657 lines
16 KiB
C
657 lines
16 KiB
C
/* $FreeBSD$ */
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/* $NetBSD: rf_sstf.c,v 1.6 2001/01/27 20:18:55 oster 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: Jim Zelenka
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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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* sstf.c -- prioritized shortest seek time first disk queueing code
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*
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******************************************************************************/
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#include <dev/raidframe/rf_alloclist.h>
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#include <dev/raidframe/rf_stripelocks.h>
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#include <dev/raidframe/rf_layout.h>
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#include <dev/raidframe/rf_diskqueue.h>
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#include <dev/raidframe/rf_sstf.h>
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#include <dev/raidframe/rf_debugMem.h>
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#include <dev/raidframe/rf_general.h>
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#include <dev/raidframe/rf_options.h>
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#include <dev/raidframe/rf_raid.h>
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#include <dev/raidframe/rf_types.h>
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#define DIR_LEFT 1
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#define DIR_RIGHT 2
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#define DIR_EITHER 3
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#define SNUM_DIFF(_a_,_b_) (((_a_)>(_b_))?((_a_)-(_b_)):((_b_)-(_a_)))
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#define QSUM(_sstfq_) (((_sstfq_)->lopri.qlen)+((_sstfq_)->left.qlen)+((_sstfq_)->right.qlen))
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static void
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do_sstf_ord_q(RF_DiskQueueData_t **,
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RF_DiskQueueData_t **,
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RF_DiskQueueData_t *);
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static RF_DiskQueueData_t *
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closest_to_arm(RF_SstfQ_t *,
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RF_SectorNum_t,
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int *,
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int);
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static void do_dequeue(RF_SstfQ_t *, RF_DiskQueueData_t *);
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static void
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do_sstf_ord_q(queuep, tailp, req)
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RF_DiskQueueData_t **queuep;
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RF_DiskQueueData_t **tailp;
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RF_DiskQueueData_t *req;
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{
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RF_DiskQueueData_t *r, *s;
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if (*queuep == NULL) {
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*queuep = req;
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*tailp = req;
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req->next = NULL;
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req->prev = NULL;
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return;
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}
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if (req->sectorOffset <= (*queuep)->sectorOffset) {
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req->next = *queuep;
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req->prev = NULL;
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(*queuep)->prev = req;
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*queuep = req;
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return;
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}
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if (req->sectorOffset > (*tailp)->sectorOffset) {
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/* optimization */
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r = NULL;
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s = *tailp;
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goto q_at_end;
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}
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for (s = NULL, r = *queuep; r; s = r, r = r->next) {
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if (r->sectorOffset >= req->sectorOffset) {
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/* insert after s, before r */
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RF_ASSERT(s);
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req->next = r;
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r->prev = req;
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s->next = req;
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req->prev = s;
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return;
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}
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}
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q_at_end:
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/* insert after s, at end of queue */
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RF_ASSERT(r == NULL);
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RF_ASSERT(s);
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RF_ASSERT(s == (*tailp));
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req->next = NULL;
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req->prev = s;
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s->next = req;
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*tailp = req;
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}
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/* for removing from head-of-queue */
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#define DO_HEAD_DEQ(_r_,_q_) { \
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_r_ = (_q_)->queue; \
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RF_ASSERT((_r_) != NULL); \
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(_q_)->queue = (_r_)->next; \
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(_q_)->qlen--; \
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if ((_q_)->qlen == 0) { \
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RF_ASSERT((_r_) == (_q_)->qtail); \
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RF_ASSERT((_q_)->queue == NULL); \
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(_q_)->qtail = NULL; \
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} \
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else { \
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RF_ASSERT((_q_)->queue->prev == (_r_)); \
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(_q_)->queue->prev = NULL; \
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} \
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}
