q->hq_tail->next = elem;
q->hq_tail = elem;
}
q->hq_count++;
} else {
RF_ASSERT(elem->next == NULL);
if (rf_fifoDebug) {
printf("raid%d: fifo: ENQ lopri\n",
elem->raidPtr->raidid);
}
if (!q->lq_tail) {
RF_ASSERT(q->lq_count == 0 && q->lq_head == NULL);
q->lq_head = q->lq_tail = elem;
} else {
RF_ASSERT(q->lq_count != 0 && q->lq_head != NULL);
q->lq_tail->next = elem;
q->lq_tail = elem;
}
q->lq_count++;
}
if ((q->hq_count + q->lq_count) != elem->queue->queueLength) {
printf("Queue lengths differ!: %d %d %d\n",
q->hq_count, q->lq_count, (int) elem->queue->queueLength);
printf("%d %d %d %d\n",
(int) elem->queue->numOutstanding,
(int) elem->queue->maxOutstanding,
(int) elem->queue->row,
(int) elem->queue->col);
}
RF_ASSERT((q->hq_count + q->lq_count) == elem->queue->queueLength);
}
RF_DiskQueueData_t *
rf_FifoDequeue(q_in)
void *q_in;
{
RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
RF_DiskQueueData_t *nd;
RF_ASSERT(q);
if (q->hq_head) {
RF_ASSERT(q->hq_count != 0 && q->hq_tail != NULL);
nd = q->hq_head;
q->hq_head = q->hq_head->next;
if (!q->hq_head)
q->hq_tail = NULL;
nd->next = NULL;
q->hq_count--;
} else
if (q->lq_head) {
RF_ASSERT(q->lq_count != 0 && q->lq_tail != NULL);
nd = q->lq_head;
q->lq_head = q->lq_head->next;
if (!q->lq_head)
q->lq_tail = NULL;
nd->next = NULL;
q->lq_count--;
if (rf_fifoDebug) {
printf("raid%d: fifo: DEQ lopri %lx\n",
nd->raidPtr->raidid, (long) nd);
}
} else {
RF_ASSERT(q->hq_count == 0 && q->lq_count == 0 && q->hq_tail == NULL && q->lq_tail == NULL);
nd = NULL;
}
return (nd);
}
/* Return ptr to item at head of queue. Used to examine request
* info without actually dequeueing the request.
*/
RF_DiskQueueData_t *
rf_FifoPeek(void *q_in)
{
RF_DiskQueueData_t *headElement = NULL;
RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
RF_ASSERT(q);
if (q->hq_head)
headElement = q->hq_head;
else
if (q->lq_head)
headElement = q->lq_head;
return (headElement);
}
/* We sometimes need to promote a low priority access to a regular priority access.
* Currently, this is only used when the user wants to write a stripe which is currently
* under reconstruction.
* This routine will promote all accesses tagged with the indicated parityStripeID from
* the low priority queue to the end of the normal priority queue.
* We assume the queue is locked upon entry.
*/
int
rf_FifoPromote(q_in, parityStripeID, which_ru)
void *q_in;
RF_StripeNum_t parityStripeID;
RF_ReconUnitNum_t which_ru;
{
RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
RF_DiskQueueData_t *lp = q->lq_head, *pt = NULL; /* lp = lo-pri queue
* pointer, pt = trailer */
int retval = 0;
while (lp) {
/* search for the indicated parity stripe in the low-pri queue */
if (lp->parityStripeID == parityStripeID && lp->which_ru == which_ru) {
/* printf("FifoPromote: promoting access for psid
* %ld\n",parityStripeID); */
if (pt)
pt->next = lp->next; /* delete an entry other
* than the first */
else
q->lq_head = lp->next; /* delete the head entry */
if (!q->lq_head)
q->lq_tail = NULL; /* we deleted the only
* entry */
else
if (lp == q->lq_tail)
q->lq_tail = pt; /* we deleted the tail
* entry */
lp->next = NULL;
q->lq_count--;
if (q->hq_tail) {
q->hq_tail->next = lp;
q->hq_tail = lp;
}
/* append to hi-priority queue */
else {
q->hq_head = q->hq_tail = lp;
}
q->hq_count++;
/* UpdateShortestSeekFinishTimeForced(lp->requestPtr,
* lp->diskState); *//* deal with this later, if ever */
lp = (pt) ? pt->next : q->lq_head; /* reset low-pri pointer
* and continue */
retval++;
} else {
pt = lp;
lp = lp->next;
}
}
/* sanity check. delete this if you ever put more than one entry in
* the low-pri queue */
RF_ASSERT(retval == 0 || retval == 1);
return (retval);
}
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