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/* for removing from end-of-queue */
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#define DO_TAIL_DEQ(_r_,_q_) { \
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_r_ = (_q_)->qtail; \
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RF_ASSERT((_r_) != NULL); \
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(_q_)->qtail = (_r_)->prev; \
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(_q_)->qlen--; \
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if ((_q_)->qlen == 0) { \
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RF_ASSERT((_r_) == (_q_)->queue); \
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RF_ASSERT((_q_)->qtail == NULL); \
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(_q_)->queue = NULL; \
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} \
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else { \
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RF_ASSERT((_q_)->qtail->next == (_r_)); \
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(_q_)->qtail->next = NULL; \
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} \
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}
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#define DO_BEST_DEQ(_l_,_r_,_q_) { \
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if (SNUM_DIFF((_q_)->queue->sectorOffset,_l_) \
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< SNUM_DIFF((_q_)->qtail->sectorOffset,_l_)) \
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{ \
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DO_HEAD_DEQ(_r_,_q_); \
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} \
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else { \
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DO_TAIL_DEQ(_r_,_q_); \
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} \
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}
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static RF_DiskQueueData_t *
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closest_to_arm(queue, arm_pos, dir, allow_reverse)
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RF_SstfQ_t *queue;
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RF_SectorNum_t arm_pos;
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int *dir;
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int allow_reverse;
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{
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RF_SectorNum_t best_pos_l = 0, this_pos_l = 0, last_pos = 0;
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RF_SectorNum_t best_pos_r = 0, this_pos_r = 0;
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RF_DiskQueueData_t *r, *best_l, *best_r;
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best_r = best_l = NULL;
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for (r = queue->queue; r; r = r->next) {
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if (r->sectorOffset < arm_pos) {
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if (best_l == NULL) {
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best_l = r;
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last_pos = best_pos_l = this_pos_l;
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} else {
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this_pos_l = arm_pos - r->sectorOffset;
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if (this_pos_l < best_pos_l) {
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best_l = r;
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last_pos = best_pos_l = this_pos_l;
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} else {
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last_pos = this_pos_l;
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}
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}
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} else {
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if (best_r == NULL) {
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best_r = r;
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last_pos = best_pos_r = this_pos_r;
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} else {
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this_pos_r = r->sectorOffset - arm_pos;
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if (this_pos_r < best_pos_r) {
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best_r = r;
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last_pos = best_pos_r = this_pos_r;
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} else {
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last_pos = this_pos_r;
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}
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if (this_pos_r > last_pos) {
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/* getting farther away */
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break;
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}
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}
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}
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}
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if ((best_r == NULL) && (best_l == NULL))
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return (NULL);
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if ((*dir == DIR_RIGHT) && best_r)
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return (best_r);
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if ((*dir == DIR_LEFT) && best_l)
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return (best_l);
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if (*dir == DIR_EITHER) {
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if (best_l == NULL)
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return (best_r);
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if (best_r == NULL)
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return (best_l);
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if (best_pos_r < best_pos_l)
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return (best_r);
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else
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return (best_l);
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}
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/*
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* Nothing in the direction we want to go. Reverse or
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* reset the arm. We know we have an I/O in the other
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* direction.
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*/
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if (allow_reverse) {
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if (*dir == DIR_RIGHT) {
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*dir = DIR_LEFT;
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return (best_l);
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} else {
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*dir = DIR_RIGHT;
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return (best_r);
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}
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}
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/*
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* Reset (beginning of queue).
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*/
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RF_ASSERT(*dir == DIR_RIGHT);
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return (queue->queue);
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}
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void *
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rf_SstfCreate(sect_per_disk, cl_list, listp)
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RF_SectorCount_t sect_per_disk;
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RF_AllocListElem_t *cl_list;
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RF_ShutdownList_t **listp;
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{
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RF_Sstf_t *sstfq;
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RF_CallocAndAdd(sstfq, 1, sizeof(RF_Sstf_t), (RF_Sstf_t *), cl_list);
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sstfq->dir = DIR_EITHER;
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sstfq->allow_reverse = 1;
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return ((void *) sstfq);
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}
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void *
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rf_ScanCreate(sect_per_disk, cl_list, listp)
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RF_SectorCount_t sect_per_disk;
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RF_AllocListElem_t *cl_list;
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RF_ShutdownList_t **listp;
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{
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RF_Sstf_t *scanq;
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RF_CallocAndAdd(scanq, 1, sizeof(RF_Sstf_t), (RF_Sstf_t *), cl_list);
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scanq->dir = DIR_RIGHT;
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scanq->allow_reverse = 1;
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return ((void *) scanq);
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}
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void *
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rf_CscanCreate(sect_per_disk, cl_list, listp)
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RF_SectorCount_t sect_per_disk;
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RF_AllocListElem_t *cl_list;
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RF_ShutdownList_t **listp;
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{
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RF_Sstf_t *cscanq;
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RF_CallocAndAdd(cscanq, 1, sizeof(RF_Sstf_t), (RF_Sstf_t *), cl_list);
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cscanq->dir = DIR_RIGHT;
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return ((void *) cscanq);
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}
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void
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rf_SstfEnqueue(qptr, req, priority)
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void *qptr;
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RF_DiskQueueData_t *req;
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int priority;
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{
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RF_Sstf_t *sstfq;
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sstfq = (RF_Sstf_t *) qptr;
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if (priority == RF_IO_LOW_PRIORITY) {
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if (rf_sstfDebug || rf_scanDebug || rf_cscanDebug) {
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RF_DiskQueue_t *dq;
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dq = (RF_DiskQueue_t *) req->queue;
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printf("raid%d: ENQ lopri %d,%d queues are %d,%d,%d\n",
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req->raidPtr->raidid,
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dq->row, dq->col,
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sstfq->left.qlen, sstfq->right.qlen,
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sstfq->lopri.qlen);
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}
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do_sstf_ord_q(&sstfq->lopri.queue, &sstfq->lopri.qtail, req);
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sstfq->lopri.qlen++;
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} else {
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if (req->sectorOffset < sstfq->last_sector) {
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do_sstf_ord_q(&sstfq->left.queue, &sstfq->left.qtail, req);
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sstfq->left.qlen++;
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} else {
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do_sstf_ord_q(&sstfq->right.queue, &sstfq->right.qtail, req);
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sstfq->right.qlen++;
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}
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}
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}
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static void
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do_dequeue(queue, req)
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RF_SstfQ_t *queue;
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RF_DiskQueueData_t *req;
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{
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RF_DiskQueueData_t *req2;
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if (rf_sstfDebug || rf_scanDebug || rf_cscanDebug) {
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printf("raid%d: do_dequeue\n", req->raidPtr->raidid);
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}
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if (req == queue->queue) {
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DO_HEAD_DEQ(req2, queue);
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RF_ASSERT(req2 == req);
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} else
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if (req == queue->qtail) {
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DO_TAIL_DEQ(req2, queue);
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RF_ASSERT(req2 == req);
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} else {
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/* dequeue from middle of list */
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RF_ASSERT(req->next);
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RF_ASSERT(req->prev);
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queue->qlen--;
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req->next->prev = req->prev;
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req->prev->next = req->next;
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req->next = req->prev = NULL;
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}
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}
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RF_DiskQueueData_t *
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rf_SstfDequeue(qptr)
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void *qptr;
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{
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RF_DiskQueueData_t *req = NULL;
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RF_Sstf_t *sstfq;
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sstfq = (RF_Sstf_t *) qptr;
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if (rf_sstfDebug) {
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RF_DiskQueue_t *dq;
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dq = (RF_DiskQueue_t *) req->queue;
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RF_ASSERT(QSUM(sstfq) == dq->queueLength);
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printf("raid%d: sstf: Dequeue %d,%d queues are %d,%d,%d\n",
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req->raidPtr->raidid, dq->row, dq->col,
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sstfq->left.qlen, sstfq->right.qlen, sstfq->lopri.qlen);
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}
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if (sstfq->left.queue == NULL) {
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RF_ASSERT(sstfq->left.qlen == 0);
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if (sstfq->right.queue == NULL) {
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RF_ASSERT(sstfq->right.qlen == 0);
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if (sstfq->lopri.queue == NULL) {
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RF_ASSERT(sstfq->lopri.qlen == 0);
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return (NULL);
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}
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if (rf_sstfDebug) {
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printf("raid%d: sstf: check for close lopri",
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req->raidPtr->raidid);
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}
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req = closest_to_arm(&sstfq->lopri, sstfq->last_sector,
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&sstfq->dir, sstfq->allow_reverse);
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if (rf_sstfDebug) {
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printf("raid%d: sstf: closest_to_arm said %lx",
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req->raidPtr->raidid, (long) req);
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}
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if (req == NULL)
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return (NULL);
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do_dequeue(&sstfq->lopri, req);
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} else {
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DO_BEST_DEQ(sstfq->last_sector, req, &sstfq->right);
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}
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} else {
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if (sstfq->right.queue == NULL) {
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RF_ASSERT(sstfq->right.qlen == 0);
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DO_BEST_DEQ(sstfq->last_sector, req, &sstfq->left);
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} else {
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if (SNUM_DIFF(sstfq->last_sector, sstfq->right.queue->sectorOffset)
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< SNUM_DIFF(sstfq->last_sector, sstfq->left.qtail->sectorOffset)) {
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DO_HEAD_DEQ(req, &sstfq->right);
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} else {
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DO_TAIL_DEQ(req, &sstfq->left);
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}
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}
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}
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RF_ASSERT(req);
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sstfq->last_sector = req->sectorOffset;
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return (req);
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}
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RF_DiskQueueData_t *
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rf_ScanDequeue(qptr)
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void *qptr;
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{
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RF_DiskQueueData_t *req = NULL;
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RF_Sstf_t *scanq;
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scanq = (RF_Sstf_t *) qptr;
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if (rf_scanDebug) {
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RF_DiskQueue_t *dq;
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dq = (RF_DiskQueue_t *) req->queue;
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RF_ASSERT(QSUM(scanq) == dq->queueLength);
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printf("raid%d: scan: Dequeue %d,%d queues are %d,%d,%d\n",
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req->raidPtr->raidid, dq->row, dq->col,
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scanq->left.qlen, scanq->right.qlen, scanq->lopri.qlen);
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}
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if (scanq->left.queue == NULL) {
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RF_ASSERT(scanq->left.qlen == 0);
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if (scanq->right.queue == NULL) {
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RF_ASSERT(scanq->right.qlen == 0);
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if (scanq->lopri.queue == NULL) {
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RF_ASSERT(scanq->lopri.qlen == 0);
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return (NULL);
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}
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req = closest_to_arm(&scanq->lopri, scanq->last_sector,
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&scanq->dir, scanq->allow_reverse);
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if (req == NULL)
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return (NULL);
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do_dequeue(&scanq->lopri, req);
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} else {
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scanq->dir = DIR_RIGHT;
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DO_HEAD_DEQ(req, &scanq->right);
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}
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} else
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if (scanq->right.queue == NULL) {
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RF_ASSERT(scanq->right.qlen == 0);
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RF_ASSERT(scanq->left.queue);
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scanq->dir = DIR_LEFT;
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DO_TAIL_DEQ(req, &scanq->left);
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} else {
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RF_ASSERT(scanq->right.queue);
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RF_ASSERT(scanq->left.queue);
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if (scanq->dir == DIR_RIGHT) {
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DO_HEAD_DEQ(req, &scanq->right);
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} else {
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DO_TAIL_DEQ(req, &scanq->left);
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}
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}
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RF_ASSERT(req);
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scanq->last_sector = req->sectorOffset;
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return (req);
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}
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RF_DiskQueueData_t *
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rf_CscanDequeue(qptr)
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void *qptr;
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{
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RF_DiskQueueData_t *req = NULL;
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RF_Sstf_t *cscanq;
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cscanq = (RF_Sstf_t *) qptr;
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RF_ASSERT(cscanq->dir == DIR_RIGHT);
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if (rf_cscanDebug) {
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RF_DiskQueue_t *dq;
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dq = (RF_DiskQueue_t *) req->queue;
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RF_ASSERT(QSUM(cscanq) == dq->queueLength);
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printf("raid%d: scan: Dequeue %d,%d queues are %d,%d,%d\n",
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req->raidPtr->raidid, dq->row, dq->col,
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cscanq->left.qlen, cscanq->right.qlen,
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cscanq->lopri.qlen);
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}
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if (cscanq->right.queue) {
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DO_HEAD_DEQ(req, &cscanq->right);
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|
} else {
|
|
RF_ASSERT(cscanq->right.qlen == 0);
|
|
if (cscanq->left.queue == NULL) {
|
|
RF_ASSERT(cscanq->left.qlen == 0);
|
|
if (cscanq->lopri.queue == NULL) {
|
|
RF_ASSERT(cscanq->lopri.qlen == 0);
|
|
return (NULL);
|
|
}
|
|
req = closest_to_arm(&cscanq->lopri, cscanq->last_sector,
|
|
&cscanq->dir, cscanq->allow_reverse);
|
|
if (req == NULL)
|
|
return (NULL);
|
|
do_dequeue(&cscanq->lopri, req);
|
|
} else {
|
|
/*
|
|
* There's I/Os to the left of the arm. Swing
|
|
* on back (swap queues).
|
|
*/
|
|
cscanq->right = cscanq->left;
|
|
cscanq->left.qlen = 0;
|
|
cscanq->left.queue = cscanq->left.qtail = NULL;
|
|
DO_HEAD_DEQ(req, &cscanq->right);
|
|
}
|
|
}
|
|
RF_ASSERT(req);
|
|
cscanq->last_sector = req->sectorOffset;
|
|
return (req);
|
|
}
|
|
|
|
RF_DiskQueueData_t *
|
|
rf_SstfPeek(qptr)
|
|
void *qptr;
|
|
{
|
|
RF_DiskQueueData_t *req;
|
|
RF_Sstf_t *sstfq;
|
|
|
|
sstfq = (RF_Sstf_t *) qptr;
|
|
|
|
if ((sstfq->left.queue == NULL) && (sstfq->right.queue == NULL)) {
|
|
req = closest_to_arm(&sstfq->lopri, sstfq->last_sector, &sstfq->dir,
|
|
sstfq->allow_reverse);
|
|
} else {
|
|
if (sstfq->left.queue == NULL)
|
|
req = sstfq->right.queue;
|
|
else {
|
|
if (sstfq->right.queue == NULL)
|
|
req = sstfq->left.queue;
|
|
else {
|
|
if (SNUM_DIFF(sstfq->last_sector, sstfq->right.queue->sectorOffset)
|
|
< SNUM_DIFF(sstfq->last_sector, sstfq->left.qtail->sectorOffset)) {
|
|
req = sstfq->right.queue;
|
|
} else {
|
|
req = sstfq->left.qtail;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (req == NULL) {
|
|
RF_ASSERT(QSUM(sstfq) == 0);
|
|
}
|
|
return (req);
|
|
}
|
|
|
|
RF_DiskQueueData_t *
|
|
rf_ScanPeek(qptr)
|
|
void *qptr;
|
|
{
|
|
RF_DiskQueueData_t *req;
|
|
RF_Sstf_t *scanq;
|
|
int dir;
|
|
|
|
scanq = (RF_Sstf_t *) qptr;
|
|
dir = scanq->dir;
|
|
|
|
if (scanq->left.queue == NULL) {
|
|
RF_ASSERT(scanq->left.qlen == 0);
|
|
if (scanq->right.queue == NULL) {
|
|
RF_ASSERT(scanq->right.qlen == 0);
|
|
if (scanq->lopri.queue == NULL) {
|
|
RF_ASSERT(scanq->lopri.qlen == 0);
|
|
return (NULL);
|
|
}
|
|
req = closest_to_arm(&scanq->lopri, scanq->last_sector,
|
|
&dir, scanq->allow_reverse);
|
|
} else {
|
|
req = scanq->right.queue;
|
|
}
|
|
} else
|
|
if (scanq->right.queue == NULL) {
|
|
RF_ASSERT(scanq->right.qlen == 0);
|
|
RF_ASSERT(scanq->left.queue);
|
|
req = scanq->left.qtail;
|
|
} else {
|
|
RF_ASSERT(scanq->right.queue);
|
|
RF_ASSERT(scanq->left.queue);
|
|
if (scanq->dir == DIR_RIGHT) {
|
|
req = scanq->right.queue;
|
|
} else {
|
|
req = scanq->left.qtail;
|
|
}
|
|
}
|
|
if (req == NULL) {
|
|
RF_ASSERT(QSUM(scanq) == 0);
|
|
}
|
|
return (req);
|
|
}
|
|
|
|
RF_DiskQueueData_t *
|
|
rf_CscanPeek(qptr)
|
|
void *qptr;
|
|
{
|
|
RF_DiskQueueData_t *req;
|
|
RF_Sstf_t *cscanq;
|
|
|
|
cscanq = (RF_Sstf_t *) qptr;
|
|
|
|
RF_ASSERT(cscanq->dir == DIR_RIGHT);
|
|
if (cscanq->right.queue) {
|
|
req = cscanq->right.queue;
|
|
} else {
|
|
RF_ASSERT(cscanq->right.qlen == 0);
|
|
if (cscanq->left.queue == NULL) {
|
|
RF_ASSERT(cscanq->left.qlen == 0);
|
|
if (cscanq->lopri.queue == NULL) {
|
|
RF_ASSERT(cscanq->lopri.qlen == 0);
|
|
return (NULL);
|
|
}
|
|
req = closest_to_arm(&cscanq->lopri, cscanq->last_sector,
|
|
&cscanq->dir, cscanq->allow_reverse);
|
|
} else {
|
|
/*
|
|
* There's I/Os to the left of the arm. We'll end
|
|
* up swinging on back.
|
|
*/
|
|
req = cscanq->left.queue;
|
|
}
|
|
}
|
|
if (req == NULL) {
|
|
RF_ASSERT(QSUM(cscanq) == 0);
|
|
}
|
|
return (req);
|
|
}
|
|
|
|
int
|
|
rf_SstfPromote(qptr, parityStripeID, which_ru)
|
|
void *qptr;
|
|
RF_StripeNum_t parityStripeID;
|
|
RF_ReconUnitNum_t which_ru;
|
|
{
|
|
RF_DiskQueueData_t *r, *next;
|
|
RF_Sstf_t *sstfq;
|
|
int n;
|
|
|
|
sstfq = (RF_Sstf_t *) qptr;
|
|
|
|
n = 0;
|
|
for (r = sstfq->lopri.queue; r; r = next) {
|
|
next = r->next;
|
|
if (rf_sstfDebug || rf_scanDebug || rf_cscanDebug) {
|
|
printf("raid%d: check promote %lx\n",
|
|
r->raidPtr->raidid, (long) r);
|
|
}
|
|
if ((r->parityStripeID == parityStripeID)
|
|
&& (r->which_ru == which_ru)) {
|
|
do_dequeue(&sstfq->lopri, r);
|
|
rf_SstfEnqueue(qptr, r, RF_IO_NORMAL_PRIORITY);
|
|
n++;
|
|
}
|
|
}
|
|
if (rf_sstfDebug || rf_scanDebug || rf_cscanDebug) {
|
|
printf("raid%d: promoted %d matching I/Os queues are %d,%d,%d\n",
|
|
r->raidPtr->raidid, n, sstfq->left.qlen,
|
|
sstfq->right.qlen, sstfq->lopri.qlen);
|
|
}
|
|
return (n);
|
|
}
|